Retinal Nerve Fiber Layer Measurements Research Articles

Don't get off the track

A 43-year-old man noted decreased vision after head trauma, with normal neuroimaging acutely. He had a left homonymous hemianopia, confirmed with hemifield visual evoked potentials, from trauma to the right optic tract. Four months after trauma, a magnetic resonance imaging of the brain showed atrophy of the right optic tract, and funduscopy revealed optic disk pallor with decreased retinal nerve fiber layer measures consistent with an optic tract syndrome.

Optical coherence tomography as a marker of neurodegeneration in patients with Wilson\u2019s disease

Wilson’s disease (WD) is an inherited autosomal recessive disorder that leads to pathological copper accumulation in different organs. Optical coherence tomography (OCT) is proposed as a marker of neurodegeneration in many neurological diseases. Thinning of the total retinal nerve fiber layer (RNFL) and macular thickness (Mth) examined by OCT was detected in patients with WD, especially those with brain magnetic resonance imaging changes. The aim of this study was to evaluate the relationship between OCT parameters and the progression of neurological signs measured by the Unified Wilson’s Disease Rating Scale (UWDRS) in patients with WD. Consecutive patients with WD admitted to the Department of Neurology underwent OCT to assess the thickness of the macula and total RNFL. Patients also had neurologic assessments according to the UWDRS part III. Patients were divided into two groups based on the presence (UWDRS+) and absence (UWDRS−) of neurological symptoms. Fifty-eight patients (34 females, 24 males) were enrolled. Mean duration of treatment was 9 years (standard deviation [SD], ±10.8). The mean UWDRS score at the time of study was 8.4 (range 1–52; SD ±13.9) points. Total RNFL as well as macula thickness were significantly decreased in the UWDRS+ group versus the UWDRS− group. A significant negative correlation was found between OCT parameters (RNFL and Mth measurements) and neurological impairment according the UWDRS scale. This study confirms that OCT may be a useful tool for measuring the degree of neurodegeneration in patients with WD, and may play role in monitoring disease progression.

Predicting the Magnitude of Functional and Structural Damage in Glaucoma From Monocular Pupillary Light Responses Using Automated Pupillography.

To predict the magnitude of functional damage [mean deviation (MD) on visual field examination] and structural damage [retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness on spectral domain optical coherence tomography] in glaucoma from monocular pupillary light response measurements using automated pupillography. In total, 59 subjects (118 eyes) with either a confirmed or suspected diagnosis of glaucoma underwent automated pupillography, along with visual fields and spectral domain optical coherence tomography examinations. Association between pupillary light response measurements of each eye [amplitude of constriction, latency of onset of constriction (Loc), latency of maximal constriction (Lmaxc), velocity of constriction and velocity of redilation] and corresponding MD, average RNFL, and average GCC measurements were evaluated using univariate and multivariate regression analysis after accounting for the multicollinearity. Goodness of fit of the multivariate models was evaluated using coefficient of determination (R). Multivariate regression models that contained Loc and Lmaxc showed the best association with MD (R of 0.30), average RNFL thickness (R=0.18) and average GCC thickness (R=0.26). The formula that best predicts the MD could be described as: MD=-14.06-0.15×Loc+0.06×Lmaxc. The formula that best predicts the average RNFL thickness could be described as: Average RNFL thickness=67.18-0.22×Loc+0.09×Lmaxc. Glaucomatous damage as estimated by MD, RNFL, and GCC thickness measurements were best predicted by the latency parameters (Loc and Lmaxc) of pupillography. Worsening of glaucomatous damage resulted in a delayed onset of pupillary constriction and a decreased Lmaxc.

Variations in retinal nerve fiber layer measurements on optical coherence tomography after implantation of trifocal intraocular lens

To establish the changes produced after implantation of a trifocal intraocular lens (IOL) on retinal nerve fiber layer measurements performed with Fourier-domain optical coherence tomography (OCT). This prospective study included 100 eyes of 50 patients with bilateral cataract in surgical range, no other associated ocular involvement, refractive errors between +5 and -5 spherical diopters, and less than 1.5 D of corneal astigmatism. The eyes were operated by phacoemulsification with implantation of 2 different trifocal IOLs (FineVision and AT LISA tri 839MP) in randomized equal groups. Cirrus OCT and Spectralis OCT were performed before surgery and 3 months later. Both analyzed the thickness of the nerve fiber layer and thickness divided by quadrants (6 in case of Spectralis and 4 in case of Cirrus HD). The mean age of patients was 67.5 ± 5.8 years. The global nerve fiber layer thickness measured with Spectralis OCT was 96.77 μm before surgery and 99.55 μm after. With Cirrus OCT, the global thickness was 85.29 μm before surgery and 89.77 μm after. Statistically significant differences in global thickness measurements between preimplantation and postimplantation of the IOL were found with both OCT in the 2 groups. Statistically significant differences were also found in temporal and superior quadrants. The implantation of a diffractive trifocal IOL alters the results of the optic nerve fiber layer on Fourier-domain OCT in these patients, which should be taken into account in the posterior study of these patients.

A comparison of the diagnostic ability of vessel density and structural measurements of optical coherence tomography in primary open angle glaucoma

PurposeTo compare the diagnostic abilities of vessel density measurements of the optic nerve head (ONH), peripapillary and macular regions on optical coherence tomography (OCT) angiography in eyes with primary open angle glaucoma (POAG) with that of the ONH rim area, peripapillary retinal nerve fiber layer (RNFL) thickness and the macular ganglion cell complex (GCC) thickness measurements.MethodsIn a cross sectional study, 78 eyes of 50 control subjects and 117 eyes of 67 POAG patients underwent vessel density and structural measurements with spectral domain OCT. POAG was diagnosed based on the masked evaluation of optic disc stereo photographs. Area under receiver operating characteristic curves (AUC) and sensitivities at fixed specificities of vessel densities in ONH, peripapillary and macular regions were compared with rim area, RNFL and GCC thickness.ResultsThe AUC (sensitivity at 95% specificity) of average vessel densities within the ONH, peripapillary and macular region were 0.77 (31%), 0.85 (56%) and 0.70 (18%) respectively. The same of ONH rim area, average RNFL and GCC thickness were 0.94 (83%), 0.95 (72%) and 0.93 (62%) respectively. AUCs of vessel densities were significantly lower (p<0.05) than that of the corresponding structural measurements. Pre-treatment IOP (coefficient: 0.08) affected (p<0.05) the AUC of ONH vessel density but not of any other vessel density or structural measurements.ConclusionsDiagnostic abilities of ONH, peripapillary and the macular vessel densities in POAG were significantly lower than ONH rim area, peripapillary RNFL and macular GCC measurements respectively. At fixed levels of glaucoma severity, the diagnostic ability of the ONH vessel density was significantly greater in eyes with higher pre-treatment IOP.

Assessment of Retinal Nerve Fiber Layer Changes by Cirrus High-definition Optical Coherence Tomography in Myopia.

ABSTRACTIntroduction To evaluate the relationship between retinal nerve fiber layer (RNFL) thickness measured by Cirrus high-definition (HD) optical coherence tomography (OCT) and the axial length and refractive error of the eye.Materials and methods A total of 100 eyes of 100 healthy subjects (age 20-34 years with M/F ratio of 57/43), comprising 50 eyes with emmetropia [spherical equivalent (SE) 0 D], 25 eyes with moderate myopia (SE between -4 D and -8 D), and 25 eyes with high myopia (SE between -8 D and -12 D) were analyzed in this cross-sectional study. Average and mean clock hour RNFL thicknesses were measured by cirrus HD-OCT and compared between the three groups. Associations between RNFL measurements and axial length and SE were evaluated by linear regression analysis.Results The average RNFL measurements were significantly lower in high myopia (78.68 +/- 5.67) and moderate myopia (83.76 +/- 3.44) group compared with emmetropia group (91.26 +/- 2.99), also in the superior and inferior mean clock hours. Significant correlations were evident between RNFL measurements and the SE and axial length. The average RNFL thickness decreased with increasing axial length (r = -0.8115) and negative refractive power (r = 0.8397). Myopia also affected the RNFL thickness distribution. As the axial length increased and the SE decreased, the thickness of the superior, inferior, and nasal peripapillary RNFL decreased.Conclusion The axial length/refractive error of the eye affected the average RNFL thickness and the RNFL thickness distribution. Analysis of RNFL thickness in the evaluation of glaucoma should always be interpreted with reference to the refractive status. When interpreting the RNFL thickness of highly myopic patients by OCT, careful attention must be given to the inherently thinner RNFL to avoid a false diagnosis of glaucoma.How to cite this article Singh D, Mishra SK, Agarwal E, Sharma R, Bhartiya S, Dada T. Assessment of Retinal Nerve Fiber Layer Changes by Cirrus High-definition Optical Coherence Tomography in Myopia. J Curr Glaucoma Pract 2017;11(2):52-57.

Anxiety During Pregnancy and Postpartum: Course, Predictors and Comorbidity with Postpartum Depression.

Previous findings on peripartum anxiety are inconsistent in respect to the prevalence and course of peripartum anxiety with comorbidity of depression. Our aim was threefold: (1) to examine the course of elevated anxiety during pregnancy, immediately after childbirth, and six weeks postpartum; (2) to establish comorbidity of postpartum anxiety and postpartum depression (PPD); and (3) to examine predictors of anxiety 6 weeks postpartum. A sample of women (N=272) who were below the cut-off score for clinical depression during pregnancy were assessed in the third trimester of pregnancy, then 2 days and 6 weeks postpartum. Questionnaires on anxiety, pregnancy specific distress, stress, coping styles, social support, and depression were administered at each assessment. Obstetric data were collected from the participants' medical records. The estimated rate of high anxiety was 35% during pregnancy, 17% immediately after childbirth, and 20% six weeks postpartum, showing a decrease in anxiety levels after childbirth. Comorbidity of anxiety and PPD was 75%. Trait anxiety and early postpartum state anxiety are significant predictors of postpartum anxiety. Anxiety is a common peripartum psychological disturbance. Anxiety symptoms overlap with PPD, but not com-pletely, indicating that screening for postpartum mental difficulties should include both depression and anxiety.

Correlation between Visual Field Index and Other Functional and Structural Measures in Glaucoma Patients and Suspects.

Purpose:To evaluate the correlation between visual field index (VFI) and both structural and functional measures of the optic disc in primary open angle glaucoma patients and suspects.Methods:In this retrospective study, 162 glaucoma patients and suspects underwent standard automated perimetry (SAP), retinography, and retinal nerve fiber layer (RNFL) measurement. The optic disc was stratified according to the vertical cup/disc ratio (C/D) and sorted by the disc damage likelihood scale (DDLS). RNFL was measured with the optical coherence tomography. The VFI perimetry was correlated with the mean deviation (MD) and pattern standard deviation (PSD) obtained by SAP, and structural parameters by Pearson's correlation coefficients.Results:VFI displayed strong correlation with MD (R = 0.959) and PSD (R = −0.744). The linear correlations between VFI and structural measures including C/D (R = −0.179, P = 0.012), DDLS (R = −0.214, P = 0.006), and RNFL (R = 0.416, P < 0.001) were weak but statistically significant.Conclusion:VFI showed a strong correlation with MD and PSD but demonstrated a weak correlation with structural measures. It can possibly be used as a marker for functional impairment severity in patients with glaucoma.

Diagnostic Ability of Retinal Nerve Fiber Layer Thickness Deviation Map for Localized and Diffuse Retinal Nerve Fiber Layer Defects.

Purpose. To evaluate the diagnostic ability of the retinal nerve fiber layer (RNFL) deviation map for glaucoma with localized or diffuse RNFL defects. Methods. Eyes of 139 glaucoma patients and 165 healthy subjects were enrolled. All participants were imaged with Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA, USA). A RNFL defect was defined as at least 10 contiguous red (<1% level) superpixels in RNFL deviation map. The area, location, and angular width of RNFL defects were automatically measured. We compared sensitivities, specificities, and area under the receiver operating characteristic curves (AUCs) of RNFL deviation map and circumpapillary RNFL thickness for localized and diffuse RNFL defects. Subgroup analysis was performed according to the severity of glaucoma. Results. For localized defects, the area of RNFL defects (AUC, 0.991; sensitivity, 97%; specificity, 90%) in deviation map showed a higher diagnostic performance (p = 0.002) than the best circumpapillary RNFL parameter (inferior RNFL thickness; AUC, 0.914; sensitivity, 79%; specificity, 92%). For diffuse defects, there was no significant difference between the RNFL deviation map and circumpapillary RNFL parameters. In mild glaucoma with localized defect, RNFL deviation map showed a better diagnostic performance than circumpapillary RNFL measurement. Conclusions. RNFL deviation map is a useful tool for evaluating glaucoma regardless of localized or diffuse defect type and has advantages over circumpapillary RNFL measurement for detecting localized RNFL defects.

Effect of Refractive Correction Error on Retinal Nerve Fiber Layer Thickness: A Spectralis Optical Coherence Tomography Study.

BackgroundIdentifying and assessing retinal nerve fiber layer defects are important for diagnosing and managing glaucoma. We aimed to investigate the effect of refractive correction error on retinal nerve fiber layer (RNFL) thickness measured with Spectralis spectral-domain optical coherence tomography (SD-OCT).Material/MethodsWe included 68 participants: 32 healthy (normal) and 36 glaucoma patients. RNFL thickness was measured using Spectralis SD-OCT circular scan. Measurements were made with a refractive correction of the spherical equivalent (SE), the SE+2.00D and the SE–2.00D.ResultsAverage RNFL thickness was significantly higher in the normal group (105.88±10.47 μm) than in the glaucoma group (67.67±17.27 μm, P<0.001). In the normal group, +2.00D of refractive correction error significantly affected measurements of average (P<0.001) and inferior quadrant (P=0.037) RNFL thickness. In the glaucoma group, +2.00D of refractive correction error significantly increased average (P<0.001) and individual quadrant (superior: P=0.016; temporal: P=0.004; inferior: P=0.008; nasal: P=0.003) RNFL measurements compared with those made with the proper refractive correction. However, −2.00D of refractive correction error did not significantly affect RNFL thickness measurements in either group.ConclusionsPositive defocus error significantly affects RNFL thickness measurements made by the Spectralis SD-OCT. Negative defocus error did not affect RNFL measurement examined. Careful correction of refractive error is necessary to obtain accurate baseline and follow-up RNFL thickness measurements in healthy and glaucomatous eyes.

Diagnostic ability of peripapillary vessel density measurements of optical coherence tomography angiography in primary open-angle and angle-closure glaucoma

AimsTo evaluate the diagnostic ability of peripapillary vessel density measurements on optical coherence tomography angiography (OCTA) in primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG), and to compare these...

Investigation of the effects of systemic isotretinoin treatment on retinal nerve fiber layer and macula

Purpose: To investigate the effects of systemic isotretinoin therapy on retina by measuring retinal nerve fiber layer (RNFL) and macular thicknesses.Method: This prospective, cross-sectional study was conducted in patients prescribed systemic isotretinoin therapy. Seventy-two eyes of 36 patients were included in the study. The patients were followed during three months. Detailed ophthalmologic examination including anterior and posterior segment examination, best corrected visual acuity and intraocular pressure measurement, RNFL and macular thicknesses measurement by Spectral Domain Cirrus Optical Coherence Tomography Model 400 (Carl Zeiss Meditech, Jena, Germany) were performed at baseline, first, second and third months after the beginning of systemic isotretinoin therapy in ophthalmology clinic.Result: Thirty (83.3%) of the 36 patients were women and six (16.7%) of them were men. Mean age was 21.17 years. Mean RNFL thickness in the temporal quadrant at first, second, third months after beginning of treatment were found as significantly lower compared to baseline (p = .001). Mean macular thicknesses in superior outer, nasal outer and temporal outer quadrants at second and third months after beginning of treatment were found to be significantly lower compared to baseline and first month after beginning of treatment (p ≤ .001, .002 and .001, respectively). Macular thicknesses in superior inner quadrant at first, second and third months were found to be significantly lower than baseline values (p< .01). No significant difference was detected between groups in other quadrants (p> .05).Conclusion: The effect of oral isotretinoin therapy may cause regional thinning in RNFL and macula, directly visible part of central nervous system.

Discriminant Function of Optical Coherence Tomography Angiography to Determine Disease Severity in Glaucoma.

To determine the discriminant function of optical coherence tomography angiography (OCTA) by disease severity in glaucoma. In this prospective, observational cross-sectional study, all subjects underwent visual fields, retinal nerve fiber layer (RNFL) measurements, and OCTA imaging. Local fractal analysis was applied to OCTA images (radial peripapillary capillaries [RPC] layer). Vessel density en face and inside the disc and spacing between large and small vessels were quantified. Stepwise logistic regression was performed and a glaucoma severity score (range, 0-1: 0, normal; 1, severe glaucoma) was developed by using global and regional (superotemporal [ST], inferotemporal [IT], temporal, superonasal [SN], inferonasal, and nasal) vascular parameters. Glaucoma severity score was compared with visual field and RNFL indices. One hundred ninety-nine eyes (112 subjects) with glaucoma (28 eyes preperimetric; 83 early, 43 moderate, and 45 severe glaucoma) and 74 normal (54 subjects) eyes were enrolled. Preperimetric and glaucomatous eyes had significantly altered (P < 0.001) global vascular parameters as compared to normal; regionally, ST, then SN and IT sectors (in that order) showed more change in glaucomatous eyes. Vascular parameters showed better discriminant ability (area under the curve [AUC], sensitivity, and specificity of 0.70, 69.2%, and 72.9%, respectively) than structural parameters between normal and preperimetric glaucomatous eyes. Vascular parameters had comparable AUC (P > 0.05) to visual fields for perimetric glaucoma. Glaucoma severity score identified preperimetric glaucoma and early glaucoma better than did visual fields. Vascular parameters could be a useful adjunct tool to evaluate/diagnose glaucoma. Longitudinal studies are needed to determine their use in early detection and prognostication.

Retinal nerve fiber layer thickness in a healthy Turkish population measured by optical coherence tomography.

BACKGROUNDNormative optical coherence tomography (OCT) data is required for different subsets of the population as ethnic differences in retinal nerve fiber layer (RNFL) thickness have been reported. An OCT database for the normal Turkish population is not commercially available.OBJECTIVESQuantify peripapillary RNFL thickness in a Turkish population.DESIGNCross-sectional, descriptive study.SETTINGNumune Training and Research Hospital, Adana, Turkey.SUBJECTS AND METHODSRNFL measurements performed by Spectral OCT with a circular scan with 3.4 mm circle were centered around the optic disc of the right eye of each subject. Correlation of the effects of age and gender on RNFL thickness was analyzed.MAIN OUTCOME MEASURE(S)Correlation and measurements of RNFL. Retinal nerve fiber layer thickness measurements were obtained for the entire circumference of the optic nerve head.RESULTSIn 307 healthy subjects consisting of 135 (44%) males and 172 (56%) females, with a mean (SD) age of 35.1 (9.6) years (range, 20–50 years), RNFL was superior: 132.2 (16.63) μm, inferior: 139.1 (14.53) μm, nasal: 96.2 (14.23) μm, temporal: 79.8 (10.7) μm. The mean (SD) RNFL thickness for the group was 111.5 (9.3) μm. There was no significant difference between the average RNFL thicknesses of age groups nor between males and females (P=.1, P=.42), and no significant correlation with respect to age (P=.430, r=−.04). There was a statistically significant difference between the inferior quadrants of the two genders (P=.04).CONCLUSIONSRNFL thickness did not vary significantly with gender. A weak negative but statistically nonsignificant correlation between average RNFL thickness and age was found.LIMITATIONSThe participants were young adults or at early middle age so age effects on RNFL thickness may not be explained. The data does not reflect the entire Turkish population, which is not homogeneous.

The Effect of Optic Disc Center Displacement on Retinal Nerve Fiber Layer Measurement Determined by Spectral Domain Optical Coherence Tomography.

PurposeTo investigate the effect of optic disc center displacement on retinal nerve fiber layer (RNFL) measurement determined by spectral domain optical coherence tomography (SD-OCT).MethodsThe optic disc center was manipulated at 1-pixel intervals in horizontal, vertical, and diagonal directions. According to the manipulated optic disc center location, the RNFL thickness data were resampled: (1) at a 3.46-mm diameter circle; and (2) between a 2.5-mm diameter circle and 5.4-mm square. Error was calculated between the original and resampled RNFL measurements. The tolerable error threshold of the optic disc center displacement was determined by considering test-retest variability of SD-OCT. The unreliable zone was defined as an area with 10% or more variability.ResultsThe maximum tolerable error thresholds of optic disc center displacement on the RNFL thickness map were distributed from 0.042 to 0.09 mm in 8 directions. The threshold shape was vertically elongated. Clinically important unreliable zones were located: (1) at superior and inferior region in the vertical displacement; (2) at inferotemporal region in the horizontal displacement, and (3) at superotemporal or inferotemporal region in the diagonal displacement. The unreliable zone pattern and threshold limit varied according to the direction of optic disc displacement.ConclusionsOptic disc center displacement had a considerable impact on whole RNFL thickness measurements. Understanding the effect of optic disc center displacement could contribute to reliable RNFL measurements.

Interocular symmetry of the peripapillary choroidal thickness and retinal nerve fibre layer thickness in healthy adults with isometropia.

BackgroundThe aim of this study was to determine the interocular differences in the peripapillary retinal nerve fibre layer (RNFL), peripapillary choroidal thickness (PCT) and subfoveal choroidal thickness (SFCT) in healthy adults with isometropia, using enhanced depth imaging optical coherence tomography (EDI SD-OCT).MethodsOne hundred healthy Chinese adults with spherical equivalents of ≤ ±3 dioptres and interocular differences of <0.5 dioptres were prospectively enrolled in this study. They underwent RNFL and PCT measurements via EDI SD-OCT, with a 3.4 mm scan circle centred on the optic nerve head. Subfoveal choroidal thickness (SFCT) measurements were also taken with a horizontal line scan centred on the macula. Right and left eyes were compared by a paired t-test, and the interocular differences were calculated. The agreement and correlations of the RNFLs, PCTs and SFCTs between the right and left eyes were analysed.ResultsEighty-six subjects (172 eyes) were included in the final analysis, consisting of 44 (51.6 %) males and 42 (48.8 %) females; 55 (63.9 %) had emmetropia and 33 (36.1 %) had ametropia. The RNFL was statistically significantly thicker in the right eyes when compared to the left eyes in the temporal quadrant, and thinner on average in the nasal superior quadrant (p < 0.05). However, the differences in the choroidal thicknesses in all of the quadrants between the right and left eyes were not statistically significant. The tolerance limits of the average RNFL were −21.1 μm and 7.1 μm, and the mean and standard deviation of the interocular difference in the average PCT was −2.2 ± 24.2 μm. The RNFLs and PCTs in all of the locations in the right eyes were significantly correlated with those in the left eyes. However, no significant associations between the age, sex, interocular asymmetry of spherical the equivalent or interocular differences in the RNFL and PCT were detected.ConclusionThe PCT did not differ significantly between the right and left eyes, although interocular asymmetry of the RNFL existed in this Chinese population with isometropia.

The Influence of Optical Coherence Tomography Measurements of Retinal Nerve Fiber Layer on Decision-Making in Glaucoma Diagnosis

ABSTRACTPurpose: To quantify the influence of spectral domain optical coherence tomography (SDOCT) on decision-making in patients with suspected glaucoma.Methods: A prospective cross-sectional study involving 40 eyes of 20 patients referred by community optometrists due to suspected glaucoma. All patients had disc photographs and standard automated perimetry (SAP), and results were presented to 13 ophthalmologists who estimated pre-test probability of glaucoma (0–100%) for a total of 520 observations. Ophthalmologists were then permitted to modify probabilities of disease based on SDOCT retinal nerve fiber layer (RNFL) measurements (post-test probability). The effect of information from SDOCT on decision to treat, monitor, or discharge was assessed. Agreement among graders was assessed using intraclass correlation coefficients (ICC) and correlated component regression (CCR) was used to identify variables influencing management decisions.Results: Patients had an average age of 69.0 ± 10.1 years, SAP mean deviation of 2.71 ± 3.13 dB, and RNFL thickness of 86.2 ± 16.7 μm. Average pre-test probability of glaucoma was 37.0 ± 33.6% with SDOCT resulting in a 13.3 ± 18.1% change in estimated probability. Incorporating information from SDOCT improved agreement regarding probability of glaucoma (ICC = 0.50 (95% CI 0.38 to 0.64) without SDOCT versus 0.64 (95% CI 0.52 to 0.76) with SDOCT). SDOCT led to a change from decision to “treat or monitor” to “discharge” in 22 of 520 cases and a change from “discharge” to “treat or monitor” in 11 of 520 cases. Pre-test probability and RNFL thickness were predictors of post-test probability of glaucoma, contributing 69 and 31% of the variance in post-test probability, respectively.Conclusions: Information from SDOCT altered estimated probability of glaucoma and improved agreement among clinicians in those suspected of having the disease.

Modeling the Chronic Loss of Optic Nerve Axons and the Effects on the Retinal Nerve Fiber Layer Structure in Primary Disorder of Myelin.

PurposeWe determined whether the chronic lack of optic nerve myelination and subsequent axon loss is associated with optical coherence tomography (OCT) changes in the retinal nerve fiber layer (RNFL), and whether this models what occurs in multiple sclerosis (MS) and confers its use as a surrogate marker for axon degeneration.MethodsUsing an animal model of Pelizaeus-Merzbacher disease (shp) bilateral longitudinal measurements of the peripapillary RNFL (spectral-domain OCT), electroretinograms (ERG), and visual evoked potentials (VEP) were performed in affected and control animals from 5 months to 2 years and in individual animals at single time points. Light and electron microscopy of the optic nerve and retina and histomorphometric measurements of the RNFL were compared to OCT data.ResultsOf the shp animals, 17% had an average reduction of OCT RNFL thickness on the superior retinal quadrant compared to controls (P < 0.05). Electroretinograms showed normal photopic A- and B-waves but flash VEPs were disorganized in shp animals. Morphologically, the shp retinas and optic nerves revealed significant RNFL thinning (P < 0.001) without retinal ganglion cell (RGC) loss, decrease total and relative retinal axonal area, and loss of optic nerve axons. There was strong positive correlation between OCT and morphometric RNFL thickness measurements (r = 0.878, P = 0.004).ConclusionThe loss of optic nerve axons demonstrated in the shp model resulted in moderate thinning of the RNFL confirmed by OCT and histology. These results indicate that OCT-derived RNFL measurement can be a useful surrogate biomarker of optic nerve axon loss and potentially disease progression in demyelinating diseases.

Visual dysfunction and retinal changes in patients with multiple sclerosis

PurposeTo evaluate structural changes in the retina and their correlation with visual dysfunction in patients with multiple sclerosis.MethodsPatients with multiple sclerosis (n = 84) and healthy controls (n = 84) underwent structural evaluation of the retinal nerve fiber layer, and macular and ganglion cell layer thicknesses using Spectral domain optical coherence tomography (SD‐OCT). All subjects underwent high and low contrast visual acuity, color vision (using the Farnsworth and L′Anthony desaturated D15 color tests), and contrast sensitivity vision using the Pelli Robson chart and CSV 1000E test.ResultsMacular, retinal nerve fiber layer, and ganglion cell layer thinning was observed in multiple sclerosis patients compared to healthy controls (p &lt; 0.05). High and low contrast visual acuity and contrast sensitivity vision at four different spatial frequencies were significantly reduced, compared with healthy subjects (p &lt; 0.05). Macular, retinal nerve fiber layer and ganglion cell layer measurements correlated with high and low contrast visual acuity, and contrast sensitivity vision. Contrast sensitivity vision was the functional parameter that most strongly correlated with the structural measurements in multiple sclerosis and was associated with ganglion cell layer measurements. The L′Anthony color vision score (age‐corrected color confusion index) was associated with macular measurements.ConclusionsPatients with multiple sclerosis had visual dysfunction that correlated with structural changes evaluated by SD‐OCT. Macular and ganglion cell layer measurements may be good indicators of visual impairment in multiple sclerosis patients.

Epiretinal membrane as a source of errors during the measurement of peripapillary nerve fibre thickness using spectral-domain optical coherence tomography (SD-OCT).

We aimed to examine the extent to which measurement errors in the determination of retinal nerve fibre layer (RNFL) using spectral-domain optical coherence tomography (SD-OCT) occur in cases of epiretinal membrane and whether systematic deviations are found in the values obtained. A macular scan and a circumpapillary scan were performed on 97 eyes of 97 patients using SD-OCT. Group 1 comprised 53 patients with epiretinal membrane at an age of 70 ± 4.8years (median ± average absolute deviation). Group 2 consisted of 44 patients without any macular pathologies (median age 70 ± 5.8years). Differences in the thickness of the RNFL and segmentation errors in the detection of the RNFL were recorded quantitatively in both groups and checked for statistical significance using non-parametric tests. The median central retinal thickness in Group 1 was 357 ± 79μm (median ± average absolute deviation), and in Group 2 it was 270 ± 11μm (p < 0.001). The result of the quadrant-by-quadrant measurement of the average RNFL in Group 1 and Group 2, respectively, was: temporal 88 ± 17 and 73 ± 9μm, inferior 121 ± 17 and 118 ± 15μm, nasal 87 ± 15 and 89 ± 14μm and superior 115 ± 15 and 114 ± 9μm. Temporally, the difference was statistically significant (p < 0.001). Segmentation errors of the RNFL were found in 19 of 53 eyes (35.8%) in Group 1 and in no eyes (p < 0.001) in Group 2. In eyes with epiretinal membrane, measuring errors in the SD-OCT occur significantly more frequently than in eyes without any retinal pathologies. If epiretinal membrane and glaucoma are present simultaneously, the results of the automated RNFL measurement using SD-OCT should be critically scrutinised, even if no papillary changes are visible clinically.