Significant Retinal Nerve Fiber Layer Thinning Research Articles

Clinical efficacy of dexamethasone parabulbar injection in patients with Nonarteritic anterior ischemic optic neuropathy

BackgroundNonarteritic anterior ischemic optic neuropathy (NAAION) is a common optic neuropathy that often leads to significant visual acuity loss in patients. The present study evaluated the effects of parabulbar dexamethasone injection on visual outcomes in patients with NAAION. MethodsThis retrospective case-control study included patients diagnosed with NAAION between January 2019 and December 2022. Thirty-four patients with NAAION (34 eyes) received dexamethasone parabulbar injections, while 39 patients with NAAION (39 eyes) received oral corticosteroid treatment (control group). Best-corrected visual acuity (BCVA), visual field (VF) defect, and retinal nerve fiber layer (RNFL) thickness of the affected eye were compared between groups at baseline and 2, 6, and 12 weeks post-treatment. ResultsMean BCVA significantly improved after 6 and 12 weeks in the injection groups compared with the control group (all P < 0.01). The visual field indices, mean deviation and pattern standard deviation significantly improved in the injection group compared with the control group after 2, 6, and 12 weeks (all P < 0.01). The RNFL showed a remarkable decrease in edema after 6 weeks (superior and nasal P values 0.005 and 0.013, respectively) in the injection group compared with the control group. Significant RNFL thinning was also observed in superior, inferior, temporal, and nasal quadrants in the control group after 12 weeks (all P values < 0.01). Also, fewer side effects were observed in the injection group compared to the control group. ConclusionsThe results of this study suggested that dexamethasone parabulbar injection might be a safe and effective intervention for relieving visual acuity and VF in patients with NAAION.

Longitudinal Changes in the Retinal Nerve Fiber Layer Thickness in Amyotrophic Lateral Sclerosis and Parkinson's Disease.

There is increasing evidence that the anterior visual pathways are involved in neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). This study investigated longitudinal changes in retinal nerve fiber layer (RNFL) thickness in patients with ALS and PD with the aim of better understanding their roles as biomarkers of disease progression. This study recruited 21 ALS patients, 19 age-matched PD patients, and 21 agematched healthy controls. Patient demographics and clinical scores relating to the respective diseases were documented. The RNFL thickness was measured using optical coherence tomography at baseline and after 6 months. At baseline, the RNFL in the superior quadrant was significantly thinner in the patients with ALS than in healthy controls (109.90±22.41 µm vs. 127.81±17.05 µm [mean±standard deviation], p=0.008). The RNFL thickness did not differ significantly between the ALS and PD patients or between the PD patients and healthy controls. At 6 months, there was further significant RNFL thinning in patients with ALS, for both the overall thickness (baseline: median=94.5 µm, range=83.0-106.0 µm; follow-up: median=93.5 µm, range=82.5-104.5 µm, p=0.043) and the thickness in the inferior quadrant (median=126 µm, range=109.5-142.5 µm; and median=117.5 µm, range=98.5-136.5 µm; respectively, p=0.032). However, these changes were not correlated with the ALS functional scores. In contrast, the patients with PD did not demonstrate a significant change in RNFL thickness between the two time points. The RNFL thickness is a promising biomarker of disease progression in patients with ALS but not in those with PD, which has a slower disease progression.

Leber Hereditary Optic Neuropathy Gene Therapy: Longitudinal Relationships Among Visual Function and Anatomical Measures

To assess longitudinal relationships among visual function and anatomical measures of gene therapy in G11778A Leber hereditary optic neuropathy (LHON). Phase 1 clinical trial. This was a single-institution study of patients with G11778A LHON. Patients with chronic bilateral visual loss >12 months (group 1, n=11), acute bilateral visual loss <12 months (group 2, n=9), or unilateral visual loss (group 3, n=8) were administered unilateral intravitreal AAV2(Y444,500,730F)-P1ND4v2 injection with low, medium, high, and higher doses to worse eye for groups 1 and 2 and better eye for group 3. Oucome measures were best-corrected visual acuity (BCVA), visual field mean deviation (VF MD), steady-state pattern electroretinogram (SS-PERG), optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness and ganglion cell+inner plexiform layer (GCIPL) thickness, and National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) scores. Mean follow-up was 33.6 months (range=18-36 months). Baseline SS-PERG amplitude was much reduced in both eyes of all groups including asymptomatic eyes of group 3, and showed no appreciable changes irrespective of disease stage and treatment. Significant and progressive GCIPL and RNFL thinning occurred in all eyes; BCVA and VF MD fluctuated in treated and fellow eyes, with some eyes having modest improvement that may be related to natural history or to gene therapy. Mean NEI-VFQ-25 scores declined in group 3 subjects (P=.023), CONCLUSION: Asymptomatic eyes in LHON patients with unilateral visual loss may be beyond the window of effective neuroprotection given reduced GCIPL and SS-PERG. Randomization of patients to an untreated control group would help to assess treatment effect by accounting for variable natural history. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Longitudinal change of peripapillary vessel density and retinal nerve fibre layer thickness in normal tension and primary angle closure glaucoma

PurposeTo compare the rates of peripapillary vessel density (pVD) loss and retinal nerve fibre layer (RNFL) thinning in normal tension glaucoma (NTG) and primary angle closure glaucoma (PACG).MethodsBaseline age and...

Corneal endothelium, retinal nerve fiber layer, ganglion cell complex, and perimetry measurements in normal eyes and those with primary open-angle glaucoma.

Corneal endothelial cell (CEC) loss in glaucoma can be attributed to the direct compressive effect of elevated intraocular pressure. Herein, we aimed to evaluate specular microscopic changes in CEC count and morphology in correlation to retinal nerve fiber layer (RNFL) changes detected by spectral-domain optical coherence tomography (SD-OCT) in early and advanced primary open-angle glaucoma (POAG). This descriptive-analytical study involved patients with medically controlled POAG versus non-glaucomatous patients of the same age group. Specular microscopy, visual field testing, and SD-OCT of the RNFL and macular ganglion cell complex (GCC) were performed. Eyes with POAG were further subcategorized into early and advanced stages. The study included 130 eyes of 130 participants; 70 were eyes with POAG (40 eyes with early-stage POAG, 30 eyes with advanced-stage POAG), and 60 were healthy eyes. The groups were comparable regarding mean age and sex. No significant difference was found in corneal parameters between healthy eyes, eyes with early POAG, and eyes with advanced POAG (all P > 0.05). In eyes with early-stage POAG, a significant negative correlation was found between the coefficient of variation (CV) and superior RNFL thickness (r = - 0.5; P = 0.018), and between the percentage of hexagonal cells (hexagonality) and vertical cup-to-disc ratio (r = - 0.43; P = 0.035). A significant positive correlation was found between hexagonality and superior as well as inferior RNFL thickness (r = + 0.53; P = 0.008 and r = + 0.50; P = 0.015, respectively). However, in the advanced glaucomatous eyes, no significant correlation was found between RNFL thickness and CEC parameters. CEC parameters were not affected in eyes with early or advanced POAG compared with healthy eyes, despite a significant thinning of RNFL and macular GCC. In eyes with early-stage POAG, a significant correlation was found between morphological characteristics of CECs, such as CV and hexagonality, with superior and inferior RNFL thickness in the optic nerve head on SD-OCT images. Future longitudinal studies with larger sample sizes are needed to verify our results.

Quantitative analysis of related parameters of retinal nerve fiber layer and ganglion cell complex thickness in patients with different degrees of Parkinson's disease.

A quantitative analysis was performed to evaluate the morphologic changes of the retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) in patients with Parkinson's disease (PD). Thirty PD patients were enrolled, and they were allocated to the mild-to-moderate PD group (n = 15) or severe PD group (n = 15) according to the severity of PD. Twenty healthy volunteers (20 eyes) were included as controls. Optical coherence tomography (OCT) was used to measure the thickness of mean RNFL and each of the sectors: temporal-upper (TU), superior-temporal (ST), superior-nasal (SN), nasal-upper (NU), nasal-lower (NL), inferior-nasal (IN), inferior-temporal (IT), temporal-lower (TL). The thickness of macular GCC, superior GCC, and inferior GCC was also measured. No difference was found between the three groups with respect to age, sex and disease course (p > 0.05). The mean RNFL thickness was 118.15 ± 10.25µm in the control group, 96.12 ± 9.45µm in the mild-to-moderate PD group, and 80.48 ± 10.35µm in the severe PD group. Significant differences were found in the mean RNFL thickness and thickness of TU, IN, IT and TL sectors among the three groups (p < 0.05). These values, mean RNFL, TU, IN, IT, and TL, were lower in both the PD groups than those in the control, among them the severe PD group had the lowest values. A quantitative analysis of the macula GCC was also performed. Overall, there were significant differences in mean macula, superior, and inferior GCC thickness among the three groups (p < 0.05). The two PD groups had lower values of mean macula, superior, and inferior GCC thickness than that in the controls (p < 0.05); and the severe PD group had lowest values of these parameters. In this study, significant thinning of RNFL and macular GCC was found in PD patients. The more serious the illness, the more the thickness becomes thinner. The OCT measurement was found useful in detecting the structural alterations in the retina of PD. The technique may be useful in follow-up of the disease progression after further validation.

Analysis of retinal vasculature changes in indirect traumatic optic neuropathy using optic coherence tomography angiography.

To assess the retinal vasculature alterations in indirect traumatic optic neuropathy (ITON) patients following craniofacial trauma by optic coherence tomography angiography (OCTA). Patients diagnosed of monocular ITON were recruited from August 2016 to May 2020. OCTA was performed using the AngioVue OCT-A system for two cube scans centered at the optic nerve head and fovea. OCTA data included thicknesses of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC), as well as proportion of capillary perfusion and data were analyzed for correlation with post-injury timepoints: within 7, 8-30, 31-90, and 91-365d. A total of 73 ITON patients were studied. Significant thinning of RNFL and GCC layers and attenuation of microvascular perfusion were observed in ITON eyes as compared to contralateral unaffected eyes (for most of the analyzed sectors and quadrants, P<0.05). Without respect to surgical intervention and vision recovery, the decrease in retinal layer thicknesses and microvascular perfusion was time-dependent, and most significant within three months (P<0.001). ITON presents with time-dependent thinning of retinal layers and attenuation of microvasculature, indicating possible degeneration of retinal ganglion cells due to reduced retinal blood supply.

Selective and Inverse U-Shaped Curve Alteration of the Retinal Nerve in Amyotrophic Lateral Sclerosis: A Potential Mirror of the Disease.

Introduction: Alterations in the visual pathway involving the retina have been reported in amyotrophic lateral sclerosis (ALS) but they lack consistency and subgroup analysis. We aimed to assess the retinal nerve fiber layer (RNFL) and retinal ganglion cells (RGCs) alterations in different stages of ALS patients and their association with ALS progression parameters.Methods: The study population consisted of 70 clinically diagnosed ALS patients and 55 age, sex matched controls. All of them underwent ophthalmic assessments and optical coherence tomography imaging. Four quadrants of the peripapillary RNFL and ganglion cell/inner plexiform complex (GCIP) were observed and automatically measured. Early-stage distal motor neuron axon dysfunction in ALS was detected by compound muscle action potential (CMAP) of the distal limbs within 12 months. The ALS disease parameters included the ALSFRS-R score and the disease progression rate (ΔFS).Results: Generally compared with controls, the nasal (p = 0.016) quadrant of the RNFL was thicker in ALS patients. When controlling for age and ΔFS, the RNFL(r = 0.37, p = 0.034) and GCIP(r = 0.40, p = 0.021) were significantly thickened as disease progressed within 12 months, while the RNFL declined with time after one year (r = −0.41, p = 0.037). ALS patients was subclassified into thickened RNFL (T-RNFL, >95th percentile of normal), impaired RNFL (I-RNFL, <5th percentile of normal) and normal RNFL. There were significant differences in the GCIP among the three groups (p < 0.001). In the T-RNFL group (n = 18), the RNFL was negatively correlated with the abductor pollicis brevis-CMAP amplitude within 12 months (r = −0.56, p = 0.01). Patients within 12 months in this group progressed faster than others (p = 0.039). In the normal RNFL group (n = 22), 13 patients were diagnosed beyond 12 months, whose ΔFS was remarkably lower (p = 0.007). In I-RNFL group (n = 30), the early stage patients (<12 months) had significant higher ΔFS (p = 0.006). One patient was with SOD1 pathogenic variant (p.A5V).Conclusion: Alterations of retinal nerve were not consistent in ALS patients with diverse phenotypes and progression rates. Generally speaking, the RNFL thickened during the first year and then gradually declined, which is related to but preceding the thickness change of the RGCs. Patients with a significant RNFL thinning in the early stage may have a faster progression rate. The inverse U-shaped curve transformation might be in accordance with early-stage motor neuron axonopathy.

Delayed follow‐up of glaucoma patients due to COVID‐19 pandemic – impact on disease progression

AbstractPurposeTo determine the impact of delayed follow‐up on the disease course in patients with glaucoma.MethodsA retrospective case series of 224 glaucoma patients. Data analysis from the hospital electronic medical record was performed on patients attending the glaucoma clinic between April and May 2021 at Charing Cross Hospital, London, United Kingdom, after easing of the national lockdown due to COVID‐19 pandemic. The main outcome measures included increased intraocular pressure (IOP), worsening of visual field (VF) defect, thinning of retinal nerve fibre layer (RNFL) and the posterior pole using spectral domain Optical Coherence Tomography (OCT).ResultsNotes from 224 patients were analysed. Among them, 24 patients were identified to develop a progression of glaucoma. Majority of patients (10, 42%) had open angle glaucoma, 6 (25%) had normal tension glaucoma, 5 (21%) were glaucoma suspects, 2 (8%) had narrow angle glaucoma and 1 (4%) had angle closure glaucoma. The mean IOP (±SD) pre‐lockdown was 15.4 ± 3.8 mmHg and post‐lockdown was 16.7 ± 5.4 mmHg (p &lt; 0.05). The average RNFL thickness pre‐lockdown was 79.7 ± 15.7 µm and post‐lockdown was 78.8 ± 15.6 µm (p &gt; 0.05). Of the 24 patients who developed progression, 16 had an increase in IOP (mean ∆ IOP was 3.8 ± 1.8 mmHg; p &lt; 0.05), 19 patients had a clinically significant RNFL thinning (mean ∆ was 3.3 ± 1.4 µm; p &lt; 0.05) and 9 patients had worsening of VF. The average timing between pre‐ and post‐lockdown visit was 15.1 months (SD ± 7.6).ConclusionsThese results confirm that a proportion of patients developed glaucoma progression during the COVID Lockdown which could be attributed to delayed follow‐up. Further analyses of these data will be needed to confirm how the results of this study could help to guide future decisions making and guidance on prioritising and managing glaucoma patients if disruption to standard of care occurs.

Longitudinal Assessment Using Optical Coherence Tomography in Patients with Friedreich’s Ataxia

Ocular abnormalities occur frequently in Friedreich’s ataxia (FRDA), although visual symptoms are not always reported. We evaluated a cohort of patients with FRDA to characterise the clinical phenotype and optic nerve findings as detected with optical coherence tomography (OCT). A total of 48 patients from 42 unrelated families were recruited. Mean age at onset was 13.8 years (range 4–40), mean disease duration 19.5 years (range 5–43), mean disease severity as quantified with the Scale for the Assessment and Rating of Ataxia 22/40 (range 4.5–38). All patients displayed variable ataxia and two-thirds had ocular abnormalities. Statistically significant thinning of average retinal nerve fibre layer (RNFL) and thinning in all but the temporal quadrant compared to controls was demonstrated on OCT. Significant RNFL and macular thinning was documented over time in 20 individuals. Disease severity and visual acuity were correlated with RNFL and macular thickness, but no association was found with disease duration. Our results highlight that FDRA is associated with subclinical optic neuropathy. This is the largest longitudinal study of OCT findings in FRDA to date, demonstrating progressive RNFL thickness decline, suggesting that RNFL thickness as measured by OCT has the potential to become a quantifiable biomarker for the evaluation of disease progression in FRDA.

Retinal nerve fiber layer thickness in multiple sclerosis with and without optic neuritis: a four-year follow-up study from Oman

BackgroundMultiple sclerosis (MS) is an autoimmune disease that attacks the central nervous system, with optic neuritis (ON) being a common early manifestation. Retinal nerve fiber layer (RNFL) thickness may be a biomarker of neuroaxonal damage in MS patients. We sought to evaluate changes in RNFL thickness over 4 years in Omani MS patients with or without ON in comparison to a healthy control group.MethodsThis retrospective case-control study involved 27 MS patients and 25 healthy controls. Optical coherence tomography was performed upon first diagnosis and at a four-year follow-up. Differences in mean RNFL thickness were calculated.ResultsA total of 51 eyes from the MS group and 50 eyes from the control group were evaluated. There was a significant reduction in mean RNFL thickness among MS patients with ON at follow-up (81.21 versus 72.14 μm; P = .003), whereas no significant RNFL thinning was observed among MS patients without ON. However, there was a significant reduction in RNFL thickness among MS patients compared to healthy controls (76.79 versus 93.72 μm; P = .009), regardless of ON presence/absence.ConclusionsAxonal damage was seen in the optic nerves of Omani MS patients. Moreover, there was a significant reduction in RNFL thickness among MS patients with ON as the disease progressed; however, while there was evidence of RNFL thinning in MS patients without ON, this difference lacked statistical significance. Evaluation of RNFL thickness may represent a useful biomarker for monitoring disease progression in MS and its association with ON.

Diagnostic Value of Optical Coherence Tomography and Electroretinogram in Early Detection of Ethambutol-Induced Optic Neuropathy

Background: Ethambutol-induced optic neuropathy (EON) is one of the most compelling adverse effect of tuberculosis treatment. Recovery often occur several months after treatment discontinuation. Unfortunately, some studies noted that nearly half of patients still have permanent visual loss. Early detection before clinical symptoms appear is necessary to prevent this devastating adverse effect. Therefore, this review aims to evaluate the diagnostic value of retinal nerve fiber layer (RNFL) thickness and ganglion cell inner plexiform layer (GCIPL) thickness changes with OCT, pattern and multifocal electroretinogram (ERG) changes during ethambutol treatment as early detection of EON. Methods: A comprehensive search was conducted from electronic databases (PubMed, EBSCO, Google Scholar, and Springerlink) using relevant search terms. Articles from offline resources were also included. Included studies were selected based on predefined inclusion and exclusion criteria. Result: Three studies reported significant thinning of RNFL after ethambutol initiation. Increased RNFL thickness in patients with EON and subclinical EON found in 3 studies. Significant macular GCPIL thinning was noted in 1 study. One study reported shortening of P50 implicit time and reduced N95 wave amplitude in pattern ERG. Conclusion: Macular GCIPL thinning suggested to be the first pathological changes detected on patients with ethambutol treatment. It can be concomitant with thickening of peripapillary RNFL and followed by peripapillary RNFL thinning. Pattern ERG may reveal abnormality due to retinal ganglion cell (RGC) dysfunction before RGC loss.

Neuroretinal Biomarkers for Schizophrenia Spectrum Disorders.

PurposeWe evaluated the patient-control differences and predictive value of the retina as potential biomarkers for schizophrenia.MethodsThe institutional study included both eyes of 58 schizophrenia spectrum disorder (SSD) patients (age 37.2 ± 12.3 years) and 35 controls (age 41.1 ± 15.2 years). Retinal nerve fiber layer (RNFL), ganglion cell–inner plexiform layer, outer retinal photoreceptor complex, and total macula thicknesses were measured by optical coherence tomography (OCT). Anterior segment parameters including central corneal thickness, anterior chamber depth, and axial length were measured to rule out confounds on the retinal measures.ResultsThe peripapillary RNFL was overall significantly thinner in SSD relative to controls (F = 3.97, P = 0.049), most pronounced in the temporal (5.2 µm difference, F = 6.95, P = 0.010) and inferior quadrants (12.1 µm difference, F = 7.32, P = 0.009). There were no significant group differences in thickness for the macular RNFL, ganglion, or photoreceptor cell related measures (P > 0.05). Peripapillary RNFL, central macula, and outer photoreceptor complex thicknesses were together able to classify SSD patients with 80% sensitivity and 71% specificity; area under the curve = 0.82 (95% confidence interval, 0.75–0.88).ConclusionsSSD patients exhibited significant RNFL thinning relative to controls. Notably, retinal thickness measures including both peripapillary and macular data exhibited improved diagnostic accuracy for SSD as compared to these regions alone.Translational RelevanceThis is the first study to evaluate the predictive value of both the inner and outer retina in SSD. OCT retinal thickness measures including peripapillary data in conjunction with macular data may provide an informative, noninvasive in vivo ocular biomarker for schizophrenia.

Segmented retinal analysis in pituitary adenoma with chiasmal compression: A prospective comparative study.

Purpose:The aim of this study was to determine the alteration in ganglion cell complex and its relationship with retinal nerve fiber layer (RNFL) thickness as measured by spectral-domain optical coherence tomography (OCT) in pituitary adenoma cases and also its correlation with visual field (VF).Methods:This is a prospective comparative study wherein detailed neuro-ophthalmic examination including perimetry, RNFL and ganglion cell layer inner plexiform layer (GCL-IPL) thickness were measured preoperatively in the cases of pituitary adenoma with chiasmal compression with visual symptoms and field changes who were planned for neuro-surgical intervention. These parameters were repeated 1 year after the surgery. GCL-IPL, RNFL parameters were compared with controls and were correlated with VF mean deviation (MD). The diagnostic power of GCL-IPL was tested using the receiver operating characteristic (ROC) curve. Healthy age and sex-matched controls without any ocular and systemic abnormality were taken for comparison.Results:Twenty-four patients qualified the inclusion criteria. A significant thinning of GCL-IPL (P = 0.002) and RNFL (P = 0.039) was noticed in the pituitary adenoma group. GCL-IPL (r = 0.780 P < 0.001) and RNFL (r = 0.669, P < 0.001) were significantly correlated with the MD. The ROC curve values of GCL-IPL were 0.859 (95% confidence interval 0.744% to 0.973) and of RNFL were 0.731 (95% confidence interval 0.585–0.877). The diagnostic ability of GCL-IPL was more as compared to the RNFL analysis, although it was statistically insignificant (P = 0.122).Conclusion:GCL-IPL measurements on the OCT are a sensitive tool to detect early anterior visual pathway changes in chiasmal compression for pituitary adenoma patients.

Enhanced Depth Imaging Optical Coherence Tomography Technology Reveals a Significant Association Between Optic Nerve Drusen Anterior Displacement and Retinal Nerve Fiber Layer Thinning Over Time.

Optic disc drusen (ODD) are a dynamic phenomenon, and their appearance, size, and relative location may change. The purpose of this study is to evaluate and quantify the longitudinal changes of buried ODD with enhanced depth imaging (EDI) optical coherence tomography (OCT) over time. ODD were analyzed with Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany) and EDI technology. The peripapillary retinal nerve fiber layer (RNFL) thickness was also measured. The size and depth of ODD were compared between the baseline and study visit (at least 2 years of follow-up), and the changes were correlated with mean RNFL thickness. The repeatability, coefficient of variation, and cutoff values for size and depth on EDI-OCT were calculated. Of 21 previously identified patients with ODD, only 12 patients (21 eyes) met the most recent diagnostic criteria according to the ODD Studies Consortium recommendations for using OCT-EDI technology. The 21 eyes were reanalyzed after a mean period of 44.7 ± 13.2 months (range: 24-71 months). Overall, 132 ODD were evaluated with a mean of 6.1 ± 2.5 ODD per eye and 1.9 ± 1.1 ODD per scan. Overall, we found a significant forward movement of the drusen between visits (P = 0.01). Most drusen (67.4%) moved anteriorly, and in approximately one-third (35.6%), this displacement exceeded the cutoff value (64.28 µm). Furthermore, we found a significant correlation between ODD shallowing and RNFL thinning during the follow-up (P ≤ 0.03; R ≥ 0.370). We did not find any significant changes in size measurements (P = 0.10) over time. In approximately one-third of buried ODD, a significant anterior movement occurred over 2 years of follow-up, and this movement was associated with significant RNFL thinning. By contrast, no significant change was detected in the size of the buried ODD.

Age-dependent regional retinal nerve fibre changes in SIX1/SIX6 polymorphism

SIX1/SIX6 polymorphism has been shown to be associated with glaucoma. Studies have also found that, in older adults, retinal nerve fibre layer (RNFL) thickness is significantly thinned with each copy of the risk allele in SIX1/SIX6. However, it is not known whether these genetic variants exert their effects in younger individuals. Comparing a healthy young adult with an older adult cohort (mean age 20 vs 63 years), both of Northern European descent, we found that there was no significant RNFL thinning in each copy of the risk alleles in SIX1/SIX6 in the eyes of younger individuals. The older cohort showed an unexpectedly thicker RNFL in the nasal sector with each copy of the risk allele for both the SIX1 (rs10483727) and SIX6 (rs33912345) variants. In the temporal sector, thinner RNFL was found with each copy of the risk allele in rs33912345 with a decrease trend observed in rs10483727. Our results suggest that SIX1/SIX6 gene variants exert their influence later in adult life.

MS optic neuritis-induced long-term structural changes within the visual pathway.

BackgroundThe visual pathway is commonly involved in multiple sclerosis (MS), even in its early stages, including clinical episodes of optic neuritis (ON). The long-term structural damage within the visual compartment in patients with ON, however, is yet to be elucidated.ObjectiveOur aim was to characterize visual system structure abnormalities using MRI along with optical coherence tomography (OCT) and pattern-reversal visual evoked potentials (VEPs) depending on a single history of ON.MethodsTwenty-eight patients with clinically definitive MS, either with a history of a single ON (HON) or without such history and normal VEP findings (NON), were included. OCT measures comprised OCT-derived peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell/inner plexiform layer (GCIPL) thickness. Cortical and global gray and white matter, thalamic, and T2 lesion volumes were assessed using structural MRI. Diffusion-weighted MRI-derived measures included fractional anisotropy (FA), mean (MD), radial (RD), and axial (AD) diffusivity within the optic radiation (OR).ResultsMean (SD) duration after ON was 8.3 (3.7) years. Compared with the NON group, HON patients showed significant RNFL (p = 0.01) and GCIPL thinning (p = 0.002). OR FA (p = 0.014), MD (p = 0.005), RD (p = 0.007), and AD (p = 0.004) were altered compared with NON. Global gray and white as well as other regional gray matter structures did not differ between the 2 groups.ConclusionA single history of ON induces long-term structural damage within the retina and OR suggestive of both retrograde and anterograde neuroaxonal degeneration.

Relationship between preoperative high intraocular pressure and retinal nerve fibre layer thinning after glaucoma surgery

Recent reports show varying results regarding peripapillary retinal nerve fibre layer (RNFL) thickness after intraocular pressure (IOP)-lowering glaucoma surgery. We hypothesised that different levels of the preoperative IOP influence RNFL thickness. A total of 60 patients (60 eyes) with glaucoma, who underwent glaucoma surgery and had a stable postoperative mean IOP < 22 mmHg, were enrolled. The RNFL thickness was measured using spectral domain optical coherence tomography, before and at 3–6 months after surgery. The preoperative peak IOP, 37.4 ± 10.8 mmHg, decreased to a postoperative mean IOP of 14.8 ± 3.5 mmHg (p < 0.001). The average RNFL thickness was significantly reduced from 75.6 ± 17.7 μm to 70.2 ± 15.8 μm (p < 0.001). In subgroup analyses, only patients with a preoperative peak IOP ≥ median value (37 mmHg) exhibited significant RNFL thinning (9.7 ± 6.6 μm, p < 0.001) associated with a higher preoperative peak IOP (r = 0.475, p = 0.008). The RNFL thinning was evident for a few months after glaucoma surgery in patients with a higher preoperative peak IOP, although the postoperative IOP was stable.

Clinical correlation of retinal nerve fiber layer thickness in multiple sclerosis patients- A North Indian study

Background: Axonal loss is thought to occur early in the course multiple sclerosis (MS) and is supposed to be associated with, and predictive of, neurologic deficits progressing to permanent disability.Axonal loss in the retinal nerve fiber layer (RNFL) is measured by optical coherence tomography (OCT). Material and Methods: A longitudinal observational study, conducted on 30 MS patients. All subjects underwent neurological examination, including expanded disability status scale (EDSS) scoring and OCT on two visits, minimum 2 months apart. Results: Total of 60 eyes of 30 patients were subdivided into 21 eyes having optic neuritis (ON) [‘MS – ON’] and 39 eyes without ON. The RNFL thickness (RNFLt) was found to be significantly reduced in all parameters except in temporal quadrant, as the duration of disease increases. Average RNFLt were found to have negative correlation (r = -0.450) with disease duration. Negative correlation (r=-0.657) was also found between EDSS score change and average RNFLt change. The eyes having ON showed statistically significant RNFL thinning as compared to the non – ON fellow eyes. The baseline EDSS score was found to be negatively correlated (moderate degree, r = -0.348) with baseline average RNFL thickness, with p-value of 0.006. Conclusions: The RNFLt is not only significantly thinner in those with history of ON, but it is also affected remarkably even in absence of prior ON, suggesting subclinical ongoing axonal loss in patients with MS. The EDSS score is inversely correlated with RNFL thickness.

Ganglion cell layer thinning in prodromal Alzheimer's disease defined by amyloid PET

IntroductionThe objective of this study was to investigate and compare optic nerve and retinal layers in eyes of patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) with paired control eyes using optical coherence tomography. MethodsSixty-three eyes of 34 subjects, 12 eyes with AD and 51 eyes with MCI, positive to 11C-labeled Pittsburgh Compound-B with positron emission tomography (11C-PiB PET/CT), and the same number of sex- and age-paired control eyes underwent optical coherence tomography scanning analyzing retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), Bruch's membrane opening–minimum rim width (BMO-MRW), inner plexiform layer (IPL), outer nuclear layer, and lamina cribrosa (LC). ResultsCompared with healthy controls, eyes of patients with positive 11C-PiB PET/CT showed a significant thinning of RNFL (P < .028) and GCL (P < .014). IPL and outer nuclear layer also showed significant thinning in two (P < .025) and one location (P < .010), respectively. No significant differences were found when optic nerve measurements BMO-MRW and LC were compared (P > .131 and P > .721, respectively). Temporal sector GCL, average RNFL, and temporal sector RNFL also exhibited significant thinning when MCI and control eyes were compared (P = .015, P = .005 and P = .050, respectively), and also the greatest area under the curve values (0.689, 0.647, and 0.659, respectively). GCL, IPL, and RNFL tend to be thinner in the AD group compared with healthy controls. DiscussionOur study suggests that RNFL and GCL are useful for potential screening in the early diagnosis of AD. LC and BMO-MRW appear not to be affected by AD.