Significant Retinal Nerve Fiber Layer Thinning Research Articles

Prospective Study on Retinal Nerve Fibre Layer Thickness Changes in Isolated Unilateral Retrobulbar Optic Neuritis

Purpose. To investigate the retinal nerve fibre layer (RNFL) thickness after unilateral acute optic neuritis using optical coherence tomography (OCT). Patients and Methods. This prospective cohort study recruited consecutive patients with a first episode of isolated, unilateral acute optic neuritis. RNFL thickness and visual acuity (VA) of the attack and normal fellow eye were measured at presentation and 3 months in both the treatment and nontreatment groups. Results. 11 subjects received systemic steroids and 9 were treated conservatively. The baseline RNFL thickness was similar in the attack and fellow eye (P ≥ 0.4). At 3 months, the attack eye had a thinner temporal (P = 0.02) and average (P = 0.05) RNFL compared to the fellow eye. At 3 months, the attack eye had significant RNFL thinning in the 4 quadrants and average thickness (P ≤ 0.0002) compared to baseline. The RNFL thickness between the treatment and nontreatment groups was similar at baseline and 3 months (P ≥ 0.1). Treatment offered better VA at 3 months (0.1 ± 0.2 versus 0.3 ± 0.2 LogMAR, P = 0.04). Conclusion. Generalized RNFL thinning occurred at 3 months after a first episode of acute optic neuritis most significantly in the temporal quadrant and average thickness. Visual improvement with treatment was independent of RNFL thickness.

Scanning Laser Polarimetry Quantification of Retinal Nerve Fiber Layer Thinning Following Optic Neuritis

Several studies with optical coherence tomography (OCT) have demonstrated thinning of the retinal nerve fiber layer (RNFL) in patients with optic neuritis and multiple sclerosis. Similar studies have not been performed with scanning laser polarimetry (SLP), which relies on different physical phenomena. This study was designed to use SLP to measure axonal loss following a single episode of optic neuritis and to determine if there is a relationship between the degree of axonal loss and the degree of residual visual dysfunction. Twenty-five patients with a single episode of optic neuritis and 15 control subjects were studied with SLP using the GDxVCC device to determine RNFL thickness in relation to visual acuity, visual fields, color vision, visual evoked potentials (VEPs), and previously published OCT data. SLP detected significant RNFL thinning in affected eyes compared to clinically unaffected fellow eyes in patients and in control eyes (P < 0.001). Reduced RNFL thickness was associated with significantly worse logMAR visual acuity, visual field mean deviation, and color vision. RNFL thinning correlated with reduced whole visual field and central visual field measures and VEP amplitudes. Superior and inferior quadrant RNFL thinning was related to corresponding regional visual field loss. There was a scaling factor between SLP and OCT RNFL measurements but only modest agreement. SLP detected functionally relevant axonal loss in eyes affected by optic neuritis. There was a scaling factor between RNFL measurements obtained with SLP and OCT but only modest agreement. Care should therefore be taken when comparing RNFL data from studies using these different devices.

Structural and Functional Assessment in HIV-Infected Patients Using Optical Coherence Tomography and Frequency-Doubling Technology Perimetry

To assess retinal nerve fiber layer (RNFL) and macular thickness using optical coherence tomography (OCT) on HIV-infected patients without ocular manifestations and to correlate these findings with frequency-doubling technology perimetry (FDT). Cross-sectional study. setting: Single center. study population: Seventy-three patients (146 eyes) with clinically normal examination classified in 3 groups: group A, HIV-infected patients with CD4 count <100 cells/mm(3) for at least 6 months; group B, HIV-infected patients with CD4 count >100 cells/mm(3) since diagnosis; and group C, HIV-negative control subjects. observation procedures: Fast RNFL and fast macula scan strategies on Stratus OCT and Humphrey Matrix 24-2 full-threshold program. main outcome measures: OCT RNFL and macular thicknesses and FDT indices (mean deviation [MD], pattern standard deviation [PSD], and glaucoma hemifield test [GHT]). Group A had a significantly thinner average RNFL, temporal outer macula, and inferior outer macula thicknesses when compared to groups B and C (P < .05). Statistically significant differences were observed in the FDT MD between groups A and C (P = .034) and in PSD in group A compared to groups B and C (P = .011). Eyes of HIV patients with GHT and PSD results outside normal confidence limits had thinner average RNFL thickness measures than eyes with results within normal limits in the same group of patients (P < .05). HIV-infected patients with low CD4 count have a significant RNFL and macular thinning. Functional loss detected by FDT is related to RNFL thinning in HIV-infected patients.

The effect of ageing on retinal nerve fibre layer thickness: an evaluation by scanning laser polarimetry with variable corneal compensation

To evaluate whether a significant age-related thinning of the retinal nerve fibre layer (RNFL) is measurable by means of scanning laser polarimetry with variable corneal compensation (GDx-VCC) in a sample of healthy eyes. A sample of 324 eyes of 324 healthy subjects (mean age 56 +/- 14 years, range 21-85 years) underwent a complete ophthalmic evaluation, standard automated perimetry and RNFL scan with the GDx-VCC. Temporal-superior-nasal-inferior-temporal (TSNIT), superior and inferior average (SA and IA) values provided on the printout were collected and their mean value averaged from all eyes and also after separating the eyes by gender and by age decades. The values of the three parameters were plotted against age and linear regression was calculated. Ageing is associated with a significant RNFL thinning (0.08 micro, 0.16 micro and 0.12 micro per year for TSNIT, SA and IA, respectively; p < 0.001). Analysis showed a similar association with age decade (p < 0.001 on anova). For the TSNIT average, a 9.5% thinning from baseline values was estimated for a 65-year lifespan. Corresponding values for SA and IA were 16.2% and 11.7%, respectively. Analysis by GDx-VCC confirmed previous reports about significant age-related RNFL thinning. However, a lower rate per year was found, probably because GDx-VCC measurements are much more reliable than those obtained with the previous generation of polarimeters.

Optic nerve atrophy and retinal nerve fibre layer thinning following optic neuritis: Evidence that axonal loss is a substrate of MRI-detected atrophy

Magnetic resonance imaging (MRI) measures of brain atrophy are often considered to be a marker of axonal loss in multiple sclerosis (MS) but evidence is limited. Optic neuritis is a common manifestation of MS and results in optic nerve atrophy. Retinal nerve fibre layer (RNFL) imaging is a non-invasive way of detecting axonal loss following optic neuritis. We hypothesise that if the optic nerve atrophy that develops following optic neuritis is contributed to by axonal loss, it will correlate with thinning of the RNFL. Twenty-five patients were studied at least 1 year after a single unilateral attack of optic neuritis without recurrence, with a selection bias towards incomplete recovery. They had MR quantification of optic nerve cross-sectional area and optic nerve lesion length, as well as optical coherence tomography (OCT) measurement of mean RNFL thickness and macular volume, quantitative visual testing, and visual evoked potentials (VEPs). Fifteen controls were also studied. Significant optic nerve atrophy (mean decrease 30% versus controls), RNFL thinning (mean decrease 33% versus controls), and macular volume loss occurred in patients' affected eyes when compared with patients' unaffected eyes and healthy controls. The optic nerve atrophy was correlated with the RNFL thinning, macular volume loss, visual acuity, visual field mean deviation, and whole field VEP amplitude but not latency. These findings suggest that axonal loss contributes to optic nerve atrophy following a single attack of optic neuritis. By inference, axonal loss due to other post-inflammatory brain lesions is likely to contribute to the global MRI measure of brain atrophy in multiple sclerosis.