5. What is the most common cause of low vision?
This depends upon which country this applies to and how low vision is defined. World wide low vision may result from condition in the front part of the eye such as the cornea related to trachoma and also cataracts. In the back part of the eye age related macular degeneration and complications of diabetes are frequent causes.

6. Can children get macular degeneration in the eye like adults?
Other than trauma, there are a variety of inherited eye conditions in children which can lead to change in the macula orthe "seeing part of the eye".

7. Can children get tumors involving the eye?
Although relatively rare, cancers or tumors may develop in the eye. Tumors of the retina of the eye, retinoblastoma, can occur in both hereditary and non hereditary forms and requires specialty care.

8. How often should I have my eyes examined?
There are many considerations for having an eye examination. An important consideration is that decreased vision may occur without pain. As such, for most people examinations in early childhood and adulthood should include general eye examinations. These intervals include by 6 months of age; at 3-4 years of age; by 1st grade, by 18-50 years every 1-2 years and greater then yearly if greater than 51 years of age and older. Keep in mind these are routine recommendations. For any sudden or notable change in vision that requires immediate attention one should consult their eye care provider or be evaluated in an emergency room. These are general principles only, and one should seek the advice of their eye care provider.

1. How long has PREF been in existence?
PREF was incorporated in Pennsylvania in 1984.

2. What is the difference between an optician and an ophthalmologist?

An ophthalmologists is a licensed physician specializing in the diagnosis and treatment of medical and surgical diseases of the eye. In addition, both opticians and ophthalmologists may undergo specialized training according to their interests.

3. Can I volunteer of make a contribution to PREF?
In most cases students with advanced degrees may spend time at PREF working on projects related to retinal or other eye conditions. Contributions can be made to PREF at the listed address.

4. What research has PREF funded?

Because PREF is classified by the Internal Revenue Service as a medical research foundation it does not confer advanced degrees nor does it fund outside research projects. Other organizations with different tax codes may fund research projects.


Thomas Alva Edison, another visual learner, was one of the greatest inventors of all time and was granted over 1,000 patents. He is known for his invention of the electric light bulb, but he also invented other common household or familiar items such as the phonograph player and motion picture devices. His inventions were adaptable to a large scale which also required business knowledge. In this regard, Edition was one of the original founders of the General Electric Company. The Edison Hotel in Sunbury, Pennsylvania is still in existence and was the first hotel to use one of Edison's devices for electricity.





What follows below are the most often asked questions about PREF and it's activities and functions, as well as questions about eye diseases as they relate to adults and children. We will be happy to answer any other questions you may have. In addition, many of these questions pertaining to children are answered in publications PREF publishes for children. See our Education section to learn more about Oppy and download the free publications in a PDF format.

9. Why don't the eyes of fish or birds collapse when they are deep under water or flying high above the earth?
Some eyes have an "armor plate" of cartilage within the eye which helps to maintain shape and pressure under unusual conditions of increased outside pressure.

10. Is it possible to have more than two eyes?
Yes. In some vertebrates, such as a lizard, a third eye or parietal eye, is present. This is a light sensitive organ which in man is represented by the pineal gland. The tissues in the two organs are similar.

Answers to these questions are not ment to be medical advice, but topics for learning. For questions regarding eye conditions you should consult your health care provider or other professional source.