Macular ganglion cell imaging study: interocular symmetry of ganglion cell-inner plexiform layer thickness in normal healthy eyes

Comparison of Patterns of Structural Progression in Primary Open Angle Glaucoma and Pseudoexfoliation Glaucoma

PRCIS

Primary open angle glaucoma and pseudoexfoliation glaucoma showed different progression patterns of the retinal nerve fiber layer and ganglion cell-inner plexiform layer thinning in OCT-guided progression analysis.

PURPOSE

To compare the patterns of progression of retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thinning by guided progression analysis (GPA) of optical coherence tomography (OCT) in primary open angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXG).

MATERIALS AND METHODS

The progression of RNFL and GCIPL thinning was assessed by the GPA of Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA). By overlaying the acquired images of the RNFL and GCIPL thickness-change maps, the topographic patterns of progressive RNFL and GCIPL thinning were evaluated. The rates of progression of RNFL and GCIPL thinning were analyzed and compared between patients with POAG and those with PXG.

RESULTS

Of the 248 eyes of 248 patients with POAG (175 eyes of 175 patients) or PXG (73 eyes of 73 patients) enrolled, 156 POAG eyes and 48 PXG eyes were included. Progressive RNFL thinning was significantly more common in PXG than in POAG ( P =0.005). According to the RNFL progression-frequency maps, progression appeared mainly in the superotemporal and inferotemporal areas in POAG, whereas it had invaded more into the temporal area in PXG. According to the GCIPL maps, progression was most common in the inferotemporal area in both POAG and PXG. The average progression rate of GCIPL thinning was faster in PXG than in POAG ( P =0.013), and when analyzed in 2 halves (superior/inferior), the progression rate of the inferior half was faster in PXG than in POAG ( P =0.011).

CONCLUSIONS

OCT GPA showed progression patterns of RNFL and GCIPL thinning in POAG and PXG. Understanding the specific patterns of progressive RNFL and GCIPL thinning according to glaucoma type may prove helpful to glaucoma-patient treatment and monitoring.

Interocular Symmetry in Retinal Nerve Fiber Layer Thickness in Children: The Hong Kong Children Eye Study

INTRODUCTION

The aim of this work is to determine the interocular differences in peripapillary retinal nerve fiber layer (p-RNFL) thickness and its associations among school children in Hong Kong.

METHODS

We conducted a population-based study including 4034 children aged 6-8 years from the Hong Kong Children Eye Study (HKCES). All participants received comprehensive ocular examinations where p-RNFL thickness was measured using spectral-domain optical coherence tomography (SD-OCT). The degree of symmetry between both eyes was analyzed and represented by intraclass correlation coefficient (ICC) values. Multivariable linear regression analysis was used to investigate the associations between ocular and systemic factors with p-RNFL thickness difference.

RESULTS

The study included 4034 children with a mean age of 7.61 ± 0.98 years. The mean global p-RNFL thickness was 106.60 ± 9.41 μm in right eyes and 105.99 ± 9.30 μm in left eyes. The ICC for global p-RNFL difference was 0.866 (95% CI 0.858-0.873, p < 0.001). The symmetry displayed the largest values in nasal inferior quadrant with the ICC value of 0.736 (95% CI 0.721-0.749); and the smallest degree of symmetry was found to be in the superior temporal quadrant with the ICC value of 0.567 (95% CI 0.546-0.588). Axial length (AL) difference was found to have more pronounced correlation to interocular symmetry in p-RNFL thickness with the coefficient of 0.514 (p < 0.001).

CONCLUSIONS

Normal variation in interocular symmetry exists in children. Our results can contribute to the establishment of a standard reference for interocular differences in OCT parameters in children. The interocular differences in AL should be considered in the interpretation of RNFL symmetry, in terms of identifying children at risk of developing glaucoma or other ocular disorders.

Assessment interocular symmetry of peripapillary vessel density in young myopes with optical coherence tomographic angiography

PURPOSE

The purpose of our study was to evaluate the interocular symmetry and distribution of peripapillary vessel density in young myopic eyes.

METHODS

A cross-sectional observational study was designed. A total of 174 eyes of 87 young myopic patients were recruited in this study. According to spherical equivalent (SE), 48 eyes were classified as mild myopia with a mean SE of - 2.12D (SD 0.66D), 66 as moderate myopia with a mean SE of - 4.50D (SD 0.87D), and 60 as high myopia with a mean SE of - 7.39D (SD 1.30D). Optical coherence tomography angiography (OCTA) was used to measure the vessel density. The distribution and interocular symmetry of peripapillary vessel densities were analyzed.

RESULTS

The vessel densities in the whole image, peripapillary, superior and inferior sectors were significantly lower in the high myopia group than in the mild or moderate myopia group (All P < 0.001), and the density in the nasal sector was significantly lower in the high myopia group than in the mild group. And most interesting, the vessel densities in the inside disc and temporal sector showed no difference among the three myopic groups (All P > 0.05). By Pearson correlation analysis, the vessel densities in the whole image, peripapillary, superior, inferior and nasal sectors were negatively correlated with axial length (AL) and SE (All P < 0.001), but vessel densities in the inside disc and temporal sector did not show this correlation (All P > 0.05). Interocular symmetry was observed in all the vascular parameters through paired-samples t-tests (All P > 0.05), intraclass correlation coefficient (ICC) and Pearson correlation analysis (All P < 0.001).

CONCLUSION

The density of radial peripapillary capillaries decreased in the myopic eye with axial elongation, and optical vascular parameters showed significant interocular symmetry among young myopic eyes.

Ganglion Cell Complex Analysis: Correlations with Retinal Nerve Fiber Layer on Optical Coherence Tomography

The aim of this review is to analyze the correlations between the changes in the ganglion cell complex (GCC) and the retinal nerve fiber layer (RNFL) on optical coherence tomography in different possible situations, especially in eyes with glaucoma. For glaucoma evaluation, several studies have suggested that in the early stages, GCC analysis, especially the thickness of the infero and that of the inferotemporal GCC layers, is a more sensitive examination than circumpapillary RNFL (pRNFL). In the moderate stages of glaucoma, inferior pRNFL thinning is better correlated with the disease than in advanced cases. Another strategy for glaucoma detection is to find any asymmetry of the ganglion cell-inner plexiform layers (GCIPL) between the two macular hemifields, because this finding is a valuable indicator for preperimetric glaucoma, better than the RNFL thickness or the absolute thickness parameters of GCIPL. In preperimetric and suspected glaucoma, GCC and pRNFL have better specificity and are superior to the visual field. In advanced stages, pRNFL and later, GCC reach the floor effect. Therefore, in this stage, it is more useful to evaluate the visual field for monitoring the progression of glaucoma. In conclusion, GCC and pRNFL are parameters that can be used for glaucoma diagnosis and monitoring of the progression of the disease, with each having a higher accuracy depending on the stage of the disease.

Macular thickness variation and interocular symmetry by gestational age in preterm school-age children

PURPOSE

To determine changes in macular thickness profile according to gestational age (GA) and to assess interocular symmetry in the macula of children born very preterm.

METHODS

In this cross-sectional study of preterm (n = 106) and term-born (n = 49) children 5-8 years of age at time of examination, optical coherence tomography was used to measure macula thickness as described in the ETDRS study. Statistical analyses included stratified and multivariable analyses.

RESULTS

Foveal minimum thickness increased with decreasing GA (P for trend, <0.001; 254.7 ± 32.8 μm for children born at 24-25 weeks and 193.2 ± 32.8 μm in term-born children). Inner and outer area thickness differed for term and preterm children, but did not vary with the degree of prematurity (inner area, 267.0 ± 11.0 μm for 24-25 weeks' GA and 305.4 ± 11.8 μm for term children [P < 0.01]; outer ring, 305.5 ± 10.4 μm in extreme preterm and 271.0 ± 10.4 μm in term children [P < 0.01]). Interocular asymmetry in preterm children was not significant for most areas; the largest interocular difference was found in the central zone (16.3 ±16.6 μm).

CONCLUSIONS

In our study cohort, children born very preterm examined at school age compared to term born children had greater central thickness with decreased foveal pit, decreased inner ring, and increased thickness of the outer ring. They did not show greater interocular asymmetry.

Intereye structure-function relationship using photopic negative response in patients with glaucoma or glaucoma suspect

We evaluated the intereye structure–function relationship in glaucoma patients using photopic negative response in electroretinogram analysis. Patients with confirmed glaucoma (36 eyes, 36 patients) or suspected glaucoma (19 eyes, 19 patients) were included in this study. Electroretinogram (RETI-scan) was performed with red stimulus on blue background. Intereye comparison for 55 patients was performed between better eyes and worse eyes, which were divided based on average retinal nerve fiber layer (RNFL) thickness measured using spectral-domain optical coherence tomography. In the intereye analysis, PhNR amplitude was lower in worse eyes than in better eyes (P < 0.001). The intereye difference in PhNR amplitude was significantly correlated with intereye difference in average RNFL, as well as average or minimum ganglion cell-inner plexiform layer (GCIPL) thickness (P = 0.006, 0.044, 0.001). In patients with mean deviation ≥ − 6 dB of worse eyes, the intereye difference in PhNR amplitude was significantly associated with intereye difference in average RNFL thickness or minimum GCIPL thickness (P = 0.037, 0.007), but significant correlation was not found between mean sensitivity of visual field tests and structural parameters. In conclusion, PhNR performed well with regard to intereye structure–function association in glaucoma patients, especially at the early stage.

Association of Neuroretinal Thinning and Microvascular Changes with Hypertension in an Older Population in Southern Italy

Background: Retinal microvasculature assessment at capillary level may potentially aid the evaluation of early microvascular changes due to hypertension. We aimed to investigate associations between the measures obtained using optical coherence tomography (OCT) and OCT-angiography (OCT-A) and hypertension, in a southern Italian older population. Methods: We performed a cross-sectional analysis from a population-based study on 731 participants aged 65 years+ subdivided into two groups according to the presence or absence of blood hypertension without hypertensive retinopathy. The average thickness of the ganglion cell complex (GCC) and the retinal nerve fiber layer (RNFL) were measured. The foveal avascular zone area, vascular density (VD) at the macular site and of the optic nerve head (ONH) and radial peripapillary capillary (RPC) plexi were evaluated. Logistic regression was applied to assess the association of ocular measurements with hypertension. Results: GCC thickness was inversely associated with hypertension (odds ratio (OR): 0.98, 95% confidence interval (CI): 0.97–1). A rarefaction of VD of the ONH plexus at the inferior temporal sector (OR: 0.95, 95% CI: 0.91–0.99) and, conversely, a higher VD of the ONH and RPC plexi inside optic disc (OR: 1.07, 95% CI: 1.04–1.10; OR: 1.04, 95% CI: 1.02–1.06, respectively) were significantly associated with hypertension. Conclusion: A neuroretinal thinning involving GCC and a change in capillary density at the peripapillary network were related to the hypertension in older patients without hypertensive retinopathy. Assessing peripapillary retinal microvasculature using OCT-A may be a useful non-invasive approach to detect early microvascular changes due to hypertension.

Comparison of the qualitative and quantitative optical coherence tomographic features between sudden acquired retinal degeneration syndrome and normal eyes in dogs

OBJECTIVE

To quantitatively and qualitatively characterize the retinal optical coherence tomographic features of sudden acquired retinal degeneration syndrome (SARDS) and SARDS suspect dogs.

ANIMALS STUDIED

Fourteen SARDS affected dogs, 11 age-, breed-, and sex-matched control dogs, and two SARDS suspect dogs.

PROCEDURES

Spectral-domain optical coherence tomography (OCT) images were used to evaluate the quantitative features, including thickness, intereye asymmetry, and longitudinal changes in retinal layer thickness and the qualitative features, including retinal architecture and vitreous haze.

RESULTS

Mean outer retinal layer thickness (ORT), outer nuclear layer thickness (ONL), and photoreceptor layer thickness (PRL) were significantly lower in the SARDS group, whereas mean inner retinal layer thickness was significantly higher in the SARDS group than in the control group. While thickness values of all retinal layers did not differ significantly between paired eyes in each group, the absolute intereye asymmetries in the ORT (p < .0001), ONL (p = .008), and PRL (p < .0001) were significantly higher in the SARDS group than in the control group. Some SARDS patients and SARDS suspects had a greater PRL than the control group, and serial OCT evaluation showed an increase in PRL in one SARDS suspect. Vitreous haze severity was greater in the SARDS group than in the control group (vitreous relative intensity, p = .030).

CONCLUSIONS

We described the OCT features of SARDS patients and suspects. In particular, PRL thickening in the SARDS suspects might indicate an early change in SARDS. Although further studies are needed, this finding might provide new insights into the pathogenesis of SARDS.

Interocular symmetry of optical coherence tomography parameters in healthy children and adolescents

Evaluation of interocular asymmetry of optical coherence tomography (OCT) parameters is important for the glaucoma and optic neuropathies. This study was performed to evaluate the interocular asymmetry of OCT parameters in healthy children and adolescents. The circumpapillary retinal nerve fiber layer (RNFL) thickness, optic nerve head (ONH) parameters, and macular ganglion cell-inner plexiform layer (GCIPL) thickness were measured in 620 eyes of 310 healthy children and adolescents using Cirrus HD-OCT. The interocular asymmetry (right eye-left eye) in the OCT parameters was analyzed. The mean ± standard deviation age was 10.3 ± 3.7 years (range 5-17). The right eyes showed thinner superior quadrant RNFL, thicker nasal and temporal quadrant RNFL, lesser rim and disc areas, and thinner average, superior, and superonasal GCIPL than the left eyes (P < 0.05). The 2.5th and 97.5th percentile interocular difference tolerance limits were - 9.0 μm and 11.0 μm for average RNFL thickness, - 0.21 and 0.18 for average cup-to-disc ratio, and - 4.0 μm and 4.0 μm for average GCIPL thickness, respectively. Interocular differences were found in RNFL thickness, ONH parameters, and GCIPL thickness in healthy children and adolescents. These findings should be considered when comparing OCT parameters between the right and left eyes.

FAZSeg: A New Software for Quantification of the Foveal Avascular Zone

Introduction

Various ocular diseases and high myopia influence the anatomical reference point Foveal Avascular Zone (FAZ) dimensions. Therefore, it is important to segment and quantify the FAZs dimensions accurately. To the best of our knowledge, there is no automated tool or algorithms available to segment the FAZ’s deep retinal layer. The paper describes a new open-access software with a Graphical User Interface (GUI) and compares the results with the ground truth (manual segmentation).

Methods

Ninety-three healthy normal subjects included 30 emmetropia and 63 myopic subjects without any sight-threatening retinal conditions, were included in the study. The 6mm x 6mm using the Angioplex protocol (Cirrus 5000 Carl Zeiss Meditec Inc., Dublin, CA) was used, and all the images were aligned with the centre of the fovea. Each FAZ image corresponding to dimensions 420×420 pixels were used in this study. These FAZ image dimensions for the superficial and deep layers were quantified using the New Automated Software Method (NAM). The NAM-based FAZ dimensions were validated with the ground truth.

Results

The age distribution for all 93 subjects was 28.02 ± 10.79 (range, 10.0–66.0) years. For normal subjects mean ± SD age distribution was 32.13 ± 16.27 years. Similarly, the myopia age distribution was 26.06 ± 6.06 years. The NAM had an accuracy of 91.40%. Moreover, the NAM on superficial layer FAZ gave a Dice Similarity Coefficient (DSC) score of 0.94 and Structural Similarity Index Metric (SSIM) of 0.97, while the NAM on deep layer FAZ gave a DSC score of 0.96 and SSIM of 0.98.

Conclusion

A clinician-based GUI software was designed and tested on the FAZ images from deep and superficial layers. The NAM outperformed the device’s inbuilt algorithm when measuring the superficial layer. This open-source software package is in the public domain and can be downloaded online.

Symmetry of Peripapillary-Optical Coherence Tomography Angiography Parameters between Dominant and Non-dominant Eyes in Normal Eyes

Purpose: To assess whether optical coherence tomography (OCT) measurements and peripapillary microvascular parameters measured via optical coherence tomography angiography (OCTA) were similar between the dominant and non-dominant eyes of normal subjects.Methods: We retrospectively analyzed spectral domain OCT and OCTA data on healthy Koreans. The “hole-in-the-card” technique was used to determine ocular dominance. The perfusion density (PD) and flux index (FI) of the peripapillary 4.5 × 4.5-mm area were measured via OCTA. Central macular, peripapillary retinal nerve fiber layer, and macular ganglion cell-inner plexiform layer thicknesses were measured with the aid of spectral-domain OCT. The OCT and OCTA data of dominant and non-dominant eyes were compared.Results: A total of 84 eyes of 42 healthy subjects were analyzed. The average age was 27.3 ± 5.63 years. Twenty-eight subjects (66.7%) were right eye-dominant and 14 (33.3%) left eye-dominant. None of the central macular (260.00 ± 14.16 μm, 258.71 ± 15.18 μm, <i>p</i> = 0.183), macular ganglion cell-inner plexiform layer (82.02 ± 5.07 μm, 82.43 ± 5.60 μm, <i>p</i> = 0.460), or peripapillary retinal nerve fiber layer thickness (99.36 ± 9.27 μm, 97.90 ± 9.46 μm, <i>p</i> = 0.091) differed between the eyes; neither did any OCTA-assessed microvascular parameter.Conclusions: No OCT or OCTA parameter differed between dominant and non-dominant eyes. No parameter identified ocular dominance.

Clinical Use of PanoMap for Glaucoma: Frequently Damaged Areas in Early Glaucoma

PRCIS

Recognizing the shortcomings of poor consistency of the fovea-disc relationship at different time points and comparing PanoMaps may well facilitate the understanding of the spatial relationship between parapapillary and macular areas in glaucoma.

PURPOSE

The aims of this study are to analyze the spatial distribution of the frequently damaged areas in early glaucoma, compare the patterns between nonprogressors and progressors using the combined wide-field parapapillary and macular deviation maps (PanoMap), and to evaluate the consistency of the fovea-disc relationship in PanoMap. The fovea-disc distance (FDD) and fovea-disc axis (FDA) were compared at baseline and at the last follow-up.

MATERIALS AND METHODS

In total, 118 patients with early glaucoma and a minimum follow-up period of 3 years were included in this retrospective observational study. The pattern of structural changes was evaluated by averaging the PanoMaps of the enrolled patients at baseline and last follow-up. Longitudinal comparison of the FDD and FDA was performed at baseline and the last follow-up. Patients were divided into nonprogressor (n=44) and progressor (n=74), and the patterns of glaucoma progression in PanoMaps were compared between them.

RESULTS

At baseline, the glaucomatous damage was found more frequently in the macular compared with the parapapillary area. The spatial distribution of frequently damaged areas was similar between the nonprogressor and progressor. At the last follow-up, compared with the baseline structural change on the PanoMap, the progressive structural changes extended toward the fovea at both the parapapillary and macular areas in the progressor. The FDD and FDA were significantly different between the baseline and the last follow-up.

CONCLUSIONS

The PanoMaps showed a clear spatial distribution of early glaucomatous changes, indicating that the damaged area was frequently observed in the macular area. As the consistency of the fovea-disc relationship in PanoMaps was not excellent, this aspect should be considered when interpreting the PanoMap.

Macular Thickness Profile and Its Association With Best-Corrected Visual Acuity in Healthy Young Adults

Purpose

To describe the thickness profiles of the full retinal and outer retinal layers (ORL) at the macula in healthy young adults, and associations with best-corrected visual acuity (BCVA).

Methods

In total, 1604 participants (19-30 years) underwent an eye examination that included measurements of their BCVA, axial length, and autorefraction. The retinal thickness at the foveal pit and at the nine Early Treatment of Diabetic Retinopathy Study macular regions (0.5-mm radius around the fovea, and superior, inferior, temporal, and nasal quadrants of the inner and outer rings of the macula) were obtained using spectral-domain optical coherence tomography imaging. A custom program was used to correct for transverse magnification effects because of different axial lengths.

Results

The median full retinal and ORL thicknesses at the central macula were 285 µm and 92 µm. The full retina was thinnest centrally and thickest at the inner macula ring, whereas the ORL was thickest centrally and gradually decreased in thickness with increasing eccentricity. There was no association between axial length and the full retinal or ORL thickness. Increased thicknesses of the full retina at the central macula was associated with better BCVA; however, the effect size was small and not clinically significant.

Conclusions

This article mapped the full retinal and ORL thickness profile in a population-based sample of young healthy adults.

Translational Relevance

Thickness values presented in this article could be used as a normative reference for future studies on young adults and in clinical practice.

Comparison of ganglion cell-inner plexiform layer thickness in exfoliative glaucoma and primary open-angle glaucoma

PURPOSE

To determine and compare the thickness of the ganglion cell-inner plexiform layer (GCIPL), the thickness of the retina nerve fiber layer (RNFL), and the parameters of the optic nerve head (ONH) in exfoliative glaucoma (XFG), primary open-angle glaucoma (POAG), and control eyes using optical coherence tomography (OCT).

METHODS

The study was a retrospective observational cross-sectional study of 43 eyes of patients with XFG, 44 eyes of patients with POAG, and 37 eyes of healthy participants. Visual acuity, intraocular pressure, central corneal thickness, rim-area, disc-area, average cup/disc ratio, vertical cup/disc ratio, cup volume, average RNFL thickness, and GCIPL (average, minimum, superior, superotemporal, superonasal, inferior, inferotemporal, and inferonasal) thicknesses were determined.

RESULTS

RNFL thicknesses were similar in the XFG and POAG groups (p = 0.065), and both glaucoma groups had significantly thinner RNFLs than the controls (p = 0.002). The XFG group had significantly thinner average and minimum GCIPLs compared to the POAG and control groups (p = 0.027, p < 0.001 for average thickness and p = 0.038, p < 0.001 for minimum thickness, respectively). No significant difference was found in the ONH parameters among the three groups except for rim-area and cup volume (p > 0.05 for all ONH parameters, p < 0.001 for rim-area, and p = 0.003 for cup volume). Mean visual field mean deviation was -11.6 ± 8.2 dB in the XFG group and -10.4 ± 9.3 dB in the POAG group (p = 0.453).

CONCLUSION

Eyes with XFG were found to have a thinner GCIPL (minimum and average) than eyes with POAG or from healthy controls, although the RNFL measurements were similar to those of eyes with POAG. GCIPL thickness may be a more valuable indicator than RNFL thickness in patients with XFG for early detection of glaucoma and/or for glaucoma progression measurement. There is still some debate in the literature about whether decreases in GCIPL thickness and RNFL thickness (and/or ONH parameter change) are the best indicators for early detection and progress measurement of glaucoma.

Evaluation of Asymmetry in Right and Left Eyes of Normal Individuals Using Extracted Features from Optical Coherence Tomography and Fundus Images

BACKGROUND

Asymmetry analysis of retinal layers in right and left eyes can be a valuable tool for early diagnoses of retinal diseases. To determine the limits of the normal interocular asymmetry in retinal layers around macula, thickness measurements are obtained with optical coherence tomography (OCT).

METHODS

For this purpose, after segmentation of intraretinal layer in threedimensional OCT data and calculating the midmacular point, the TM of each layer is obtained in 9 sectors in concentric circles around the macula. To compare corresponding sectors in the right and left eyes, the TMs of the left and right images are registered by alignment of retinal raphe (i.e. diskfovea axes). Since the retinal raphe of macular OCTs is not calculable due to limited region size, the TMs are registered by first aligning corresponding retinal raphe of fundus images and then registration of the OCTs to aligned fundus images. To analyze the asymmetry in each retinal layer, the mean and standard deviation of thickness in 9 sectors of 11 layers are calculated in 50 normal individuals.

RESULTS

The results demonstrate that some sectors of retinal layers have signifcant asymmetry with P < 0.05 in normal population. In this base, the tolerance limits for normal individuals are calculated.

CONCLUSION

This article shows that normal population does not have identical retinal information in both eyes, and without considering this reality, normal asymmetry in information gathered from both eyes might be interpreted as retinal disorders.

Macular imaging with optical coherence tomography in glaucoma

With the advent of spectral-domain optical coherence tomography, imaging of the posterior segment of the eye can be carried out rapidly at multiple anatomical locations, including the optic nerve head, circumpapillary retinal nerve fiber layer, and macula. There is now ample evidence to support the role of spectral-domain optical coherence tomography imaging of the macula for detection of early glaucoma. Macular spectral-domain optical coherence tomography measurements demonstrate high reproducibility, and evidence on its utility for detection of glaucoma progression is accumulating. We present a comprehensive review of macular spectral-domain optical coherence tomography imaging emerging as an essential diagnostic tool in glaucoma.

Vulnerability Zone of Glaucoma Progression in Combined Wide-field Optical Coherence Tomography Event-based Progression Analysis

Purpose

To investigate the spatial characteristics and patterns of structural progression using the combined retinal nerve fiber layer (RNFL) and ganglion cell–inner plexiform layer event-based progression analysis feature provided by the Guided Progression Analysis (GPA) software of spectral-domain optical coherence tomography.

Methods

In this retrospective observational study, we evaluated 89 patients with open-angle glaucoma showing clinically confirmed structural progression within a minimum follow-up period of 3 years. For each eye, the RNFL and ganglion cell–inner plexiform layer GPA data were extracted from serial spectral-domain optical coherence tomography (HD-OCT 4000, Carl Zeiss Meditec, Inc., Dublin, CA) data from 2012 to 2017 (available in commercial report). A combined wide-field GPA map was merged using vascular landmark-guided superimposition of RNFL and ganglion cell–inner plexiform layer GPA event-based progression maps onto the RNFL image (resulting in the GPA PanoMaps: proposed in this study). The pattern of progressive structural changes was evaluated by comparing the baseline combined wide-field OCT deviation maps (PanoMap deviation maps: available in commercial report) and GPA PanoMaps at the time the first progression was detected and the GPA PanoMaps at the last follow-up. Spatial characteristics and patterns of glaucoma structural progression on GPA PanoMaps were evaluated.

Results

Progressive structural progression was detected most frequently at the macular vulnerability zone (MVZ), with the peripapillary and macular progression being well-correlated spatially. Compared with the baseline structural change on PanoMap, the progressive structural changes extended toward the fovea at both the peripapillary and macular areas. A spatial difference was observed between the areas where structural damage was frequently found on PanoMap (peripapillary inferoinferior sector and macular MVZ) and areas where progression was frequently found on GPA PanoMap (peripapillary and macular MVZ).

Conclusions

The patterns of progressive glaucomatous structural changes in both the peripapillary and macular areas were confirmed on the combined wide-field GPA map (GPA PanoMap). An analysis of the progression pattern using the GPA PanoMap facilitates the understanding of the spatial relation between the peripapillary and macular areas in glaucoma.

Heritability of macular ganglion cell inner plexiform layer thickness as determined by optical coherence tomography: the Healthy Twin Study

PURPOSE

To evaluate genetic influence on macular ganglion cell inner plexiform layer (GCIPL) thickness.

METHODS

Macular GCIPL thickness was measured with optical coherence tomography in nine macular subfields defined by the E TDRS. Intraclass correlation coefficients (ICC) of GCIPL thickness by different types of family relationships were estimated to assess intrafamilial resemblance. Then, heritability of GCIPL thickness was estimated.

RESULTS

Three hundred and sixty-one Korean adults from 89 families with normal healthy eyes were included. GCIPL thickness was highest in inner subfields and lowest in fovea. Monozygotic twin pairs showed significantly higher ICCs of GCIPL thickness in all subfields compared to those in parent-offspring pairs and sibling pairs. GCIPL thickness was highly heritable in the centre (0.71) and outer subfields but moderate to highly heritable in inner subfields. Heritability of GCIPL thickness in outer subfields was 0.69, 0.67, 0.72 and 0.68 for superior, inferior, temporal and nasal fields, respectively. Heritability of GCIPL thickness in inner subfields was 0.55, 0.56, 0.75 and 050 for superior, inferior, temporal and nasal subfields, respectively.

CONCLUSION

Macular GCIPL thickness is significantly influenced by genetic factors. It varies according to subfields with moderate to high heritability in all subfields.

Assessing Ganglion Cell Layer Topography in Human Albinism Using Optical Coherence Tomography

Purpose

To test whether ganglion cell layer (GCL) and inner plexiform layer (IPL) topography is altered in albinism.

Methods

Optical coherence tomography scans were analyzed in 30 participants with albinism and 25 control participants. Horizontal and vertical line scans were acquired at the fovea, then strip registered and averaged. The Duke Optical Coherence Tomography Retinal Analysis Program was used to automatically segment the combined GCL and IPL and total retinal thickness, followed by program-assisted manual segmentation of the boundary between the GCL and IPL. Layer thickness and area under the curve (AUC) were calculated within 2.5 mm of the fovea. Nasal-temporal and superior-inferior asymmetry were calculated as an AUC ratio in each quadrant.

Results

GCL and IPL topography varied between participants. The summed AUC in all quadrants was similar between groups for both the GCL (P = 0.84) and IPL (P = 0.08). Both groups showed nasal-temporal asymmetry in the GCL, but only participants with albinism had nasal-temporal asymmetry in the IPL. Nasal-temporal asymmetry was greater in albinism for both the GCL (P < 0.0001) and the IPL (P = 0.0006). The GCL usually comprised a greater percentage of the combined GCL and IPL in controls than in albinism.

Conclusions

The GCL and IPL have greater structural variability than previously reported. GCL and IPL topography are significantly altered in albinism, which suggests differences in the spatial distribution of retinal ganglion cells. This finding provides insight into foveal development and structure-function relationships in foveal hypoplasia.

Interobserver reproducibility and interocular symmetry of the macular ganglion cell complex: assessment in healthy children using optical coherence tomography

Background

Assessment of interobserver reproducibility and interocular symmetry using optical coherence tomography (OCT)–based measurements of the macular ganglion cell complex (GCC) in healthy children facilitates interpretation of OCT data. We assessed the interobserver reproducibility and interocular symmetry of GCC and evaluated candidate determinants.

Methods

This was a cross-sectional study performed in a primary and tertiary health-care setting. A total of 126 healthy participants aged 5 to 18 years were eligible. GCC scans were performed by 4 operators using the Topcon 3D OCT-2000 device. Intraclass correlation coefficients (ICCs) were used to estimate reproducibility and symmetry. Cut-off points for symmetry were defined as the 95th percentile of the absolute interocular difference for 6 GCC parameters. Percentile distributions of interocular difference were generated based on age and difference in absolute interocular spherical equivalent (SE).

Results

The reproducibility ICC ranged from 0.96 to 0.98 for all 6 GCC parameters. Cut-off points for interocular symmetry of the superior and inferior quadrants and total macular retinal nerve fibre layer thickness (mRNFL) and macular ganglion cell layer-inner plexiform layer thickness were 3.5, 4.5, 3.0, 3.0, 2.5, and 2.5 μm respectively. A positive association was observed between the absolute interocular difference of SE and superior and total mRNFL symmetry values (p = 0.047 and p = 0.040, respectively).

Conclusions

OCT measurements of GCC in healthy children show excellent reproducibility. Interocular differences in SE should be assessed when mRNFL differences exceed the 95% cut-off. These findings can contribute to establish reference values for interocular symmetry in paediatric GCC parameters.

Antenatal and postpartum comparison of HD-OCT findings of macula, retinal nerve fiber layer, ganglion cell density between severe preeclampsia patients and healthy pregnant woman

AIM

To investigate the effects of severe preeclampsia on the retinal nerve fiber layer (RNFL), macula thickness and ganglion cell density in pregnancy and postpartum, using High Definition Optical Coherence Tomography (HD-OCT).

MATERIAL AND METHOD

The study group included 28 stable pregnant patients diagnosed with severe preeclampsia and the control group, 28 age and gestational week-matched healthy pregnant women. HD-OCT measurements were taken by the same researcher using a Cirrus HD-OCT device and were repeated at 8 weeks postpartum.

RESULTS

The mean systolic pressure, diastolic pressure, and intraocular perfusion pressure (IPP) values measured in pregnacy were determined to be higher in the preeclampsia group than in the control group (158.4 ± 7.3 vs.113.6 ± 6.8, 97.0 ± 5.7vs.73.8 ± 5.9 and 68.1 ± 3.9 vs.48.8 ± 3.3 mm Hg, respectively) (p < 0.05 for all). The mean RNFL, macula thickness, ganglion cell analysis, and intraocular pressure (IOP) values during pregnancy were determined to be similar in both groups (p > 0.05 for all). No significant difference was determined postpartum between the groups in respect of mean systolic pressure, diastolic pressure, RNFL, macula thickness, ganglion cell analysis, and IOP values (114.3 ± 5.0 vs 114.6 ± 5.9 mm Hg, 74.6 ± 5.1 vs.74.5 ± 5.5 mm Hg, 96.0 ± 7.3 vs. 95.9 ± 6.7 µm, 228.2 ± 18.9 vs.234.5 ± 15.4 µm, 81.8 ± 8.0 vs. 84.2 ± 4.6 µm, 14.1 ± 2.4 vs.13.8 ± 2, respectively) (p < 0.05 for all). Mean IPP during pregnancy was higher than the mean postpartum IPP in the severe pre-eclampsia group (68.1 ± 3.9 vs 49.1 ± 3.1 mm Hg) (p < 0.001).

CONCLUSION

This is the first study to have evaluated ganglion cell density of the retina, macula thickness, and RNFL using HD-OCT in severe pre-eclampsia cases, both during pregnancy and postpartum.

Bilateral asymmetry improved accuracy when assessing glaucomatous vision-related quality of life impairment

Bilateral asymmetry has been used in optical coherence tomography tests to find early damage to the optic nerve. However, limited studies have quantitatively evaluated bilateral asymmetry in electrophysiological disorders in patients with glaucoma. The aim of the study was to evaluate bilateral asymmetry in pattern visual evoked potentials (PVEPs) and conventional clinical markers as well as its potential use in detecting glaucomatous impairment. After investigating 60 glaucomatous patients (120 eyes) and 65 age and sex-matched normal control subjects (130 eyes) using uni- and multivariable analysis, we found that vision-related quality of life (VRQOL) impairment was significantly associated with larger bilateral asymmetry index (BAI) of clinical markers. Rasch-calibrated National Eye Institute Visual Function Questionnaire-25 scores were significantly associated with the BAI in PVEPs latency in 15 minutes check size (β = -0.478, 95% confidence interval [CI], -0.708 to -0.248, P < .001) and the BAI in visual field mean deviation (β = -0.249, 95% CI, -0.454 to -0.044, P = .018) according to multivariable analysis. Bilateral asymmetry in objective and subjective functional measurements was quantitatively associated with glaucomatous VRQOL impairment. This finding may help bridge the gap in understanding between patients and clinicians, and increase awareness of how glaucomatous neuropathic progression may interfere with patients' daily life.

Serial Combined Wide-Field Optical Coherence Tomography Maps for Detection of Early Glaucomatous Structural Progression

Importance

Both parapapillary and macular areas are important in determining the progression of early glaucoma. However, no attempt has been made to assess the progression of glaucoma in images that combine the 2 areas.

Objective

To evaluate the potential usefulness of serial analysis of combined wide-field optical coherence tomography (OCT) maps for detection of structural progression in patients with early glaucoma.

Design, Setting, and Participants

Retrospective observational study. Patients with early primary open-angle glaucoma with a minimum of 3-year follow-up involving serial spectral-domain OCT measurement were analyzed. Patients were divided into a nonprogressor group (n = 47) and a progressor group (n = 47) on the basis of serial stereo disc photography and red-free photography. Serial combined wide-field OCT maps integrating parapapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) maps were generated with the embedded software of serial spectral-domain OCT. Glaucoma specialists then assessed the structural progression detection ability of those serial wide-field OCT maps for early glaucomatous eyes and compared their sensitivity with those of RNFL and GCIPL guided progression analyses (GPAs).

Main Outcomes and Measures

The diagnostic ability of the serial wide-field OCT maps for early glaucomatous structural progression.

Results

Ninety-four patients (mean [SD] age, 51.4 [12.3] years; 48 [51.1%] women; all Korean) were included. The serial wide-field OCT map analysis showed good agreement for detection of structural progression between the 2 glaucoma graders (wide-field OCT thickness map: κ = 0.649; wide-field OCT deviation map: κ = 0.833). These maps showed early glaucomatous structural progression detection abilities comparable with those of RNFL and GCIPL GPAs (sensitivities of wide-field OCT thickness map, wide-field OCT deviation map, RNFL GPA, and GCIPL GPA = 63.8%, 83.0%, 83.0%, and 66.0%, respectively, all P > .05; specificities of wide-field OCT thickness map, wide-field OCT deviation map, RNFL GPA, and GCIPL GPA = 93.6%, 95.7%, 84.8%, and 93.6%, respectively, all P > .05).

Conclusions and Relevance

The serial combined wide-field OCT maps integrating RNFL and GCIPL maps performed well in detecting structural progression in early glaucomatous eyes. Confirmation in an independent prospective study might provide greater confidence in this conclusion.

The HD-OCT Study May Be Useful in Searching for Markers of Preclinical Stage of Diabetic Retinopathy in Patients with Type 1 Diabetes

The aim of the study was to analyze the thickness of individual retinal layers in patients with type 1 diabetes (T1D) in comparison to the control group and in relation to markers of diabetes metabolic control. The study group consisted of 111 patients with an average of 6-years of T1D duration. The control group included 36 gender- and age-matched individuals. In all patients optical coherence tomography (OCT) study was performed using HD-OCT Cirrus 5000 with evaluation of optic nerve head (ONH) parameters, thickness of retinal nerve fiber layer (RNFL) with its quadrants, macular full-thickness parameters, ganglion cells with inner plexus layer (GCIPL) and choroidal thickness (CT). Lower disc area value was observed in the study group as compared to controls (p = 0.0215). Negative correlations were found both between age at examination and rim area (R = −0.28, p = 0.0007) and between superior RNFL thickness and duration of diabetes (R = −0.20, p = 0.0336). Positive correlation between center thickness and SD for average glycemia (R = 0.30, p = 0.0071) was noted. Temporal CT correlated positively with age at examination (R = 0.21, p = 0.0127). The selected parameters the HD-OCT study may in the future serve as potential markers of preclinical phase of DR in patients with T1D.

Spectral-Domain OCT Measurements in Alzheimer's Disease: A Systematic Review and Meta-analysis

TOPIC

OCT is a noninvasive tool to measure specific retinal layers in the eye. The relationship of retinal spectral-domain (SD) OCT measurements with Alzheimer's disease (AD) and mild cognitive impairment (MCI) remains unclear. Hence, we conducted a systematic review and meta-analysis to examine the SD OCT measurements in AD and MCI.

CLINICAL RELEVANCE

Current methods of diagnosing early AD are expensive and invasive. Retinal measurements of SD OCT, which are noninvasive, technically simple, and inexpensive, are potential biomarkers of AD.

METHODS

We conducted a literature search in PubMed and Excerpta Medica Database to identify studies published before December 31, 2017, that assessed the associations between AD, MCI, and measurements of SD OCT: ganglion cell-inner plexiform layer (GC-IPL), ganglion cell complex (GCC), macular volume, and choroidal thickness, in addition to retinal nerve fiber layer (RNFL) and macular thickness. We used a random-effects model to examine these relationships. We also conducted meta-regression and assessed heterogeneity, publication bias, and study quality.

RESULTS

We identified 30 eligible studies, involving 1257 AD patients, 305 MCI patients, and 1460 controls, all of which were cross-sectional studies. In terms of the macular structure, AD patients showed significant differences in GC-IPL thickness (standardized mean difference [SMD], -0.46; 95% confidence interval [CI], -0.80 to -0.11; I2 = 71%), GCC thickness (SMD, -0.84; 95% CI, -1.10 to -0.57; I2 = 0%), macular volume (SMD, -0.58; 95% CI, -1.03 to -0.14; I2 = 80%), and macular thickness of all inner and outer sectors (SMD range, -0.52 to -0.74; all P < 0.001) when compared with controls. Peripapillary RNFL thickness (SMD, -0.67; 95% CI, -0.95 to -0.38; I2 = 89%) and choroidal thickness (SMD range, -0.88 to -1.03; all P < 0.001) also were thinner in AD patients.

CONCLUSIONS

Our results confirmed the associations between retinal measurements of SD OCT and AD, highlighting the potential usefulness of SD OCT measurements as biomarkers of AD.

Inner macular layer thickness by spectral domain optical coherence tomography in children and adults: a hospital-based study

Purpose

To establish the normative ranges of macular ganglion cell layer (mGCL) and macular inner plexiform layer (mIPL) thickness using Spectralis spectral domain optical coherence tomography (SD-OCT) (Heidelberg Engineering, Inc., Heidelberg, Germany) in both Korean children and adults, and to determine factors associated with mGCL and mIPL thickness.

Methods

We conducted a retrospective, observational study of 573 healthy subjects (5–70 years old) who underwent comprehensive ophthalmic examinations in a single institution. Each inner retinal layer thickness was measured using SD-OCT and automatic segmentation software. Cross-sectional analysis was used to evaluate the effect of gender, age and ocular parameters on mGCL and mIPL thickness. Normative ranges of mGCL and mIPL thickness according to age, gender and factors associated with mGCL and mIPL thickness were measured.

Results

The mean mGCL and mIPL thickness were 40.6±2.8 and 33.8±2.0 µm, respectively. Determinants of inner sector mGCL thickness were circumpapillary retinal nerve fibre layer (cpRNFL) thickness (β=1.172, p<0.001), age (β=−0.019, p=0.021) and male gender (β=1.452, p<0.001). Determinants of inner sector mIPL thickness were cpRNFL (β=0.952, p<0.001) and male gender (β=1.163, p<0.001). The inner sector mGCL and mIPL thickness increased significantly with age in children (β=0.174, p=0.009 and β=0.115, p=0.013), and then decreased in adults (β=−0.070, p<0.001 and β=−0.024, p=0.032). In the case of outer sectors, mGCL and mIPL thickness were not significantly related to age and gender.

Conclusions

This study ensured a normative range of the mGCL and mIPL thickness using Spectralis OCT. Gender, age and cpRNFL thickness significantly correlated with mGCL and mIPL thickness. This information should be considered in the interpretation of SD-OCT data.

Combined Use of Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Event-based Progression Analysis

PURPOSE

To evaluate patterns of glaucomatous structural progression using the combined retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) event-based progression analysis feature provided by spectral-domain optical coherence tomography (SD-OCT)'s - (GPA) software.

DESIGN

Retrospective observational case series.

METHODS

Seventy-nine (79) patients were identified with open-angle glaucoma (OAG) showing clinically confirmed structural progression within a minimum 3-year follow-up period. For each eye, RNFL and GCIPL GPA data were obtained from serial SD-OCT data from 2012 to 2017. An integrated GPA map thereafter was merged by vascular landmark-guided superimposition of RNFL and GCIPL GPA event-based progression maps onto the RNFL imagery (resulting in what we call the GPA PanoMap). The GPA PanoMap progression patterns were classified as (1) RNFL-only, (2) GCIPL-only, (3) concurrent (both RNFL and GCIPL), (4) GCIPL after RNFL, and (5) RNFL after GCIPL. The locations of structural progression were classified, based on an earlier schematic model, as (1) superior vulnerability zone (SVZ), (2) papillomacular bundle (PM), (3) macular vulnerability zone (MVZ), and (4) inferoinferior portion. Structural progression patterns on the GPA PanoMap were evaluated according to the location of progression. Among the eyes with progression in the inferior hemiretina, structural progression patterns on the GPA PanoMap were evaluated according to the baseline structural damage.

RESULTS

On the GPA PanoMap, when structural progression was located in the SVZ or inferoinferior portion, it was detected only in the RNFL area; when progression was located in the PM or MVZ, various patterns were observed, among which the concurrent pattern was the majority in both areas (43.8% and 45.6% in the PM and MVZ, respectively). Among the eyes with progression in the inferior hemiretina (n = 66), the location of progression varied but did not differ significantly according to the baseline deviation map (P = .440). The progression patterns of MVZ were significantly different among the baseline deviation map patterns (P = .023); however, all of the progression patterns of the inferoinferior portion were RNFL-only.

CONCLUSION

The various progression patterns were confirmed according to the locations and baseline patterns of glaucomatous structural change on the integrated GPA map (GPA PanoMap). Combined use of RNFL and GCIPL GPA or the GPA PanoMap could be useful for determination of structural progression and understanding of its patterns in patients with glaucoma.

Ganglion cell-inner plexiform layer thickness by swept-source optical coherence tomography in healthy Korean children: Normative data and biometric correlations

The purpose of this study was to identify the normative values of ganglion cell-inner plexiform layer (GCIPL) thickness in healthy Korean children using swept-source optical coherence tomography (SS-OCT) and to investigate the correlations of age, refractive error, axial length (AL), retinal nerve fiber layer (RNFL) thickness and cup-to-disc (C/D) ratio with GCIPL thickness. Children aged between 3 and 17 who had visited our pediatric ophthalmology clinic were enrolled. Each subject underwent full ophthalmic examinations including RNFL thickness, C/D ratio and GCIPL thickness measurement by SS-OCT as well as AL measurement by partial-coherence interferometry. A total of 254 eyes of 127 children were included. The mean average GCIPL thickness was 71.5 ± 5.35 μm; the thickest sector was the superonasal and the thinnest the inferior. According to multivariate regression analysis, average GCIPL thickness was significantly associated with spherical equivalent and RNFL thickness (P < 0.0001 for both): the higher the myopia or the thinner the RNFL thickness, the thinner the GCIPL thickness. In conclusion, this study provides an SS-OCT-based pediatric normative database of GCIPL thickness that can serve as a reference for early detection and follow-up of glaucoma and optic nerve diseases in children.

Frequent retinal ganglion cell damage after acute optic neuritis

BACKGROUND

To identify the extent of ganglion cell damage after first-time optic neuritis (ON) using the inter-ocular difference between affected and fellow eyes, and whether this approach is able to detect more patients suffering from ganglion cell damage than using absolute values.

METHODS

Thirty-four patients with first-time unilateral ON were followed for a median 413 days. Patients underwent optical coherence tomography testing to determine ganglion cell plus inner plexiform layer thickness (GCIP). Ganglion cell loss was quantified as GCIP difference between ON-affected and fellow eyes (inter-GCIP) and was compared against measurements from 93 healthy controls (HC). Visual function was assessed with high contrast visual acuity; and standard automated perimetry-derived measures of mean deviation and foveal threshold.

RESULTS

At clinical presentation after median 19 days from symptom onset, 47.1% of patients showed early GCIP thinning in the ON-affected eye based on inter-GCIP. At the last visit acute ON was associated with 16.1 ± 10.0 µm GCIP thinning compared to fellow eyes (p = 3.669e-06). Based on inter-GCIP, 84.9% of ON patients sustained GCIP thinning in their affected eye at the last visit, whereas using absolute values only 71.0% of patients suffered from GCIP thinning (p = 0.002076). Only 32.3% of these patients had abnormal visual function. The best predictor of GCIP thinning as a measure of ON severity at the last visit was worse visual field mean deviation at clinical presentation.

CONCLUSION

Inter-ocular GCIP identifies significantly more eyes suffering damage from ON than absolute GCIP, visual fields or visual acuity loss. Effective interventional options are needed to prevent ganglion cell loss.

Lateral thinking - Interocular symmetry and asymmetry in neurovascular patterning, in health and disease

No biological system or structure is likely to be perfectly symmetrical, or have identical right and left forms. This review explores the evidence for eye and visual pathway asymmetry, in health and in disease, and attempts to provide guidance for those studying the structure and function of the visual system, where recognition of symmetry or asymmetry may be essential. The principal question with regards to asymmetry is not 'are the eyes the same?', for some degree of asymmetry is pervasive, but 'when are they importantly different?'. Knowing if right and left eyes are 'importantly different' could have significant consequences for deciding whether right or left eyes are included in an analysis or for examining the association between a phenotype and ocular parameter. The presence of significant asymmetry would also have important implications for the design of normative databases of retinal and optic nerve metrics. In this review, we highlight not only the universal presence of asymmetry, but provide evidence that some elements of the visual system are inherently more asymmetric than others, pointing to the need for improved normative data to explain sources of asymmetry and their impact on determining associations with genetic, environmental or health-related factors and ultimately in clinical practice.

Ganglion Cell-Inner Plexiform Layer, Peripapillary Retinal Nerve Fiber Layer, and Macular Thickness in Eyes with Myopic β-Zone Parapapillary Atrophy

Purpose. To assess the correlations of myopic β-zone parapapillary atrophy (β-PPA) with the optic nerve head (ONH) and retina. Methods. We selected 27 myopic patients who showed prominent β-PPA in one eye and no β-PPA in the other eye. We studied their macula, macular ganglion cell-inner plexiform layer (mGCIPL), peripapillary retinal nerve fiber layer (pRNFL) thickness, and ONH parameters using optical coherence tomography. Results. The average of five out of six sectors and minimum values of mGCIPL thicknesses in eyes with prominent β-PPA discs were significantly less than those of the control eyes. The results of clock-hour sector analyses showed significant differences for pRNFL thickness in one sector. In the ONH analyses, no significant difference was observed between myopic β-PPA and control eyes. The macular thickness of the β-PPA eyes was thinner than control eyes in all sectors. There was a significant difference between the two groups in three sectors (the inner superior macula, inner temporal macula, and inner inferior macula) but there was no significant difference in the other sectors, including the fovea. Conclusions. The myopic β-PPA eyes showed thinner mGCIPL, parafovea, and partial pRNFL layers compared with myopic eyes without β-PPA.

Asymmetry Analysis of Macular Inner Retinal Layers for Glaucoma Diagnosis: Swept-Source Optical Coherence Tomography Study

PURPOSE

To report an asymmetry analysis of macular inner retinal layers using swept-source optical coherence tomography (OCT) and to evaluate the utility for glaucoma diagnosis.

DESIGN

Observational, cross-sectional study.

PARTICIPANTS

Seventy normal healthy subjects and 62 glaucoma patients.

METHODS

Three-dimensional scans were acquired from 70 normal subjects and 62 open angle glaucoma patients by swept-source OCT. The thickness of the retinal nerve fiber layer, ganglion cell-inner plexiform layer (GCIPL), ganglion cell complex, and total retina were calculated within a 6.2×6.2 mm macular area divided into a 31×31 grid of 200×200 μm superpixels. For each of the corresponding superpixels, the thickness differences between the subject eyes and contra-lateral eyes and between the upper and lower macula halves of the subject eyes were determined. The negative differences were displayed on a gray-scale asymmetry map. Black superpixels were defined as thickness decreases over the cut-off values.

RESULTS

The negative inter-ocular and inter-hemisphere differences in GCIPL thickness (mean ± standard deviation) were -2.78 ± 0.97 μm and -3.43 ± 0.71 μm in the normal group and -4.26 ± 2.23 μm and -4.88 ± 1.46 μm in the glaucoma group. The overall extent of the four layers' thickness decrease was larger in the glaucoma group than in the normal group (all Ps<0.05). The numbers of black superpixels on all of the asymmetry maps were larger in the glaucoma group than in the normal group (all Ps<0.05). The area under receiver operating characteristic curves of average negative thickness differences in macular inner layers for glaucoma diagnosis ranged from 0.748 to 0.894.

CONCLUSIONS

The asymmetry analysis of macular inner retinal layers showed significant differences between the normal and glaucoma groups. The diagnostic performance of the asymmetry analysis was comparable to that of previous methods. These findings suggest that the asymmetry analysis can be a potential ancillary diagnostic tool.

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

Background

The aim of this study was to determine the interocular differences in the peripapillary retinal nerve fibre layer (RNFL), peripapillary choroidal thickness (PCT) and subfoveal choroidal thickness (SFCT) in healthy adults with isometropia, using enhanced depth imaging optical coherence tomography (EDI SD-OCT).

Methods

One hundred healthy Chinese adults with spherical equivalents of ≤ ±3 dioptres and interocular differences of <0.5 dioptres were prospectively enrolled in this study. They underwent RNFL and PCT measurements via EDI SD-OCT, with a 3.4 mm scan circle centred on the optic nerve head. Subfoveal choroidal thickness (SFCT) measurements were also taken with a horizontal line scan centred on the macula. Right and left eyes were compared by a paired t-test, and the interocular differences were calculated. The agreement and correlations of the RNFLs, PCTs and SFCTs between the right and left eyes were analysed.

Results

Eighty-six subjects (172 eyes) were included in the final analysis, consisting of 44 (51.6 %) males and 42 (48.8 %) females; 55 (63.9 %) had emmetropia and 33 (36.1 %) had ametropia. The RNFL was statistically significantly thicker in the right eyes when compared to the left eyes in the temporal quadrant, and thinner on average in the nasal superior quadrant (p < 0.05). However, the differences in the choroidal thicknesses in all of the quadrants between the right and left eyes were not statistically significant. The tolerance limits of the average RNFL were −21.1 μm and 7.1 μm, and the mean and standard deviation of the interocular difference in the average PCT was −2.2 ± 24.2 μm. The RNFLs and PCTs in all of the locations in the right eyes were significantly correlated with those in the left eyes. However, no significant associations between the age, sex, interocular asymmetry of spherical the equivalent or interocular differences in the RNFL and PCT were detected.

Conclusion

The PCT did not differ significantly between the right and left eyes, although interocular asymmetry of the RNFL existed in this Chinese population with isometropia.

Interocular Symmetry of Macular Ganglion Cell Complex Thickness in Young Chinese Subjects

Purpose

To report interocular differences in macular ganglion cell complex (mGCC) thickness in young Chinese subjects using RTVue-100 optical coherence tomography (OCT).

Methods

This was an observational, cross-sectional study. The mGCC thickness was measured in 158young Chinese subjects using RTVue-100 OCT. The normal ranges of the interocular differences were determined as falling between the 2.5th and 97.5th percentiles. Right and left eyes were compared using a paired t test. Pearson correlation analysis was performed to assess the relationships between mGCC thickness and other potential factors. The relationships between the interocular difference in the average mGCC thickness and the potential factors were evaluated by univariate and multivariate linear regression analysis.

Results

The mean interocular difference in the average, superior, and inferior mGCC thickness were 0.19 ± 2.69 μm, 0.22 ±3.14 μm, and 0.25±3.34 μm, respectively, which were not statistically significant. The 2.5th and 97.5th percentiles of interocular difference for mean average mGCC thickness were -4.82μm and 4.38μm, for superior mGCC thickness, -6.67 μm and 7.04 μm, and for inferior mGCC thickness, -6.75 μm and 6.27 μm. There was a strong correlation between the right and left eyes for all the studied parameters, including spherical equivalent (SE) and axial length (AL). Interocular difference in SE (p = 0.007) were independently correlated with the interocular difference in average mGCC thickness.

Conclusions

There was no significant relative interocular difference in mGCC thickness in young Chinese subjects. Interocular difference exceeding the normal limits should be considered significantly asymmetrical, and suggestive of pathology.

Prevalence and Distribution of Segmentation Errors in Macular Ganglion Cell Analysis of Healthy Eyes Using Cirrus HD-OCT

Purpose

To determine the frequency of different types of spectral domain optical coherence tomography (SD-OCT) scan artifacts and errors in ganglion cell algorithm (GCA) in healthy eyes.

Methods

Infrared image, color-coded map and each of the 128 horizontal b-scans acquired in the macular ganglion cell-inner plexiform layer scans using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) macular cube 512 × 128 protocol in 30 healthy normal eyes were evaluated. The frequency and pattern of each artifact was determined. Deviation of the segmentation line was classified into mild (less than 10 microns), moderate (10–50 microns) and severe (more than 50 microns). Each deviation, if present, was noted as upward or downward deviation. Each artifact was further described as per location on the scan and zones in the total scan area.

Results

A total of 1029 (26.8%) out of total 3840 scans had scan errors. The most common scan error was segmentation error (100%), followed by degraded images (6.70%), blink artifacts (0.09%) and out of register artifacts (3.3%). Misidentification of the inner retinal layers was most frequent (62%). Upward Deviation of the segmentation line (47.91%) and severe deviation (40.3%) were more often noted. Artifacts were mostly located in the central scan area (16.8%). The average number of scans with artifacts per eye was 34.3% and was not related to signal strength on Spearman correlation (p = 0.36).

Conclusions

This study reveals that image artifacts and scan errors in SD-OCT GCA analysis are common and frequently involve segmentation errors. These errors may affect inner retinal thickness measurements in a clinically significant manner. Careful review of scans for artifacts is important when using this feature of SD-OCT device.

In vivo evaluation of retinal ganglion cells degeneration in eyes with branch retinal vein occlusion

PURPOSE

To analyse the topographic changes in retinal ganglion cells (RGCs) in eyes with unilateral naive branch retinal vein occlusion (BRVO) in comparison to normal fellow eyes and to healthy control eyes.

METHODS

We performed a retrospective analysis of 66 eyes (33 subjects) with naive unilateral BRVO who underwent spectral-domain optical coherence tomography using Cirrus HD-OCT. We also included 67 eyes of 48 age-matched healthy volunteers as control group. Average, minimum and sectoral macular ganglion cell-inner plexiform layer (GCIPL) thickness, macular retinal nerve fibre layer (RNFL) thickness and outer retinal thickness were collected. Comparison of the GCIPL, RNFL and outer retinal thicknesses among study eyes, normal fellow eyes and control groups was performed.

RESULTS

The average and minimum macular GCIPL thicknesses were constantly and diffusely reduced in BRVO compared with normal fellow eyes and healthy controls (p<0.001 for each GCIPL sector). The average macular RNFL thickness was reduced in BRVO eyes compared with normal fellow eyes (p=0.01) and tended to be lower than controls (p=0.07). The minimum RNFL thickness in eyes with BRVO was significantly reduced when compared with fellow eyes (p<0.001) and control eyes (p<0.001). The average outer retina thickness was thicker in BRVO eyes compared with both fellow eyes (p<0.001) and controls (p<0.001).

CONCLUSIONS

A significant reduction of the macular GCIPL and RNFL thicknesses was observed in eyes with BRVO. This finding is suggestive of RGCs degeneration; the neuroprotective effect of current therapeutic options might be an important consideration when evaluating treatment strategies and prognosticating visual outcome in BRVO eyes.

Comparative glaucomatous diagnosis using macular optical coherence tomography and perimetry with centrally condensed stimuli: English version

The presentation and measurement of the internal retinal layers by current optical coherence tomography (OCT) instruments allow a precise topographic localization of macular glaucomatous damage. Ganglion cell analysis in particular can reveal slight central defects and can effectively be correlated with perimetric strategies with centrally condensed stimuli, so that small glaucomatous defects can be confirmed earlier and more confidently. Progression can also be verified in the early stages of the disease as enlargement and deepening of small localized defects. Macular OCT (mOCT) cannot sufficiently detect peripheral glaucomatous defects and may be impaired by macular pathologies; therefore, mOCT should be combined with other morphometric examinations. In order to take advantage of the technical capabilities of current OCT devices appropriate perimetric strategies should also be applied. As the algorithms for documentation and evaluation of the results of current OCT instruments are far less advanced than the technical capabilities, OCT results still have to be visually scrutinized together with the visual field results to benefit from the technical possibilities provided by modern OCT devices.

[Correlation of morphological and functional glaucoma diagnostics with macular OCT and perimetry with centrally condensed stimuli: German version]

The presentation and measurement of the internal retinal layers by current optical coherence tomography (OCT) instruments allow a precise topographic localization of macular glaucomatous damage. Ganglion cell analysis in particular can reveal slight central defects and can effectively be correlated with perimetric strategies with centrally condensed stimuli, so that small glaucomatous defects can be confirmed earlier and more confidently. Progression can also be verified in the early stages of the disease as enlargement and deepening of small localized defects. Macular OCT (mOCT) cannot sufficiently detect peripheral glaucomatous defects and may be impaired by macular pathologies; therefore, mOCT should be combined with other morphometric examinations. In order to take advantage of the technical capabilities of current OCT devices appropriate perimetric strategies should also be applied. As the algorithms for documentation and evaluation of the results of current OCT instruments are far less advanced than the technical capabilities, OCT results still have to be visually scrutinized together with the visual field results to benefit from the technical possibilities provided by modern OCT devices.

Diagnostic ability of macular ganglion cell asymmetry for glaucoma

BACKGROUND

Using spectral-domain optical coherence tomography (OCT), this study aims to investigate the glaucoma diagnostic ability of macular ganglion cell asymmetry analysis.

DESIGN

A cross-sectional study was conducted. This study was performed to investigate glaucoma diagnostic ability of macular ganglion cell asymmetry analysis in eyes with various degrees of glaucoma.

PARTICIPANTS

We enrolled 181 healthy eyes and 265 glaucomatous eyes.

METHODS

Glaucomatous eyes were subdivided into pre-perimetric, early, moderate and advanced-to-severe glaucoma based on visual field test results. For each eye, macular ganglion cell-inner plexiform layer (GCIPL) thickness was measured using OCT. Average GCIPL thickness, GCIPL thicknesses in superior and inferior hemispheres, absolute difference in GCIPL thickness between superior and inferior hemispheres and GCIPL asymmetry index calculated as the absolute value of log10 (inferior hemisphere thickness/superior hemisphere thickness) were analysed.

MAIN OUTCOME MEASURES

Areas under the receiver operating characteristics curves (AUCs) of GCIPL parameter were calculated and compared.

RESULTS

All of the GCIPL parameters showed good glaucoma diagnostic ability (AUCs ≥ 0.817, P < 0.01). AUCs of average, superior and inferior GCIPL thickness increased as the severity of glaucoma increased. GCIPL thickness difference and asymmetry index showed the highest AUCs in early and moderate glaucoma and lower AUCs in pre-perimetric and advanced-to-severe glaucoma. GCIPL thickness difference and asymmetry index showed better glaucoma diagnostic ability than other GCIPL parameters only in early stage of glaucoma (P < 0.05); in other stages, these parameters had similar to or worse glaucoma diagnostic ability than other GCIPL parameters.

CONCLUSIONS

Macular ganglion cell asymmetry analysis showed good glaucoma diagnostic ability, especially in early-stage glaucoma. However, it has limited usefulness in other stages of glaucoma.