An eye focusing problem that is unrelated to aging changes in the lens of the eye.
Amblyopia / Lazy Eye
The loss or lack of development of clear vision in just one eye. It is not due to eye health problems and eyeglasses or contact lenses can’t fully correct the reduced vision caused by lazy eye.
A vision condition that causes blurred vision due either to the irregular shape of the cornea, the clear front cover of the eye, or sometimes the curvature of the lens inside the eye. (LEARN MORE)
An inflammation of the eyelids and eyelashes causing red, irritated, itchy eyelids and the formation of dandruff like scales on eyelashes.
A cloudy or opaque area in the normally clear lens of the eye. (LEARN MORE)
A slowly developing lump that forms due to blockage and swelling of an oil gland in the eyelid.
Color Vision Deficiency
The inability to distinguish certain shades of colors or, in more severe cases, see colors at all.
Computer Vision Syndrome
A group of eye and vision-related problems that result from prolonged computer use.
An inflammation or infection of the conjunctiva, the thin transparent layer of tissue that lines the inner surface of the eyelid and covers the white part of the eye. (LEARN MORE)
An eye coordination problem in which the eyes have a tendency to drift outward when reading or doing close work.
A cut or scratch on the cornea, the clear front cover of the eye.
Crossed Eyes / Strabismus
A condition in which both eyes do not look at the same place at the same time.
A condition occurring in persons with diabetes, which causes progressive damage to the retina, the light sensitive lining at the back of the eye. (LEARN MORE)
A condition in which there are insufficient tears to lubricate and nourish the eye. (LEARN MORE)
Farsightedness / Hyperopia
A vision condition in which distant objects are usually seen clearly, but close objects do not come into proper focus.
Floaters & Spots
The shadowy images that are seen moving in your field of vision caused by particles floating in the fluid that fills the inside of the eye.
A group of disorders leading to progressive damage to the optic nerve, and is characterized by loss of nerve tissue resulting in loss of vision.
Hordeolum / Sty
An infection of an oil gland in the eyelid.
An inflammation or infection of the cornea, the clear front cover of the eye.
An eye disorder causing progressive thinning and bulging of the cornea, the clear front cover of the eye. (LEARN MORE)
The loss or lack of development of clear vision in just one eye. It is not due to eye health problems and eyeglasses or contact lenses can’t fully correct the reduced vision caused by lazy eye.
Learning-Related Vision Problems
Vision disorders that interfere with reading and learning.
An eye disease affecting the macula, the center of the light sensitive retina at the back of the eye, causing loss of central vision. (LEARN MORE)
Migraine with Aura / Ocular Migraine
A type of severe headache accompanied by various visual symptoms.
Myopia / Nearsightedness
A vision condition in which you can see close objects clearly, but objects farther away are blurred.
A vision condition in which the eyes make repetitive, uncontrolled movements, often resulting in reduced vision.
The abnormal response of sensitive eyes to contact with allergens and other irritating substances.
An increase in the pressure inside the eye above the range considered normal, without any detectable changes in vision or damage to the structures of the eye. (LEARN MORE)
An abnormal growth of tissue on the conjunctiva, the clear membrane that covers the white of the eye.
An age-related vision condition in which there is a gradual loss of the eye’s ability to focus on near objects. (LEARN MORE)
An abnormal growth of tissue on the conjuctiva, the clear membrane that covers the white of the eye, and the adjacent cornea, the clear front surface of the eye.
A drooping of the upper eyelid.
A tearing or separation of the retina, the light sensitive lining at the back of the eye, from the underlying tissue.
A group of inherited disorders of the retina, the light sensitive lining at the back of the eye, which cause poor night vision and a progressive loss of side vision.
A rare type of eye cancer occurring in young children that develops in the retina, the light sensitive lining at the back of the eye.
An accumulation of blood underneath the conjunctiva, the clear membrane covering the white part of the eye.
An inflammation of one or more of the structures that make up the middle layer of the eye called the uvea.
EYE & VISION CONDITIONS
Astigmatism is a vision condition that causes blurred vision due either to the irregular shape of the cornea, the clear front cover of the eye, or sometimes the curvature of the lens inside the eye. An irregular shaped cornea or lens prevents light from focusing properly on the retina, the light sensitive surface at the back of the eye. As a result, vision becomes blurred at any distance. Astigmatism is a very common vision condition. Most people have some degree of astigmatism. Slight amounts of astigmatism usually don’t affect vision and don’t require treatment. However, larger amounts cause distorted or blurred vision, eye discomfort and headaches. Astigmatism frequently occurs with other vision conditions like nearsightedness (myopia) and farsightedness (hyperopia). Together these vision conditions are referred to as refractive errors because they affect how the eyes bend or “refract” light.
The specific cause of astigmatism is unknown. It can be hereditary and is usually present from birth. It can change as a child grows and may decrease or worsen over time. A comprehensive optometric examination will include testing for astigmatism. Depending on the amount present, your optometrist can provide eyeglasses or contact lenses that correct the astigmatism by altering the way light enters your eyes.
Another option for treating astigmatism uses a corneal modification procedure called orthokeratology (ortho-k). It is a painless, non-invasive procedure that involves wearing a series of specially designed rigid contact lenses to gradually reshape the curvature of the cornea. Laser surgery is also a possible treatment option for some types of astigmatism. It changes the shape of the cornea by removing a small amount of eye tissue. This is done using a highly focused laser beam on the surface of the eye.
What causes astigmatism?
Astigmatism occurs due to the irregular shape of the cornea or the lens inside the eye. The cornea and lens are primarily responsible for properly focusing light entering your eyes allowing you to see things clearly.
The curvature of the cornea and lens causes light entering the eye to be bent in order to focus it precisely on the retina at the back of the eye. In astigmatism, the surface of the cornea or lens has a somewhat different curvature in one direction than another. In the case of the cornea, instead of having a round shape like a basketball, the surface of the cornea is more like a football. As a result, the eye is unable to focus light rays to a single point causing vision to be out of focus at any distance.
Sometimes astigmatism may develop following an eye injury or eye surgery. There is also a relatively rare condition called keratoconus where the cornea becomes progressively thinner and cone shaped. This results in a large amount of astigmatism resulting in poor vision that cannot be clearly corrected with spectacles. Keratoconus usually requires contact lenses for clear vision, and it may eventually progress to a point where a corneal transplant is necessary.
How is astigmatism diagnosed?
Astigmatism can be diagnosed through a comprehensive eye examination. Testing for astigmatism measures how the eyes focus light and determines the power of any optical lenses needed to compensate for reduced vision. This examination may include:
- Visual acuity—As part of the testing, you’ll be asked to read letters on a distance chart. This test measures visual acuity, which is written as a fraction such as 20/40. The top number is the standard distance at which testing is done, twenty feet. The bottom number is the smallest letter size you were able to read. A person with 20/40 visual acuity would have to get within 20 feet of a letter that should be seen at forty feet in order to see it clearly. Normal distance visual acuity is 20/20.
- Keratometry—A keratometer is the primary instrument used to measure the curvature of the cornea. By focusing a circle of light on the cornea and measuring its reflection, it is possible to determine the exact curvature of the cornea’s surface. This measurement is particularly critical in determining the proper fit for contact lenses. A more sophisticated procedure called corneal topography may be performed in some cases to provide even more detail of the shape of the cornea.
- Refraction—Using an instrument called a phoropter, your optometrist places a series of lenses in front of your eyes and measures how they focus light. This is performed using a hand held lighted instrument called a retinoscope or an automated instrument that automatically evaluates the focusing power of the eye. The power is then refined by patient’s responses to determine the lenses that allow the clearest vision.
Using the information obtained from these tests, your optometrist can determine if you have astigmatism. These findings, combined with those of other tests performed, will allow the optometrist to determine the power of any lens correction needed to provide clear, comfortable vision, and discuss options for treatment.
How is astigmatism treated?
Persons with astigmatism have several options available to regain clear vision. They include:
- Contact lenses
- Laser and other refractive surgery procedures
Eyeglasses are the primary choice of correction for persons with astigmatism. They will contain a special cylindrical lens prescription to compensate for the astigmatism. This provides for additional lens power in only specific meridians of the lens. An example of a prescription for astigmatism for one eye would be -1.00 -1.25 X 180. The middle number (-1.25) is the lens power for correction of the astigmatism. The “X 180” designates the placement (axis) of the lens power. The first number (-1.00) indicates that this prescription also includes a correction for nearsightedness in addition to astigmatism.
Generally, a single vision lens is prescribed to provide clear vision at all distances. However, for patients over about age 40 who have the condition called presbyopia, a bifocal or progressive addition lens may be needed. These provide different lens powers to see clearly in the distance and to focus effectively for near vision work. A wide variety of lens types and frame designs are now available for patients of all ages. Eyeglasses are no longer just a medical device that provides needed vision correction. Eyeglass frames are available in a many shapes, sizes, colors and materials that not only allow for correction of vision, but also enhance appearance.
For some individuals, contact lenses can offer better vision than eyeglasses. They may provide clearer vision and a wider field of view. However, since contact lenses are worn directly on the eyes, they require regular cleaning and care to safeguard eye health. Soft contact lenses conform to the shape of the eye, therefore standard soft lenses may not be effective in correcting astigmatism. However, special toric soft contact lenses are available to provide a correction for many types of astigmatism. Because rigid gas permeable contact lenses maintain their regular shape while on the cornea, they offer an effective way to compensate for the cornea’s irregular shape and improve vision for persons with astigmatism and other refractive errors.
Orthokeratology (Ortho-K) involves the fitting of a series of rigid contact lenses to reshape the cornea, the front outer cover of the eye. The contact lenses are worn for limited periods, such as overnight, and then removed. Persons with moderate amounts of astigmatism may be able to temporarily obtain clear vision without lenses for most of their daily activities. Orthokeratology does not permanently improve vision and if you stop wearing the retainer lenses, your vision may return to its original condition.
Astigmatism can also be corrected by reshaping the cornea using a highly focused laser beam of light. Two commonly used procedures are photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). PRK removes tissue from the superficial and inner layers of the cornea. LASIK does not remove tissue from the surface of the cornea, but only from its inner layer. To do this, a section of outer corneal surface is cut and folded back to expose the inner tissue. Then a laser is used to remove the precise amount of tissue needed and the flap of outer tissue is placed back in position to heal. Both procedures allow light to focus on the retina by altering the shape of the cornea.
Individuals with astigmatism have a wide range of options to correct their vision problem. In consultation with your optometrist, you can select the treatment that best meets your visual and lifestyle needs.
Rarely, cataracts can be present at birth or develop shortly after. They may be inherited or develop due to an infection, i.e. rubella, in the mother during pregnancy. A cataract may also develop following an injury to the eye or surgery for another eye problem, such as glaucoma.
While there are no clinically proven approaches to preventing cataracts, simple preventive strategies include reducing exposure to sunlight through UV blocking lenses, decreasing or discontinuing smoking and increasing antioxidant vitamin intake through consumption of leafy green vegetables and nutritional supplements.
Diagnosis of Cataracts
Cataracts can be diagnosed through a comprehensive eye examination. This examination may include:
- Patient history to determine vision difficulties experienced by the patient that may limit their daily activities and other general health concerns affecting vision.
- Visual acuity measurement to determine to what extent a cataract may be limiting clear vision at distance and near.
- Refraction to determine the need for changes in an eyeglass or contact lens prescription.
- Evaluation of the lens under high magnification and illumination to determine the extent and location of any cataracts.
- Evaluation of the retina of the eye through a dilated pupil.
- Measurement of pressure within the eye.
- Supplemental testing for color vision and glare sensitivity.
Additional testing may be needed to determine the extent of impairment to vision caused by a cataract and to evaluate whether other eye diseases may limit vision following cataract surgery.
Using the information obtained from these tests, your optometrist can determine if you have cataracts and advise you on options for treatment.
How is a cataract treated?
The treatment of cataracts is based on the level of visual impairment they cause.
If a cataract affects vision only minimally, or not at all, no treatment may be needed. Patients may be advised to monitor for increased visual symptoms and follow a regular check-up schedule.
In some cases, a change in eyeglass prescription may provide temporary improvement in visual acuity. Increasing the amount of light used when reading may be beneficial. The use of anti-glare coatings on clear lenses can help reduce glare for night driving.
When a cataract progresses to the point that it affects a person’s ability to do normal everyday tasks, surgery may be needed. Cataract surgery involves removing the lens of the eye and replacing it with an artificial lens. The artificial lens requires no care and can significantly improve vision. New artificial lens options include those that simulate the natural focusing ability of a young healthy lens.
Two approaches to cataract surgery are generally used:
- Small incision cataract surgery involves making an incision in the side of the cornea, the clear outer covering of the eye, and inserting a tiny probe into the eye. The probe emits ultrasound waves that soften and break-up the lens so it can be removed by suction. This process is called phacoemulsification.
- Extracapsular surgery requires a somewhat larger incision in the cornea and the lens core is removed in one piece.
Once the natural lens has been removed, it is replaced by a clear plastic lens called an intraocular lens (IOL). For situations where implanting an IOL is not possible because of other eye problems, contact lenses and in some cases eyeglasses may be an option to provide needed vision correction.
As with any surgery, cataract surgery has risks from infection and bleeding. Cataract surgery also slightly increases the risk of retinal detachment. It is important to discuss the benefits and risks of cataract surgery with your eye care providers. Other ocular conditions may increase the need for cataract surgery or prevent a person from being a cataract surgery candidate.
Cataract surgery is one of the safest and most effective types of surgery performed in the United States today. Approximately 90 percent of cataract surgery patients report better vision following the surgery.
The Importance of Nutrition
A cataract is a cloudy or opaque area in the normally clear lens of the eye. Depending upon its size and location, it can interfere with normal vision. Most cataracts develop in people over age 55, but they occasionally occur in infants and young children. Usually cataracts develop in both eyes, but one may be worse than the other. Reasearchers have linked eye-friendly nutrients such as lutein/zeaxanthin, vitamin C, vitamin E, and zinc to reducing the risk of certain eye diseases, including cataracts. For more information on the importance of good nutrition and eye health, please see the diet and nutrition section.
The lens is located inside the eye behind the iris, the colored part of the eye. The lens focuses light on the back of the eye, the retina. The lens is made of mostly proteins and water. Clouding of the lens occurs due to changes in the proteins and lens fibers.
The lens is composed of layers like an onion. The outermost is the capsule. The layer inside the capsule is the cortex, and the innermost layer is the nucleus. A cataract may develop in any of these areas and is described based on its location in the lens:
- A nuclear cataract is located in the center of the lens. The nucleus tends to darken changing from clear to yellow and sometimes brown.
- A cortical cataract affects the layer of the lens surrounding the nucleus. It is identified by its unique wedge or spoke appearance.
- A posterior capsular cataract is found in the back outer layer of the lens. This type often develops more rapidly.
Normally, the lens focuses light on the retina, which sends the image through the optic nerve to the brain. However, if the lens is clouded by a cataract, light is scattered so the lens can no longer focus it properly, causing vision problems.
Cataracts generally form very slowly. Signs and symptoms of a cataract may include:
- Blurred or hazy vision
- Reduced intensity of colors
- Increased sensitivity to glare from lights, particularly when driving at night
- Increased difficulty seeing at night
- Change in the eye’s refractive error
While the process of cataract formation is becoming more clearly understood, there is no clinically established treatment to prevent or slow their progression. In age-related cataracts, changes in vision can be very gradual. Some people may not initially recognize the visual changes. However, as cataracts worsen vision symptoms tend to increase in severity.
Causes of Cataracts?
Most cataracts are due to age-related changes in the lens. However, other factors can contribute to their development including:
- Diabetes Mellitus Persons with diabetes are at higher risk for cataracts.
- Drugs Certain medications have been found to be associated with the development of a cataract. These include: Corticosteroids and Chlorpromazine and other phenothiazine related medications
- Ultraviolet Radiation Studies have shown that there is an increased chance of cataract formation with unprotected exposure to ultraviolet (UV) radiation.
- Smoking An association between smoking and increased nuclear opacities has been reported.
- Alcohol Several studies have shown increased cataract formation in patients with higher alcohol consumption compared with people who have lower or no alcohol consumption.
- Nutritional Deficiency Although the results are inconclusive, studies have suggested an association between cataract formation and low levels of antioxidants (e.g. vitamin C, vitamin E, carotenoids). Further studies may show that antioxidants have a significant effect on decreasing cataract development.
Conjunctivitis is an inflammation or infection of the conjunctiva, the thin transparent layer of tissue that lines the inner surface of the eyelid and covers the white part of the eye. Conjunctivitis, often called “pink eye,” is a common eye disease, especially in children. It may affect one or both eyes. Some forms of conjunctivitis can be highly contagious and easily spread in schools and at home. While conjunctivitis is usually a minor eye infection, sometimes it can develop into a more serious problem.
Conjunctivitis may be caused by a viral or bacterial infection. It can also occur due to an allergic reaction to irritants in the air like pollen and smoke, chlorine in swimming pools, and ingredients in cosmetics or other products that come in contact with the eyes. Sexually transmitted diseases like Chlamydia and gonorrhea are less common causes of conjunctivitis.
People with conjunctivitis may experience the following symptoms:
- A gritty feeling in one or both eyes
- Itching or burning sensation in one or both eyes
- Excessive tearing
- Discharge coming from one or both eyes
- Swollen eyelids
- Pink discoloration to the whites of one or both eyes
- Increased sensitivity to light
What causes conjunctivitis?
The cause of conjunctivitis varies depending on the offending agent. There are three main categories of conjunctivitis: allergic, infectious and chemical:
- Allergic Conjunctivitis occurs more commonly among people who already have seasonal allergies. At some point they come into contact with a substance that triggers an allergic reaction in their eyes.
- Giant Papillary Conjunctivitis is a type of allergic conjunctivitis caused by the chronic presence of a foreign body in the eye. This condition occurs predominantly with people who wear hard or rigid contact lenses, wear soft contact lenses that are not replaced frequently, have an exposed suture on the surface or the eye, or have a glass eye.
- Bacterial Conjunctivitis is an infection most often caused by staphylococcal or streptococcal bacteria from your own skin or respiratory system. Infection can also occur by transmittal from insects, physical contact with other people, poor hygiene (touching the eye with unclean hands), or by use of contaminated eye makeup and facial lotions.
- Viral Conjunctivitis is most commonly caused by contagious viruses associated with the common cold. The primary means of contracting this is through exposure to coughing or sneezing by persons with upper respiratory tract infections. It can also occur as the virus spreads along the body’s own mucous membranes connecting lungs, throat, nose, tear ducts, and conjunctiva.
- Ophthalmia Neonatorum is a severe form of bacterial conjunctivitis that occurs in newborn babies. This is a serious condition that could lead to permanent eye damage unless it is treated immediately. Ophthalmia neonatorum occurs when an infant is exposed to Chlamydia or gonorrhea while passing through the birth canal.
Chemical Conjunctivitis can be caused by irritants like air pollution, chlorine in swimming pools, and exposure to noxious chemicals.
How is conjunctivitis diagnosed?
Conjunctivitis can be diagnosed through a comprehensive eye examination. Testing, with special emphasis on evaluation of the conjunctiva and surrounding tissues, may include:
- Patient history to determine the symptoms the patient is experiencing, when the symptoms began, and the presence of any general health or environmental conditions that may be contributing to the problem.
- Visual acuity measurements to determine the extent to which vision may be affected.
- Evaluation of the conjunctiva and external eye tissue using bright light and magnification.
- Evaluation of the inner structures of the eye to ensure that no other tissues are affected by the condition.
- Supplemental testing may include taking cultures or smears of conjunctival tissue, particularly in cases of chronic conjunctivitis or when the condition is not responding to treatment.
Using the information obtained from these tests, your optometrist can determine if you have conjunctivitis and advise you on treatment options.
How is conjunctivitis treated?
Treatment of conjunctivitis is directed at three main goals:
- To increase patient comfort.
- To reduce or lessen the course of the infection or inflammation.
- To prevent the spread of the infection in contagious forms of conjunctivitis.
The appropriate treatment for conjunctivitis depends on its cause:
- Allergic conjunctivitis—The first step should be to remove or avoid the irritant, if possible. Cool compresses and artificial tears sometimes relieve discomfort in mild cases. In more severe cases, non-steroidal anti-inflammatory medications and antihistamines may be prescribed. Cases of persistent allergic conjunctivitis may also require topical steroid eye drops.
- Bacterial conjunctivitis—This type of conjunctivitis is usually treated with antibiotic eye drops or ointments. Improvement can occur after three or four days of treatment, but the entire course of antibiotics needs to be used to prevent recurrence.
- Viral Conjunctivitis—There are no available drops or ointments to eradicate the virus for this type of conjunctivitis. Antibiotics will not cure a viral infection. Like a common cold, the virus just has to run its course, which may take up to two or three weeks in some cases. The symptoms can often be relieved with cool compresses and artificial tear solutions. For the worst cases, topical steroid drops may be prescribed to reduce the discomfort from inflammation, but do not shorten the course of the infection. Some doctors may perform an ophthalmic iodine eye wash in the office in hopes of shortening the course of the infection. This newer treatment has not been well studied yet, therefore no conclusive evidence of the success exists.
- Chemical Conjunctivitis—Treatment for chemical conjunctivitis requires careful flushing of the eyes with saline and may require topical steroids. The more acute chemical injuries are medical emergencies, particularly alkali burns, which can lead to severe scarring, intraocular damage or even loss of the eye.
Contact Lens Wearers
Contact lens wearers may need to discontinue wearing their lenses while the conjunctivitis is active.Contact lens wearers may need to discontinue wearing their lenses while the condition is active. Your doctor can advise you on the need for temporary restrictions on contact lens wear.
If the conjunctivitis developed due to wearing contact lenses, your eye doctor may recommend that you switch to a different type of contact lens or disinfection solution. Your optometrist might need to alter your contact lense prescription to a type of lens that you replace more frequently to prevent the conjunctivitis from recurring.
Practicing good hygiene is the best way to control the spread of conjunctivitis. Once an infection has been diagnosed, follow these steps:
- Don’t touch your eyes with your hands.
- Wash your hands thoroughly and frequently.
- Change your towel and washcloth daily, and don’t share them with others.
- Discard eye cosmetics, particularly mascara.
- Don’t use anyone else’s eye cosmetics or personal eye-care items.
- Follow your eye doctor’s instructions on proper contact lens care.
You can soothe the discomfort of viral or bacterial conjunctivitis by applying warm compresses to your affected eye or eyes. To make a compress, soak a clean cloth in warm water and wring it out before applying it gently to your closed eyelids.
For allergic conjunctivitis, avoid rubbing your eyes. Instead of warm compresses, use cool compresses to soothe your eyes. Over the counter eye drops are available. Antihistamine eye drops should help to alleviate the symptoms, and lubricating eye drops help to rinse the allergen off of the surface of the eye.
See your doctor of optometry when you experience conjunctivitis to help diagnose the cause and the proper course of action.
Diabetic retinopathy is a condition occurring in persons with diabetes, which causes progressive damage to the retina, the light sensitive lining at the back of the eye. It is a serious sight-threatening complication of diabetes.
Diabetes is a disease that interferes with the body’s ability to use and store sugar, which can cause many health problems. Too much sugar in the blood can cause damage throughout the body, including the eyes. Over time, diabetes affects the circulatory system of the retina.
Diabetic retinopathy is the result of damage to the tiny blood vessels that nourish the retina. They leak blood and other fluids that cause swelling of retinal tissue and clouding of vision. The condition usually affects both eyes. The longer a person has diabetes, the more likely they will develop diabetic retinopathy. If left untreated, diabetic retinopathy can cause blindness.
Symptoms of diabetic retinopathy include:
- Seeing spots or floaters in your field of vision
- Blurred vision
- Having a dark or empty spot in the center of your vision
- Difficulty seeing well at night
In patients with diabetes, prolonged periods of high blood sugar can lead to the accumulation of fluid in the lens inside the eye that controls eye focusing. This changes the curvature of the lens and results in the development of symptoms of blurred vision. The blurring of distance vision as a result of lens swelling will subside once the blood sugar levels are brought under control. Better control of blood sugar levels in patients with diabetes also slows the onset and progression of diabetic retinopathy.
Often there are no visual symptoms in the early stages of diabetic retinopathy. That is why the American Optometric Association recommends that everyone with diabetes have a comprehensive dilated eye examination once a year. Early detection and treatment can limit the potential for significant vision loss from diabetic retinopathy.
Treatment of diabetic retinopathy varies depending on the extent of the disease. It may require laser surgery to seal leaking blood vessels or to discourage new leaky blood vessels from forming. Injections of medications into the eye may be needed to decrease inflammation or stop the formation of new blood vessels. In more advanced cases, a surgical procedure to remove and replace the gel-like fluid in the back of the eye, called the vitreous, may be needed. A retinal detachment, defined as a separation of the light-receiving lining in the back of the eye, resulting from diabetic retinopathy, may also require surgical repair.
If you are a diabetic, you can help prevent or slow the development of diabetic retinopathy by taking your prescribed medication, sticking to your diet, exercising regularly, controlling high blood pressure and avoiding alcohol and smoking.
What causes diabetic retinopathy?
Diabetic retinopathy is classified into two types:
- Non-proliferative diabetic retinopathy (NPDR) is the early state of the disease in which symptoms will be mild or non-existent. In NPDR, the blood vessels in the retina are weakened causing tiny bulges called microanuerysms to protrude from their walls. The microanuerysms may leak fluid into the retina, which may lead to swelling of the macula.
- Proliferative diabetic retinopathy (PDR) is the more advanced form of the disease. At this stage, circulation problems cause the retina to become oxygen deprived. As a result new fragile blood vessels can begin to grow in the retina and into the vitreous, the gel-like fluid that fills the back of the eye. The new blood vessel may leak blood into the vitreous, clouding vision. Other complications of PDR include detachment of the retina due to scar tissue formation and the development of glaucoma. Glaucoma is an eye disease defined as progressive damage to the optic nerve. In cases of proliferative diabetic retinopathy, the cause of this nerve damage is due to extremely high pressure in the eye. If left untreated, proliferative diabetic retinopathy can cause severe vision loss and even blindness.
Risk factors for diabetic retinopathy include:
- Diabetes People with Type 1 or Type 2 diabetes are at risk for the development of diabetic retinopathy. The longer a person has diabetes, the more likely they are to develop diabetic retinopathy, particularly if the diabetes is poorly controlled.
- Race Hispanic and African Americans are at greater risk for developing diabetic retinopathy.
- Medical Conditions Persons with other medical conditions such as high blood pressure and high cholesterol are at greater risk.
- Pregnancy Pregnant women face a higher risk for developing diabetes and diabetic retinopathy. If gestational diabetes develops, the patient is at much higher risk of developing diabetes as they age.
How is diabetic retinopathy diagnosed?
Diabetic retinopathy can be diagnosed through a comprehensive eye examination. Testing, with special emphasis on evaluation of the retina and macula, may include:
- Patient history to determine vision difficulties experienced by the patient, presence of diabetes, and other general health concerns that may be affecting vision
- Visual acuity measurements to determine the extent to which central vision has been affected
- Refraction to determine the need for changes in an eyeglass prescription
- Evaluation of the ocular structures, including the evaluation of the retina through a dilated pupil
- Measurement of the pressure within the eye
Supplemental testing may include:
- Retinal photography or tomography to document current status of the retina
- Fluorescein angiography to evaluate abnormal blood vessel growth
How is diabetic retinopathy treated?
Treatment for diabetic retinopathy depends on the stage of the disease and is directed at trying to slow or stop the progression of the disease.
In the early stages of Non-proliferative Diabetic Retinopathy, treatment other than regular monitoring may not be required. Following your doctor’s advice for diet and exercise and keeping blood sugar levels well-controlled can help control the progression of the disease.
If the disease advances, leakage of fluid from blood vessels can lead to macular edema. Laser treatment (photocoagulation) is used to stop the leakage of blood and fluid into the retina. A laser beam of light can be used to create small burns in areas of the retina with abnormal blood vessels to try to seal the leaks.
When blood vessel growth is more widespread throughout the retina, as in proliferative diabetic retinopathy, a pattern of scattered laser burns is created across the retina. This causes abnormal blood vessels to shrink and disappear. With this procedure, some side vision may be lost in order to safeguard central vision.
Some bleeding into the vitreous gel may clear up on its own. However, if significant amounts of blood leak into the vitreous fluid in the eye, it will cloud vision and can prevent laser photocoagulation from being used. A surgical procedure called a vitrectomy may be used to remove the blood-filled vitreous and replace it with a clearfluid to maintain the normal shape and health of the eye.
Persons with diabetic retinopathy can suffer significant vision loss. Special low vision devices such as telescopic and microscopic lenses, hand and stand magnifiers, and video magnification systems can be prescribed to make the most of remaining vision.
Dry eye is a condition in which there are insufficient tears to lubricate and nourish the eye. Tears are necessary for maintaining the health of the front surface of the eye and for providing clear vision. People with dry eyes either do not produce enough tears or have a poor quality of tears. Dry eye is a common and often chronic problem, particularly in older adults.
With each blink of the eyelids, tears are spread across the front surface of the eye, known as the cornea. Tears provide lubrication, reduce the risk of eye infection, wash away foreign matter in the eye, and keep the surface of the eyes smooth and clear. Excess tears in the eyes flow into small drainage ducts, in the inner corners of the eyelids, which drain in the back of the nose.
Dry eyes can result from an improper balance of tear production and drainage.
- Inadequate amount of tears—Tears are produced by several glands in and around the eyelids. Tear production tends to diminish with age, with various medical conditions, or as a side effect of certain medicines. Environmental conditions such as wind and dry climates can also affect tear volume by increasing tear evaporation. When the normal amount of tear production decreases or tears evaporate too quickly from the eyes, symptoms of dry eye can develop.
- Poor quality of tears—Tears are made up of three layers: oil, water, and mucus. Each component serves a function in protecting and nourishing the front surface of the eye. A smooth oil layer helps to prevent evaporation of the water layer, while the mucin layer functions in spreading the tears evenly over the surface of the eye. If the tears evaporate too quickly or do not spread evenly over the cornea due to deficiencies with any of the three tear layers, dry eye symptoms can develop.
The most common form of dry eyes is due to an inadequate amount of the water layer of tears. This condition, called keratoconjunctivitis sicca (KCS), is also referred to as dry eye syndrome.
People with dry eyes may experience symptoms of irritated, gritty, scratchy, or burning eyes, a feeling of something in their eyes, excess watering, and blurred vision. Advanced dry eyes may damage the front surface of the eye and impair vision.
Treatments for dry eyes aim to restore or maintain the normal amount of tears in the eye to minimize dryness and related discomfort and to maintain eye health.
What causes dry eyes?
The development of dry eyes can have many causes. They include:
- Age — dry eye is a part of the natural aging process. The majority of people over age 65 experience some symptoms of dry eyes.
- Gender — women are more likely to develop dry eyes due to hormonal changes caused by pregnancy, the use of oral contraceptives, and menopause.
- Medications — certain medicines, including antihistamines, decongestants, blood pressure medications and antidepressants, can reduce the amount of tears produced in the eyes.
- Medical Conditions — persons with rheumatoid arthritis, diabetes and thyroid problems are more likely to have symptoms of dry eyes. Also, problems with inflammation of the eyelids (blepharitis), inflammation of the surfaces of the eye, or the inward or outward turning of eyelids can cause dry eyes to develop.
- Environmental Conditions — exposure to smoke, wind and dry climates can increase tear evaporation resulting in dry eye symptoms. Failure to blink regularly, such as when staring at a computer screen for long periods of time, can also contribute to drying of the eyes.
- Other Factors — long term use of contact lenses can be a factor in the development of dry eyes. Refractive eye surgeries, such as LASIK, can cause decreased tear production and dry eyes.
How are dry eyes diagnosed?
Dry eyes can be diagnosed through a comprehensive eye examination. Testing, with special emphasis on the evaluation of the quantity and quality of tears produced by the eyes, may include:
- Patient history to determine any symptoms the patient is experiencing and the presence of any general health problems, medications taken, or environmental factors that may be contributing to the dry eye problem.
- External examination of the eye, including lid structure and blink dynamics.
- Evaluation of the eyelids and cornea using bright light and magnification.
- Measurement of the quantity and quality of tears for any abnormalities. Special dyes may be instilled in the eyes to better observe tear flow and to highlight any changes to the outer surface of the eye caused by insufficient tears.
Using the information obtained from testing, your optometrist can determine if you have dry eyes and advise you on treatment options.
How are dry eyes treated?
Dry eyes can be a chronic condition, but your optometrist can prescribe treatment to keep your eyes healthy, more comfortable, and prevent your vision from being affected. The primary approaches used to manage and treat dry eyes include adding tears, conserving tears, increasing tear production, and treating the inflammation of the eyelids or eye surface that contributes to the dry eyes.
- Adding Tears — Mild cases of dry eyes can often be managed using over-the-counter artificial tear solutions. These can be used as often as needed to supplement natural tear production. Preservative-free artificial tear solutions are recommended because they contain fewer additives that could further irritate the eyes. However, some people may have persistent dry eyes that don’t respond to artificial tears alone. Additional steps need to be taken to treat their dry eyes.
- Conserving Tears — An additional approach to reducing the symptoms of dry eyes is to keep natural tears in the eyes longer. This can be done by blocking the tear ducts through which the tears normally drain. The tear ducts can be blocked with tiny silicone or gel-like plugs that can be removed, if needed. A surgical procedure to permanently close tear ducts can also be used. In either
- Increasing Tear Production — Prescription eye drops that help to increase production of tears can be recommended by your optometrist, as well as omega-3 fatty acid nutritional supplements.
- Treatment of the Contributing Eyelid or Ocular Surface Inflammation — Prescription eye drops or ointments, warm compresses and lid massage, or eyelid cleaners may be recommended to help decrease inflammation around the surface of the eyes.
Steps you can take to reduce symptoms of dry eyes include:
- Remembering to blink regularly when reading or staring at a computer screen for long periods of time.
- Increasing the level of humidity in the air at work and at home.
- Wearing sunglasses outdoors, particularly those with wrap around frame design, to reduce exposure to drying winds and sun.
- Using nutritional supplements containing essential fatty acids may help decrease dry eye symptoms in some people. Ask your optometrist if the use of dietary supplements could be of help for your dry eye problems.
Avoiding becoming dehydrated by drinking plenty of water (8 to 10 glasses) each day.
Keratoconus is a vision disorder that occurs when the normally round cornea (the front part of the eye) becomes thin and irregular (cone) shaped. This abnormal shape prevents the light entering the eye from being focused correctly on the retina and causes distortion of vision.
In its earliest stages, keratoconus causes slight blurring and distortion of vision and increased sensitivity to glare and light. These symptoms usually appear in the late teens or late 20s. Keratoconus may progress for 10-20 years and then slow in its progression. Each eye may be affected differently. As keratoconus progresses, the cornea bulges more and vision may become more distorted. In a small number of cases, the cornea will swell and cause a sudden and significant decrease in vision.
The swelling occurs when the strain of the cornea’s protruding cone-like shape causes a tiny crack to develop. The swelling may last for weeks or months as the crack heals and is gradually replaced by scar tissue. If this sudden swelling does occur, your doctor can prescribe eyedrops for temporary relief, but there are no medicines that can prevent the disorder from progressing.
Eyeglasses or soft contact lenses may be used to correct the mild nearsightedness and astigmatism that is caused by the early stages for keratoconus. As the disorder progresses and cornea continues to thin and change shape, rigid gas permeable contact lenses can be prescribed to correct vision adequately. In most cases, this is adequate. The contact lenses must be carefully fitted, and frequent checkups and lens changes may be needed to achieve and maintain good vision.
In a few cases, a corneal transplant is necessary. However, even after a corneal transplant, eyeglasses or contact lenses are often still needed to correct vision.
Age-Related Macular Degeneration (AMD)
Symptoms of AMD
- Gradual loss of ability to see objects clearly
- Objects appear distorted in shape. Straight lines look wavy or crooked.
- Loss of clear color vision
- A dark or empty area appears in the center of vision.
Diagnosis of AMD
In its early stages, signs of macular degeneration can go unnoticed. Yet, if you experience any signs/symptoms, contact your doctor of optometry immediately. In a comprehensive eye exam, your optometrist will perform a variety of tests to determine if you have macular degeneration, or any other eye health problems.
Treatment of AMD
With “dry” macular degeneration, the tissue of the macula gradually becomes thin and stops functioning properly. There is no cure for dry AMD, and any loss in central vision cannot be restored. However, doctors now believe there is a link between nutrition and the progression of dry AMD. Dietary changes favoring low-fat content and dark green leafy vegetables can slow vision loss. Nutritional supplements also may be beneficial.
Less common, “wet” macular degeneration results when fluids leak from newly formed blood vessels under the macula and blur central vision. Vision loss can be rapid and severe. If detected early, “wet” AMD can be treated with laser treatment, which is often called photocoagulation. A highly focused beam of light seals the leaking blood vessels that damage the macula. Photodynamic Therapy (PDT) uses a medication injected into the bloodstream, which is then activated with a laser shone into the eye. A new therapy available, where a medication is injected into the back of the eye, is showing favorable results. These are not permanent cures but are used to slow the rate of central vision loss.
Age-Related Macular Degeneration (AMD) is the leading cause of severe vision loss in adults over age 50. The Centers for Disease Control and Prevention estimate that 1.8 million people have AMD and another 7.3 million are at substantial risk for vision loss from AMD. Caucasians are at higher risk for developing AMD than other races. Women also develop AMD at an earlier age than men. This eye disease occurs when there are changes to the macula, a small portion of the retina that is located on the inside back layer of the eye. AMD is a loss of central vision that can occur in two forms: “dry” or atrophic and “wet” or exudative.
Most people with macular degeneration have the dry form, for which there is no known treatment. The less common wet form may respond to laser procedures, if diagnosed and treated early.
Some common symptoms are: a gradual loss of ability to see objects clearly, distorted vision, a gradual loss of color vision, and a dark or empty area appearing in the center of vision. If you experience any of these, contact your doctor of optometry immediately for a comprehensive examination. Central vision that is lost to macular degeneration cannot be restored. However, low vision devices, such as telescopic and microscopic lenses, can be prescribed to maximize existing vision.
Researchers have linked eye-friendly nutrients such as lutein/zeaxanthin, vitamin C, vitamin E, and zinc to reducing the risk of certain eye diseases, including macular degeneration. For more information on the importance of good nutrition and eye health, please see the diet and nutrition section.
Ocular hypertension is an increase in the pressure in your eyes that is above the range considered normal with no detectable changes in vision or damage to the structure of your eyes. The term is used to distinguish people with elevated pressure from those with glaucoma, a serious eye disease that causes damage to the optic nerve and vision loss.
Ocular hypertension can occur in people of all ages, but it occurs more frequently in African Americans, those over age 40 and those with family histories of ocular hypertension and/or glaucoma. It is also more common in those who are very nearsighted or who have diabetes.
Ocular hypertension has no noticeable signs or symptoms. Your doctor of optometry can check the pressure in your eyes with an instrument called a tonometer and can examine the inner structures of your eyes to assess your overall eye health.
Not all people with ocular hypertension will develop glaucoma. However, there is an increased risk of glaucoma among those with ocular hypertension, so regular comprehensive optometric examinations are essential to your overall eye health.
There is no cure for ocular hypertension, however, careful monitoring and treatment, when indicated, can decrease the risk of damage to your eyes.
Presbyopia is a vision condition in which the crystalline lens of your eye loses its flexibility, which makes it difficult for you to focus on close objects.
Presbyopia may seem to occur suddenly, but the actual loss of flexibility takes place over a number of years. Presbyopia usually becomes noticeable in the early to mid-40s. Presbyopia is a natural part of the aging process of the eye. It is not a disease, and it cannot be prevented.
Some signs of presbyopia include the tendency to hold reading materials at arm’s length, blurred vision at normal reading distance and eye fatigue along with headaches when doing close work. A comprehensive optometric examination will include testing for presbyopia.
To help you compensate for presbyopia, your optometrist can prescribe reading glasses, bifocals, trifocals or contact lenses. Because presbyopia can complicate other common vision conditions like nearsightedness, farsightedness and astigmatism, your optometrist will determine the specific lenses to allow you to see clearly and comfortably. You may only need to wear your glasses for close work like reading, but you may find that wearing them all the time is more convenient and beneficial for your vision needs.
Because the effects of presbyopia continue to change the ability of the crystalline lens to focus properly, periodic changes in your eyewear may be necessary to maintain clear and comfortable vision.