Issue Date: VCPN May 2010 THE CHANGING LOW VISION PRACTICE Today’s high-tech instrumentation provides objective findings to assist in the management of vision loss. Bruce P. Rosenthal, OD, FAAO USOphthalmic’s Gilras GRK 7000 autorefractor/keratometer provides invaluable findings for low vision patients. The 21st century has been marked by increasing technology use in all areas of eyecare. Low vision clinicians are no exception and have been incorporating new technology to “co-manage” many of their patients who are undergoing treatment for conditions such as age-related macular degeneration (AMD), diabetic retinopathy, and glaucoma. In particular, autorefraction, high-resolution fundus photography, and OCT (optical coherence tomography) have been gaining greater acceptance with low vision clinicians when it comes to un-derstanding visual function as well as significant changes in the pathology that warrant immediate attention. The following case studies illustrate this point. AUTOREFRACTION Ocular findings of a patient aged 34 with tyrosinase negative albinism were typical of those individuals with albinism: high pendular nystagmus, transillumination of the iris, strabismus (alternating esotropia), and a high hyperopic astigmatic correction. The patient’s work demands are similar to those of most people today, requiring many hours at the computer. As a result, he experienced greater ocular fatigue at the end of the day. Binocularity was not a problem since he had high alternating esotropia. The correction he wore was OD +6.50 -3.25 x 5; OS +8.00 -4.00 x 180. Modern autorefractors can help obtain beneficial measurements for this patient. In addition to being able to measure even when anomalies exist, today’s systems can provide measurement despite corneal opacities or nystagmus. Findings from Topcon Medical Systems, Inc.’s RM-8900 Autorefractor for this particular patient revealed OD +7.50 -6.50 x 178 and +8.75 -4.00 x 4. The autoK feature of this unit is another useful measurement to have for low vision patients. Readings were 43.12/49.25 @ 180 in the right eye and 42.62/48.37 @ 178 in the left eye. The patient was very satisfied with the new distance, reading, and computer prescription that incorporated the large astigmatic change in the right eye. MICROPERIMETRY Also becoming an integral area of testing for low vision practices is microperimetry. It is used in conjunction with the pre- and post-testing of a patient’s reading speed following extensive training on the use of eccentric fixation. NIDEK Inc.’s MP-1 Mircroperimeter biofeedback instrumentation is specifically designed to treat patients with low vision. It is a fundus tracking perimeter that provides true retinal sensitivity data as well as a quantitative analysis of fixation location and stability. Measurement of abnormally high refractive error is important with patients having pathological myopia or aphakia and high cylinders. The objective refractometer mode of the RM-8900 ranges from spherical -22.00D to +22.00D; cylinder 0.00D to +/-10.00D; a minimum measureable pupil diameter of 2.0mm; cornea curvature radius of 5.00mm to 10.00mm. Another option that provides invaluable findings is USOph-thalmic’s Gilras GRK 7000 autorefractor/keratometer, which measures the highest ranges of refractive error. The data from this instrument gives the doctor a tremendous starting point in determining the refractive error and corneal integrity. Vertex distance can be set from 0mm to 15mm—critical for low vision patients. The GRK 7000 can also be modeled into the Gilras Digital Refraction system.