Influence of refractive error on optic disc topographic parameters: the singapore malay eye study

Longitudinal changes of funduscopic optic disc size, color and cup-to-disc ratio in school children

BACKGROUND

To investigate the relationship between changes in the optic disc size and color, cup-to-disc (C/D) ratio, and axial elongation in schoolchildren.

METHODS

A prospective cohort study was performed in 75 right eyes of elementary school students for six years (from 8.5 to 14.5 years old). In the first and last year, all participants underwent optical axial length measurement and color fundus photography. The optic disc color was calculated by dividing the intensity of red by the sum of the intensity of red, green, and blue. The optic disc area was calculated by modifying the number of pixels according to Bennett's formula. The C/D ratio was calculated by dividing the vertical cup diameter by vertical optic disc diameter. Wilcoxon signed rank test was used to compare these optic disc parameters and axial length in the first and last year.

RESULTS

Mean axial length in the last year (24.82 mm) was significantly longer than that in the first year (23.34 mm). Likewise, the mean optic disc size was significantly smaller in the last year (41,946 pixels) than that in the first year (46,144 pixels). The mean optic disc color in the last year (0.49) was significantly more reddish than that in the first year (0.46), while the mean C/D ratio in last year (0.50) was significantly smaller than that in first year (0.52).

CONCLUSIONS

During the period from 8.5 years to 14.5 years of age, both the optic disc size and C/D ratio became smaller, while the color became more red.

Quantitative assessment of colour fundus photography in hyperopia children based on artificial intelligence

OBJECTIVES

This study aimed to quantitatively evaluate optic nerve head and retinal vascular parameters in children with hyperopia in relation to age and spherical equivalent refraction (SER) using artificial intelligence (AI)-based analysis of colour fundus photographs (CFP).

METHODS AND ANALYSIS

This cross-sectional study included 324 children with hyperopia aged 3-12 years. Participants were divided into low hyperopia (SER+0.5 D to+2.0 D) and moderate-to-high hyperopia (SER≥+2.0 D) groups. Fundus parameters, such as optic disc area and mean vessel diameter, were automatically and quantitatively detected using AI. Significant variables (p<0.05) in the univariate analysis were included in a stepwise multiple linear regression.

RESULTS

Overall, 324 children were included, 172 with low and 152 with moderate-to-high hyperopia. The median optic disc area and vessel diameter were 1.42 mm2 and 65.09 µm, respectively. Children with high hyperopia had larger superior neuroretinal rim (NRR) width and larger vessel diameter than those with low and moderate hyperopia. In the univariate analysis, axial length was significantly associated with smaller superior NRR width (β=-3.030, p<0.001), smaller temporal NRR width (β=-1.469, p=0.020) and smaller vessel diameter (β=-0.076, p<0.001). A mild inverse correlation was observed between the optic disc area and vertical disc diameter with age.

CONCLUSION

AI-based CFP analysis showed that children with high hyperopia had larger mean vessel diameter but smaller vertical cup-to-disc ratio than those with low hyperopia. This suggests that AI can provide quantitative data on fundus parameters in children with hyperopia.

Optic Nerve Head and Retinal Nerve Fiber Layer Analysis in Emmetropic Malay Children

BACKGROUND AND OBJECTIVES

The study aims to investigate the normal reference values for optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters in emmetropic Malay children, utilizing measurements obtained through Cirrus SD-OCT (Carl Zeiss Meditec, Dublin, CA).

METHODOLOGY

A cross-sectional study was conducted on 95 Malay children, aged between seven and 17 years, with no ocular abnormalities. It was held at Hospital Universiti Sains Malaysia, Malaysia, from January 2014 to December 2015. All children underwent a full ocular examination, including refraction and calculation of axial length. ONH and retinal nerve fiber layer thickness (RNFLT) parameters were measured using the Cirrus SD-OCT machine. One eye of each subject was selected randomly for study. The associations between the parameters and the effect of age, gender, axial length, and spherical equivalent (SE) on the measurements were statistically validated.

RESULTS

Ninety-five children were involved in the study, with 65 females (68.4%) and 30 males (31.6%). The mean age was 10.6 (2.82) years, the mean intraocular pressure (IOP) was 14.8 (2.81) mmHg, the mean SE-refraction was 0.12 (0.28) diopters, and the mean axial length was 23.03 (0.76) mm. The mean disc area, rim area, and cup volume were 2.32 (0.40) mm2, 1.53 (0.33) mm2, and 0.204 (0.16) mm3, respectively. The average cup-to-disc ratio (SD) (CDR) and the vertical CDR were 0.55 (0.13) and 0.50 (0.14). Mean (SD) RNFLT was 102.08 (11.08) μm for all patients. There was a strong positive correlation between the average, superior, and inferior RNFLT with the optical disc area. The rim area and the average, superior, inferior, and nasal RNFLT also showed a significant correlation. The inferior RNFLT was negatively correlated with the average CDR. There was also a major influence of gender on the disc area. There were no major age, axial length, and SE influences on the measurements.

CONCLUSIONS

This study provided normative information for ONH and RNFLT parameters in emmetropic Malay children. It was observed that emmetropic Malay males exhibited a significantly larger optical disc area. The increase in RNFLT is correlated with a significant increase in disc and rim areas.

Increase in Bruch's membrane opening minimum rim width with age in healthy children: the Hong Kong Children Eye Study

BACKGROUND/AIMS

To identify normative values and determinants for Bruch's membrane opening (BMO) and the minimum rim width of BMO (BMO-MRW) among healthy children.

METHODS

A population-based cross-sectional study from the Hong Kong Children Eye Study, recruiting 1, 226 children aged 6-8 years. Spherical refractive error, axial length (AL), body mass index and intraocular pressure (IOP) were measured. The optic nerve head and the peripapillary retinal nerve fibre layer (p-RNFL) were imaged through spectral domain-optical coherence tomography, using 24 equally spaced radial B-scans. Global and sectoral BMO-MRW values, BMO area and fovea-to-BMO (FoBMO) angle were calculated. Multiple regression analysis was performed to define the determinants of BMO area and BMO-MRW in relation to demographic and ocular parameters.

RESULTS

The mean values for global BMO-MRW, BMO area and FoBMO angle among children were 345.76±54.08 µm, 2.34±0.49 mm2 and -5.45±4.36°, respectively. Global and sectoral values for BMO-MRW correlated with p-RNFL thickness (r=0.11-0.35, p<0.001). After adjusting for demographic and ocular parameters, global BMO-MRW increased with age (β=6.4, p<0.001) and greater global p-RNFL thickness (β=1.41, p<0.001), but decreased with larger BMO area (β=-47.46, p<0.001) and higher IOP (β=-1.73, p<0.001). Global BMO-MRW did not associate with AL, whereas both BMO area and FoBMO angle associated with AL (β=0.04, p=0.02 and β=0.31, p=0.03, respectively), but not with age.

CONCLUSION

We observed that BMO-MRW increases with age among children. Our results provide normative values and the determinants of BMO parameters among Chinese children.

Pathological myopia classification with simultaneous lesion segmentation using deep learning

BACKGROUND AND OBJECTIVES

Pathological myopia (PM) is the seventh leading cause of blindness, with a reported global prevalence up to 3%. Early and automated PM detection from fundus images could aid to prevent blindness in a world population that is characterized by a rising myopia prevalence. We aim to assess the use of convolutional neural networks (CNNs) for the detection of PM and semantic segmentation of myopia-induced lesions from fundus images on a recently introduced reference data set.

METHODS

This investigation reports on the results of CNNs developed for the recently introduced Pathological Myopia (PALM) dataset, which consists of 1200 images. Our CNN bundles lesion segmentation and PM classification, as the two tasks are heavily intertwined. Domain knowledge is also inserted through the introduction of a new Optic Nerve Head (ONH)-based prediction enhancement for the segmentation of atrophy and fovea localization. Finally, we are the first to approach fovea localization using segmentation instead of detection or regression models. Evaluation metrics include area under the receiver operating characteristic curve (AUC) for PM detection, Euclidean distance for fovea localization, and Dice and F1 metrics for the semantic segmentation tasks (optic disc, retinal atrophy and retinal detachment).

RESULTS

Models trained with 400 available training images achieved an AUC of 0.9867 for PM detection, and a Euclidean distance of 58.27 pixels on the fovea localization task, evaluated on a test set of 400 images. Dice and F1 metrics for semantic segmentation of lesions scored 0.9303 and 0.9869 on optic disc, 0.8001 and 0.9135 on retinal atrophy, and 0.8073 and 0.7059 on retinal detachment, respectively.

CONCLUSIONS

We report a successful approach for a simultaneous classification of pathological myopia and segmentation of associated lesions. Our work was acknowledged with an award in the context of the "Pathological Myopia detection from retinal images" challenge held during the IEEE International Symposium on Biomedical Imaging (April 2019). Considering that (pathological) myopia cases are often identified as false positives and negatives in glaucoma deep learning models, we envisage that the current work could aid in future research to discriminate between glaucomatous and highly-myopic eyes, complemented by the localization and segmentation of landmarks such as fovea, optic disc and atrophy.

Relationship between ocular risk factors for glaucoma and optic disc rim in normal eyes

AIM

To study relationships between reported risk factors for glaucoma and neuroretinal rim area in normal eyes.

METHODS

The Kumejima study participants, 3762 of the 4632 eligible Kumejima residents 40 years and older, underwent a detailed ocular examination including sequential disc stereo photography. In a randomly chosen eye of a subject whose both eyes met the inclusion criteria, fundus photographs of 2474 ophthalmologically normal eyes of the 2474 subjects were analysed by computer-assisted planimetry to measure the disc, rim and β-peripapillary atrophy (PPA) areas. The rim was divided into the superior and inferior halves by a line connecting the fovea and disc centre.

RESULTS

The disc, superior and inferior halves rim and β-PPA areas averaged 2.53±0.50 (SD), 0.82±0.15, 0.84±0.16 and 0.45±0.66 mm². After adjustment for other systemic and ocular factors including age, disc and β-PPA areas, disc-fovea distance (p=0.013, 0.016) correlated positively and intraocular pressure (IOP) (p=0.004, 0.006) and axial length (AL) (p<0.000, 0.004) negatively with the superior and inferior halves rim area, respectively; central corneal thickness (CCT) (p=0.008) and mean blood pressure (mBP) (p=0.020) correlated positively and male gender (p=0.012) negatively only with the superior half rims.

CONCLUSIONS

Besides previously reported risk factors for glaucoma such as age or IOP, thinner CCT, lower mBP and male gender were newly found to significantly correlate with smaller rim area only in the superior half disc, and a greater disc-fovea distance with greater superior and inferior half rim areas in normal adult eyes.

Glucose Tolerance Levels and Circumpapillary Retinal Nerve Fiber Layer Thickness in a General Japanese Population: The Hisayama Study

PURPOSE

To investigate the relationship between glucose tolerance levels and the circumpapillary retinal nerve fiber layer thickness (cpRNFLT) in a general Japanese population.

DESIGN

Population-based, cross-sectional study.

METHODS

In 2012 and 2013, a total of 2809 Japanese community dwellers aged 40-79 years in the Hisayama Study underwent eye examinations including cpRNFLT measurement with spectral domain optical coherence tomography. Of these, 1324 subjects (578 men and 746 women) were enrolled. Glucose tolerance levels were determined by a 75-g oral glucose tolerance test. We conducted an analysis of covariance to estimate the mean values of cpRNFLT according to the subjects' glucose intolerance status.

RESULTS

The subjects with prediabetes or with diabetes mellitus had significantly lower age- and sex-adjusted mean cpRNFLT values than those with normal glucose tolerance (P = .04 and P = .0004, respectively). The age- and sex-adjusted mean values of cpRNFLT decreased significantly with elevating fasting plasma glucose and 2-hour postload glucose levels (all P for trend < .05). These associations were substantially unchanged after adjustment for potential confounding factors. The coexistence of poorer glucose tolerance and higher intraocular pressure levels was additively associated with thinner cpRNFLT.

CONCLUSIONS

Our analyses revealed that poorer glucose tolerance was significantly associated with the reduction of cpRNFLT in a Japanese general population, suggesting that the loss of neural tissue in the eye begins at the prediabetic stage, and that hyperglycemia may play a role in the reduction of cpRNFLT.

Determinants and Characteristics of Bruch's Membrane Opening and Bruch's Membrane Opening-Minimum Rim Width in a Normal Japanese Population

Purpose

To identify determinants of Bruch's membrane opening (BMO), and BMO-minimum rim width (BMO-MRW) and circumpapillary retinal nerve fiber layer thickness (RNFLT) centered on BMO center and characterize these parameters in a normal Japanese population.

Methods

Spectral-domain optical coherence tomography images of optic nerve head and circumpapillary and macular retina were obtained in 258 eyes of 258 normal Japanese with mean (standard deviation) age of 51.7 (18.2) years. BMO area, BMO-MRW, RNFLT (measured with a 3.5-mm-diameter circle scan) were all acquired and analyzed relative to the eye-specific fovea to BMO (FoBMO) axis. One randomly selected eye of each subject was analyzed. Multiple regression analysis was used to identify determinants to the parameters.

Results

BMO area, global BMO-MRW, RNFLT, and FoBMO angle averaged 2.06 (0.45) mm2, 305.5 (50.0) μm, 101.8 (9.6) μm, and -7.8° (3.8°), respectively. There was a modest correlation between global BMO-MRW and RNFLT (r = 0.337; P < 0.001), while the sectorwise correlations were highest in the superior-temporal sector (r = 0.500; P < 0.001) and lowest in the nasal sector (r = 0.117; P = 0.063). Global BMO-MRW and RNFLT declined with age at -1.04 μm/y (P < 0.001) and -0.12 μm/y (P = 0.001), and the former correlated negatively (P = 0.001) and the latter positively (P < 0.001) with BMO area after adjustment for other factors (R2 = 0.191 and 0.272, respectively). BMO area correlated positively with axial length (P = 0.023) and negatively with age (P < 0.001) (R2 = 0.157).

Conclusions

BMO-MRW and RNFLT declined with age with a difference between them in their relationship to BMO area. BMO area positively correlated with axial length and negatively with age.

Evaluation of Optical Coherence Tomography to Detect Elevated Intracranial Pressure in Children

Importance

Detecting elevated intracranial pressure in children with subacute conditions, such as craniosynostosis or tumor, may enable timely intervention and prevent neurocognitive impairment, but conventional techniques are invasive and often equivocal. Elevated intracranial pressure leads to structural changes in the peripapillary retina. Spectral-domain (SD) optical coherence tomography (OCT) can noninvasively quantify retinal layers to a micron-level resolution.

Objective

To evaluate whether retinal measurements from OCT can serve as an effective surrogate for invasive intracranial pressure measurement.

Design, Setting, and Participants

This cross-sectional study included patients undergoing procedures at the Children's Hospital of Philadelphia from September 2014 to June 2015. Three groups of patients (n = 79) were prospectively enrolled from the Craniofacial Surgery clinic including patients with craniosynostosis (n = 40). The positive control cohort consisted of patients with hydrocephalus and suspected intracranial hypertension (n = 5), and the negative control cohort consisted of otherwise healthy patients undergoing a minor procedure (n = 34).

Main Outcomes and Measures

Spectral-domain OCT was performed preoperatively in all cohorts. Children with cranial pathology, but not negative control patients, underwent direct intraoperative intracranial pressure measurement. The primary outcome was the association between peripapillary retinal OCT parameters and directly measured elevated intracranial pressure.

Results

The mean (SD) age was 34.6 (45.2) months in the craniosynostosis cohort (33% female), 48.9 (83.8) months in the hydrocephalus and suspected intracranial hypertension cohort (60% female), and 59.7 (64.4) months in the healthy cohort (47% female). Intracranial pressure correlated with maximal retinal nerve fiber layer thickness (r = 0.60, P ≤ .001), maximal retinal thickness (r = 0.53, P ≤ .001), and maximal anterior retinal projection (r = 0.53, P = .003). Using cut points derived from the negative control patients, OCT parameters yielded 89% sensitivity (95% CI, 69%-97%) and 62% specificity (95% CI, 41%-79%) for detecting elevated intracranial pressure. The SD-OCT measures had high intereye agreement (intraclass correlation, 0.83-0.93) and high intragrader and intergrader agreement (intraclass correlation ≥0.94). Conventional clinical signs had low sensitivity (11%-42%) for detecting intracranial hypertension.

Conclusions and Relevance

Noninvasive quantitative measures of the peripapillary retinal structure by SD-OCT were correlated with invasively measured intracranial pressure. Optical coherence tomographic parameters showed promise as surrogate, noninvasive measures of intracranial pressure, outperforming other conventional clinical measures. Spectral-domain OCT of the peripapillary region has the potential to advance current treatment paradigms for elevated intracranial pressure in children.

Retinal nerve fiber layer and macular thickness in patients with schizophrenia: Influence of recent illness episodes

Optical coherence tomography (OCT) has been recently used to investigate neuropsychiatric disorders. We aimed to study retinal OCT measures of patients with schizophrenia with respect to healthy controls, and to evaluate possible differences between recent illness episode (RIE) and non-recent illness episode (NRIE) patients. Thirty schizophrenia patients were classified as RIE (n=10) or NRIE (n=20), and compared with 30 matched controls. Statistical analyses included linear mixed-effects models to study the association between OCT measures and group membership. Multivariate models were used to control for potential confounders. In the adjusted linear mixed-effects regression model, patients had a significantly thinner retinal nerve fiber layer (RNFL) in overall measurements, and in the nasal, superior and inferior quadrants. Macular inner ring thickness and macular volume were also significantly smaller in patients than controls. Compared with controls, in the adjusted model only NRIE (but not RIE) patients had significantly reduced RNFL overall measures, superior RNFL, nasal RNFL, macular volume, and macular inner ring thickness. No significant correlation was found between illness duration and retinal measurements after controlling for age. In conclusion, retinal parameters observed using OCT in schizophrenia patients could be related to clinical status and merit attention as potential state biomarkers of the disorder.

Lamina cribrosa defects and optic disc morphology in primary open angle glaucoma with high myopia

Purpose

To investigate whether lamina cribrosa (LC) defects are associated with optic disc morphology in primary open angle glaucoma (POAG) eyes with high myopia.

Methods

A total of 129 POAG patients and 55 age-matched control subjects with high myopia were evaluated. Three-dimensional scan images obtained by swept source optical coherence tomography were used to detect LC defects. Radial B-scans and infrared images obtained by spectral domain optical coherence tomography were used to measure β-peripapillary atrophy (PPA) lengths with and without Bruch's membrane (BM) (temporal, nasal, superior, and inferior), tilt angle (vertical and horizontal), and disc diameter (transverse and longitudinal). Peripapillary intrachoroidal cavitations (PICCs), disc area, ovality index, and cyclotorsion of the optic disc were analyzed as well.

Results

LC defects were found in 70 of 129 (54.2%) POAG eyes and 1 of 55 (1.8%) control eyes (P<0.001). Age, sex, spherical equivalent, axial length, intraocular pressure, and central corneal thickness were not significantly different among POAG eyes with LC defects, POAG eyes without LC defects, and control eyes. Temporal PPA lengths without BM in all three groups correlated significantly with vertical and horizontal tilt angles, although no PPA length with BM correlated significantly with any tilt angle. PICCs were detected more frequently in POAG eyes with LC defects than those without LC defects (P = 0.01) and control eyes (P = 0.02). POAG eyes with LC defects showed a smaller ovality index (P = 0.004), longer temporal PPA without BM (P<0.001), and larger vertical/horizontal tilt angles (vertical, P<0.001; horizontal, P = 0.01), and transverse diameter (P = 0.01). In multivariate analysis for the presence of LC defects, presence of POAG (P<0.001) and vertical tilt angle (P<0.001) were identified as significant.

Conclusions

The presence of LC defects was associated with myopic optic disc morphology in POAG eyes with high myopia.

Laser scanning tomography in the EPIC-Norfolk Eye Study: principal components and associations

PURPOSE

To describe Heidelberg Retina Tomograph (HRT) measures, their principal components, and their associations in a British population.

METHODS

The European Prospective Investigation of Cancer (EPIC)-Norfolk Eye Study is nested within a multicenter cohort study. Measurements were taken with the HRT-2 and the software subsequently updated to yield HRT-3 parameters. Principal components analysis (PCA) was used to identify distinct components of the HRT variables. Generalized estimating equation models were used to examine associations of these components with age, sex, height, body mass index (BMI), blood pressure, social class, education, alcohol intake, smoking status, axial length, IOP, and lens status.

RESULTS

Complete data were available from 10,859 eyes of 6430 participants with a mean age of 68 years. Principal components analysis identified three components with an eigenvalue greater than 1, explaining 79.9% of the variance of all the HRT measures. These were named cup, retinal nerve fiber layer (RNFL), and rim based on the factor loadings they were most correlated with. Older age was significantly associated with a greater cup (P = 0.003), smaller RNFL (P < 0.001), and smaller rim (P < 0.001). Female sex (P = 0.001), higher education (P < 0.001), and shorter axial length (P < 0.001) were associated with a greater RNFL. Lower BMI and higher IOP were associated with a greater cup (both, P < 0.001) and a smaller rim (BMI, P = 0.001; IOP, P < 0.001).

CONCLUSIONS

Heidelberg Retina Tomograph measures in this cohort were largely explained by three principal components related to optic disc cup, RNFL, and rim. Associations with cup and rim were distinct to associations with RNFL, suggesting different underlying determinants.

Myopia-related fundus changes in Singapore adults with high myopia

PURPOSE

To examine the pattern of myopia-related macular and optic disc changes in Singapore adults with high myopia (spherical equivalent ≤-6.00 diopters).

DESIGN

Asian adults with high myopia from 3 population-based surveys.

METHODS

Adults 40 years and older (n = 359) with high myopia were pooled from 3 population-based surveys in Singapore Asians: (1) the Singapore Prospective Study Program (SP2, n = 184); (2) the Singapore Malay Eye Study (SiMES, n = 98); and (3) the Singapore Indian Eye Study (SINDI, n = 77). All study participants underwent standardized refraction and fundus photography, and SiMES and SINDI subjects also completed ocular biometry measurements. Myopia-related macular (posterior staphyloma, lacquer cracks, Fuchs spot, myopic chorioretinal atrophy, and myopic choroidal neovascularization) and optic disc (optic nerve head tilt, optic disc dimensions, and peripapillary atrophy) changes were evaluated.

RESULTS

The most common myopia-related macular finding in adults with high myopia was staphyloma (23%), followed by chorioretinal atrophy (19.3%). There were few cases of lacquer crack (n = 6, 1.8%), T-sign (n = 6, 1.8%), retinal hemorrhage (n = 3, 0.9%), active myopic choroidal neovascularization (n = 3, 0.9%), and no case of Fuchs spot. The most common disc finding associated with high myopia was peripapillary atrophy (81.2%), followed by disc tilt (57.4%). Staphyloma and chorioretinal atrophy increased in prevalence with increasing age, increasing myopic refractive error, and increasing axial length (all P < .001). Ethnicity comparisons demonstrated the highest proportion of staphyloma (P = .04) among Malays, the highest proportion of peripapillary atrophy (P = .01) and disc tilt (P < .001) among Chinese, and the largest cup-to-disc ratio (P < .001) among Indians.

CONCLUSIONS

Staphyloma and chorioretinal atrophy lesions were the most common fundus findings among Asian adults with high myopia. In this population, tilted discs and peripapillary atrophy were also common, while choroidal neovascularization and Fuchs spot were rare. In contrast with Singapore teenagers, in whom tilted disc and peripapillary atrophy were common while staphyloma and chorioretinal atrophy were rare, pathologic myopia appears to be dependent on the duration of disease and, thus, age of the individual.

The relationship between cup-to-disc ratio and estimated number of retinal ganglion cells

PURPOSE

To investigate the relationship between cup-to-disc ratio (CDR) and estimates of retinal ganglion cell (RGC) number.

METHODS

This cross-sectional study included 156 healthy eyes, 53 glaucoma suspects, and 127 eyes with glaucoma. All eyes had standard automated perimetry (SAP), Cirrus SD-OCT, and stereoscopic optic disc photography within 6 months. CDR was determined from stereoscopic photographs by two or more masked graders. The number of RGCs in each eye was estimated using a published model that combines estimates of RGC number from SAP sensitivity thresholds and SD-OCT retinal nerve fiber layer measurements.

RESULTS

The mean estimated RGC count was 1,063,809 in healthy eyes; 828,522 in eyes with suspected glaucoma; and 774,200 in early, 468,568 in moderate, and 218,471 in advanced glaucoma. Healthy eyes had a mean vertical CDR of 0.45 ± 0.15 vs. 0.80 ± 0.16 in glaucomatous eyes. There was good correlation between stereophotographic vertical CDR and SD-OCT vertical CDR (R(2) = 0.825; P < 0.001). The relationship between estimated RGCs and vertical CDR was best represented using a third degree polynomial regression model, including age and optic disc area, which accounted for 83.3% of the variation in estimated RGC counts. The nonlinear relationship between RGC estimates and CDRs indicated that eyes with a large CDR would require loss of large RGC numbers for a small increase in CDR.

CONCLUSIONS

The relationship between estimated RGC counts and CDR suggests that assessment of change in CDR is an insensitive method for evaluation of progressive neural losses in glaucoma. Even relatively small changes in CDR may be associated with large losses of RGCs, especially in eyes with large CDRs. (ClinicalTrials.gov numbers, NCT00221923, NCT00221897.).

Biometry and spectral domain optical coherence tomography parameters in children with large cupping

PURPOSE

The purpose of this study is to investigate optic nerve head using spectral domain optical coherence tomography (SD-OCT) in children with large cupping.

METHODS

111 eyes (4-10 years) were divided into three groups according to the cup to disc ratio: group 1, ≤0.3; group 2, 0.4-0.6; and group 3, ≥0.7. The rim area, disc area, average cup to disc ratio, vertical cup to disc ratio, and cup volume were investigated using SD-OCT (Cirrus HD-OCT, Carl Zeiss, Jena, Germany), and the axial length and anterior chamber depth (ACD) were measured by IOL master (IOL master 500, Carl Zeiss, Jena, Germany). Next, we compared ocular biometry and SD-OCT between the three groups.

RESULTS

The mean age of group 1 was 6.48 ± 1.42 years, 7.00 ± 1.75 years in group 2, and 6.63 ± 1.82 years in group 3 (p = 0.370). A significant difference was seen in the spherical equivalent between the groups (p = 0.001). Group 2 had the most myopic refractive errors. As the cup to disc ratio increases, disc area, average cup to disc ratio, vertical cup to disc ratio, and cup volume increase significantly. When the results of ocular biometry and SD-OCT are adjusted for axial length, only disc area showed a significant correlation with cup to disc ratio (ACD: p = 0.473, rim area: p = 0.639, disc area: p = 0.005, and cup volume: p = 0.325).

CONCLUSION

Axial length is the key factor determining disc size, which in turn is important for determining cup to disc ratio. Normal children with large cupping should be examined for axial length, myopic refractive errors, and disc size.