Abstract
Abstract: :
Purpose: There are many reports of retinal and optic nerve toxicity caused by the use of retinoids. Documented side effects reported include night blindness, reduced colour vision and reduced visual acuity. As a result the British Civil Aviation Authority (CAA) and the European Joint Aviation Authorities (JAA) bar potential pilots who have taken isotretinoin (Accutane) from holding commercial pilots licences, whilst the U.S. Federal Aviation Administration requires them to undergo basic screening tests. In this study we assessed 42 young adults about to undergo military aircrew training who had a history of retinoid use with a view to evaluating the incidence of ocular toxicity. Methods: Forty two individuals (40 males, 2 females) (age range 19-28) with a history of retinoid use, underwent ocular electrophysiology (VEP, EOG, standard ERG), colour vision analysis, and Goldmann Weekers dark adaptation (DA) testing. These were compared to laboratory normals and 20 age/sex matched normal controls. Results: Forty-one of the patients having taken isotretinoin showed no abnormality in EOG, ERG, VEP, DA or colour vision. The groups mean scotopic ERG b wave amplitude was 423uV (S.D. 23) compared with 408uV (S.D. 49) amongst the controls. The group mean a to b ratio was 0.67 (S.D. 0.04) compared to 0.69 (S.D. 0.06) in the controls. Group mean DA final threshold was 10 1.8 compared to 10 2.1 in controls. One patient who had taken isoretinoin (Etretinate) had an abnormal ERG, impaired dark adaptation and reduced colour vision. Conclusions: These findings show that in 41 young individuals that had taken isotreinoin there was no evidence of retinal or optic nerve toxicity, or impaired dark adaptation. However one case did demonstrate that previous use of isoretinoin may cause permanent retinal toxicity and night blindness. This has important implications for applicants to be commercial or military pilots.
Keywords: drug toxicity/drug effects • electrophysiology: clinical • dark/light adaptation