Visual Impairment and Blindness in the Senior Population Content written by: June Smith-Jeffries – FCLSA, NCLE, COT Content originally published in the Winter 2014 edition of The Eighth Line Table of Contents • Introduction • Age-related Macular Degeneration o Types of ARMD . Dry ARMD . Wet ARMD o 3 Stages of ARMD o ARMD Risk Factors o ARMD Prevention o ARMD Detection o ARMD Treatment • Glaucoma o Causes of Glaucoma o Glaucoma Risk Factors o Types of Glaucoma . Primary Open-Angle . Secondary Glaucoma . Angle Closure Glaucoma . Low-Tension or Normal Pressure Glaucoma . Ocular Hypertension . Congenital or Infantile Glaucoma • Measuring Intraocular Pressure • Testing for VF Defects • Conclusion • Post Test Introduction A study commissioned for the National Coalition for Vision Health in 2007 states that 278,000 Canadians are visually impaired and an additional 108,000 are legally blind. (Visual impairment is defined as difficulty seeing ordinary newsprint or clearly seeing the face of someone from a distance of four meters or 12 feet.) The chances of developing an irreversible, serious loss of vision are one in nine by age 65 and this figure increases as one ages. Current projections indicate that over the next twenty-five years with our aging population, these numbers will increase dramatically, 1 | Page perhaps even doubling. Dr. David K. Foot, a professor at the University of Toronto, predicts an epidemic of blindness and impaired vision as the members of the baby boom generation reach their 70’s. That time is close at hand. Opticians are often the first of the three O’s to see a patient who is having visual difficulties. As health care professionals we have a responsibility to recognize the signs of eye diseases, and particularly those that most affect our senior patients. The most common age-related eye diseases are macular degeneration, glaucoma, diabetic retinopathy and cataract. Age-related Macular Degeneration Age-related macular degeneration (ARMD) is the leading cause of irreversible vision loss in the western world. Recent surveys estimate that nearly 80,000 Canadians are currently affected with AMD and as Canadians age that number is growing at a rate of 10,000 per year. Two forms of this condition exist. Exudative ARMD is also known as neovascular or wet ARMD. This type is by far the most severe. Non-exudative ARMD, the most common form, is known as dry macular degeneration and it progresses more slowly than exudative ARMD. It is possible to have the disease in one eye only, or to have one eye with a later stage of ARMD than the other. Types of ARMD Dry ARMD This condition is an early stage of the disease and may result from the aging and thinning of macular tissues, deposits of pigment in the macula or a combination of the two. Dry macular degeneration is diagnosed when yellowish spots referred to a drusen begin to accumulate in and around the macula. It is believed these spots are deposits or debris from deteriorating tissue. Their presence alone does not indicate disease, but it may mean that the eye is at risk for developing the more debilitating wet form of ARMD. Symptoms of gradual central vision loss may occur with dry macular degeneration, but rarely is the loss of vision as severe as with wet ARMD. Over a period of years, this form of the disease can progress to late-stage geographic atrophy, a gradual deterioration of retinal cells, which also can cause severe vision loss. Currently, no FDA-approved treatments are available for dry macular degeneration, although a few now are in clinical trials. 2 | Page Wet ARMD Approximately ten percent of cases of dry ARMD progress to the more advanced and damaging form of the disease. In wet macular degeneration, new blood vessels grow beneath the retina and leak blood and fluid. This leakage causes permanent damage to light-sensitive retinal cells, which die off and create blind spots in central vision. Choroidal neovascularization (CNV) is the underlying process causing wet ARMD. Abnormal blood vessel growth in the retina is the body's misguided way of attempting to create a new network of blood vessels to supply more nutrients and oxygen to the eye's retina. Instead, the process creates scarring, leading to sometimes severe central vision loss. Central Vision Loss Wet macular degeneration falls into two categories: • Occult – This type occurs with new blood vessel growth beneath the retina. The vessels are not as pronounced and leakage is less evident in this form. This type usually produces less critical vision loss. • Classic - Blood vessel growth and scarring have very clear, delineated outlines that can be observed beneath the retina. This is referred to as classic choroidal neovascularization (CNV) and usually produces more damage, resulting in serious loss of vision. 3 Stages of ARMD There are three stages of ARMD defined, in part, by the size and number of drusen under the retina. 3 | Page • Early ARMD - Early ARMD is diagnosed by the presence of medium-sized drusen, which are about the width of an average human hair. People with early ARMD typically do not have any vision loss. • Intermediate ARMD. People with intermediate ARMD typically have large drusen, pigment changes in the retina, or both. These changes can only be detected during an eye exam. Intermediate ARMD may cause some vision loss, but most people do not experience any symptoms. • Late ARMD. In addition to drusen, people with late ARMD have vision loss from damage to the macula. There are two types of late ARMD: o Geographic atrophy in dry ARMD is caused by gradual breakdown of the light-sensitive cells in the macula that convey visual information to the brain, as well as interruption of the supporting tissue beneath the macula. o In neovascular wet ARMD, abnormal blood vessels grow underneath the retina. These vessels can leak fluid and blood, which may lead to swelling and damage of the macula. The damage may be rapid and severe, unlike the more gradual changes in geographic atrophy. It is possible to have both geographic atrophy and neovascular ARMD in the same eye and either condition can appear first. Not everyone with early ARMD will develop late ARMD. Approximately five percent of patients, who have early ARMD in one eye and no signs of ARMD in the other eye, will develop advanced ARMD within ten years. Approximately fourteen percent of patients who have early ARMD in both eyes will develop late ARMD in at least one eye after approximately ten years. ARMD Risk Factors Age is a major risk factor for ARMD. The disease is most likely to occur after age 60, but it can occur earlier. Other risk factors for ARMD include: • Smoking - Research shows that smoking doubles the risk of ARMD. • Family history - People with a family history of ARMD are at higher risk. • Race – The disease is more common among Caucasians than among most other ethnicities 4 | Page ARMD Prevention According to the National Eye Health Education Publication issued in the US, high-dose supplements of vitamins C and E, beta-carotene, and zinc can be effective in treating ARMD. These supplements have been shown to slow the rate of progressive vision loss over a 5-year period, but only when the condition is not extremely advanced. It also has been suggested that these supplements may lower the risk of developing ARMD. Two other nutritional supplements, lutein and zeaxanthin, have been shown to improve visual function in ARMD patients. Opticians cannot suggest over-the- counter supplements, but it is prudent to be aware of these and refer patients who develop signs of ARMD. This particular publication states that if these supplements were in widespread use for a period of five years among people who are at risk for the disease, vision loss could be prevented for many. A number of manufacturers offer these nutritional supplements. The label may refer to "AREDS" or "AREDS2." Modification of lifestyle may reduce the risk of developing ARMD. These changes include refraining from smoking, preventing high blood pressure, reducing body mass index, increasing intake of the carotenoids found in dark green leafy vegetables, and wearing sunglasses that block ultraviolet and high-energy radiation. An article recently published in the Journal of the American Geriatrics Society reported that moderate consumption of wine is associated with decreased odds of developing ARMD. In a controlled study of people ranging in age from 60 to 75, it was found that 4% of the wine drinkers had ARMD compared with 9% of people in the study who drank no alcohol at all. ARMD Detection Early detection of either type of ARMD is critical. The Amsler Grid is used to test for small central visual field defects and/or distortions of the visual field, in ARMD or glaucoma. These tests are available in tear off sheets and as magnets or can be downloaded from the CNIB website or from other online sources. Testing can easily be done in your practice and Amsler grids can be given to patients to use at home. The simplest way for a patient to use the device is to attach it to a wall or, if magnetized, to a refrigerator. Instruct patient to test each eye separately and to wear correction if correction is usually worn. Ask patients to report to you if they notice a blank spot in central vision or if any of the lines look distorted or wavy when they view the grid. In such a case, an immediate referral to either an optometrist or an ophthalmologist should be made. 5 | Page ARMD Treatment Until fairly recently, the treatment options for people with neovascular ARMD have been limited; however, the following are now being used.