Retinal damage extends beyond the border of the detached retina in fovea-on retinal detachment.

PURPOSE: The aim of this study was to investigate the preoperative and postoperative change in retinal sensitivity in relation to the distance to the retinal detachment (RD) in patients with fovea-on RD. METHODS: We prospectively evaluated 13 patients with fovea-on RD and a healthy control eye. Preoperatively, OCT scans of the RD border and the macula were obtained. The RD border was highlighted on the SLO image. Microperimetry was used to assess the retinal sensitivity at the macula, the RD border and the retina around the RD border. At 6 weeks, 3 and 6 months postoperatively, follow-up examinations of OCT and microperimetry were performed in the study eye. Microperimetry was performed once in control eyes. Microperimetry data were overlaid on the SLO image. The shortest distance to the RD border was calculated for each sensitivity measurement. The change in retinal sensitivity was calculated as control-study. The relation between the change in retinal sensitivity and the distance to the RD border was assessed using a locally weighted scatterplot smoothing curve. RESULTS: Preoperatively, the greatest loss in retinal sensitivity was 21 dB at 3° inside the RD which decreased linearly, through the RD border, and reached a plateau of 2 dB at 4°. For 6 weeks and 3 months postoperatively, the greatest retinal sensitivity loss remained at 3° inside the RD but was 4 dB and sensitivity loss decreased linearly to a plateau of 0 dB at 5° outside the RD. At 6 months postoperatively, the greatest sensitivity loss was 2 dB at 3° inside the RD, and decreased linearly to a plateau of 0 dB at 2° outside the RD. CONCLUSIONS: Retinal damage extends beyond the detached retina. Retinal sensitivity loss of the attached retina decreased drastically as the distance to the RD increased. Postoperative recovery occurred for both attached and detached retina.

AIROGS: Artificial Intelligence for Robust Glaucoma Screening Challenge.

The early detection of glaucoma is essential in preventing visual impairment. Artificial intelligence (AI) can be used to analyze color fundus photographs (CFPs) in a cost-effective manner, making glaucoma screening more accessible. While AI models for glaucoma screening from CFPs have shown promising results in laboratory settings, their performance decreases significantly in real-world scenarios due to the presence of out-of-distribution and low-quality images. To address this issue, we propose the Artificial Intelligence for Robust Glaucoma Screening (AIROGS) challenge. This challenge includes a large dataset of around 113,000 images from about 60,000 patients and 500 different screening centers, and encourages the development of algorithms that are robust to ungradable and unexpected input data. We evaluated solutions from 14 teams in this paper and found that the best teams performed similarly to a set of 20 expert ophthalmologists and optometrists. The highest-scoring team achieved an area under the receiver operating characteristic curve of 0.99 (95% CI: 0.98-0.99) for detecting ungradable images on-the-fly. Additionally, many of the algorithms showed robust performance when tested on three other publicly available datasets. These results demonstrate the feasibility of robust AI-enabled glaucoma screening.

Frequency of Visual Fields Needed to Detect Glaucoma Progression: A Computer Simulation Using Linear Mixed Effects Model.

PRCIS: Irregular visual field test frequency at relatively short intervals initially and longer intervals later on in the disease provided acceptable results in detecting glaucoma progression. PURPOSE: It is challenging to maintain a balance between the frequency of visual field testing and the long-term costs that may result from insufficient treatment of glaucoma patients. This study aims to simulate real-world circumstances of visual field data to determine the optimum follow-up scheme for the timely detection of glaucoma progression using a linear mixed effects model (LMM). MATERIALS AND METHODS: An LMM with random intercept and slope was used to simulate the series of mean deviation sensitivities over time. A cohort study including 277 glaucoma eyes that were followed for 9.0±1.2 years was used to derive residuals. Data were generated from patients with early-stage glaucoma having various regular and irregular follow-up scenarios and different rates of visual field loss. For each condition, 10,000 series of eyes were simulated, and one confirmatory test was conducted to identify progression. RESULTS: By doing one confirmatory test, the percentage of incorrect progression detection decreased considerably. The time to detect progression was shorter for eyes with an evenly spaced 4-monthly schedule, particularly in the first 2 years. From then onward, results from twice-a-year testing were similar to results from examinations scheduled 3 times per year. CONCLUSIONS: Irregular visual field test frequency at relatively short intervals initially and longer intervals later on in the disease provided acceptable results in detecting glaucoma progression. This approach could be considered for improving glaucoma monitoring. Moreover, simulating data using LMM may provide a better estimate of the disease progression time.

Magnetic resonance imaging reveals possible cause of diplopia after Baerveldt glaucoma implantation.

PURPOSE: To assess if ocular motility impairment, and the ensuing diplopia, after Baerveldt Glaucoma device (BGI) implantation, is related to the presence of a large fluid reservoir (bleb), using Magnetic Resonance Imaging (MRI). METHODS: In a masked observational study (CCMO-registry number: NL65633.058.18), the eyes of 30 glaucoma patients with (n = 12) or without diplopia (n = 18) who had previously undergone BGI implantation were scanned with a 7 Tesla MRI-scanner. The substructures of the BGI-complex, including both blebs and plate, were segmented in 3D. Primary outcomes were a comparison of volume and height of the BGI-complex between patients with and without diplopia. Comparisons were performed by using an unpaired t-test, Fisher's Exact or Mann-Whitney test. Correlations were determined by using Spearman correlation. RESULTS: The median volume and height of the BGI-complex was significantly higher in patients with compared to patients without diplopia (p = 0.007 and p = 0.025, respectively). Six patients had an excessively large total bleb volume (median of 1736.5mm3, interquartile range 1486.3-1933.9mm3), four of whom experienced diplopia (33% of the diplopia patients). Fibrotic strands through the BGI plate, intended to limit the height of the bleb, could be visualized but were not related to diplopia (75% versus 88%; p = 0.28). CONCLUSIONS: With MRI, we show that in a significant number of diplopia cases a large bleb is present in the orbit. Given the large volume of these blebs, they are a likely explanation of the development of diplopia in at least some of the patients with diplopia after BGI implantation. Additionally, the MR-images confirm the presence of fibrotic strands. As these strands are also visible in patients with a large bleb, they are apparently not sufficient to restrict the bleb height.

DenseUNets with feedback non-local attention for the segmentation of specular microscopy images of the corneal endothelium with guttae.

Corneal guttae, which are the abnormal growth of extracellular matrix in the corneal endothelium, are observed in specular images as black droplets that occlude the endothelial cells. To estimate the corneal parameters (endothelial cell density [ECD], coefficient of variation [CV], and hexagonality [HEX]), we propose a new deep learning method that includes a novel attention mechanism (named fNLA), which helps to infer the cell edges in the occluded areas. The approach first derives the cell edges, then infers the well-detected cells, and finally employs a postprocessing method to fix mistakes. This results in a binary segmentation from which the corneal parameters are estimated. We analyzed 1203 images (500 contained guttae) obtained with a Topcon SP-1P microscope. To generate the ground truth, we performed manual segmentation in all images. Several networks were evaluated (UNet, ResUNeXt, DenseUNets, UNet++, etc.) and we found that DenseUNets with fNLA provided the lowest error: a mean absolute error of 23.16 [cells/mm[Formula: see text]] in ECD, 1.28 [%] in CV, and 3.13 [%] in HEX. Compared with Topcon's built-in software, our error was 3-6 times smaller. Overall, our approach handled notably well the cells affected by guttae, detecting cell edges partially occluded by small guttae and discarding large areas covered by extensive guttae.

Pointwise and Region-Wise Course of Visual Field Loss in Patients With Glaucoma.

Purpose: Accurate assessment of visual field (VF) trend may help clinicians devise the optimum treatment regimen. This study was conducted to investigate the behavior of VF sequences using pointwise and region-wise linear, exponential, and sigmoid regression models. Materials and Methods: In a retrospective cohort study, 277 eyes of 139 patients with glaucoma who had been followed for at least 7 years were investigated. Linear, exponential, and sigmoid regression models were fitted for each VF test location and Glaucoma Hemifield Test (GHT) region to model the trend of VF loss. The model with the lowest root mean square error (RMSE) was selected as the best fit. Results: The mean age (standard deviation [SD]) of the patients was 59.9 years (9.8) with a mean follow-up time of 9.3 (0.7) years. The exponential regression had the best fit based on pointwise and region-wise approaches in 39.3% and 38.1% of eyes, respectively. The results showed a better performance based on sigmoid regression in patients with initial VF sensitivity threshold greater than 22 dB (71.6% in pointwise and 62.2% in region-wise approaches). The overall RMSE of the region-wise regression model was lower than the overall RMSE of the pointwise model. Conclusions: In the current study, nonlinear regression models showed a better fit compared to the linear regression models in tracking VF loss behavior. Moreover, findings suggest region-wise analysis may provide a more appropriate approach for assessing VF deterioration. Translational Relevance: Findings may confirm a nonlinear progression of VF deterioration in patients with glaucoma.

Contrast-to-Noise Ratios to Evaluate the Detection of Glaucomatous Progression in the Superior and Inferior Hemiretina.

Purpose: To determine the sensitivity of optical coherence tomography (OCT) and standard automated perimetry (SAP) for detecting glaucomatous progression in the superior and inferior hemiretina. Methods: We calculated contrast-to-noise ratios (CNRs) for OCT retinal nerve fiber layer (RNFL) thickness of hemiretinas and for SAP mean total deviation (MTD) of the corresponding hemifields from longitudinal data (205 eyes, 125 participants). The glaucoma stage for each hemiretina was based on the corresponding hemifield's MTD. Contrast was defined as the difference of the parameter between two consecutive glaucoma stages, whereas noise was the measurement variability of the parameter in those stages. The higher the CNR of a parameter, the more sensitive it is to detecting progression in the transition between successive stages. Results: There were no statistically significant differences for the RNFL CNR and MTD CNR between superior and inferior hemiretinas. As the glaucoma stage of the opposite hemiretina worsened, the MTD CNR in the transition from moderate to advanced glaucoma significantly increased. The RNFL CNR in the transition from mild to moderate glaucoma significantly decreased in case of advanced glaucoma in the opposite hemiretina. Conclusions: Similar to full retinas, detecting conversion to glaucoma in hemiretinas is more sensitive with OCT than SAP, whereas with more advanced disease, SAP is more sensitive for detecting progression. More importantly, the sensitivity for detecting progression in one hemiretina with either technique depends on the glaucoma severity in the opposite hemiretina. Translational Relevance: Monitoring glaucomatous progression with either OCT or SAP partly depends on the glaucoma severity in the opposite hemiretina.

The long-term postoperative effect of the Baerveldt glaucoma drainage device and of a trabeculectomy on the corneal endothelium.

PURPOSE: To determine whether the postoperative corneal endothelial cell density (ECD) differs between glaucoma patients who underwent Baerveldt implant (BGI) surgery and patients who underwent a trabeculectomy (TE) over 5 years ago. METHODS: Cross-sectional, observational study including 34 patients who underwent TE and 36 patients who underwent BGI surgery 5-11 years ago, as part of a randomized clinical trial. None of the patients had a history of intraocular surgery prior to their glaucoma surgery. Central and peripheral ECD was measured by using a non-contact specular microscope. RESULTS: Central and peripheral ECD in the TE group was 2285 ± 371 cells/mm2 (mean ± SD) and 2463 ± 476 cells/mm2 , respectively. Central and peripheral ECD in the BGI group was 1813 ± 745 cells/mm2 and 1876 ± 764 cells/mm2 , respectively. The central and peripheral ECD was statistically significantly higher in the TE group than in the BGI group (p = 0.001 for both). Additional intraocular surgical interventions were more prevalent in the BGI group (23) than in the TE group (5) (p < 0.001). In a subanalysis, without eyes that had undergone additional surgical interventions, only the peripheral ECD was statistically significantly higher in the TE group compared with the BGI group (p = 0.011). For the BGI group, a longer postoperative period resulted in a lower central ECD (r = -0.614, p = 0.004). CONCLUSION: Long-term ECD in eyes that underwent a BGI was considerably lower compared with eyes that underwent a TE, mainly in the peripheral cornea. This suggests that BGI causes a larger decrease of ECD than TE. Additionally, the decrease after BGI appears to continue for a longer period than after TE.

MYOPIC PRESENTATION OF CENTRAL SEROUS CHORIORETINOPATHY.

PURPOSE: To increase insight into the myopic presentation of central serous chorioretinopathy (CSC) by comparing a large group of myopic patients with CSC with reference groups with only one of the diagnoses. METHODS: Myopic patients with CSC (spherical equivalent ≤-3D, n = 46), emmetropic patients with CSC (spherical equivalent -0.5 to 0.5 D, n = 83), and myopic, non-CSC patients (n = 50) were included in this multicenter cross-sectional study. Disease characteristics and imaging parameters, such as subfoveal choroidal thickness and indocyanine green angiography patterns, were compared between cases and reference groups. RESULTS: In myopic patients with CSC, median subfoveal choroidal thickness (286 µm [IQR 226-372 µm]) was significantly thicker than subfoveal choroidal thickness in myopic, non-CSC patients (200 µm [IQR 152-228 µm], P < 0.001) but thinner than emmetropic patients with CSC (452 µm [IQR 342-538 µm], P < 0.001). They also had pachyvessels in 70% of the eyes comparable with emmetropic CSC (76%, P = 0.70). Choroidal hyperpermeability was frequently present on indocyanine green angiography in both myopic and emmetropic CSC eyes. Need for treatment, treatment success, and recurrence rate were not significantly different between CSC groups. CONCLUSION: Myopic CSC presents with similar imaging and clinical characteristics as emmetropic CSC, apart from their thinner choroids. Keeping in mind the structural changes of myopia, other imaging characteristics could aid the diagnostic process.

Slowed Saccadic Reaction Times in Seemingly Normal Parts of Glaucomatous Visual Fields.

Purpose: In eye movement perimetry, peripheral stimuli are confirmed by goal-directed eye movements toward the stimulus. The saccadic reaction time (SRT) is regarded as an index of visual field responsiveness, whereas in standard automated perimetry (SAP), the visual field sensitivity is tested. We investigated the relation between visual field sensitivity and responsiveness in corresponding locations of the visual field in healthy controls and in patients with mild, moderate and advanced glaucoma. Materials and Methods: Thirty-four healthy control subjects and 42 glaucoma patients underwent a 54-point protocol in eye movement perimetry (EMP) and a 24-2 SITA standard protocol in a Humphrey Field Analyzer. The visual field points were stratified by total deviation sensitivity loss in SAP into 6 strata. A generalized linear mixed model was applied to determine the influence of the various factors. Results: The generalized linear mixed model showed that the mean SRT increased with increasing glaucoma severity, from 479 ms in the control eyes to 678 ms in the eyes of patients with advanced glaucoma (p < 0.001). Mean SRTs significantly increased with increasing SAP sensitivity loss. Even at the locations where no sensitivity loss was detected by SAP (total deviation values greater or equal than 0 dB), we found lengthened SRTs in mild, moderate and advanced glaucoma compared to healthy controls (p < 0.05) and in moderate and advanced glaucoma compared to mild glaucoma (p < 0.05). At locations with total deviation values between 0 and -3 dB, -3 and -6 dB and -6 and -12 dB, we found similar differences. Conclusions: The lengthened SRT in areas with normal retinal sensitivities in glaucomatous eyes, i.e., planning and execution of saccades to specific locations, precede altered sensory perception as assessed with SAP. Better understanding of altered sensory processing in glaucoma might allow earlier diagnosis of emerging glaucoma.

Attenuation coefficient estimation in Fourier-domain OCT of multi-layered phantoms.

Optical properties, such as the attenuation coefficients of multi-layer tissue samples, could be used as a biomarker for diagnosis and disease progression in clinical practice. In this paper, we present a method to estimate the attenuation coefficients in a multi-layer sample by fitting a single scattering model for the OCT signal to the recorded OCT signal. In addition, we employ numerical simulations to obtain the theoretically achievable precision and accuracy of the estimated parameters under various experimental conditions. Finally, the method is applied to two sets of measurements obtained from a multi-layer phantom by two experimental OCT systems: one with a large and one with a small Rayleigh length. Numerical and experimental results show an accurate estimation of the attenuation coefficients when using multiple B-scans.

Parafoveal Microvascular Alterations in Ocular and Non-Ocular BehÒ«et's Disease Evaluated With Optical Coherence Tomography Angiography.

Purpose: To compare quantitative optical coherence tomography angiography (OCT-A) measurements of the parafoveal microvasculature in retinal capillary plexuses among BehÒ«et uveitis (BU) patients, non-ocular BehÒ«et's disease (NOBD) patients, and healthy volunteers (HVs). Methods: Sixty-eight subjects were enrolled in this prospective observational cross-sectional study. OCT-A imaging was performed using the Heidelberg Engineering Spectralis OCT. A custom algorithm was developed to calculate the vessel density (VD) in three retinal vascular layers: deep capillary plexus, intermediate capillary plexus, and superficial vascular plexus. The foveal avascular zone (FAZ) and acircularity index were calculated for the whole retinal vascular complex. Results: We analyzed one eye from 21 BU patients (age, 51 ± 10 years), 23 NOBD patients (age, 48 ± 14 years), and 22 HVs (age, 44 ± 13 years). One-way multivariate analysis of covariance showed a statistically significant difference in VD among the three groups when combining the layers after controlling for scan quality (P < 0.001). The VD was lowest in the BU group and highest in the HV group in all layers. The FAZ area was also statistically significant different among the groups (P < 0.005), with the largest FAZ areas in BU patients and smallest FAZ areas in the HV group. However, no statistically significant difference was found for the acircularity index. Conclusions: The parafoveal microvasculature is affected not only in BU patients but also in NOBD patients. Most deviations in the retinal microcirculation in BehÒ«et patients were found in the deeper layers of the retina by using the quantitative VD measurement.

Intra- and Intergrader Agreement for Detection of OCT Angiographic Characteristics Associated With Type 3 Neovascularization.

Purpose: To examine the intra- and intergrader agreement on morphologic characteristics of type 3 neovascularization on optical coherence tomography angiography (OCT-A). Methods: OCT-A images of 22 eyes from 21 patients with a new-onset, treatment-naive type 3 neovascularization were included in this cross-sectional retrospective agreement study. Each image was graded three times by two independent medical retina specialists to assess intra- and intergrader agreement. The graders scored the presence or absence of the following vascular and structural features: intraretinal neovascularization (IRN), subretinal neovascularization, sub-retinal pigment epithelium (RPE) neovascularization (SRPEN), retinal choroidal anastomosis (RCA), intraretinal cysts, subretinal fluid, and pigment epithelial detachment. Agreement was analyzed for each feature using Gwet's AC1, к statistics, and percentage of agreement. Results: The best agreement (AC1) was found for intraretinal neovascularization (withingrader1: 0.94; withingrader2: 0.93 and between: 1.00) and intraretinal cysts (withingrader1, 1.00; withingrader2, 0.97 and between, 1.00). The poorest intragrader agreements were observed for SRPEN (withingrader1, 0.54 and withingrader2, 0.36) and RCA (withingrader1, 0.45 and withingrader2, 0.52), and the poorest intergrader agreement was found for SRPEN, RCA, and pigment epithelial detachment (0.18, 0.37, and 0.15, respectively). Conclusions: Although the agreement values were high for intraretinal features, considerable grader variability was found for the vascular and structural features in the deeper retina or under the RPE. Clinicians should be careful to base therapeutic decisions on qualitative OCT-A assessment, because even well-trained specialists show a considerable grader variation in their subjective evaluation. Translational Relevance: The clinical value of OCT-A imaging largely depends on the agreement of subjective evaluations by ophthalmologists.

ANATOMICAL CHANGES ON SEQUENTIAL MULTIMODAL IMAGING IN PERIFOVEAL EXUDATIVE VASCULAR ANOMALOUS COMPLEX.

PURPOSE: To report a series of 21 patients with perifoveal exudative vascular anomalous complex (PEVAC) and to investigate the anatomical changes over time. METHODS: We conducted a retrospective study. Clinical data of consecutive patients, presenting at the Rotterdam Eye Hospital between 2014 and 2019, were analyzed. The data collected included best-corrected visual acuity, fundus photography, optical coherence tomography (OCT), OCT-angiography, fluorescence angiography, and indocyanine green angiography. RESULTS: We included 21 patients with a PEVAC lesion with a mean follow-up of 24.3 ± 13.8 months (range, 9-46 months). Patients with PEVAC were on average 75.3 ± 11.1 years (range, 53-90 years). The large perifoveal vascular aneurysmal abnormality was associated with small retinal hemorrhages in six patients and hard exudates in three patients. The PEVAC lesion was associated with intraretinal cystic spaces on OCT in 15 patients. Twelve of 21 patients showed no changes in cystic spaces on OCT during follow-up: 9 patients had stable cystic spaces and 3 patients had no cystic spaces. In contrast, in 9 of 21 patients, we observed changes in cystic spaces on OCT during follow-up. In two patients, cystic spaces appeared during follow-up, and in seven patients, there was a spontaneous resolution of cystic spaces. In three of these seven patients, the PEVAC lesion completely disappeared. Two patients, with stable intraretinal cystic spaces on OCT, were treated with intravitreal injections of anti-vascular endothelial growth factor without improvement. CONCLUSION: Perifoveal exudative vascular anomalous complex is an idiopathic perifoveal retinal vascular abnormality that is associated with intraretinal cystic spaces. These intraretinal cystic spaces associated with a PEVAC lesion, and even the PEVAC lesion itself, can have a spontaneous resolution over time.

Multimodal imaging comparison of perifoveal exudative vascular anomalous complex and resembling lesions.

PURPOSE: Perifoveal exudative vascular anomalous complex (PEVAC) was initially described as an isolated aneurysmal lesion in healthy eyes. Similar aneurysmal abnormalities may occur in association with retinal vascular diseases such as diabetic retinopathy or retinal vein occlusions (PEVAC-resembling). The aim of this study was to compare several imaging characteristics of PEVAC and PEVAC-resembling lesions. METHODS: Ten eyes with a PEVAC and 27 eyes with a PEVAC-resembling lesion were included in this cross-sectional study. They were all imaged with optical coherence tomography (OCT), OCT angiography (OCT-A) and colour fundus photography (CFP). Several clinical, morphological and vascular characteristics were assessed and compared between both PEVAC types. RESULTS: All PEVAC lesions were unilateral, while PEVAC-resembling lesions appeared bilateral in 23% of patients (p > 0.05). Unilateral multifocal PEVAC-resembling lesions were more frequently observed (56%) than unilateral multifocal PEVAC lesions (10%, p < 0.01). Furthermore, 90% of the PEVAC lesions were located within 500 µm from the centre of the fovea, while this was only true for 56% of the PEVAC-resembling lesions (p > 0.05). No notable differences were observed in other studied characteristics. CONCLUSIONS: The clinical, morphological and vascular features of PEVAC and PEVAC-resembling lesions are similar based on multimodal imaging. Given the bilaterality and multifocality seen in PEVAC-resembling lesions, an underlying retinal vascular disease may stimulate the quantity of aneurysmal abnormalities. Due to the similarities with PEVAC-resembling lesions, PEVAC may also be considered a microangiopathy but with an unknown origin.

Detailed optical coherence tomography angiographic short-term response of type 3 neovascularization to combined treatment with photodynamic therapy and intravitreal bevacizumab.

PURPOSE: To explore the short-term vascular and structural changes of type 3 neovascularization using optical coherence tomography angiography (OCT-A) when treated with a combination of photodynamic therapy (PDT) and intravitreal bevacizumab (IVB), and to evaluate the course of different sequences of the combined therapies. METHODS: Thirty eyes of 29 treatment-naïve patients with a type 3 neovascularization were included in this prospective observational cohort study. They were all treated with PDT and IVB 2 weeks apart, starting either with PDT (PDT-first group) or IVB (IVB-first group). Optical coherence tomography angiography (OCT-A) imaging was performed at week 0, 2, 4 and 18, and best corrected visual acuity (BCVA) at week 0 and 18. Vascular, structural and functional features were graded and analysed over time. RESULTS: In all patients, at all follow-up visits, vascular and structural features were significantly more often decreased or resolved than unchanged or increased. Best corrected visual acuity (BCVA) significantly improved at 18 weeks. Vascular, structural and functional outcomes were all slightly better in the PDT-first group compared to the IVB-first group, although not statistically significant. CONCLUSION: Combined treatment of PDT and IVB is effective in short-term for type 3 neovascularization based on vascular and structural features. Initial treatment with PDT tended to be more effective than with IVB.

Analysis of attenuation coefficient estimation in Fourier-domain OCT of semi-infinite media.

The attenuation coefficient (AC) is an optical property of tissue that can be estimated from optical coherence tomography (OCT) data. In this paper, we aim to estimate the AC accurately by compensating for the shape of the focused beam. For this, we propose a method to estimate the axial PSF model parameters and AC by fitting a model for an OCT signal in a homogenous sample to the recorded OCT signal. In addition, we employ numerical analysis to obtain the theoretical optimal precision of the estimated parameters for different experimental setups. Finally, the method is applied to OCT B-scans obtained from homogeneous samples. The numerical and experimental results show accurate estimations of the AC and the focus location when the focus is located inside the sample.

Smaller Foveal Avascular Zone in Deep Capillary Plexus Is Associated with Better Visual Acuity in Patients after Macula-off Retinal Detachment Surgery.

Purpose: To associate the change in the foveal avascular zone (FAZ) and vessel density (VD) with final best corrected visual acuity (BCVA) in eyes after macula-off rhegmatogenous retinal detachment surgery, and to investigate the evolution of FAZ and VD during 12 months of follow-up. Methods: We prospectively evaluated 47 patients with macula-off rhegmatogenous retinal detachment and healthy fellow eyes. At 1.5, 3.0, 6.0, and 12.0 months postoperatively, optical coherence tomography angiography scans were obtained from both eyes on a 3.0 × 3.0 mm macula-centered grid. En face images of the superficial vascular plexus, intermediate capillary plexus and deep capillary plexus were used to quantify FAZ and VD. BCVA was assessed with ETDRS-charts (logarithm of the minimal angle of resolution).At 12 months postoperatively, the association between the change in optical coherence tomography angiography parameters and visual function in study eyes was evaluated using the Spearman correlation coefficient. We calculated the BCVA difference and the percentage difference of FAZ and VD between the study and control eye. The evolution of FAZ and VD was investigated with linear mixed-effects models with nested random effects (eyes nested within patients). Results: At 12 months postoperatively, FAZ difference of the deep capillary plexus and BCVA difference were correlated (P = 0.0004, rs = 0.5). Furthermore, there was no evidence that FAZ and VD changed during follow-up. Conclusions: Although FAZ and VD remained stable during 12 months after surgery for macula-off rhegmatogenous retinal detachment, a smaller FAZ in the deep capillary plexus is associated with better BCVA. Translational relevance: Reduction in FAZ area may be caused by angiogenesis to counteract ischemia, therefore therapeutic stimulation of angiogenesis could be beneficial to visual recovery.