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Background/aims To determine the association of age, presence of optic nerve head drusen (ONHD) and number of previous intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections with inner retinal layer thicknesses in patients with pseudoxanthoma elasticum (PXE). Methods In this retrospective case-control study, longitudinal spectral-domain optical coherence tomography imaging data from patients with PXE were compared with controls. A custom deep-learning-based segmentation algorithm was trained and validated to quantify the retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL). The association of age, number of anti-VEGF injections and ONHD with the RNFL and GCL thickness in the outer ETDRS subfields as dependent variables was investigated using mixed model regression. Results Fourty-eight eyes of 30 patients with PXE were compared with 100 healthy eyes. The mean age was 52.5±12.9 years (range 21.3-68.2) for patients and 54.2±18.7 years (range 18.0-84.5) for controls. In patients, ONHD were visible in 15 eyes from 13 patients and 31 eyes had received anti-VEGF injections. In the multivariable analysis, age (-0.10 μm/year, p<0.001), the diagnosis of PXE (-2.03 μm, p=0.005) and an interaction term between age and the presence of ONHD (-0.20 μm/year, p=0.001) were significantly associated with the GCL thickness. Including the number of intravitreal injections did not improve the model fit. The RNFL thickness was not significantly associated with any of these parameters. Conclusions This study demonstrates a significant association of ageing and ONHD with GCL thinning in patients with PXE, but not with the number of anti-VEGF injections. Given the severity of inner retinal degeneration in PXE, a clinical trial investigating neuroprotective therapy warrants consideration. [ABSTRACT FROM AUTHOR]

Aims To identify morphological characteristics preceding the development of exudative neovascularisation secondary to Macular Telangiectasia type 2 (MacTel) using multimodal retinal imaging. Methods In this retrospective study, eyes with a minimum observation period of 6 months prior to the de novo diagnosis of an exudative neovascularisation secondary to MacTel were analysed. Morphological changes preceding the formation of neovascularisation were evaluated using colour fundus photography, infrared imaging, fluorescein angiography, macular pigment measurement and optical coherence tomography (OCT). OCT-angiography (OCT-A) images were additionally available in a subset of patients. Results Twenty eyes from 20 patients were examined over a median period of 17 months (range: 6-100 months). Eyes were characterised by an accelerated progression of ellipsoid zone loss (median of 0.013 mm2/month), increased thickness of the temporal parafovea and hyper-reflective lesions on OCT. The latter underwent morphological changes preceding the development of exudative neovascularisation, including an increase in size and density, and expansion to outer retinal layers and the retinal pigment epithelium. All eyes showed a foveal depletion of macular pigment. On OCT-A, a focal increase in blood flow was observed at the level of the outer retina/choriocapillaris, and retinal-retinal and retinal-choroidal anastomoses preceded the formation of exudative neovascularisation. Conclusions Multimodal imaging allows the identification of prognostic morphological features preceding the formation of exudative neovascularisation in MacTel. Eyes exhibiting these characteristics should be monitored closely and patients should be alert for emergent symptoms in order to detect and treat neovascularisation early and, thereby, prevent irreversible visual loss. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the study was to quantify choriocapillaris (CC) flow alterations in early Sorsby fundus dystrophy (SFD) and to investigate the relationship of the CC flow deficits with the choroidal and outer retinal microstructure. Methods: In this prospective case-control study, 18 eyes of 11 patients with early SFD and 31 eyes of 31 controls without ocular pathology underwent multimodal imaging, including spectral-domain optical coherence tomography (OCT), followed by deep-learning-based layer segmentation. OCT angiography (OCTA) was performed to quantify CC flow signal deficits (FDs). Differences in CC FD density between SFD patients and controls were determined, and the relationships with choroidal thickness, retinal pigment epithelium-drusen complex (RPEDC) thickness and outer retinal layer thicknesses were analyzed using mixed-model analysis. Results: SFD patients exhibited a significantly greater CC FD density than controls (estimate [95% CI]: +20.0%FD [13.3; 26.7], p < 0.001 for SFD patients), even when adjusted for age. Square-root transformed choroidal thickness was a structural OCT surrogate of the CC FD density (−2.1%FD per √µm, p < 0.001), whereas RPEDC thickness was not informative regarding CC FD (p = 0.061). The CC FD density was associated with an altered microstructure of the overlying photoreceptors (outer segments, inner segments, and outer nuclear layer thinning of −0.19 μm, −0.08 μm and −0.30 μm per %FD, respectively, all p < 0.001). Conclusions: Patients with early SFD exhibit pronounced abnormalities of CC flow signal on OCTA, which are not limited to areas of sub-RPE deposits seen on OCT imaging. Thus, analysis of the CC flow may enable clinical trials at earlier disease stages in SFD. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the utility of optical coherence tomography-angiography (OCT-A) for monitoring activity, progression and response to therapy of neovascularisations (NVs) secondary to macular telangiectasia type 2 (MacTel). Methods In a retrospective analysis, eyes with NVs secondary to MacTel were reviewed over a period of =8 months. Examinations at monthly intervals included visual acuity testing, dilated funduscopy, spectral domain-OCT and OCT-A. Eyes were treated with intravitreal VEGF (vascular endothelial growth factor)-inhibitors following a pro-re-nata (PRN) regime, and treatment decisions were based on morphological signs of activity as determined by B-scan OCT and funduscopy. Signs of neovascular activity were defined as an increase in retinal thickness, presence/increase of intraretinal/subretinal fluid and haemorrhages. Results A total of 19 eyes from 17 patients were analysed. Patients were evaluated over a mean period of 13.4 months (range: 8.9 to 24.2). OCT-A permitted the monitoring of both treatment effects (regression) and progression (growth) of NVs, but not neovascular activity. The growth of neovascular vessels was detectable in OCT-A before signs of activity occurred on OCT. NVs showed a progressive growth over time despite PRN-treatment and preferentially grew and extended within areas characterised by a focal reduction of choriocapillaris perfusion. Conclusions The results indicate that OCT-A represents a useful imaging modality for monitoring NV-progression and treatment effects in MacTel. We demonstrate its advantages over conventional B-scan OCT imaging, including an earlier detection of NV-progression, and propose an adjustment of the current OCT-controlled PRN treatment regime in order to prevent NV-progression and subsequent functional loss in neovascular MacTel. [ABSTRACT FROM AUTHOR]

Purpose: Two‐colour computerised perimetry is a technique developed for assessing cone‐ and rod‐function at fixed background luminances in retinal disease. However, the state of adaptation during testing is unknown but crucial in the interpretation of results. We therefore aimed to determine the adaptational state of rod‐ and cone‐mechanisms in two‐colour perimetry. Methods: Sensitivity to 480 nm (blue) and 640 nm (red) Goldmann size V targets was determined for 10 normal subjects aged 16 to 46 years at 17 locations in the central 60 degrees of the visual field under scotopic conditions and then from −1.5 log cd m−2 to 2 log cd m−2 (white background) in 0.5 log unit steps. Data were fitted with threshold versus intensity (tvi) functions of the form logT = logT0 + log ((A + A0)/A0)n. Results: No clear rod‐cone break was observed for 640 nm stimuli. For 480 nm stimuli, transition from rod‐detection to cone‐detection occurred at mesopic illumination levels, where rod adaptation approached Weber behaviour. Cone detection mechanisms did not display Weber‐like adaptation until the background luminance approached 1 log cd.m−2. Diseases resulting in a "filter effect" ‐ including disorders of the photoreceptors ‐ are therefore predicted to affect sensitivity when rod function is probed with short‐wavelength targets under scotopic conditions, but less so under mesopic conditions. Filter effects are similarly anticipated to affect cone function measured using long‐wavelength targets under mesopic conditions (e.g., during microperimetry), but less so under photopic conditions. Conclusions: Asymmetries in adaptation in automated two‐colour perimetry are predicted to artefactually favour the detection of losses in rod sensitivity under scotopic conditions and cones under mesopic conditions. [ABSTRACT FROM AUTHOR]