Advantages and Pitfalls of the Use of Optical Coherence Tomography for Papilledema.

PURPOSE OF REVIEW: Papilledema refers to optic disc swelling caused by raised intracranial pressure. This syndrome arises from numerous potential causes, which may pose varying degrees of threat to patients. Manifestations of papilledema range from mild to severe, and early diagnosis is important to prevent vision loss and other deleterious outcomes. The purpose of this review is to highlight the role of optical coherence tomography (OCT) in the diagnosis and management of syndromes of raised intracranial pressure associated with papilledema. RECENT FINDINGS: Ophthalmoscopy is an unreliable skill for many clinicians. Optical coherence tomography is a non-invasive ocular imaging technique which may fill a current care gap, by facilitating detection of papilledema for those who cannot perform a detailed fundus examination. Optical coherence tomography may help confirm the presence of papilledema, by detecting subclinical peripapillary retinal nerve fiber layer (pRNFL) thickening that might otherwise be missed with ophthalmoscopy. Enhanced depth imaging (EDI) and swept source OCT techniques may identify optic disc drusen as cause of pseudo-papilledema. Macular ganglion cell inner plexiform layer (mGCIPL) values may provide early signs of neuroaxonal injury in patients with papilledema and inform management for patients with syndromes of raised intracranial pressure. There are well-established advantages and disadvantages of OCT that need to be fully understood to best utilize this method for the detection of papilledema. Overall, OCT may complement other existing tools by facilitating detection of papilledema and tracking response to therapies.  Moving forward, OCT findings may be included in deep learning models to diagnose papilledema.

Analysis of retinal and choroidal microvascular changes using optical coherence tomography and optical coherence tomography angiography in patients with acute leukemia.

PURPOSE: Although leukemic retinopathy accounts for 80% of ocular complications in acute leukemia, its pathogenesis remains unclear. To evaluate changes in retinal and choroicapillaris and structural parameters in patients with acute leukemia, we analyzed the correlation between vascular perfusion metrics and laboratory parameters and assessed the changes after hematopoietic stem cell transplantation (HSCT). METHODS: Herein, 104 eyes of 52 patients aged 18 and above with acute leukemia were enrolled. 80 eyes of 40 healthy patients were recruited as control participants. All participants underwent optical coherence tomography (OCT) and OCT angiography (OCTA) at baseline. RESULTS: Patients with acute leukemia had a significantly thicker ganglion cell-inner plexiform layer (GCIPL) and lower circularity index than the control participants. Post-HSCT perfusion metrics did not differ significantly, but parafoveal thickness decreased significantly. During the active phase of acute leukemia, lower platelet levels were associated with significant GCIPL thickening and increased foveal avascular zone and perimeter. D-dimer levels positively correlated with GCIPL thickness. CONCLUSION: Patients with acute leukemia had subclinical retinal microvascular deficits on OCTA and GCIPL thickening on OCT, possibly associated with bone marrow function. GCIPL thickness may indicate acute ischemia in such patients. Further studies must elucidate their clinical and prognostic significance.

Characterisation of the normal human ganglion cell-inner plexiform layer using widefield optical coherence tomography.

PURPOSE: To describe variations in ganglion cell-inner plexiform layer (GCIPL) thickness in a healthy cohort from widefield optical coherence tomography (OCT) scans. METHODS: Widefield OCT scans spanning 55° × 45° were acquired from 470 healthy eyes. The GCIPL was automatically segmented using deep learning methods. Thickness measurements were extracted after correction for warpage and retinal tilt. Multiple linear regression analysis was applied to discern trends between global GCIPL thickness and age, axial length and sex. To further characterise age-related change, hierarchical and two-step cluster algorithms were applied to identify locations sharing similar ageing properties, and rates of change were quantified using regression analyses with data pooled by cluster analysis outcomes. RESULTS: Declines in widefield GCIPL thickness with age, increasing axial length and female sex were observed (parameter estimates -0.053, -0.436 and -0.464, p-values <0.001, <0.001 and 0.02, respectively). Cluster analyses revealed concentric, slightly nasally displaced, horseshoe patterns of age-related change in the GCIPL, with up to four statistically distinct clusters outside the macula. Linear regression analyses revealed significant ageing decline in GCIPL thickness across all clusters, with faster rates of change observed at central locations when expressed as absolute (slope = -0.19 centrally vs. -0.04 to -0.12 peripherally) and percentage rates of change (slope = -0.001 centrally vs. -0.0005 peripherally). CONCLUSIONS: Normative variations in GCIPL thickness from widefield OCT with age, axial length and sex were noted, highlighting factors worth considering in further developments. Widefield OCT has promising potential to facilitate quantitative detection of abnormal GCIPL outside standard fields of view.

Retinal nerve fiber layer and ganglion cell complex thickness in diabetic smokers without diabetic retinopathy.

PURPOSE: To compare the thickness of the retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GC-IPL) in smoker and nonsmoker diabetics without diabetic retinopathy. MATERIALS AND METHODS: Patients with diabetes were divided into two groups according to their smoking status: Group 1 consisted of 38 smoker diabetics who had chronically smoked more than 20 cigarettes per day for more than five years; Group 2 consisted of 38 nonsmoker diabetics. After a detailed ophthalmologic examination, the mean and regional (superior, supratemporal, inferior, inferotemporal, temporal, nasal, superonasal, and inferonasal) RNFL and GC-IPL thicknesses were measured with spectral-domain optic coherence tomography (SD-OCT) and compared between groups. RESULTS: The mean age was 54.7 ± 10.5 and 51.2 ± 9.7 years in the smoker and nonsmoker groups, respectively (p = 0.14). Gender, duration of diabetes, and the mean axial length were similar between groups (p:0.43, p:0.54, p: 0.52, respectively). Mean RNFL thickness was 89.1 ± 8.0 µm in the smoker group and 93.4 ± 7.0 µm in the nonsmoker group, and it was significantly thinner in the smoker group (p = 0.01). The temporal RNFL thickness in the smoker group was thinner than in the nonsmoker group (p = 0.02). There was no difference in superior, inferior, and nasal RNFL thicknesses between the groups (p = 0.31, p = 0.12, p = 0.39, respectively). The mean macular GC-IPL thickness of the smoker and nonsmoker groups was 78.53 ± 15.74 µm and 83.08 ± 5.85 µm, respectively (p = 0.09). Superior, superonasal, inferonasal, inferior, inferotemporal, and superotemporal quadrant GC-IPL thicknesses were similar between the groups (p = 0.07, p = 0.60, p = 0.55, p = 0.77, p = 0.71, p = 0.08, respectively). The groups showed no difference in minimum GC-IPL thickness (p = 0.43). There was a significant negative correlation between smoking exposure and mean, inferior quadrant RNFL thicknesses in the smoker group (p = 0.04, r= -0.32, and p = 0.01, r= -0.39, respectively). CONCLUSION: Mean RNFL thickness was significantly thinner in smoker diabetics. Although not statistically significant, especially mean, superior, and superotemporal GC-IPL was thinner in smoker diabetics. The results suggest a potential association between the coexistence of diabetes and smoking with alterations in RNFL and GC-IPL thickness.

Quantitatively Evaluating the Relationships between Insulin Resistance and Retinal Neurodegeneration with Optical Coherence Tomography in Early Type 2 Diabetes Mellitus.

INTRODUCTION: The aim of this study was to quantitatively assess retinal neurodegenerative changes with optical coherence tomography (Cirrus HD-OCT) in type 2 diabetes mellitus (T2DM) patients without diabetic retinopathy (DR) and evaluate their relationships with insulin resistance (IR) and associated systemic indicators. METHODS: 102 T2DM patients without DR and 48 healthy controls were included in this observational cross-sectional study. The OCT parameters of macular retinal thickness (MRT) and ganglion cell-inner plexiform layer (GCIPL) thicknesses were evaluated between diabetic and normal eyes. The receiver operating characteristics (ROC) curve was generated to evaluate the discrimination power of early diabetes. Correlation and multiple regression analysis were performed between ophthalmological parameters and T2DM-related demographic and anthropometric variables, and serum biomarkers and homeostasis model assessment of insulin resistance (HOMA-IR) scores. RESULTS: MRT and GCIPL thicknesses showed significant thinning in patients, especially in inferotemporal area. High body mass index (BMI) correlated with decreased GCIPL thicknesses and elevated intraocular pressure (IOP). A negative correlation between waist-to-hip circumference ratio (WHR) and GCIPL thicknesses was also found. High-density lipoprotein (HDL) and fasting C-peptide (CP0) were associated with GCIPL thickness but only in inferotemporal region (r = 0.20, p = 0.04; r = -0.20, p = 0.05, respectively). Multiple regression analysis showed that increased HOMA-IR scores independently predicted both average (ß = -0.30, p = 0.05) and inferotemporal (ß = -0.34, p = 0.03) GCIPL thinning. CONCLUSION: Retinal thinning in early T2DM was associated with obesity-related metabolic disorders. IR as an independent risk factor for retinal neurodegeneration may increase the risk of developing glaucoma.

Brain-derived neurotrophic factor levels and macular ganglion cell-inner plexiform layer thickness in macular telangiectasia type 2.

PURPOSE: To determine brain-derived neurotrophic factor (BDNF) levels in the serum and aqueous humor (AH) and assess the relationship between BDNF levels and the thickness of the macular ganglion cell-inner plexiform layer (GCIPL) in macular telangiectasia type 2 (MacTel). METHODS: This study included 25 patients with MacTel (MacTel group) and 25 control subjects (control group). The levels of BDNF in the serum and AH were tested using an enzyme-binding immunosorbent assay. GCIPL thickness was measured by segmentation analysis using optical coherence tomography (OCT). RESULTS: There was no significant difference in the mean serum BDNF levels between the MacTel and control groups (p = 0.145). The average BDNF level in the AH was significantly lower than that in the control group (p = 0.026). OCT segmentation analyses revealed that the minimum GCIPL thickness was significantly lower in the MacTel group than in the control group (p = 0.039). In the correlation analysis of BDNF levels with GCIPL thickness, significant correlations existed between the BDNF level of the AH and minimum GCIPL thickness in the MacTel group. CONCLUSION: The concentration of BDNF in the AH was decreased in the MacTel group, and this reduction was related to the minimum GCIPL thickness. The low BDNF levels detected in the MacTel group may have resulted in thinning of the GCIPL due to the loss of retinal ganglion cells.

Spatial positional relationship between macular superficial vessel density and ganglion cell-inner plexiform layer thickness in primary angle closure glaucoma.

PURPOSE: To evaluate the spatial relationship between macular superficial vessel density (SVD) and macular ganglion cell-inner plexiform layer (GCIPL) thickness in primary angle closure glaucoma (PACG), and to investigate diagnostic abilities of macular SVD and foveal avascular zone (FAZ) parameters. METHODS: This was a cross-sectional study on 38 PACG patients (38 eyes) and 25 healthy subjects (25 eyes). Macular region was imaged using a 1050-nm-wavelength swept-source optical coherence tomography (OCT) angiography (OCTA) system (DRI OCT Triton, TOPCON). Vessel density of the macular region was quantified by ImageJ software. The peripapillary retinal nerve fiber layer (pRNFL) thicknesses and macular GCIPL thickness were obtained by swept-source OCT. Pearson correlation analysis was used to evaluate the spatial positional relationship between macular SVD and macular GCIPL thickness. At the same time, the correlation between macular SVD and pRNFL thickness was evaluated. Areas under the receiver operating characteristics curves (AUCs) of OCT, OCTA and FAZ measurement metrics were calculated to assess the diagnostic ability for glaucoma. RESULTS: Macular GCIPL thickness had a moderate correlation with the macular SVD in the inferonasal sector (r = 0.426, P = 0.008). In addition, there was a strong correlation between inferonasal sector of macular vessel density and 5,6,7,8 clock-hour regions of the pRNFL thicknesses (all r > 0.5). Inferoinferior sector of macular SVD and 6,7 clock-hour regions of pRNFL thicknesses also had strong correlation (all r > 0.5). The AUCs of macular SVD ranged between 0.61 (superonasal sector) and 0.76 (inferoinferior sector). The FAZ circularity index showed the highest diagnostic power (AUC = 0.94;95% CI, 0.85-0.99), followed by superotemporal sector of macular GCIPL thicknesses (0.93;95% CI,0.83-0.98). CONCLUSIONS: Sector of macular SVD not only had a spatial positional correlation with corresponding macular GCIPL thickness, but also with clock-hour regional pRNFL thicknesses in PACG eyes. FAZ circulation index might be a useful diagnostic parameter.

Change of ocular parameters in children with large cup-to-disc ratio and interocular cup-to-disc ratio asymmetry.

BACKGROUND: Enlarged optic disc cupping and interocular cup-to-disc ratio (CDR) asymmetry are often important indicators of glaucoma. Clinically, we occasionally encounter children with large CDR and interocular CDR asymmetry during vision screening. This study aimed to report longitudinal change of ocular parameters in children with large cup-to-disc ratio (CDR) and interocular CDR asymmetry. METHODS: This was a retrospective, observational case series of 160 eyes of 160 children with large CDR who visited a tertiary eye center from January 2010 to June 2016. Average CDR ≥ 0.6 were considered large CDR values, and CDR asymmetry was defined as an interocular difference ratio value greater than 0.2. All included patients showed interocular pressure (IOP) < 21 mmHg at least three ophthalmic examinations conducted at total intervals of at least 30 months. RESULTS: The mean age of children included in the study was 7.14 ± 2.42 years, with a follow-up period of 54.46 ± 19.82 months. Changes in refractive error and axial length were significantly different between initial and final examination (p < 0.001). However, optic nerve head (ONH) analysis and retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) thicknesses were not significantly different between initial and final examination. In interocular comparisons of patients with CDR asymmetry, changes of refractive error, axial length, ONH analysis, and RNFL and mGCIPL thickness were not significantly different between the two eyes. CONCLUSIONS: There were no significant differences in the changes of ONH analysis, and RNFL and mGCIPL thicknesses in children with large CDR, or those with interocular CDR asymmetry over the study period. Our results provide helpful information for the establishment of guidelines for managing children with large CDR and interocular CDR asymmetry.

May ganglion cell complex analysis be a marker for glaucoma susceptibility in unilateral Fuchs' uveitis syndrome?

PURPOSE: To compare retinal nerve fiber layer (RNFL) thickness and ganglion cell-inner plexiform layer thickness (GCIPLT) in the affected eyes to fellow unaffected eyes of patients with unilateral Fuchs' uveitis syndrome (FUS) and analyze their change over time. METHODS: Twenty seven unilateral FUS patients who did not have concomitant systemic or ocular disease were retrospectively enrolled. Central macular thickness (CMT), RNFL thickness, and GCIPLT measurements were evaluated. Data was analyzed using the non-parametric Brunner-Langer model (LD-F2 design) and Wilcoxon signed-rank test. RESULTS: The mean age of the patients was 40.2 ± 10.2 years. The median disease duration was 11 (2-62) months. The median best-corrected visual acuity (BCVA) of the affected eyes and the fellow eyes was 0.22 (0.00-2.50) vs. 0.00 (0.0-0.10) logMAR at the initial visit and 0.05 (0.00-2.50) vs. 0.00 (0.0-0.30) logMAR at the final visit. The change in BCVA was found significant in the affected eyes, but not in the fellow eyes (p < 0.001 and p = 0.287, respectively). The median CMT in the affected eyes at the final visit was not statistically different from the value at the initial visit (255 (157-306) vs. 245 (140-310) µm, p = 0.256). The change in RNFL thickness over time in the affected eyes was similar to the fellow unaffected eyes of the patients with unilateral FUS at all quadrants, with non-significant time and group effects (p > 0.05). However, median GCIPLT in all quadrants (except superonasal) in the affected eyes was statistically lower than the fellow eyes at the initial and final visits (p < 0.05). The most affected quadrant of the ganglion cell complex was inferonasal in the involved eyes (79 (42-97) vs. 75 (43-87) µm) at initial and final visits (p = 0.033 for time effect and p < 0.001 for group effect, respectively). CONCLUSION: Median CMT and RNFL thickness did not change during follow-up in the affected eyes of patients with unilateral FUS. Median GCIPLT in the affected eyes declined over time in all quadrants. Ganglion cell loss was also most prominent in the inferonasal quadrant in the affected eyes. FUS patients should be followed up long-term in terms of ganglion cell loss, especially in the inferonasal quadrant.

Determinants of macular ganglion cell-inner plexiform layer thickness in normal Chinese adults.

BACKGROUND: Demographic, systemic and ocular factors may impact macular ganglion cell-inner plexiform layer (GCIPL) thickness measurements. This study aimed to investigate the influences of multiple potential determinants of macular GCIPL thickness in normal Chinese adults. METHODS: This was a retrospective study conducted on 225 normal eyes from 225 healthy Chinese adults. GCIPL thickness were obtained using Cirrus high-definition optical coherence tomography (OCT). The age, gender, laterality, spherical equivalent (SE) refractive error, intraocular pressure (IOP), axial length (AL), central cornea thickness (CCT), circumpapillary retinal nerve fibre layer (pRNFL) thickness and OCT signal strength were recorded and their respective effect on GCIPL thickness parameters were evaluated. RESULTS: The mean (± SD) average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal GCIPL thickness was 84.56 ± 5.36, 81.32 ± 5.58, 83.08 ± 5.37, 85.70 ± 5.95, 87.15 ± 6.26, 85.07 ± 6.11, 82.46 ± 5.76, and 83.88 ± 5.59 µm, respectively. Determinants of thinner GCIPL thickness were older age (P = 0.001-0.117; effects enhanced if age over 40 years), thinner pRNFL (all P < 0.001), and weaker signal strength (all P < 0.001). No significant difference was found between males and females (P = 0.069-0.842), and between right eyes and the left eyes (P = 0.160-0.875) except that of superonasal GCIPL thickness (P < 0.001). There was no significant correlation between GCIPL thickness and SE, IOP, CCT, and AL (P = 0.135-0.968). CONCLUSIONS: Individual determinants associated with thinner GCIPL thickness were older age (particularly over 40 years of age), thinner pRNFL, and weaker OCT signal strength. This is relevant in comprehensively understanding the normative data and differentiating normal aging from abnormalities.

Analysis of structural injury patterns in peripapillary retinal nerve fibre layer and retinal ganglion cell layer in ethambutol-induced optic neuropathy.

BACKGROUND: We investigated structural injury patterns in the peripapillary retinal nerve fibre layer (p-RNFL) and ganglion cell inner plexiform layer (GCIPL) caused by ethambutol treatment. METHODS: Sixty-four patients undergoing ethambutol treatment at Zhejiang Chinese Medicine and Western Medicine Integrated Hospital were recruited. Fourteen (14) exhibited visual dysfunction (abnormal group), and the remaining 50 had no visual dysfunction (subclinical group). The thickness of the p-RNFL, total macular retina layer and GCIPL were measured using Cirrus-HD Optical coherence tomography (Cirrus-HD OCT, Cirrus high-definition optical coherence tomography), and compared with 60 healthy, age-matched controls. RESULTS: The p-RNFL thickness was similar in both subclinical and control groups. When compared with the control group, p-RNFL thickness in the abnormal group was significantly increased in the inferior and superior quadrants (GEE, P = 0.040, P = 0.010 respectively). In contrast with the subclinical group, p-RNFL thickness in the inferior quadrant was increased in the abnormal group (GEE, P = 0.047). The GCIPL thickness in the inferonasal and inferior sectors was significantly deceased in the subclinical group when compared with controls (GEE, P = 0.028, P = 0.047, respectively). The average and minimum value of GCIPL thickness, and thickness in the superonasal, inferior, inferotemporal, superotemporal and superior sectors were significantly decreased in the abnormal group when compared with controls (GEE, P = 0.016, P = 0.001, P = 0.028, P = 0.010, P = 0.012, P = 0.015, P = 0.010, respectively). The cube average macular thickness (CAMT) in the abnormal group was significantly thinner than controls (GEE, P = 0.027). CONCLUSIONS: GCIPL measurements using Cirrus-HD OCT detected retinal ganglion cell layer loss following ethambutol treatment, before visual dysfunction occurred.

Associations of Ganglion Cell-Inner Plexiform Layer and Optic Nerve Head Parameters with Visual Field Sensitivity in Advanced Glaucoma.

PURPOSE: To evaluate the associations of optical coherence tomography (OCT)-derived macular ganglion cell-inner plexiform layer thickness (mGCIPLT), circumpapillary retinal nerve fiber layer thickness (cpRNFLT), and optic nerve head (ONH) parameters with visual field (VF) sensitivity in advanced glaucoma. METHODS: In this cross-sectional study, 102 eyes from 102 patients with advanced glaucoma (defined as a 24-2 VF mean deviation (MD) of ≤-12 dB) were included. mGCIPLT, cpRNFLT, and ONH parameters (including the rim area, average cup-to-disc [C:D] ratio, and vertical C:D ratio) were measured using Cirrus high-definition OCT, and 24-2 and 10-2 VF sensitivity tests were performed using standard automated perimetry. Pearson correlations and linear models were used to analyze relationships between OCT-derived parameters and VF parameters. RESULTS: The mGCIPLT and rim area were significantly positively correlated with the 24-2 VF MD, 24-2 VF pattern standard deviation, 24-2 VF visual field index, and 10-2 VF MD, but cpRNFLT was not significantly correlated with VF parameters. In addition, the average and vertical C:D ratios were significantly negatively correlated with VF parameters. The mGCIPLT and rim area were significantly positively correlated with the 10-2 VF MD (r ranging between 0.542 and 0.621, p < 0.001), while the average and vertical C:D ratios were significantly negatively correlated with the 10-2 VF MD (r = -0.537, p < 0.001, and r = -0.428, p < 0.001, respectively). Each 1-µm change in the average mGCIPLT was associated with an approximately 0.368-dB change in the 24-2 VF MD and 0.677-dB change in the 10-2 VF MD (R2 = 0.268, p < 0.001, and R2 = 0.385, p < 0.001, respectively). The 10-2 VF MD showed a significantly stronger association with inferonasal mGCIPLT than did the 24-2 VF MD in advanced glaucoma (p = 0.007). CONCLUSIONS: mGCIPLT and ONH parameters were associated with the severity of VF damage and reflected functional damage better than cpRNFLT in advanced glaucoma. Our results suggested that structural measurements of mGCIPLT and ONH parameters and functional measurement of the 10-2 VF may be useful for monitoring progression in advanced glaucoma.

Retinal thinning and brain atrophy in early MS and CIS.

BACKGROUND: Optical coherence tomography (OCT) could be complementary to magnetic resonance imaging (MRI) of the brain in monitoring course of multiple sclerosis (MS) and clinically isolated syndrome (CIS). Thinning of neurons in ganglion cell-inner plexiform layer (GCIPL) measured by OCT is assumed to be associated with brain atrophy. OBJECTIVES: To evaluate association of GCIPL with brain parameters detected by quantitative MRI (qMRI) and MR-spectroscopy (MRS) in early MS and CIS. METHODS: Seventeen newly diagnosed MS and 18 CIS patients were prospectively included. The patients were assessed at baseline as well as at 1 year follow-up by OCT, qMRI and MRS. Brain parenchymal and myelin volumes (BPV, MYV respectively) and the corresponding fractions (BPF, MYF) were measured with qMRI. Metabolites including myo-inositol (myo-Ins) were measured in the normal-appearing white matter (NAWM) using MRS. T-tests and ANOVA were used to analyze group differences, and linear regression models to evaluate association of GCIPL with BPV, MYV and myo-Ins after correlation analysis. RESULTS: Disease activity reflected by lesions on MRI and presence of CSF oligoclonal IgG bands were more prominent in MS compared to CIS. GCIPL, BPV, MYV, BPF and MYF were reduced, while concentration of myo-Ins was increased in MS compared to CIS. Follow-up showed consistency of thinner GCIPL in MS compared to CIS. GCIPL thinning correlated with reduced BPV and MYV (P < .05 for both), but with increased myo-Ins (P < .01). CONCLUSIONS: Significant GCIPL thinning occurs in early MS and is associated with enhanced brain inflammation and atrophy.

Causes of ganglion cell-inner plexiform layer thinning in myopic eyes.

PURPOSE: The present study aimed to determine the main cause of ganglion cell-inner plexiform layer (GCIPL) thinning in long myopic eyes. METHODS: Optical coherence tomography was performed in 53 subjects with moderate or high myopia (53 eyes; myopia group) and 20 emmetropic subjects (20 eyes; control group). All subjects were over the age of 40 years. RESULTS: Compared groups did not differ in age, sex, and radius of corneal curvature. Spherical equivalent in the myopia group was - 8.2 ± 3.3 D (from - 4.0 to - 22.6 D). A specialized computer program was created to study the effect of the ocular magnification on the average GCIPL thickness. Based on the data of control subjects, a mathematical model was constructed, which showed a very little effect of ocular magnification on GCIPL thickness. It was confirmed by real measurements. After correction by the program, GCIPL thickness in myopes increased only slightly (from 73.9 ± 5.2 to 75.0 ± 5.2 µm, P < 0.000) remaining much lower than in controls (79.7 ± 6.3 µm, P < 0.000). Modeling myopic eye as an ellipsoid showed a significant increase in its surface area compared with emmetropia. Retinal stretching associated with an increase in the surface area of the eyeball explained most of the thinning of GCIPL in myopia. CONCLUSIONS: Ocular magnification is responsible for only a minor part of GCIPL thinning in myopia. Stretching of the retina in a long eye is the main cause of the GCIPL thinning. Myopic normative databases should be created to account for the GCIPL thinning in highly myopic eyes.

Profile of macular ganglion cell-inner plexiform layer thickness in healthy 6.5 year- old Swedish children.

BACKGROUND: The purpose was to study the macular ganglion cell- inner plexiform layer (GC-IPL) thickness in healthy 6.5 year- old Swedish children using Optical Coherence Tomography (OCT) and to study topography symmetry within eyes and between eye pairs. METHODS: A total of 181 eyes of 92 healthy children (39 girls, 53 boys) aged 6.5 and serving as a term-born control group in the Extremely Preterm Infants in Sweden Study (EXPRESS), were examined with Cirrus HD-OCT. Main outcome measures were average and minimum values of GC-IPL thickness of the device's predefined macular sectors. Single sectors, combined sectors defined as superior and inferior hemispheres and temporal and nasal sectors were evaluated. Intra-individual GC-IPL thickness between eye pairs was analyzed. Visual acuity, refraction and general cognition were assessed and correlated to GC-IPL outcome. RESULTS: Eighty-five children completed the OCT examination and 155 out of 181 scans (86%) were analyzed. The mean average GC-IPL thickness was 85.9 µm (± 5.3; 5th and 95th percentiles were 76.0 and 94.6 µm). The mean minimum GC-IPL thickness was 83.6 µm (± 4.9; 5th and 95th percentiles were 75.4 and 92.3 µm). The difference in thickness between nasal and temporal sectors and between superior and inferior hemisphere sectors were less than 2 µm. The difference between average GC-IPL thickness and minimum GC-IPL thickness was 2.3 µm (± 1.9; 5th and 95th percentiles were 0.0 and 6.0 µm). The difference between the thickest and thinnest sector within eye was 6.4 µm (± 2.2; 5th and 95th percentiles were 3.0 and 10.0 µm). There was a moderate correlation in the difference between the nasal combined and the temporal combined sectors within eye pairs (p < 0.0001, Spearman's ρ 0.58). The average GC-IPL thickness was weakly positively correlated with SE (spherical equivalent; combined sphere and ½ cylinder) (p = 0.031, Spearman's ρ 0.23). CONCLUSIONS: This study provides normative GC-IPL thickness values for healthy 6.5 year- old Swedish children. The GC-IPL thickness variations within eyes and within eye pairs are generally small. It could therefore be assumed that larger variations are sensitive markers of focal GC-IPL thinning due to damage to the primary visual pathways in children.

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.

Characteristics of the Foveal Microvasculature in Asian Patients with Dry Age-Related Macular Degeneration: An Optical Coherence Tomography Angiography Study.

PURPOSE: To evaluate changes in the foveal microvasculature in patients with dry age-related macular degeneration (dry AMD) using optical coherence tomography angiography (OCTA). METHODS: Eighty-three eyes with dry AMD and 83 age- and sex-matched normal eyes were enrolled. A 3 × 3 mm2 OCTA (Zeiss HD-OCT 5000 with AngioPlex; Carl Zeiss Meditec, Dublin, CA, USA) scan was used to acquire images. Vessel density (VD), perfusion density (PD), and the foveal avascular zone (FAZ) of the superficial capillary plexus were analyzed. RESULTS: The VD of the full area, central area, and inner ring of the dry AMD patients (18.61, 8.41, and 20.45, respectively) were significantly lower than those of the controls (20.06, 11.09, and 22.51, respectively). The PD of the full area, central area, and inner ring of the dry AMD patients (0.34, 0.15, and 0.37, respectively) were also significantly lower than those of the controls (0.36, 0.19, and 0.40, respectively). The FAZ area and perimeter in the dry AMD patients (0.29 mm2 and 2.47 mm, respectively) were larger than those in the controls (0.23 mm2 and 2.09 mm, respectively). The FAZ circularity index in the dry AMD patients was smaller than that in the controls (0.61 vs. 0.66). Using univariate linear regression, age, best-corrected visual acuity (BCVA), central macular thickness (CMT), and ganglion cell-inner plexiform layer (GC-IPL) thickness were associated with both VD and PD of the full area. Using multivariate analysis, only GC-IPL thickness was significantly associated with the VD and PD of the full area (p = 0.001 and p = 0.004, respectively). CONCLUSIONS: OCTA revealed changes in the foveal microcirculation of patients with dry AMD. Age, BCVA, CMT, and GC-IPL thickness should be considered when analyzing the OCTA data of patients with dry AMD. GC-IPL thickness is particularly important during clinical evaluation of VD and PD in patients with dry AMD.

Optical coherence tomography findings in patients with alcohol use disorder and their relationship with clinical parameters.

Purpose: In our study, we aimed to investigate the ganglion cell-inner plexiform layer thickness (GCIPL), retinal nerve fibre layer thickness (RNFL), mean macular volume (MMV), central macular thickness (CMT), mean macular thickness (MMT), and choroidal thickness (CT) values with optical coherence tomography (OCT) in patients who are diagnosed with alcohol use disorder (AUD).Materials and methods: The study included 43 patients who were diagnosed with AUD, and 43 healthy controls. Detailed biomicroscopic examinations of all the participants, visual acuity, intraocular pressure, anterior and posterior segment examinations, and then, OCT measurements were carried out.Results: Although the measured values for RNFL in the superior and temporal quadrant are within normal limits, they were slightly higher compared to those in the control group (p values 0.127 and 0.191 for superior quadrant and temporal quadrant, respectively). The CT measurements in all quadrants were higher than the control group; however, these measurements were not statistically significant (p > 0.05). When the relation between clinical features and OCT findings of the patients were examined, it was determined that the ages of the patients were statistically significantly and inversely correlated with the temporal CT and also the nasal and temporal quadrants of RNFL.Conclusions: Our study is the first study that examines the retinal GCIPL and CT with OCT in patients who are diagnosed with AUD. In our results, it was determined that there were no statistically significant differences between the participants in terms of OCT parameters. Further studies with larger sampling groups evaluating neurotransmission findings may provide wider results.

Comparison of retinal layer thickness measurements obtained using two different swept-source optical coherence tomography imaging modes.

PURPOSE: To compare the retinal layer thickness values obtained using two swept-source optical coherence tomography (OCT) wide modes. METHODS: This study included fifty-four healthy eyes. Three-dimensional (3D) wide and 12 radial wide OCT scans were performed in each eye on the same day. Full retinal, retinal nerve fiber layer (RNFL), and ganglion cell-inner plexiform layer (GC-IPL) thicknesses with fully automated segmentation obtained in 3D wide mode, and with semi-automated correction and fully automated segmentation obtained in 12 radial wide scan. RESULTS: The intraclass correlation coefficients for full retinal thickness measurements obtained by the two protocols with fully automated segmentation were from 0.958 to 0.996, 0.754-0.918 for GC-IPL thickness measurements, and 0.013-0.727 for RNFL thickness measurements, in the nine ETDRS subfields. CONCLUSIONS: The full retinal thickness measurements determined using both fully automated segmentation algorithms were reliable and clinically acceptable. However, segmentation errors are shown when using the 12 radial wide scanning protocol with fully automated segmentation for measurement of RNFL and GC-IPL thickness.

Comparison of glaucoma diagnostic ability of ganglion cell-inner plexiform layer according to the range around the fovea.

BACKGROUND: To compare the glaucoma diagnostic ability of the ganglion cell-inner plexiform layer (GCIPL) thickness depending on the range around the fovea using wide-angle, swept-source optical coherence tomography (SS-OCT). METHODS: We compared the glaucoma diagnostic utility of GCIPL parameters across multiple regions while centered on the fovea. In a wide-angle scan, the GCIPL for each 1-mm2 grid square of a 12 × 9 mm2 scan resulted in 108 data points. With respect to the range of the GCIPL measurements around the macula, the wide-angle scan images were classified into three zones. Zone 1 was defined as a narrow area; zone 2 was defined as a mid-sized area; and zone 3 was defined as a wide area. We recorded the quadrant GCIPL thickness, average, and minimum quadrant GCIPL within each zone. The areas under the receiver operating characteristic (AUROCs) curves were calculated to evaluate the glaucoma diagnostic utility. RESULTS: Sixty-one eyes with glaucoma and 59 normal eyes were assessed. The minimum and average GCIPL measurements in zones 1-3 in eyes with glaucoma were significantly lower than those in normal eyes (P <  0.001). The AUROCs for the minimum and inferotemporal GCIPL in zone 1 and the inferotemporal GCIPL thickness in zone 2 were greater than 0.9 (0.945, 0.931, and 0.918, respectively). CONCLUSIONS: Wide-angle scanning using SS-OCT will contribute to improvements in the detection of glaucomatous damage. The minimum and inferotemporal GCIPL in zone 1 may be more useful for detecting glaucoma than those in the conventional area.