An ophthalmologist is a physician who specializes in the care and treatment of the eye. The ophthalmologist provides a full spectrum of eye care including vision testing, prescribing eyeglasses, diagnosis and treatment of eye disease, and surgery. An ophthalmologist may be a medical doctor (M.D.) or doctor of osteopathy (D.O.). Ophthalmologists use specialized tools and instruments in the diagnosis and treatment of the eye.
The ophthalmoscope is one of the primary instruments used by the ophthalmologist. It is a hand-held device used to examine the interior of the eye. Using a light source, either included in the device or worn on a head band-by the examiner, a concave mirror reflects the light into the eye. The examiner looks through an aperture and is able to view the eye at a variety of magnifications and depths by using a rotating disc of lenses. The ophthalmoscope helps examine the cornea, aqueous, lens, vitreous and the retina. It is also a common tool used by physicians.
The retinoscope is a useful tool when working with children or patients with limited ability to communicate. It is a hand-held tool that the examiner uses to shine a beam of light focused directly on the retina. By moving the light vertically and horizontally the examiner observes the movement of the retina. Different lenses are placed in front of the eye until the movement stops.This information helps determine the lens power that provides the retina a clearly defined image.
The ophthalmologist frequently uses the results of the retinoscopy test as a starting point for the phoropter testing. The phoropter is generally used in conjunction with an eye chart. The chart contains random letters with each line becoming increasingly smaller. The phoropter is a fairly large device that has three rotating disks that contain a variety of lenses as well as colored filters. The patient looks through the machine while the examiner changes the lenses. The patient looks at the chart and is then asked, which choice is better.
Eye charts help measure visual acuity, or how well you see in the distance. The Snellen eye chart is the most commonly used. It has 1 rows of random capital letters. The row top has one letter and the following rows get progressively smaller.
Various versions of the eye chart are available for children or patients who do not know the alphabet. A Tumbling E chart uses the capital letter E facing various directions. The patient is asked if the "E" is facing up, down, right or left.