Abstract
Purpose: :
To analyze retinal structure and function associated with areas of normal and abnormal fundus autofluorescence (FAF) in patients with retinitis pigmentosa (RP).
Methods: :
Fifteen eyes of 15 patients with RP (autosomal dominant=5, Usher type II=3, autosomal recessive=7) aged 10-62 years, with visual acuities 20/20 to 20/40, were studied. Visual sensitivity in the central 10° was measured with the Humphrey Visual Field Analyzer (Zeiss), using the 10-2 program and with the MP-1 Microperimeter (Nidek Technologies). Fundus autofluorescence imaging (FAF) was performed with a confocal scanning laser ophthalmoscope (Heidelberg HRA II). The integrity of retinal layers in the central 10° was evaluated with spectral domain optical coherence tomography (Cirrus SD-OCT, Zeiss Meditec Inc). The thicknesses of the total receptor (Bruch’s membrane to the inner nuclear layer), and outer nuclear layer plus outer plexiform layer (ONL+) through the foveal region were measured using a computer-aided manual technique (1). Visual field sensitivities in the central 10° were compared to areas of abnormal FAF and to thicknesses of the underlying retinal layers in corresponding retinal areas.
Results: :
All 15 eyes had rings or arcs of increased FAF in the parafoveal area. For 12 eyes, visual sensitivity was preserved within areas of normal FAF; decreased across the areas of increased FAF; and markedly decreased or non-measurable outside the rings or arcs. The SD-OCT horizontal line scans through the central 10° showed disruption and/or loss of the inner-outer segments of the photoreceptors (IS-OS junction loss) and decreased ONL thickness that were associated with areas of decreased visual sensitivity and increased FAF. However for 3 eyes, IS-OS junction loss, decreased ONL thickness and decreased sensitivity occurred in areas that appeared to be normal on FAF.
Conclusions: :
In general, areas of increased FAF were associated with disruption of the IS-OS junction, decreased ONL thickness and decreased visual sensitivity. However 3 of 15 patients showed similar structural and functional changes in areas that appeared normal on FAF, stressing the importance of following disease progression with multimodal imaging (SD-OCT and FAF) and functional studies (perimetry).1. Hood, Lin, Lazow et al. IOVS 2008.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • perimetry