Abstract
Purpose: :
Bradyopsia is a newly discovered retinal disease. Patients have subnormal vision, problems in adjusting to bright lights and difficulties in seeing fast moving objects. The ERG typically shows a tenfold prolonged suppression time after stimulation(1). Recently, the causative mutation was identified in the RGS9 gene, involved in the deactivation of photoreceptor responses(2). We will present the clinical features and follow up of six patients with this rare disease.
Methods: :
Patients were diagnosed between 1973 and 2004 at our department. The mutation in the RGS9 gene in the six bradyopsia patients was confirmed at the Ocular Molecular Genetics Institute, Boston (MA), USA. Clinical data were retrospectively obtained from patient records. In 2003 all patients were invited for a follow–up examination, thus having a follow up in some of 30 years. Visual acuities were measured with a standard Snellen chart and in 2003 with an ETDRS chart at luminances of 30 to 1200 cd/m2. ERG’s were recorded conform the ISCEV protocol. Additionally, a double flash protocol was used to assess the course of response recovery. Furthermore, assessment of colour vision, visual fields, dark adaptation and standard ophthalmological examination were done.
Results: :
Patients showed a consistency of their symptoms and ERG recordings, but an extreme variation of VA between visits, probably due to variation in testing conditions. The low to subnormal VA typically increased by 2 to 3 lines with use of pinholes. Luminances increasing above 100 cd/m2 had a detrimental effect on the visual acuity. Dark–adaptation, colour tests, and fluoresceine angiography were normal. Visual field tests showed a minor central sensitivity loss in some. Funduscopy was without major abnormalities. No progressive changes were seen over time.
Conclusions: :
Patients with bradyopsia have specific symptoms. Typical in the examination is the subnormal acuity, improving with the use of pinhole. Diagnoses can be made on ERG examination. Our results suggest that bradyopsia is stationary over time. When needed, advice for adjustments in daily life or simple visual aids that reduce brightness should be given. 1. Kooijman AC et al. Doc Ophthalmol (1991); 78: 245–254
2. Nishiguchi KM. et al. Nature(2004); 427: 75–78
Keywords: retina • genetics • electroretinography: clinical