Mean Retinal Nerve Fiber Layer Research Articles

Rate of Initial Optic Nerve Head Capillary Density Loss and Risk of Visual Field Progression

Rapid initial optic nerve head capillary density loss may be used to assess the risk of glaucoma visual field progression. To investigate the association between the rate of initial optic nerve head capillary density loss from optical coherence tomography angiography (OCTA) and visual field progression. This was a retrospective study of a longitudinal cohort at a glaucoma referral center. A total of 167 eyes (96 with primary open-angle glaucoma and 71 with glaucoma suspect) of 109 patients were monitored for a mean (SD) of 5.7 (1.4) years from January 2015 to December 2022. Data analysis was undertaken in April 2023. The rates of initial capillary density and average retinal nerve fiber layer loss were calculated from the first 3 optic nerve head OCTA and OCT scans, respectively, during the initial follow-up (mean [SD], 2.0 [1.0] years). Based on the median rate, eyes were categorized into fast and slow progressor groups. The association between initial capillary density change or retinal nerve fiber layer thinning and visual field progression was evaluated using linear-mixed and time-varying Cox models. A total of 167 eyes of 109 patients (mean [SD] age, 69.0 [11.1] years; 56 [51.4%] female and 53 [48.6%] male) were assessed. Eighty-three eyes were slow OCTA progressors, while 84 eyes were fast with mean capillary density loss of -0.45% per year and -1.17% per year, respectively (mean difference, -0.72%/year; 95% CI,-0.84 to -0.60; P < .001). Similarly, 83 eyes were slow OCT progressors, while 84 eyes were fast with mean retinal nerve fiber layer thinning of -0.09 μm per year and -0.60 μm per year, respectively (mean difference, -0.51 μm/year; 95% CI,-0.59 to -0.43; P < .001). The fast OCTA and OCT progressors were associated with more rapid visual field loss (mean difference, -0.18 dB/year; 95% CI,-0.30 to -0.06; P = .004 and -0.17 dB/year; 95% CI,-0.29 to -0.06; P = .002, respectively). Fast OCTA progressing eyes were more likely to have visual field progression (hazard ratio, 1.96; 95% CI, 1.04-3.69; P = .04). Seventeen of 52 eyes (32.7%; 95% CI, 32.5-32.8) with fast OCTA and OCT progression developed subsequent visual field likely progression. Rapid initial optic nerve head capillary density loss from OCTA was associated with a faster rate of visual field progression and a doubling of the risk of developing event progression in this study. These findings may support clinical use of OCTA and OCT optic nerve head measurements for risk assessment of glaucoma progression.

Changes in retinal nerve fiber layer thickness may be the cause of post-COVID-19 headaches

ABSTRACT Objective The prevalence of post-COVID headaches is not low. The eye can be affected by this infection, but it is not clear yet what the relationship is between persistent headaches and the thickness of the retinal nerve fiber layer (RNFL) after COVID-19 infection this study aims to investigate the relationship between these subjects. Methods In this retrospective study, in patients who have had a persistent headache, SD-OCT analysis of RNFL was obtained, and RNLF thickness values before and after COVID-19 infection were analyzed. Results A total of 26 eyes from 13 patients (nine (69.2%) females, four (30.8%) males) with persistent headaches after COVID-19 infection were studied. The average age was 47,35 years for females and 63 years for males. The mean RNFL thickness of both eyes between before and after COVID-19 infection decreased, which was statistically significant. Conclusion In this study, a correlation between headache and changes in RNLF after COVID-19 infection was found. It may have wider ramifications to look into the COVID-19-associated headache phenotype of people with a history of migraines, contributing to a more comprehensive understanding of migraine pathogenesis. This relationship can provide further insight into this infection.

Longitudinal optical coherence tomography indices in idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) may result in optic nerve fiber loss and even atrophy. The timing of the optical coherence tomography (OCT) indices reaching the lowest point (nadir) and the factors that predict the patient's anatomical outcome are not known. We aimed to determine the timing and the factors that affect nadir retinal nerve fiber layer (RNFL) thickness. The medical records of 99 IIH patients who were treated from December 2009 to January 2020 were retrospectively reviewed. The mean RNFL thickness at presentation was 263.5 ± 106.4 µm. The mean time to nadir was 7.9 ± 6.3 months. The average RNFL and ganglion cell complex (GCC) thickness at the nadir were 92.6 ± 14.5 µm (47% showed thinning) and 77.9 ± 27.8 µm (70% showed thinning), respectively. The Frisén disc edema stage and average RNFL thickness at baseline correlated with a longer time to nadir, (r = 0.28 P = 0.003 and r = 0.24, P = 0.012, respectively). The nadir average RNFL thickness and the nadir average GCC thickness (r = 0.32, P = 0.001, r = 0.29, P = 0.002, respectively) correlated with the baseline visual field mean deviation. The final anatomical outcome of IIH episodes in this study resulted in RNFL and GCC thinning. The time to RNFL nadir and its values correlated with IIH severity at presentation.

The Impact of Social Vulnerability on Structural and Functional Glaucoma Severity, Worsening, and Variability

To determine the association between social vulnerability index (SVI) and baseline severity, worsening, and variability of glaucoma, as assessed by visual field (VF) and optical coherence tomography (OCT). Retrospective longitudinal cohort study. Adults with glaucoma or glaucoma suspect status in one or both eyes. VFs were derived from 7,897 eyes from 4,482 patients, while OCTs were derived from 6,271 eyes from 3,976 patients. All eyes had a minimum of 5 tests over follow-up using either the Humphrey Field Analyzer or the Cirrus HD-OCT. SVI, which measures neighborhood-level environmental factors, was linked to patient addresses at the census tract level. Rates of change in mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness were computed using linear regression. The slope of the regression line was used to assess worsening, while the standard deviation (SD) of residuals was used as a measure of variability. Multivariable linear mixed-effects models were used to investigate the impact of SVI on baseline, worsening, and variability in both MD and RNFL. We further explored the interaction effect of mean IOP and SVI on worsening in MD and RNFL. Glaucoma severity defined based on baseline MD and RNFL thickness. Worsening defined as MD and RNFL slope. Variability defined as the SD of the residuals obtained from MD and RNFL slopes. Increased (worse) SVI was significantly associated with worse baseline MD (β = -1.07 dB, 95% CI: [-1.54, -0.60]), thicker baseline RNFL (β = 2.46 μm, 95% CI: [0.75, 4.17]), greater rates of RNFL loss (β = -0.12 μm, 95% CI: [-0.23, -0.02]), and greater VF variability (β = 0.16 dB, 95% CI: [0.07, 0.24]). Having worse SVI was associated with worse RNFL loss with increases in IOP (βinteraction = -0.07, [95% CI: -0.12, -0.02]). Increased social vulnerability index score is associated with worse functional (VF) loss at baseline, higher rates of structural (OCT) worsening over time, higher VF variability, and a greater effect of IOP on RNFL loss. Further studies are needed to enhance our understanding of these relationships and establish their cause.

Evaluation of the relationship between FDG-PET hypometabolism and retinal layer thickness in patients with Alzheimer's disease.

We aimed to investigate the diagnostic value of Optical coherence tomography (OCT) in Alzheimer's disease (AD) and to assess the correlation between OCT and fluorodeoxyglucose (FDG)-positron emission tomography (PET) which shows high diagnostic agreement with findings from postmortem histopathology-the gold standard method. Patients who were diagnosed with AD-related dementia were selected for the study. Patients with a mini mental test (MMT) score between 18 and 23 were included in the study (n = 31). Volunteers with MMT ≥ 28 and no cognitive impairment were included in the study as the control group (n = 31). OCT imaging was performed in the patient and control groups after detailed ophthalmological examinations including visual acuity and intraocular pressure measurements. Brain glucose metabolism measurement was performed using 18 F-FDG PET/computed tomography. When adjusted for age and sex, mean retinal nerve fiber layer thickness (RNFL) thickness showed a significant difference between groups and the RNFL thickness in the superior temporal and superior nasal quadrants in AD-related mild dementia group showed a significant difference (p < 0.05). Furthermore, only the RNFL thickness in the inferior nasal quadrant of the right eye showed a significant difference between the groups (p = 0.016). It is thought that OCT is a promising imaging method in the elderly population due to its low-cost, non-invasive and easily applicability, and therefore, it may contribute in the future as a tool in the periodic follow-up of patients diagnosed with AD.

The effect of systemic sclerosis and its subtypes on ocular anterior and posterior segment parameters.

To evaluate anterior and posterior segment parameters in the eyes of patients with systemic sclerosis (SSc) and examine the effect of disease and disease subtypes on these parameters. This cross-sectional study included 54 eyes of 27 SSc patients and 54 eyes of 27 age- and sex-matched healthy controls. In addition to a complete ophthalmologic examination, all patients were examined using a Scheimpflug camera, specular microscopy, and spectral domain optical coherence tomography. The mean age of the patients was 52.5 ± 11.4years and 19 patients were female. Anterior chamber volume, central corneal thickness, and central macular thickness (CMT) were significantly lower in the eyes of SSc patients compared to healthy controls (p = 0.01, p = 0.03, and p = 0.006, respectively). When evaluated according to SSc subtype, CMT was lower in diffuse SSc patients (p = 0.001), while mean retinal nerve fiber layer (RNFL) and inferior quadrant RNFL values were lower in limited SSc (p = 0.003 and p = 0.005, respectively). In the eyes of patients with SSc, some ocular parameters may show decreases compared to healthy individuals, presumably secondary to disease-related vasculopathy and fibrosis. CMT and RNFL parameters may be affected differently according to disease subtype.

Relationship between Serum Homocysteine Levels and Manganese Superoxide Dismutase (MnSOD) on Retinal Nerve Fiber Layer (RNFL) Thickness in Diabetic Retinopathy and Non-Diabetic Retinopathy Patients

Introduction &amp; ObjectivesDiabetic retinopathy is a visual disorder caused by abnormalities in the retina, where there is aprogressive microangiopathy characterized by damage and blockage of fine blood vessels, resultingin impaired nutrition of the retina. This study is to find out the relationship between serumhomocysteine levels and MnSOD on retinal nerve fiber layer (RNFL) thickness in diabeticretinopathy and non-diabetic retinopathy patients.&#x0D; MethodsThis study is an analytic observational case-control study with a total of 31 subjects for each group.3cc of venous blood samples were taken to assess the serum levels of homocysteine and MnSOD andthen analyzed by ELISA method in the integrated laboratory of the USU Medical Faculty.&#x0D; ResultsThere was a significant difference in Avg RNFL and Nasal RNFL thickness between the two groups(p=0.015) with the mean Avg RNFL thickness being 100.94 (SD=17.04) and the mean RNFL nasalthickness being 90.16 (SD=33.68). The highest MnSOD levels were found in non-diabeticretinopathy subjects with a mean of 142.77 (SD=101.77). There was no significant relationshipbetween homocysteine and thickness of superior RNFL (p=0.346), inferior RNFL (p=0.292),temporal RNFL (p=0.109), nasal RNFL (p=0.190). However, a significant association was foundbetween homocysteine and Avg RNFL (p=0.007).&#x0D; ConclusionIn the group of cases of diabetic retinopathy, a significant relationship was found between Hcy andAvg RNFL (p=0.007). An increase in serum homocysteine levels will be followed by a decrease in thethickness of the Avg RNFL.

Changes in Neurodegeneration and Visual Prognosis in Branch Retinal Vein Occlusion after Resolution of Macular Edema

This study aimed to examine the thicknesses of the ganglion cell layer (GCL) and peripapillary retinal nerve fiber layer (RNFL) in eyes with resolved macular edema (ME) in branch retinal vein occlusion (BRVO) and determine their relationship with visual acuity (VA). This retrospective observational case–control study included 57 eyes of BRVO patients with resolved ME after treatment. The macular GCL thickness, peripapillary RNFL thickness, and central macular thickness (CMT) measured on swept-source optical coherence tomography scans with the contralateral eyes used as controls were evaluated. The mean CMT was 270.48 ± 32.7 μm; the mean RNFL thickness was 105.46 ± 25.94 μm in BRVO eyes. Although the average RNFL thickness was decreased in BRVO eyes compared to unaffected eyes, there was no significant difference between the groups. However, the temporal and nasal RNFL thicknesses were significantly different between the groups. The mean affected quadrant had a significantly thinner GCL compared to the corresponding opposite unaffected quadrant (p = 0.02). Final VA was significantly correlated with nasal and middle GCL thicknesses in the affected area (r = −0.512, p = 0.003 and r = −0.537, p = 0.001, respectively); no correlation was found between the average RNFL thickness and mean CMT. The peripapillary RNFL and GCL thicknesses of the affected area were reduced in BRVO eyes compared to unaffected eyes. VA significantly correlated with nasal and middle GCL thicknesses in the affected area. Inner retinal damage occurring in patients with ME secondary to BRVO may be related to the visual prognosis.

LIMBARE: An Advanced Linear Mixed-Effects Breakpoint Analysis With Robust Estimation Method With Applications to Longitudinal Ophthalmic Studies.

Broken stick analysis is a widely used approach for detecting unknown breakpoints where the association between measurements is nonlinear. We propose LIMBARE, an advanced linear mixed-effects breakpoint analysis with robust estimation, especially designed for longitudinal ophthalmic studies. LIMBARE accommodates repeated measurements from both eyes and over time, and it effectively addresses the presence of outliers. The model setup of LIMBARE and the computing algorithm for point and confidence interval estimates of the breakpoint were introduced. The performance of LIMBARE and other competing methods was assessed via comprehensive simulation studies and application to a longitudinal ophthalmic study with 216 eyes (145 subjects) followed for an average of 3.7 ± 1.3years to examine the longitudinal association between structural and functional measurements. In simulation studies, LIMBARE showed the smallest bias and mean squared error for estimating the breakpoint, with an empirical coverage probability of corresponding confidence interval estimates closest to the nominal level for scenarios with and without outlier data points. In the application to the longitudinal ophthalmic study, LIMBARE detected two breakpoints between visual field mean deviation (MD) and retinal nerve fiber layer thickness and one breakpoint between MD and cup-to-disc ratio, whereas the cross-sectional analysis approach detected only one and none, respectively. LIMBARE enhances breakpoint estimation accuracy in longitudinal ophthalmic studies, and the cross-sectional analysis approach is not recommended for future studies. Our proposed method and companion R package provide a valuable computational tool for advancing longitudinal ophthalmology research and exploring the association relationships among ophthalmic variables.

Retinal Nerve Fiber Layer Thickness (RNFLT) in Myopic &amp; Hypermetropic Eyes in a Subset of Pakistani Population

Objective: This study aimed to evaluate retinal nerve fiber layer (RNFL) thickness in healthy individuals with myopic and hypermetropic eyes, using optical coherence tomography (OCT).Study Design: A cross-sectional study. Place and Duration of Study: The study was carried out at the Department of Ophthalmology, Dr. Akil bin Abdul Qadir Institute of Ophthalmology, Karachi, Pakistan from January 2015 to June 2015.Methods: In this study, 300 eyes were included were examined using standard protocols by a single examiner. Subjects with a history of diabetic or hypertensive retinopathy, raised intraocular pressure (&gt; 21mmHg), and previous intraocular or laser surgery were excluded from the study. The mean retinal nerve fiber layer thickness was calculated in both myopic and hypermetropic eyes. Results: The mean global retinal nerve fiber layer thickness (RNFLT) in myopic eyes was found to be 93.98 ± 8.57 μm. In hypermetropic eyes, it was found to be 101.00 ± 6.58. This variation was found to be statistically significant with p-value of 0.001.Conclusion: We concluded that individuals with myopic eyes had significantly reduced retinal nerve fiber layer thickness whereas those with hypermetropic eyes showed an insignificant increase in RNFLT compared to emmetropic eyes.How to cite this: Mukhtar S, Hassan N, Lakhani M, Fatima U, Shaheen S, Raza I. Retinal Nerve Fiber Layer Thickness (RNFLT) in Myopic &amp; Hypermetropic Eyes in a Subset of Pakistani Population. Life and Science. 2024; 5(1): 54-60. doi: http://doi.org/10.37185/LnS.1.1.480

Which OCT Measure of the Optic Nerve Head Improves Fastest? Towards Optimizing Early Detection of Resolving Papilledema in Children.

Optical coherence tomography (OCT) has been used to monitor papilledema. This study aims to determine which OCT-derived measures of the optic nerve head (ONH) detect resolving papilledema in children faster than standard OCT measures. Children (≤18years of age) with papilledema who completed optic nerve SD-OCT pretreatment and had evidence of treatment response on one or more follow-up OCTs within 4months were included. Standard (mean circumpapillary retinal nerve fiber layer [cpRNFL] thickness), device-derived (per-quadrant cpRNFL) and custom (ONH height, maximum Bruch's membrane displacement [BMD], ONH volume [ONHV], and BMD volume) OCT measures were calculated. Per-eye generalized estimating equations (GEEs) modelled changes in device-derived and custom measures as a function of mean cpRNFL to identify those measures that resolved faster during early (0-2months) follow-up. Mean cpRNFL coefficients of greater than 1 indicated faster resolving papilledema. We included 52 eyes of 29 children (mean age, 12.8years; 72.4% female). In analysis of early follow-up visits (38 eyes from 22 children), nasal cpRNFL and maximum BMD in each quadrant resolved faster than mean cpRNFL (GEE coefficients range, 1.14-3.37). Inferior cpRNFL, superior, nasal, and inferior ONH heights and ONHV resolved slower than mean cpRNFL (GEE coefficients range, 0.67-0.87). Nasal cpRNFL is a promising device-derived OCT measure for the early detection of resolving papilledema in children compared with mean cpRNFL. Maximum BMD, a custom measure, also shows promise, but its calculation has not yet been incorporated into commercial OCT devices. This study guides the optimal use of OCT in capturing resolving papilledema in children.

Deep learning-based identification of eyes at risk for glaucoma surgery

To develop and evaluate the performance of a deep learning model (DLM) that predicts eyes at high risk of surgical intervention for uncontrolled glaucoma based on multimodal data from an initial ophthalmology visit. Longitudinal, observational, retrospective study. 4898 unique eyes from 4038 adult glaucoma or glaucoma-suspect patients who underwent surgery for uncontrolled glaucoma (trabeculectomy, tube shunt, xen, or diode surgery) between 2013 and 2021, or did not undergo glaucoma surgery but had 3 or more ophthalmology visits. We constructed a DLM to predict the occurrence of glaucoma surgery within various time horizons from a baseline visit. Model inputs included spatially oriented visual field (VF) and optical coherence tomography (OCT) data as well as clinical and demographic features. Separate DLMs with the same architecture were trained to predict the occurrence of surgery within 3 months, within 3–6 months, within 6 months–1 year, within 1–2 years, within 2–3 years, within 3–4 years, and within 4–5 years from the baseline visit. Included eyes were randomly split into 60%, 20%, and 20% for training, validation, and testing. DLM performance was measured using area under the receiver operating characteristic curve (AUC) and precision-recall curve (PRC). Shapley additive explanations (SHAP) were utilized to assess the importance of different features. Model prediction of surgery for uncontrolled glaucoma within 3 months had the best AUC of 0.92 (95% CI 0.88, 0.96). DLMs achieved clinically useful AUC values (> 0.8) for all models that predicted the occurrence of surgery within 3 years. According to SHAP analysis, all 7 models placed intraocular pressure (IOP) within the five most important features in predicting the occurrence of glaucoma surgery. Mean deviation (MD) and average retinal nerve fiber layer (RNFL) thickness were listed among the top 5 most important features by 6 of the 7 models. DLMs can successfully identify eyes requiring surgery for uncontrolled glaucoma within specific time horizons. Predictive performance decreases as the time horizon for forecasting surgery increases. Implementing prediction models in a clinical setting may help identify patients that should be referred to a glaucoma specialist for surgical evaluation.

Establishing Optic Nerve Diameter Threshold Sensitive and Specific for Optic Atrophy Diagnosis.

To determine apotential threshold optic nerve diameter (OND) that could reliably differentiate healthy nerves from those affected by optic atrophy (OA) and to determine correlations of OND in OA with retinal nerve fiber layer (RNFL) thickness, visual acuity (VA), and visual field mean deviation (VFMD). This was aretrospective case control study. Magnetic resonance (MR) images were reviewed from individuals with OA aged 18years or older with vision loss for more than 6months and an OA diagnosis established by aneuro-ophthalmologist. Individuals without OA who underwent MR imaging of the orbit for other purposes were also collected. OND was measured on coronal T2-weighted images in the midorbital section, 1cm posterior to the optic disc. Measurements of mean RNFL thickness, VA and VFMD were also collected. In this study 47 OA subjects (63% women, 78eyes) and 75 normal subjects (42.7% women, 127 eyes) were assessed. Healthy ONDs (mean 2.73 ± 0.24 mm) were significantly greater than OA nerve diameters (mean 1.94 ± 0.32 mm; P < 0.001). Athreshold OND of ≤2.3 mmhadasensitivity of 0.92 and aspecificity of 0.93 in predicting OA. Mean RNFL (r = 0.05, p = 0.68), VA (r = 0.17, p = 0.14), and VFMD (r = 0.18, p = 0.16) were not significantly associated with OND. ONDs are significantly reduced in patients with OA compared with healthy nerves. Athreshold OND of ≤2.3 mm is highly sensitive and specific for adiagnosis of OA. OND was not significantly correlated with RNFL thickness, VA, or VFMD.

Evaluation of Retinal Nerve Fibre Layer in Diabetic Patients as an Early Manifestation of Diabetic Retinopathy

Purpose: To evaluate retinal nerve fibre layer (RNFL) in diabetic patients as an early manifestation of diabetic retinopathy (DR). Method: This comparative study was conducted on 30 diabetic patients who were had no signs of DR, and in the control group comprising 30 healthy non-diabetic patients selected as sample size. Demographic data including their age, duration of diabetes, drugs used for treatment, hypertension and previous ocular surgery were noted. Complete ophthalmological examination was performed, including slit-lamp biomicroscopy, refraction, intraocular pressure measurement, dilated fundus examination, fundus fluorescein angiography for patients with non-proliferative DR and optical coherence tomography imaging using Heidelberg Spectralis. Results: The RNFL thicknesses in each of the quadrants were analysed and then a comparison was done in case and control groups. Also, RNFL thickness among all study participants with HbA1c levels was investigated. The mean RNFL thickness in the superior.inferior nasal and temporal quadrants were 119.2, 120.1, 80.6 and 63.2, respectively. The mean thickness was noted in each group in each of the quadrants and was found to be lesser than the control population of diabetics. Conclusion: The imaging of RNFL may be an important tool in assessing diabetes.related changes early and should be made part of diabetic screening.

Neuro-ophthalmic features of patients with spontaneous cerebrospinal fluid leaks.

Increased intracranial pressure is a potential cause of spontaneous cerebrospinal fluid (sCSF) leak. Associated neuro-ophthalmic features have not been well studied, particularly relationships with idiopathic intracranial hypertension (IIH). We hypothesized that neuro-ophthalmic features routinely used in evaluations for IIH can be useful in the investigation of a causal relationship between IIH and sCSF leak. We reviewed the neuro-ophthalmic examination and office-based ophthalmic imaging data of all consecutive patients with sCSF leaks and at least one repair to investigate the clinical and neuro-ophthalmic features of increased intracranial pressure. We conducted a retrospective longitudinal study at a single institution by querying the electronic medical record system for CSF leak Current Procedural Terminology (CPT) codes (G96.00 and G96.01) from June 1, 2019, to July 31, 2022. For patients with a confirmed diagnosis of sCSF leak, demographic information, eye examination results, and ophthalmic imaging details for both eyes were collected. A total of 189 patients with CSF leaks were identified through CPT coding; 159 had iatrogenic or traumatic CSF leaks, and 30 individuals (3 male, 27 female) had confirmed sCSF leaks. The mean age of patients with sCSF leaks was 46 years (range: 29 - 81), with a mean body mass index of 35.2 kg/m2 (range: 18.2 - 54.1). Only 11 of 30 underwent eye examinations (8 before surgical repair and 10 after). The mean pre-repair and post-repair best-corrected visual acuity were 20/30 (range: 20/20 - 20/55) and 20/25 (range: 20/20 - 20/40), respectively (P = 0.188). The mean retinal nerve fiber layer thickness was 99 µm (range: 96 - 104) pre-repair and 97 µm (range: 84 - 103) post-repair (P = 0.195). The mean ganglion cell complex thickness was 84 µm (range: 72 - 94) pre-repair and 82 µm (range: 71 - 94) post-repair (P = 0.500). Humphrey visual field average mean deviation was -5.1 (range: -12.4 - -1.8) pre-repair and -1.0 (range: -10.1 - 2.1) post-repair (P = 0.063). Serial neuro-ophthalmic examinations are recommended for patients with sCSF leaks to screen for signs of current or prior increased intracranial pressure. Larger studies are required to clarify the longitudinal changes in neuro-ophthalmic features, to investigate the incidence of IIH in cases of sCSF leak development or recurrence after surgical repair, and to explore potential causal relationships to guide post-repair management and prevent recurrent leaks. A multicenter consortium is also suggested to develop a standard clinical protocol for comprehensive management of sCSF leaks.

Assessment of Peripapillary Retinal Nerve Fiber Layer Optical Density Ratios in Healthy Eyes Using Optical Coherence Tomography with Different Analytical Radii

Purpose To explore the characteristics and determinants of peripapillary retinal nerve fiber layer (RNFL) optical density (OD) by optical coherence tomography (OCT) in healthy eyes with varied analytical radii. Methods Peripapillary OCT scans centered at the optic disc of 150 eyes from 150 healthy subjects (64 males and 86 females) were included. Under 5 analytical circles with different radii (1.45 mm, 1.7 mm, 1.95 mm, 2.2 mm and 2.45 mm), the circumpapillary circular cross-sectional images were exported for further analysis using Image J. Peripapillary RNFL and retinal pigment epithelium (RPE) OD in different quadrants and clock-hours were obtained. RNFL optical density ratio (ODR) was then calculated as RNFL OD divided by RPE OD. A linear mixed-effects model analysis was performed to assess the relationship between RNFL ODR and analytical radius, accounting for axial length, age, spherical equivalent, thickness and image score. Results The RNFL ODRs had a double-hump pattern with peaks in the superior and inferior quadrants and troughs in the temporal and nasal areas. In the linear mixed-effects model analysis, a trend of decreasing mean RNFL ODR with increasing analytical radius was found (0.9227 ± 0.0689, 0.9063 ± 0.0620, 0.8916 ± 0.0552, 0.8729 ± 0.0553 and 0.8575 ± 0.0564 respectively, p = 0.034). RNFL ODR values was negatively correlated with age (p < 0.001), positively correlated with corresponding RNFL thickness (p < 0.001). No significant correlation was found between RFNL ODR and image score, axial length and spherical equivalent. Conclusions RNFL ODR profile showed a comparable double-hump configuration with RNFL thickness. RNFL ODR values tended to decrease with larger analytical circles and older age, and increase with corresponding RNFL thickness. These factors should be considered when interpreting RNFL ODR in glaucoma assessment.

Structure-function relationship and diagnostic value of macular ganglion cell complex measurement using Fourier-domain OCT in glaucoma.

To evaluate the relationship between visual function and macular ganglion cell complex (GCC) thickness measured by Fourier-domain optical coherence tomography (OCT) and evaluate the diagnostic value of GCC measurement compared to retinal nerve fiber layer (RNFL) thickness and macular thickness in detecting early, moderate, and severe glaucomas. Subjects underwent standard automated perimetry (SAP), OCT imaging with optic nerve head mode and GCC mode. The relationship between OCT parameters (mean GCC thickness, mean RNFL thickness, and macular thickness) and perimetry global indices (mean deviation [MD] and pattern standard deviation [PSD]) was evaluated by regression analysis. Diagnostic values of mean RNFL thickness, GCC parameters, and macular thickness were compared with the area under the receiver operating characteristic curves (AUC). A total of 84 eyes, 42 of each normal and primary open-angle glaucoma patients were included in the study. Compared with linear models, second-order polynomial models better described relationships between GCC thickness and MD ( P < 0.001), and between GCC thickness and PSD ( P = 0.00). RNFL parameter, inferior RNFL thickness had the highest AUC for detecting early glaucoma. The AUC of mean GCC thickness for early glaucoma was higher than that of mean RNFL; however, the difference was not significant ( P = 0.09), which was higher than that of macular thickness. The relationship between visual field (VF) sensitivity and GCC thickness is best expressed by the curvilinear function. Macular GCC thickness and RNFL thickness showed similar diagnostic values but were better than macular thickness for detecting early glaucoma but inferior to macular thickness and RNFL thickness for detecting moderate glaucoma.

Short-term Detection of Fast Progressors in Glaucoma: The Fast Progression Assessment through Clustered Evaluation (Fast-PACE) Study

To evaluate the performance of an intensive, clustered testing approach in identifying eyes with rapid glaucoma progression over 6 months in the Fast-PACE (Progression Assessment through Clustered Evaluation) study. Prospective cohort study. 125 eyes from 65 primary open-angle glaucoma (POAG) subjects. Subjects underwent two sets of 5 weekly visits (clusters) separated by an average of 6 months, then were followed with single visits every 6 months for an overall mean follow-up of 25 months (mean of 17 tests). Each visit consisted of testing with standard automated perimetry (SAP) 24-2 and 10-2, and spectral-domain optical coherence tomography (SD OCT). Progression was assessed using trend analyses of SAP mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness. Generalized estimating equations were applied to adjust for correlations between eyes for confidence interval (CI) estimation and hypothesis testing. Diagnostic accuracy of the 6-month clustering period to identify progression detected during the overall follow-up. 19 of 125 eyes (15%, CI: 9%-24%) progressed based on SAP 24-2 MD over the 6-month clustering period. 14 eyes (11%, CI: 6%-20%) progressed on SAP 10-2 MD, and 16 (13%, CI:8%-21%) by RNFL thickness, with 30 of 125 eyes (24%, CI:16%-34%) progressing by function, structure, or both. Of the 35 eyes progressing during the overall follow-up, 25 had progressed during the 6-month clustering period, for a sensitivity of 71% (CI: 53%-85%). Of the 90 eyes that did not progress during the overall follow-up, 85 also did not progress during the 6-month period, for a specificity of 94% (CI: 88% - 98%). Of the 14 eyes considered fast progressors by SAP 24-2, 10-2 or SD OCT during the overall follow-up, 13 were identified as progressing during the 6-month cluster period, for a sensitivity of 93% (CI: 66% - 100%) for identifying fast progression with a specificity of 85% (CI: 77% - 90%). Clustered testing in the Fast-PACE study detected fast-progressing glaucoma eyes over six months. The methodology could be applied in clinical trials investigating interventions to slow glaucoma progression and may also be of value for short-term assessment of high-risk subjects.

The Impact of Achieving Target Intraocular Pressure on Glaucomatous Retinal Nerve Fiber Layer Thinning in a Treated Clinical Population

To estimate the effect of being below and above the clinician-set target intraocular pressure (IOP) on rates of glaucomatous retinal nerve fiber layer (RNFL) thinning in a treated real-world clinical population. Retrospective cohort study. A total of 3256 eyes (1923 patients) with ≥5 reliable optical coherence tomography scans and 1 baseline visual field test were included. Linear mixed-effects modeling estimated the effects of the primary independent variables (mean target difference [measured IOP - target IOP] and mean IOP, mm Hg) on the primary dependent variable (RNFL slope, µm/y) while accounting for additional confounding variables (age, biological sex, race, baseline RNFL, baseline pachymetry, and disease severity). A spline term accounted for differential effects when above (target difference >0 mm Hg) and below (target difference ≤0 mm Hg) target pressure. Eyes below and above target had significantly different mean RNFL slopes (-0.44 vs -0.71 µm/y, P < .001). Each 1 mm Hg increase above target had a 0.143 µm/y faster rate of RNFL thinning (P < .001). Separating by disease severity, suspect, mild, moderate, and advanced glaucoma had 0.135 (P = .002), 0.116 (P = .009), 0.203 (P = .02), and 0.65 (P = .22) µm/y faster rates of RNFL thinning per 1 mm Hg increase, respectively. Being above the clinician-set target pressure is associated with more rapid RNFL thinning in suspect, mild, and moderate glaucoma. Faster rates of thinning were also present in advanced glaucoma, but statistical significance was limited by the lower sample size of eyes above target and the optical coherence tomography floor effect.

Evaluation of the retina, choroid and optic disc vascular structures in individuals with a history of COVID-19

In this study, we aimed to detect changes in posterior segment structures and vascular density caused by COVID-19 using an optical coherence tomography angiography (OCTA) device. The study included 20 eyes of 20 patients no systemic or ocular disease who were followed at the Ophthalmology Clinic of Health Sciences University Antalya Training and Research Hospital. The OCTA images of these individuals taken prior to contracting COVID-19 and six months after recovery were examined. The mean choriocapillaris blood flow was 2.00±0.13mm2 before COVID-19 and 2.08±0.23mm2 after the disease, and the mean subfoveal choroidal thickness was 247.33±7.65μm before the disease and 273.08±4.92μm after the disease, indicating a statistically significant difference (P=0.003, P=0.001, respectively). The mean retinal nerve fiber layer thickness before and after COVID-19 were 119.33±3.88 and 117.50±3.92μm, respectively, representing a statistically significant decrease (P<0.001). This is the first study in the literature to evaluate the post-COVID-19 changes in the vascular structures of the eye compared to the pre-disease values. In this study, we found statistically significant changes in choriocapillaris blood flow, subfoveal chroidal thickness and retinal nerve fiber layer thickness after COVID-19 infection. Further research with a greater sample size is needed to explore the effect of COVID-19 on these parameters.