Part 1 of 2
This article originally appeared in the spring/summer issue of InSight Magazine, a publication of Bosma Enterprises.
The causes of blindness vary widely. In fact, two people with the same eye disease may have very different experiences and visual acuities. This article will explore common types of eye diseases. Each section also includes a graphic representation of the effects of the disease. Blindness isn’t a universal experience. For instance, only 30 percent of people who are visually impaired are totally blind. A large majority of people have some sort of usable vision.
Macular Degeneration
According to the American Macular Degeneration Foundation, this is the leading cause of vision loss. There are 10 million Americans with the disease. It causes a deterioration of the central part of retina. This is the part of our vision that is responsible for focusing our central vision and it controls key visual abilities like reading, driving and recognizing objects like faces.
There are two types of macular degeneration, wet and dry. The most common form is dry and is also known as age-related macular degeneration. It is caused by a breakdown of cells in the macula part of the retina.
The wet form is rare, only impacting about 10-15 percent of those with macular degeneration. It is the more advanced type of the disease. This form is caused when the underlying membrane of the retina grows and breaks. This disrupts oxygen flow through the retina and abnormal blood vessels start to grow. The vessels are fragile and break, causing bleeding and scarring, which disrupts a person’s vision.
Macular degeneration tends to cause a loss of central vision and color perception. People with macular degeneration may have distorted or fuzzy vision, with difficulty reading or recognizing faces.
There is no cure for macular degeneration, but there are treatments to attempt to minimize vision loss.
Diabetic Retinopathy
Diabetic retinopathy is the most common form of diabetic eye diseases and is most often caused by chronically high blood sugar from type 1 and 2 diabetes. This causes damage to tiny blood vessels in the retina. These blood vessels bleed or hemorrhage, which distorts vision.
Some of the symptoms a person may have are spots or dark strings floating in the visual field, blurred vision, loss of color vision, dark or empty areas of vision or eventually total vision loss. Vision loss from diabetic retinopathy is sometimes irreversible, but early detection is key and can reduce the risk of blindness by up to 95 percent. Controlling blood sugar is important, and additionally, there are several types of surgeries that may help with the effects of diabetic retinopathy.
Glaucoma
Glaucoma is a group of diseases that can damage the optic nerve leading to vision loss. According to the National Eye Institute (NEI), several studies on the impact of eye pressure have found that it is a major factor in damage to the optic nerve. Pressure builds when fluid around the front of the eye is not able to flow properly. Another risk factor in developing glaucoma is high blood pressure. Higher blood pressure can lead to damage of the optic nerve. At first, glaucoma can show no symptoms. Without treatment, people with glaucoma will slowly lose peripheral vision as if they are looking through a tunnel. Over time, it can lead to total blindness.
There are several tests that can be performed by your eye doctor to catch glaucoma early. This is important because vision loss from the disease can’t be restored. Early intervention can delay the progression of vision loss.
Retinitis Pigmentosa
Retinitis pigmentosa (RP) is an inherited disease that results from genetic mutations. These genes carry the instructions on creating photoreceptor cells located in the retina, also called rods and cones. When these cells are not created properly or are destroyed because of the mutated genes, vision loss occurs.
RP is considered a rare disease and, according to the NEI, occurs in about 1 in 4,000 people worldwide.
Symptoms often begin at a young age. It can start as light sensitivity or difficulty seeing in low light progressing to a loss of one’s visual field. However, the disease’s impact on a person varies greatly, as there are several types of mutations that can cause RP.
There are few treatments for RP. The NEI has found that vitamin A may help slow the progression of vision loss. Also, there is a promising prosthetic device that is implanted on the retina.
The Argus II sends electrical signals from glasses to the implanted device, which can restore some vision. Though this doesn’t restore normal vision, it has allowed patients to read large print and navigate without the use of a cane or dog guide.
Cataracts
A cataract is a clouding of the eye’s lens. Most cataracts are age-related. However, there are other diseases that may cause an early onset, including diabetic retinopathy. Cataracts are caused by a buildup of proteins around the lens. Over time, this buildup can grow larger and cloud the entire lens. The lens focuses light on the retina and, when a cataract is formed, can reduce the lens’ ability to focus and could be severe enough to blur vision. It may also discolor one’s vision.
The main treatment is surgery. This involves removing the clouded lens and replacing it with an artificial one.
Anthony Scott is the Communications Specialist for Bosma Enterprises, a company that provides employment training and placement and rehabilitation services for people who are blind or visually impaired.