Types of Visual Impairments:

Eye Conditions

• Macular Degeneration: When the macula is damaged, the eye loses its ability to see detail, such as small print, facial features or small objects. The damaged parts of the macula often cause scotomas, or localized areas of vision loss. When you look at things with the damaged area, objects may seem to fade or disappear. Straight lines or edges may appear wavy.
  

• Cataracts: A cataract is a clouding of the lens of the eye.  The lens is a clear oval structure with three layers: the nucleus, the cortex, and the capsule. You have a cataract when the nucleus becomes opaque or when small opacities develop in the cortex that block or scatter light. 
  

• Glaucoma: is the term for a diverse group of eye diseases, all of which involve progressive damage to the optic nerve. Glaucoma is usually, accompanied by high intraocular fluid pressure. Optic nerve damage produces certain characteristic defects in the individual’s peripheral vision.
  

• AIDS-related vision loss: Cytomegalovirus retinitis, a member of the herpes virus family, produces an infection of the retina in immunocompromised individuals. 

• Corneal Pathology: Injury or damage to the cornea results in a distorted or clouded image and increased glare sensitivity.  Clear detail is no longer discernable, but the person's field of vision is normal.

• Diabetic Retinopathy: Leaking of retinal blood vessels may occur in advanced or long-term diabetes, this affects the macula or the entire retina and vitreous.  Not all people with diabetes develop retinal changes.

• Retinitus Pigmentosa - A congenital degeneration of the pigmented layer of the retina leads to a severe loss of peripheral vision.  Even though central vision may remain clear.

• Hemianopia: Damage to the optic pathways in the brain, which can result from acquired brain injuries due to stroke, tumor or trauma, can cause vision loss in half of the field.