Low vision is a term for conditions that result in dramatically reduced sight that cannot be entirely corrected with conventional eyeglasses, contact lenses, medicines or surgery. Several eye diseases or conditions can cause low vision and legal blindness. These are the three most common causes of low vision:
Age Related Macular degeneration (AMD) is a completely painless disorder that affects the central area of the retina, which is the light-sensitive tissue lining the inside of the eye. Within the retina, the area responsible for sharp central vision (called the macula) deteriorates, causing blurred vision. This can cause a blind spot in the central area of vision, which leads to legal blindness and low vision. There are two types of macular degeneration – non-exudative (dry form) and exudative (wet form). The dry form usually progresses slowly, while the wet form causes more rapid and severe vision loss due to the growth of abnormal blood vessels under the macula that leak fluid and blood. The biggest risk factor for macular degeneration is age. Other risk factors include genetics, race, smoking, and high blood pressure.
Diabetic retinopathy is a diabetes complication that affects the eyes. High blood sugar levels cause damage to blood vessels in the retina. These blood vessels become weak and leak blood and other substances into the retina. This leads to a lack of oxygen to the retina and new small blood vessels grow (neovascularization) and damage the retina in an attempt to fulfill the oxygen demand. These new blood vessels break, scar and contract leading to retinal detachment. Fluid can also accumulate under the central vision area resulting in macular edema and loss of vision. At first, diabetic retinopathy may cause no symptoms or only mild vision problems. However, over time, it can severely damage the retina, leading to low vision. Anyone who has diabetes can develop diabetic retinopathy. The risk increases for those who have had diabetes longer, as well as those with poor blood sugar control, high blood pressure, elevated cholesterol and those who smoke.
Glaucoma is a disease that damages the optic nerve and nerve fiber layer. Most commonly, this occurs when fluid pressure builds up in the front part of the eye, damaging the optic nerve. There are four types of glaucoma: open-angle, normal tension, angle-closure, and secondary. There are many risk factors for glaucoma, but those over 40 who have a family history of glaucoma should always have regular eye exams to check for glaucoma. In addition, you could be at an increased risk if Dr. Kubota has noted that you have high eye pressure, a family history of glaucoma, thin corneas, thinning of the optic nerve or nerve fiber layer, or have had an eye injury. Finally, certain health problems can increase the risk of glaucoma, such as diabetes, low blood pressure, or poor blood circulation.
Even though age and genetics play a part, you may have noticed some common risk factors – diabetes, smoking, and high or low blood pressure, which are all within your control.
Here are the most important steps you can take to reduce your risk of low vision from macular degeneration, diabetic retinopathy and glaucoma.
Be aware of your family's health history
Get regular physicals
Move your body
Eat a healthy diet
Check out changes in vision with Dr. Kubota ASAP
Protect your eyes from the sun
Get your eyes checked every year
By understanding the diseases that cause low vision, you can take steps now to reduce modifiable risk factors or get an early diagnosis to preserve your eyesight.