of retina and optic nerve head (ONH). 6 Speci ﬁ c algorithms 7 implemented in OCTA devices provide visualization of the capillary network distributed in the retinal nerve ﬁ ber layer (RNFL). Quantitative analysis of the radial peripapillary capillaries (RPC) density can be delivered with high repeat- ability and reproducibility. 8 The RPC network 9 has recently emerged as a promising area in glaucoma diagnosis, man- agement and research. Many investigators showed that OCTA parameters as vessel density or blood ﬂ ow index of the RPC were reduced in glaucomatous eyes compared with normal eyes. 10–19 Several studies demonstrated a strong relationship between extent of RPC drop out and severity of glaucomatous damage. 13,17–23 A spatial correlation among RNFL defects, capillary attenuation and visual ﬁ eld loss has been found. 11,14,24,25 RPC density showed a signi ﬁ cant diagnostic ability to differentiate normal from glaucoma eyes, comparable to that of OCT. 13,22,26,27 It has also been reported that peripapillary microvascular changes may precede vision ﬁ eld loss. 11,12,19,27–30 The preperimetric stage of glaucoma, de ﬁ ned as nerve ﬁ ber damage without detectable defects in standard automated perimetry (SAP), remains a challenging diagnosis which could be facilitated by OCTA. However, it is still under discussion whether the assessment of RPC density could help in preperimetric glaucoma (PPG) detection. 13,15,20,26–31 The aim of the pre- sent study was to investigate the vascular status of the optic disc and peripapillary area in association with the structural changes in patients with unilateral PPG.
AL: axial length; AUROC: area under the receiver operating characteristic curves; C/D, VF: visual field; cup-to-disc ratio; CCT: central corneal thickness; CI: confidence interval; cpRNFL: circumferential peripapillary retinal nerve fiber layer; D: diopters; GCIPL: ganglion cell-inner plexiform layer; I: inferior hemisphere; IN: inferonasal; IOP: intraocular pressure; IT: inferotemporal; MD: mean deviation; N: nasal; OCT: optical coherence tomography; ONH: optic nerve head; pAUROC: partial area under the receiver operating characteristic curves; PPG: Preperimetric glaucoma; PSD: pattern standard deviation; RGCs: retinal ganglion cells; S: superior hemisphere; SE: spherical equivalence; SN: superonasal; ST: superotemporal; T: temporal; VFI: visual field index
Diagnostic procedures like the Heidelberg Retina Tomograph 3 (HRT3) (Heidelberg Engineering GmBHa, Heidelberg, Germany), spectral domain optic coherence tomography (SD-OCT) (Carl Zeiss Meditec AG, Jena, Ger- many), and stereo photography were developed to objectively evaluate the ONH. The aim of this study was to assess the correlation of the RNFL (SD-OCT), coefficients of the HRT3, and the DDLS in preperimetric glaucoma. In this study, the DDLS was objectively measured by the KOWA nonmyd WX 3D fundus camera (2D/3D Nonmydriatic Retinal Camera; Kowa Company Ltd., Tokyo, Japan).
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Purpose: We compared the thickness of circumpapillary retinal nerve fiver layer (cpRNFL) and macular ganglion cell layer with inner plexiform layer (GCL + IPL) using Cirrus HD-OCT (Ver.6.0: Carl Zeiss). Materials and Methods: This study included 12 eyes of normal controls, 10 eyes of pre- perimetric glaucoma (PPG) with loss of RNFL either in superior or in inferior hemisphere without visual field defects, and 22 eyes of glaucoma eyes with visual field defects restricted to upper he- mifield (UHFD: early 10 eyes, severe 12 eyes). The cpRNFL thickness analyzed from disk center by dividing into 12 sectors. The GCL + IPL thickness analyzed from central fovea by dividing into six sectors. Both compared between normal eye group and other 3 groups using the average value of each sectors. Result: The cpRNFL and the GCL + IPL thickness were obviously thin as compared with normal eyes. Conclusion: Even if it is in the state where abnormalities are not detected using the Humphrey field Analyzer, it is suggested that the early structural change of glaucoma has al- ready arisen.
All subjects underwent complete ophthalmic examination, including a review of medical history, slit-lamp biomicroscopy of anterior and posterior segment, gonioscopy, Goldmann applanation tonometry, ultrasound pachymetry, and papillary and macular imaging using FD-OCT (RTVue software version A4, 5, 0, 59). Visual field examination was obtained for each eye using standard automated perimetry performed with a Humphrey Field Analyzer (HFA) (Carl Zeiss Meditec, Jena, Germany) using the Swedish interactive threshold algorithm (SITA) standard strategy, program 24-2. All patients with glaucoma were given at least two HFA tests. To minimize any learning effects, only the most recent HFA was used for analysis. To be included in the study, the eyes of all participants required good quality (false positives, fixation losses, false negatives of 25% or less with no observable testing artifacts) standard automated perimetry (Humphrey SITA 24-2 standard) for each eye.
The progressive loss of retinal ganglion cells and thinning of the neuroretinal rim and the retinal nerve fiber layer (RNFL) correspond with deterioration of the visual field   . Clinical studies have provided evidence that the structural damage in glaucoma precedes the functional change, a condition that has been termed pre-perimetric glaucoma. The idea of this concept is that the eye has a functional reserve whereby early structural damage does not directly lead to functional damage. This hypothesis is mainly based on the observation that, in early stages of the disease, the structural damage predominates, whereas in the later stages, functional damage predominates. The lack of sensitivity of visual field testing is due to physiological redundancy in retinal ganglion cell re- ceptive fields. It is well known that patients with glaucoma can suffer a 20% to 50% loss of retinal ganglion cells before a defect becomes evident in standard pe- rimetry  . The atrophy of the RNFL , which is an early sign of glauco- matous damage of the retinal ganglion cells and their axons, is often left unde- tected by ophthalmoscopy and photography of the optic disc and the RNFL. In the last decade spectral-domain optical coherence tomography (SD-OCT) has been widely used to detect structural glaucoma changes     . Although the diagnostic accuracy of SD-OCT is satisfactory in moderate and advanced glaucoma, its accuracy in early and preperimetric glaucoma has still not met the clinical needs. Circumpapillary RNFL thickness and macular gan- glion cell complex thickness have been successfully used for diagnostic and fol- low-up purposes. At present, there is no consensus on which is the best structure parameter for early glaucoma diagnosis, and it is still unknown whether one or several of these diagnostic parameters should be used in the clinical diagnosis of early glaucoma .
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Abstract: The early detection of glaucoma is important in order to enable appropriate monitoring and treatment, and to minimize the risk of irreversible visual field loss. Although advances in ocular imaging offer the potential for earlier diagnosis, the best method is likely to involve a combination of information from structural and functional tests. Recent studies have shown it is possible to estimate the number of retinal ganglion cells from optical coherence tomography and standard automated perimetry, and to then pool the results to produce a combined structure– function index (CSFI). The CSFI represents the estimated percentage of retinal ganglion cells lost compared to an age-matched healthy eye. Previous studies have suggested that the CSFI is better able to detect glaucoma than isolated measures of structure and function, and that it performs well even in preperimetric glaucoma. The purpose of this review is to describe new strategies, such as the CSFI, that have the potential to improve the early detection of glaucoma. We also describe how our ability to detect early glaucoma may be further enhanced by incor- porating demographic risk factors, clinical examination findings, and imaging and functional test results into intuitive models that provide estimates of disease probability.
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The most informative OCT parameters in differentiating preperimetric glaucoma included GCC average thickness, inferior quadrant RNFL thickness, inferior GCC thickness and superior GCC thickness. 11,65,66 Kim et al 45 suggested that GCC thickness appeared to be a better diagnostic bio- marker for early glaucoma than did RNFL thickness. Moreover, the OCT-derived macular GCC parameters exhibited high sensitivity in differentiating glaucomatous from normal eyes. In particular, the GLV predicted preperi- metric glaucoma (odds ratio [OR]:1.74) and early glaucoma (OR = 1.22), and the FLV demonstrated greater predictive value in detecting advanced glaucoma (OR = 2.32). 67 In addition, Naghizadeh et al 68 hypothesized that pattern- derived GCC parameters (i.e., GLV and FLV) were better able to detect early structural glaucomatous changes with respect to other GCC parameters in addition to RNFL thickness and optic nerve head analysis.
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The outcome measure was IOP control with or with- out anti-glaucoma medication at six months post operatively. The tonometric outcome of trabeculec- tomy with MMC was assessed based on the follow- ing operational definition: Complete success: if the mean IOP was ≤21 and >5 mmHg without anti- glaucoma medications, qualified success: if the mean IOP was ≤21 and >5 mmHg with anti-glaucoma medication, failure: if mean IOP was >21mmHg with anti-glaucoma medication and hypotony: if IOP was ≤5mmHg. Stages of glaucoma was decided based on vertical cup-to –disc ratio (VCDR). Early if VCDR was ≤0.65, moderate if VCD R was 0.7 to 0.85 and advanced if VCDR was >0.85. Data were coded, entered onto and analyzed using SPSS version 21.0.We used Chi square test and binary logistic re- gression to see association.
risk factors that need to be considered in the management of glaucoma. The biome- chanical characteristics of the cornea, especially central corneal thickness (CCT), play a role in the accuracy of IOP measurement and glaucoma risk. The Ocular Hypertension Treatment Study ignited much discussion regarding the role that CCT has on the risk for glaucoma development or progression. 5 Along with that discussion there has been
All the IOP measurements, laser treatments, and follow-up evaluations were conducted by a single glaucoma specialist. The patients had been diagnosed as having either POAG, pseudoexfoliation glaucoma, pigmentary glaucoma, or ocular hypertension (OHT) (Table 1). They were all receiv- ing maximum tolerated glaucoma medical treatment and had an uncontrolled IOP of $20 mmHg. The primary outcome of this study was the IOP-lowering effect of SLT compared to ALT at 12 months. The secondary outcome was to obtain IOP measurements at 1 week and 1, 3, and 6 months follow- ing each procedure. Surgical success was defined as having reached a decrease of $15% in IOP from baseline by the time of the final follow-up at the first postoperative year.
There was a discrepancy between the proportion of respondents with a positive attitude towards glaucoma screening (61.2%) and the proportion actually undergoing screening (5%). This discrepancy persisted even among those who were aware of glaucoma. While 70.6% of them were willing to undergo glaucoma screening, only 27.1% had gone for routine eye screening. It has been suggested that since the disease is often symptomless, the motivation for routine glaucoma screening will only stem from good knowledge about the disease  , which was found to be very poor in this study.
PXG and PACG are considered infrequent subtypes in SSA. In our clinical series, PXG was the most common type (41.4 %) and PACG accounted for 17.3 % of the cases; this is in agreement with a previous clinic based report of glaucoma subtypes in the same hospital . PXG patients tended to present at older age (64.6 ± 10.8 years) while PACG (53.2 ± 9.9 years) and OHT (51.5 ± 16.1 years) patients were younger. This was statistically significant (p < 0.01). PXG eyes also presented with higher IOP (37.4 ± 9.6 mmHg) than the other groups. These find- ings support the evidence that PXG patients present at older age, with higher baseline IOPs than other types, particularly POAG .
Recurrent episodes of raised IOP because of an intermittent or subacute angle closure. The angle becomes narrow & narrow at intervals due to pupillary block. But the aqueous manages to sweeps into the anterior chamber by breaking the pupillary block spontaneously. So IOP becomes normal at the time of presentation. Repeated attacks may lead to chronic glaucoma hence early iridotomy is needed in these patients even though IOP may be normal at presentation. Signs and symptoms are only mild and hence most patients do not seek medical counsel at early stage.
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Pseudo exfoliation is the most common cause of secondary open angle glaucoma. The Blue Mountains eye study showed that the incidence of glaucoma in eyes with PEXF is 9 times higher (14.2%) than the eyes without PEXF (1.7%).  The eyes with PEXF have a higher risk, which is independent of other risk factors including IOP.  They are associated with a thinner CCT,  which leads to an underestimation of IOP and thereby a delayed diagnosis. Thinner CCT itself serves as another independent risk factor for development of glaucoma.  All these factors coupled together place the individuals with PEXF at a very high risk of advanced glaucomatous damage than primary open angle glaucoma.
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Methods: We investigated MTHFR C677T genotypes and alleles frequencies in primary glaucoma [primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG)] patients and matched healthy controls in a case-control study. Two hundred ten primary glaucoma cases were studied for MTHFR C677T polymorphism and compared with 280 controls taken from the healthy population, employing the polymerase chain reaction-restriction fragment length polymorphism technique (PCR-RFLP). The MTHFR gene was amplified using specific primers. The PCR products (294 bp) was subsequently digested with HinfI (New England Biolabs) at 37 °C for 12 h, separated by electrophoresis on 2 % agarose gels, and visualized with ethidium bromide staining. The restriction digestion yielded 168 and 126 bp fragments for TT, 294, 168 and 126 bp fragments for CT and undigested PCR product 294 bp indicating CC genotype.
PROM = Patient reported outcome measure. CI = Confidence interval. EQ-5D = European quality of life in 5 dimensions. VAS = Visual analogue scale. SF-36 = Short from 36. GQL-15 = Glaucoma quality of life. GAL = Glaucoma activity limitation. MD = Mean deviation change in worse-eye. dB = Decibels.
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The diagnostic criteria for glaucoma include 1)intraocular pressure measurement, 2)optic nerve head evaluation, 3)retinal nerve fiber layer and 4)visual field defect. . Optic nerve head assessment in fundus images is more promising and advanced. The observation of optic nerve head, cup to disc ratio (CDR) and neural rim configuration are important for early detecting glaucoma in clinical practice. Due to increase in IOP, the cup size begins to increase which consequently increases the CDR. As the cup size increases it also affects the Neuroretinal Rim (NRR) . NRR is the region located between the edge of the disc and the physiological cup. In the presence of glaucoma, area ratio covered by NRR in superior and inferior region becomes thin as compared to area covered by NRR in nasal and temporal region. The digital fundus image of a normal eye and glaucoma tic disc and inferior, superior, nasal and temporal (ISNT quadrants) are illustrated in Figure 1.
ber between normal controls and glaucoma subjects. Venular diameter was significantly reduced in PACG, POAG, and NTG eyes compared to normal controls. Arteriolar diameter was not found to be different between the glaucoma groups and normal controls. When divided according to severity, arteriolar diam- eter was significantly lower in PACG eyes with more severe disease. There were no significant differences in the arteriolar diameter between the eyes in POAG and NTG groups. As the RNFL thickness difference between the worse and the better eyes in PACG was twice that of POAG and NTG in our study group, it is possible that the difference in severity in POAG and NTG was not substantial enough to show a significant difference in vessel caliber. There was no difference in any of the parameters when the glaucoma subjects were classified according to the presenting IOP or anatomical structure.
A Wilcoxon signed-rank test was used to compare IOP levels and numbers of glaucoma medications. An analysis of vari- ance test was used for factors influencing the volume of blebs. In order to see the correlation between the volume of blebs and postoperative IOP, the Spearman coefficient was examined. A Kaplan–Meier survival analysis and log-rank tests were used for comparison of the success rates. All of the statistical analyses were performed with JMP Pro 11 software (SAS, Cary, NC, USA). Significance was defined as P-values ,0.05.