Elsa Zavoda: Hello, everyone. Thank you in advance for attending my presentation today. We are going to review eye diseases and conditions to get started. I do review these eye diseases and conditions in brevity. I ask that if you would like more detailed information about them to please do research on your own to obtain more information. I did not want to lose too much of our seminar time in speaking about the physiology of these diseases.
Causes of Visual Impairment
Some causes of visual impairment are shown in Figure 1.
Figure 1. Visual impairments.
Cataract
Cataract is one example, which causes a blurred, distorted vision, scattering of light rays, and decreased color and brightness.
Macular Degeneration
Macular degeneration causes central vision impairment with blurring and distortion. It prevents an individual from seeing colors and details, such as small print.
Diabetic Retinopathy
Diabetic retinopathy can create a myriad of symptoms. It can affect a person's ability to see centrally or peripherally.
Glaucoma
Glaucoma can cause central and peripheral visual field defects but is most notably known for causing peripheral visual field defects. In end-stage glaucoma, it can also cause central visual field loss.
Optic Neuropathy
Optic neuropathy can cause a sudden loss of vision.
Optic Neuritis
Optic neuritis is a sudden loss of vision as well, that can occur in an individual who has a neurological disorder, such as multiple sclerosis.
Stroke
Stroke can cause visual field defects affecting central and peripheral vision.
Trauma
Finally trauma can cause visual problems.
Examples
This is a picture of normal vision (Figure 2).
Figure 2. No visual impairment.
This is how this same picture would look to someone with cataracts (Figure 3).
Figure 2. Vision distorted by cataracts.
As you can see there is blurring, distortion, muting of colors, and a general haze. A simulation would be to put a plastic baggy up to your eyes. It would mimic what a cataract would be like.
Macular degeneration, or Stargardt's macular dystrophy, which is a juvenile form of macular degeneration, causes that central blurring and distortion that you are seeing here in the center of the picture. The peripheral area of the picture is clear, but centrally you are losing details (Figure 3).
Figure 3. Central blurring or distortion caused by Stargardt's macular dystrophy.
For example, in a social situation, perhaps you could not see someone's face or facial details.
This is an example of another more pronounced form of it where you are getting a distortion and a metamorphopsia where things are shifting (Figure 4).
