Anatomy of the Eye
Macular degeneration
Diabetic retinopathy
Inherited retinal diseases
Retinitis Pigmentosa
Stargardt Macular Dystrophy
Low vision services
Community Resources

Anatomy of the Eye

Ever wonder how do your eyes see?

Old fashioned film cameras were created to mimic how we see, the only difference is they recorded the picture on a piece of paper and we record these images in our heads. Your eyes work just like a camera. The surface of the eye called the cornea is just like a camera lens, both focus on the incoming light to create an image.

The retina is a thin layer of nerve tissue much like camera film and it is light sensitive and located in the back of the eye. The rod and cone cells in the retina transform the rays of light into electrical signals.These electrical signals generated in the retina, are transmitted through the optic nerve to the brain where images are formed and interpreted. The center of the retina is called the macula. This is where the light focuses and it is the area that is responsible for sharp vision and small details like reading.

Multiple diseases affect different parts of the eye and cause decreased vision. For example, when people talk about cataracts, it is an example of a disease that is caused by cloudiness of the natural lens. Cataracts can be treated with surgery which will improve the person’s vision.

There are a myriad of diseases which affect the retina. Some of these retinal diseases are:

Macular Degeneration

Macular degeneration has multiple contributing causes:

• Age
• Smoking 
• Family history of macular degeneration. 

Macular degeneration occurs when small deposits accumulate in the macula and cause mildly blurred vision.

There are two forms of macular degeneration that can cause severe vision loss.

            1. Wet macular degeneration is the condition when blood vessels form in the center of the retina and cause reduced vision.

            2. Dry macular degeneration or geographic atrophy is when areas of degeneration enlarge over time, which can contribute loss of the central vision. The disease causes loss of patches of cells that  eventually turn into blind spots. If these spots grow into the center of the vision, the person afflicted will have a hard time reading.

Treatment:

Wet macular degeneration can be treated with injection of a medication into the eye to reduce leakage of the blood vessels. The goal of the treatment is to improve and stabilize the vision.

In the past Macular Laser Treatment used to be the standard treatment, however, studies have shown that it is less effective than an injection of medication into the eye.

There are multiple medications that are affective in reducing the leakage of the retinal vessels. The most commonly used medications for wet macular degeneration are Avastin (bevacizumab), Lucentis (ranibizumab), Eylea (aflibercept), and Vabysmo (faricimab).

Diabetic Retinopathy

One of the potential side effects of uncontrolled diabetes, with the person having elevated blood sugar for an extended time, can be diabetic retinopathy. If this occurs, the blood vessels in the retina start to leak and bleed.

Swelling of the center of the retina is called diabetic macular edema and can result in blurred vision. Abnormal retinal vessels then bleed into the eye, and cause visible floaters, otherwise known as dark spots in the vision that move around. This can lead to reduced vision. 

Additionally, growth of new retinal vessels can pull off the retina from the eye wall and cause a retinal detachment and severe vision loss.

Treatment: There are several treatment options for diabetic retinopathy.

1. Injections into the eye decrease retinal swelling, growth and leakage of the retinal vessels. Avastin (bevacizumab), Lucentis (ranibizumab), Eylea (aflibercept), and Vabysmo (faricimab) can be used.  2. Diabetic retinopathy with inflammation can be treated with steroids including Triesence (triamcinolone), Ozurdex (dexamethasone), and Iluvien (fluorocinolone). 

3. Laser of the macula and peripheral retina can reduce swelling and growth of retinal blood vessels. In severe cases diabetic retinopathy, retinal surgery is the best treatment.

Inherited Retinal Diseases

Retinal diseases that are caused by defects in a single gene are called inherited retinal disease. These conditions can sometimes be passed on from one generation to the next. There are over 300 different genes that can cause retinal disease.

Some genes can cause a similar disease appearance with retinitis pigmentosa as an example. In other cases, one single gene can have a different disease process depending on which defect is present in the gene.

A genetic defect is called a mutation. Some inherited retinal disease start early in life and other cause decreased vision with time. Certain condition cause decreased night vision and constricted peripheral visual field, and other conditions cause reduced central vision. There are several groups of inherited retinal diseases.

Retinitis Pigmentosa

Inside your eye, there’s an area called the retina and it’s job is to help you see things clearly. The retina has special cells called rods and cones. Rods help you see in a dim or darker light, and cones help you see colors and details.

So if your eye is like a puzzle, and the pieces of the puzzle are tiny cells in your retina. These cells are what help you to see. In Retinitis Pigmentosa, these puzzle pieces start to break and change and as these puzzle pieces change, it’s similar to having parts of a jigsaw that don’t fit together anymore.

The outcome is when you look at something, some parts of the picture might be missing or not clear. It’s like trying to complete a puzzle with some pieces that are broken or lost.

People afflicted with Retinitis Pigmentosa might notice that their vision gets worse over time. They might have trouble seeing in the dark or in dimly lit places. Their side vision may also become narrower, like looking through a tunnel.

Stargardt Macular Dystrophy

Imagine that your eye is a camera that takes photos of everything you see. Inside of it, there’s a special part called the retina and it is similar to the film in the camera. The retina’s job is to help a person see clearly.

The macula is like the center of the camera’s film, and it helps you see details, like when you’re reading a book or looking at someone’s face. But in Stargardt macular dystrophy, something is not working properly with the macula. It’s similar to if the film in a camera got messed up, and the pictures turned out blurry or dark.

People with Stargardt macular dystrophy might have trouble seeing things in the center of their vision, but they can still see things on the sides. It’s kind of like having a smudged spot in the middle of your picture.

Stargardt macular dystrophy is something you’re born with, and it usually happens when a special part of your eye doesn’t work right. There’s no cure for it yet, but researchers are hoping to find a cure and to find ways to help people with this disease see better.

Low Vision Services

Community Resources

Resources for People with Reduced Vision

View Finder : Low Vision Resource Finder

A low vision optometry practice offering comprehensive low vision evaluation.

Foundation for Blind Children: Low Vision Clinic

A school for children with low vision that also provides low vision evaluation and training for children and adults.

Midwestern University Clinics: Low Vision Rehabilitation

An optometry training program with a low vision clinic that includes training for low vision devices and technologies.

Desert Low Vision Services

A low vision optometry practice that provides evaluation and training for people with vision impairment in Southern Arizona.

Vocational Rehabilitation

Arizona Department of Economic Security offers rehabilitation services and job training for people with vision-related disability.

Arizona Industries for the Blind

A non profit organization providing professional training and employment for visually impaired individuals throughout Arizona.