Common Conditions Causing Vision Loss
Macular degeneration, most commonly referred to as Age-Related Macular Degeneration (ARMD), affects either a portion or all of the macula (area of the retina responsible for central vision and “seeing” fine details). Consequently, the central vision area normally captured by that part of the macula becomes blurred or is possibly seen as a dark spot.
Two forms of ARMD exist:
1) Atrophic (DRY) ARMD—approximately 80% of AMD patients have the dry form. Quite simply, dry ARMD is the thinning of the macula causing visual “holes” or deficits to appear in central vision.
2) Exudative (WET) ARMD—In this less prevalent form of ARMD, fluid collects beneath the retina resulting in varying degrees of visual disturbance.
Diabetes causes disorders of the circulatory system which can modify the tiny blood vessels of the retina and make them very fragile.
There are three primary conditions of diabetic retinopathy:
1) Background Retinopathy—The blood vessels are the first tissue affected in this stage. Diabetic control is extremely important in delaying or minimizing any impact on vision.
2) Macular Edema—This condition occurs when the blood vessels leak fluid which collects in the macula (responsible for detailed vision). Diabetic macular edema is perhaps the most common cause of decreased vision for diabetics.
3) Proliferative retinopathy—In this stage of the disease a proliferation of new abnormal blood vessels begin growing on the surface of the retina or optic nerve. These vessels are prone to bleed and can cloud the vitreous with blood. If left untreated, this condition can lead to a partial or total vision loss.
Primarily age-related, glaucoma results when the optic nerve (the connection between the eye and the brain) is damaged from increased pressure in the eye. Usually, this is caused by a blockage in the normal outflow of the aqueous humor.
In a normal eye, constant pressure is maintained by the fluid leaving at the same rate at which it enters. When the rate of outflow is impeded, pressure builds and this can slowly cause damage to the optic nerve, which is most often irreversible.
Three common forms of glaucoma exist:
1) Chronic—Gradual and painless in nature, it is the most common.
2) Acute—Strikes suddenly and often painfully, it causes the cornea to become cloudy.
3) Congenital—Caused by the malformation of the drainage system to the eye prior to birth or in on infancy.
A vision problem may result when damage occurs to the visual system, anywhere behind the eye to the seeing part of the brain. Sometimes loss of eyesight stems not necessarily from eye damage, but rather the brain’s inability to interpret the information from the eye. Along with this type of loss, peripheral vision loss can result from a brain injury.
The lens is the clear structure behind the pupil which allows light to be focused on to the retina. Should the clear lens become cloudy, visual information passing through may be degraded resulting in a decrease in vision. Because cataracts are often directly related to normal aging, many doctors believe that everyone will develop cataracts if they live long enough.
A portion of the retina can detach from the back of the eye due to any number of unknown events that impact the eye. If the retina remains detached for a significant length of time, it can no longer function properly, resulting in the loss of varying amounts of vision. Depending on the area of retina detached, prompt surgery can minimize vision loss.
This disease is due to the degeneration of the retina’s photoreceptor cells which are needed for peripheral vision and vision in dim light. It is an inherited problem and often progressive in nature. It begins with a loss of peripheral vision and eventually can affect central vision. After many years, total blindness may occur.