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Purpose: This study aimed at establishing the normative data for the thickness of macular layers on Spectralis Spectral-domain optical coherence tomography (SD-OCT) in healthy Indian eyes and testing the effects of age, gender, central corneal thickness (CCT), and intraocular pressure (IOP) on such values.Methods: This cross-sectional study was done on 308 eyes of 159 healthy subjects. OCT scans were obtained using the posterior pole asymmetry scan protocol. From the thickness map, data were grouped into nine Early Treatment Diabetic Retinopathy Study (ETDRS) macular sectors. Correlation between retinal thickness and age/IOP/CCT was done using Pearson correlation. Correcting for age as a covariate, multivariate regression analysis was done to know which retinal layers showed significant differences in thickness between males and females.Results: The mean age was 46.06 ± 13.06 years (range: 20-75 years). Significant central subfield (CSF) thickening with age was noted in retinal nerve fiber layer (RNFL), inner nuclear layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), and outer nuclear layer (ONL) (P < 0.04). The average thickness of the outer ring reduced with age in the ganglion cell layer (GCL)/IPL/INL (P = 0.001). Women had thinner inner and outer retinal thickness than men in all ETDRS rings (P < 0.001). There was no interocular asymmetry (P > 0.05) and no correlation between IOP/CCT and retinal layer thickness.Conclusion: In CSF, age-related thickening was noted in RNFL, IPL, INL, OPL, and ONL. The average inner ring thickness decreased with age in GCL and IPL and increased in the RPE layer. The average outer ring thickness decreased with age in GCL, IPL, and INL layers and increased in OPL. The average IR and OR thickness was significantly less in women compared to men in all sub-fields. There was no correlation between IOP/CCT and retinal layer thickness. [ABSTRACT FROM AUTHOR]

Background: We evaluated the performance of an automated algorithm available on a clinical OCT (Canon-HS100) for macular volumetric measurements of eight individual retinal layers. Methods and Analysis: Two consecutive three-dimensional scans were acquired on 29 subjects with healthy retinas. Thickness measurements were obtained from eight individual retinal layers in nine macular sectors based on Early Treatment Diabetic Retinopathy Study (ETDRS) protocol. The repeatability was evaluated using the within-subject standard deviation from which the repeatability limits (Rlimit) and coefficient of variation (CoV) were calculated. Results: The repeatability metrics varied among different layers and sectors. The variation among the sectors was larger in two of the outer layers (plexiform and nuclear layer) and the retinal nerve fiber layer. For the other five layers, the repeatability limit was less than 5µm and CoV was less than 7.5% in all nine ETDRS sectors. Conclusions: The repeatability of the OCT-HS100 to measure eight individual retinal layers is good in general. Nevertheless, the repeatability is not homogeneous among different layers and sectors. This needs to be taken into account while designing clinical measurement protocols. [ABSTRACT FROM AUTHOR]

The effects of optic neuritis in patients with multiple sclerosis (MS) on the thickness of individual macular layers was analysed by means of optical coherence tomography (OCT). Data of 15 patients (mean age 37.2 years, range 16--50) with multiple sclerosis and 15 normal subjects (mean age 37.7 years, range 17--67) were analysed. Twelve patients had suffered from an attack of acute unilateral optic neuritis in one or both eyes. OCT scans of the circumpapillary retinal nerve fibre layer (RNFL) and of the macula were obtained by means of fast scan protocols. The characteristic sequence of five intensity maxima and four intensity minima was attributed to the mean location of the individual macular layers. The eyes affected by optic neuritis showed significant (p < 0.05) reductions of RNFL thickness by 30.5%, of macular volume (MV) by 12.8%, and of inner macular layers. The mean reduction was 16.2% (macular nerve fibre layer), 31.1% (ganglion cell layer [GCL]), and 25.9% (inner plexiform layer [IPL]), respectively. However, significant reductions of RNFL thickness (by 9.0%), MV (by 5.0%), CGL (by 10.3%), and IPL (by 10.8%) were found also in the unaffected eyes of MS patients. Thus, the quantitative analysis of the axial reflectivity profiles from exported OCT images offers an appropriate method for the characterisation of the location of macular changes after optic neuritis. The shrinking of inner macular layers is a more sensitive parameter of postneuritic optic atrophies than the reduction of MV. [ABSTRACT FROM AUTHOR]