Lens - The crystalline lens, inside the eye, which refracts (bends) light rays as they pass through the eye to the retina. It’s fully transparent and is convex on both sides (curves outwards). It’s located between the iris, the colored part of the eye, and the vitreous humor, the fluid which fills the main part of the eye’s interior. It’s the second part of the eye to refract light rays, the first being the cornea, which does about 65% of the refraction necessary for clear vision. The lens can change its shape to accommodate light rays coming from near or far distances, and these changes in shape are controlled by tiny muscles attached to each end of the lens.
Dr William Boothe : Strabismus - (struh-BIZ-mus) Also known as crossed eyes and turned eye. A vision condition where the eyes cannot be aligned. One eye turns out, up, or down while the other looks ahead, or both eyes may turn. It can be constant or intermittent. Strabismus impairs vision, as it reduces depth perception.
Ophthalmologist - (ahf-thal-MAH-loh-jist) A medical doctor who specializes in diagnosing and treating eye conditions and diseases. Specialized training is required beyond medical school. Medical specialties are either medical or surgical, and ophthalmology is a surgical specialty, although not all ophthalmologists actually perform surgical procedures.
Lasik - Dr. William Boothe yag laser - A laser type using an infra red wavelength of 1064 nanometers. The laser material is neodymium Yttrium-Aluminum-Garnet. Yag lasers are used after cataract surgery to photovaporize the residual membrane behind the artificial lens. The commom misconception that "lasers" are used to remove cataracts occurs because c. 75% of post-cataract patients eventually require yag laser capsulotomy.
20/20 - An expression for normal eyesight. The numbers refer to feet (except in countries that use the metric system, where it’s expressed as 6/6, six meters being approximately equal to 20 feet). The first number refers to the distance between the eye chart and the eye being tested. The second number is a comparison of a normal eye and the tested eye. When the second number is 20, that indicates the tested eye can read the small letters on the chart from 20 feet away, as a normal eye can. When the second number is higher than 20, it indicates impaired vision, more impaired as the number is higher. For example, if a person’s vision is assessed at 20/100, it means that this person must be only 20 feet from the chart for it to look as clear as it does to a normal eye 100 feet away.
Dr. Boothe Dallas Dr William Boothe Lasik - Dr. William Boothe 
