Peripapillary Retinal Thickness Research Articles

Linkage of Diabetic Retinopathy with Blood Antioxidants and Gut Microbiota in Type Two Diabetes Mellitus Saudi Patients

Background: The retina is a light-sensitive nerve layer located at the back of the eye that creates images of objects. These cells kept alive by getting oxygen and nutrients from tiny blood vessels in the eye. Retinopathy is a disease of the retina that is more prevalent in type 2 diabetes mellitus patients. Diabetic retinopathy is a leading cause of blindness because hyperglycemia weakens retinal capillaries, resulting in leakage of blood into the surrounding space. This bleeding can result in formation of scar tissue, which can cause traction retinal detachment and maculopathy. The development of a panel of blood biomarkers to monitor diabetic retinopathies is essential for both diagnosis and prognosis. Proteomics as a powerful tool for the analysis of complex mixtures of proteins and the identification of biomarkers can be of great importance. Purpose: To detect early nerve fiber layer changes around macula and optic disc in diabetic patients and to correlate diabetic retinopathy with blood antioxidants and gut microbiota in T2DM in Saudi patients. Materials and Methods: In this cross-sectional case-control study, a total of 77 eyes of 39 subjects aged 40-60 years who did not have any history of eye injuries or eye diseases affecting fundus viewing, were recruited from King Saud University Campus and the department of ophthalmology in King Abdul Aziz university hospital in Riyadh. All subjects underwent full ophthalmic examination including Peripapillary retinal nerve fiber layer thickness and macular profile, Proteomic approach of collected overnight fasting plasma and Microbial stool examination. Results: The nerve fiber layer thickness around the optic disc was measured for all groups and there was no statistically significant difference in all quadrants between groups. The total retinal thickness at the macular area was different among all groups and tends to increase in group 3 due to diabetic retinopathy. The macular thickness in the 4 quadrants revealed no statistical difference except in the inferior quadrant. Glutathione S transferase and lipid peroxides showed no significant difference between the three studied groups; vitamin C and Glutathione were surprisingly higher in controlled diabetic patients relative to controls. Moreover, over growth of bacteroids participated to the evolution of retinopathy in diabetic patients. Conclusion: As hyperglycemia and oxidative stress are implicated in the pathogenesis of diabetic retinopathy, the present study certified that the progressive damage can be delayed in controlled type 2 diabetic patients using different treatment modalities that subside oxidative stress.

Associations of Peripapillary Retinal Nerve Fiber Layer and Macular Retinal Layer Thickness with Serum Homocysteine Concentration

Associations of Peripapillary Retinal Nerve Fiber Layer and Macular Retinal Layer Thickness with Serum Homocysteine Concentration

OPTICAL COHERENCE TOMOGRAPHY ANALYSIS OF RETINAL THICKNESS IN COVID-19 PATIENTS

OBJECTIVE: The aim of this study was to perform Optical Coherence Tomography analysis of retinal changes in patients with COVID-19 infection and compare them with healthy controls. MATERIAL AND METHODS: For this purpose, 42 COVID-19 positive patients (group 1) and 44 healthy adults (group 2), aged between 18 and 68 years, who were admitted to our clinic between October 1, 2020 and May 1, 2021, were included in the study. Central foveal thickness, choroidal thickness (subfoveal) and peripapillary retinal nerve fiber thickness were measured. Measurements were performed at the central fovea and at 1500 μm nasal and 1500 μm temporal points from the central fovea. RESULTS: Age and gender distribution were similar in the groups (p=0.610 and p=0.992, respectively). However, central foveal thickness (p<0.001), subfoveal choroidal thickness (p=0.001) and peripapillary retinal nerve fiber layer thickness (p<0.001) were significantly different between the two groups. CONCLUSIONS: In conclusion, central fovea, subfoveal choroidal and peripapillary retinal nerve fiber layer thickness were higher in polymerase chain reaction positive COVID-19 patients compared to healthy controls. To understand the pathogenesis of systemic and local changes caused by COVID-19, multicenter and long-term studies with a large number of patient subgroups are necessary.

Myopia and Rate of Peripapillary Retinal Nerve Fiber Layer Thickness in Diabetic Patients Without Retinopathy: A 2-Year Longitudinal Study

Purpose The aim of this study was to investigate the association between myopia and longitudinal changes in peripapillary retinal nerve fiber layer (pRNFL) thickness in type 2 diabetic patients without diabetic retinopathy (DR). Methods A total of 1069 participants with a median follow-up time of 1.9 years were included in this study. The participants were categorized into four groups based on the presence of myopia (≤ –0.5 diopter [D]) and diabetes without DR, including a control group (n = 412), diabetes group (n = 416), myopia group (n = 115), and diabetes + myopia group (n = 126). Peripapillary average and sectoral RNFL measurements were obtained using 6 × 6 mm swept-source optical coherence tomography (SS-OCT) scans centered at the optic disc. The change rate of pRNFL, adjusted for age and sex, was calculated and compared among the four groups to investigate the impact of myopia and diabetes. Results The baseline estimated pRNFL thickness after adjustment for covariates was 113.7 μm, 116.2 μm, 108.0 μm, and 105.6 μm in the control, diabetes, myopia, and diabetes + myopia group, respectively (diabetes > control > myopia = diabetes + myopia, p < 0.001). The respective average pRNFL loss in the four groups was –0.48 μm/year, –1.11 μm/year, –1.23 μm/year, and -2.62 μm/year (all p < 0.01). The diabetes + myopia group exhibited a greater rate of average pRNFL reduction compared to the other groups (all p < 0.001). Multivariate analysis using a linear mixed-effects model showed that age, diabetes, axial length (AL), and baseline pRNFL thickness were significantly associated with the rate of average pRNFL reduction. Conclusions The diabetes group showed a faster rate of average pRNFL thickness reduction compared to healthy controls, regardless of the presence of myopia. The average pRNFL thickness decreased more rapidly when diabetes and myopia were present simultaneously than in the individual diabetes or myopia group. Both diabetes and myopia were associated with accelerated pRNFL loss.

Peripapillary Retinal Nerve Fiber Layer Thickness as a Predictor of Visual Outcomes in Patients with Acute Nonarteritic Anterior Ischemic Optic Neuropathy.

To evaluate the utility of peripapillary retinal nerve fiber layer thickness (pRNFLT) for the prediction of visual outcomes, including visual acuity (VA) and visual field (VF), in subjects with acute nonarteritic anterior ischemic optic neuropathy (NAION). We performed a retrospective study of data relating to 60 eyes of 60 subjects with acute NAION. Of these, reliable VF values were obtained at both the initial and at 6-month follow-up visits for 30 eyes, which were included in the VF analysis. The pRNFLT was measured globally and separately in all four quadrants (superior, inferior, nasal, and temporal) using optical coherence tomography at the initial visit. Multivariate analysis and the area under the curve (AUC) were used to evaluate the utility of pRNFLT for the prediction of visual outcomes, including favorable VA (VA better than or equal to 20/25) and favorable VF (visual field index (VFI) ≥90%), at the 6-month follow-up visit. The median VA and mean VFI at the initial visit were 0.40 (interquartile range (IQR): 0.40, 0.54; logarithm of the minimum angle of resolution (logMAR)) and 73.07% ± 6.73%, respectively. The median VA and mean VFI at the 6-month follow-up visit were 0.30 (IQR: 0.00, 0.70) logMAR and 69.27% ± 28.94%, respectively. Thinner temporal-quadrant pRNFLT was associated with favorable VA (odds ratio 0.98; p = 0.042) with a cut-off value of 128 µm (AUC 0.839, 95% CI: 0.732-0.947, sensitivity 77.27%, specificity 84.21%). Thinner nasal-quadrant pRNFLT was associated with favorable VF (odds ratio 0.97; p = 0.047) with a cut-off value of 105 µm (AUC 0.780, 95% CI: 0.612-0.948, sensitivity 90.00%, specificity 70.00%). The pRNFLT is clinically useful for the prediction of visual outcomes in patients with acute NAION. A temporal-quadrant pRNFLT ≤128 µm and a nasal-quadrant pRNFLT ≤105 µm predict favorable VA and VF at the 6-month follow-up visit, respectively.

Linkage of diabetic retinopathy with blood antioxidants and gut microbiota in type two diabetes mellitus Saudi patients

Background: The retina is a light-sensitive nerve layer located at the back of the eye that creates images of objects. These cells kept alive by getting oxygen and nutrients from tiny blood vessels in the eye. Retinopathy is a disease of the retina that is more prevalent in type 2 diabetes mellitus patients. Diabetic retinopathy is a leading cause of blindness because hyperglycemia weakens retinal capillaries, resulting in leakage of blood into the surrounding space. This bleeding can result in formation of scar tissue, which can cause traction retinal detachment and maculopathy. The development of a panel of blood biomarkers to monitor diabetic retinopathies is essential for both diagnosis and prognosis. Proteomics as a powerful tool for the analysis of complex mixtures of proteins and the identification of biomarkers can be of great importance. Purpose: To detect early nerve fiber layer changes around macula and optic disc in diabetic patients, and to correlate diabetic retinopathy with blood antioxidants and gut microbiota in T2DM in Saudi patients. Materials and Methods: In this cross-sectional case-control study, a total of 77 eyes of 39 subjects aged 40-60 years who did not have any history of eye injuries or eye diseases affecting fundus viewing, were recruited from King Saud University Campus and the department of ophthalmology in King Abdul Aziz university hospital in Riyadh. All subjects underwent full ophthalmic examination including Peripapillary retinal nerve fiber layer thickness and macular profile, Proteomic approach of collected overnight fasting plasma and Microbial stool examination. Results: The nerve fiber layer thickness around the optic disc was measured for all groups, and there was no statistically significant difference in all quadrants between groups. The total retinal thickness at the macular area was different among all groups and tends to increase in group 3 due to diabetic retinopathy. The macular thickness in the 4 quadrants revealed no statistical difference except in the inferior quadrant. Glutathione S transferase and lipid peroxides showed no significant difference between the three studied groups; vitamin C and Glutathione were surprisingly higher in controlled diabetic patients relative to controls. Moreover, over growth of bacteroids participated to the evolution of retinopathy in diabetic patients. Conclusion: As hyperglycemia and oxidative stress are implicated in the pathogenesis of diabetic retinopathy, the present study certified that the progressive damage can be delayed in controlled type 2 diabetic patients using different treatment modalities that subside oxidative stress.

Morphological differences of the neuroretinal rim between temporally tilted and non-tilted optic discs in healthy eyes

This study aimed to compare morphological differences of the neuroretinal rim between the temporally tilted and non-tilted optic discs in healthy eyes. We prospectively enrolled participants aged 20–40 years with temporally tilted or non-tilted optic discs. The optic nerve head parameters were analyzed using spectral domain-optical coherence tomography. The angle between the Bruch’s membrane opening (BMO) plane and BMO-minimum rim width (BMO-MRW) was termed “BMO-MRW angle”. Peripapillary retinal nerve fiber layer thickness (pRNFLT) and BMO-based parameters were compared between the temporally tilted and non-tilted disc groups. As a result, 55 temporally tilted disc eyes and 38 non-tilted disc eyes were analyzed. Global pRNFLT, global BMO-MRW, and total BMO-minimum rim area (BMO-MRA) were similar between the two groups (p = 0.138, 0.161, and p = 0.410, respectively). In the sectoral analysis, temporally tilted disc group exhibited thicker BMO-MRW in the temporal sector (p = 0.032) and thinner in the nasal superior and nasal sectors (p = 0.025 and p = 0.002, respectively). Temporally tilted disc group showed larger BMO-MRA in the temporal, temporal superior, and temporal inferior sectors (p < 0.001, p < 0.001, and p < 0.016, respectively), alongside a higher BMO-MRW angle in the temporal sector and lower in the nasal superior and nasal sectors. In conclusion, the neuroretinal rim, represented by BMO-MRW and BMO-MRA, showed morphological differences between temporally tilted and non-tilted optic discs in healthy eyes. BMO-MRW and BMO-MRA showed temporalization in the same manner as pRNFLT in the temporally tilted disc eyes. The BMO-MRW angle showed that in temporally tilted disc eyes, optic nerve fibers met the BMO plane steeply in the nasal sector and gently in the temporal sector than in non-tilted disc eyes, suggesting potential stress region of optic nerve fibers in temporally tilted disc eyes.

Clinical observation of the intraocular distribution characteristics of indocyanine green after epiretinal membrane peeling using a fluorescence detection system developed in Python

Objective: To utilize a Python-based fluorescence area detection system to observe and quantitatively analyze the intraocular distribution characteristics and metabolic patterns of Indocyanine Green (ICG) following epiretinal membrane peeling. Methods: A prospective case series study was conducted on patients with idiopathic epiretinal membrane undergoing vitrectomy at West China Hospital of Sichuan University from March 2019 to March 2021. ICG staining was applied during surgery for peeling the epiretinal membrane and internal limiting membrane. Patients were followed up at 1 week, 1 month, 3 months, 6 months, and 12 months postoperatively, with assessments including best-corrected visual acuity, intraocular pressure, fundus photography, near-infrared fundus fluorescence imaging (NIR-FF), and optical coherence tomography (OCT). A Python-based ICG intraocular metabolism detection system was developed to measure the residual area of ICG fluorescence on NIR-FF, predict the ICG metabolic pattern equation, and correlate it with postoperative visual acuity and peripapillary retinal nerve fiber layer thickness. Results: A total of 64 patients (64 eyes) were included, with an average age of 64.6±8.4 years, including 25 males (39.1%) and 39 females (60.9%). Preoperative NIR-FF images showed no ICG strong fluorescence. At 1 week postoperatively, diffuse ICG strong fluorescence appeared in the posterior pole, and the internal limiting membrane removal area exhibited a ring-like weak fluorescence. Over time, ICG strong fluorescence was observed along the vascular arch and nerve fiber trajectory, gradually diminishing toward the optic disc, with residual ICG fluorescence still visible at the optic disc at 1 year. The Python-based ICG fluorescence area detection system effectively measured intraocular residual ICG area. A predictive equation for the 12-month residual ICG area was constructed through linear regression analysis (Residual ICG area=0.22 × Residual ICG area at 6 months, R2=16%, P=0.002). Except for a negative correlation between the ICG residual area at 1 month and postoperative visual acuity (P=0.017, r=-0.195), no correlation was found between intraocular ICG fluorescence residual area and postoperative visual acuity or peripapillary retinal nerve fiber layer thickness at other follow-up times (all P>0.05). Conclusions: In patients with idiopathic epiretinal membrane undergoing ICG staining for internal limiting membrane peeling, ICG exhibits characteristic metabolic processes in the eye, with strong fluorescence along the vascular arch and nerve fiber trajectory, gradually converging toward the optic disc over time. The Python-based ICG fluorescence area detection system provides a clear display of the intraocular distribution characteristics of ICG after epiretinal membrane peeling and serves as a tool for predicting the metabolic patterns of ICG in the eye.

Untargeted and Oxylipin-Targeted Metabolomics Study on the Plasma Samples of Primary Open-Angle Glaucoma Patients.

Purpose: to determine the metabolomics profiles in the plasma samples of primary open-angle glaucoma (POAG) patients. Methods: The plasma samples from 20 POAG patients under intraocular pressure (IOP)-lowering medication treatment and 20 control subjects were subjected to the untargeted metabolomics analysis, among which 10 POAG patients and 10 control subjects were further subjected to the oxylipin-targeted metabolomics analysis by liquid chromatography-mass spectrometry analysis. The prediction accuracy of the differentially abundant metabolites was assessed by the receiver operating characteristic curves. Pathway analysis and correlation analysis on the differentially abundant metabolites and clinical and biochemical parameters were also conducted. Results: Untargeted metabolomics profiling identified 33 differentially abundant metabolites in the POAG patients, in which the metabolism of linoleic acid, α-linolenic acid, phenylalanine, and tricarboxylic acid cycle were enriched. The correlation analysis indicated that the differentially abundant metabolites were associated with central corneal thickness, peripapillary retinal nerve fiber layer thickness, visual field defects, and lymphocytes. The oxylipin-targeted metabolomics analysis identified 15-keto-Prostaglandin F2 alpha, 13,14-Dihydro-15-keto-prostaglandin D2, 11-Dehydro-thromboxane B2, 8,9-Epoxyeicosatrienoic acid, and arachidonic acid to be significantly decreased in the POAG patients and enriched in the arachidonic acid (AA) pathway. Conclusions: This study revealed that the metabolites in the arachidonic acid metabolism pathway are differentially abundant, suggesting high IOP may not be the only detrimental factor for optic nerve cell damage in this group of POAG patients. Lipid metabolism instability-mediated alterations in oxylipins and AA pathways may be important in POAG, suggesting that oxidative stress and immune-related inflammation could be valuable directions for future therapeutic strategies.

Papillary and peripapillary vascular densities and corresponding correlation with peripapillary retinal thicknesses using optical coherence tomography angiography in healthy children and adolescents

To evaluate the peripapillary retinal thickness (PPRT), vascular density (PPVD), and disc vascular density (PVD) and their correlations in normal healthy children using optical coherence tomography angiography (OCTA). This was a cross-sectional study of 70 eyes from 36 normal healthy children aged 6–18 years who performed optic nerve head scans using OCTA. The PPRT included the peripapillary nerve fiber layer (PP-RNFLT), inner retina (PP-IRT), middle retinal thickness, and outer retinal thicknesses. The PP-RNFLT and PP-IRT were not significantly different between males and females. Superior nasal peripapillary RNFLT and IRT were significantly affected by age (ANOVA, P > 0.05). The PP-IRT and PP-RNFLT were lower in the 7–11 years old group in comparison with the other 3 groups (Post hoc Tukey test, P value < 0.05). Age and sex-matched PVD were not correlated with PPVD (partial correlation, P > 0.05). PPRT was not correlated with PVD, PPVD, superficial and deep retinal vascular densities, and choroidal vascular density. This study demonstrated that PPRT appears to change during growth in childhood. Superior nasal PPRT was affected more in the groups, decreasing from less than 7 years old to 7–11 years old and then back to pre-reduction values after 11 years old.

Peripapillary retinal nerve fibre layer thinning, perfusion changes and optic neuropathy in carriers of Leber hereditary optic neuropathy-associated mitochondrial variants

BackgroundWe investigated Leber hereditary optic neuropathy (LHON) families for variation in peripapillary retinal nerve fibre layer thickness and perfusion, and associated optic nerve dysfunction.MethodA group of LHON-affected patients (n=12) and...

Avaliação do endotélio corneano através de microscopia especular em participantes com edema macular diabético

Introduction: While the morphological and functional integrity of the corneal endothelium, which is essential for corneal transparency, is affected by diabetes mellitus (DM), its relationship with the severity of diabetic retinopathy and the presence of diabetic macular edema is unclear. Aims: To assess the morphological characteristics of the corneal endothelium in patients with Type 2 Diabetes Mellitus (T2DM) with different therapeutic response profiles to diabetic macular edema (DME). Methods: With a cross-sectional approach, 24 participants with T2DM were divided into 2 groups (without DME versus with DME). Subsequently, the group with DME was subdivided according to the type of therapeutic response (responder versus persistent). Parameters obtained through specular microscopy (endothelial cell density, coefficient of variation, hexagonality, and central corneal thickness) and optical coherence tomography (minimum foveal thickness, central 1mm thickness, macular ganglion cell layer thickness, and peripapillary retinal nerve fiber layer thickness) were analyzed and compared in the different groups. Results: No significant changes were found in the corneal endothelium between the groups with and without DME (p&gt;0.05). However, differences were found in the density of endothelial cells (p=0.04) in participants with persistent DME (1900.3 ± 270.1) compared to participants with responding DME (2307.9 ± 121.2) and control group (2191.7 ± 165.5). Conclusion: There were no differences in the different parameters of the corneal endothelium between participants with and without DME. However, the kind of therapeutic response to DME seems to be associated with a decrease in endothelial cell density.

Effects of Deep Optic Nerve Head Structures on Bruch's Membrane Opening- Minimum Rim Width and Peripapillary Retinal Nerve Fiber Layer

PurposeTo explore the effects of deep optic nerve head (ONH) structures on Bruch's membrane opening (BMO)-minimum rim width (MRW) and peripapillary retinal nerve fiber layer thickness (pRNFLT) in healthy eyes. DesignProspective cross-sectional study MethodsTwo hundred five healthy eyes of 141 subjects (mean ± standard deviation of age and axial length (AXL): 46.9±10.0 years and 24.79±1.15 mm) were enrolled. Best fit multivariable linear mixed models identified factors associated with BMO-MRW and pRNFLT. Explanatory variables included age, sex, AXL, BMO and anterior scleral canal opening (ASCO) area and ovality, magnitude of BMO and ASCO shift, peripapillary choroidal thickness, lamina cribrosa (LC) parameters, prelaminar thickness and peripapillary scleral (PPS) angle. ResultsThinner BMO-MRW was associated with older age, smaller ASCO/BMO offset magnitude, larger BMO area, thinner prelaminar thickness, deeper LC, and thinner pRNFLT (p=0.011, <0.001, 0.004, <0.001, <0.001, <0.001 respectively). Thinner pRNFLT was associated with shorter AXL, smaller ASCO area, a more posteriorly bowed PPS, shallower LC and thinner BMO-MRW. (p=0.030, 0.002, 0.035, 0.012, <0.001 respectively) ConclusionsBMO-MRW and pRNFLT were influenced by several deep ONH structures such as BMO and ASCO position shift, BMO or ASCO area, prelaminar thickness, PPS bowing and LC depth in addition to patient characteristics such as age and AXL. The degree and/or direction of associations varied between deep ONH structures and BMO-MRW or pRNFLT. Despite both BMO-MRW and pRNFLT being surrogate parameters for RGC loss, a complex relationship with ONH deep-layer morphology was indicated.

Clinical Characteristics of Microcystic Macular Edema in Chronic Primary Angle-Closure Glaucoma and Primary Open-Angle Glaucoma Patients

Introduction: This study investigated the clinical characteristics of and risk factors for microcystic macular edema (MME) in patients with chronic primary angle-closure glaucoma (CPACG) and primary open-angle glaucoma (POAG). Methods: This retrospective observational study included 1,588 eyes from 926 glaucoma inpatients and analyzed the patients’ basic demographic information, visual field parameters, macular scans, and peripapillary retinal nerve fiber layer thickness. Results: Our findings were that the incidence rate of MME was 3.97% (34/857) in CPACG and 5.88% (43/731) in POAG. MME was predominantly diagnosed at an advanced stage in CPACG (almost 100%) compared to POAG (93.02%). MME was most frequently involved in the inferior (83.12%) quadrant of the peri-macular region in both CPACG and POAG. Risk factors for MME occurrence in CPACG and POAG included lower visual field mean deviation (OR = 1.14, 95%: CI 1.05-1.24, p = 0.003; OR = 1.14, 95% CI: 1.06–1.21, p < 0.001) and younger age (OR = 0.92, 95% CI: 0.88-0.96, p < 0.001; OR = 0.96, 95% CI: 0.93–0.99, p = 0.003), while female sex (OR = 0.30, 95% CI: 0.11–0.84, p = 0.022) reduced the MME occurrence in POAG. Conclusion: MME could develop in both CPACG and POAG patients, occurring earlier in POAG. The inferior peri-macular region is commonly affected. Younger age and poorer visual field are risk factors for MME in glaucoma patients.

Clinical Characteristics of Idiopathic Intracranial Hypertension in Older Adults.

Idiopathic intracranial hypertension (IIH) is a condition that classically affects obese women of child-bearing age. However, it is sometimes encountered in older patients. The purpose of this study was to help clinicians better understand how this disease can present differently in these age groups. This is a retrospective chart review from a single academic center of baseline characteristics of adult patients diagnosed with IIH based on the modified Dandy criteria. The patients were divided into 2 groups: (1) those 18-44 years old and (2) those older than 45 years at diagnosis. One hundred sixty-seven patients were identified; 135 in the younger group and 32 in the older group. The younger group had a higher rate of headaches (90% vs 63%, P = 0.0004), higher body mass index (38.9 vs 36.1, P = 0.046), higher opening pressure (38 vs 31 cm H2O, P = 0.005), and thicker peripapillary retinal nerve fiber layer average thickness (right eye 178 vs 131 μm, P = 0.02; left eye 184 vs 136 μm, P = 0.045). The older group had higher rates of empty sella (90% vs 62%, P = 0.0039). In addition in the younger group, there was a trend toward higher rates of pulsatile tinnitus (63% vs 45%, P = 0.08), transient visual obscurations (50% vs 32%, P = 0.07), and lower rates of spontaneous cerebrospinal fluid leak (4% vs 13%, P = 0.08). Sex, rates of obesity, other MRI findings typical of elevated intracranial pressure, frequency and Frisen grading of papilledema, and visual field loss were not statistically different between the groups. The older age group had milder signs and symptoms of IIH and a higher prevalence of empty sella than the younger group, but otherwise had typical characteristics. These findings suggest that IIH in the older age group may represent milder chronic disease that was previously undiagnosed.

Visualization of Optic Nerve Structural Patterns in Papilledema Using Deep Learning Variational Autoencoders.

To visualize and quantify structural patterns of optic nerve edema encountered in papilledema during treatment. A novel bi-channel deep-learning variational autoencoder (biVAE) model was trained using 1498 optical coherence tomography (OCT) scans of 125 subjects over time from the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) and 791 OCT scans of 96 control subjects from the University of Iowa. An independent test dataset of 70 eyes from 70 papilledema subjects was used to evaluate the ability of the biVAE model to quantify and reconstruct the papilledema spatial patterns from input OCT scans using only two variables. The montage color maps of the retinal nerve fiber layer (RNFL) and total retinal thickness (TRT) produced by the biVAE model provided an organized visualization of the variety of morphological patterns of optic disc edema (including differing patterns at similar thickness levels). Treatment effects of acetazolamide versus placebo in the IIHTT were also demonstrated in the latent space. In image reconstruction, the mean signed peripapillary retinal nerve fiber layer thickness (pRNFLT) difference ± SD was -0.12 ± 17.34 µm, the absolute pRNFLT difference was 13.68 ± 10.65 µm, and the RNFL structural similarity index reached 0.91 ± 0.05. A wide array of structural patterns of papilledema, integrating the magnitude of disc edema with underlying disc and retinal morphology, can be quantified by just two latent variables. A biVAE model encodes structural patterns, as well as the correlation between channels, and may be applied to visualize individuals or populations with papilledema throughout treatment.

Assessment of linear regression of peripapillary optical coherence tomography retinal nerve fiber layer measurements to forecast glacuoma trajectory.

Linear regression of optical coherence tomography measurements of peripapillary retinal nerve fiber layer thickness is often used to detect glaucoma progression and forecast future disease course. However, current measurement frequencies suggest that clinicians often apply linear regression to a relatively small number of measurements (e.g., less than a handful). In this study, we estimate the accuracy of linear regression in predicting the next reliable measurement of average retinal nerve fiber layer thickness using Zeiss Cirrus optical coherence tomography measurements of average retinal nerve fiber layer thickness from a sample of 6,471 eyes with glaucoma or glaucoma-suspect status. Linear regression is compared to two null models: no glaucoma worsening, and worsening due to aging. Linear regression on the first M ≥ 2 measurements was significantly worse at predicting a reliable M+1st measurement for 2 ≤ M ≤ 6. This range was reduced to 2 ≤ M ≤ 5 when retinal nerve fiber layer thickness measurements were first "corrected" for scan quality. Simulations based on measurement frequencies in our sample-on average 393 ± 190 days between consecutive measurements-show that linear regression outperforms both null models when M ≥ 5 and the goal is to forecast moderate (75th percentile) worsening, and when M ≥ 3 for rapid (90th percentile) worsening. If linear regression is used to assess disease trajectory with a small number of measurements over short time periods (e.g., 1-2 years), as is often the case in clinical practice, the number of optical coherence tomography examinations needs to be increased.

Neuro-ophthalmological changes in healthy females exposed to a 5-day dry immersion: a pilot study

After exposure to microgravity, astronauts undergo microgravity-induced thoraco-cephalic fluid shift, which may lead to ocular changes called “spaceflight associated neuro-ocular syndrome” (SANS). The onset of SANS may be multifactorial, including a potential elevation in intracranial pressure. Moreover, little is known about the impact of spaceflight on SANS in women due to the fact that fewer female astronauts have spent time in long-term missions. The objective is to determine whether similar ophthalmological changes occur in healthy women after short-term exposure to microgravity. The auto-refractometer was used to determine objective refraction. The best corrected distance visual acuity was assessed with a Monoyer chart. The ocular axial length was assessed using optical biometry. The applanation tonometry was used to determine intraocular pressure. Peripapillary retinal nerve fibre layer thickness (pRNFLT), macular total retinal thickness, and ganglion cell complex (GCC) were measured using optical coherence tomography. Ocular axial length is reduced after DI. pRNFL is thickest after DI specifically in the temporal, temporal-inferior, and nasal-inferior quadrants. Macular total retinal at the inferior quadrant of the 6-mm ring is thickest after DI. Global GCC is thinnest after DI. In this study, 5 days of DI induces slight but significant ophthalmological changes in women. However, these subtle changes do not correspond to criteria defined in SANS.

Longitudinal changes in the ganglion cell complex thickness in acute central serous chorioretinopathy using spectral-domain optical coherence tomography

In this retrospective longitudinal cohort study, we investigated the temporal changes in the peripapillary retinal nerve fiber layer (pRNFL) and inner retinal thickness in patients with acute central serous chorioretinopathy (CSC) using spectral-domain optical coherence tomography (SD-OCT). We followed up with these patients for 6 months, and during this period, the thickness of the pRNFL and the ganglion cell complex (GCC) in CSC patients were compared with the eyes of normal healthy individuals. The study also examined the correlation between the pRNFL thickness, GCC thickness, and visual acuity. The research sample consisted of 67 patients (43 male and 24 female) with an average age of 49.72 ± 9.87 years. The initial findings showed no significant differences in the pRNFL and GCC thickness between the study and fellow eye, study and normal healthy eyes, and fellow and normal healthy eyes. There was no significant difference in the pRNFL and GCC thickness when comparing the study eye with the fellow eye for 6 months. In the study eye, no significant difference was observed when comparing the initial GCC and pRNFL thickness with those at 1, 3, and 6 months. Visual acuity improved significantly from 0.18 ± 0.23 logMAR to 0.04 ± 0.06 logMAR (p < 0.001). The GCC and pRNFL thickness did not significantly affect visual acuity. In conclusion, acute CSC patients did not show significant changes in the pRNFL and inner retinal thickness, suggesting that the GCC and pRNFL do not substantially influence the short-term visual prognosis in these patients.

Progressive Changes in the Neuroretinal Rim and Retinal Nerve Fiber Layer in Glaucoma: Impact of Baseline Values and Floor Effects

ObjectiveTo determine whether more severe baseline damage impedes measurement of minimum rim width (MRW) and peripapillary retinal nerve fibre thickness (RNFLT) change in glaucoma patients because of a floor effect. DesignProspective longitudinal cohort study in a hospital-based setting. SubjectsThe study included patients with open-angle glaucoma and healthy control subjects. Participants had at least 5 years of follow-up with optical coherence tomography every 6 months. MethodsBaseline global and sectorial MRW and RNFLT values were classified as within normal limits, borderline, or outside normal limits based on reference normative values. Regression analysis was used to determine the magnitude and significance of MRW and RNFLT change. Additionally, the follow-up period for each participant was divided into two equal halves (1st and 2nd periods) to determine whether there was attenuation of MRW and RNFLT change with follow-up time. Main Outcomes MeasuresRates of global and sectoral MRW and RNFLT changes (slopes). ResultsA total of 97 patients with glaucoma (median age, 70.3 years) and 42 healthy subjects (median age, 64.8 years) were followed for a median of 6.9 years and 7.0 years, respectively. The median mean deviation of visual field test for glaucoma patients was -4.30 dB (interquartile range: -7.81 to -2.06 dB, range: -20.68 to 1.37 dB). Statistically significant changes in global and sectoral MRW and RNFLT were detected across all baseline classifications, however, there was tendency for less change with increasing baseline damage. In glaucoma patients, RNFLT slopes, but not MRW slopes, were significantly more positive (less change) in the 2nd period compared to the 1st. There were also no differences in either MRW or RNFLT slopes in the 1st and 2nd periods in healthy subjects. Conclusions and RelevanceSignificant MRW and RNFLT changes were detected at all levels of baseline damage. However, an attenuation in the rate of RNFLT change compared to MRW indicate an earlier floor effect in RNFLT measurements globally and in equivalent sectors. Because the axonal component of these measurements should be equivalent, our results suggest important differences in tissue remodelling at the level of the optic nerve head and peripapillary retina.