Cataract Awareness Month

Cataracts are one of the leading causes of blindness in the United States if not treated. The longer cataracts are left untreated the more difficult it can be to successfully remove the cataract and restore vision.

Cataracts are a clouding of the lens in the eye which prevents the passage of light into the eye. The lens helps focus images into the retina and vision may become blurry or dim because the cataract stopped the light from properly passing through.

Cataract surgery is the safest and most effective of surgeries. The surgery replaces your lens with an artificial lens called an intraocular lens. Most symptoms don’t show until the age of 40, however even young people and children can be affected. You can prevent cataracts by reducing exposure to UV rays, wearing proper eye protection to avoid eye injury and regular checkups at the eye doctor.


Schedule your appointment today to prevent blindness and treat cataracts.

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What is Hyperopia and what causes it?

63344-004-F2D7B516Hyperopia, also known as farsightedness, longsightedness or hypermetropia, is a defect of vision caused by an imperfection in the eye (often when the eyeball is too short or the lens cannot become round enough), causing difficulty focusing on near objects, and in extreme cases causing a sufferer to be unable to focus on objects at any distance. As an object moves toward the eye, the eye must increase its optical power to keep the image in focus on the retina. If the power of the cornea and lens is insufficient, as in hyperopia, the image will appear blurred. Hyperopia is often confused with presbyopia, another condition that frequently causes blurry near vision.

Presbyopes who report good far vision typically experience blurry near vision because of a reduced accommodative amplitude brought about by natural aging changes with the crystalline lens. It is also sometimes referred to as farsightedness, since in otherwise normally-sighted persons it makes it more difficult to focus on near objects than on far objects. The causes of hyperopia are typically genetic and involve an eye that is too short or a cornea that is too flat, so that images focus at a point behind the retina. People with hyperopia can usually see distant objects well, but have trouble focusing on nearby objects.

What is Presbyopia?

eye12_72_PresbyopiaREVPresbyopia is a condition where the eye exhibits a progressively diminished ability to focus on near objects with age. Presbyopia’s exact mechanisms are not known with certainty; the research evidence most strongly supports a loss of elasticity of the crystalline lens, although changes in the lens’s curvature from continual growth and loss of power of the ciliary muscles (the muscles that bend and straighten the lens) have also been postulated as its cause. Like gray hair and wrinkles, presbyopia is a symptom caused by the natural course of aging. The first signs of presbyopia–eyestrain, difficulty seeing in dim light, problems focusing on small objects and/or fine print–are usually first noticed between the ages of 40-50.

The ability to focus on near objects declines throughout life. In optics, the closest point at which an object can be brought into focus by the eye is called the eye’s near point. A standard near point distance of 25 cm is typically assumed in the design of optical instruments, and in characterizing optical devices such as magnifying glasses. Without correction, the near point is at 3 inches (7 cm) at age 10, to 6 inches (16 mm) at age 40, to 39 inches (1 meter) at age 60. As a result, a 60-year-old must use corrective lenses to read at a comfortable distance of 60 inches.

How High-Index Lenses Differ From Regular Lenses

M12-04 High Index LensesEyeglass lenses are able to correct vision because they bend light as it passes through the lens. The amount of light-bending (or refraction) that’s needed to provide good vision is determined by the eyeglass prescription provided by your eye doctor. For weaker eyes, the number in the prescription is higher, and the lenses must bend the light more to provide clear vision. Prescriptions for nearsighted people begin with a minus symbol (-). If your prescription is -5.00 diopters, for example, you are very nearsighted and need a stronger lens than someone with a -2.00 prescription.

To bend light more, stronger minus lenses require thicker edges than weaker minus lenses. It’s not unusual for a nearsighted prescription to worsen over time, which means the edges of your lenses will grow increasingly thicker with each prescription change. Fortunately, chemists have created a variety of new plastic lens materials such as 1.60-1.71 and higher these thinner lenses bend light more efficiently than the conventional plastic lenses used for eyeglasses. This means less material can be used in high-index lenses to correct the same amount of nearsightedness.

Anti-Reflective Coating

lens-coat-glare-660x330Anti-reflective coating (also called AR coating or anti-glare coating) improves both your vision through your lenses and the appearance of your glasses.AR coatings are similar to the coatings found on microscopes and camera lenses. They consist of several layers of metal oxides applied to the front and back lens surfaces. Because of the layering effect, AR coatings sometimes have a hint of green or purple color, depending on the individual manufacturer’s formula.Each layer is calculated to block reflected light. The result is that you’ll see a reduction in glare, annoying reflections and halos around lights. This is a great safety benefit when you’re driving at night. Anti-reflective coating benefits virtually everyone who wears eyeglasses. Also, research shows wearing AR coated lenses improves night driving vision and increases comfort during prolonged computer use (compared with wearing uncoated lenses).

AR coating is especially beneficial if you choose high-index lenses. These thinner, lighter lenses reflect more light than regular plastic lenses unless anti-reflective coating is applied. Anti-reflective coating is also beneficial when applied to the back surface of lenses in sunglasses, because it eliminates reflections of sunlight into your eyes from the lenses when the sun is behind you. (Since the purpose of sunglasses is to reduce how much light enters your eyes and because you aren’t concerned about making eye contact with others when wearing shades, there is no benefit to having AR coating applied to the front surface of sunglass lenses.)

What is Macular Degeneration?

image.axdMacular degeneration (or age-related macular degeneration, abbreviated AMD) is the leading cause of vision loss in the Western world. The disease affects the retina, the light-sensitive layer of tissue at the back of the eye. This layer has photo-receptors that are stimulated by light and send signals to your brain, thereby generating vision. Specifically, AMD affects the central part of the retina called the macula and this is the portion of your eye that is used when engaging in visual activities that require the finest acuities, such as reading and driving. Macular degeneration occurs in either a dry (atrophic) or wet (exudative) form. In either case, the disease only affects the central vision, typically near the macula, and rarely causes total vision loss.

Normal Macular Degeneration
The majority of patients (over 80% of AMD cases) have the dry or atrophic type of macular degeneration. In this form of the disease, the slow deterioration of the retina is coincidental with the formation of small yellow deposits, known as drusen, in the macular region. This accumulation of drusen leads to a thinning of the macular tissues, causing distortions in vision that initially appear as wavelike. The eventual amount of central vision loss is directly related to the location and amount of retinal thinning caused by the drusen.
The exudative, or wet form of the disease, is far less common (about 20% of AMD cases), but it is more aggressive and threatening to one’s vision. In the wet type of macular degeneration, abnormal blood vessels grow under the retina and macula through a process called neovascularization. These new blood vessels may bleed and leak fluid, thereby causing the macula to bulge or lift up, distorting or destroying central vision. In these circumstances, vision loss may be rapid and severe.
Although much research is being done on finding treatments for macular degeneration, no current treatment exists for the more common dry form, and the treatment for the wet form sometimes does not meet patients expectations. So, for many AMD patients, the use of low vision aids for macular degeneration is of great help and allows them to enhance their quality of life and remain independent.
What causes Macular Degeneration?
Parts of the eye
No one knows exactly what causes dry macular degeneration. But research indicates it may be related to a combination of heredity and environmental factors, including smoking and diet.
The condition develops as the eye ages. Dry macular degeneration affects the macula — an area of the retina that’s responsible for clear vision in your direct line of sight. Over time tissue in your macula may thin and break down.
Risk factors
Factors that may increase your risk of macular degeneration include:

  • Age. This disease is most common in people over 65.
  • Family history and genetics. This disease has a hereditary component. Researchers have identified several genes that are related to developing the condition.
  • Race. Macular degeneration is more common in whites than it is in other people.
  • Smoking. Smoking cigarettes or being regularly exposed to smoke significantly increases your risk of macular degeneration.
  • Obesity. Research indicates that being obese may increase your chance that early or intermediate macular degeneration will progress to the more severe form of the disease.
  • Cardiovascular disease. If you have had diseases that affected your heart and blood vessels, you may be at higher risk of macular degeneration.

Symptoms

Vision with macular degeneration

Dry macular degeneration symptoms usually develop gradually and without pain. They may include:

  • Visual distortions, such as straight lines seeming bent
  • Reduced central vision in one or both eyes
  • The need for brighter light when reading or doing close work
  • Increased difficulty adapting to low light levels, such as when entering a dimly lit restaurant
  • Increased blurriness of printed words
  • Decreased intensity or brightness of colors
  • Difficulty recognizing faces

Dry macular degeneration usually affects both eyes. If only one eye is affected, you may not notice any changes in your vision because your good eye may compensate for the weak eye. And the condition doesn’t affect side (peripheral) vision, so it rarely causes total blindness.
Dry macular degeneration is one of two types of age-related macular degeneration. It can progress to wet (neovascular) macular degeneration, which is characterized by blood vessels that grow under the retina and leak. The dry type is more common, but it usually progresses slowly (over years). The wet type is more likely to cause a relatively sudden change in vision resulting in serious vision loss.
Low-vision aids for macular degeneration
There are many devices specifically designed to help people with low vision function better. Different devices are available for different tasks. A trained professional can help you understand which device is best for accomplishing your particular needs. Training and practice are also important in order to become skilled at using any device.
Optical low-vision devices. Optical low-vision devices use lenses to magnify objects, making them easier to see. The lens strength will depend on your vision and the size of the object or print to be seen.
Magnifying spectacles. Which are stronger than ordinary glasses. They can be used for near tasks, such as reading, threading a needle, or any activity that requires detailed vision. The printed page or object must be held closer than usual in order to keep things in focus. One advantage of magnifying spectacles is that your hands remain free to hold reading materials or perform tasks.
Hand magnifiers. Familiar to most people and are available in varying strengths. Reading material is not necessarily held as close to the face as with magnifying spectacles, and some models come with a built-in light. High-quality and high-powered magnifiers are often available only in specialized stores or through vision rehabilitation professionals.
Stand magnifiers. Rest directly on the reading material, keeping the lens at the proper distance from the page. The ability to rest the magnifier on the page is useful for patients with a tremor or arthritis.
Telescopes. Used for seeing objects or reading signs that are far away. They can be handheld like a pair of regular binoculars or mounted on a pair of eyeglasses.
Video magnifiers. Electronic devices that use a camera and television screen to enlarge printed material, pictures, or small objects. They are adjustable and can enhance the material in different ways — for example, by making the print appear darker (increased contrast). The technology is developing rapidly, and electronic devices are becoming smaller, more portable and easier to use. Some can even be used for both distance and near tasks.

Other low-vision devices and techniques

There are numerous low vision aids, devices, and techniques to help make everyday activities easier, including:

  • Electronic books, e-book readers and audio books
  • Large-print books, newspapers, magazines, playing cards, and banking checks
  • High-contrast and large number telephones, thermostats, watches, and remote controls; talking watches, timers, books, and medical devices
  • Bold-tipped markers for easy-to-read shopping and phone number lists
  • Computers that can magnify (on screen or on paper) any printed material or picture, or that read aloud what is viewed on screen
  • Sitting closer to the television (this will not damage your eyes)

Lighting and glare
Good lighting and glare control are very important for people with low vision. A bright light should always be used when reading and its location should be adjusted for the greatest visibility without glare. Stronger light bulbs in darkly lit areas can make tasks like cooking, dressing, and walking up and down stairs easier. Wearing a hat with a wide brim or tinted wraparound sunglasses can shield your eyes from dazzling and annoying overhead lights or sunlight.

What is a Low Vision Specialist?
A Low Vision Rehabilitation Specialist is an optometrist or ophthalmologist who has been trained in Low Vision Rehabilitation. There are other professionals who specialize in specific aspects of low vision rehabilitation such as occupational therapists, orientation and mobility instructors. Low Vision Rehabilitation is available in most major medical centers and, in some cases, in private practices. Ask your retina specialist or eye doctor about referring you to a low vision specialist. See a Optometrist if you notice change in your central vision or your ability to see colors and fine detail becomes impaired. These changes may be the first indication of macular degeneration, particularly if you’re over age 50.

http://www.eschenbach.com/about-low-vision-macular-degeneration.htm

http://www.aao.org/eye-health/tips-prevention/amd-low-vision

http://www.brightfocus.org/macular/article/macular-low-vision-tips

http://www.mvrf.org/coping-with-macular-degeneration/faq-about-low-vision-specialists/

Why Do They Dilate my Eyes for an Eye Exam?

Pupil dilation is extremely important because it allows the optometrist to see all the way into the back of the eye. During a normal eye exam, the optometrist will use a bright light and a lens to look into the eye, inspecting the health of the cornea, iris, and lens of the eye. However, the bright light causes the pupil to contract, making it difficult for the optometrist to see the back of the eye. When the regular eye exam is done, the optometrist will dilate your pupils so that he or she can completely check your optical health.

The back of the eye hosts the retina, optic nerve, and important blood vessels. When your pupils are dilated, the optometrist will be able to clearly see these parts of the eye and evaluate them. Pupil dilation can reveal general health problems like diabetes, hypertension, and can also catch the signs of glaucoma and cataracts early. For these reasons, optometrists ask their patients to submit to pupil dilation with every eye exam, despite the inconvenience, because they would rather catch serious medical problems early. Healthy kids and adults should have an eye exam, along with pupil dilation, every one to two years, or more frequently as recommended by an optometrist. People who are at high risk for developing optical conditions may need to have their eyes examined more frequently.

How does Diabetes affect the eyes?

eye-woman-595x240Diabetes is a leading cause of blindness and visual impairment in the United States. A person with diabetes has 25 times the risk of blindness compared to a no diabetic person, and diabetic retinopathy (bleeding in the retina secondary to diabetes) is the leading cause of new blindness in Americans of working age.

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Why does a contact lens prescription expire in one year and an eyeglass prescription expire in two years

A contact lens prescription is good for only one year because the materials come in direct contact with the front of the eye, the cornea. The materials Contact-Lensescan alter the superficial cells of the cornea by decreasing oxygen to the tissue. This can contribute to complications such as corneal edema (swelling) and blood vessel growth around the periphery, strongly indicating a lack of oxygen to the tissue. Read more