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An adaptive optics optical coherence tomography (AO-OCT) system is used to assess sixty healthy eyes of thirty subjects (age 22 to 75) to evaluate how the outer retinal layers, foveal eccentricity and age effect the mean cone density. The cone mosaics of different retinal planes (the cone inner segment outer segment junction (IS/OS), the cone outer segment combined with the IS/OS (ISOS+), the cone outer segment tips (COST), and the full en-face plane (FEF)) at four main meridians (superior, nasal, inferior, temporal) and para- and perifoveal eccentricities (ecc 2.5° and 6.5°) were analyzed quantitatively. The mean overall cone density was 19,892/mm2 at ecc 2.5° and 13,323/mm2 at ecc 6.5°. A significant impact on cone density was found for eccentricity (up to 6,700/mm2 between ecc 2.5° and 6.5°), meridian (up to 3,700/mm2 between nasal and superior meridian) and layer (up to 1,400/mm2 between FEF and IS/OS). Age showed only a weak negative effect. These factors as well as inter-individual variability have to be taken into account when comparing cone density measurements between healthy and pathologically changed eyes, as their combined effect on density can easily exceed several thousand cones per mm2 even in parafoveal regions.

Purpose The purpose of this study was to assess density and morphology of cone photoreceptors (PRs) and corresponding retinal sensitivity in ischemic compared to nonischemic retinal capillary areas of diabetic eyes using adaptive optics optical coherence tomography (AO-OCT) and microperimetry (MP). Methods In this cross-sectional, observational study five eyes of four patients (2 eyes with proliferative diabetic retinopathy (DR) and 3 eyes moderate nonproliferative DR) were included. PR morphology and density was manually assessed in AO-OCT en face images both at the axial position of the inner-segment outer segment (IS/OS) and cone outer segment tips (COSTs). Retinal sensitivity was determined by fundus-controlled microperimetry in corresponding areas (MP-3, Nidek). Results In AO-OCT, areas affected by capillary nonperfusion showed severe alterations of cone PR morphology at IS/OS and COST compared to areas with intact capillary perfusion (84% and 87% vs. 9% and 8% of area affected for IS/OS and COST, respectively). Mean reduction of PR signal density in affected areas compared to those with intact superficial capillary plexus (SCP) and deep capillary plexus (DCP) perfusion of similar eccentricity was –38% at the level of IS/OS ( P = 0.01) and –39% at the level of COST ( P = 0.01). Mean retinal sensitivity was 10.8 ± 5.4 in areas affected by DCP nonperfusion and 28.2 ± 1.5 outside these areas ( P < 0.001). Conclusions Cone PR morphology and signal density are severely altered in areas of capillary nonperfusion. These structural changes are accompanied by a severe reduction of retinal sensitivity, indicating the importance of preventing impaired capillary circulation in patients with DR.

Purpose The assessment of cup-disc ratio as a surrogate parameter for the neuroretinal rim width (NRW) of the optic nerve is well established, but prone to human error and imprecision. Objective assessment of the NRW is provided by spectral domain optical coherence tomography (SD-OCT). This study is the first to systematically compare NRW measurements acquired with the Carl Zeiss Meditech Cirrus HD-OCT 5000 and the Heidelberg Engineering Spectralis SD-OCT. Methods In this cross-sectional study, 20 eyes of each 20 glaucoma patients and 20 age-matched healthy controls underwent ophthalmic examination, SD-OCT imaging, and computer perimetry. Regression analyses were performed for the NRW comparability and the effect of the rotational alignment disconcordance (RAD), receiver-operating characteristics (ROC) for NRWbased healthy glaucoma discrimination capability, and Pearson's correlation for covariate association. Results Mean NRW differences were 8 ± 48 μm (p = 0.4528), 91 ± 80 μm (p < 0.01), and 49 ± 77 μm (p < 0.001) in the glaucoma, healthy, and whole group. On average, the Cirrus showed higher NRW values (+ 50 μm) than the Spectralis, this difference increased with values starting with 159 μm. Discrimination ROC were 1.0 (Spectralis) and 0.9675 (Cirrus). RAD showed very little effect on NRW (R 2 = 0.9661, p < 0.001). NRW-covariate correlation was highly significant (p < 0.001) with both devices for clinical cup/disc ratio, calculated rim width, visual field mean, and pattern deviations. Conclusions Our results suggest to only cautiously compare Spectralis and Cirrus NRW measurements only in patients with morphologically manifest glaucoma. For morphological progression analysis, we recommend the continuous usage of the same device.

Purpose: To evaluate neuroretinal integrity in different subtypes of optical coherence tomography (OCT)-graded partial-thickness macular holes. Methods: Fovea-centred SD-OCT images (Cirrus, Carl Zeiss Meditec AG; Spectralis, Heidelberg Engineering GmbH) and visual acuity (VA) acquired at every visit were analysed by two retina specialists retrospectively in 71 eyes of 65 patients. Partial-thickness macular holes were classified as lamellar macular hole (LMH), epiretinal membrane foveoschisis (ERMF) or macular pseudohole (MPH). Results: Lamellar macular hole, ERMF and MPH were diagnosed in 33 (47%), 31 (43%) and 7 (10%) eyes with a VA of 0.18 AE 0.25, 0.15 AE 0.2, and 0.06 AE 0.08 (p = 0.323), respectively. Median follow-up time was 11 (interquartile range 4-32.5), 10 (interquartile range 5-18) and 19 (interquartile range 8-24) months in LMH, ERMF and MPH. In all subgroups, VA remained stable during the follow-up (p = 0.652, p = 0.915 and p = 1.000). Epiretinal proliferations (EP) were present in 12 LMH and 3 ERMF. At baseline, eyes with EP had significantly worse VA (p < 0.001), wider foveal cavities (p = 0.007) and thinner foveal floors (p < 0.001) compared with eyes without EP. Twelve out of 15 eyes with EP showed exudative cystoid spaces. Among all 71 eyes, 51 remained morphologically and functionally stable during follow-up. Conclusion: In our study cohort, EP are associated with worse VA and advanced neuroretinal tissue loss presenting with wider foveal cavities and thinner foveal floors. During the follow-up period, VA remained stable in all entities of partialthickness macular holes.