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Purpose: Retinitis pigmentosa (RP), the most common inherited retinal disease, is characterized by progressive photoreceptor degeneration. It remains unknown to what extent surviving photoreceptors transduce light and support vision in RP. To address this, we correlated structure and functional measures using adaptive optics scanning laser ophthalmoscopy (AOSLO), adaptive optics microperimetry, and adaptive optics optical coherence tomography (AO-OCT)-based optoretinograms (ORGs)., Methods: Four patients with RP were imaged with AOSLO across the visual field covering the transition zone (TZ) of normal to diseased retina. Cone density was estimated in discrete regions spanning the TZ. Visual sensitivity was assessed by measuring increment thresholds for a 3-arcmin stimulus targeted via active eye tracking in AOSLO. ORGs were measured at the same locations using AO-OCT to assess the cones' functional response to a 528 ± 20-nm stimulus. Individual cone outer segment (COS) lengths were measured from AO-OCT in each subject., Results: Cone density was significantly reduced in patients with RP. Density reduction correlated with TZ location in 3 patients with RP, while a fourth had patches of reduced density throughout the retina. ORG amplitude was reduced in regions of normal and reduced cone density in all patients with RP. ORG response and COS length were positively correlated in controls but not in patients with RP. Despite deficits in cone density and ORG, visual sensitivity remained comparable to controls in three of four patients with RP., Conclusions: ORG-based measures of retinal dysfunction may precede deficits in cone structure and visual sensitivity. ORG is a sensitive measure of RP disease status and has significant potential to provide insight into disease progression and treatment efficacy.

Purpose: To evaluate visual function and disease progression in the retinal structural abnormalities of three patients from two unrelated families with macular telangiectasia (MacTel) type 2., Methods: Adaptive optics scanning laser ophthalmoscopy (AOSLO) and AOSLO microperimetry (AOMP) were used to evaluate the structure and function of macular cones in three eyes with MacTel type 2. Cone spacing was estimated using histogram analysis of intercone distances, and registered spectral-domain optical coherence tomography (SD-OCT) scans were used to evaluate retinal anatomy. AOMP was used to assess visual sensitivity in and around areas of apparent cone loss., Results: Although overall lesion surface area increased, some initially affected regions subsequently showed clear, contiguous, and normally spaced cone mosaics with recovered photoreceptor inner/outer segment (IS/OS) reflectivity (two of two eyes). The AOMP test sites fell within three categories: normal-appearing cones (N), dimly reflecting cones (D), and RPE cell mosaics (R). At N sites, AOMP threshold values (arbitrary units [au]) increased with increasing eccentricity (slope = 0.054 au/degree, r(2) = 0.77). The N thresholds ranged from 0.04 to 0.27 au, D thresholds from 0.04 to 0.33 au, and R thresholds from 0.14 to 1.00 au. There was measurable visual sensitivity everywhere except areas without intact external limiting membrane (ELM) and with diffuse scattering in the IS/OS and posterior tips of the outer segments (PTOS) regions on OCT., Conclusions: Visual sensitivity and recovery of cone visibility in areas of apparent focal cone loss suggests that MacTel type 2 lesions with a preserved ELM may contain functioning cones with abnormal scattering and/or waveguiding characteristics. (ClinicalTrials.gov number, NCT00254605.)., (Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.)