Retinal Nerve Fiber Layer Values Research Articles

Scanning Laser Polarimetry Reveals Status of RNFL Integrity in Eyes with Optic Nerve Head Swelling by OCT

Optical coherence tomography (OCT) shows retinal nerve fiber layer (RNFL) thickening in optic nerve head (ONH) swelling, but does not provide information on acute axonal disruption. It was hypothesized that scanning laser polarimetry (SLP) compared with OCT might reveal the status of axon integrity and visual prognosis in acute RNFL swelling. Threshold perimetry, OCT, and SLP were used to prospectively study eyes with papilledema (24), optic neuritis (14), nonarteritic anterior ischemic optic neuropathy (NAION) (21), and ONH swelling (average RNFL value by OCT was above the 95th percentile of controls at presentation). Regional RNFL was judged reduced if the quadrant measurement was below the fifth percentile of controls. At presentation, average RNFL by OCT was similar for eyes with papilledema and NAION (P = 0.97), and reduced for optic neuritis. Average RNFL by SLP was slightly increased for papilledema and optic neuritis, and reduced for NAION (P = 0.02) eyes. The RNFL by SLP was reduced in at least one quadrant in 1 eye with papilledema, 1 eye with optic neuritis, and in 13 eyes with NAION. In NAION eyes, quadrants with reduced SLP had corresponding visual field loss that did not recover. By one month, eyes with NAION showed RNFL thinning by OCT (7/17 eyes) and by SLP (14/16 eyes) in contrast to optic neuritis (by OCT, 0/12, P = 0.006; and by SLP, 1/12, P = 0.0004). OCT and SLP revealed different aspects of RNFL changes associated with ONH swelling. OCT revealed thickening due to edema. SLP revealed a decrease in retardance in eyes with axonal injury associated with visual field loss, which is unlikely to recover.

Evaluation of the Nerve Fiber Layer and Macula in the Eyes of Healthy Children Using Spectral-Domain Optical Coherence Tomography

To determine the normative values of the peripapillary retinal nerve fiber layer (RNFL), macular thickness, and macular volume in healthy children using spectral-domain optical coherence tomography (SD-OCT) and analyze the correlation of such values with age, refraction error, and biometric measurements. Observational case series. This institutional study involved 107 eyes from 107 healthy pediatric patients (54 female, 53 male) with ages between 6 and 16 years. After the biometric measurements and refractive error values (in spherical equivalent) of the cases were obtained, the peripapillary RNFL, macular thickness, and macular volume values were calculated using the Spectralis OCT device. Among the study group, with an average age of 10.46 ± 2.94 years, the average axial length (AL) was 23.33 ± 0.89 mm; the average spherical equivalent (SE) value was -0.27 ± 0.99 diopter. The average peripapillary RNFL thickness was 106.45 ± 9.41 μm; the average macular thickness was 326.44 ± 14.17 μm; and the average macular volume was 0.257 ± 0.011 mm(3). The aforementioned OCT measurements were not significantly correlated with age, SE, or AL values (P > .05 for all). This study reports SD-OCT findings among healthy pediatric cases. SD-OCT can be reliably used for pediatric patients because of its short exposure time and high degree of image resolution.

Correlation of Frequency-doubling Perimetry With Retinal Nerve Fiber Layer Thickness and Optic Disc Size in Ocular Hypertensives and Glaucoma Suspects

To determine the structure-function correlation using frequency-doubling technology (FDT) perimetry and optical coherence tomography (OCT) in glaucoma suspects, and analyze their relationship to optic disc size. Sixty eyes of 60 ocular hypertensive patients (OHT) and 54 eyes of 54 subjects with optic disc features suspicious of glaucoma (disc suspects) with normal visual fields on Standard Achromatic Perimetry were recruited. All subjects underwent FDT perimetry using the N-30 program, and the mean deviation (FDT-MD) and FDT-pattern SD were computed. Average and inferior retinal nerve fiber layer (RNFL) thickness and disc area were measured on Stratus OCT. Pearson correlation coefficient was calculated among all the measurements. In disc suspects, FDT-MD correlated significantly with RNFL thickness measurements (P<0.001; P=0.003) and disc area (P<0.001). There was no correlation with the vertical cup-disc area ratio (VCDR) and FDT indices. In OHT, FDT-MD correlated significantly with average RNFL thickness (P=0.038), and there was a significant negative correlation between FDT-MD and the VCDR (0.042). The FDT-pattern SD negatively correlated with RNFL thickness measurements (P=0.008; P=0.03). The disc area correlated significantly with the average and inferior average RNFL thickness measurements in both groups of patients (P=0.029 and P=0.007; P=0.013 and P=0.013, respectively). In OHT, optic discs with larger VCDR and thinner RNFL had lower FDT-MD values. In disc suspects, smaller-sized discs had thinner RNFL and lower values of FDT-MD. FDT perimetry and OCT seem to be useful adjuncts to detect these eyes, which might warrant close follow-up to eventually detect glaucoma by Standard Achromatic Perimetry.

Primary retinal pathology in multiple sclerosis as detected by optical coherence tomography

Sir, We read the recent Brain publication by Saidha et al. (2011) with great interest. In their manuscript, the authors suggested that primary retinal pathology detectable by optical coherence tomography (OCT) defines a subset of patients with multiple sclerosis (Saidha et al ., 2011). This subgroup of patients, which they termed ‘macular thinning predominant phenotype’, was reported to exist in ∼10% of the entire multiple sclerosis cohort examined by spectral domain OCT (Cirrus) at the authors’ centres. The macular thinning predominant OCT phenotype was defined by a combination of average macular thickness below the 5th percentile, with ipsilateral normal average retinal nerve fibre layer (RNFL) thicknesses (between the 5th and 95th percentiles of RNFL values from the manufacturer's normative database), in one or both eyes, in the absence of a history of acute optic neuritis in affected eyes (Saidha et al ., 2011). Sixty-two per cent (31/50) of patients fulfilling the macular thinning predominant OCT criteria had a macular thickness below the 1st percentile. In addition, there was a remarkable male preponderance among patients with the macular thinning predominant phenotype (70% male versus 30% female), a difference that was even more pronounced (77.4% male versus 22.6% female) among those patients with very low macular thicknesses (<1st percentile). These in vivo findings are in line with a recent post-mortem analysis reporting retinal pathology in multiple sclerosis beyond damage to the RNFL and the ganglion cell layer (Green et al ., 2010). These data are intriguing in that they point to a novel concept of primary retinal damage in multiple sclerosis. They indicate that retinal pathology might not only develop as a consequence of inflammatory attacks to the anterior optic pathway causing …

Comparison of two retinal nerve fibre layer thickness measurement patterns of RTvue optical coherence tomography

To evaluate the agreement and repeatability between operator-dependent centring and automatic centring retinal nerve fibre layer thickness measurement patterns (RNFL3.45 and NHM4) of RTvue optical coherence tomography in normal and glaucomatous eyes. Cross-sectional observational study. A total of 153 eyes from 149 normal subjects and subjects with glaucoma were analysed. The retinal nerve fibre layer thickness was measured using RNFL3.45 and NHM4 three times on the same day to determine the repeatability and agreement between the two scan patterns. Student's paired t-testing, intra-class correlation coefficient, coefficient of variation, test-retest viability, Pearson's correlation coefficient and Bland-Altman analysis of retinal nerve fibre layer thickness measurements. The difference between RNFL3.45 and NHM4 measurements was statistically significant by paired t-testing (P=0.003) only in severe glaucoma group. The Pearson's correlation test showed a high degree of correlation of the mean retinal nerve fibre layer thickness (r=0.949). Bland-Altman plots showed that the differences between RNFL3.45 and NHM4 were smaller at thicker retinal nerve fibre layer values, but larger at thinner retinal nerve fibre layer values. The intra-class correlation coefficient for RNFL3.45 (and lower 95% confidence interval) in normal and glaucomatous eyes was 0.990 (0.985 confidence interval) and 0.997 (0.995 confidence interval), respectively. The intra-class correlation coefficient for NHM4 in normal and glaucomatous eyes was 0.989 (0.983 confidence interval) and 0.995 (0.992 confidence interval), respectively. The test-retest variability for RNFL3.45 and NHM4 ranged from 3.98 to 9.75µm in normal eyes, and from 4.10 to 13.34µm in glaucomatous eyes. Measurements of retinal nerve fibre layer thickness by RNFL3.45 and NHM4 are in good agreement.

Retinal nerve fibre layer thickness in full-term children assessed with Heidelberg retinal tomography and optical coherence tomography: normal values and interocular asymmetry

This study aimed to investigate normal values and interocular differences in retinal nerve fibre layer (RNFL) thickness, using optical coherence tomography (OCT) and Heidelberg retinal tomography (HRT), in 5-16-year-old children born at full-term with normal birthweights. Fifty-six children with normal visual acuity and refraction were examined with Stratus OCT and HRT. Three examinations were performed in each eye. One eye in each child was randomized for analyses of normal values. Findings in 54 eyes were evaluated. Mean values of RNFL thickness were calculated. Coefficients of variance and intraclass correlations were calculated. The correlation between right and left eyes and the limits of difference were determined for both methods. Mean RNFL thickness was 98.4 μm (standard deviation [SD] 7.88 μm) assessed with OCT and 213.0 μm (SD 54.0 μm) assessed with HRT. No correlations between age or gender and RNFL thickness were found. The coefficients of variance were 2.9% and 5.6% for OCT and HRT, respectively, and intraclass correlations were 0.85 and 0.88, respectively. The limits of difference between the two eyes ranged from -9 μm to 9 μm with OCT and from -109 μm to 87 μm with HRT. Both OCT and HRT can be used in children aged 5-16 years, but OCT provides less variability in determinations of RNFL thickness, both in repeated examinations of the same eye and in comparisons between the two eyes. The present study provides values for normal RNFL thickness in healthy children which can be used to make comparisons with values in children with optic nerve diseases.

Influence of atypical retardation pattern on the peripapillary retinal nerve fibre distribution assessed by scanning laser polarimetry and optical coherence tomography

AimTo investigate the influence of atypical retardation pattern (ARP) on the distribution of peripapillary retinal nerve fibre layer (RNFL) thickness measured with scanning laser polarimetry in healthy individuals and to...

Exploring the Association between Retinal Nerve Fiber Layer Thickness and Initial Magnetic Resonance Imaging Findings in Patients with Acute Optic Neuritis

Background. Recent studies have shown that OCT-measured retinal nerve fiber layer (RNFL) values may represent a marker for axonal damage in the anterior visual pathway of optic neuritis (ON) and multiple sclerosis (MS) patients. The goal of this study was to determine the link between RNFL values and initial magnetic resonance imaging (MRI) evidence of central nervous system (CNS) inflammation in patients with acute ON. Methods. Fifty patients who experienced ON as a clinically isolated syndrome (CIS) were followed for a mean period of 34 months with OCT testing. RNFL values in affected (ON) eyes and clinically unaffected (non-ON) eyes were compared between patients with MRI evidence of white matter lesions and those with normal baseline MRI findings, over a two year period. Findings. Twenty-one patients (42%) developed clinically definite MS (CDMS) during the study. After two years, temporal RNFL values were thinner (P = .07) in ON patients with MRI lesions at baseline, but the results were not significant. Conclusions. There is no association between RNFL values and baseline MRI status in ON patients at risk for future CDMS over a two year period.

Reproducibility and agreement in evaluating retinal nerve fibre layer thickness between Stratus and Spectralis OCT.

To evaluate intra-device reproducibility of retinal nerve fibre layer (RNFL) measurements obtained using Stratus and Spectralis optical coherence tomography, and to analyze inter-device correlation and agreement for these measurements. Prospective observational study. A total of 30 normal individuals participated in the study. One eye of each participant was scanned three times during one session by the same operator using Spectralis and Stratus. Intra-class correlation coefficients (ICCs), correlation coefficients (R), and Bland-Altman plots (BAPs) were used to assess reproducibility, correlation, and agreement between the two devices, respectively. A significant difference in mean RNFL thickness was seen between Stratus and Spectralis (106.2 ± 6.9 μm vs 100.0 ± 7.3 μm, P = 0.0001). ICCs of RNFL thickness measurements ranged from 0.69 (clock hour 2; 95% confidence interval (95% CI): 0.54, 0.85) to 0.91 (inferior quadrant; 95% CI: 0.86, 0.96) for Stratus and were higher for Spectralis, ranging from 0.87 (temporal-superior sector; 95% CI: 0.79, 0.94) to 0.96 (global and nasal-inferior sector; 95% CI: 0.94, 0.99). Rs of RNFL thickness measurements between the two instruments ranged from 0.61 (temporal quadrant) to 0.87 (superior quadrant). BAPs demonstrated a systematic difference in RNFL values between the two devices, with Spectralis producing thinner RNFL values than Stratus. Spectralis demonstrated higher ICCs and thinner RNFL measurements than Stratus. Although the inter-device correlation was good, differences in RNFL measurements obtained by the two devices indicate that these measurements would not be interchangeable in clinical evaluations.

Quantification of Retinal Nerve Fiber Layer Thickness in Normal Eyes, Eyes with Ocular Hypertension, and Glaucomatous Eyes with SD-OCT

To quantitatively evaluate and compare retinal nerve fiber layer (RNFL) thickness between normal eyes, eyes with ocular hypertension (OHT), and glaucomatous eyes in an Indian population using spectral domain optical coherence tomography (SD-OCT). Average and quadrant RNFL values were compared among three groups (66 normal eyes, 55 OHT eyes, and 51 glaucomatous eyes) and the discriminating power of each parameter was evaluated by calculating areas under receiver operator curves (AROCs). The mean RNFL thickness was 93.45 ± 16.9 μm in glaucomatous eyes, significantly less than in normal (112.48 ± 6.8 μm) and OHT (110.09 ± 10.9 μm) eyes. OHT eyes had significantly thinner RNFL thickness in the temporal quadrant (P = .006) than normal eyes. RNFL thickness in glaucomatous eyes differed significantly from normal eyes in most parameters except nasal quadrant (P = .1) and from OHT eyes in most parameters except temporal (P = .4) and nasal quadrants (P = .3). The parameter with the largest AROC to discriminate between OHT and normal eyes was temporal quadrant (0.65). Inferior quadrant RNFL thickness had the largest AROC (0.93) to distinguish between OHT and glaucomatous eyes and normal and glaucomatous eyes. SD-OCT identified differences in most parameters between eyes with glaucoma and normal eyes and also between eyes with glaucoma and OHT. Overlap of RNFL thickness between normal and OHT eyes limits the ability of this instrument to differentiate between normal and OHT subjects.

Comparison of Retinal Nerve Fiber Layer Thickness in Normal Eyes Using Time-Domain and Spectral-Domain Optical Coherence Tomography

To compare retinal nerve fiber layer (RNFL) thickness measurements between 3 different spectral-domain optical coherence tomography (SD-OCT) instruments (Spectralis; Heidelberg Engineering; Cirrus; Carl Zeiss Meditec; RTVue; Optovue, Inc) and one time-domain OCT (Stratus; Carl Zeiss Meditec). Prospective, cross-sectional study. RNFL thickness was measured on both eyes of 40 normal subjects using Stratus, Spectralis, RTVue, and Cirrus OCT on the same day. Scans were repeated 2 to 8 weeks later in the same fashion. Agreement with Stratus was evaluated for each SD-OCT and intervisit reproducibility was assessed for all machines. Mean RNFL thickness determined by each of the 3 SD-OCT instruments was highly correlated with Stratus (r = 0.87-0.91). The mean RNFL thickness (mean ± standard deviation) was 110.1 ± 12.8 μm for Stratus, 106.6 ± 12.8 μm for Spectralis, 98.7 ± 10.9 μm for Cirrus, and 112.8 ± 13.2 μm for RTVue. The average differences between each SD-OCT and Stratus for mean RNFL thickness were all statistically significant (P ≤ .001), as were most quadrant measurements. All 4 instruments demonstrated excellent intraclass correlation coefficient values for mean RNFL thickness (0.90-0.97). However, intervisit variability was lowest for RTVue as evidenced by reproducibility values, followed by Stratus, Cirrus, and Spectralis (6.59, 8.83, 8.89, and 11.72 μm, respectively). RNFL measurements taken with Spectralis, RTVue, and Cirrus all have excellent correlation to Stratus, with good reproducibility in normal eyes. Despite high correlations, RNFL values are significantly different between instruments and should not be used interchangeably.

Using retinal architecture to help characterize multiple sclerosis patients

Objective: We compared retinal nerve fibre layer (RNFL) thickness and visual function in a heterogeneous multiple sclerosis (MS) cohort to determine whether optical coherence tomography (OCT) may complement the existing methods used to characterize MS patients. Design: Cross-sectional cohort study. Participants: One hundred and ninety-three patients with optic neuritis (ON) as a clinically isolated syndrome (CIS) ( n = 63), relapsing-remitting MS (RRMS) ( n = 108), secondary progressive MS (SPMS) ( n = 13), and primary progressive MS (PPMS) ( n = 9). Methods: All patients underwent standardized ophthalmic, neurological, and OCT testing at a single academic institution. Results: RNFL values were reduced in PPMS (94.3 μm), RRMS (99.6 μm), and SPMS eyes (84.7 μm) relative to CIS eyes (105.7 μm) ( p < 0.0001). RNFL values were lower in eyes with recurrent ON (64.2 μm) relative to eyes affected by a single ON event (86.3 μm) ( p < 0.0001). The strongest correlation between RNFL thickness and neurological disability occurred in RRMS patients ( r = −0.51, p < 0.0001). RNFL thickness correlated with visual field sensitivity for CIS ( r = 0.23, p < 0.01) and RRMS ( r = 0.22, p < 0.01) patients. Simple linear regression showed that every 10 μm decrease in RNFL correlated with a 5.8 decibel decrease in visual field sensitivity (adjusted R 2 = 0.35, p < 0.0001) for RNFL values less than 75 μm. Conclusions: There were robust correlations between RNFL thickness and visual function, particularly in ON eyes. OCT may complement the existing tools used to characterize MS patients, but further studies are needed.

Retinal Nerve Fiber Layer Thickness in Normal Hong Kong Chinese Children Measured With Optical Coherence Tomography

To obtain the retinal nerve fiber layer (RNFL) thickness normative values of Hong Kong children by using optical coherence tomography (OCT) and to investigate the effect of age and axial length (AL) on RNFL thickness. One hundred and four normal children aged between 6 and 17 years were recruited for this study. The RNFL thickness was measured by OCT (Stratus OCT). AL was measured by the IOLMaster. The median age of our subjects was 9.75 years (range: 6.08 to 17.58 years). The mean full circle peripapillary RNFL (RNFL-FC) was 113.5 microm (SD 9.8) and 113.1 microm (SD 10.8) in the right and left eyes, respectively. Multiple linear regression analysis showed a significant negative correlation between AL and RNFL-FC in both the right (r=-0.23, P<0.05) and left eyes (r=-0.25, P<0.05). The effect was the strongest in the superior quadrant. Every 1 mm increase in AL would result in a decrease in RNFL-FC by 2.7 to 2.9 microm. Age did not show significant effect on RNFL-FC. This study provides normative RNFL values for Hong Kong Chinese children. It can be used as a reference for the screening of glaucoma in children. AL demonstrates a significant negative correlation with RNFL thickness.

Comparison of Scanning Laser Polarimetry and Optical Coherence Tomography in Quantitative Retinal Nerve Fiber Assessment

To investigate the relationship between retinal nerve fiber layer (RNFL) measurements in corresponding areas obtained with scanning laser polarimetry and optical coherence tomography and to compare their discriminating ability in the diagnosis of preperimetric and perimetric glaucoma. Three hundred eighty-six subjects-57 healthy controls, 145 ocular hypertensive patients, 89 with preperimetric glaucoma, and 95 with perimetric glaucoma-were recruited from the Erlangen Glaucoma Registry. Perimetry, 24-hours intraocular pressure profile, stereographic optic disc slides, optical coherence tomography StratusOCT, and scanning laser polarimetry GDx VCC (Carl Zeiss Meditec, Inc, Dublin, CA) were performed in all patients. Receiver operating characteristic (ROC) curves were constructed for mean RNFL values, sector data, and indices. Sensitivity was estimated at >or=90% and >or=80% of specificity to compare the discriminating ability of each imaging modality. For discrimination between glaucomatous and healthy eyes in GDx VCC the nerve fiber index demonstrated the largest area under the ROC curve (AUROC) (0.962+/-0.013), whereas in StratusOCT the largest AUROC (0.986+/-0.006) was found in the inferior quadrant. For preperimetric glaucoma detection the nerve fiber index achieved the largest AUROC (0.783+/-0.037). In contrast, the total RNFL average obtained using StratusOCT showed the largest AUROC (0.904+/-0.025). Bland-Altman plots showed good agreement between both instruments. Both the GDx VCC and StratusOCT demonstrate increasing RNFL loss with advanced glaucomatous damage and were comparable in the diagnosis of perimetric glaucoma. Preperimetric glaucomatous damage may be better assessed by StratusOCT.

Glaukomdiagnostik mittels Scanning-Laser-Polarimetrie

Scanning laser polarimetry (SLP) is another technology for early glaucoma diagnosis. This technique (represented in the GDx from Carl Zeiss Meditec, Jena, Germany) is based on polarimetry and measures the retinal nerve fiber layer (RNFL) thickness. Compared with previous instruments without customized corneal compensation, the variable corneal compensation technology enables improved differentiation between glaucoma and healthy eyes. Limitations are the atypical birefringence patterns that exist in some eyes, showing false high RNFL values. The newest software uses enhanced corneal compensation (ECC) technology to avoid these atypical patterns and to improve glaucoma diagnosis. Advantages of SLP include independence from drawing a contour line and a reference plane. Follow-up using SLP is limited, but with the use of the new ECC technology, trend and event analyses are possible. Long-term studies will determine the effectiveness of this method.

Comparison of Retinal Nerve Fiber Layer Measurements Using Time Domain and Spectral Domain Optical Coherent Tomography

To determine the agreement between peripapillary retinal nerve fiber layer (RNFL) thickness measurements from Stratus time domain optical coherence tomography (OCT) and Cirrus spectral domain OCT (Carl Zeiss Meditec, Dublin, CA) in normal subjects and subjects with glaucoma. Evaluation of diagnostic test or technology. A total of 130 eyes from 130 normal subjects and subjects with glaucoma were analyzed. The subjects were divided into groups by visual field criteria: normal (n = 29), glaucoma suspect (n = 12), mild glaucoma (n = 41), moderate glaucoma (n = 18), and severe glaucoma (n = 30). Peripapillary RNFL thickness was measured with Stratus Fast RNFL and Cirrus 200 x 200 Optic Disc Scan on the same day in 1 eye of each subject to determine agreement. Two operators used the same instruments for all scans. Student paired t testing, Pearson's correlation coefficient, and Bland-Altman analysis of RNFL thickness measurements. The average age of the glaucoma group was significantly more than that of the normal group: 68.3+/-12.3 years versus 55.7+/-12.1 years, respectively. For Stratus OCT, the average RNFL thickness (mean +/- standard deviation) was 99.4+/-13.2 microm, 94.5+/-15.0 microm, 79.0+/-14.5 microm, 62.7+/-10.2 microm, and 51.0+/-8.9 microm for the normal, suspect, mild, moderate, and severe groups, respectively. For Cirrus OCT, the corresponding measurements were 92.0+/-10.8 microm, 88.1+/-13.5 microm, 73.3+/-11.8 microm, 60.9+/-8.3 microm, and 55.3+/-6.6 microm. All Stratus-Cirrus differences were statistically significant by paired t testing (P<0.001) except for the moderate group (P = 0.11). For average RNFL, there was also a highly significant linear relationship between Stratus minus Cirrus difference and RNFL thickness (P<0.001). Bland-Altman plots showed that the systematic difference of Stratus measurements are smaller than Cirrus at thinner RNFL values but larger at thicker RNFL values. RNFL thickness measurements between Stratus OCT and Cirrus OCT cannot be directly compared. Clinicians should be aware that measurements are generally higher with Stratus than with Cirrus except when the RNFL is very thin, as in severe glaucoma. This difference must be taken into account if comparing Stratus measurements with Cirrus measurements.

Differences in retinal nerve fiber layer atrophy between multiple sclerosis subtypes

Objectives To determine whether retinal nerve fiber layer (RNFL) atrophy in the afferent visual pathway may complement existing tools used to describe and characterize differences across MS subtypes. Methods Optical coherence tomography-measured RNFL values were compared over two years in 35 patients (70 eyes) with optic neuritis (ON) as a clinically isolated syndrome (CIS); 39 patients (78 eyes) with relapsing remitting MS (RRMS); and 7 patients (14 eyes) with secondary progressive MS (SPMS). Results RNFL comparisons involving eyes without ON yielded greater differences between MS subtypes than ON-affected eyes. Overall RNFL values in non-affected eyes were reduced in SPMS patients (83.4 μm), relative to CIS (101.2 μm) ( p = 0.0009), and RRMS patients (103.7 μm) ( p = 0.001); and temporal RNFL atrophy was greater in RRMS (64.4 μm) eyes as compared to CIS eyes (73.2 μm) ( p = 0.02). In ON-affected eyes, RNFL atrophy was greater in SPMS patients (39.5 μm) than CIS patients (58.1 μm) ( p = 0.03), and in RRMS patients (48.2 μm) relative to CIS patients ( p = 0.05). RNFL values did not change significantly for any MS subtype during the two-year duration of the study. Interpretation RNFL thickness may represent a structural marker, which can help distinguish MS subtypes, because the extent of atrophy is commensurate with disease progression. RNFL comparisons between non-affected eyes revealed greater differences between CIS, RRMS, and SPMS patients relative to ON-affected eyes, because the impact of prior ON may supplant the effects of disease subtype.

The relationship between Rarebit perimetry and OCT‐derived retinal nerve fibre layer thickness in glaucoma

To examine the association between measures of neuroretinal matrix integrity as determined with Rarebit perimetry and optical coherence tomography (OCT)-derived retinal nerve fibre layer thickness. One randomly selected eye of 30 White primary open-angle glaucoma patients (age: 60.9 +/- 11.7 years; MD: -3.2 +/- 5.1 dB) and 16 healthy White individuals (age: 33.2 +/- 6.4 years; MD: -0.8 +/- 0.8 dB) were included in the study. Participants underwent Rarebit perimetry testing (central field, software version 4) and an OCT fast retinal nerve fibre layer (RNFL) scan. Correlation was investigated between hemifield Rarebit scores and the corresponding RNFL values, as well as between global Rarebit scores and the respective RNFL measures. Statistically significant correlations of average hit rate (HR) < 90 and mean hit rate (MHR) were detected with Max-Min and average thickness (Pearson's r ranging from 0.393 to 0.474). Number HR < 90 showed a moderate correlation only with Max-Min (r = -0.396, P = 0.030). Regarding the association between hemifield hit rates and the corresponding OCT thickness parameters, only inferior maximum correlated moderately with HR superior (r = 0.385, P = 0.035). A tendency was detected for the relationship of superior maximum with HR inferior (r = 0.345, P = 0.062). For the control group, no significant correlation was found for any of the global or hemifield indices and the corresponding thickness values. Although Rarebit perimetry is based on a physiological principle distinctly different from conventional perimetry, it provides global indicators of neuroretinal matrix integrity that correlate with some OCT-derived RNFL thickness measures.

Retinal Nerve Fiber Layer and Future Risk of Multiple Sclerosis

Optical coherence tomography (OCT)--measured retinal nerve fiber layer (RNFL) values may represent a surrogate biomarker for axonal integrity in multiple sclerosis (MS). The purpose of this study was to determine whether RNFL measurements obtained within two years of an optic neuritis (ON) event distinguish patients at increased risk of developing clinically-definite MS (CDMS). Fifty consecutively sampled patients who experienced a single ON event were followed prospectively for a mean period of 34 months with OCT testing. Values of RNFL in clinically-affected and non-affected eyes were compared between patients who developed CDMS and those that did not develop MS after ON. Twenty-one patients (42%) developed CDMS during the course of the study, with a mean conversion time of 27 months. Mean RNFL values were thinner in the clinically-affected eyes of non-MS patients than CDMS eyes after one year (p = 0.0462) due to more severe ON events in the former. By year two, CDMS patients manifested more recurrent ON events and RNFL thinning than non-MS patients. Temporal RNFL values were thinner in the non-affected eyes of CDMS patients with a trend towards significance (p = 0.1302). Our results indicate that RNFL thickness does not reliably distinguish patients at higher risk of converting to CDMS after ON. The severity of ON has a greater effect on RNFL thickness than risk of CDMS at one year. The CDMS patients demonstrate progressive RNFL thinning likely due to recurrent sub-clinical ON events, which may help differentiate them from non-MS patients over time.

Comparison of retinal nerve fiber layer measurements using Stratus OCT fast and regular scan protocols in eyes with band atrophy of the optic nerve and normal controls

To compare retinal nerve fiber layer (RNFL) measurements made with two different protocols of optical coherence tomography in eyes with band atrophy (BA) of the optic nerve and controls. Twenty-nine eyes with BA from chiasmal compression and 30 normal eyes underwent RNFL scans using both the fast (256 A-scans) and the regular (512 A-scans) protocols. The two sets of measurements were compared. In eyes with BA, fast RNFL measurements were significantly greater compared with regular RNFL measurements in the superior and inferior quadrants and significantly smaller at the 30-degree segments located at the 3 and 6 o'clock meridians. In normal eyes, fast RNFL measurements of the total average, superior and inferior quadrants and the segments corresponding to the 1, 3, 4 and 12 o'clock meridians were significantly greater than regular protocol measurements. Measurements with both protocols were significantly different in eyes with BA compared to normal eyes. Although both fast and regular RNFL measurements were equally efficient at differentiating eyes with BA from controls the fast protocol yielded greater values in areas with thick RNFL and smaller values in areas with thin RNFL when compared with the regular scanning protocol. One should be aware of such differences when comparing measurements with both scanning protocols.