Peripapillary Retinal Nerve Fiber Layer Thickness Measurements Research Articles

Segmentation Errors and Off-Center Artifacts in SS-OCT: Insight from a Population-Based Imaging Study

Purpose To evaluate the frequency and associated factors of artifacts in swept-source optical coherence tomography (SS-OCT) imaging. Methods This was a population-based cross-sectional study. Individuals aged 35 years or older, residing in the Yuexiu district of Guangzhou, China, were recruited by random cluster sampling. Nearly half of the participants were randomly selected for SS-OCT imaging centered on the optic nerve head. Six types of artifacts in the peripapillary choroidal layer and retinal nerve fiber layer (RNFL) were graded and identified. Univariate and multivariate logistic regression analyses were used to investigate the association between the presence of artifacts and clinical characteristics. Results Out of the 616 eligible individuals who underwent SS-OCT imaging, 18.3% and 13.6% of subjects exhibited at least one artifact in peripapillary RNFL (pRNFL) and peripapillary choroidal thickness (pCT) measurements, respectively, with posterior segmentation error and off-center artifact ranked as the most common artifacts. The presence of artifacts was significantly associated with age (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.01–1.06; p = .003), refractive error (OR, 0.80; 95% CI, 0.71–0.89; p < .001), and signal strength (OR, 0.95; 95% CI, 0.90–0.997; p = .039) in pRNFL thickness measurement. Similarly, the presence of artifacts in pCT measurement was significantly associated with age (OR, 1.05; 95% CI, 1.03–1.08; p < .001), and refractive error (OR, 0.76; 95% CI, 0.68–0.86; p < .001). Conclusion Nearly one-fifth of the eyes were noted with at least one artifact in the population-scale SS-OCT study. Age was a risk factor for the presence of artifacts and should be considered in clinical settings.

New Findings in Early-Stage Keratoconus: Lamina Cribrosa Curvature, Retinal Nerve Fiber Layer Thickness, and Vascular Perfusion

PurposeOur aim was to investigate the involvement of posterior pole structures in eyes affected by keratoconus (KC). Optical coherence tomography (OCT) and OCT angiography (OCTA) were used to determine the status of lamina cribrosa (LC), peripapillary retinal nerve fiber layer (RNFL), macular and peripapillary microvasculature. DesignObservational, cross-sectional, case-control analysis. MethodsSingle-center investigation involving patients with KC and healthy control subjects. Enrolled subjects underwent anterior segment OCT combined with Placido-disk topography, macular and optic nerve head swept-source OCT and swept-source OCTA scans, and 3D wide glaucoma module for peripapillary RNFL thickness measurement. The LC curvature index was used to express the degree of LC posterior bowing. We calculated the vessel density and vessel length density at the macular superficial capillary plexus, deep capillary plexus, choriocapillaris, and nerve radial peripapillary capillary plexus. ResultsOverall, 32 eyes with KC and an equal number of age- and axial length–matched control eyes were included in the analysis. Almost all (97%) of eyes with KC were classified as early stage. KC displayed a reduction in peripapillary RNFL thickness (104.8 ± 11.9 µm vs 110.7 ± 10.5 µm; P = .039) and nerve radial peripapillary capillary plexus vessel density (46.31% ± 3% vs 43.82% ± 4%; P = .006) when compared with control subjects; these differences were more evident in the temporal sector and were associated with a higher LC curvature index (9.9% ± 2.6% vs 8.48% ± 1.7%; P = .012). Mean macular superficial capillary plexus vessel density was 3 percentage points lower in eyes with KC than in healthy controls (P < .001). ConclusionEarly-stage KC may be characterized by a posterior bowing of the LC along with a subtle peripapillary RNFL thinning and vascular impairment. These findings support the hypothesis that KC may be a corneal manifestation of a more generalized “eye collagen disease.”

Study of peripapillary retinal nerve fiber layer thickness in patients of type 2 diabetes mellitus and its correlation with glycemic control

Context: The retina of diabetic patients undergoes neurodegenerative changes, in addition to the vascular changes. Aims: The aim of this study is to evaluate the peripapillary retinal nerve fiber layer (RNFL) thickness in type 2 diabetes mellitus (DM) patients compared to healthy controls, using optical coherence tomography (OCT) and to correlate it with glycemic control. Settings and Design: Prospective study. Subjects and Methods: A total of 90 patients were enrolled in the study. The study group included 120 eyes of 60 type 2 DM patients. Sixty eyes of 30 healthy participants served as the control group. All patients underwent an OCT scan for peripapillary RNFL thickness measurement. Metabolic control of DM was assessed using glycosylated hemoglobin (HbA1c). Statistical Analysis Used: Independent sample t-test was used for normally distributed variables. Pearson's correlation analysis was used to assess the correlation between HbA1c and RNFL thickness. Results: Right eye RNFL thickness was thinner in diabetic patients than controls, with a statistically significant P value (P = 0.002) in the superior quadrant and inferior quadrant (P = 0.019). The average, superior, and inferior RNFL thickness in the left eye was significantly thinner in diabetic patients as compared to controls (P

Dose-Response Relationship between Intravitreal Injections and Retinal Nerve Fiber Layer Thinning in Age-Related Macular Degeneration

To determine if multiple intravitreal injections of vascular endothelial growth factor (VEGF) inhibitors for unilateral exudative age-related macular degeneration (eAMD) are associated with thinning of the retinal nerve fiber layer (RNFL), we compared RNFL thickness measurements from the injected eye with that of the fellow eye with nonexudative age-related macular degeneration (neAMD). Retrospective, cross-sectional study. Patients undergoing anti-VEGF therapy for unilateral eAMD. Patients receiving anti-VEGF therapy secondary to eAMD in 1 eye with neAMD in their fellow eye were identified. Patients with a known diagnosis of glaucoma were excluded. Spectral domain OCT measurements of the peripapillary RNFL thickness from both eyes were performed and compared. The differences in the RNFL thickness measurements between eyes were correlated with the number of injections and the duration of therapy. Correlation between the number of anti-VEGF injections and peripapillary RNFL thinning. A total of 108 eyes of 54 patients were evaluated in this study. The average peripapillary RNFL thickness measurements of the injected eye and fellow eye were 87.3 ± 9.6 μm and 89.0 ± 7.5 μm, respectively (P= 0.055). The RNFL thickness difference (fellow eye minus injected eye) was significantly correlated with the number of injections (r= 0.40, P= 0.002) and months of injections (r= 0.38, P= 0.005). The relationship between the difference in the RNFL thickness and the number of injections had a nonlinear dose-response relationship that became apparent after approximately 30 injections and 50 months of injections. The difference in RNFL thickness measurements between injected eyes and uninjected fellow eyes was largely within the reported normal limits for interocular differences between healthy eyes. Nevertheless, there was a dose-response relationship between RNFL thinning and number of injections among patients receiving a greater number of injections, suggesting that anti-VEGF injections may have a modest effect on the RNFL thickness after several years of therapy in eyes requiring more anti-VEGF injections; however, we cannot exclude that the RNFL thinning may be secondary to active age-related macular degeneration (AMD) disease progression in both eyes.

Hyperopic peripapillary retinal nerve fiber layer thickness and foveal thickness using optical coherence tomography

Purpose Studying the peripapillary retinal nerve fiber layer (RNFL) thickness and foveal thickness in hyperopia using optical coherence tomography. Background Significant hyperopia is defined to be any degree of hyperopia sufficient to cause symptoms requiring remediation. Peripapillary RNFL thickness was approved to be conversely correlated with axial length (AL) and the spherical equivalent in hyperopic populations. Optical coherence tomography is a modern noncontact and noninvasive imaging technique designed to produce high-resolution images and accurate measurements of the different retinal components. Patients and methods The presented study included ninety eyes: 45 of them were simple hyperopic eyes, and the other 45 eyes were emmetropic. The emmetropic eyes were age and sex matched to the case group. The participants were included in the study after obtaining informed consent and a detailed history. Ophthalmological examination including visual acuity assessment, cycloplegic refraction, best-corrected visual acuity, cover–uncover test and extraocular muscle movement examination, anterior segment examination, intraocular pressure measurement, fundus examination, AL measurement, and peripapillary RNFL thickness and foveal thickness measurements (all methods of assessment are mentioned in detail in the patients and methods section) was carried out. Results There was no statistically significant difference between the hyperopic and the emmetropic groups with regard to age and sex. There was a statistically significant increase in the thickness of the RNFL in the hyperopic group that was more than that of the emmetropic group, and there was a statistically significant increase in the thickness of the superior, inferior, and nasal quadrants in the hyperopic group more than that of the emmetropic group. There was no statistically significant difference in the temporal quadrant between both groups. Conclusion The AL is statistically significantly short, and the mean foveal thickness is statistically significantly high in the hyperopic eyes. The RNFL thickness is statistically significantly thick, and the superior, inferior, and nasal quadrants were thicker in the hyperopic eyes than in the emmetropic ones.

The Relationship Between Optic Nerve Cup-to-Disc Ratio and Retinal Nerve Fiber Layer Thickness in Suspected Pediatric Glaucoma.

To evaluate the relationship between optic nerve cup-to-disc ratio and peripapillary retinal nerve fiber layer (RNFL) thickness in suspected pediatric glaucoma with large cup-to-disc ratios. This was a retrospective study undertaken at a single academic institution. Eighty-six eyes of 43 patients who presented with large (≥ 0.5) cup-to-disc ratios in both eyes and without elevated intraocular pressure were evaluated using spectral-domain optical coherence tomography. Global and sectoral peripapillary RNFL thickness measurements, Bruch's membrane opening size, refractive error in spherical equivalents, and intraocular pressure levels were recorded for all patients. Cup-to-disc ratios were manually derived using digital fundus images (D-cup-to-disc ratio). Parameters were compared between gender or race by t tests or analysis of variance. The differences in the relationship among the clinical parameters between two eyes were assessed using generalized estimation equation modeling followed by Pearson's correlation analysis. Forty-three patients (25 boys and 18 girls) with a mean age of 9.3 ± 2.7 years (range: 5 to 15 years) were included. The mean global peripapillary RNFL thickness and the D-cup-to-disc ratio of study eyes were 99.0 ± 9.2 µm and 0.66 ± 0.03, respectively. The peripapillary RNFL thickness was found to be correlated with refractive error (r = 0.404; P = .008) and Bruch's membrane opening size (r = 0.410; P = .008) but not with cup-to-disc ratios (r = 0.029; P = .858) or patient age (r = -0.044; P = .797). In patients with suspected pediatric glaucoma who present with large cup-to-disc ratios, RNFL thickness does not correlate with the degree of optic nerve cupping. Myopic refractive errors and Bruch's membrane opening size need to be taken into consideration to prevent misinterpretation of peripapillary RNFL measurements. [J Pediatr Ophthalmol Strabismus. 2020;57(2):90-96.].

Reliability of Handheld Optical Coherence Tomography in Children Younger Than Three Years of Age Undergoing Vigabatrin Treatment for Childhood Epilepsy.

PurposeVigabatrin-associated retinal toxicity manifests as reduction in the clinical electroretinogram and retinal nerve fiber layer (RNFL) thinning. This observational investigation of RNFL thickness in young vigabatrin-treated children was to identify intravisit and intervisit reliabilities of peripapillary RNFL thickness measurements performed with Envisu (optical coherence tomography) OCT. Secondarily, a longitudinal assessment investigated the presence and extent of RNFL thinning.MethodsWe measured the handheld OCT in sedated children to evaluate the RNFL thickness using segmentation software. Intraclass correlation coefficient (ICC) statistics identified intravisit and intervisit reliabilities for RNFL thickness.ResultsTwenty-nine children (10.1 ± 6.0 months old) underwent handheld optical coherence tomography (OCT). Fourteen of these completed follow-up assessments. Intravisit reliability was good for the right eye (ICCs = 0.82−0.98) and the left eye (ICCs = 0.75−0.89) for each of the 4 retinal quadrants. Inter-visit ICCs for each of the 4 retinal quadrants were good (ICC = 0.82−0.98). There was no consistent change in RNFL thickness longitudinally.ConclusionsIn this pediatric cohort, RNFL thickness measures using handheld OCT provided good reliability within a single visit and between consecutive visits supporting its use as an adjunctive tool in the clinical setting. Further long-term follow-up is required to understand RNFL thickness changes in this specific population and its association with vigabatrin toxicity.Translational RelevanceThe findings of good reliability and clinical feasibility would provide an opportunity for the handheld OCT to monitor reliably for vigabatrin-associated retinal toxicity in children who often show noncompliance to traditional testing approaches.

CORRELATIONS between Functional and Structural Tests Measured by Spectral Domain Optical Coherence Tomography in Severe Glaucoma

ABSTRACTPurpose: To evaluate the relationship between visual acuity, visual field and spectral domain optical coherence tomography (OCT) parameters, including retinal nerve fiber layer (RNFL), ganglion cell-internal plexiform layer (GC-IPL) thicknesses, and optic nerve head parameters in patients with severe glaucoma.Material and Methods: Patients with the diagnosis of severe glaucoma were recruited from the data gathered at our glaucoma department. A detailed ophthalmic examination was performed using the Standard Automated Perimetry (the 30–2 SITA standard program was used for VF testing). Cirrus EDI-OCT was used for peripapillary RNFL and GC-IPL thickness measurements. Optic nerve head parameters, including mean cup-to-disc (c/d) ratio, rim area, vertical c/d ratio, cup volume, were also measured by spectral domain OCT. Correlations between these structural parameters and functional parameters (visual acuity, VF parameters) were investigated.Results: Forty-one eyes of 34 patients with severe glaucoma were enrolled in this study. Correlations between BCVA and mean GC-IPL thickness (p = .03), superior GC-IPL thickness (p = .03), inferonasal GC-IPL thickness (p = .01), superonasal GC-IPL thickness (p = .01), superotemporal GC-IPL thickness (p = .04), and rim area (p = .00) were found to be positive statistically significant. There was also a positive statistically significant correlation between MD and inferotemporal GC-IPL thickness (p = .03). Negative statistically significant correlations were found between BCVA and mean c/d ratio (p = .00), vertical c/d ratio (p = .02) and cup volume (p = .00).Discussion: Mean, superior, inferonasal, superonasal, and superotemporal GC-IPL thicknesses and mean c/d ratio, vertical c/d ratio and cup volume were found to be correlated with BCVA in patients with severe glaucoma.

Retinal Nerve Fiber Layer Thickness in Various Retinal Diseases.

Peripapillary retinal nerve fiber layer (RNFL) thickness measurements may be influenced by the range and severity of lesions that are observed distinctively in each retinal disease. We investigated the effects of various macular (central serous chorioretinopathy, macular hole, epiretinal membrane, wet age-related macular degeneration) and retinal vascular (branch retinal vein occlusion, central retinal vein occlusion, diabetic macular edema) diseases on peripapillary RNFL thickness measurements using spectral-domain optical coherence tomography. Six hundred thirty-one eyes from 464 patients with various retinal diseases and 167 controls of similar age were included in this retrospective study. Using spectral-domain optical coherence tomography, we measured the thickness of the macula and the RNFL in both various retinal disease eyes and normal control eyes. Four sectorial and average RNFL thicknesses were compared between each disease and age-matched control eyes. The macular thicknesses were also compared. In the macular disease group, superior (P = .033) and temporal (P = .024) quadrant RNFL thicknesses of central serous chorioretinopathy and temporal (P < .001) quadrant RNFL thicknesses of epiretinal membrane were greater than the age-matched control eyes. No RNFL measurements in macular hole or wet age-related macular degeneration differed significantly from the controls. In the retinal vascular disease group, all sectorial and average RNFL thicknesses of diabetic macular edema and central retinal vein occlusion were greater than those of the controls (all P < .05). In branch retinal vein occlusion, superior (P = .012) and temporal (P < .001) quadrant RNFL thicknesses were greater than those of the controls. Peripapillary RNFL thickness measurements may be influenced by the range and severity of lesions that are observed distinctively in each retinal disease. It also appeared that macular disease had a local effect on RNFL thickness, whereas retinal vascular disease had a diffuse effect on RNFL thickness.

Peripapillary Retinal Nerve Fiber Layer Thicknesses Did Not Change in Long-term Hydroxychloroquine Users.

PurposeTo evaluate changes in the peripapillary retinal nerve fiber layer (RNFL) thicknesses using spectral-domain optical coherence tomography (SD-OCT) in hydroxychloroquine (HCQ) users.MethodsThe medical records of HCQ users were retrospectively reviewed. In these HCQ users, an automated perimetry, fundus autofluorescence photography, and SD-OCT with peripapillary RNFL thickness measurements were performed. The peripapillary RNFL thicknesses were compared between the HCQ users and the control groups. The relationships between the RNFL thicknesses and the duration or cumulative dosage of HCQ use were analyzed.ResultsThis study included 77 HCQ users and 20 normal controls. The mean duration of HCQ usage was 63.6 ± 38.4 months, and the cumulative dose of HCQ was 528.1 ± 3.44 g. Six patients developed HCQ retinopathy. Global and six sectoral RNFL thicknesses of the HCQ users did not significantly decrease compared to those of the normal controls. No significant correlation was found between the RNFL thickness and the duration of use or cumulative dose. The eyes of those with HCQ retinopathy had temporal peripapillary RNFL thicknesses significantly greater than that of normal controls.ConclusionsThe peripapillary RNFL thicknesses did not change in the HCQ users and did not correlate with the duration of HCQ use or cumulative doses of HCQ. RNFL thickness is not a useful biomarker for the early detection of HCQ retinal toxicity.

Diagnostic Capability of Peripapillary Three-dimensional Retinal Nerve Fiber Layer Volume for Glaucoma Using Optical Coherence Tomography Volume Scans

To determine the diagnostic capability of peripapillary 3-dimensional (3D) retinal nerve fiber layer (RNFL) volume measurements from spectral-domain optical coherence tomography (OCT) volume scans for open-angle glaucoma (OAG). Assessment of diagnostic accuracy. Setting: Academic clinical setting. Total of 180 patients (113 OAG and 67 normal subjects). One eye per subject was included. Peripapillary 3D RNFL volumes were calculated for global, quadrant, and sector regions, using 4 different-size annuli. Peripapillary 2D RNFL thickness circle scans were also obtained. Area under the receiver operating characteristic curve (AUROC) values, sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios. Among all 2D and 3D RNFL parameters, best diagnostic capability was associated with inferior quadrant 3D RNFL volume of the smallest annulus (AUROC value 0.977). Otherwise, global 3D RNFL volume AUROC values were comparable to global 2D RNFL thickness AUROC values for all 4 annulus sizes (P values: .0593 to .6866). When comparing the 4 annulus sizes for global RNFL volume, the smallest annulus had the best AUROC values (P values: .0317 to .0380). The smallest-size annulus may have the best diagnostic potential, partly owing to having no areas excluded for being larger than the 6×6mm2 scanned region. Peripapillary 3D RNFL volume showed excellent diagnostic performance for detecting glaucoma. Peripapillary 3D RNFL volume parameters have the same or better diagnostic capability compared to peripapillary 2D RNFL thickness measurements, although differences were not statistically significant.

Effects of Diabetic Macular Edema on Repeatability of Retinal Nerve Fiber Layer Thickness Measurements at the Macular and Peripapillary Area Using Swept-Source Optical Coherence Tomography

ABSTRACTPurpose: To investigate the repeatability of macular and peripapillary retinal nerve fiber layer (RNFL) thickness measurements made using swept-source optical coherence tomography (SS-OCT) and automated segmentation. Measurements were made in non-diabetic controls and in patients with diabetic retinopathy (DR) with or without diabetic macular edema (DME).Materials and Methods: A total of 131 eyes of 131 participants were included. Fifty-one eyes with DR had no DME (DME[–]), 45 eyes with DR had DME (DME[+]), and 35 eyes were healthy. Measurements of RNFL and full retinal thickness were simultaneously obtained with SS-OCT in the peripapillary area and in the nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields using the wide three-dimensional mode. All measurements were made twice on the same day by a single examiner to test intra-observer repeatability. Intraclass correlation coefficients (ICCs) and coefficients of repeatability were examined to evaluate repeatability.Results: Average macular and temporal peripapillary RNFL thickness values were greater in the DME[+] group (36.4 ± 13.2 and 83.8 ± 19.4 µm, respectively) than in the control (27.4 ± 3.5 and 73.5 ± 11.4 µm, respectively) and DME[–] (27.9 ± 3.4 µm and 70.3 ± 11.3 µm, respectively) groups (both P < 0.001). The ICCs of average macular (control: 0.982, DME[–]: 0.913, and DME[+]: 0.970) and peripapillary (control: 0.972, DME[–]: 0.973, and DME[+]: 0.958) RNFL thickness measurements indicated good repeatability in all three study groups.Conclusions: Although the ICCs of average RNFL thickness measurements were relatively lower in eyes with DR than in healthy controls, the intra-observer repeatability of SS-OCT RNFL and full retinal thickness measurements is sufficiently reliable for them to be clinically useful.

Evaluation of Retinal Nerve Fiber Layer and Ganglion Cell Complex Thickness in Unilateral Exfoliation Syndrome Using Optical Coherence Tomography

To evaluate retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness by using optical coherence tomography in unilateral exfoliation syndrome (XFS) and to assess whether exfoliation itself is an independent risk factor for glaucomatous optic nerve damage. Thirty exfoliative eyes of unilateral XFS cases, 30 fellow eyes of unilateral exfoliation, and 30 eyes of healthy subjects were enrolled the study. Peripapillary RNFL and macular GCC thickness measurements by Cirrus HD OCT (Carl Zeiss Meditec, Dublin, CA) were performed on all subjects. RNFL thickness in superior quadrant was significantly different between groups (P=0.025) and it was thinner in XFS than healthy subjects (P=0.020). All GCC parameters except GCC thickness in inferior quadrant were significantly different between groups (P=0.110 for inferior quadrant, P<0.046 for other GCC parameters). GCC were thinner in XFS than healthy subjects except inferior and inferonasal quadrants (P=0.091, 0.051 for inferior and inferonasal quadrants, respectively, P<0.039 for other GCC parameters). Minimum GCC thickness, GCC thicknesses in superior, and inferonasal quadrants were significantly thinner in fellow eyes than healthy subjects (P=0.011, 0.013, 0.047, respectively). XFS is related with thinner RNFL and GCC even in normal intraocular pressure values, similar optic disc parameters and visual field results. XFS may be an independent risk factor for glaucomatous optic nerve damage. So, further studies are needed to evaluate whether exfoliation itself is an independent risk factor for optic nerve damage.

Utility of optical coherence tomography in the evaluation of monocular visual loss related to retinal ischemia

We report four patients with monocular visual loss for whom optical coherence tomography (OCT) was helpful in distinguishing the sequelae of retinal artery occlusion from those of primary optic neuropathy. Determinations of the peripapillary retinal nerve fiber layer (RNFL) thickness as well as macular retinal layer thicknesses and architecture were used. The major findings in our patients show that changes in the inner retinal layers (including ganglion cell and inner plexiform layer) with disruption of normal macular architecture supports a diagnosis of retinal artery occlusion. Our results support the use of OCT imaging for patients with monocular visual loss of uncertain etiology; macular imaging as well as peripapillary RNFL thickness measurement can be helpful in differentiating primary retinal disease or ischemia from primary disorders of the optic nerve.

Lack of Correlation Between Diabetic Macular Edema and Thickness of the Peripapillary Retinal Nerve Fibre Layer.

Introduction:We compared the thickness of the peripapillary retinal nerve fiber layer (RNFL) in patients with diabetic macular edema (DME) and/against the thickness in the normal population.Methods:This cross-sectional study compared the RNFL thickness in patients with DME (DME group) using optical coherence tomography (OCT) to a comparable group of healthy (nondiabetic) patients (control group). Measurements were performed in different/the four peripapillary quadrants and in the macula region for the fovea, parafoveal, and perifoveal areas. The mean RNFL thickness was compared between both groups.Results:There were fifty eyes of fifty nonglaucomatous diabetic patients with DME (29 with nonproliferative diabetic retinopathy [PDR] and 21 with PDR), and fifty eyes in the control group. The macular regions were significantly thicker in the DME group compared to the control group. The central foveal thickness was 149 μ thicker in eyes with DME compared to the control group (P < 0.001). The difference in total RNFL thickness between groups was not significant (4.4 μ [95% confidence interval: −3.1 to +12]). The between-group differences in peripapillary RNFL thickness by age group, glycemic control, history of intravitreal treatments, and refractive errors were not statistically significant (P > 0.05, all comparisons).Conclusion:Peripapillary RNFL thickness measurements were not significantly influenced by DME. Hence, OCT parameters could be used to monitor/early detect glaucomatous eyes even in the presence of DME.

Interocular retinal nerve fiber layer thickness difference in normal adults.

PurposeTo determine the interocular retinal nerve fiber layer (RNFL) thickness difference of normal subjects.MethodsBoth eyes of 230 normal adults received peripapillary RNFL thickness measurements using OCT. The effect of ocular cyclotorsion on the RNFL thickness profile was mathematically corrected. The fractional and absolute interocular RNFL thickness differences at 256 points of peripapillary area were calculated. We divided the subjects into 3 groups according to the locations of superior and inferior peak thickness, respectively, and compared the interocular RNFL thickness differences between the subgroups.ResultsThe fractional interocular RNFL thickness difference exhibited smaller regional variations than the absolute interocular difference. The means of fractional interocular differences were 0.100 ± 0.077 in the temporal half area and 0.146 ± 0.105 in the nasal half area, and the tolerance limits for the 95th and 99th distributions were about 0.246 and 0.344 in the temporal half area and 0.293 and 0.408 in the nasal half area, respectively. The fractional interocular differences of subgroups classified by the locations of superior and inferior peak RNFL thickness showed difference at smaller areas than the absolute interocular differences (19 and 8 points versus 49 and 23 points, respectively).ConclusionGlaucoma can be strongly suspected, if interocular fractional RNFL thickness difference is over 25% at 5 consecutive points or over 35% at 3 consecutive points in the temporal half area. The fractional interocular comparison is a better diagnostic approach because the fractional interocular RNFL thickness difference is less influenced by the locations of peak RNFL thickness.

Thickness in Ganglion Cell-Inner Plexiform Layer on Spectral-Domain Optical Coherence Tomography after Cataract Surgery

Purpose: To assess changes in ganglion cell-inner plexiform layer (GCIPL) thickness after cataract surgery using spectral-domain optical coherence tomography (OCT). Methods: Forty-three eyes of 33 patients, who underwent cataract surgery were imaged with spectral-domain OCT before and after surgery to measure peripapillary retinal nerve fiber layer (RNFL) and GCIPL thickness, signal strength (SS), quadrant, 12 clock-hour RNFL thickness and sectoral GCIPL thickness. Results: The postoperative SS, RNFL and GCIPL thickness were higher than before surgery (p < 0.05). Multivariate analysis showed that endothelial cell count and preoperative SS were significantly correlated with SS changes in RNFL parameters and preoperative SS was significantly correlated with SS changes in GCIPL parameters. Univariate analysis indicated that age was significantly correlated with RNFL thickness changes in RNFL parameters and no factor was correlated with GCIPL thickness in GCIPL parameters (p < 0.05). Conclusions: Cataracts may decrease peripapillary RNFL and GCIPL thickness measurements and SS on OCT scans. Peripapillary RNFL and GCIPL thickness measurements should be interpreted with caution in eyes with significant cataracts. J Korean Ophthalmol Soc 2015;56(11):1767-1776

Analysis of the Retinal Nerve Fiber Layer in Retinitis Pigmentosa Using Optic Coherence Tomography.

Aim. To evaluate the peripapillary retinal nerve fiber layer (RNFL) changes in retinitis pigmentosa (RP) patients using spectral domain optic coherence tomography (Sd-OCT). Methods. We retrospectively examined medical records of forty-four eyes of twenty-two RP patients. The results were also compared with those of previously reported forty-four eyes of twenty-two normal subjects (controls). Records of average and four quadrants peripapillary RNFL thickness measurements using Sd-OCT were assessed. Results. In RP patients the mean RNFL thickness was 97.57 ± 3.21 μm. The RNFL in the superior, temporal, nasal, and inferior quadrants was 119.18 ± 4.47 μm, 84.68 ± 2.31 μm, 75.09 ± 3.34 μm, and 113.88 ± 4.25 μm, respectively. While the thinning of RNFL was predominantly observed in the inferior quadrant, the thickening was mostly noted in temporal quadrant. The differences between mean, superior, and nasal quadrant RNFL thicknesses were not statistically significant when compared with control group. The RP patients had thinner inferior quadrant and thicker temporal quadrant than control group (p < 0.05). Conclusion. Sd-OCT is highly sensitive and effective instrument to detect RNFL changes in RP patients. RNFL measurements can provide information about the progression of retinitis pigmentosa and may provide prognostic indices for future treatment modalities.

Diagnostic Capability of Peripapillary Retinal Thickness in Glaucoma Using 3D Volume Scans

To determine the diagnostic capability of spectral-domain optical coherence tomography (SD OCT) peripapillary retinal thickness (RT) measurements from 3-dimensional (3D) volume scans for primary open-angle glaucoma (POAG). Cross-sectional study. setting: Institutional. study population: 156 patients (89 POAG and 67 normal subjects). observation procedures: One eye of each subject was included. SD OCT peripapillary RT values from 3D volume scans were calculated for 4 quadrants of 3 different sized annuli. Peripapillary retinal nerve fiber layer (RNFL) thickness values were also determined. main outcome measures: Area under the receiver operating characteristic curve (AUROC) values, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. The top 5 RT AUROCs for all glaucoma patients and for a subset of early glaucoma patients were for the inferior quadrant of outer circumpapillary annulus of circular grid (OCA) 1 (0.959, 0.939), inferior quadrant of OCA2 (0.945, 0.921), superior quadrant of OCA1 (0.890, 0.811), inferior quadrant of OCA3 (0.887, 0.854), and superior quadrant of OCA2 (0.879, 0.807). Smaller RT annuli OCA1 and OCA2 consistently showed better diagnostic performance than the larger RT annulus OCA3. For both RNFL and RT measurements, best AUROC values were found for inferior RT OCA1 and OCA2, followed by inferior and overall RNFL thickness. Peripapillary RT measurements from 3D volume scans showed excellent diagnostic performance for detecting both glaucoma and early glaucoma patients. Peripapillary RT values have the same or better diagnostic capability compared to peripapillary RNFL thickness measurements, while also having fewer algorithm errors.

Diagnostic Ability of Retinal Nerve Fiber Layer Imaging by Swept-Source Optical Coherence Tomography in Glaucoma

To evaluate the diagnostic accuracies of swept-source optical coherence tomography (OCT) wide-angle and peripapillary retinal nerve fiber layer (RNFL) thickness measurements for glaucoma detection. Cross-sectional case-control study. In this study we enrolled 144 glaucomatous eyes of 106 subjects and 66 eyes of 42 healthy subjects from the Diagnostic Innovations in Glaucoma Study. Glaucoma was defined by the presence of repeatable abnormal standard automated perimetry results and/or progressive glaucomatous optic disc change on masked grading of stereophotographs. Wide-angle and peripapillary RNFL thicknesses were assessed using swept-source OCT. Peripapillary RNFL thickness was also evaluated using spectral-domain OCT. Areas under the receiver operating characteristic (ROC) curves were calculated to evaluate the ability of the different swept-source OCT and spectral-domain OCT parameters to discriminate between glaucomatous and healthy eyes. Mean (± standard deviation) average spectral-domain OCT wide-angle RNFL thicknesses were 50.5 ± 5.8 μm and 35.0 ± 9.6 μm in healthy and glaucomatous eyes, respectively (P < 0.001). Corresponding values for swept-source OCT peripapillary RNFL thicknesses were 103.5 ± 12.3 μm and 72.9 ± 16.5 μm, respectively (P < 0.001). Areas under the ROC curves of swept-source OCT wide-angle and peripapillary RNFL thickness were 0.88 and 0.89, respectively. Swept-source OCT performed similar to average peripapillary RNFL thickness obtained by spectral-domain OCT (area under the ROC curve of 0.90). Swept-source OCT wide-angle and peripapillary RNFL thickness measurements performed well for detecting glaucomatous damage. The diagnostic accuracies of the swept-source OCT and spectral-domain OCT RNFL imaging protocols evaluated in this study were similar.