Mean Retinal Nerve Fiber Layer Research Articles

Accelerated Epigenetic Aging is Associated with Faster Glaucoma Progression: A DNA Methylation Study.

To investigate the association between epigenetic age acceleration and glaucoma progression. Retrospective cohort study. 100 primary open-angle glaucoma (POAG) patients with fast progression and 100 POAG patients with slow progression. Subjects were classified as fast or slow progressors based on rates of change in standard automated perimetry (SAP) mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness. Epigenetic age was calculated using the Horvath, Hannum, PhenoAge, and GrimAge clocks from DNA methylation profiles obtained from blood samples. Age acceleration (AgeAccel) was defined as the residual from a linear regression of epigenetic age on chronologic age, with positive values suggesting faster biological aging. Multivariable logistic regression models estimated the association between AgeAccel and likelihood of fast progression, adjusting for confounders. Difference in epigenetic age acceleration between fast and slow glaucoma progressors. The mean rate of SAP MD change in the fastest progressing eye was -1.06 dB/year (95% CI: -1.28 to -0.85) for fast progressors compared to -0.10 dB/year (95% CI: -0.16 to -0.04) for slow progressors (P<0.001). For RNFL thickness, corresponding values were -1.60 μm/year (95% CI: -1.97 to -1.23) and -0.76 μm/year (95% CI: -1.04 to -0.48), respectively (P<0.001). Fast progressors demonstrated significantly greater age acceleration compared to slow progressors for the Horvath clock (mean difference = 2.93 years, 95% CI: 1.48 to 4.39, P<0.001) and Hannum clock (mean difference = 1.24 years, 95% CI: 0.03 to 2.46, P=0.045). In multivariable models, each year of Horvath AgeAccel was associated with 15% higher odds of fast progression (OR 1.15, 95% CI 1.07-1.23, P<0.001), after adjusting for sex, race, intraocular pressure, central corneal thickness, baseline disease severity, smoking status and follow-up time. Hannum and GrimAge clocks also showed significant associations with fast progression. The association between AgeAccel and fast progression was stronger in subjects with relatively low IOP during follow-up. Accelerated epigenetic aging was associated with faster glaucoma progression. These findings suggest that faster biological age, as reflected in DNA methylation, may increase optic nerve susceptibility to damage, highlighting epigenetic age as a potential prognostic biomarker.

Five-year changes in retinal nerve fibre layer thickness in the adult population: a population-based cohort study.

Distinguishing between the pathological thinning of the retinal nerve fibre layer (RNFL) and age-related reduction requires a comprehensive understanding of the longitudinal changes in RNFL thickness within a healthy population. To determine five-year changes in RNFL thickness and associated factors in people aged 45-69 years. This report pertains to the second and third phases of the Shahroud Eye Cohort Study. Participants were recruited by a multi-stage cluster sampling in Shahroud, Iran. Data on demographic details, visual acuity, non-cycloplegic refraction, and slit-lamp biomicroscopy were collected. High-definition optical coherence tomography was employed for retinal imaging. A total of 1,524 eyes from 908 participants were examined. The average RNFL thickness was 92.2 ± 8.5 (95% CI: 91.6 to 92.8) and 93.1 ± 8.7 μm (95% CI: 92.5 to 93.7) in the first and second phases with a five-year mean change of 0.95 ± 4.15 μm (95% CI: 0.70 to 1.20). The RNFL thickness mean changes in the superior, inferior, nasal, and temporal quadrants were 2.51 ± 7.86 (95% CI: 2.01 to 3.02), 2.93 ± 7.39 (95% CI: 2.56 to 3.29), -0.53 ± 6.15 (95% CI: -0.84 to -0.21), and -1.01 ± 4.67 μm (95% CI: -1.27 to -0.75), respectively. The five-year changes in average RNFL thickness were inversely correlated with axial length (β = -0.69, p < 0.001), mean keratometry (β = -0.37, p = 0.017), and baseline RNFL thickness (β = -0.617, p < 0.001). In hyperopic individuals, the increase in average RNFL thickness (β = 0.65, p = 0.012) was significantly greater than in those with emmetropia. Macular volume (β = 1.65, p < 0.001) showed a direct association with five-year changes in average RNFL thickness. Over 5 years, RNFL thickness changes were clinically insignificant in the normal population. The mean RNFL thickness seems to remain stable unless there is ocular disease. However, increased axial length and steeper keratometric readings were linked to RNFL thinning. Those with thicker RNFL measurements were at higher risk of thinning over time.

Clinical follow-up investigation on thickness changes in the peripapillary retinal nerve fibre layer of patients with Leber hereditary optic neuropathy

BackgroundTo investigate the peripapillary retinal nerve fibre layer (RNFL) thickness changes and analyse factors associated with visual recovery of G11778A Leber hereditary optic neuropathy (LHON) patients.MethodsPatients diagnosed with G11778A LHON between July 2017 and December 2020 in Tongji hospital were included in this follow-up study. Patients were grouped according to disease duration. Variations in the RNFL thickness in each quadrant at different disease stages were characterised using optical coherence tomography. According to the absence or presence of significant visual acuity improvements, LHON patients of disease duration ≥ 6 months were divided into two groups. A bivariate logistic regression model was constructed to analyse the potential factors associated with spontaneous visual recovery.ResultsThis study included 56 G11778A LHON patients (112 eyes) and 25 healthy controls (50 eyes), with a mean follow-up of 5.25 ± 1.42 months. All quadrants and mean RNFL thicknesses of LHON patients first increased and then decreased, except for the temporal RNFL. As the disease progressed, RNFL thinning slowed; however, gradual RNFL thinning occurred. Logistic regression revealed that baseline best corrected visual acuity was related to spontaneous visual recovery of LHON patients with disease duration ≥ 6 months.ConclusionThe pattern of RNFL involvement could be helpful in the differential diagnosis of LHON and other optic neuropathies. LHON patients with better vision are more likely to experience some degree of spontaneous visual acuity recovery after the subacute phase.

Differences in Systemic Pulse Waveform Between Individuals With Glaucoma, Glaucoma Suspects, and Healthy Controls.

It has been hypothesized that compromised ocular circulation in glaucoma may be concomitant of systemic changes. The purpose of this study is to test whether systemic blood flow pulse waveform patterns differ between individuals with glaucoma (GL), glaucoma suspects (GLS), and normal healthy controls (HC). The study included 35 bilateral GL, 67 bilateral GLS, 29 individuals with unilateral GL who were considered GLS in the other eye, and 44 healthy controls. Systemic pulsatile blood pressure waveforms were recorded using a finger cuff. A continuous 200Hz plethysmography recording is made to obtain a pulse waveform. Waveform parameters were extracted using custom software from an average of eight pulse cycles. These were compared between GL, GLS, and HC groups on a per-eye basis, using generalized estimating equation models to account for intereye correlations; and plotted against disease severity by visual field linearized mean deviation (MDlin) and retinal nerve fiber layer thickness (RNFLT). Averaged blood pressure was significantly lower in the HC group (mean ± standard deviation 91.7 ±11.7 mm Hg) than the GLS (102.4 ± 13.9) or GL (102.8 ± 13.7) groups, with P < 0.0001 (generalized estimating equation regression). Waveform parameters representing vascular resistance were higher in both GLS and GL groups than the HC group; and were correlated with RNFLT and MDlin (P ≤ 0.05). The shape of the systemic pulsatile waveform differs in individuals with GL/GLS suspects, compared to HC eyes. Blood pressure changes more rapidly in individuals with GL, which suggests higher arterial stiffness.

An assessment of the thickness of the retinal nerve fiber layer around the optic disc using spectral domain optical coherence tomography in myopia patients at an industrial hospital in India

Myopia is rising as a silent epidemic across the globe with marked ocular morbidity and pathological changes. The retinal nerve fiber layer (RNFL) thinning is indicative of glaucomatous damage; it remains uncertain whether RNFL thickness would vary with the refractive status of the eye. It is therefore important to investigate whether any correlation exists between RNFL measurements and axial length/refractive error in myopia. Purpose. To assess the peripapillary RNFL thickness by spectral domain optical coherence tomography (SD-OCT) and to determine the correlation between axial length and peripapillary RNFL thickness in myopia patients. Material and methods. A total of 100 patients (200 eyes) with low, moderate and high myopia (ave -3.58 ± 2.45 D) aged 15 to 40 years were examined to assess the peripapillary RNFL thickness by SD-OCT and to determine the correlation between axial length (AL) and peripapillary RNFL thickness myopia patients. Results. Average 360-degree RNFL thickness (mean ± SD) was 92.25 ± 10.04 μm. In the low myopic group this parameter was 98.82 ± 6.67 μm, in the moderate myopic group — 89.28±5.23 μm, and in the high myopic group — 78.54 ± 7.32 μm. The average 360-degree mean RNFL thickness in patients with AL &lt; 24 mm was 100.06 ± 5.92 μm, in patients with AL between 24–26 mm — 89.48 ± 4.59 μm, and in patients with AL &gt; 26 mm — 78.2 ± 6.77 μm. There was significant association between thinning of the average 360-degree RNFL thickness with increasing degree of myopia and AL (p &lt; 0.0001). Conclusion. The study shows RNFL thickness decreases with increase in refractive error and increase in axial length of myopic eyes. The degree of myopia may affect the RNFL thickness differently.

Rates of retinal nerve fiber layer loss in early-stage pseudoexfoliation and primary open-angle glaucoma patients using optical coherence tomography.

To characterize glaucoma progression in early-stage patients with retinal nerve fiber layer (RNFL) using the change analysis software (CAS), which was utilized to track RNFL thinning. We retrospectively analyzed 92 eyes of 92 patients with early-stage glaucoma. Patients were divided into two subgroups based on their diagnosis of pseudoexfoliation glaucoma (PEG) and primary open-angle glaucoma (POAG). A complete ophthalmologic examination was performed on all patients. Additionally, automated perimetry was conducted on each patient. Furthermore, Fourier-domain optical coherence tomography (OCT) was employed to measure RNFL and central corneal thickness. Using the OCT device's CAS, we computed the annual rate of total and glaucomatous RNFL thinning for each patient. A total of 44 PEG and 48 POAG patients were included in the study. The right eye measurements of these patients were analyzed and compared. The two groups were not significantly different in age, gender, and the number of visits per year (p > 0.05, for each). However, the difference between the mean RNFL thickness at baseline (91.39 ± 10.71 and 96.9 ± 8.6µm) and at the last visit (85.2 ± 15.76µm and 91.56 ± 9.58µm) was statistically significant between the two groups (p = 0.043, p = 0.039, respectively). Additionally, the difference in annual RNFL thinning rates (1.43 ± 0.81µm and 1.07 ± 0.32µm) between the two groups was statistically significant (p = 0.009). The annual rate of glaucomatous RNFL loss in early-stage PEG patients (1.23µm) was higher than in POAG patients (0.87µm). However, despite these loss rates, scotoma was not detected in the visual field tests of these patients. Therefore, using CAS in the follow-up of early-stage glaucoma patients is a useful alternative for monitoring glaucomatous progression. Furthermore, this method can be utilized in future research for the diagnosis and follow-up of glaucoma in special populations (e.g., those with pathological myopia or high hyperopia) that are not included in normative databases.

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.

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

To determine the associations between social vulnerability index (SVI) and baseline severity, worsening, and variability of glaucoma, as assessed by visual field (VF) and OCT. Retrospective longitudinal cohort study. Adults with glaucoma or glaucoma suspect status in 1 or both eyes. Visual fields were derived from 7897 eyes from 4482 patients, while OCTs were derived from 6271 eyes from 3976 patients. All eyes had a minimum of 5 tests over follow-up using either the Humphrey Field Analyzer or the Cirrus HD-OCT. Social vulnerability index, which measures neighborhood-level environmental factors, was linked to patients' 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 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 intraocular pressure (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 standard deviation of the residuals obtained from MD and RNFL slopes. Increased (worse) SVI was significantly associated with worse baseline MD (β=-1.07 dB, 95% confidence interval [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 SVI 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. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

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.

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.