ophthalmology

The Columbia Encyclopedia, 6th ed.

ophthalmology

ophthalmology (ŏf´thălmŏl´əjē), branch of medicine specializing in the anatomy, function and diseases of the eye. Ophthalmologists specialize in the medical and surgical treatment of eye disorders, vision measurements for glasses (refraction), eye muscle exercises (orthoptics), and the prevention of blindness and care of the blind. Some of the major causes of blindness in adults are cataract, glaucoma, diabetic retinopathy, senile macular degeneration, retinal detachment and opacities of the cornea. Cataract is the loss of transparency of the lens in the eye; it may follow injury, infection, or aging. Glaucoma occurs when the pressure inside the eye becomes so high that it damages the optic nerve. In diabetic retinopathy, blood cells and serum leak out of the blood vessels and damage the retina. Retinal detachment occurs when the retina is separated from the underlying choroid and sclera, the fibrous base of the eye. The most frequent causes of visual loss in childhood are trauma to the eye and amblyopia (lazy eye). The ability to adjust focus from far to near gradually decreases with age. Important developments in opthalmology include Allvar Gullstrand's slit-lamp (1911), which illuminates the interior of the eye with a beam of light; the tonometer, an instrument used to measure the fluid pressure in the eye; the opthalmometer, which measures the eye's dimensions, capacity, and refractive errors; and the laser, which can be used to perform precise, delicate operations on the human eye. Radial keratotomy alters the curvature of the cornea by means of thin knife incisions, changing the refractive power of the cornea so that people no longer need glasses. Similar procedures are also done using lasers and radio waves. Still in the experimental stages, transforming growth factor beta (TGF-beta) shows promise of use as a sort of "retinal glue" to save sight in cases where there is no other treatment available.

See historical study by G. Gorin (1982).

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