Vertical Cup-disc Ratio Research Articles

Optic disc hemorrhages in glaucoma and common clinical features.

To analyze optic nerve head stereophotographs for the presence of optic disc hemorrhages, and to describe bleeding patterns and patient characteristics. Retrospective, cross-sectional study. 1113 optic nerve stereophotograph pairs of 562 consecutive patients. Stereophotographs were systematically reviewed for the presence of a disc hemorrhage with careful documentation of optic nerve head features. All charts of patients with hemorrhage were subsequently studied for demographic information and clinical data. Disc hemorrhages were observed in 7.1% of patients with optic disc photography. Most patients had open-angle glaucoma (57.5%) with focal ischemic phenotype of the optic disc (66.7%). The mean vertical and horizontal cup-disc ratios were 0.82 ± 0.14 and 0.76 ± 0.14, respectively. The β-zone peripapillary atrophy was observed in 48.9% of patients. The most common location was the inferotemporal region of the disc (60.8%), and most were flame or splinter shaped (70.6%). Disc hemorrhages were found either superficial to or within the retinal nerve fibre layer (72.5%), and in association with a notch (64.4%). The average intraocular pressure was 17.3 ± 4.9 mm Hg, and most hemorrhages were associated with early visual field defects (42.5%). Optic disc hemorrhages in patients with glaucoma were most frequently observed inferiorly in association with a notch. Most eyes with a disc hemorrhage had an intraocular pressure within normal range and had either early or no visual field loss. These findings highlight the importance of careful examination of the optic nerve head to look for the presence of a disc hemorrhage as an important biomarker of glaucoma damage.

Haplotype reference consortium panel: Practical implications of imputations with large reference panels.

Recently, the Haplotype Reference Consortium (HRC) released a large imputation panel that allows more accurate imputation of genetic variants. In this study, we compared a set of directly assayed common and rare variants from an exome array to imputed genotypes, that is, 1000 genomes project (1000GP) and HRC. We showed that imputation using the HRC panel improved the concordance between assayed and imputed genotypes at common, and especially, low-frequency variants. Furthermore, we performed a genome-wide association meta-analysis of vertical cup-disc ratio, a highly heritable endophenotype of glaucoma, in four cohorts using 1000GP and HRC imputations. We compared the results of the meta-analysis using 1000GP to the meta-analysis results using HRC. Overall, we found that using HRC imputation significantly improved P values (P=3.07×10-61 ), particularly for suggestive variants. Both meta-analyses were performed in the same sample size, yet we found eight genome-wide significant loci in the HRC-based meta-analysis versus seven genome-wide significant loci in the 1000GP-based meta-analysis. This study provides supporting evidence of the new avenues for gene discovery and fine mapping that the HRC imputation panel offers.

An Observational Study Comparing the Correlation of Vertical Cup Disc Ratio and Disc Damage Likelihood Scale with Visual Field Changes and Central Corneal Thickness in Primary Open Angle Glaucoma Patients

An Observational Study Comparing the Correlation of Vertical Cup Disc Ratio and Disc Damage Likelihood Scale with Visual Field Changes and Central Corneal Thickness in Primary Open Angle Glaucoma Patients

Association of Plasma Complement C3 Levels With Primary Angle-Closure Glaucoma in Older Women.

The plasma complement component (C)3 concentration and clinical characteristics of primary angle-closure glaucoma (PACG) subjects were analyzed to evaluate whether C3 levels were correlated with PACG severity. Peripheral blood samples from subjects with PACG (n = 237) and normal controls (n = 158) were collected. The plasma levels of C3 were measured by immunoturbidimetry. The assessments of intraocular pressure; vertical cup/disc ratio (VCDR); central corneal thickness; axial length; anterior chamber depth; visual field-derived mean deviation; and mean sensitivity were performed by glaucoma specialists. Based on their sex and age, the PACG subjects were categorized into female (0-49 years, 50-59 years, 60-70 years, and 70+ years) and male (0-49 years, 50-59 years, 60-70 years, and 70+ years) subgroups. The mean plasma levels of C3 (101.71 ± 21.17 mg/dL) were significantly lower (P < 0.001) in PACG subjects compared with controls (110.68 ± 17.63 mg/dL). Plasma C3 concentrations were significantly lower (P < 0.001) in female subjects with PACG (100.74 ± 19.83 mg/dL) compared with controls (113.58 ± 18.80 mg/dL). A similar result was observed when plasma levels of C3 were compared between the PACG and control groups with respect to age (≥50 years). The mean plasma levels of C3 were lowest in the severe PACG group followed by moderate PACG and mild PACG, and the differences were significant (P = 0.003). Multivariable regression analyses showed that there was a significant correlation between C3 levels and VCDR (B = -0.310, P = 0.047). Older women with PACG have lower plasma C3 levels, which were further demonstrated to be negatively associated with PACG severity. These findings suggest the involvement of C3 in the pathomechanisms of PACG in older women.

Neuroprotection for treatment of glaucoma in adults.

Glaucoma is a heterogeneous group of conditions involving progressive damage to the optic nerve, deterioration of retinal ganglion cells, and ultimately visual field loss. It is a leading cause of blindness worldwide.Open angle glaucoma (OAG), the most common form of glaucoma, is a chronic condition that may or may not present with increased intraocular pressure (IOP). Neuroprotection for glaucoma refers to any intervention intended to prevent optic nerve damage or cell death. The objective of this review was to systematically examine the evidence regarding the effectiveness of neuroprotective agents for slowing the progression of OAG in adults compared with no neuroprotective agent, placebo, or other glaucoma treatment. We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 7), Ovid MEDLINE, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily (January 1946 to August 2016), Embase (January 1980 to August 2016), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to August 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 16 August 2016. We included randomised controlled trials (RCTs) in which topical or oral treatments were used for neuroprotection in adults with OAG.Minimum follow-up time was four years. Two review authors independently reviewed titles and abstracts from the literature searches. We obtained full-text copies of potentially relevant studies and re-evaluated for inclusion. Two review authors independently extracted data related to study characteristics, risk of bias, and outcomes. We identified one trial for this review, thus we performed no meta-analysis. Two studies comparing memantine to placebo are currently awaiting classification until study investigators provide additional study details. We documented reasons for excluding studies from the review. We included one multicenter RCT of adults with low-pressure glaucoma (Low-pressure Glaucoma Treatment Study, LoGTS) conducted in the USA. The primary outcome was progression of visual field loss after four years of treatment with either brimonidine or timolol. Of the 190 adults enrolled in the study, the investigators excluded 12 (6.3%) after randomization; 77 participants (40.5%) did not complete four years of follow-up. The rate of attrition was unbalanced between groups with more participants dropping out of the brimonidine group (55%) than the timolol group (29%).Of those remaining in the study at four years, participants assigned to brimonidine showed less progression of visual field loss than participants assigned to timolol (risk ratio (RR) 0.35, 95% confidence interval (CI) 0.14 to 0.86; 101 participants). Because of high risk of attrition bias and potential selective outcome reporting, we graded the certainty of evidence for this outcome as very low. At the four-year follow-up, the mean IOP was similar in both groups among those for whom data were available (mean difference 0.20 mmHg, 95% CI -0.73 to 1.13; 91 participants; very low-certainty evidence). The study authors did not report analyzable data for visual acuity or any data related to vertical cup-disc ratio, quality of life, or economic outcomes. The most frequent adverse event was ocular allergy to the study drug, which affected more participants in the brimonidine group than the timolol group (RR 5.32, 95% CI 1.64 to 17.26; 178 participants; very low-certainty evidence). Although the only trial we included in this review found less visual field loss in the brimonidine-treated group, the evidence was of such low certainty that we can draw no conclusions from this finding.Further clinical research is needed to determine whether neuroprotective agents may be beneficial for individuals with OAG. Such research should focus on outcomes important to patients, such as preservation of vision, and how these outcomes relate to cell death and optic nerve damage. As OAG is a chronic, progressive disease with variability in symptoms, RCTs designed to measure the effectiveness of neuroprotective agents require a long-term follow-up of five years or longer to detect clinically meaningful effects.

New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics.

Primary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increased risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a genome-wide association meta-analysis of IOP and optic disc parameters and validated our findings in multiple sets of POAG cases and controls. Using imputation to the 1000 genomes (1000G) reference set, we identified 9 new genomic regions associated with vertical cup-disc ratio (VCDR) and 1 new region associated with IOP. Additionally, we found 5 novel loci for optic nerve cup area and 6 for disc area. Previously it was assumed that genetic variation influenced POAG either through IOP or via changes to the optic nerve head; here we present evidence that some genomic regions affect both IOP and the disc parameters. We characterized the effect of the novel loci through pathway analysis and found that pathways involved are not entirely distinct as assumed so far. Further, we identified a novel association between CDKN1A and POAG. Using a zebrafish model we show that six6b (associated with POAG and optic nerve head variation) alters the expression of cdkn1a. In summary, we have identified several novel genes influencing the major clinical risk predictors of POAG and showed that genetic variation in CDKN1A is important in POAG risk.

A Genome-Wide Association Study of Vertical Cup-Disc Ratio in a Latino Population.

PurposeVertical cup-disc ratio (VCDR) is used as a clinical assessment measure to identify and monitor glaucomatous damage to the optic nerve. Previous genetic studies conducted in European and Asian populations have identified many loci associated with VCDR. The genetic factors in other ethnic populations, such as Latino, influencing VCDR remain to be determined. Here, we describe the first genome-wide association study (GWAS) on VCDR in Latino individuals.MethodsWe conducted this GWAS on VCDR using 4537 Latino individuals who were genotyped by using either the Illumina OmniExpress BeadChip (∼730K markers) or the Illumina Hispanic/SOL BeadChip (∼2.5 million markers). Study subjects were 40 years of age and older. Linear regression, adjusting for age, sex, and principal components of genetic ancestry, was conducted to assess the associations between single nucleotide polymorphisms (SNPs) and VCDR. We imputed SNPs from the 1000 Genomes Project to integrate additional SNPs not directly genotyped.ResultsWe replicated two previously reported SNPs that reached GWAS significance, rs1900005 and rs7916697, in the ATOH7-PBLD region, as well as identified two suggestive associations in the CDC7-TGFBR3 region on chromosome 1p22.1 and in the ZNF770-DPH6 region on chromosome 15q14. We discovered a novel SNP, rs56238729 (P = 1.22 × 10−13), in the ATOH7-PBLD region that is significantly associated with VCDR in Latino individuals. We replicated eight previously reported regions, including COL8A1, CDKN2B-CDKN2BAS, BMP2, and CHEK2 (P < 2.17 × 10−3).ConclusionsOur results discovered a novel SNP that is significantly associated with VCDR in Latino individuals and confirmed previously reported loci, providing further insight into the genetic architecture of VCDR.

Interocular symmetry of retinal nerve fiber layer and optic nerve head parameters measured by Cirrus high-definition optical coherence tomography in a normal pediatric population.

Purpose:To determine interocular differences in the retinal nerve fiber layer (RNFL) and optic nerve head (ONH) parameters in a pediatric population using Cirrus high-definition optical coherence tomography (HD-OCT).Methods:Seventy normal Indian children aged 5–17 years presenting to the Pediatric Clinic were included in this observational cross-sectional study. All subjects underwent a comprehensive ophthalmologic examination and an evaluation of the RNFL and ONH by Cirrus HD-OCT. Differences between the right and left eyes were calculated and values were compared by means of a paired t-test. Subjects were also divided into two groups based on age (under or over 10 years of age). Interocular differences in RNFL and ONH parameters together with sex and age variations for these differences were determined.Results:The mean age of studied pediatric population was 11.83 ± 3.3 years (range 5–17). Average RNFL thickness was 94.46 ± 8.7 μm (± SD) (range 77–111). Differences in the average RNFL between right and left eyes were not statistically significant (P = 0.060). Superior quadrant RNFL was thicker in the left eye and temporal quadrant was thicker in the right eye. Among ONH parameters, there were no statistically significant differences in any parameters, except vertical cup-disc (CD) ratio which was significant (P = 0.007). The 2.5%–97.5% limits of asymmetry were 9 μm for average RNFL, 0.14 for average CD ratio, and 0.22 for vertical CD ratio. Mean interocular RNFL thickness differences in superior, superior nasal, and temporal superior quadrants were 10.61 (P < 0.001), 12.57 (P < 0.001), and 4.46 (P = 0.002) μm, respectively. Interocular nerve fiber layer thickness differences were not significantly correlated with sex, while only significant differences with age were observed in 12 clock hour sector analysis, mainly in nasal inferior and inferior quadrant.Conclusions:We report the degree of interocular symmetry of RNFL and ONH parameters measured by Cirrus HD-OCT in a healthy pediatric population. The normal interocular RNFL asymmetry should not exceed 9 μm and vertical CD ratio beyond 0.22 should be considered for further investigations. The physiologic asymmetry provided by this study may assist in identifying changes in RNFL thickness and ONH parameters in pediatric glaucoma and ONH disorders.

Effect of phacoemulsification on measurement of retinal nerve fiber layer and optic nerve head parameters using spectral-domain-optical coherence tomography.

PURPOSE:The purpose of this study is to determine the effect of phacoemulsification cataract extraction on measurement of retinal nerve fiber layer and optic nerve head parameters using spectral domain optical coherence tomography.MATERIAL AND METHODS:A prospective, hospital-based study of 100 patients of 40 years of age and above, with no other ocular morbidity except cataract and planned for phacoemulsification with IOL implantation (SN60WF) at a tertiary centre at AIIMS, New Delhi, India. All patients underwent imaging with Cirrus SD-OCT model 400 and the optic disc cube 200x200 protocol at baseline and at 1 month follow up. Paired sample t-test was used to compare the RNFL parameters and ONH parameters.RESULTS:The mean age of subjects was 56.6 ± 12.3 years (70 males, 30 females). The average RNFL increased from 92.6 ± 5.4 μm to 101.3 ± 5.6 μm after phacoemulsification, an increase of 9% (P = 0.003) and the signal strength increased from 5.6 ± 0.5 to 7.6 ± 0.7, increasing by 35.7% (P = 0.004). There was a significant increase in the disc area (P = 0.004) and rim area (P = 0.004) but no significant change in vertical cup-disc ratio (P = 0.45) or average cup-disc ratio (P = 0.075). The quadrant-wise RNFL thickness increase in inferior, superior, nasal, and temporal quadrants was 12.6% (P = 0.001), 10% (P = 0.001), 5.6% (P = 0.001), and 3.2% (P = 0.001), respectively. The change in RNFL thickness was maximum in posterior subcapsular cataract (P = 0.001) followed by cortical (P = 0.001) and nuclear (P = 0.001) subtypes.CONCLUSIONS:A significant increase in RNFL thickness and signal strength was observed after cataract surgery using SD-OCT. The maximum change in RNFL thickness was in the inferior quadrant, where RNFL thinning is a significant predictor of glaucoma progression. The posterior subcapsular cataract interfered with RNFL measurement maximally due to its density and proximity to nodal point. After the cataract surgery, a new baseline needs to be established by obtaining fresh OCT images for assessing the longitudinal follow-up of a glaucoma patient.

Comparison of vertical cup-disc ratio and disc damage likelihood scale with respect to visual field global indices in primary open-angle glaucoma patients: A cross-sectional study

Background: In primary open-angle glaucoma (POAG), structural changes in optic nerve head precede functional changes in visual field (VF). Hence, it is important to detect glaucoma early as well as to monitor changes in glaucomatous damage. Aims: The aim of this study was to determine the correlation between each of vertical cup/disc ratio (VCDR) and the disc damage likelihood scale (DDLS) with global indices of Humphrey Field Analyzer II (HFA II). Methods: A total of 142 eyes of 71 patients diagnosed with POAG who fulfilled the inclusion and exclusion criteria were examined to grade DDLS score VCDR. HFA II Swedish Interactive Threshold Algorithm Standard 24-2 VFs were obtained. Statistical Analysis: The correlation of cup/disc (C/D) ratio with mean deviation (MD) and pattern standard deviation (PSD) was calculated by Spearman's correlation coefficient. Similar coefficients were obtained for DDLS also. Correlation values of selected variables were compared to find the difference in correlations. Results: DDLS shows strong negative correlation with MD (− 0.725) and strong positive correlation (0.625) with PSD when compared to C/D ratio. However, the differences between these correlations were not statistically significant. Conclusion: The DDLS shows stronger correlation with VF global indices than C/D ratio. Attention to disc diameter and rim width may increase the value of clinical optic disc examination

The association between serum uric acid and glaucoma severity in primary angle closure glaucoma: a retrospective case-control study.

Uric acid (UA) is a major antioxidant molecule and has been hypothesized to have a protective effect on the central nervous system against oxidative damage. We prospectively investigated the serum concentration of UA in primary angle closure glaucoma (PACG), and explored the association between serum concentration of UA and the severity of PACG. Using a retrospective case-control study design, 886 PACG subjects and 994 control subjects who attended the Eye & ENT Hospital of Fudan University, were eligible for this study. Glaucoma severity was classified as mild (MD ≤ 6.00 dB), moderate (12 dB ≥ MD > 6 dB) and severe (MD > 12 dB) based on the MD (mean deviation). The levels of UA were significantly lower (p = 0.025) in PACG (0.286 ± 0.082 mmol/l) compared with control (0.295 ± 0.085 mmol/l). The mean serum UA levels were lowest in the severe group (0.281 ± 0.074 mmol/l) followed by moderate (0.282 ± 0.080 mmol/l) and mild (0.297 ± 0.090 mmol/l) with significant differences among the three groups (p = 0.032). In multivariate regression analysis, there was a significant negative correlation between UA level and vertical cup-disc ratio (B = −0.165, p = 0.035). Significantly lower serum UA concentration in PACG and its negative association with disease severity presented it as an important candidate in reaction to oxidative stress in glaucoma pathogenesis.

Funduscopic versus HRT III Confocal Scanner Vertical Cup-Disc Ratio Assessment in Normal Tension and Primary Open Angle Glaucoma (The Leuven Eye Study)

Purpose: To compare funduscopic and confocal scanning vertical cup-disc ratio (VCDR) assessments and their respective predictive value for estimating functional glaucomatous damage. Methods: Data from a single eye of open angle glaucoma patients from the Leuven Eye Study were included: age, gender, intra-ocular pressure, visual acuity, refractive error, visual field mean deviation and pattern standard deviation, funduscopic and HRT III VCDRs as well as mean retinal nerve fibre layer thickness. Non-parametric tests to compare differences within and between diagnostic groups were used, and receiver-operating characteristic curves as well as Bland-Altman plots constructed. Results: Three hundred and one eyes of 301 subjects with primary open angle glaucoma (POAG) and normal tension glaucoma (NTG) were included. The average VCDR assessed with HRT III was significantly smaller than the funduscopic measurement (0.69 ± 0.16 vs. 0.81 ± 0.14, respectively; p < 0.001). The predictive value of both measurement techniques did not differ in NTG patients, but the funduscopic estimate yielded a significantly larger predictive power in patients with severe POAG. Conclusion: Funduscopic and confocal scanner estimates of VCDR differ significantly and should not be used interchangeably. In POAG patients with severe glaucoma, a subjective VCDR predicts functional glaucomatous damage significantly better.

Evaluation of Macular Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer in Primary Craniopharyngioma by Fourier-Domain Optical Coherence Tomography

BackgroundThe aim of this study was to compare the differences in macular ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (pRNFL) in child and adult patients with primary craniopharyngioma by Fourier-domain optical coherence tomography (FD-OCT) and to evaluate their significance in the diagnosis of primary craniopharyngioma.Material/MethodsNinety-six participants were divided into 3 groups: 32 in the child craniopharyngioma group (CCG) and 32 in the adult craniopharyngioma group (ACG) who were treated in Beijing Tiantan Hospital between November 2013 and October 2014, and 32 in the normal group (NG). All subjects were scanned by FD-OCT to map GCC and pRNFL thicknesses. Spearman correlation coefficient was used to assess the correlation between GCC and pRNFL thickness, and pRNFL thickness and optic nerve head (ONH) parameters, including horizontal cup-disc ratio (HCDR), vertical cup-disc ratio (VCDR), optic disc area (ODA), and cup area (CA), respectively.ResultsThe correlation between GCC and pRNFL thickness in the CCG was slightly stronger compared with the ACG. A significant difference in GCC thickness was observed among the CCG, ACG, and NG. Although the pRNFL thickness in both the CCG and ACG was significantly higher than that in NG, no significant difference in pRNFL thickness was detected between the 2 craniopharyngioma groups. The average, superior, and inferior pRNFL thicknesses were negatively correlated with VCDR in the CCG (in double eyes) and ACG (only in left eyes).ConclusionsGCC was more sensitive than pRNFL in detecting optic nerve damage in the eyes of craniopharyngioma patients. A thinner pRNFL was especially correlated with VCDR in child craniopharyngioma patients.

Comparison of Peripapillary Retinal Nerve Fiber Layer (RNFL) Thickness between the Normal and Glaucoma Eyes with the Same Vertical Cup Disc Ratio (CDR) using Optical Coherence Tomography (OCT)

Background: Glaucoma is a disease that belongs to a group of neurodegenerative diseases, such as impaired visual field and optic neuropathy with progressive damage to the optic nerve and retinal nerve fiber layer (RNFL) which is caused by the loss of ganglion cells and axon of the optic. Changes in the optic nerve and RNFL may occur prior to the abnormalities of the visual field nerves. Currently, the visual field examination should be performed to diagnose glaucoma but with patient-subjective result. Before it is detectable, visual field abnormalities are likely going to lose its ganglion cells by 40%. The purpose of this study was to assess and compare the peripapillary retinal nerve fiber layer (RNFL) between the normal and glaucoma eyes with vertical cup disc ratio (CDR) 0.4 to 0.7 in eye clinic Cipto Mangunkusumo Hospital (RSCM) Kirana. Methods: A total of 40 eyes of normal group and 34 eyes of glaucoma following Humphrey field analyzer examination and Optical Coherence Tomography (OCT) were evaluated. Peripapillary RNFL thickness between normal and glaucoma eyes were analyzed and compared each other. Eyes of glaucoma group then were grouped into early-stage glaucoma, according to the criteria in the initial stages of the examination results of Humphrey field analyzer. Result of peripapillary RNFL thickness was analyzed to get a cut off value. Results: Peripapillary RNFL thickness in the normal group with vertical CDR 0.4 to 0.7 was 111.3±9.8 μm to 118.0±3.0 μm, and glaucoma groups with vertical CDR 0.4 to 0.7 was 105.6±12.6 μm to 113.7±6.1 μm. Retinal nerve fiber layer thickness in normal group compared to glaucoma group in the superior quadrant, inferior, nasal, temporal and average on CDR 0.4 to 0.7 was not statistically significant (p&gt;0.05), except on vertical CDR 0.6 average peripapillary RNFL (p&lt;0.05). Cut off value of peripapillary RNFL in superior quadrant was 164 μm, inferior 169.5 μm, nasal 82.5 μm, temporal 73.5 μm and average 111.8 μm. Conclusion: There was no difference in changes of peripapillary RNFL along with the progression of vertical CDR but clinically, peripapillary RFNL thickness in glaucoma group is thinner than that of normal group with the same vertical CDR except in temporal quadrant. Keywords: Retinal nerve fiber layer (RNFL), cup disc ratio (CDR), optical coherence tomography (OCT)

Structural Differences in the Optic Nerve Head of Glaucoma Patients With and Without Disc Hemorrhages.

The aim of the study was to evaluate differences in planimetry, optic nerve parameters, and visual field (VF) indices in glaucomatous eyes with a disc hemorrhage (DH), their contralateral counterparts without DH, and normal controls. We retrospectively reviewed the records (from 1995 to 2013) of 44 glaucoma subjects with unilateral DH and 50 normal controls. In the DH group, 33 had bilateral fundus photos for planimetric analysis (Cyoptique GL), 15 had spectral domain-optical coherence tomography (SD-OCT), 15 had VF indices (Humphrey Visual Field Analyser), and 39 had ≥ 5 perimetry outputs for progression analysis (Progressor). Structurally, planimetric analysis revealed that the eye with DH had a larger cup-disc ratio, more significantly in the vertical aspect (P<0.001), and a thinner rim (P=0.010), compared with the contralateral eye without DH. SD-OCT analysis also showed a thinner rim area (P<0.001), most significantly in 2, 3, and 9 clock hours and the inferior and superior quadrants (P<0.001) compared with the contralateral eye without DH and normal controls. Also, the vertical cup-disc ratio was larger (P<0.001). Functionally, VF deterioration was demonstrated by VF indices in eyes with DH-mean deviation: -10.69 versus -0.97, P<0.001 and pattern standard deviation: 6.60 versus 1.59, P<0.001, compared with normal controls. Eyes with DH consistently displayed both structural features of more advanced glaucoma confirmed simultaneously on planimetry and SD-OCT, with concurrent VF deterioration.

Clinical Validation of a Smartphone-Based Adapter for Optic Disc Imaging in Kenya.

Visualization and interpretation of the optic nerve and retina are essential parts of most physical examinations. To design and validate a smartphone-based retinal adapter enabling image capture and remote grading of the retina. This validation study compared the grading of optic nerves from smartphone images with those of a digital retinal camera. Both image sets were independently graded at Moorfields Eye Hospital Reading Centre. Nested within the 6-year follow-up (January 7, 2013, to March 12, 2014) of the Nakuru Eye Disease Cohort in Kenya, 1460 adults (2920 eyes) 55 years and older were recruited consecutively from the study. A subset of 100 optic disc images from both methods were further used to validate a grading app for the optic nerves. Data analysis was performed April 7 to April 12, 2015. Vertical cup-disc ratio for each test was compared in terms of agreement (Bland-Altman and weighted κ) and test-retest variability. A total of 2152 optic nerve images were available from both methods (also 371 from the reference camera but not the smartphone, 170 from the smartphone but not the reference camera, and 227 from neither the reference camera nor the smartphone). Bland-Altman analysis revealed a mean difference of 0.02 (95% CI, -0.21 to 0.17) and a weighted κ coefficient of 0.69 (excellent agreement). The grades of an experienced retinal photographer were compared with those of a lay photographer (no health care experience before the study), and no observable difference in image acquisition quality was found. Nonclinical photographers using the low-cost smartphone adapter were able to acquire optic nerve images at a standard that enabled independent remote grading of the images comparable to those acquired using a desktop retinal camera operated by an ophthalmic assistant. The potential for task shifting and the detection of avoidable causes of blindness in the most at-risk communities makes this an attractive public health intervention.

An Updated Review on the Genetics of Primary Open Angle Glaucoma.

Epidemiological studies suggest that by 2020 the prevalence of primary open angle glaucoma (POAG) is estimated to increase to 76.0 million, and to 111.8 million by 2040 globally due to the population aging. The prevalence of POAG is the highest among those of African descent, followed by Asians, and the lowest in Europeans. POAG is a genetically complex trait with a substantial fraction exhibiting a significant heritability. Less than 10% of POAG cases in the general population are caused by specific gene mutations and the remaining cases are polygenic. Quantitative traits related to POAG pathogenesis such as intra-ocular pressure (IOP), vertical cup/disc ratio (VCDR), optic disc area, and central corneal thickness (CCT) are highly heritable, and likely to be influenced at least in part by genes and show substantial variation in human populations. Recent genome-wide association studies (GWAS) have identified several single nucleotide polymorphisms (SNPs) at different loci including CAV1/CAV2, TMCO1, CDKN2B-AS1, CDC7-TGFBR3, SIX1/SIX6, GAS7 and ATOH7 to be associated with POAG and its related quantitative traits (endophenotypes). The chapter provides a brief overview on the different GWAS and SNP association studies and their correlation with various clinical parameters important for POAG in the population worldwide, including the Middle East.

Optic disc morphology in unilateral branch retinal vein occlusion using spectral domain optical coherence tomography.

BackgroundThe aim of this study was to evaluate the association between optic nerve head (ONH) parameters and branch retinal vein occlusion (BRVO) using spectral domain optical coherence tomography (SD-OCT).MethodsBoth eyes of 40 patients with unilateral BRVO (mean age: 67.4 ± 11.4 years, male: female - 18:22) were enrolled in this study. Control group consisted of randomly selected single healthy eyes of 40 age and gender matched volunteers (mean age: 64.7 ± 15.4 years, male: female - 16:24). ONH parameters (including optic disc area, optic cup area, neuroretinal rim area, cup volume, rim volume, cup-disc area ratio, horizontal and vertical cup-disc ratio, average retinal nerve fiber layer) were measured by SD-OCT. Axial length (AL) of the eyes was measured by non-contact optical low coherence reflectometry. The ONH parameters of eyes with BRVO were compared with those of fellow eyes using mixed model, one-way between-groups analysis of covariance was conducted to compare the ONH parameters of affected and unaffected fellow eyes in BRVO patients with those of the control eyes keeping confounding factors, including AL, age and gender under control in the statistical analysis.ResultsNone of the investigated ONH parameters of affected BRVO eyes, unaffected fellow eyes and control eyes were statistically different after controlling for AL, age and gender.ConclusionOptic disc morphology might not be a potential anatomical predisposing factor for development of BRVO.Electronic supplementary materialThe online version of this article (doi:10.1186/s12886-015-0165-1) contains supplementary material, which is available to authorized users.

Lack of Association Between Corneal Hysteresis and Corneal Resistance Factor With Glaucoma Severity in Primary Angle Closure Glaucoma.

We investigated the association between corneal hysteresis (CH) and corneal resistance factor (CRF) with glaucoma severity in primary angle closure glaucoma (PACG). We recruited 204 subjects with PACG. Each subject underwent CH and CRF measurements using the Ocular Response Analyzer (ORA), optic nerve head topography measurement using scanning laser ophthalmoscopy, and visual field assessment. Glaucoma severity was based on the visual field mean deviation (MD) and classified as mild (71), moderate (55), and severe (78). The mean age ± SD of study subjects was 68.7 ± 8.9 years, with most being Chinese (n = 186; 91.2%). Corneal hysteresis and CRF were lowest in the severe PACG group (9.32 ± 1.86 and 9.50 ± 1.67 mm Hg) followed by moderate PACG (9.38 ± 1.88 and 9.73 ± 1.88 mm Hg) and mild PACG (9.47 ± 1.90 and 9.85 ± 1.75 mm Hg) respectively, but the differences were not significant (P = 0.89 and P = 0.46, respectively). There was a significant positive correlation between CH and central corneal thickness (CCT; correlation coefficient [r] = 0.26, P < 0.001), CRF and CCT (r = 0.43, P < 0.001), and negative correlation between CRF and vertical cup-disc ratio (VCDR; r = -0.20, P = 0.004), and CRF with cup-disc area (r = -0.14, P = 0.04). Corneal hysteresis and CRF were not correlated with MD (r = 0.01 for CH, r = 0.1 for CRF). After multivariate analyses, adjusting for age, sex, CCT, axial length, intraocular pressure, and number of glaucoma medication, no significant associations were noted between CH and CRF with MD, VCDR, disc area, rim area, or cup area. Corneal biomechanical parameters measured by the ORA are not associated with severity of glaucoma in PACG.

Effect of form-deprivation myopia on optic nerve head and retinal morphology in guinea pigs

Objective To evaluate the effect of form deprivation myopia on optic nerve head and retinal morphology in guinea pigs using optical coherence tomography (OCT). Methods Twenty guinea pigs aged from 4 to 5 weeks were chosen and randomly divided into the experimental group and control group, with 10 guinea pigs in each group. Form deprivation myopia was established for the right eyes of guinea pigs in experimental group for 4 weeks. The guinea pigs of control group were not intervened. Before and 4 weeks after form deprivation, refraction was measured by retinoscopy after cycloplegia; the axial length was measured by A-scan ultrasound; retinal nerve fiber layer (RNFL) thickness, optic nerve head and retinal morphology of guinea pigs were analyzed using OCT. Results Before form deprivation, there were no statistically significant differences in spherical equivalent, axial length, RNFL thickness, disc edge area, optic disc area, average cup disc ratio, vertical cup disc ratio, cup volume, retinal thickness, or retinal volume between the experimental group and control group of guinea pig (P>0.05). After 4 weeks of form deprivation, RNFL thickness of (64.9±17.7) μm in guinea pigs in experimental group was thinner compared to (97.9±25.1) μm in control group (t=-2.845, P=0.015). Retinal thickness of (142.7±3.4) μm in guinea pigs in experimental group was thicker compared to (138.4±3.5) μm in control group (t=2.338, P=0.038). There were no significant differences in disc edge area, optic disc area, average cup disc ratio, vertical cup disc ratio, cup volume or retinal volume between groups (P>0.05). There were statistically significant differences in spherical equivalent, axial length, RNFL thickness, vertical cup to disc ratio cup volume, and retinal thickness between after and before form deprivation in the right eye of guinea pigs in the experimental groups (t=46.001, -50.119, 5.385, 3.447, -2.814, -8.911; P 0.05). Conclusion Form deprivation myopia has an effect on RNFL and retinal thickness. Key words: Myopia/complications; Optic disk/physiopathology; Retina/physiopathology; Animal experimentation