Lower Retinal Nerve Fiber Layer Thickness Research Articles

Structure and Function Relationship of Activated Retinal Glia in Primary Open-Angle Glaucoma Patients.

Purpose To evaluate clinically activated retinal astrocytes and Müller cells (ARAM) regarding retinal sensitivity and retinal nerve fiber layer (RNFL) thickness in primary open-angle glaucoma (POAG). Methods Central visual field (VF; i.e., retinal sensitivity) was measured with a custom-made macular pattern by microperimetry and correlated with the presence (ARAM+) or absence (ARAM−) of ARAM on red-free fundus photography and with the corresponding RNFL by optical coherence tomography (OCT). Results In the eyes of POAG patients, ARAM+ had overall a significantly lower retinal sensitivity (ARAM+: 7.34 dB, ARAM−: 11.9 dB; p < 0.001) and lower RNFL thickness in the inferior peripapillary quadrants compared to ARAM− (RNFL superior: ARAM+ 74.2 μm, ARAM− 77.5 μm; RNFL temporal: ARAM+ 46.8 μm, ARAM− 53.0 μm, p < 0.001; and RNFL inferior: ARAM+ 63.2 μm, ARAM− 73.1 μm, p < 0.001). Within the same eye, ARAM+ showed a lower retinal sensitivity compared to ARAM− ([ARAM− (11.13 dB)] − [ARAM+ (9.56 dB) = 1.57 dB; p = 0.25). The proportion of ARAM+ per eye correlated strongly with reduced retinal light sensitivity (p = 0.02), corresponding lower peripapillary RNFL thickness (p = 0.02), and lower RNFL temporal quadrant thickness (p < 0.01), but not with greater age (p = 0.45). Conclusion ARAM was more frequently identified in the eyes with a lower retinal sensitivity and peripapillary RNFL thickness and may be a clinical sign in the macula for an advanced stage of POAG.

Optic pathway glioma volume predicts retinal axon degeneration in neurofibromatosis type 1.

To determine whether tumor size is associated with retinal nerve fiber layer (RNFL) thickness, a measure of axonal degeneration and an established biomarker of visual impairment in children with optic pathway gliomas (OPGs) secondary to neurofibromatosis type 1 (NF1). Children with NF1-OPGs involving the optic nerve (extension into the chiasm and tracts permitted) who underwent both volumetric MRI analysis and optical coherence tomography (OCT) within 2 weeks of each other were included. Volumetric measurement of the entire anterior visual pathway (AVP; optic nerve, chiasm, and tract) was performed using high-resolution T1-weighted MRI. OCT measured the average RNFL thickness around the optic nerve. Linear regression models evaluated the relationship between RNFL thickness and AVP dimensions and volume. Thirty-eight participants contributed 55 study eyes. The mean age was 5.78 years. Twenty-two participants (58%) were female. RNFL thickness had a significant negative relationship to total AVP volume and total brain volume (p < 0.05, all comparisons). For every 1 mL increase in AVP volume, RNFL thickness declined by approximately 5 microns. A greater AVP volume of OPGs involving the optic nerve and chiasm, but not the tracts, was independently associated with a lower RNFL thickness (p < 0.05). All participants with an optic chiasm volume >1.3 mL demonstrated axonal damage (i.e., RNFL thickness <80 microns). Greater OPG and AVP volume predicts axonal degeneration, a biomarker of vision loss, in children with NF1-OPGs. MRI volumetric measures may help stratify the risk of visual loss from NF1-OPGs.

Dyschromatopsia in Multiple Sclerosis Patients: A Marker of Subclinical Involvement?

In multiple sclerosis (MS), even in the absence of a clinical episode of optic neuritis (ON), the optic nerve and retinal nerve fiber layer (RNFL) may be damaged leading to dyschromatopsia. Subclinical dyschromatopsia has been described in MS associated with lower motor and cognitive performances. To set the prevalence of dyschromatopsia in eyes of MS patients without a history of ON, to compare its prevalence in patients with and without ON history, and to explore the association between dyschromatopsia and disease duration, average peripapillary RNFL thickness, macular volume, and cognitive and motor performances. An observational cross-sectional study was conducted at multiple medical centers. Data were collected after single neurological and ophthalmological evaluations. Dyschromatopsia was defined by the presence of at least 1 error using Hardy-Rand-Rittler plates. In our population of 125 patients, 79 patients (63.2%) never had ON and 35 (28.8%) had unilateral ON. The prevalence of dyschromatopsia in eyes of patients without ON was 25.7%. Patients with dyschromatopsia had a statistically significant lower RNFL thickness (P = 0.004 and P = 0.040, right and left eyes, respectively) and worse performance in symbol digit modalities test (P = 0.012). No differences were found in macular volume or motor function tasks. Dyschromatopsia occurs frequently in MS patients. It may be associated with a worse disease status and possibly serve as a marker for the detection of subclinical disease progression since it was detected even in the absence of ON. It correlated with thinner peripapillary RNFL thickness and inferior cognitive performance.

Retinal Nerve Fiber Layer Thickness in Children With ADHD

Objectives: The current study aims to compare retinal nerve fiber layer (RNFL) thickness, macular thickness, and macular volume between children with ADHD and a control group. Method: The study group included children with ADHD and the control group consisted of age- and gender-matched participants without any psychiatric disorder. In all participants, RNFL thickness, macular thickness, and macular volume were measured by using spectral domain–optical coherence tomography (SD-OCT). ADHD symptom severity was evaluated by using parent-report measures, including Conners’ Parent Rating Scale–Revised: Short Form (CPRS-R: S) and the Strengths and Difficulties Questionnaire: Parent Form (SDQ: P). Results: We compared 90 eyes of 45 children with ADHD and 90 eyes of 45 controls. ADHD group had significantly lower RNFL thickness only in nasal quadrant than the controls. The remaining RNFL quadrants, macular thickness, and volume were not significantly different between groups. There was a reverse correlation between RNFL thickness and ADHD symptom severity. Conclusion: This is the first study examining the RNFL thickness in ADHD. Our findings showed that nasal RNFL thickness was lower, indicating reduced unmyelinated axons in the retina of children with ADHD. The results of this study support the evidence that ADHD involves a lag in cortical maturation and this is measurable in the retina.

Measuring the Photopic Negative Response: Viability of Skin Electrodes and Variability Across Disease Severities in Glaucoma.

PurposeThe purpose of this study was to determine the feasibility of measuring the photopic negative response (PhNR) of the full-field electroretinogram (ERG) using skin electrodes compared to conjunctival electrodes and its test–retest variability over a range of disease severities in open-angle glaucoma.MethodsRecordings were performed twice (100 sweeps each) within the same session in 43 eyes of 23 participants with glaucoma to determine its intrinsic variability. The ratio between the PhNR and B-wave amplitude (PhNR/B ratio) was determined for each trace and computed across 5 to 100 sweeps of each recording. Spectral-domain optical coherence tomography was used to measure the average peripapillary retinal nerve fiber layer (RNFL) thickness.ResultsThe PhNR/B ratio and its magnitude of variability were not significantly different between skin and conjunctival electrodes (P ≤ 0.197), and the degree of variability decreased substantially with increasing number of sweeps. For skin electrodes, the intraclass correlation coefficient was 0.89 and 0.91 for right and left eyes, respectively. The variability of the PhNR/B ratio decreased with lower RNFL thickness values and larger B-wave amplitudes (P ≤ 0.002).ConclusionsSkin electrodes are a viable alternative to conjunctival electrodes when measuring the PhNR in open angle glaucoma, and increasing the number of sweeps substantially reduced its intrinsic variability; the extent of variability was also lower with worsening disease severity.Translational RelevanceThe feasibility of performing ERG recordings widely across a range of disease severities in glaucoma can be achieved through using skin electrodes and increasing the number of sweeps performed to improve measurement repeatability.

Functional–structural correlations in the afferent visual pathway in pediatric demyelination

We evaluated the relationship of optical coherence tomography (OCT)-measured ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL) thickness to other functional measures of afferent visual pathway competence including high-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA), visual field sensitivity, and color vision perception in a pediatric population with demyelinating disorders. This was a cross-sectional evaluation of 37 children, aged 8-18 years, with pediatric demyelinating disorders (n = 74 eyes), and 18 healthy controls (n = 36 eyes), who were recruited from the University of Toronto, Hospital for Sick Children and the University of Calgary, Alberta Children's Hospital, Canada. A standardized visual battery, including spectral-domain OCT, visual fields, LCVA, and HCVA, was performed in all subjects. Mean RNFL thickness was 26 µm (25.6%) lower in patients with demyelination (76.2 μm [3.7]) compared to controls (102.4 μm [2.1]) (p < 0.0001). Mean GCL thickness was 20% lower in patients as compared to controls (p < 0.0001). Mean GCL and RNFL thickness were strongly correlated (r = 0.89; p < 0.0001), yet in contrast to RNFL thickness, no differences in GCL thickness were noted between optic neuritis (ON) eyes and non-ON eyes of patients. HCVA and LCVA and visual field mean deviation scores decreased linearly with lower RNFL thickness. GCL thickness was decreased in patients regardless of history of ON. The retina may be a site of primary neuronal injury in pediatric demyelination.

Correlation of Retinal Nerve Fiber Layer Thickness and Visual Fields in Glaucoma: A Broken Stick Model

To determine the retinal nerve fiber layer (RNFL) thickness at which visual field (VF) damage becomes detectable and associated with structural loss. Retrospective cross-sectional study. Eighty-seven healthy and 108 glaucoma subjects (1 eye per subject) were recruited from an academic institution. All patients had VF examinations (Swedish Interactive Threshold Algorithm 24-2 test ofthe Humphrey Visual Field Analyzer 750i) and spectral-domain optical coherence tomography RNFL scans. Comparison of RNFL thickness values with VF threshold values showed a plateau of VF threshold values at high RNFL thickness values and then a sharp decrease at lower RNFL thickness values. A broken stick statistical analysis was used to estimate the tipping point at which RNFL thickness values are associated with VF defects. The slope for the association between structure and function was computed for data above and below the tipping point. The mean RNFL thickness value that was associated with initial VF loss was 89μm. The superior RNFL thickness value that was associated with initial corresponding inferior VF loss was 100μm. The inferior RNFL thickness value that was associated with initial corresponding superior VF loss was 73μm. The differences between all the slopes above and below the aforementioned tipping points were statistically significant (P< .001). In open-angle glaucoma, substantial RNFL thinning or structural loss appears to be necessary before functional visual field defects become detectable.

Comparing acromegalic patients to healthy controls with respect to intraocular pressure, central corneal thickness, and optic disc topography findings

Aims:The aim was to compare the intraocular pressure (IOP), central corneal thickness (CCT), and optic disc topography findings of biochemically controlled acromegalic patients and the control group and to evaluate the effect of the duration of acromegaly and serum growth hormone and insulin-like growth factor-1 (IGF-1) levels on these ocular parameters.Materials and Methods:IOP measurement with Goldmann applanation tonometry, CCT measurement with ultrasonic pachymetry, and topographic analysis with Heidelberg retinal tomograph III were performed on 35 biochemically controlled acromegalic patients and 36 age- and gender-matched controls.Results:Mean IOP and CCT were 14.7 ± 2.9 mmHg and 559.5 ± 44.9 μm in the acromegaly patients and 13.0 ± 1.6 mmHg and 547.1 ± 26.7 μm in controls (P = 0.006 and P = 0.15, respectively). A significant moderate correlation was found between the duration of acromegaly and CCT (r = 0.391) and IOP (r = 0.367). Mean retinal nerve fiber layer (RNFL) thickness was significantly lower in the acromegalic patients (0.25 ± 0.05 mm) as compared to controls (0.31 ± 0.09 mm) (P = 0.01). A significant moderate correlation was detected between IGF-1 level and disc area (r = 0.362), cup area (r = 0.389) and cup volume (r = 0.491).Conclusion:Biochemically controlled acromegalic patients showed significantly higher CCT and IOP levels and lower RNFL thickness compared to healthy controls and the duration of disease was correlated with CCT and IOP levels.

Influence of Cataract on Time Domain and Spectral Domain Optical Coherence Tomography Retinal Nerve Fiber Layer Measurements

To assess and compare the influence of cataract on measurements of retinal nerve fiber layer (RNFL) thickness by time domain (TD) optical coherence tomography (OCT) and spectral domain (SD) OCT. Patients who underwent uncomplicated cataract surgery were consecutively enrolled in this study. The peripapillary RNFL thickness was measured before and 8 weeks after cataract surgery using TD-OCT and SD-OCT during the same visit. Changes in the RNFL thickness measurement and signal strength (SS) after cataract surgery were evaluated. A total of 54 patients (54 eyes) were included. After excluding 19 eyes owing to poor imaging or low SS (<5), scans of 35 eyes were included in the final analysis. A significant difference was identified between the preoperative and postoperative SS values using SD-OCT, but not TD-OCT (P=0.002 and 0.789, respectively). The changes in RNFL thickness after cataract surgery were more prominent and frequent for SD-OCT than TD-OCT. There was a significant correlation between change in preoperative RNFL thickness and SS changes for both TD-OCT (r=0.410, P<0.001) and SD-OCT (r=0.246, P=0.002). The presence of cataract significantly affects RNFL thickness measurements by SD-OCT and TD-OCT. SD-OCT, which demonstrated more consistent change of RNFL measurements after cataract extraction, is not necessarily associated with lower RNFL thickness measurement performance in cataract cases, as more participants with cataract were excluded because of poor image quality or low SS, which was more associated with TD-OCT than SD-OCT.

Influence of tobacco during pregnancy in the optic nerve development

Abstract Purpose Evaluate the influence of intrauterine exposure to tobacco in the development of visual function and the retinal nerve fiber layer (RNFL) in school‐age children. Methods Retrospective cohort study with children from 5 to 14 years old. The studied subjects were divided into two groups according to the antecedent of exposure to tobacco during pregnancy: children of cigarette smoking mothers during pregnancy (exposed) and children of non‐smoking mothers (not exposed). In both groups were assessed visual acuity (VA), Ishihara test and RNFL average thickness obtained by optical coherence tomography (OCT). The mean and standard deviation of the variables were calculated, and U Mann‐Whitney test was performed for comparison of data. Results 48 children were studied, 25 boys and 23 girls. The exposed group was composed of 8 children and 40 were in the non‐exposed group. The evaluation of the visual function (VA and Ishihara test), showed no statistically significant differences between groups. However, the RNFL average thickness was of 94.64 and 103.88 microm for the exposed and non‐exposed group, respectively; these data showed statistically significant differences between both values. Conclusion The intrauterine exposure to tobacco is associated with a poor development of the optic nerve. This fact determines a lower RNFL thickness measured by OCT.

Scanning Laser Polarimetry with Variable Corneal Compensation in the Area of Apparently Normal Hemifield in Eyes with Normal-Tension Glaucoma

To evaluate the retinal nerve fiber layer (RNFL) in the retinal segments without visual field loss in eyes with normal-tension glaucoma (NTG) that have localized visual field defects. Prospective interventional case series. Fifty-six Asian glaucoma patients with localized visual field defects confined to 1 hemifield and 43 normal control participants. A complete ophthalmic examination, the 24-2 full-threshold test on the Humphrey Field Analyzer (HFA; Carl Zeiss Meditec, Dublin, CA), and scanning laser polarimetry with variable corneal compensation (SLP-VCC; GDx-VCC, Carl Zeiss Meditec) were performed in each participant. We compared RNFL thickness parameters on SLP-VCC printouts and severity scores based on the SLP-VCC deviation map algorithm in retinal segments with corresponding visual field defects with those in segments without visual field defects and with those in matched segments of age-matched normal controls. Linear regression analyses were performed between the RNFL thickness parameters and the severity scores in both segments with corresponding visual field defects and those without visual field defects and HFA indices (mean deviation, corrected pattern standard deviation) in these NTG eyes. Seven of 56 eyes with NTG showed abnormal RNFL thickness parameters (P<0.05) in the quadrants without visual field defects, whereas no eye showed abnormal RNFL thickness parameters (P<0.05) in the matched quadrant of the control group. The mean RNFL thickness parameter in the quadrants without visual field defects in the NTG eyes was 62.41+/-7.71, which was significantly lower than in the matched quadrants of the control group (74.57+/-9.21; P<0.001) but was significantly higher than in the quadrants with corresponding visual field defects in NTG eyes (48.01+/-9.45; P<0.001). The severity score in the matched quadrants of control eyes was 0.53+/-3.20, whereas the severity score of quadrants without visual field defects of the NTG eyes was 13.52+/-35.40 (P<0.001). Perimetrically normal hemifields of NTG eyes showed significantly lower RNFL thickness parameters than the corresponding retinal regions of healthy eyes, as measured by SLP-VCC. Scanning laser polarimetry with variable corneal compensation may have potential as an ancillary diagnostic tool in the evaluation of the corresponding RNFL without visual field defects in NTG eyes with localized visual field defects.

Diurnal variation of intraocular pressure and its correlation with retinal nerve fiber analysis in Turkish patients with exfoliation syndrome

The purpose was to evaluate the diurnal variation (DV) of intraocular pressure (IOP) in patients with exfoliation syndrome (XS), to measure retinal nerve fiber layer (RNFL) thickness by using scanning laser polarimetry, and to compare these measurements with those of normal subjects. Forty-five subjects with XS and 40 healthy, age/sex matched subjects were recruited into the study. A detailed ophthalmologic examination was performed. IOP measurements were obtained at 08:00 am, 12:00 pm, 03:00 pm, and 06:00 pm. The XS group was further divided into DV > or = 5 mmHg and DV < 5 mmHg groups and also according to the existence of IOP fluctuation. The IOP measurements and RNFL thickness measurements were compared between the groups. The mean IOP value was found to be highest in the morning both in the XS and control groups. IOP showed a gradual decrease from 8.00 am to 6.00 pm in the control group, whereas a second peak at 03:00 pm was observed in the XS group. There was a fluctuation in 53.3% of the XS group, while none of the healthy subjects showed fluctuation. Superior and inferior ratios were statistically lower in XS patients than those in control subjects (p<0.05). Moreover, in patients with XS showing a DV > or = 5 mmHg and/or a fluctuation, the superior ratio, inferior ratio, the number, superior average and superior integral were significantly different (all p values <0.05) from those of control subjects. As the XS patients with high diurnal IOP variation and fluctuating pattern of IOP had lower RNFL thickness measurements, it is crucial to follow up these patients by performing scanning laser polarimetry in order to discover any possible glaucomatous damage at an earlier stage than with the use of conventional visual field analysis.