Retinal Nerve Fiber Layer In Eyes Research Articles

Comparison of Retinal Nerve Fiber Layer Thickness Between Mild to Moderately Myopic Eyes with Normal Eyes

Aim: To access the difference between the mean thickness of the retinal nerve fiber layer (RNFL) in myopic eyes (down to -6.00 D) and the normal eye. Study Design: An Observational and Descriptive study. Place duration: In the department of Ophthalmology, Al Shifa Trust Eye Hospital, Rawalpindi for six-months duration from June 2020 to November 2020. Methods: In this study, the mean comparison of RNFL among 70 myopic eyes (down to -6.00 D) and 70 normal eyes of the same age was done. 15-45 years was the patients’ age range. A comprehensive eye exam was performed and thickness of RNFL was evaluated by optical coherence tomography. Data analysis was done with t-test for independent samples using SPSS 21.0; p <0.05 as the significant value. Results: The RNFL mean variation between both groups was 5.901 µm (SE: 1.930). The mean RNFL thickness in the group of people with myopia was 96.31 ± 11.121 µm with (SE: 1.310) and mean age was 28.32 ± 7.452 years. The mean thickness of RNFL was 94.210 ± 9.521 µm in the right eye and 99.175 ± 11.142 µm in the left eye. The RNFL mean score of thickness for eyes with myopia distributed normally as p <0.04. The RNFL mean score of thickness for normal group was (102.81 ± 11.48 µm) with (SE: 1.40), and the mean thickness of RNFL evaluated in healthy eyes did not show a normal distribution as P <0.20. This study outcomes exhibited a statistically substantial variance between the mean thickness of RNFL assessed in myopic and normal eyes (p <0.003). Conclusion: There is a significant variation in mean thickness of RNFL between normal and myopic eyes as assessed by optical coherence tomography. Appropriate understanding of data of RNFL in eyes with myopia is suggested to evade glaucoma misdiagnosis. Keywords: Optical coherence tomography, Myopia and Thickness of the Retinal Nerve Fiber Layer.

OCT angiography, RNFL and the visual field at different values of intraocular pressure.

The aim of the present study was to investigate the relationship between intraocular pressure (IOP), vessel density (VD), retinal nerve fiber layer (RNFL) parameters and overall defect (OD) of the visual field in eyes where antiglaucoma treatment had not yet been initiated. A total of 61 subjects (122 eyes) who had an IOP of >20 mmHg on several occasions, in at least one eye, in routine outpatient care were included. These were subjects who had never been treated for hypertension glaucoma. The cohort was divided into four subgroups. In the first group, there were 18 eyes with an IOP value of <20 mmHg. In the second group, there were 39 eyes with IOP values of 20-22 mmHg. The third group consisted of 32 eyes with IOP values of 22-24 mmHg and the final group consisted of 33 eyes with IOP values of >24 mmHg. The IOP results were compared with VD, RNFL and OD using Pearson's correlation coefficient to assess the relationship between the selected parameters. RNFL and OD were moderately correlated only in the group of eyes with an IOP value >24 (r=0.48); in the other groups the correlation was very weak. However, changes in visual field were already observed in eyes with IOP 20-22 mmHg (r=-0.27). There was a moderate correlation in eyes with an IOP value >24 mmHg (r=-0.53). The most significant result observed was the relationship between VD and RNFL. In eyes with an IOP value ≤20, a moderate to strong correlation between these parameters was observed. This relationship increased with increasing IOP values up to a very strong correlation in the group with an IOP value >24 mmHg. A moderate to strong dependence between VD and RNFL in eyes with an IOP value ≤20 mmHg was observed, and this dependence was very strongly correlated in the eyes with an IOP value >24 mmHg.

Comparison of Rate of Change between Bruch's Membrane Opening Minimum Rim Width and Retinal Nerve Fiber Layer in Eyes Showing Optic Disc Hemorrhage

To investigate and compare the longitudinal rate of change of Bruch's membrane opening minimum rim width (BMO-MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness in eyes showing optic disc hemorrhage(DH). Observational case series. A total of 82 subjects(82 eyes) showing DH who had undergone more than five reliable spectral-domain optical coherence tomography (OCT) tests were included. BMO-MRW and RNFL were measured with OCT at 3-month intervals. The rates of change in global and each Garway-Heath sector were calculated with a linear mixed-effects model after adjusting for age, sex, and BMO area. The mean follow-up period was 21.57 ± 7.88months with a mean number of 7.88 ± 2.39 OCT tests. Baseline demographics were age (58.37 ± 10.65 y); 46.3% were female; and the mean deviation was-4.41 ± 5.04 dB. The global rate of change in BMO-MRW was-3.507 ± 0.675μm/y and in-1.404 ± 0.208μm/y in RNFL. The rate of change was the greatest in the inferotemporal sector, which was-9.141 ± 1.254μm/y in BMO-MRW and-4.204 ± 0.490μm/y in the RNFL. The rate of change was significantly greater in BMO-MRW than in the RNFL in all sectors, except for the nasal sector (P < .05). Percentage of reduction was significantly greater in BMO-MRW than in RNFL in the inferotemporal and superotemporal sectors (P < .05). BMO-MRW showed a significantly greater rate of change than RNFL in eyes showing DH, especially in the inferotemporal and superotemporal sectors in percentage of reduction. Thus, it may be more advantageous to detect glaucomatous progression earlier in BMO-MRW than in the RNFL in eyes showing DH that are more likely to progress.

Peripapillary Retinal Nerve Fiber Measurement with Spectral-Domain Optical Coherence Tomography in Age-Related Macular Degeneration

Purpose: To evaluate the relationship between the peripapillary retinal nerve fiber layer (RNFL) measurements with Spectral-domain Optical Coherence Tomography (OCT) and Age-related macular degeneration (AMD). Methods: Patients >60 years of age without glaucoma or record of intraocular pressure >21 mmHg and no systemic or intraocular diseases or treatment or surgical intervention that affected the RNFL underwent OCT measurement of the RNFL. The severity of AMD was staged with the Clinical Age-Related Maculopathy Staging System. The relationship between RNFL measurements and AMD stages of one eye per patient was analyzed. Results: Eighty-six eyes (46 patients) with AMD and no glaucoma or other exclusion criteria received OCT RNFL measurements. Nine eyes (10.5%) were excluded because of distorted peripapillary anatomy from exudative AMD (7 eyes) or failure of the RNFL segmentation algorithm (2 eyes). Mean age ± S.D. of the 43 patients analyzed was 81.2 ± 7.3 years. The mean stage ± S.D. of AMD of the 77 eyes was 3.77 ± 1.05. Higher stages of AMD were statistically significantly associated with lower average RNFL and inferior sector RNFL (p = 0.049, 0 0015, respectively). The association of inferior sector RNFL and AMD stage remained statistically significant after adjusting for age. Conclusions: Spectral domain OCT is generally useful in measuring the peripapillary RNFL in eyes with different stages of AMD. Higher stage of AMD is associated with thinner peripapillary RNFL, which may masquerade as early glaucomatous damage.

Peripapillary Retinal Nerve Fiber Layer Vascular Microcirculation in Eyes With Glaucoma and Single-Hemifield Visual Field Loss

Understanding the differences in vascular microcirculation of the peripapillary retinal nerve fiber layer (RNFL) between the hemispheres in eyes with glaucoma with single-hemifield visual field (VF) defects may provide insight into the pathophysiology of glaucoma. To investigate the changes in the microcirculation of the peripapillary RNFL of eyes with glaucoma by using optical microangiography. Eyes with glaucoma and single-hemifield VF defect and normal eyes underwent scanning using an optical microangiography system covering a 6.7 × 6.7-mm2 area centered at the optic nerve head. The RNFL microcirculation was measured within an annulus region centered at the optic nerve head divided into superior and inferior hemispheres. Blood flux index (the mean flow signal intensity in the vessels) and vessel area density (the percentage of the detected vessels in the annulus) were measured. Differences in microcirculation between the hemispheres in eyes with glaucoma and normal eyes and correlations among blood flow metrics, VF thresholds, and clinical optical coherence tomography structural measurements were assessed. Twenty-one eyes from 21 patients with glaucoma (7 men and 14 women; mean [SD] age, 63.7 [9.9] years) and 20 eyes from 20 healthy control individuals (9 men and 11 women; mean [SD] age, 68.3 [10.7] years) were studied. In eyes with glaucoma, the abnormal hemisphere showed a thinner RNFL (mean [SE] difference, 23.5 [4.5] μm; 95% CI, 15.1-32.0 µm; P < .001), lower RNFL blood flux index (mean [SE] difference, 0.04 [0.01]; 95% CI, 0.02-0.05; P < .001), and less vessel area density (mean [SE] difference, 0.08% [0.02%]; 95% CI, 0.05%-0.10%; P < .001) than did the normal hemisphere. Compared with normal eyes, reduced RNFL microcirculation was found in the normal hemisphere of eyes with glaucoma, measured by mean [SE] differences in blood flux index (0.06 [0.01]; 95% CI, 0.04-0.09; P < .001) and vessel area density (0.04% [0.02%]; 95% CI, 0.02%-0.08%; P = .003) but not in RNFL thickness (3.4 [4.7] μm; 95% CI, -6.2 to 12.9 µm; P = .48). Strong correlations were found between the blood flux index and VF mean deviation (Spearman ρ = 0.44; P = .045) and RNFL thickness (Spearman ρ = 0.65; P = .001) in the normal hemisphere of the eye with glaucoma. Reduced RNFL microcirculation was detected in the normal hemisphere of eyes with glaucoma, with strong correspondence with VF loss and RNFL thinning. Although the results suggest that vascular dysfunction precedes structural changes seen in glaucoma, longitudinal studies would be needed to confirm this finding.

Glaucoma Diagnostic Ability of the New Circumpapillary Retinal Nerve Fiber Layer Thickness Analysis Based on Bruch's Membrane Opening.

To compare the diagnostic ability of the new spectral-domain optical coherence tomography (SD-OCT) algorithm for measuring circumpapillary retinal nerve fiber layer (RNFL) thickness centered on Bruch's membrane opening (BMO), with the conventional circumpapillary RNFL thickness measurement centered on the optic disc. In 75 eyes with primary open-angle glaucoma (POAG) and 71 healthy control eyes, circumpapillary RNFL thickness was measured with SD-OCT, first by centering the scan circle on the optic disc (RNFLDi), and then on the BMO (RNFLBMO). Difference between the topographic profiles of RNFLDi and RNFLBMO was compared and factors influencing any discrepancies between methods were investigated. Glaucoma diagnostic abilities of each method were assessed using the areas under receiver operating characteristic curve (AUCs). Axial length did not differ between POAG and healthy eyes. A longer axial length and larger width of externally oblique border tissue (BT) associated with tilted optic disc were the two major factors influencing discrepancies between RNFLBMO and RNFLDi (both P < 0.001). Compared with RNFLBMO, RNFLDi tended to result in a thinner nasal RNFL in eyes with externally oblique BT, while RNFLBMO and RNFLDi were comparable in eyes without externally oblique BT. The glaucoma diagnostic capabilities were generally comparable, but RNFLBMO was superior to RNFLDi in eyes having a larger width (>250 μm) of externally oblique BT (AUC = 0.933 vs. 0.843, respectively, P = 0.027). The new circumpapillary RNFL scanning algorithm centered on BMO may provide a more reliable RNFL profile in eyes with tilted optic discs, with a largely comparable glaucoma diagnostic ability to the conventional algorithm.

Retinal nerve fiber layer configuration in eyes with epiretinal membrane.

To characterize configurations of the optic nerve head (ONH) and peripapillary retinal nerve fiber layer (RNFL) eyes with epiretinal membrane (ERM). We reviewed medical records of consecutive patients with ERM who were examined between September 2012 and August 2013. Patients were categorized based on the severity of ERM on fundus imaging; patients with ERM but without retinal distortion were in group 1, and patients with ERM and retinal distortion were in group 2. Optic nerve head and RNFL parameters measured by spectral domain optical coherence tomography were assessed and compared between eyes with ERM and normal fellow eyes. There were no significant differences in ONH and RNFL parameters between ERM eyes and normal fellow eyes in group 1 (n = 12). In group 2 (n = 33), cup volume was smaller (p = 0.020), temporal quadrant RNFL thickness was greater by 18.8 ± 16.6 μm (p < 0.001), and RNFL peak angle was smaller by 18.7 ± 25.3 degrees in ERM eyes compared with fellow eyes (p = 0.001). In the 15 patients in group 2 who underwent ERM removal, temporal quadrant RNFL thickness decreased and the RNFL peak angle increased after the surgery (p = 0.008 and p = 0.001, respectively). The configurations of the ONH and peripapillary RNFL in eyes with ERM were different from those in fellow eyes. The characteristic configurations of RNFL such as small peak angle and temporal quadrant thickening may be considered when evaluating parameters as measured by spectral domain optical coherence tomography.

Retinal Nerve Fiber Layer Thickness, Brain Atrophy, and Disability in Multiple Sclerosis Patients

To study the relationship between retinal nerve fiber layer (RNFL) thickness and brain atrophy using magnetic resonance imaging (MRI) with bicaudate ratio (BCR) in patients with multiple sclerosis (MS) with different levels of disease severity. We also assessed whether RNFL thickness correlated with Expanded Disability Status Scale (EDSS) score. The participants consisted of 88 patients with MS and 59 age- and sex-matched healthy control subjects. Eleven patients had clinically isolated syndrome (CIS), 68 patients had relapsing-remitting MS (RR-MS), and 9 patients had secondary progressive MS. Patients and controls were evaluated using optical coherence tomography (OCT, Cirrus) and scanning laser polarimetry with variable corneal compensation (GDx VCC). Patients underwent the same brain MRI scanning protocol. Disability was evaluated according to the EDSS. The BCR was calculated by dividing the minimum intercaudate distance by brain width along the same level. The BCR was higher in patients with MS (0.12 ± 0.03) than in controls (0.08 ± 0.009) (P < 0.001). OCT average RNFL thickness in patients with MS was significantly lower (84.51 ± 14.27 μm) than in control subjects (98.44 ± 6.83 μm). BCR was correlated with OCT average RNFL thickness (r = -0.48, P = 0.002) in patients with MS without optic neuritis. Significant correlations were found between average RNFL thickness and EDSS (r = -0.43, P = 0.003). Additionally, there were correlations between BCR with GDx parameters in patients with MS without optic neuritis. This study shows that RNFL thickness correlates with BCR and with MS subtypes. Additionally, our study indicates that OCT is better suited for MS assessment than GDx. We conclude that the damage of retinal axons appears related to brain damage in patients with MS.

Quantitative assessment of optic disc edema using spectral domain optical coherence tomography

Introduction Optic disc edema (ODE) can be caused by a variety of conditions including pseudotumor cerebri, hypertension, diabetes, uveitis, anemia, lymphoma, and papillitis. Improvement in the quality of optical coherence tomography (OCT) can support the diagnosis and management of ODE. OCT may help in this diagnosis by showing peripapillary retinal nerve fiber layer (RNFL) thickening. Aim of the work To evaluate quantitative assessment of optic disc edema by measuring peripapillary nerve fiber layer (RNFL) thickness, and peripapillary maximum neurosensory retinal (MNSR) thickness in the four quadrants using spectral domain OCT. Patients and methods The study was done in El-Minya Investigation Eye Center between May 2012 and May 2013. The study included 21 eyes of 16 patients with optic disc edema and 20 eyes of 11 normal control persons. Both patients and normal control were examined by spectral domain OCT, two sets of measurements were evaluated and compared: Peripapillary RNFL thickness measurement in four quadrants using the standard optic disc cube 200 × 200 acquisition protocol, spectral domain OCT, Peripapillary maximum neurosensory retinal thickness (MNSR) in four quadrants using high definition 5 line images. Results In ODE group, 21 eyes of 16 patients were evaluated. The control group included 20 eyes of 11 normal subjects. The Mean average peripapillary RNFL was 93.1 ± 8.2 in control group 132.3 ± 46 µ in mild ODE, 139.4 ± 29.2 µ in moderate ODE and 264.2 ± 116.9 µ in severe ODE. The mean average peripapillary MNSR in the four quadrants was 350.1 ± 36.3 µm in control group, 458.7 ± 37.3 µm in mild ODE, 634.4 ± 35.01 µm in moderate ODE and 968.3 ± 245 µm in severe ODE. Conclusion There was a statistically significant increase in mean RNFL thickness and mean MNSR in four quadrants in all grades of ODE group compared with the control group ( P = 0.001). There was a strong positive correlation ( r = 0.89, P = 0.001) between the mean MNSR and the mean RNFL in eyes with ODE.

Retinal Nerve Fiber Layer Thickness in Patients with Exfoliation, Exfoliative Glaucoma, and Primary Open Angle Glaucoma

to evaluate the retinal nerve fiber layer(RNFL) profile of healthy controls, persons with exfoliation syndrome (XFS), and patients with exfoliation glaucoma (XFG) and primary open angle glaucoma(POAG). One eye from each of 269 participants was analyzed. Fifty eyes were normal , 45 eyes had XFS, 89 eyes had POAG, and 89 had XFG. Glaucoma patients were divided according to the severity of the disease into mild and advanced groups. All participants underwent imaging with the GDx-VCC device. Measurements of the parameters TSNIT average, TSNIT SD, and nerve fiber indicator (NFI) were performed. Polametric RNFL thickness values were compared by means of Bonferroni-corrected t-tests. Regarding control and glaucoma groups, statistically significant differences were identified in all GDx parameters. RNFL thickness values of the control group differed significantly from the values of the XFS group. There was no statistically significant difference between RNFL thickness values for the mild POAG and mild XFG groups or for the advanced POAG and advanced XFG groups. Polarimetry-determined RNFL in eyes with XFS is thinner than that of healthy eyes. No differences in RNFL thickness were found when eyes with POAG and XFG of similar severity were compared.

Optical coherence tomography in optic neuritis and multiple sclerosis: a review

Optical coherence tomography (OCT) is a new noninvasive high-resolution method that measures the retinal nerve fiber layer (RNFL) thickness. An overview of the use in optic neuritis (ON) and multiple sclerosis (MS) is presented. Literature survey of PubMed was carried out. RNFL thickness in eyes of healthy control subjects was 102.9-111.11 microm, in eyes affected by ON 59.79-85 microm, and in fellow eyes 82.73-99.8 microm. All studies found a significant reduction in RNFL in eyes affected by ON compared with fellow eyes and eyes of healthy controls. Two out of three studies found a significant reduction in RNFL in fellow eyes compared with control eyes. RNFL thickness correlated with visual acuity, visual field, low-contrast letter acuity, contrast sensitivity, and color vision. Correlations were also found with the optic nerve area evaluated by magnetic resonance imaging, neurologic impairment score, and increasing disease duration. One of two studies found a significant correlation with amplitudes of visual evoked potentials, neither correlated with latencies. OCT is a promising new tool for evaluating atrophy in patients with ON and MS.