Abstract
Purpose :
To present an objective approach to study the structure and function of the cones in inherited retinal dystrophies
Methods :
Six patients suffering from inherited retinal dystrophies were recruited in a prospective study for monitoring structure and function of the cones. High-resolution images of the cone mosaic were obtained with a flood-illumination adaptive optics (AO) retinal camera. Moreover, objective assessment of the eye included Best Corrected Visual acuity (BCVA), Contrast Sensitivity Function (CSF), microperimetry (MP1), Goldmann visual field, full-field and multifocal electroretinography (mfERG), combined scanning laser ophthalmoscope (SLO) and spectral domain-optical coherence tomography (SD-OCT) imaging
Results :
The six probands had a diagnosis, confirmed by genetic testing, of adult onset foveomacular vitelliform dystrophy (AOFVD), Best's macular dystrophy (BVMD), Retinitis Pigmentosa (RP), Stargardt's disease (STGD), Occult Macular Dystrophy (OMD) and Cone Dystrophy (CD). The combined analysis of the cone mosaic in AO images, the ellipsoid zone in SD-OCT images and the mfERG rings allowed to classify and monitor each inherited retinal dystrophy. AO image analysis demonstrated severe cone loss with respect to controls in eyes with asymmetric STGD disease presentation and in absence of visual complaints. AO was reliable to monitor the changes of the cone mosaic at a cellular level, whereas psychophysical tests were unable to detect changes in visual function in RP and BVMD. Analysis of both AO and SD-OCT images provided reliable biomarkers to unveil the abnormalities of the cones in a case of OMD. Analysis of SD-OCT images and mfERG recordings provided abnormal measures with respect to controls in patients affected by AOFVD, BVMD and CD
Conclusions :
The multimodal approach for investigating the structure and function of the cones allows to detect and track their pathological changes with high accuracy over time in patients affected by degenerative retinal diseases. The quantitative assessment of cone survival or loss, based on AO imaging, is valuable for monitoring disease progression at a cellular level and to provide evidence of slow or minor changes in degenerative processes, which show high variability of the functional parameters
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.