The macula in pediatric glaucoma: quantifying the inner and outer layers via optical coherence tomography automatic segmentation

Chromatic vision and structural assessment in primary congenital glaucoma

Primary congenital glaucoma is a rare disease that occurs in early birth and can lead to low vision. Evaluating affected children is challenging and there is a lack of studies regarding color vision in pediatric glaucoma patients. This cross-sectional study included 21 eyes of 13 children with primary congenital glaucoma who were assessed using the Farnsworth D-15 test to evaluate color vision discrimination and by spectral domain optical coherence tomography to measure retinal fiber layer thickness. Age, visual acuity, cup-to-disc ratio and spherical equivalent data were also collected. Global and sectional circumpapillary and macular retinal fiber layer thicknesses were measured and compared based on color vision test performance. Four eyes (19%) failed the color vision test with diffuse dyschromatopsia patterns. Only age showed statistical significance in color vision test performance. Global and sectional circumpapillary and macular retinal fiber layer thicknesses were similar between the color test outcomes dyschromatopsia and normal. While the color vision test could play a role in assessing children with primary congenital glaucoma, further studies are needed to correlate it with damage to retinal fiber layer thickness.

Development of a Computer System for Automatically Generating a Laser Photocoagulation Plan to Improve the Retinal Coagulation Quality in the Treatment of Diabetic Retinopathy

In this article, the development of a computer system for high-tech medical uses in ophthalmology is proposed. An overview of the main methods and algorithms that formed the basis of the coagulation plan planning system is presented. The system provides the formation of a more effective plan for laser coagulation in comparison with the use of existing coagulation techniques. An analysis of monopulse- and pattern-based laser coagulation techniques in the treatment of diabetic retinopathy has shown that modern treatment methods do not provide the required efficacy of medical laser coagulation procedures, as the laser energy is nonuniformly distributed across the pigment epithelium and may exert an excessive effect on parts of the retina and anatomical elements. The analysis has shown that the efficacy of retinal laser coagulation for the treatment of diabetic retinopathy is determined by the relative position of coagulates and parameters of laser exposure. In the course of the development of the computer system proposed herein, main stages of processing diagnostic data were identified. They are as follows: the allocation of the laser exposure zone, the evaluation of laser pulse parameters that would be safe for the fundus, mapping a coagulation plan in the laser exposure zone, followed by the analysis of the generated plan for predicting the therapeutic effect. In the course of the study, it was found that the developed algorithms for placing coagulates in the area of laser exposure provide a more uniform distribution of laser energy across the pigment epithelium when compared to monopulse- and pattern-based laser coagulation techniques.

The thickness of the outer retina in the macula and circumpapillary area in patients with unilateral advanced glaucoma

PURPOSE

To compare outer macular and retinal thickness in the circumpapillary area in unilateral advanced glaucomatous eyes to the normal or mild glaucomatous fellow eyes.

METHODS

Seventy-eight eyes of 39 patients with unilateral advanced glaucoma (mean deviation (MD) worse than -12.00 dB based on visual field 24-2) were included in this cross-sectional study as the cases. The healthy or mild glaucomatous fellow eyes were enrolled as the control group. All eyes underwent optical coherence tomography of the macula and circumpapillary retina by Topcon DRI Triton (Topcon, Tokyo, Japan). Ganglion cell layer 2+ was considered as the inner retina. Total retinal thickness minus the thickness of the inner retina was considered as the outer retina. Comparison between groups was done by paired-sample sign test. The correlation between structural and functional parameters was evaluated by a partial correlation coefficient.

RESULTS

Seventeen (43.6%), 15 (38.5%), and 7 (17.9%) patients had pseudoexfoliation, primary angle-closure, and primary open-angle glaucoma, respectively. The mean age was 62.69 ± 12.00 years. Thirty-three (84.6%) patients were male. The outer retinal thickness in the circumpapillary area was higher in temporal, superior, and inferior quadrants (p < 0.05). The outer macula in different parafoveal and perifoveal quadrants was also thicker (p < 0.05). Average outer parafoveal thickness in the case group had a significant negative correlation with MD (r = -0.339; p = 0.035).

CONCLUSION

Advanced glaucomatous eyes had a thicker outer retina in the macula and circumpapillary area. There was a significant negative correlation between outer perifoveal thickness and MD.

Changes of Peripapillary Retinal Nerve Fiber Layer in Childhood Glaucoma: A Systematic Review and Meta-Analysis

Objectives: Retinal nerve fiber layer (RNFL) thickness has been detected by numerous studies about alterations and abnormalities in childhood glaucoma, but these studies have yielded inconsistent results about the RNFL thinning region. The investigation of characteristics of RNFL in pediatric patients would contribute to the deep understanding of the neuropathic mechanisms of childhood glaucoma. Thus, the degree of thinning in different quadrants deserves further discussion and exploration. Method: A systematic literature search was conducted using the Cochrane Central Register of Controlled Trials, Medline, Embase, and PubMed databases to identify clinical studies published from inception to April 1, 2021. Results: Ten studies were included in this review with a total of 311 children with glaucoma and 444 in nonglaucomatous controls. The results revealed that average peripapillary RNFL (pRNFL) thickness was attenuated in pediatric patients with glaucoma [weighted mean difference (WMD) = -20.75; 95% CI -27.49 to -14.01; p < 0.00001]. Additionally, pRNFL thickness in eight quadrants (superior, inferior, temporal, nasal, superotemporal, inferotemporal, superonasal, and inferonasal) had different levels of reduction in the pediatric group of glaucoma. Conclusion: This study indicates that eight regions of RNFL thickness show various degrees of thinning in childhood glaucoma. However, caution is required in the interpretation of results due to marked heterogeneity. Future studies, especially larger samples and multicenter, need to confirm our results.

An end-to-end network for segmenting the vasculature of three retinal capillary plexuses from OCT angiographic volumes

The segmentation of en face retinal capillary angiograms from volumetric optical coherence tomographic angiography (OCTA) usually relies on retinal layer segmentation, which is time-consuming and error-prone. In this study, we developed a deep-learning-based method to segment vessels in the superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP) directly from volumetric OCTA data. The method contains a three-dimensional convolutional neural network (CNN) for extracting distinct retinal layers, a custom projection module to generate three vascular plexuses from OCTA data, and three parallel CNNs to segment vasculature. Experimental results on OCTA data from rat eyes demonstrated the feasibility of the proposed method. This end-to-end network has the potential to simplify OCTA data processing on retinal vasculature segmentation. The main contribution of this study is that we propose a custom projection module to connect retinal layer segmentation and vasculature segmentation modules and automatically convert data from three to two dimensions, thus establishing an end-to-end method to segment three retinal capillary plexuses from volumetric OCTA without any human intervention.

Reproducibility of SD-OCT inner macular layer thickness measurements in children with primary congenital glaucoma

PURPOSE

To examine the reproducibility of spectral domain optical coherence tomography (SD-OCT) segmented ganglion cell complex and circumpapillary retinal nerve fiber layer (cpRNFL) measurements in children with primary congenital glaucoma (PCG) in comparison with healthy children.

METHODS

12 children with PCG (G1) and 24 healthy children (G2) were recruited. The following SD-OCT measurements (Spectralis, Heidelberg Engineering) were made in one eye per child: total macular thickness (MT), thicknesses in several subfields and volumes of the three inner macular layers, macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) and cpRNFL thickness. In a single day, an expert operator obtained 3 circumpapillary and 3 macular measurements in each participant to determine intraoperator variability. Intraoperator repeatability was defined by the coefficient of variation (CoV) and intraclass correlation (ICC).

RESULTS

ICC was excellent in both groups for cpRNFL measurements (G1 ICC=0.950 and G2 ICC=0.995) and for MT was excellent in G1 (ICC=0.957) and moderate in G2 (ICC=552). For the inner macular layer measurements, all ICCs were better in PCG group (mRNFL-ICC: 0.915 vs. 0.765; ICC-GCL: 0.584 vs. 0.263 and ICC-IPL: 0.979 vs. 0.742; G1 and G2 respectively). Greater CoV were recorded for macular measurements (from 0.71% to 9.82%) compared to cpRNFL measurements (from 0.52% to 1.50%).

CONCLUSION

In children with PCG, Spectralis SD-OCT showed excellent intrasession repeatability for cpRNFL, MT, mRNFL and IPL measurements and moderated for GCL measurements. For all macular measurements, ICC were higher in children with PCG than healthy children.

Retinal nerve fibre layer thickness measurements in childhood glaucoma: the role of scanning laser polarimetry and optical coherence tomography

Purpose

A central diagnostic tool in adult glaucoma is the peripapillary retinal nerve fibre layer (pRNFL) thickness. It can be assessed by scanning laser polarimetry (SLP) or optical coherence tomography (OCT). However, studies investigating the relevance of pRNFL measurements in children are rare. This study aims to compare the glaucoma diagnosing ability of SLP and OCT pRNFL thickness measurements in a paediatric population.

Methods

This retrospective study included 105 children (glaucoma: 22 (21.0%); healthy glaucoma suspects: 83 (79.0%)) aged 4–18 years, examined with SLP (GDxPro/ECC, Carl Zeiss Meditec) and spectral-domain OCT (SPECTRALIS®, Heidelberg Engineering). The thickness of pRNFL sectors was compared between diseased and healthy participants. Areas under the receiver-operating characteristic curves (AUC) and logistic regression results were used to compare the glaucoma discriminative capacity between SLP and OCT measurements.

Results

Using OCT, pRNFL thickness was decreased in the superior, nasal, and inferior quadrants of glaucoma patients compared to healthy controls (P < 0.001, each). With SLP, such a difference was only observed in the inferior quadrant (P = 0.011). A correlation between glaucoma diagnosis and OCT-measured pRNFL thickness was found in all quadrants (P < 0.001) other than the temporal. With SLP, a correlation was found for the total average thickness (P = 0.037) and inferior quadrant (P = 0.0019). Finally, the AUCs of OCT measurements were markedly higher than those of SLP (e.g., inferior quadrant: OCT 0.83, SLP 0.68).

Conclusion

pRNFL thickness measurements using both OCT and SLP, correlate notably with the presence of glaucoma. In general, the diagnostic performance of pRNFL thickness measurements seems higher for OCT than for SLP. Thus, pRNFL thickness measurements could provide important information, complementing conventional clinical and functional parameters in the diagnostic process of paediatric glaucoma.

The Paediatric Glaucoma Diagnostic Ability of Optical Coherence Tomography: A Comparison of Macular Segmentation and Peripapillary Retinal Nerve Fibre Layer Thickness

Simple Summary

Optical coherence tomography (OCT) is an established ophthalmologic diagnostic tool to visualise vital retinal structures. In glaucoma, it is used to quantify the thickness decrease in the peripapillary retinal nerve fibre layer (pRNFL) and in the macula. While glaucoma management in adults incorporates traditional clinical parameters as well as instrumental methods such as OCT, guidelines for paediatric glaucoma focus on conventional methods. Even though some reports encouraging a broader use of OCT in children are present, its diagnostic potential in this particular population has still not been sufficiently analysed. To address this, the present study compares the glaucoma discriminative ability of OCT measurements of the pRNFL and macular layers in a paediatric population. The results indicate a reduction of the pRNFL and of inner macular layer thickness in glaucoma eyes, as well as a high correlation with the presence of glaucoma. The glaucoma discriminative ability can be maximised combining either all pRNFL sectors or the thickness results of the three innermost macular layers, even though sensitivity remains moderate. In conclusion, the OCT measurements of the pRNFL and macular thickness have a strong ability to diagnose paediatric glaucoma. However, OCT should be used in addition to conventional diagnostic tools rather than as a standalone method.

Abstract

Paediatric glaucoma leads to a decreased thickness of the peripapillary retinal nerve fibre layer (pRNFL) and of the macula. These changes can be precisely quantified using spectral domain-optical coherence tomography (SD-OCT). Despite abundant reports in adults, studies on the diagnostic capacity of macular SD-OCT in paediatric glaucoma are rare. The aim of this study was to compare the glaucoma discriminative ability of pRNFL and macular segment thickness in paediatric glaucoma patients and healthy children. Data of 72 children aged 5–17 years (glaucoma: 19 (26.4%), healthy: 53 (73.6%)) examined with SD-OCT (SPECTRALIS^®, Heidelberg Engineering) were analysed retrospectively. The thickness of pRNFL sectors and of macular segment subfields were compared between diseased and healthy participants. Areas under the receiver-operating characteristic curves (AUC), sensitivity, and specificity from logistic regression were used to evaluate the glaucoma discriminative capacity of single and combined pRNFL and macular segments’ thickness. The results revealed a reduced thickness of the pRNFL and of the three inner macular layers in glaucoma patients, which correlates highly with the presence of glaucoma. The highest glaucoma discriminative ability was observed for the combination of pRNFL sectors or inner macular segments (AUC: 0.83 and 0.85, respectively), although sensitivity remained moderate (both 63% at 95% specificity). In conclusion, while confirmation from investigations in larger cohorts is required, SD-OCT-derived pRNFL and macular thickness measurements seem highly valuable for the diagnosis of paediatric glaucoma.

Overhead Mounted Optical Coherence Tomography in Childhood Glaucoma Evaluation

PRéCIS:: Overhead mounted spectral-domain optical coherence tomography (OCT) enables high-quality imaging of the optic nerve and macula in childhood glaucoma, and is particularly useful when standard tabletop OCT has failed or is not possible.

PURPOSE

Tabletop OCT, integral to adult glaucoma management, can be limited in childhood glaucoma patients because of young age, poor cooperation, and/or technical challenges. To address these imaging difficulties, we determined the feasibility and quality of an overhead mounted unit in childhood glaucoma. Secondary aims included evaluation of peripapillary retinal nerve fiber layer (pRNFL), parafoveal total retinal thickness, and parafoveal ganglion cell complex (GCC) thickness.

MATERIALS AND METHODS

Children and adults with a diagnosis of childhood glaucoma were imaged with an overhead mounted spectral-domain OCT as part of a prospective cross-sectional study. Participants had poor quality or unobtainable tabletop OCT and were scheduled for an examination under anesthesia and/or surgery as part of standard care.

RESULTS

A total of 88 affected eyes in 60 of 65 (92.3%) enrolled patients (mean age, 5.9±5.9 y; range, 0.2 to 24.5) were successfully imaged. The mean image quality for analyzed scans was 22.9±6.0 dB (n=236 images). Mean values for pRNFL (80.5±31.0 µm; n=86), parafoveal total retinal thickness (301.10±39.9 µm; n=79), and parafoveal GCC thickness (96.0±21.6 µm; n=74) were calculated.

CONCLUSIONS

Overhead mounted OCT allowed high-quality image acquisition and analysis in childhood glaucoma patients unable to be imaged with the tabletop counterpart, presenting an opportunity for improved clinical management and study of childhood glaucoma-related pathophysiology. pRNFL, parafoveal total retinal thickness, and parafoveal GCC thickness were decreased for affected eyes of children under 6 years of age compared with age-matched controls from a companion normative study.

Reproducibility of macular retinal nerve fiber layer and ganglion cell layer thickness measurements in a healthy pediatric population

PURPOSE

To evaluate the reproducibility of Spectralis spectral domain-OCT segmented ganglion cell layer (GCL) and macular retinal nerve fiber layer (mRNFL) measurements in a healthy children population.

METHODS

An observational, cross-sectional study was carried out on 79 children to measure the intraobserver reproducibility and the repeatability between a novel and an experienced operator of the segmented macular GCL and mRNFL. Interobserver and intraobserver reproducibility were defined by the intraclass correlation coefficient (ICC) and coefficients of variation (COV). Kruskal-Wallis test was used to determine statistical significance in the COV of three age groups children (younger than 6 years, between 6 and 12, and older than 12 years old).

RESULTS

The results from the intraoperator GCL thickness analysis were highly reproducible (COV < 6%) and reliable (ICCs > 0.81). When the measurements were compared between a novel and an experienced examiner lower ICCs and higher COV were found. COVs ranged from 1.85% (total volume area) to 5.57% at the central ETDRS subfield while the ICC vary from 0.632 (outer inferior) to 0.832 (inner inferior). The repeatability and reproducibility of the mRNFL thickness were lower, with ICCs ranging from 0.428 to 0.872 in the interobserver analysis and from 0.897 to 0.346 in the interobserver one.

CONCLUSION

In the present study, we establish substantial reliability of the GCL thickness in children with Spectralis^® SD-OCT in all the sectors, albeit lower than the reported in the literature with other SD-OCTs and in adults. The reproducibility and repeatability of the mRNFL were significantly lower. We were unable to find consistent statistical significant differences between the COV of the three age groups.

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

PURPOSE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.].

Ganglion Cell Complex Analysis in Glaucoma Patients: What Can It Tell Us?

Glaucoma is a group of optic neuropathies characterized by a progressive degeneration of retina ganglion cells (RGCs) and their axons that precedes functional changes detected on the visual field. The macular ganglion cell complex (GCC), available in commercial Fourier-domain optical coherence tomography, allows the quantification of the innermost retinal layers that are potentially involved in the glaucomatous damage, including the retinal nerve fiber (RNFL), ganglion cell and inner plexiform layers. The average GCC thickness and its related parameters represent a reliable biomarker in detecting preperimetric glaucomatous damage. The most accurate GCC parameters are represented by average and inferior GCC thicknesses, and they can be associated with progressive visual field loss. Although the diagnostic accuracy increases with more severe glaucomatous damage and higher signal strength values, it is not affected by increasing axial length, resulting in a more accurate discrimination of glaucomatous damage in myopic eyes with respect to the traditional RNFL thickness. The analysis of the structure-function relationship revealed a good agreement between the loss in retinal sensitivity and GCC thickness. The use of a 10-2° visual field grid, adjusted for the anatomical RGCs displacement, describes more accurately the relationship between RGCs thickness and visual field sensitivity loss.

Optical Coherence Tomography Normative Peripapillary Retinal Nerve Fiber Layer and Macular Data in Children 0-5 Years of Age

PURPOSE

To determine reference values for the peripapillary retinal nerve fiber layer (pRNFL) and macula in children 0-5 years of age.

DESIGN

Prospective cross-sectional study.

METHODS

This study was set in a single large academic pediatric ophthalmology practice. Healthy, full-term children 0 to <6 years of age presenting for surgery under general anesthesia were prospectively recruited for participation. Excluded were children with systemic neurologic disease, optic nerve or retinal disease (even if unilateral) or any bilateral ocular disease process, and eyes with amblyopia, ocular disease, or spherical equivalent refractive error outside of -3.00 to +8.00 diopters. Following general anesthesia, OCT scans of the optic nerve and retina were acquired using an HRA+OCT Spectralis with Flex module (Heidelberg Engineering). Automated segmentation of the pRNFL and retinal layers was followed by manual correction.

RESULTS

Data were obtained from normal eyes of 57 participants (mean age 2.28 ± 1.50 years). Mean global pRNFL thickness was 107.6 ± 10.3 μm. Mean global pRNFL thickness was not dependent on age but showed a negative relationship with axial length (P = .01). The mean total macular volume was 8.56 ± 0.259 mm³ (n = 38). No relationship was found between total macular volume and age. Ganglion cell layer, ganglion cell complex, and inner nuclear layer volumes showed an inverse relationship with age while the photoreceptor layers showed a logarithmic increase with age.

CONCLUSIONS

Global pRNFL thickness measurements remain stable over time. Macular volume and thickness values of segmented retinal layers reflect the development of the macula with age.

Handheld Optical Coherence Tomography Normative Inner Retinal Layer Measurements for Children <5 Years of Age

PURPOSE

Measurements of the ganglion cell complex (GCC), comprising the retinal nerve fiber (RNFL), ganglion cell, and inner plexiform layers, can be correlated with vision loss caused by optic nerve disease. Handheld optical coherence tomography (HH-OCT) can be used with sedation in children who are not amenable to traditional imaging. We report GCC and RNFL measurements in normal children using HH-OCT.

DESIGN

Prospective observational study of normal children ≤5 years of age.

METHODS

Healthy, full-term children ≤5 years of age undergoing sedation or anesthesia were enrolled. Exclusion criteria included prematurity and pre-existing neurologic, genetic, metabolic, or intraocular pathology. Demographic data, axial length (Master-Vu Sonomed Escalon, Lake Success, New York, USA), and HH-OCT macular and optic nerve volume scans at 0° (Bioptigen, Inc., Morrisville, North Carolina, USA) were obtained. Retinal segmentation was completed with DOCTRAP software, creating average volume thickness maps.

RESULTS

Sixty-seven children (67 eyes, 31 males ranging in age from 3.4-70.9 months) were enrolled. Average axial length was 21.2 ± 1.0 mm with mean spherical equivalent +1.49 ± 1.34 diopters (range -2.25 to 4.25). Average GCC volume for the total retina was 0.28 ± 0.04 mm³. Forty-seven of these eyes had RNFL analysis. Average RNFL thickness of the papillomacular bundle was 38.2 ± 9.5 μm. There was no correlation between GCC volume, RNFL thickness, patient age, or axial length.

CONCLUSION

Average GCC volume and RNFL thickness was stable from 6 months to 5 years of age. This study provides normative data for GCC and RNFL obtained by HH-OCT in healthy eyes of young children, to serve in evaluating those with optic neuropathies.

Detection and characterisation of optic nerve and retinal changes in primary congenital glaucoma using hand-held optical coherence tomography

Objective

To investigate (1) the feasibility of scanning the optic nerve (ON) and central retina with hand-held optical coherence tomography (HH-OCT) without sedation or anaesthesia in primary congenital glaucoma (PCG), (2) the characteristics of ON changes in comparison with adult primary open-angle glaucoma (POAG) in comparison with matched controls, (3) the sensitivity and specificity of ON parameters for diagnosis, and (4) changes of foveal morphology.

Methods and analysis

HH-OCT (Envisu 2300; Leica Microsystems) was used to investigate ON and foveal morphology of 20 children with PCG (mean age 4.64±2.79) and 10 adult patients with POAG (mean age 66.8±6.94), and compared with age-matched, gender-matched and ethnicity-matched healthy controls without sedation or anaesthesia.

Results

HH-OCT yielded useful data in 20 out of 24 young children with PCG. Patients with PCG had significantly deeper cup changes than patients with POAG (vs respective age-matched controls, p=0.014). ON changes in PCG are characterised by significant increase in cup depth (165%), increased cup diameter (159%) and reduction in rim area (36.4%) as compared with controls with high sensitivity (81.5, 74.1% and 88.9%, respectively) and specificity (85.0, 80.0% and 75.0%, respectively). Patients with PCG have a significantly smaller width of the macula pit (p<0.001) with non-detectable external limiting membrane.

Conclusion

HH-OCT has the potential to be a useful tool in glaucoma management for young children. We have demonstrated the use of HH-OCT in confirming a diagnosis of glaucoma within the studied cohort and found changes in disc morphology which characterise differently in PCG from POAG.

Outer retinal layer thickness in patients with glaucoma with horizontal hemifield visual field defects

BACKGROUND/AIMS

To determine the effect of glaucoma on outer retinal layer thickness in eyes with horizontal hemifield visual field (VF) defects.

METHODS

We conducted a cross-sectional study in glaucomatous eyes with repeatable (in three or examinations) horizontal hemifield VF (programme 24-2) defect defined as: all five nasal VF locations immediately either above or below the horizontal midline abnormal in the pattern deviation plot with p<0.5%; no mirror-image adjacent 5 VF locations abnormal in the pattern deviation plot and no non-edge VF locations in the non-affected hemifield abnormal in the pattern deviation plot with p<1%. We used optical coherence tomography to measure thickness of each retinal layer in the temporal macula (12° horizontally and 24° vertically) and computed the absolute (µm) and relative (%) intraindividual asymmetry between the perimetrically normal and abnormal hemimacula.

RESULTS

We included 10 eyes of 8 patients with median age of 67 years and median VF mean deviation of -8.85 dB. The nerve fibre, ganglion cell and inner plexiform layers were significantly thinner in the perimetrically abnormal hemimacula (median asymmetry of -6.4, -11.5 and -3.8 µm, (corresponding to -27.7, -40.5 and -15.7 %), respectively, all p≤0.01). The inner nuclear layer was slightly thicker in the perimetrically abnormal hemimacula (median asymmetry of 1.3 µm (5.0 %), p=0.01). The outer plexiform, outer nuclear and photoreceptor layers asymmetry values were negligible.

CONCLUSION

Our study showed no evidence that glaucoma has an effect on the outer retinal layer thickness. In contrast, a large impact was observed in inner layer thickness.

Retinal Parameters as Compared with Head Circumference, Height, Weight, and Body Mass Index in Children in Kenya and Bhutan

The retina shares embryological derivation with the brain and may provide a new measurement of overall growth status, especially useful in resource-limited settings. Optical coherence tomography (OCT) provides detailed quantification of retinal structures. We enrolled community-dwelling children ages 3–11 years old in Siaya, Kenya and Thimphu, Bhutan in 2016. We measured head circumference (age < 5 years only), height, and weight, and standardized these by age and gender. Research staff performed OCT (iScan; Optovue, Inc., Fremont, CA), measuring the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) thicknesses. A neuro-ophthalmologist performed quality control for centration, motion artifact, and algorithm-derived quality scores. Generalized estimating equations were used to determine the relationship between anthropometric and retinal measurements. Two hundred and fifty-eight children (139 females, average age 6.4 years) successfully completed at least one retinal scan, totaling 1,048 scans. Nine hundred and twenty-two scans (88.0%) were deemed usable. Fifty-three of the 258 children (20.5%) were able to complete all six scans. Kenyan children had a thinner average GCC (P < 0.001) than Bhutanese children after adjustment for age and gender, but not RNFL (P = 0.70). In models adjusting for age, gender, and study location, none of standardized height, weight, and body mass index (BMI) were statistically significantly associated with RNFL or GCC. We determined that OCT is feasible in some children in resource-limited settings, particularly those > 4 years old, using the iScan device. We found no evidence for GCC or RNFL as a proxy for height-, weight-, or BMI-for-age. The variation in mean GCC thickness in Asian versus African children warrants further investigation.

Diagnostic capacity of SD-OCT segmented ganglion cell complex versus retinal nerve fiber layer analysis for congenital glaucoma

PURPOSE

To compare the diagnostic performance of circumpapillary retinal nerve fiber layer (cpRNFL) analysis versus segmented ganglion cell complex analysis both by spectral-domain optical coherence tomography (SD-OCT) in children with primary congenital glaucoma (PCG).

METHODS

Participants were 40 children diagnosed with PCG and 60 healthy children. Ophthalmological data collected (for one eye per child) were cup-disc ratio (C/D) and axial length (AL). SD-OCT with automated segmentation was used to measure the thicknesses and volumes of the macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL). For the cpRNFL measurements conventional S-D OCT software was used and the capacity of each method to discriminate between normal and glaucomatous eyes was compared.

RESULTS

Mean age was 11.20 ± 3.94 years for the glaucoma patients and 10.90 ± 2.46 years for controls (p = 0.64). All measurements were reduced (thinner) in the glaucoma group, significantly so for: cpRNFL, GCL, IPL and outer-superior and outer-inferior quadrant mRNFL. According to their areas under the receiver operating characteristics curve (AUC), temporal superior cpRNFL (0.869) and outer superior GCL (0.840), IPL (0.799), and mRNFL (0.767) showed the better diagnostic capacity. No differences were observed in AUCs for the most discriminatory cpRNFL and macular measurements.

CONCLUSION

Segmented macular layer analysis shows a good capacity to discriminate between normal and glaucomatous eyes; which is comparable to that of cpRNFL analysis in children with PCG.