Optic Nerve Head Parameters Research Articles

The comparison of optic disc parameters and the thickness of circumpapillary retinal nerve fiber layer between acute Vogt-Koyanagi-Harada syndrome and acute central serous chorioretinopathy

Objective To compare the differences of optic nerve head (ONH) parameters and the thickness of circumpapillary retinal nerve fiber layer (CP-RNFL) between acute Vogt-Koyanagi-Harada syndrome (VKH) and acute central serous chorioretinopathy (CSC) patients. Methods Retrospective clinical case control analysis. This study included 38 eyes of 20 acute VKH patients (VKH group) and 37 eyes of 37 acute CSC patients (CSC group). Seventy five eyes of 57 normal healthy subjects, matching patients with age and gender, were collected as control group. The disc RPE angle, the thickness of average CP-RNFL, the nasal, superior, temporal and inferior quadrant CP-RNFL thickness, and ONH parameters including optic disc area, cup area, rim area, C/D area ratio, linear CD ratio (CDR), vertical CDR were measured by 3D-OCT. Analysis of variance was performed for comparison among three groups. Minimum significant difference t test was performed for comparison between two groups. Results The differences of ONH parameters between VKH group and CSC group: 29 eyes of VKH group appeared retinal detachment next to disc, only 12 eyes appeared in CSC group. Twenty one eyes of VKH group appeared optic disc hyperemia while none in CSC group. The three groups’ disc RPE angles were (138.62±11.96)°, (154.09±5.85)° and (153.41±5.77)°. VKH group were significantly smaller than CSC group (t=-2.05, P=0.00) and control group (t=-1.68, P=0.00), while there was no significant difference between CSC group and control group (t=-1.88, P=0.72). The optic cup area and rim area were significantly bigger in VKH group than in CSC group (t=4.61, 2.71; P=0.00, 0.01), and the thickness of mean CP-RNFL, all quadrants of CP-RNFL were significantly thicker in VKH group than in CSC group (t=6.25, 4.40, 3.53, 5.48, 2.69; P=0.00, 0.00, 0.00, 0.00, 0.01). Conclusion Compared with the acute CSC, VKH patients are likely to appear retinal detachment next to disc, their disc RPE angles are smaller, their optic cup area and rim area are bigger, and their CP-RNFL thickness are thicker. Key words: Uveomeningoencephalitic syndrome; Central serous chorioretinopathy; Optic disk; Nerve fibers; Tomography, optical coherence

Optical coherence tomography of the retina, nerve fiber layer, and optic nerve head in dogs with glaucoma.

To evaluate the retina and optic nerve head (ONH) in canine eyes predisposed to glaucoma using optical coherence tomography (OCT). Twenty-five eyes (24 dogs). Measures of peripapillary retinal, retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) thickness and ONH parameters were obtained in vivo by OCT of the unaffected eye in dogs diagnosed with unilateral primary glaucoma (predisposed; n=12) and compared with measures of healthy control eyes (normal; n=13). Repeatability and intrarater reliability were explored using intraclass correlation coefficients (ICC). Compared to normal eyes, predisposed eyes had a thinner retina in the temporal (P=0.005), inferior quadrants (P=0.003), and decreased inner retinal thickness (superior: P=0.003, temporal: P=0.001, inferior: P<0.001, nasal: P=0.001). Predisposed eyes had a thinner RNFL compared to normal eyes (P=0.005), and when analyzed in quadrants, it was thinner in the superior (P<0.001), temporal (P=0.034), and nasal quadrants (P=0.001). Repeatability (ICC 0.763-0.835) and intrarater reliability (ICC 0.824-0.942) were good to excellent for measures of retinal thickness and adequate for RNFL measurements (ICC 0.701-0.798). Reliable measurements of optic disk area were obtained and were similar between groups (P=0.597). Measurements of parameters relying on automated software detection (GCC, optic cup, optic rim) had inadequate repeatability and reliability. Statistically significant differences in retinal and RNFL thicknesses were identified in normal and predisposed eyes. Reliable and consistent measurements of variables with manual adjustment of software detected parameters were obtained. Validation of OCT as a diagnostic tool for clinical assessment in canine glaucoma is warranted.

Papilloedema: diffusion-weighted imaging of optic nerve head

To establish the correlation between clinical grading of papilloedema and diffusion abnormalities of optic nerve head (ONH) on diffusion-weighted imaging (DWI). Brain magnetic resonance imaging (MRI), including readout segmented echo planar imaging-based DWI, was performed in 32 patients with papilloedema and the same number of age- and sex-matched controls. Clinical grading of papilloedema was done according to the modified Frisén scale. Two neuroradiologists independently evaluated the MRI for ONH hyperintensity and apparent diffusion coefficient (ADC) value of ONH. The comparison between papilloedema clinical grade and qualitative grade of ONH hyperintensity and its presence between cases and control groups were done using the Chi-square test and Fisher's exact test, respectively. The comparison between mean ADC value of ONH among different grades and between cases and controls were done using analysis of variance (ANOVA)-F-test and Student's t-test, respectively. Receiver operating characteristic (ROC) analysis was done to calculate a cut-off ADC value between the case and control groups. Significant correlation between ONH hyperintensity and mean ADC value of ONH with clinical grades of papilloedema and between cases and control groups were found. ONH hyperintensity was found to be a highly sensitive (87.5% for both) and specific (specificity 97.1% and 98.6% for two observers) sign of papilloedema. A mean cut-off ONH ADC value was found to have high sensitivity (96.83%) and specificity (95.31%) to distinguish between the cases and controls. Diffusion parameters of ONH have significant correlation with clinical grading of papilloedema and can serve as a surrogate marker for intracranial pressure.

Optical coherence tomography findings in chronic progressive external ophthalmoplegia.

Background:Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial encephalomyopathy caused by multiple mtDNA abnormalities. There is little information about the changes of ocular fundus with CPEO. The aim of this work was to measure and evaluate changes in the macular retinal thickness and optic nerve head in patients with CPEO using spectral-domain optical coherence tomography and to compare the findings with those of healthy individuals.Methods:Totally, 18 CPEO patients were enrolled in this study. Healthy volunteers matched for gender, age, and diopter settings were included as a control group. The retinal thickness of macular central fovea, inner and outer retinal layer thickness of perifoveal macular, optic nerve head parameters, and peripapillay retinal nerve fiber layer thickness (pRNFLT) for all included cases were measured using spectral-domain optical coherence tomography. A paired t test was used to compare the differences in the studied parameters between the two groups. The correlations between macular retinal thickness, pRNFLT, disease duration, and age of onset were also analyzed.Results:Among the macular parameters, retinal thickness of macular central fovea (t = −2.135, P < 0.05) and outer retinal layer thickness (t = −1.994, P < 0.05) of patients in the CPEO group were statistically significant lower than those of patients in the normal control group. For the optic nerve head parameters, the patients in the CPEO group showed a larger rim volume (t = −2.499, P < 0.05) and nerve head volume (t = −2.103, P < 0.05). The overall pRNFLT of patients in the CPEO group was statistically significant lower than that of patients in the control group (t = −4.125, P < 0.05). The comparison of pRNFLT in eight sectors showed that the pRNFLT of patients in the CPEO group was statistically significant lower than that of the control group mainly in the inferior and temporal sectors. The degree of pRNFL defect negatively correlated with the disease duration (r = −0.583, P < 0.05).Conclusions:The retinal thickness of patients with CPEO was significantly thinner, which was mostly the outer retina. The patients’ optic discs had a low volume and the loss of the retinal nerve fiber layer was obvious. With the extension of the disease duration, the retinal nerve fiber layer defect was even more significant.

Evaluation of Optic Nerve Head Parameters, Retinal Nerve Fiber Layer Thickness, and Ocular Perfusion Pressure in Migraine Patients.

BackgroundNeurovascular changes occur during the migraine is believed to cause alteration in cerebral and retinal circulation that possible result in damage to the brain and even retina or optic nerve. Retinal nerve fiber layer (RNFL) thickness measurement can be used as an index to assess ganglion cell and retinal nerve fiber damages. The aim of this study was to evaluate the optic nerve head (ONH) parameters, RNFL thickness, and ocular perfusion pressure (OPP) in migraine patients.MethodsThis was a cross-sectional study, conducted in Hospital Universiti Sains Malaysia, Kelantan from July 2016 to November 2018, involving patients with a confirmed diagnosis of migraine and controls. Ninety-four eyes of 47 migraine patients and 94 eyes of 47 healthy subjects were included in this study. Blood pressure and intraocular pressure were measured and OPP was calculated. ONH parameters and RNFL thickness were measured using optical coherence tomography (OCT) after pupillary dilatation. Statistical analysis was done using Statistical Package for the Social Science (SPSS Inc Version 24).ResultsWith respect to all means values of ONH parameters, there was no statistically significant difference between migraine patients and controls. For RNFL, there were significant reductions in average and superior RNFL thickness on both eyes with adjustment of age and gender (P-value: right eye (RE) average = 0.027; RE superior = 0.034; left eye (LE) average = 0.037; LE superior = 0.031). In view of OPP, there was no significant difference between migraine patients and controls (P-value = 0.172). Weak correlations were found between the ONH parameters and RNFL thickness with OPP, respectively, in migraine patients.ConclusionThis study showed no difference in ONH parameters between migraine patients and healthy subjects. There was significant thinning in average and superior RNFL for migraine patients. No difference found in OPP between both groups. ONH parameters and RNFL thickness had a weak correlation with OPP in migraine patients.

Effects of chronic elevated intraocular pressure on parameters of optical coherence tomography in rhesus monkeys.

To determine the progression of parameters from optical coherence tomography (OCT) in chronic elevated intraocular pressure (IOP) monkeys. A chronic elevated IOP model of rhesus monkeys was induced by laser photocoagulation. Representative OCT parameters, including the average and four-quadrant retinal nerve fiber layer (RNFL) thickness, and parameters from optic nerve head (ONH) analysis were collected before and after laser treatments biweekly for up to 28wk. The performance of each parameter for early progression detection was analyzed. The progressive trends toward elevated IOP were analyzed using a linear mixed-effects model. There were 10 successfully maintained high IOP eyes in 7 monkeys. The follow-up time was 24±5.37wk. With cumulative IOP elevation, the cup area, rim area and C/D area ratio were statistically significantly changed as early as 2wk after elevated IOP induction (P<0.05). The quadrant RNFL thickness changed at 6wk after high IOP induction, and the superior and inferior RNFL thicknesses exhibited more obvious reductions than other quadrants. The average RNFL thickness was the last one to show a significant decrease at 8wk. The parameters of ONH are most sensitive to elevated IOP in a primate glaucomatous model. These findings suggest that we should focus on those parameters instead of RNFL thickness in patients with elevated IOP, as they might present with earlier glaucomatous changes.

Topographic changes measured by the swept source optical coherence tomography in retinal nerve fiber layer, optic nerve head and macula in children with migraine.

As a vascular-inflammatory disease, migraine affects the brain and some other organs, such as the eye. The aim of this study was to measure and compare the peripapillary retinal nerve fiber layer (RNFL) thickness, macular ganglion cell layer thickness and optic nerve head parameters to detect structural damage in children with migraine using swept-source optical coherence tomography. Twenty-four children with migraine in the painless period and 26 controls were included in the study. The vast majority of the groups consisted of females (75% for patients and 77% for controls). Certain RNFL quadrants and optic disc parameters revealed significant differences between the patients and controls. In the right and left eyes of children with migraine, nasal quadrant RNFL was significantly thicker than that in healthy subjects (88.82 ± 11.03 vs 77.80 ± 13.77, P = 0.004 for right eyes and 87.71 ± 11.79 vs 77.80 ± 13.77, P = 0.01 for left eyes). Temporal quadrant RNFL in the left eyes was thinner (78.67 ± 9.57 vs 84.44 ± 9.68, P = 0.04). Disc area in the left eyes of the patients was greater (2.29 ± 0.46 vs 1.94 ± 0.28, P = 0.003). There were significant expansions in cup volumes in favor of the patients for right and left eyes (0.15 ± .0.19 vs 0.05 ± 0.05, P = 0.03 and 0.17 ± 0.14 vs 0.05 ± 0.05, P = 0.001, respectively). The only significant difference between the left and right eyes of the migraineurs was the RNFL thickness in the superior quadrant. Ganglion cell layer thickness did not differ between the right eyes, left eyes and controls. In conclusion, children with migraine showed significant variations in specific RNFL and optic disc parameters compared to control subjects.

Discriminating performance of macular ganglion cell-inner plexiform layer thicknesses at different stages of glaucoma.

To determine the discriminating performance of the macular ganglion cell-inner plexiform layer (GC-IPL) parameters between all the consecutive stages of glaucoma (from healthy to moderate-to-severe glaucoma), and to compare it with the discriminating performances of the peripapillary retinal nerve fiber layer (RNFL) parameters and optic nerve head (ONH) parameters. Totally 147 eyes (40 healthy, 40 glaucoma suspects, 40 early glaucoma, and 27 moderate-to-severe glaucoma) of 133 subjects were included. Optical coherence tomography (OCT) was obtained using Cirrus HD-OCT 5000. The diagnostic performances of GC-IPL, RNFL, and ONH parameters were evaluated by determining the area under the curve (AUC) of the receiver operating characteristics. All GC-IPL parameters discriminated glaucoma suspect patients from subjects with healthy eyes and moderate-to-severe glaucoma from early glaucoma patients (P<0.017, for all). Also, minimum, inferotemporal and inferonasal GC-IPL parameters discriminated early glaucoma patients from glaucoma suspects, whereas no RNFL or ONH parameter could discriminate between the two. The best parameters to discriminate glaucoma suspects from subjects with healthy eyes were superonasal GC-IPL, superior RNFL and average c/d ratio (AUC=0.746, 0.810 and 0.746, respectively). Discriminating performances of all the parameters for early glaucoma vs glaucoma suspect comparison were lower than that of the other consecutive group comparisons, with the best GC-IPL parameters being minimum and inferotemporal (AUC=0.669 and 0.662, respectively). Moreover, minimum GC-IPL, average RNFL, and rim area (AUC=0.900, 0.858, 0.768, respectively) were the best parameters for discriminating moderate-to-severe glaucoma patients from early glaucoma patients. GC-IPL parameters can discriminate glaucoma suspect patients from subjects with healthy eyes, and also all the consecutive stages of glaucoma from each other (from glaucoma suspect to moderate-to-severe glaucoma). Further, the discriminating performance of GC-IPL thicknesses is comparable to that.

Structure-function relationships in glaucoma using enhanced depth imaging optical coherence tomography-derived parameters: a cross-sectional observational study

BackgroundTo investigate structural and functional correlations in glaucoma patients using enhanced depth imaging spectral-domain optical coherence tomography (EDI OCT)-derived parameters.MethodsWe prospectively enrolled healthy participants and glaucomatous patients with a wide range of disease stages. All participants underwent visual field (VF) testing (SITA - Standard 24–2; Carl Zeiss Meditec, Dublin, CA) and EDI OCT imaging (Spectralis; Heidelberg Engineering Co., Heidelberg, Germany). The following optic nerve head parameters were measured on serial vertical EDI OCT B-scans by two experienced examiners masked to patients clinical data: lamina cribrosa (LC) thickness and area, prelaminar neural tissue thickness and area, anterior LC depth, Bruch’s membrane opening (BMO) and average, superior, and inferior BMO-minimum rim width (BMO-MRW). Only good quality images were considered, and whenever both eyes were eligible, one was randomly selected for analysis. Scatter plots were constructed to investigate correlations between each anatomic parameter and patient’s VF status (based on VF index [VFI] values).ResultsA total of 73 eyes of 73 patients were included. All EDI OCT parameters evaluated differed significantly between glaucomatous and control eyes (P ≤ 0.045). A secondary analysis, in which glaucomatous patients were divided according to VF mean deviation index values into 3 groups (mild [G1; > − 6 dB], moderate [G2; − 6 to − 12 dB] and advanced [G3; <− 12 dB] glaucoma), revealed that average BMO-MRW was the EDI OCT parameter that presented more significant differences between the different stages of glaucoma. Significant structure-function correlations were found between VFI values and prelaminar neural tissue area (R2 = 0.20, P = 0.017), average BMO-MRW (R2 = 0.35, P ≤ 0.001), superior BMO-MRW (R2 = 0.21, P = 0.012), and inferior BMO-MRW (R2 = 0.27, P = 0.002). No significant correlations were found for LC area and anterior LC depth (P ≥ 0.452).ConclusionsEvaluating the distribution pattern and structure-function correlations of different laminar and prelaminar EDI OCT-derived parameters in glaucomatous patients, we found better results for neural tissue-based indexes (compared to LC-derived parameters). The diagnostic utility of each parameter deserves further investigations.

Automatic Assessment of Biometric Parameters in Optic Nerve Head Area by “Zhongshan ONH Calculator (ZOC)”

ABSTRACTPurpose: To test the repeatability and reproducibility of the Zhongshan ONH Calculator (ZOC) software in terms of selected optic nerve head (ONH) parameters commonly used in clinical research of glaucoma.Materials and methods: Forty-two horizontal single-line scans were selected to test the repeatability and reproducibility of the ZOC software. Clinically relevant 2D parameters of the ONH area were selected to test repeatability of ZOC, including length of BMO, minimum rim thickness on both sides (RIML and RIMR), optic cup depth (OCD), and depth of the anterior surface of the LC (ALCD).Results: Intraobserver test showed higher the intra-class correlation coefficient (ICC) of BMO ((0.991 vs. 0.777), RIML (0.988 vs. 0.890), RIMR (0.972 vs. 0.846), OCD (0.997 vs. 0.992), and ALCD (0.993 vs. 0.949) by single researcher using ZOC software than manual measurement. BA analysis showed acceptable agreement between automatic and manual measurements. SDs and limits of agreement (95% CI) of BMO, RIML, RIMR, OCD, and ALCD were 0.05 (−0.13, 0.07), 0.03 (−0.05, 0.05), 0.03 (−0.06, 0.07), 0.015 (−0.035, 0.024), and 0.04 (−0.07, 0.08), respectively.Conclusion: This study presented the design and development of software for the automatic measurement of OCT images of ONH area with good reproducibility. In the future, with advances of OCTs and improvements to the resolution of the LC, ZOC will become a powerful tool in glaucoma research.

Increased prelaminar tissue thickness in patients with open-angle glaucoma and type 2 diabetes.

BackgroundThe characteristics of the optic nerve head (ONH) in open angle glaucoma (OAG) patients with diabetes have not been reported. This study aimed to characterize the ONH structures and glaucomatous damage in diabetic OAG patients, using age-matched non-diabetic OAG patients and control subjects.MethodsThe locations of visual field defects of OAG patients were classified and the prelaminar thickness and lamina cribrosa depth were measured in 64 OAG patients with type 2 diabetes (OAG+DM), 68 OAG patients without diabetes (OAG-DM), and 36 controls. All participants were scanned by spectral domain-optical coherence tomography. The anterior prelaminar depth and lamina cribrosa depth were measured at the center of the reference line (the Bruch’s membrane opening plane). The prelaminar tissue thickness was obtained by subtracting the anterior prelaminar depth from the anterior lamina cribrosa depth.ResultsThe visual field defects in the OAG+DM group were more commonly found in the inferior hemifield (P = 0.010), and tended to involve the central visual field compared to the OAG-DM group (P = 0.044). In the comparison of ONH parameters, the prelaminar thickness was highest in the OAG+DM group, followed by the control subjects and the OAG-DM group (P = 0.035). Post-hoc testing showed that prelaminar thickness was significantly greater in the OAG+DM group than in the OAG-DM group (P = 0.033). The lamina cribrosa depth was deepest in the OAG+DM group, followed by the OAG-DM group and the control subjects (P = 0.006).ConclusionsDiabetic and non-diabetic OAG patients exhibit different characteristics of glaucoma, particularly increased prelaminar thickening in diabetics.

Diagnostic ability of macular ganglion cell asymmetry in Preperimetric Glaucoma

BackgroundTo evaluate the diagnostic ability of macular ganglion cell asymmetry to diagnose preperimetric glaucoma (PPG), using Cirrus spectral domain optical coherence tomography (OCT).MethodsThis prospective study included 67 eyes of 67 patients with PPG and 67 eyes of 67 age- and refractive error-matched controls. We measured circumpapillary RNFL (cpRNFL) thickness, macular ganglion cell-inner plexiform layer (GCIPL) thickness and optic nerve head (ONH) parameters using OCT. Macular ganglion cell asymmetries were expressed as absolute difference and ratios between inferior hemisphere and superior hemisphere, inferotemporal (IT) and superotemporal (ST), IT and superonasal (SN), IT and inferonasal (IN), ST and IN as well as temporal and nasal. An asymmetry index was assigned by taking the absolute value of log10 of the ratio. The area under the receiver operating characteristics curve (AUROC), partial AUROC (pAUROC) ≥ specificities 90 and 95%, cutoff values and sensitivities at specificities 90 and 95% was analyzed.ResultsParameters with largest AUROCs were IT GCIPL thickness (0.784), average RNFL thickness (0.767), and average C/D (0.746). For macular asymmetry parameters, log IT/SN index had the largest AUROC (0.734), followed by log IT/IN index (0.725), and absolute difference of IT−SN GCIPL thickness (0.715). Performance was comparable between the best measures of asymmetry analysis (log IT/SN index) and those of cpRNFL, GCIPL, and ONH parameters (all P > 0.05). The IT/SN asymmetry index not only had the largest pAUROC based on the pAUROCs ≥90 and 95% specificity (0.044 and 0.019) but also had the highest diagnostic sensitivity at 90 and 95% specificities (52.2 and 46.3%).ConclusionsGCIPL asymmetry measurements have diagnostic ability comparable to cpRNFL, GCIPL, and ONH analysis for PPG. The best macular ganglion cell asymmetry parameter was IT/SN asymmetry index, which could be a new parameter to detect early structural changes in PPG.

Choroidal Thickness and its Correlations with Ocular Parameters in Primary Open-angle Glaucoma.

Objectives:To evaluate the relationships between macular choroidal thickness (mCT) and ocular parameters, such as optic nerve head (ONH) and multifocal electroretinogram (mf-ERG) parameters, in cases with primary open-angle glaucoma (POAG).Methods:This controlled and prospective clinical trial included 49 patients with POAG diagnosed for the fırst time and 47 healthy participants. Macular CTs, ONH and mf-ERG parameters were measured, and the examination findings were recorded at baseline and follow-ups.Results:In the POAG group, the mean mCT was 254.92±37.65 µm at baseline, and it was 235.6±38.48 µm at 3-month and was 237.55±37.27 µm at 6-month. In the glaucoma group, there was a significant decrease in the first three months despite the treatment, but no significant change was observed in the next three months. In the healthy group, the mean mCTs were 287.78±26.77 µm, 285.48±25.58 µm and 285.02±27.44 µm at baseline, at 3-month and at 6-month, respectively. No significant change was observed in the control group throughout the process. However, the mean mCT values in the glaucoma group were significantly thinner in all controls compared to the healthy group (p<0.05). Furthermore, significant correlations were found between CT and some ONH, as well as mf-ERG parameters.Conclusion:The choroid can play an important role in the pathogenesis of glaucoma. Significant correlations in parameters support this relationship. We have observed that the glaucomatous effect initiated first in the inferior quadrant of ONH.

Clinical validation of RIA-G, an automated optic nerve head analysis software.

Purpose:To clinically validate a new automated glaucoma diagnosis software RIA-G.Methods:A double-blinded study was conducted where 229 valid random fundus images were evaluated independently by RIA-G and three expert ophthalmologists. Optic nerve head parameters [vertical and horizontal cup–disc ratio (CDR) and neuroretinal rim (NRR) changes] were quantified. Disc damage likelihood scale (DDLS) staging and presence of glaucoma were noted. The software output was compared with consensus values of ophthalmologists.Results:Mean difference between the vertical CDR output by RIA-G and the ophthalmologists was − 0.004 ± 0.1. Good agreement and strong correlation existed between the two [interclass correlation coefficient (ICC) 0.79; r = 0.77, P < 0.005]. Mean difference for horizontal CDR was − 0.07 ± 0.13 with a moderate to strong agreement and correlation (ICC 0.48; r = 0.61, P < 0.05). Experts and RIA-G found a violation of the inferior–superior NRR in 47 and 54 images, respectively (Cohen's kappa = 0.56 ± 0.07). RIA-G accurately detected DDLS in 66.2% cases, while in 93.8% cases, output was within ± 1 stage (ICC 0.51). Sensitivity and specificity of RIA-G to diagnose glaucomatous neuropathy were 82.3% and 91.8%, respectively. Overall agreement between RIA-G and experts for glaucoma diagnosis was good (Cohen's kappa = 0.62 ± 0.07). Overall accuracy of RIA-G to detect glaucomatous neuropathy was 90.3%. A detection error rate of 5% was noted.Conclusion:RIA-G showed good agreement with the experts and proved to be a reliable software for detecting glaucomatous optic neuropathy. The ability to quantify optic nerve head parameters from simple fundus photographs will prove particularly useful in glaucoma screening, where no direct patient–doctor contact is established.

The effect of panretinal photocoagulation on confocal laser scanning ophthalmoscopy and stereo photographic parameters of optic disk topography in patients with diabetic retinopathy.

To determine the effect of panretinal photocoagulation on optic disk topographic parameters in non-glaucomatous patients with proliferative diabetic retinopathy. This was a prospective, single-center, observational study. Thirty-eight eyes of 26 patients with diabetes underwent panretinal photocoagulation for proliferative diabetic retinopathy. Stereoscopic disk photographs and optic nerve head parameters were evaluated using the Zeiss fundus camera and the confocal scanning laser ophthalmoscope (Heidelberg Retinal Tomograph), respectively, at baseline and 12 months after the completion of panretinal photocoagulation. Thirty-eight eyes of 26 patients (15 female) with a mean age of 53.7 (range 26-74) years were recruited. No significant difference was found between the stereo photography determined mean horizontal and vertical cup-to-disk ratio before and after panretinal photocoagulation treatment (p=0.461 and 0.839, respectively). The global values of the optic nerve head parameters analyzed with the HRT3 showed no significant change from baseline to 12 months, including the disk area, cup area, rim area, cup volume, rim volume, cup-to-disk area ratio, linear cup-to-disk ratio, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean retinal nerve fiber layer thickness, and cross-sectional area. Our results suggest that panretinal photocoagulation does not cause morphological optic disk changes in patients with diabetic proliferative retinopathy after 1 year of follow-up.

Linear discriminant score for differentiating early primary open angle glaucoma from glaucoma suspects.

Purpose:To determine the diagnostic accuracy of a linear discriminant function (LDF) based on macular ganglion cell complex (GCC), optic nerve head (ONH) and retinal nerve fibre layer (RNFL) for differentiating early primary open-angle glaucoma (POAG) from glaucoma suspects.Methods:In this cross-sectional study, data from consecutive 127 glaucoma suspects and 74 early POAG eyes were analysed. Each patient underwent detailed ocular examination, standard automated perimetry, GCC and ONH and RNFL analysis. After adjusting for age, gender and signal strength using the analysis of covariance; Benjamin–Hochberg multiple testing correction was performed to detect truly significant parameters to calculate the LDF. Subsequently, diagnostic accuracy of GCC and ONH and RNFL were determined. The obtained LDF score was evaluated for diagnostic accuracy in another test set of 32 suspect and 19 glaucomatous eyes. Data were analysed with the R-3.2.1 (R Core Team 2015), analysis of variance, t-test, Chi-square test and receiver operating curve.Results:Among all GCC parameters, infero temporal had the best discriminating power and average RNFL thickness and vertical CDR among ONH and RNFL parameters. LDF scores for GCC had AUROC of 0.809 for a cut-off value 0.07, while scores for ONH and RNFL had AUROC of 0.903 for a cut-off value − 0.24. Analysis on combined parametric space resulted in avg RNFL thickness, vertical CDR, min GCC + IPL and superior GCC + IPL as key parameters. LDF scores obtained had AUROC of 0.924 for a cut-off value 0.1. The LDF was applied to a test set with an accuracy of 84.31%.Conclusion:The LDF had a better accuracy than individual GCC and ONH and RNFL parameters and can be used for diagnosis of glaucoma.

Has Spectral-Domain Optical Coherence Tomography Retinal Nerve Fiber Layer Assessment Become the Method of Choice for Glaucoma Evaluation in Clinical Practice?

AIM:The aim of the study was to assess the role of spectral-domain optical coherence tomography (SD-OCT) as a method of choice for early glaucoma diagnosis in glaucoma suspects.DESIGN:This was a retrospective cross-sectional study.MATERIALS AND METHODS:After a comprehensive ophthalmic examination and visual field analysis, 20 patients were included in each of the three groups: Normal group, possible glaucoma, definitive glaucoma, respectively. The optic nerve head (ONH) and peripapillary retinal nerve fiber layer parameters of participants were analyzed using SD-OCT optic disc cube protocol scans. Data was analyzed using one.way analysis of variance test.RESULTS:ONH RNFL defects in possible glaucoma patients were frequently found in superior, inferior, and temporal quadrants.CONCLUSION:Diagnostic capability of SD-OCT parameters for detection of structural changes in the ONH and retinal nerve fiber layer differed in three groups significantly. Hence, using SD-OCT has become an imperative and quick way of timely diagnosis of glaucoma in private practice.

Comparison of the clinical estimation of cup-to-disk ratio by direct ophthalmoscopy and optical coherence tomography.

Objective:To compare the clinical estimation of cup-to-disk ratio determined by direct ophthalmoscopy and optical coherence tomography in glaucoma diagnosis and monitoring.Methods:A retrospective, cross-sectional study involving a review of 71 optical coherence tomography scans dating from June 2011 to January 2012 at a private imaging lab in Ghana. At the respective referring facilities, only 31 out of the 71 corresponding patient records were successfully reviewed.Results:Majority (54.84%) of the 31 patient records successfully reviewed were women. The mean age was 44.54 ± 16.15 years. Cup-to-disk ratio was grouped into ⩽0.4, >0.4–0.6, >0.6–0.8, and >0.8–1.0 based on direct ophthalmoscopy values. The overall mean cup-to-disk ratio estimated by the optical coherence tomography and direct ophthalmoscopy were 0.72 ± 0.21 and 0.60 ± 0.26, respectively. Overall, there was no statistically significant difference in the mean cup-to-disk ratio estimation by direct ophthalmoscopy and optical coherence tomography [right eye (p = 0.0629); left eye (p = 0.0766)]. There was a statistically significant difference between direct ophthalmoscopy and optical coherence tomography cup-to-disk ratio estimation for values ⩽0.4 [right eye (p = 0.0061); left eye (p = 0.0063)] and values >0.4–0.6 [right eye (p = 0.0243); left eye (p = 0.0498)]. There was no statistically significant difference between conventional direct ophthalmoscopy and optical coherence tomography cup-to-disk ratio estimation for cup-to-disk ratio >0.6.Conclusion:We recommend clinicians document which method they use in evaluating optic nerve head parameters. This is to ensure that subsequent clinical decisions are not influenced by an apparent change in these parameters, especially cup-to-disk ratio as different methods might give different values.

Relationship between retinal vessel diameter with both retinal nerve fibre layer thickness and optic nerve head parameters in middle-aged Caucasians: the Northern Finland Birth Cohort Eye study.

PurposeTo study the normal relationship between retinal vessel diameter (RVD) with retinal nerve fibre layer (RNFL) thickness and optic nerve head (ONH) parameters in a cohort of middle‐aged Caucasians.MethodsWe investigated 3070 individuals (6140 eyes). Central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were measured in the right eye using a semi‐automated computer‐assisted program. Retinal nerve fibre layer (RNFL) thickness and ONH parameters were assessed with Heidelberg retinal tomography (HRT).ResultsData from 2217 persons were analysed including RNFL, CRAE, CRVE, sex, body mass index, mean arterial pressure, diabetes status, smoking status, optic disc area, rim area, spherical refraction and intraocular pressure. A larger RVD was associated with a thicker mean global RNFL thickness especially in global and inferior segments of the retina and with larger optic discs. Each 10 μm increase in the retinal arteriolar calibre was associated with a 5.58 μm increase in mean global RNFL thickness; the corresponding value for a 10 μm increase in venular calibre was 3.79 μm (p < 0.001 for both). Retinal venular calibre displayed consistent associations with RNFL thickness in both genders (p < 0.001 for all), whereas the association of arteriolar calibre and RNFL was more prominent in men (p < 0.001).ConclusionWe found strong associations between larger RVD and thicker RNFL in all subjects. This study helps to clarify the association between RVD, RNFL thickness and ONH parameters and provides normal values for middle‐aged Caucasians that will help in future studies investigating the role of vascular aetiology in systemic and eye diseases.

Quantitative analysis of the retinal nerve fiber layer, ganglion cell layer and optic disc parameters by the swept source optical coherence tomography in patients with migraine and patients with tension-type headache.

The aim of the study was to measure the thicknesses of the inner retinal segments and optic nerve head (ONH) parameters in migraineurs and patients with tension-type headache (TTH) in headache-free period using swept source optical coherence tomography (SS-OCT) and to compare the outcomes with each other and those of healthy subjects. The study population consisted of 23 migraineurs, 22 TTH patients, and 25 controls with a best-corrected visual acuity of 20/20 and without a history of systemic or ocular disease. Macular ganglion cell inner plexiform layer (mGCIPL), macular ganglion cell complex (mGCC), circumpapillary retinal nerve fiber layer (cpRNFL), and ONH parameters were evaluated using SS-OCT, and the areas under the receiver-operating characteristic (ROC) curves were calculated to determine the ability of these parameters to distinguish between the patient and normal eyes. There were not statistically significant differences between the measurements acquired from migraineurs, TTH patients, and the controls. The outcomes of the patients with TTH were very similar to those of the normal participants. The areas under the ROC curves (AUC) correlated highly with the measurements obtained from the same subfields for the mGCC, MGCIPL, cpRNFL, and ONH parameters. In conclusion, SS-OCT presented reproducible and reliable measurements of posterior segment layers of the eyes, especially in sectoral configuration, and the parameters did not show significant difference between the groups.