Background: Conventional experimental approaches to understand glaucoma etiology and pathogenesis and, consequently, predict its course of progression have not seen much success due to the involvement of numerous molecular, cellular, and other moieties. An overwhelming number of these moieties at different levels combined with numerous environmental factors further complicate the intricacy. Interaction patterns between these factors are important to understand yet difficult to probe with conservative experimental approaches. Methods: We performed a system-level analysis with mathematical modeling by developing and analyzing rate equations with respect to the cellular events in glaucoma pathogenesis. Twenty-two events were enlisted from the literature survey and were analyzed in terms of the sensitivity coefficient of retinal ganglion cells. A separate rate equation was developed for cellular stress also. The results were analyzed with respect to time, and the time course of the events with respect to various cellular moieties was analyzed. Results: Our results suggest that microglia activation is among the earliest events in glaucoma pathogenesis. This modeling method yields a wealth of useful information which may serve as an important guide to better understand glaucoma pathogenesis and design experimental approaches and also identify useful diagnostic/predictive methods and important therapeutic targets. Conclusion: We here report the first mathematical model for glaucoma pathogenesis which provides important insight into the sensitivity coefficient and glia-mediated pathology of glaucoma.

Introduction: Quality of life (QoL) is a broad concept that is affected in a complex way by many factors. Healthcare interventions are targeted now days to improve quality of life of affected individuals. Glaucoma is a major cause of irreversible blindness throughout the world and affects patient's quality of life in several ways. In present study, we aim to evaluate and quantify vision related quality of life in glaucoma patients in a tertiary care hospital setting. Materials and methods: Vision related quality of life was evaluated in glaucoma patients using GQL-15 questionnaire, which compares the subjective performance of various vision related tasks in these patients. Fifty diagnosed cases of glaucoma and fifty healthy volunteers were included in the study. In both these groups, standard tests for visual function were done and both were assigned to complete the questionnaire. GQL-15 questionnaire includes 15 items divided between 4 factors pertaining to visual disability: central and near vision, peripheral vision, dark adaptation and glare, and outdoor mobility. Higher scores indicate greater difficulty in performing vision-related activities and poorer QoL. Results: A total of 100 cases were enrolled out of which 50 were diagnosed glaucoma cases and 50 were controls. Almost three fourth of glaucoma patients, i.e., 72% were diagnosed as chronic open angle glaucoma where 24% were angle closure patients and rest 4% were normal tension glaucoma patients. The mean GQL score of glaucoma cases was 26.00 ± 10.84 and for controls it was 15.02 ± 0.14 (p value < 0.05). All subscale scores also showed a uniform rise in their value as we move from mild to severe cases thereby concluding that all visual parameters worsen with increase in severity pattern of disease. Conclusions: As glaucoma patients have reduced vision related quality of life, so every effort should be made to preserve visual functions in these patients. Many activities that define independence and productivity in society require good vision and hence one of most devastating consequences of advancing visual impairment in glaucoma is progressive loss of independence thereby affecting patients quality of life.

Purpose: To compare two generations of Heidelberg SPECTRALIS optical coherence tomography (OCT) technologies (SPECTRALIS OCT1 and OCT2) with regard to time efficiency and image quality of retinal nerve fiber layer (RNFL) thickness and Bruch's membrane opening (BMO) analysis in individuals with glaucoma. Materials and methods: In this single center, prospective cohort study, 35 consecutive glaucoma patients (70 eyes) were included. RNFL thickness and BMO-MRW analysis was performed in all patients using the Heidelberg SPECTRALIS OCT1 and the Heidelberg SPECTRALIS OCT2 module. Each patient was imaged three times both with the SPECTRALIS-OCT1 and the SPECTRALIS-OCT2 device. All scans were assessed for further analyzability. Acquisition duration, signal-to-noise ratio (SNR), and the displacement between the initially localized and the redetermined BMO center were extracted from the measurement protocols and statistically compared. Results: Mean (cumulative) scan acquisition duration was significantly higher with OCT1 compared with OCT2 (54.80 ± 18.61 seconds vs 20.40 ± 6.61 seconds; p < 0.01). Patient-related comparison showed a lower scan duration with the OCT2 device in all 35 patients. Mean SNR of the OCT1 images was 29.9 dB and 32.3 dB for the OCT2 images. The difference of −2.4 (95% CI: −3.1 to 2) was highly significant (p < 0.001). Mean displacement of the OCT1 images was 42.9 ìm and 40.2 ìm for the OCT2 images (95% CI: −4.710; p = 0.479). Conclusion: With SPECTRALIS OCT2, acquisition time of BMO and RNFL scans is less than half of the acquisition time of SPECTRALIS OCT1. Image quality of OCT2 module is at least equivalent to the image quality of OCT1.

Purpose: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness and radial peripapillary capillary (RPC) vessel density (VD) in the eyes with unilateral primary angle-closure glaucoma (PACG) with the visual field (VF) defect confined to the superior hemifield and compare these parameters with the corresponding perimetrically intact regions of the fellow eye with primary angle-closure (PAC) and normal control eyes, using optical coherence tomography angiography (OCTA). Materials and methods: This prospective, cross-sectional study included 28 eyes with unilateral PACG, with VF defects restricted to the superior hemifield, 28 fellow eyes with PAC, and 30 age-matched normal controls. Peripapillary RNFL thickness and RPC VD were measured in the eight peripapillary sectors, using OCTA, and these parameters were compared among the corresponding sectors of PACG, PAC, and healthy eyes using analysis of variance (ANOVA) with the Bonferroni post hoc analysis. Results: In PACG eyes, there was a significant difference in the RNFL thickness (p < 0.0001) and RPC VD (p = 0.001) between the superior and the inferior hemifield. In PAC and normal eyes, there was no significant difference in the RNFL thickness and RPC VD between the superior and the inferior hemifield. Within the perimetrically intact regions of the PACG eyes, the mean RNFL thickness was significantly reduced in the superonasal (SN) and upper nasal (UN) sectors (p = 0.02), but the VD did not show any significant difference, when compared to the fellow PAC eyes. In PACG eyes, the mean RNFL thickness was significantly reduced in the perimetrically normal SN and UN sectors (p < 0.0001) and the VD was reduced in the UN sector (p = 0.01), when compared to the normal eyes. When comparing the peripapillary sectors of the PAC and healthy eyes, RNFL thickness was reduced in UN (p = 0.02), lower nasal (LN) (p = 0.01), inferonasal (IN) (p = 0.02), and inferotemporal (IT) sectors (p = 0.03) and there was no significant difference in the VD in any of the sectors. Inside disc capillaries were preserved in all the three groups. Conclusion: Sector-wise RNFL thinning seems to precede the vascular changes and functional loss in the PAC and PACG eyes.

Aim: To perform a correlation analysis between long-term intraocular pressure (IOP) variation parameters (mean, peak, and fluctuation) in patients with stable open-angle glaucoma (OAG). Materials and methods: A cross-sectional observational study was carried out, in which patients with stable OAG were consecutively enrolled. All patients had to have glaucomatous optic neuropathy and characteristic visual field (VF) defects. Key inclusion criteria were ≥5 VF tests, ≥3 disc photographs, and ≥3 years of follow-up without any changes in current medical regimen. Stable OAG was defined as nonprogressive VF results and absence of anatomical changes for at least 3 years. Long-term IOP variation parameters were obtained from isolated IOP measurements from each visit (minimum of five IOP measurements). The main outcome measure was the correlation between these IOP variation parameters. Results: Of the 63 patients studied, 37 (59%) were women, and the mean age was 61 ± 12 years. Among all the analyses, IOP mean and peak had the strongest correlation (r = 0.94; 95% CI = 0.92–0.97; p < 0.001). There were also significant correlations between IOP peak and IOP fluctuation (r = 0.84; 95% CI = 0.75–0.90; p < 0.001), and mean IOP and IOP fluctuation (r = 0.62; 95% CI = 0.43–0.75; p < 0.001). Conclusion: Most long-term IOP variation parameters evaluated seem to be highly correlated. Notably, the correlation between mean IOP and IOP peak was the strongest one. We believe this fact should be taken into consideration as their inclusion as individual variables in a multiple regression model could lead to misinterpretation of the data. Clinical significance: Different well-designed studies are conflicting regarding which long-term IOP variation parameter is more clinically relevant. Our findings suggest that collinearity issues could explain in part the discrepant results among these studies evaluating the relationship between long-term IOP variation parameters and glaucoma prognosis.

Aim: To compare intraocular pressure and anterior chamber angle changes between pilocarpine and laser peripheral iridotomy in primary angle closure. Materials and methods: In this clinical trial study, 34 eyes of 29 patients with primary angle-closure were prospectively enrolled between November 2015 and February 2016. Intraocular pressure and anterior segment optical coherence tomography were performed at three separate times: on the initial conditions, 3–5 days of administration of topical pilocarpine 2%, and 1 week after laser iridotomy. Anterior chamber angle parameters were the angle opening distance (AOD) and trabecular–iris space area (TISA). Results: The intraocular pressure reduction following pilocarpine administration was significant compared to laser iridotomy: 3.9 mm Hg (−32.5 to 0.20) vs 1.8 mm Hg (−33.5 to 2.30) (p = 0.002). Meanwhile, the increment of angle parameters following laser iridotomy was significant compared to pilocarpine. The AOD750 increment of both nasal and temporal quadrant following laser iridotomy was significant compared to pilocarpine: 0.13 mm (−0.27 to 0.28) vs 0.05 mm (−0.35 to 0.29) (p = 0.003) and 0.12 mm (−0.10 to 0.34) vs 0.04 mm (−0.27 to 0.19) (p = 0.002), respectively. The TISA750 increment of both nasal and temporal quadrant following laser iridotomy was also significant compared to pilocarpine: 0.05 mm2 (−0.06 to 0.20) vs 0.02 mm2 (−0.12 to 0.13) (p = 0.023) and 0.04 mm2 (−0.04 to 0.17) vs 0.01 mm2 (−0.14 to 0.18) (p = 0.012), respectively. Conclusion: Laser peripheral iridotomy widens the angle greater than topical pilocarpine, but topical pilocarpine lowers the intraocular pressure greater than laser iridotomy. These data suggest that pilocarpine has another mechanism to decrease the intraocular pressure in primary angle-closure, besides widening the angle.

Aim: The aim of this study is to assess the effectiveness of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor (HDI) with a broad spectrum epigenetic activity, in improving filtration bleb survival as an adjunct therapy to glaucoma filtration surgery (GFS) in the rabbit model. Materials and methods: Eighteen New Zealand White rabbits underwent GFS in the left eye and were randomized to receive either a subconjunctival (SC) injection of 0.1 mL SAHA (9.25 μg/mL) or balanced saline solution (BSS) at the end of surgery, or a 3-minute intraoperative topical application of 0.4 mg/mL mitomycin-C (MMC). Bleb survival and histology were compared. Results: Blebs of rabbits receiving injections of SAHA survived an average (mean ± SD) of 23.2 ± 2.7 days. SAHA rabbits showed a nonsignificant improvement over rabbits that received an injection of BSS, which had a mean survival time of 19.7 ± 2.7 days (p = 0.38) according to a one-way analysis of variance (ANOVA). Eyes receiving intraoperative topical MMC survived an average of 32.5 ± 3.3 days, which is significantly longer than both the control group treated with BSS (p = 0.01) and the experimental group treated with the SAHA (p = 0.0495). SAHA was well tolerated and showed no significant avascularity, necrosis, or conjunctival thinning. Conclusion: Although it was well tolerated, a single intraoperative injection of SAHA did not significantly prolong bleb survival in the rabbit model. Clinical significance: Epigenetic adjuncts hold promise for improving GFS outcome; however, future studies must continue to examine different administration protocols and dosages to substantiate their efficacy.

A 79-year-old man underwent phacoemulsification (phaco) with TORIC intraocular lens (IOL) insertion combined with Kahook dual blade (KDB) goniotomy of the right eye several months after a stand-alone phaco in the fellow eye. He had significant against-the-rule astigmatism in both eyes (2.41D @ 10° right, 2.40D @ 160° left) preoperatively. Postoperatively, nearly all corneal astigmatism disappeared in the right eye (0.60D @ 37°), while it remained the same in the left eye (2.00D @ 167°). Ophthalmologists should be aware that KDB may have an unreported effect of altering corneal astigmatism, which should be considered when inserting TORIC IOL.