Structural and Functional Correlations of Hyperautofluorescent Foveal Patch in Usher Syndrome Patients

Abstract

Purpose: : To describe retinal structure and function in Usher patients with hyperautofluorescent foveal patch on fundus autofluorescence (FAF) and compare results with hyperautofluorescent parafoveal ring [1].

Methods: : Patients with hyperautofluorescent patch (9) and ring (18) without cystoid macular edema were gathered from group of 42 patients. Age of night vision loss, visual acuity (VA) and color vision with Ishihara tables (ISH) was determined for representative eyes. Goldman perimetry (II/1-4) and microperimetry (MP1) was performed. Radius of ring or patch, IS/OS, ELM and ONL thickness was measured with Heidelberg Engineering Spectralis software. In a diagnosis objective and perspective of gene therapy, exon sequencing of Usher genes and modifier PDZD7 is in process. A new multiplex-PCR technique has been developed for this purpose [2].

Results: : Hyperautofluorescent foveal patch was seen in 21% of patients; it correlated with ONL thinning and nonexistent (5/9) or very short (radius <0.5 mm) IS/OS junction. ELM was seen in all eyes and its length was almost identical to that of patch or outer ring border. Patches were surrounded with decreased FAF that on OCT in some cases correlated with RPE atrophy and white specks in ONL. Increased FAF seemed to associate with increased RPE reflectance. There were significant differences in average disease duration (32 vs. 18 years), VA (0.3 vs. 0.8), ISH (2/15 vs. 10/15), maximum retinal sensitivity (6 vs. 16 dB), II/4 visual field (3 vs. 9°) and central ONL thickness (75 vs. 112 μm) in patch vs. ring (p<0.05). All patients with foveal patch had VA 0.6 or less and no one could detect Goldmann II/1.

Conclusions: : Hyperautofluorescent foveal patch was seen in 21% of Usher patients and was associated with significantly worse retinal structure and function to that found in patients with typical ring. Difference may be due to longer disease duration, however since there were also patients with patches and short duration (9 years), a distinct phenotype may be in place in these patients.1. Lenassi et al. Correlation between Macular Morphology and Sensitivity in Patients with Retinitis Pigmentosa and a Hyperautofluorescent Ring. Invest Ophthalmol Vis Sci. 2011 Nov 222. Bonnet et al. Complete exon sequencing of all known Usher syndrome genes greatly improves molecular diagnosis

Keywords: retinal degenerations: hereditary • imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)