Focus on Eyecare
GETTING A SECOND CHANCE
The temporary change in vision known as “second sight” occurs during early cataract development when those needing corrective lenses for distance vision or reading find that they can see fine without their glasses. In its earliest stages, a cataract may change the consistency of the eye lens to the point where there is an alteration in its focus of light rays. As a result, people who were farsighted may gradually become nearsighted, or (less commonly) vice versa. This tendency toward nearsightedness as a cataract develops is called a “myopic shift.” While it may have other causes, people who experience significant changes in their eyeglass prescriptions over a one- to two-year period should be checked for cataract development.
P.S. If you are already nearsighted, second sight will make you even more nearsighted.
REACHING A LOW POINT
If medications, store magnifiers, reading glasses, and/or surgery fail to improve vision that has been compromised by injury, disease, or congenital abnormality, vision rehabilitation can help those with “low vision” make the most of the vision they have left. Aside from recommending optical devices that help those with compromised vision see better, vision specialists assess which activities are most important to low-vision patients and help them further pursue them. This comprehensive approach includes evaluating response magnification and contrast enhancement, and assessing whether patients are better visual learners or auditory learners. On the basis of these assessments, low-vision specialists can prescribe talking devices, closed-circuit TVs with enlarged lettering, or telescopes that fit onto glasses.
P.S. Because many older individuals have inadequate or poorly positioned lighting in their homes, they may be sabotaging their ability to read and negotiate stairs safely.
DO YOU EXPERIENCE NIGHT BLINDNESS?
Despite its popular name, “night blindness” (nyctalopia) does not cause complete blindness. The inability to adapt to low-light conditions is the result of an underlying condition and may be accompanied by symptoms such as eye pain, blurry/cloudy vision, sensitivity to light, and/or difficulty seeing into the distance. An eye exam can help reveal the cause of night blindness, which may range from glaucoma, cataracts, and nearsightedness, to vitamin A deficiency and even retinitis pigmentosa (a group of retina-damaging eye diseases). Depending on the cause, treatment may include wearing specific types of glasses or contact lenses that can help support correct vision, or wearing sunglasses to protect the eyes from ultraviolet light, which can cause further eye damage.
P.S. If night blindness affects a driver’s ability to see, it is an important matter of safety that he or she undergo a comprehensive eye exam.
“Polarized” lenses eliminate reflected glare from water; snow; and shiny, man-made surfaces such as metal, mirrors, windshields, and glass. This glare-canceling ability makes polarized lenses beneficial for drivers, light-sensitive individuals, post-cataract surgery patients, and anyone wanting to see more clearly in bright-sun conditions. All it takes is for sunglasses (with or without prescriptions) to be treated with a special chemical that lines up its molecules in a particular pattern that blocks some of the light passing through the lens. Only the light rays that approach the wearer’s eyes vertically can fit through the openings created by the polarized pattern, while the lenses will block out all the horizontal light waves bouncing off water surfaces and automobile windshields.
P.S. Polarized lenses can also be treated with an anti-reflective coating that further enhances vision by decreasing reflections of the lenses themselves.
The body’s balance system relies on a constant process of position detection, feedback, and adjustment, using communication between the inner ear, eyes, muscles, joints, and the brain. It comes as no surprise, then, that vision loss has been linked with loss of balance and falls among elderly individuals. Moreover, research shows that nearly one-quarter of older patients who suffer hip fractures have failing eyesight that appears to impede their recovery. On the basis of this finding, it is suggested that elderly hip-fracture patients undergo a visual acuity test toward the beginning of their rehabilitation, and that eyeglasses be prescribed to improve visual acuity to the optimal extent. From a preventive standpoint, prescription eyeglasses may help avoid bone-breaking falls.
P.S. People with vision loss are almost twice as likely to experience multiple falls as those with normal vision.
CORRECTING AN ERROR
Along with nearsightedness or farsightedness, “astigmatism” is a common refractive error that is caused by an irregularly shaped cornea. Normally, corneas are spherical in shape, allowing light rays entering the eye to focus on one point on the retina. With astigmatism, a football-shaped cornea causes light rays to focus on two points on the retina. Very mild astigmatism may not even be noticeable, but mild to moderate astigmatism can cause eyestrain, headaches, and slightly blurred vision. While eyeglasses are primarily chosen to treat astigmatism, special “toric” soft contact lenses can be used in many cases. These donut-shaped lenses are weighted on the bottom so that they do not rotate, providing stability that enables them to correct vision along different axes.
P.S. The specific cause of astigmatism is unknown, but it can be hereditary and is usually present from birth. It can decrease or increase over time.
FITTING FRAMES TO FLATTER
Eyeglass frames should be chosen to flatter the face. With this in mind, select frames that contrast with your facial shape (such as a square style on a round face), and find a design that is as wide (from temple to temple) as the widest part of your jawline. If the bridge of your nose lacks definition, choose frames with a bold bridge. The top of your frames should fall just below your brow line. Once you have selected the frames, take steps to ensure their longevity. Always remove your glasses with both hands. (Using one hand will bend the frame out of shape.) After removing your glasses, rest them on the edge of the frame, not on the lenses.
P.S. In order for a lens prescription to be effective, the optical center of each lens must be positioned directly in front of each corresponding pupil.
BRINGING PRESCRIPTIONS INTO FOCUS
To understand your lens prescription, it helps to know that the refractive power of a lens is measured in “diopters” (D). One diopter is the lens strength required to focus parallel rays at a distance of one meter. It takes a total refractive power of about 60 diopters to focus light on a retina that sits 22.22 millimeters behind the eye’s refractive surface. If the focal point falls in front of the retina, the eye is “nearsighted.” If it falls behind the retina, it is “farsighted.” These refractive errors can be corrected with a concave (minus) lens to move the focal point further back in the nearsighted eye, or a convex (plus) lens to move the focal point forward in the farsighted eye.
P.S. Nearsighted people typically experience blurred vision when looking at objects that are far away. Farsighted people typically see things well when far away, but encounter blurring when looking at things close up.
EAT FISH FOR HEALTHY EYES
Fatty fish such as tuna, salmon, mackerel, herring, sardines, and lake trout contain omega-3 fatty acids, which are strongly linked with improved cardiovascular health. Another health benefit that may come from eating a fish-rich diet is healthier eyes. According to one study, women who consumed the most omega-3s from fish were found to be 40% less likely to develop “age-related macular degeneration” (AMD) than women with lower fish intake. Other research points to an association between eating fatty fish and a lower risk of “diabetic retinopathy,” which is a complication of diabetes that often causes blindness. There is also a study that reveals that women who consumed the most omega-3s from fish had a 17% lower risk of “dry eye.”
P.S. Researchers have found that omega-3 fats appear to improve function in the eyes’ Meibomian glands, which produce the oily part of tears.
WALKING TO PREVENT GLAUCOMA
What makes the vision-robbing disease known as “glaucoma” so potentially dangerous is that its symptoms don’t become obvious until the disease has progressed to the point where irreversible vision loss has already occurred and additional loss may be difficult to prevent. For this reason alone, glaucoma is often referred to as the “silent thief of sight.” With this in mind, it is highly recommended that a complete eye exam be conducted as often as necessary. In the meantime, research shows that one way to help prevent glaucoma is to exercise at moderate to vigorous intensity (such as brisk walking or jogging). The study revealed that the most physically active people have up to a 73% lower risk of developing glaucoma.
P.S. While glaucoma can affect anyone, it is more common in those with diabetes, in African Americans over the age of 40, and in all people aged 60 and over with a family history of the disease.
CAN YOU READ THE FINE PRINT?
Even older adults with no serious age-related eye disorders are likely to find that their vision is not as good as it once was. Beginning in their early- to mid-forties, most individuals experience difficulty reading small print despite the fact that their distance vision remains excellent. Over time, those with the near-universal eye condition known as “presbyopia” find their ability to read print becomes ever more difficult. They might find themselves squinting to read and holding reading matter at arm’s length in order to cope with blurriness. By the time they reach their 50s and 60s, most presbyopic individuals find that they need reading glasses. Prescription reading glasses ensure that the magnifying power needed for each eye is properly specified.
P.S. One symptom of presbyopia (the Greek word for “old vision”) is difficulty reading anything by dim light.
FRAMING YOUR EYES PROPERLY
In order for your eyeglasses to fit properly, they should be custom-fitted to your face so that they are comfortable and the lenses perform as intended. Glasses that slip down the bridge of the nose or otherwise move during wear will not deliver optimum vision. With this in mind, it is important that the “endpieces” at the widest part of the frame extend no further than the widest part of your face (at the temples). This aspect of fit is more important than the size of the lens. Beyond that, each eye should be centered in its corresponding lens up to 5 millimeters inside the lens center. Nose pads should rest comfortably on the sides of the nose.
P.S. Eyeglasses frames’ arms (known as “temples”) should extend straight back to your ears and only touch the side of your head just in front of your ears. The 45-degree “temple tip” should rest comfortably but firmly at the top of the ear.
Concussion/ Vision Therapy
Vision therapy after a concussion is a series of in-office and at-home activities and exercises designed to improve the visual skills. As is typical with any type of rehabilitation following a brain injury, the outcome can sometimes be difficult to predict.
If you need glasses for distance viewing and reading, as well as any distance in between, you might want to have a look at “progressive lenses.” These lenses have the advantage of not having a telltale line between prescriptions as do bifocals. If necessary, a third prescription can be introduced in between for middle distance, creating trifocals. Without any line between prescriptive strengths, progressives provide smooth, continuous vision at near, middle, and distant focal ranges, with no unsettling image jumps. As a result, corrected vision provides more natural vision than bifocals or trifocals. While progressive lenses may require a period of adjustment, wearers often find that their utility and cosmetic appeal make an unbeatable combination. While eyeglass lenses are prescribed to correct all kinds of vision problems, prescription lenses have come a long way—offering you the opportunity to truly customize your eyeglasses and make a statement about how you choose to look at the world.
P.S. “Presbyopia” (the loss of focusing power
associated with middle age) is responsible for the need
for reading glasses.
WHAT DETERMINES EYE COLOR?
Even though our irises can range in color from dark to light brown, green, hazel, gray, and blue, there are actually only two different pigments in our eyes, brown and red. The iris, composed of connective tissue and a thin muscle that allows it to open and close in response to light, contains cells (melanocytes) that can make two different types of pigment, brown-black “eumelanin” and red “pheomelanin.” While dark eyes have the most pigment (particularly brown-black eumelanin), light blue eyes have the least amount of pigment; however, there is no blue pigment. Blue eyes occur when the white collagen fibers in the connective tissue in the iris scatter light in a way that makes the iris look blue.
P.S. Eye colors between dark brown and light blue have varying amounts of pigment and areas without any pigment, which leads to the unique colors of green, hazel, and gray.
While it’s easy to understand that a “nearsighted” eye’s refractive error happens when it is too long (from front to back) and a “farsighted” eye is too short, “astigmatism” is less well understood. This type of refractive error occurs when the eye does not focus evenly. Instead of being perfectly round, an astigmatic eye is not evenly curved in all directions. This subtle difference in curvature tends to blur the images and makes them seem to be stretched out. For instance, when an astigmatic eye looks at a vehicle’s taillight, it will seem to throw off streams of light. An astigmatic prescription creates complementary curvature in the corrective lens that allows light to focus evenly on the retina.
P.S. An astigmatic cornea is shaped more like a football than a basketball.
If you have been wearing the same pair of eyeglass frames every day for longer than you can remember (much in the way that some people have not changed their hairstyle for a decade or more), look upon a new pair of frames as a way to enhance or change your appearance. A new pair of glasses has the potential to change the way that people look at you, and even change the way that you look at yourself. Try opting for tortoise shell frames for a slightly more conservative and academic appearance at work, then choose frames with a more casual image for leisure time. Frames are every bit as able to fit the moment as fit the face.
P.S. Fashion eyeglasses provide one of the easiest ways to give yourself an image overhaul.
Anyone over age 55 probably already owns a pair of reading glasses, while those who wear prescription eyeglasses also likely own a pair of bifocals or progressive lenses. Those who spend a lot of time outdoors may also want to invest in a pair of sunglasses that not only enable them to see at a distance, but also allow them to see up close. Combine these needs with the glare coming off water, sand, or snow, and you have the ingredients for sunglasses with polarized bifocal or progressive lenses. By relegating the reading segment of the glasses as far down as possible on the lenses, these lenses allow active individuals to comfortably set their eyes on the task at hand.
P.S. Whatever sport glasses you purchase, be sure to choose shatter-poof lenses (polycarbonate or Trivex) that will not compromise safety.