Abstract
Abstract: :
Purpose: In glaucoma besides optic nerve damage, an early selective affection of magno cellular pathways is known. Aim of this study was to examine possible changes of ganglion cells using a photostress recovery test, which evaluates predominantly inner retinal layers. Methods: This study included 15 eyes of glaucoma patients with a mean age of 58.5±15.7 years (range: 37-88 years) and 43 eyes of normals with a mean age of 39.7±13.7 years (range: 23-69 years). The glaucoma group had a mean disc morphological glaucoma stadium of 2.53±0.85 (range: 1-4). For comparison with the glaucoma group a age matched control group including 13 eyes with a mean age of 58.1±8.7 years was set up. Recoverytime after a defined 5 second photostress was measured using the Kontrastometer BA4 (Company: BKG Medizintechnik, Germany), which has the capability to measure contrast sensitivity stepless. The subjective contrast threshold was determined first, followed by the photostress exposure. Time after light exposure untill recognition of subjective contrast threshold defined the recoverytime. Results: Recovery time of normals was 4.79±1.95 seconds (median: 4.67s; 1.67s-8.00s). It was significantly shorter (p=0.004) as recoverytime of glaucomas (7.72±3.15s; median: 6.67s; 5.0-16.3s). Significant prolongation of recoverytime could already be detected in the first glaucoma stage. Conclusions: Results point to a prolonged recoverytime due to glaucomatous damage, which can be detected already in early glaucoma stages. This may show the ability of a photostress recovery test to detect early glaucoma.
Keywords: ganglion cells • electrophysiology: clinical • neuro-ophthalmology: optic nerve