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Vision Diseases, Disorders & Definitions

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M Definitions

Macula:

Small central area of the retina surrounding the fovea; area of well-resolved, acute central vision.

macular hole:

Retinal diseases in which central vision is lost. Age-related type (AMD) or age related macular degeneration is very common and affects people over 60. Juvenile macular diseases are hereditary; they include Stargardt's disease and Best's vitelliform macular dystrophy.

Macular Hole

Other Names Macular cyst, retinal hole, retinal tear, and retinal perforation.

What is a macular hole? A macular hole is a small break in the macula, located in the center of the eye's light-sensitive tissue called the retina. The macula provides the sharp, central vision we need for reading, driving, and seeing fine detail.

A macular hole can cause blurred and distorted central vision. Macular holes are related to aging and usually occur in people over age 60.

Macula Image
Image Courtesy: National Eye Institute, National Institutes of Health

Is a macular hole the same as age-related macular degeneration? No. Macular holes and age-related macular degeneration are two separate and distinct conditions, although the symptoms for each are similar. Both conditions are common in people 60 and over. An eye care professional will know the difference.

What causes a macular hole? Most of the eye's interior is filled with vitreous, a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape. The vitreous contains millions of fine fibers that are attached to the surface of the retina. As we age, the vitreous slowly shrinks and pulls away from the retinal surface. Natural fluids fill the area where the vitreous has contracted. This is normal. In most cases, there are no adverse effects. Some patients may experience a small increase in floaters, which are little "cobwebs" or specks that seem to float about in your field of vision.

However, if the vitreous is firmly attached to the retina when it pulls away, it can tear the retina and create a macular hole. Also, once the vitreous has pulled away from the surface of the retina, some of the fibers can remain on the retinal surface and can contract. This increases tension on the retina and can lead to a macular hole. In either case, the fluid that has replaced the shrunken vitreous can then seep through the hole onto the macula, blurring and distorting central vision.

Macular holes can also occur from eye disorders, such as high myopia (nearsightedness), macular pucker, and retinal detachment; eye disease, such diabetic retinopathy and Best's disease; and injury to the eye.

What are the symptoms of a macular hole? Macular holes often begin gradually. In the early stage of a macular hole, people may notice a slight distortion or blurriness in their straight-ahead vision. Straight lines or objects can begin to look bent or wavy. Reading and performing other routine tasks with the affected eye become difficult.

Are there different types of a macular hole? Yes. There are three stages to a macular hole:

  • Foveal detachments (Stage I). Without treatment, about half of Stage I macular holes will progress.
  • Partial-thickness holes (Stage II). Without treatment, about 70 percent of Stage II macular holes will progress.
  • Full-thickness holes (Stage III).

The size of the hole and its location on the retina determine how much it will affect a person's vision. When a Stage III macular hole develops, most central and detailed vision can be lost. If left untreated, a macular hole can lead to a detached retina, a sight-threatening condition that should receive immediate medical attention.

Learn more about Macular Holes

Macular Pucker

Other Names Epiretinal membrane, preretinal membrane, cellophane maculopathy, retina wrinkle, surface wrinkling retinopathy, premacular fibrosis, and internal limiting membrane disease.

What is a macular pucker? A macular pucker is scar tissue that has formed on the eye's macula, located in the center of the eye's light-sensitive tissue called the retina. The macula provides the sharp, central vision we need for reading, driving, and seeing fine detail. A macular pucker can cause blurred and distorted central vision.

Most of the eye's interior is filled with vitreous, a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape. The vitreous contains millions of fine fibers that are attached to the surface of the retina. As we age, the vitreous slowly shrinks and pulls away from the retinal surface. This is called a vitreous detachment, and is normal. In most cases, there are no adverse effects, except for a small increase in floaters, which are little "cobwebs" or specks that seem to float about in your field of vision.

However, sometimes when the vitreous pulls away from the retina, there is microscopic damage to the retina's surface (Note: This is not a macular hole). When this happens, the retina begins a healing process to the damaged area and forms scar tissue, or an epiretinal membrane, on the surface of the retina. This scar tissue is firmly attached to the retina surface. When the scar tissue contracts, it causes the retina to wrinkle, or pucker, usually without any effect on central vision. However, if the scar tissue has formed over the macula, our sharp, central vision becomes blurred and distorted.

What causes a macular pucker? Most macular puckers are related to vitreous detachment, which usually occurs in people over age 50. As you age, you are at increased risk for macular pucker.

A macular pucker can also be triggered by certain eye diseases and disorders, such as a detached retina and inflammation of the eye (uveitis). Also, people with diabetes sometimes develop an eye disease called diabetic retinopathy, which can cause a macular pucker. A macular pucker can also be caused by trauma from either surgery or an eye injury.

What are the symptoms of a macular pucker? Vision loss from a macular pucker can vary from no loss to severe loss, although severe vision loss is uncommon. People with a macular pucker may notice that their vision is blurry or mildly distorted, and straight lines can appear wavy. They may have difficulty in seeing fine detail and reading small print. There may be a gray area in the center of your vision, or perhaps even a blind spot.

Is a macular pucker the same as age-related macular degeneration? No. A macular pucker and age-related macular degeneration are two separate and distinct conditions, although the symptoms for each are similar. An eye care professional will know the difference.

Can macular pucker get worse? For most people, vision remains stable and does not get progressively worse. Usually macular pucker affects one eye, although it may affect the other eye later.

Is a macular pucker similar to a macular hole? A macular pucker and a macular hole are different conditions, although they both result from the same reason: The pulling on the retina from a shrinking vitreous. When the "pulling" causes microscopic damage, the retina can heal itself; scar tissue, or a macular pucker, can be the result. If the shrinking vitreous pulls too hard, it can tear the retina, creating a macular hole, which is more serious. Both conditions have similar symptoms - distorted and blurred vision. Also, a macular pucker will not "develop" into a macular hole. An eye care professional will know the difference.

Learn more about Macular Puckers

Medically Necessary Contact Lenses:

Medically Necessary contact lenses are provided only under certain medical conditions. These medical conditions prevent the member from achieving a specified level of visual acuity (performance) through the wearing of conventional eyeglasses. These contact lenses must be specifically prescribed by the eye doctor to be used for the reason or reasons described below. Reimbursement for these lenses will be considered as payment-in-full when utilizing a network provider.

  • Aphakia. A pair of prescription single vision or multifocal eyeglass lenses and an eyeframe can be provided along with contact lenses prescribed for this reason.
  • When visual acuity cannot be corrected to 20/70 in the better eye except through the use of contact lenses (must be 20/60 or better).
  • Anisometropia of 4.0 diopters or more, provided visual acuity (performance) improves to 20/60 or better in the weak eye.
  • Keratoconus. The narrowing of visual fields due to high minus or plus corrections is not considered a reason for medically necessary contact lenses. All requests for medically necessary contact lenses must be reviewed and approved by the Medical Advisory Board.

Microphthalmia

Other Names Anophthalmos and microphthalmos, small eye syndrome.

What are anophthalmia and microphthalmia? Anophthalmia and microphthalmia are often used interchangeably. Microphthalmia is a disorder in which one or both eyes are abnormally small, while anophthalmia is the absence of one or both eyes. These rare disorders develop during pregnancy and can be associated with other birth defects.

What causes anophthalmia and microphthalmia? Causes of these conditions may include genetic mutations and abnormal chromosomes. Researchers also believe that environmental factors, such as exposure to X-rays, chemicals, drugs, pesticides, toxins, radiation, or viruses, increase the risk of anophthalmia and microphthalmia, but research is not conclusive. Sometimes the cause in an individual patient cannot be determined.

Learn more about Anophthalmia and Microphthalmia

Minus (-) Lens:

Concave lens, stimulates focusing and diverges light. The lens is thinner in the center than the edges. It is used in glasses or contact lenses for people who are nearsighted (myopia).

Myopia, nearsightedness:

Focusing defect in which the eye has too much optical power. Light rays coming from a distant object are brought into focus before reaching the retina. Requires a minus lens correction to "weaken" the eye optically and permit distance vision.


References

Portions of this page are excerpted from Dictionary of Eye Terminology, copyright 1990-2006 by Barbara Cassin and Triad Communications. Reprinted with permission.

Some of the information above is reprinted from the National Eye Institute, National Institutes of Health, and is for educational purposes only. Superior Vision strongly recommends eye exams as the best way to diagnose eye conditions and learn more about potential vision problems.