Fast Retinal Nerve Fiber Layer Thickness Research Articles

Comparison of Machine Learning Methods Using Spectralis OCT for Diagnosis and Disability Progression Prognosis in Multiple Sclerosis

Machine learning approaches in diagnosis and prognosis of multiple sclerosis (MS) were analysed using retinal nerve fiber layer (RNFL) thickness, measured by optical coherence tomography (OCT). A cross-sectional study (72 MS patients and 30 healthy controls) was used for diagnosis. These 72 MS patients were involved in a 10-year longitudinal follow-up study for prognostic purposes. Structural measurements of RNFL thickness were performed using different Spectralis OCT protocols: fast macular thickness protocol to measure macular RNFL, and fast RNFL thickness protocol and fast RNFL-N thickness protocol to measure peripapillary RNFL. Binary classifiers such as multiple linear regression (MLR), support vector machines (SVM), decision tree (DT), k-nearest neighbours (k-NN), Naïve Bayes (NB), ensemble classifier (EC) and long short-term memory (LSTM) recurrent neural network were tested. For MS diagnosis, the best acquisition protocol was fast macular thickness protocol using k-NN (accuracy: 95.8%; sensitivity: 94.4%; specificity: 97.2%; precision: 97.1%; AUC: 0.958). For MS prognosis, our model with a 3-year follow up to predict disability progression 8 years later was the best predictive model. DT performed best for fast macular thickness protocol (accuracy: 91.3%; sensitivity: 90.0%; specificity: 92.5%; precision: 92.3%; AUC: 0.913) and SVM for fast RNFL-N thickness protocol (accuracy: 91.3%; sensitivity: 87.5%; specificity: 95.0%; precision: 94.6%; AUC: 0.913). This work concludes that measurements of RNFL thickness obtained with Spectralis OCT have a good ability to diagnose MS and to predict disability progression in MS patients. This machine learning approach would help clinicians to have valuable information.

Optical coherence tomography in the evaluation of structural changes in primary open-angle glaucoma with and without elevated intraocular pressure.

Glaucoma is a progressive optic neuropathy characterized by damage of the retinal ganglion cells and their axons and glial cells. The aim of this study was to evaluate the differences and connections between changes in the visual field and the thickness of the peripapillary retinal nerve fiber layer (RNFL), using optical coherence tomography (OCT) in patients with primary open-angle glaucoma with normal and elevated intraocular pressure (IOP). This prospective study included 38 patients (38 eyes) with primary open-angle glaucoma with normal intraocular pressure (NTG) and 50 patients (50 eyes) with primary open-angle glaucoma with elevated intraocular pressure (HTG), paired by the same degree of structural glaucomatous changes in the optic nerve head and by age. OCT protocols ’fast RNFL thickness’ and ’fast optic disc’ were used for testing. The patients’ age, gender, best corrected visual acuity (BCVA), IOP, stereometric and functional parameters were compared. The average age of the examined population was 65.49 ± 9.36 (range 44-83) years. There was no statistically significant difference by age and by gender between the two study groups (p = 0.795 and p = 0.807, respectively). BCVA was higher in patients with NTG but there was no statistically significant difference compared to HTG patients (p = 0.160). IOP was statistically significantly higher in patients with HTG compared to NTG patients (17.40 ± 2.77 mmHg vs 14.95 ± 3.01 mmHg, p = 0.009). The cup/disc (C/D) (p = 0.258), mean deviation (MD) (p = 0.477), corrected patern standard deviation (CPSD) (p = 0.943), disk area (p = 0.515), rim area (p = 0.294), rim volume (p = 0.118), C/D area R (p = 0.103), RNFL Average (p = 0.632), RNFL Superior (p = 0.283) and RNFL Inferior (p = 0.488) were not statistically significantly different between the groups. OCT measurements of the RNFL thickness provide clinically significant information in monitoring of glaucomatous changes. There are no differences in the patterns of RNFL defects per sectors and quadrants between NTG and HTG, measured by OCT.

Evaluation of the effect of intravitreal ranibizumab injections in patients with neovascular age related macular degeneration on retinal nerve fiber layer thickness using optical coherence tomography.

PurposeTo evaluate the effect of repeated intravitreal ranibizumab injections for neovascular age related macular degeneration (nAMD) on the retinal nerve fiber layer (RNFL) thickness using optical coherence tomography.DesignA prospective observational cohort study of patients with nAMD.MethodsThirty eyes of 30 patients with nAMD were selected. All patients received three ranibizumab injections and underwent scans using the fast RNFL thickness protocol (Stratus optical coherence tomography) before starting the first injection and 1 month after the third injection. The RNFL thickness measurements prior to the injections and after the third injection were used for the analysis. We also evaluated the effect of the lens status as well as the type of choroidal neovascular membrane on RNFL thickness measurements pre- and post-injection. Pre- and post-injection average and individual quadrant RNFL thickness were measured and statistically analyzed.ResultsThe mean (± standard deviation) pre-injection RNFL thickness was 90.8±18. The mean (± standard deviation) post-injection RNFL thickness was 91.03±15. The pre- and post-injection values of the mean RNFL thickness were not statistically significant. Likewise, the pre- and post-injection values for RNFL thickness in the different quadrants were not statistically significant. There was no statistical significance for the lens status or the type of choroidal neovascular membrane on the RNFL thickness.ConclusionRepeated ranibizumab injections in nAMD appear to have no harmful effect on the RNFL thickness in the short term, in spite of the proven neurotrophic effect of vascular endothelial growth factor. Nevertheless, the safety profile of ranibizumab injections in nAMD needs to be further evaluated in a large multicenter trial with special emphasis on the long-term effects on the retina and optic nerve.

Macula and Retinal Nerve Fiber Layer in Migraine Patients: Analysis By Spectral Domain Optic Coherence Tomography

Aim: Investigating the retinal nerve fiber layer (RNFL), macular and ganglion cell complex thickness in eyes of migraine patients using optical coherence tomography. Methods: The study was designed as an observational cross-sectional study. 50 patients with migraine (30 patients with aura and 20 patients without aura) and 50 healthy volunteers were included. Optical coherence tomography was performed with Optovue technology. The fast RNFL thickness (3.4) scan, MM5, and GCC acquisition protocols were used. Results: There was no statistically significant difference in retinal thickness in any of the quadrants between the control group and the migraine patients (p > 0.05). The average RNFL thickness (110.50 vs 102.84 microns, p = 0.03) was significantly thinner in migrainers as compared to the control. The ANOVA did not reveal any significant difference between migrainers with aura, migrainers without aura, and the control group. The VAS (visual analogue scale) score of migraine patients was not statistically significantly correlated with any of the parameters, while the length of migraine history was negatively correlated with the average RNFL thickness (r = −0.32, p = 0.03). Conclusıon: The average RNFL thickness in the migraine patients was found to be thinner than that in the control group. In addition, we found a negative weak correlation between length of migraine history and the average RNFL thickness, supporting the possible association between these pathologies.

Prognostic determination using optical coherence tomography compared with visual functions in optic neuritis

Background: The majority of optic neuritis patients often notice improvement and gain stability of their visual functions, however, evidences of ongoing retinal nerve fiber layer (RNFL) thinning have been reported. Purposes: To investigate the correlation between RNFL thickness measured with Optical coherence tomography (OCT) and visual function tests and to determine the utility of OCT in visual prognostic assessment of optic neuritis. Method: A prospective study was performed in 12 patients with acute isolated optic neuritis. Best corrected visual acuity (BCVA), Swedish interactive threshold algorithms (SITA) 30-2 strategy on Humphrey field analyzer, and fast RNFL thickness analysis were performed on both affected and fellow eyes at baseline, 1.5, three and six months. Results: Mean BCVA and average mean deviation (MD) of the affected eye were significantly different from the fellow eyes at baseline. Affected eyes had significant thinner of RNFL at baseline, 1.5, three, and six months. Significant correlations between (i) mean RNFL thickness and BCVA at 1.5 ( r = 0.707, p = .010), (ii) mean RNFL thickness and MD at 1.5 months ( r = 0.674, p = .016) and six months( r = 0.710, p = .032), (iii) mean RNFL thickness at 1.5 months and MD at six months ( r = 0.782, p = .013). Conclusion: A correlation between RNFL thickness and visual function tests indicates that OCT might have roles in detection and prediction of RNFL damage in Optic neuritis (ON) patients despite no evidence of MS.

Comparison of Sensitivities for Detecting Diffuse and Localized Retinal Nerve Fiber Layer Defects With Time-domain Optical Coherence Tomography in Patients With Glaucoma

To compare the ability of time-domain optical coherence tomography (OCT) to detect diffuse and localized retinal nerve fiber layer (RNFL) defects using a built-in normative database in patients with early to moderate glaucoma. Subjects with localized visual field defects confined to either hemifield were consecutively recruited. Only 1 eye per subject was considered. Among the 91 eyes with localized RNFL defects, 46 eyes with mean deviations matched to those of the 46 eyes with diffuse RNFL defects were selected for statistical analysis. This case-control study included 46 eyes with diffuse RNFL defects and 46 eyes with localized RNFL defects. The fast RNFL thickness protocol of Stratus OCT was used. The clock-hour and quadrant sector parameters corresponding to the hemifield with the visual field defect were evaluated at P<0.05 with regard to the built-in normative database. The sensitivities of these parameters were compared between diffuse and localized RNFL defects. The sensitivity of the clock-hour sector parameter for diffuse RNFL defects (84.8%) was not significantly different than that for localized RNFL defects (80.4%) (P=0.78). The sensitivity of the quadrant sector parameter for diffuse RNFL defects (74.9%) was significantly higher than that for localized RNFL defects (52.3%) (P=0.04). The clock-hour parameter of time-domain OCT detected RNFL defects without significant difference in sensitivities between diffuse and localized patterns of RNFL loss in glaucomatous eyes. However, the quadrant parameter of OCT showed better sensitivity for diffuse RNFL defects than for localized RNFL defects.

Short-term use of inhaled and intranasal corticosteroids is not associated with glaucoma progression on optical coherence tomography

To compare the changes in retinal nerve fiber layer (RNFL) thickness and optic nerve cup/disc ratio on optical coherence tomography (OCT) between users and nonusers of inhaled and intranasal corticosteroids (ICS). Retrospective study of participants with glaucoma or glaucoma suspect having 2 or more OCTs during a 6-year period. The rates of change in Stratus OCT fast RNFL thickness scan and fast optic disc scan data were compared between ICS users and nonuser controls using random coefficient models. A total of 170 participants met the inclusion criteria, of whom 42 (25%) were ICS users and 128 (75%) were controls. The mean duration of follow-up was 3.2 years. There were no significant differences in the mean rates of change in superior RNFL (-0.8874 µm/y ICS users; -0.8592 µm/y controls; p=0.943), nasal RNFL (-0.0529 µm/y ICS users; -0.3577 µm/y controls; p=0.419), inferior RNFL (0.2703 µm/y ICS users; -0.1910 µm/y controls; p=0.165), and temporal RNFL (-0.3618 µm/y ICS users; -0.3612 µm/y controls; p=0.998) between ICS users and controls. There were no significant differences in the mean rates of change in horizontal cup/disc ratio (-0.0047 µm/y ICS users; 0.0002 µm/y controls; p=0.212) and vertical cup/disc ratio (0.0013 µm/y ICS users; 0.0029 µm/y; p=0.717) between ICS users and controls. We found no significant difference in the rates of RNFL or optic nerve cup/disc ratio progression among individuals with glaucoma or glaucoma suspect following short-term ICS use.

Retinal Nerve Fiber Layer Thickness in Children With Optic Pathway Gliomas

To determine the relationship of high-contrast visual acuity (VA) and low-contrast letter acuity with retinal nerve fiber layer (RNFL) thickness in children with optic pathway gliomas. Cross-sectional convenience sample, with prospective data collection, from a tertiary care children's hospital of patients with optic pathway gliomas associated with neurofibromatosis type 1, sporadic optic pathway gliomas, and neurofibromatosis type 1 without optic pathway gliomas. Patients underwent best-corrected VA testing using surrounded H, O, T, V optotypes and low-contrast letter acuity (5%, 2.5%, and 1.25% low-contrast Sloan letter charts). Mean RNFL thickness (micrometers) was measured by a Stratus optical coherence tomography device (Carl Zeiss Meditec) using the fast RNFL thickness protocol. Eyes were classified as having abnormal vision if they had high-contrast VA of more than 0.1 logarithm of the minimal angle of resolution units or visual field loss. The association of subject age, glioma location, and RNFL thickness with both VA and low-contrast letter acuity scores was evaluated by 1-way analysis of variance and linear regression, using the generalized estimating equation approach to account for within-patient intereye correlations. Eighty-nine eyes of patients with optic pathway gliomas were included, and 41 were classified as having abnormal VA or visual field loss. Reduced RNFL thickness was associated significantly with higher logarithm of the minimal angle of resolution scores for both VA (P < .001) and all low-contrast letter acuity charts (P < .001) when accounting for age and glioma location. Eyes of most children with optic pathway gliomas and decreased RNFL thickness had abnormal VA or visual field loss.

Effect of Cataract and its Removal on Signal Strength and Peripapillary Retinal Nerve Fiber Layer Optical Coherence Tomography Measurements

To assess the effect of cataract on optical coherence tomography (OCT), signal strength (SS), and peripapillary retinal nerve fiber layer (RNFL) thickness measurements. Peripapillary RNFL thickness measurements were obtained by Stratus OCT scans using the Fast RNFL thickness (3.4) acquisition protocol before and after cataract extraction in 45 patients with cataract, including 23 glaucoma patients. Cataracts were graded according to the Lens Opacities Classification System III. The postoperative RNFL thickness and SS were 9.3% (P=0.001) and 24.1% (P<0.001) higher than before surgery, respectively. There was greater postoperative change in RNFL thickness measurements in patients with lower preoperative RNFL measurements (r=-0.63, P<0.001) and SS (r=-0.59, P<0.001). Eyes with preoperative SS more than 6 had no significant difference between precataract and postcataract surgery RNFL thickness (P=0.14). There was no significant difference in RNFL thickness change between eyes with cataract only (10.9±20.8 μm) and those with cataract and glaucoma (7.0±14.7 μm; P=0.81). Cataracts may decrease peripapillary RNFL thickness measurements and the SS on OCT scans. Thinning of the peripapillary RNFL suggestive of glaucomatous progression may be the result of artifact from advancing cataract rather than actual structural changes in the peripapillary RNFL. Peripapillary RNFL thickness measurements should be interpreted with caution in glaucomatous eyes with significant cataract, particularly if the SS is attenuated.

Retinal nerve fiber layer defect patterns in primary angle-closure and open-angle glaucoma: A comparison using optical coherence tomography

To compare the patterns of retinal nerve fiber layer (RNFL) thickness loss in primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG) using optical coherence tomography (OCT). Forty-three participants with PACG and 60 with POAG underwent fast RNFL thickness measurement by OCT. Eyes were classified according to the visual field mean deviation (VF-MD) into mild (>-8 dB), moderate (-8 dB to >-16 dB), and advanced (≤ -16 dB) glaucoma subgroups. The raw RNFL thickness data were compared with data from the Thai normative database. Mean (SD) age was 67.0 (9.6) and 64.1 (11.6) years in the PACG and POAG groups, respectively (P = 0.19). In the mild subgroups, a focal RNFL thickness loss was found in the inferior area in the POAG group, but not in the PACG group. The RNFL defect involved sectors 1, 6, and 7 in the moderately advanced disease subgroups of both PACG and POAG and extended through almost all sectors in the advanced disease subgroups. The deepest RNFL defect, -17.25 μm, was found in sector 6 of the mild POAG subgroup, compared with -8.78 μm in the PACG group (P = 0.04). The number of affected points in each sector in the mild subgroups was greater in the POAG group than in the PACG group. Participants with mild POAG had deeper and more localized RNFL defects than did participants with PACG. The pattern was similar in participants with moderate or advanced disease.

Optical coherence tomography in the evaluation of neurofibromatosis type-1 subjects with optic pathway gliomas

Neurofibromatosis type 1 (NF1) is the most common neurocutaneous disorder, with an approximate incidence of 1 in 3,500. Optic pathway gliomas (OPGs) develop in 15% of individuals with NF1, commonly in childhood. OPGs are difficult to detect via a clinical inspection in children, often requiring magnetic resonance imaging (MRI). Given the significant visual risks associated with OPGs in NF1, there is a need for improved noninvasive techniques to diagnose OPGs in children; therefore, we studied optical coherence tomography (OCT) as a potential tool to assess optic nerve and retinal nerve fiber layer (RNFL) abnormalities. This prospective study was designed to evaluate OCT detection of RNFL loss from optic atrophy attributable to OPGs in a cohort of pediatric patients with NF1. With the use of Stratus OCT, directed testing with the Fast Macular Thickness and Fast RNFL Thickness protocol scans were performed on 9 subjects with NF1 and known OPGs, 6 subjects with NF1 without OPGs, and 15 controls. NF1 subjects with OPGs had thinner RNFLs and macula when compared with age-matched controls and to NF1 subjects without OPGs. After applying the equivalence equation, the average RNFL thickness and macular volume in NF1 subjects without OPGs was equivalent to controls. Our study suggests that OCT can be used to detect RNFL thinning secondary to OPGs in NF1 subjects. This objective tool shows promise as a useful adjunct to routine clinical ophthalmologic evaluation in children with NF1.

Abstract #16: Optical Coherence Tomography As a Clinical Trial Outcome Measure in Multiple Sclerosis: Implications of Treating On-Study Relapses with Intravenous Methylprednisolone

Background Optical coherence tomography (OCT) is potentially useful as an outcome measure for clinical trials of neuroprotective therapies in multiple sclerosis (MS). In large-scale clinical trials, it is common for study participants to receive intravenous methylprednisolone (IVMP) as a treatment for relapses while on study. Other anatomic imaging measures such as brain atrophy are subject to transient changes attributed to the anti-inflammatory and water-shifting effects of IVMP, which necessitates delaying imaging studies within a study relative to IVMP dosing. We studied whether IVMP induces short-term changes in OCT metrics including retinal nerve fiber layer thickness (RNFLT) and macular volume (MV). Methods 20 MS patients who received treatment with IVMP for a relapse other than optic neuritis plus 11 controls (patients with MS without relapse or IVMP treatment) were prospectively recruited. Baseline Stratus OCT Fast RNFLT and Fast Macular Volume protocols were performed immediately prior to the first dose of IVMP and repeated 14 days later in steroid-treated patients. Control patients not receiving IVMP underwent follow-up OCT between 14 and 28 days after the baseline scan. A standard protocol of 1000 mg IVMP daily for 3 days followed by a 12-day oral prednisone taper was utilized in all steroid-treated patients. Patients on intermittent pulse IVMP were excluded. Repeated measures mixed statistical models were used to estimate the effect of treatment with IVMP on RNFLT and MV. Results Data from one eye of a control participant were excluded because unilateral primary retinal pathology invalidated the OCT data. All other data were analyzed, including baseline data from one patient in each group who did not complete follow-up. Mean RNFLT at baseline was 87.9 μm in steroid-treated participants and 81.9 μm in control participants. Mean baseline to follow-up change in RNFLT in steroid-treated patients was 2.80 μm (range −4.76 to 17.79 μm). Based on the mixed effects model, the estimated treatment effect of IVMP on baseline to follow-up RNFLT change was 2.14 μm (95% CI = −1.63 to 5.92; p = 0.25). For MV change, the estimated treatment effect was 0.11 mm 3 (95% CI = −0.05 to 0.28; p = 0.17). Conclusions The observed trends suggest any treatment effect of a single course of IVMP on RNFLT and MV is small, and that altering the timing of OCT following treatment of MS relapses within clinical trials may not be necessary. Additional data are needed to confirm this.

Horizontal Deviation of Retinal Nerve Fiber Layer Peak Thickness With Stratus Optical Coherence Tomography in Glaucoma Patients and Glaucoma Suspects

To evaluate the prevalence of nasal or temporal shifts in retinal nerve fiber layer (RNFL) peak contours with Stratus optical coherence tomography (OCT) and possible associations with demographic or glaucoma-related variables in glaucoma patients and glaucoma suspects, and to emphasize the importance of this finding in clinical practice. This was a retrospective case series of glaucoma patients and glaucoma suspects (1 eye per patient) who underwent a Fast RNFL thickness study with the Stratus OCT. A study was considered to have a clinically significant horizontal deviation if there was greater than 20 degrees shift from the normative database in both superior and inferior peaks. A second cutoff value of 12 degrees was also used to examine smaller deviations. A linear regression model was used to assess correlations of demographic and glaucoma-related variables between eyes with and without significant deviations. Of 400 subjects screened, 273 met the inclusion and exclusion criteria. Thirty-nine eyes (14.3%) had clinically significant horizontal deviation using the 20 degrees cutoff [95% confidence interval (CI), 10%-19%], whereas 122 (44.7%) met the definition with the 12 degrees cutoff (95% CI, 38%-51%). In addition, 121 eyes (44.3%) had a greater than 20 degrees horizontal shift of either the superior or inferior peak (95% CI, 38%-51%). There was no correlation with the demographic or glaucoma-related variables and the horizontal deviation of peak contours. This study suggests that the significant horizontal deviation of peak RNFL contours with the Stratus OCT Fast RNFL is common and emphasizes the need for caution when interpreting the influence of such deviations on clock-hour segment thinning. It is not possible with this technology to distinguish between translational scan circle misalignment (horizontal or vertical) and anatomic variation as the explanation for the finding, and further study with newer technology is needed.

Comparison of optic nerve head topography findings in eyes with non-arteritic anterior ischemic optic neuropathy and eyes with glaucoma

To compare the peripapillary retinal nerve fiber layer (RNFL) thickness in eyes affected by non-arteritic ischemic optic neuropathy (NAION) or glaucoma as determined by optical coherence tomography (OCT). This cross-sectional institutional study included 18 eyes with NAION (at least 6 months since the acute event) and 29 eyes with glaucoma, both having localized visual field (VF) defects confined to one hemifield. Twenty-nine normal subjects served as controls. The fast RNFL thickness protocol (3.4) of the Stratus OCT (Carl Zeiss Meditec, Dublin, CA, USA) was used. The RNFL thickness and inferior maximum/temporal average (Imax/Tavg) and superior maximum/temporal average (Smax/Tavg) data corresponding to the hemifield with and without visual sensitivity loss were compared between NAION and glaucomatous eyes and with corresponding quadrants in normal eyes. The area under the receiver operating characteristic curve (AUC), sensitivities, and specificities were used to determine the OCT parameters that differ most in the two groups. The mean RNFL thickness in the quadrants corresponding to the affected hemifield in the NAION and glaucomatous eyes was not significantly different (P > 0.9), but the values for both were decreased compared to the control eyes (P < 0.0001). The mean RNFL thickness in the quadrant corresponding to the unaffected hemifield was significantly lower in the glaucomatous eyes (73.8 +/- 20.04 micro) than in the NAION eyes (96.6 +/- 23.32 micro, P = 0.023), and in both study groups compared to the controls (117.2 +/- 13.44 micro, P < 0.0001 for glaucomatous vs control eyes, and P < 0.025 for NAION vs control eyes). Smax/Tavg and Imax/Tavg of the quadrant corresponding to the unaffected hemifield had the strongest power to differentiate the two diseases (an AUC of 0.92). Stratus OCT detected significant quantitative differences in RNFL thickness between glaucomatous and NAION eyes, both conditions with hemifield defects. These differences might hold a clue in understanding the processes involved in optic nerve injury.

Korean normative database for time domain optical coherence tomography to detect localized retinal nerve fiber layer defects (preliminary study)

To establish a Korean normative database of retinal nerve fiber layer (RNFL) thickness. Data was collected from 103 healthy volunteers. Total ophthalmologic examinations, including fast RNFL thickness analysis by time domain optical coherence tomography (STRATUS OCT) were performed. The RNFL thickness of 64 glaucoma patients with localized RNFL defects and 48 independent healthy subjects were collected. The RNFL thickness of both the glaucoma patients and the healthy subjects was evaluated using both normative databases. The average RNFL thickness of Koreans was 108.3 +/- 10.3 microm. The sensitivity rates recorded in the Korean normative database with 5% and 1% significance were 0.984 and 0.984, with specificity values of 0.938 and 1.000. By comparison, the sensitivity rates in the conventional normative database with 5% and 1% significance are 0.984 and 0.953, and the specificity values are 1.000 and 1.000. In detecting localized RNFL defects, the Korean database showed higher sensitivity than the conventional database.

Comparison of Retinal Nerve Fiber Layer Thickness in Early Normal-Tension Glaucoma and Early Primary Open-Angle Glaucoma

Purpose: To investigate the comparison of retinal nerve fiber layer (RNFL) thickness parameters measured by optical coherence tomography (Stratus OCT 3000TM) and visual field indices in early normal-tension glaucoma (NTG) and early primary open-angle glaucoma (POAG). Methods: Sixty-one early normal-tension glaucomatous eyes, 21 early primary open-angle glaucomatous eyes and 34 healthy control eyes were enrolled in this cross-sectional study. Each subject received a visual field test (Humphrey C30-2) and the fast RNFL thickness algorithm test by OCT. The correlations between RNFL thickness and visual field indices were analyzed. The sensitivity and specificity for the detection of early glaucoma were determined with the area under the receiver operating characteristics curve (AUROC). Results: All RNFL thickness values except for the temporal quadrant RNFL thickness were significantly decreased in the early NTG and POAG groups (p

Comparison of the peripapillary retinal nerve fiber layer thickness in healthy subjects measured by spectral‐domain Cirrus optical coherence tomography and time‐domain Stratus optical coherence tomography

Abstract Purpose to compare Cirrus Fourier‐domain optical coherence tomography (OCT) with Stratus Time‐domain OCT for measuring the peripapillary retinal nerve fiber layer (RNFL) thickness in healthy subjects. Methods One hundred and thirty two healthy subjects were prospectively and consecutively selected. Only one eye was ramdomly included in the study. All of them underwent three optic disc cube 200x200 scans with the Cirrus HD‐OCT system (Carl Zeiss Meditec, Inc.). The average of the 3 scans was calculated. With the Stratus OCT system (Carl Zeiss Meditec, Inc.) a fast RNFL thickness scan was recorded. The average of RNFL thickness, and RNFL thickness at each quadrant, and each 12 clock‐hours position was evaluated comparing both devices. Reproducibility of RNFL thickness measurements using de Cirrus HD‐OCT was studied, and the variation coefficient (COV) was calculated. Results Mean age was 40.06 ± 13.63 years (ranged from 17 to 72 years). Thirty nine were men (29.5%) and 93 women (70.5%). The average of the peripapillary RNFL thickness was 96.16 µm and 98.27 µm using Cirrus HD‐OCT and Stratus OCT respectively (p=0.001). Statistically differences were found in the temporal quadrant (p=0.026) as well as in several hour sectors. The Cirrus HD‐OCT reproducibility was high, with a mean COV of 4.54% (ranged from 1.64% to 6.37%). Conclusion Mean peripapillary RNFL thickness measured with Cirrus HD‐OCT is slightly lower than with Stratus OCT.

Toxic effect of vigabatrin on retinal nerve fiber layer

Abstract Purpose To investigate whether peripheral and central visual field defects detected among epilepsy patients treated with vigabatrin are associated with reduced peripapillary retinal nerve fiber layer thickness as measured with optic coherence tomography (OCT). Methods Nine epilepsy patients with vigabatrin‐attributed visual field loss (group 1) and seven patients(age and sex matched) with epilepsy treated with other drugs(control group 2) were regularly examined with automated perimetry up to 60 degrees from fixation point (Humphrey Field Analyser). Peripapillary retinal nerve fiber layer thickness (RNFLT) was quantified by optic coherence tomography (OCT) using Fast RNFLT protocol, Stratus OCT (3.0). Five of the patients in group 1 had peripheral visual field defects, (group 1a), four had a central field defect(group 1b). All patients in control group 2 had normal visual field. Results Patients with vigabatrin‐attributed visual field loss had attenuated total RNFLT compared to controls (right eye : mean total RNFLT: group 1: 75.6 µm (SD 12.7); group 2: 103.5 µm (SD 9.7), mean difference 27.9 µm (CI 15.9‐39.9;P &lt; 0.001). The nasal and inferior sectors RNFLT were more attenuated in patients with vigabatrin‐attributed visual field loss compared to controls, while no difference was detected in the temporal RNFLT. Both individuals with peripheral and central visual field losses had attenuated mean total RNFLT compared to controls (P = 0.006 and P= 0.002, respectively). Conclusion Vigabatrin‐attributed visual field defects are associated with reduced RNFLT. Combination of perimetry and OCT can efficiently detect vigabatrin induced retinal nerve fiber damage.

Comparative studies of RNFL thickness measured by OCT with global index of visual fields in patients with ocular hypertension and early open angle glaucoma

To compare the functional changes in visual fields with optical coherence tomography (OCT) findings in patients with ocular hypertension, open angle glaucoma, and suspected glaucoma. In addition, our purpose is to evaluate the correlation of global indices with the structural glaucomatous defect, to assess their statistical importance in all the groups of our study, and to estimate their validity to the clinical practice. One hundred sixty nine eyes (140 patients) were enrolled. The patients were classified in three groups. Group 1 consisted of 54 eyes with ocular hypertension, group 2 of 42 eyes with preperimetric glaucoma, and group 3 of 73 eyes with chronic open angle glaucoma. All of them underwent ophthalmic examination according to a prefixed protocol, OCT exam (Stratus 3000) for retinal nerve fiber layer (RNFL) thickness measurement with fast RNFL thickness protocol and visual fields (VF) examination with Octopus perimeter (G2 program, central 30-2 threshold strategy). Pearson correlation was calculated between RNFL thickness and global index of VF. A moderate correlation between RNFL thickness and indices mean sensitivity (MS), mean defect (MD) and loss variance (LV) of VF (0.547, -0.582, -0.527, respectively; P <0.001) was observed for all patients. Correlations of the ocular hypertension and preperimetric groups are weak. Correlation of RNFL thickness with global indices becomes stronger as the structural alterations become deeper in OCT exam. Correlation of RNFL thickness with the global index of VF, in respective segments around optic disk was also calculated and was found significant in the nasal, inferior, superior, and temporal segments. RNFL average thickness is not a reliable index for early diagnosis of glaucoma and for the follow-up of patients with ocular hypertension. Segmental RNFL thickness seems to be a more reliable index. Deep structural alterations with OCT examination constitute an important indication of early functional changes, even if they are not still detected with achromatic perimetry. The MD index of VF seems to be more sensitive for the follow-up of patients with ocular hypertension.

Early Stage Ethambutol Optic Neuropathy: Retinal Nerve Fiber Layer and Optical Coherence Tomography

To evaluate retinal nerve fiber layer (RNFL) thickness with optical coherence tomography (OCT) in early stage ethambutol optic neuropathy. The RNFL thickness of 20 eyes of 10 patients who developed optic neuropathy after taking ethambutol and visited within 6 months after onset were analyzed and compared with those of 54 eyes of 29 healthy age-matched controls. The mean age was 67.40+/-10.25 years for the patients with toxic optic neuropathy and 66.78+/-10.60 for the control group (p=0.948). A full ophthalmologic examination including RNFL evaluation with fast RNFL thickness (3.4) scanning using a Stratus OCT (Carl Zeiss Meditec, Dublin, CA) was performed. RNFL thicknesses associated with early ethambutol optic neuropathy were as follows: temporal 75.35+/-15.77 microm, superior 124.05+/-24.62 microm, nasal 75.15+/-24.23 microm, inferior 127.60+/-22.91 mum, and the average was 100.83+/-16.56 microm. There was no significant difference between the RNFL thickness of the patients with the early stage of ethambutol optic neuropathy and those of the control group. The thickness of RNFL was greater in the temporal quadrant than the nasal quadrant, although not statistically significant. RNFL thickness associated with ethambutol optic neuropathy during the early stages was no different from the controls. Although not statistically significant, the relative thickening of temporal RNFL in our patients might represent a mild swelling of the papillomacular bundle.