IMPROVING SIGHT.

Source: JAMA 2001; 285:1008

Patients who are losing their vision due to degenerative eye diseases can be trained to see better using islands of the retina that are still functioning. Researchers at the University of Illinois at Chicago say rehabilitation begins with mapping the visual acuity of 27 discrete locations on the retina where functioning cells may be found mixed in among diseased areas. Precise measurements of the visual acuity at each location are taken using the system called functional microperimetry. A device attached to an ophthalmologist's slit lamp shows letters to the patient at different focal points on the retina. The data, which show which cells are functioning, are then recorded electronically, producing a 3-dimensional chart of each location's ability to resolve images. The data are then supplemented with an analysis of the potential longevity of the retinal cells. With data from both sets of noninvasive tests, researchers can identify areas of the retina that not only are capable of responding to light, but are l ikely to survive the ravages of a degenerative disease.