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Purpose: To evaluate structural alterations and healing responses in the trabecular meshwork region with optical coherence tomography (AS-OCT) following after gonioscopy assisted transluminal trabeculotomy (GATT) and microincisional trabeculectomy (MIT). Methods: 73 eyes of 67 patients (M:F = 45:22) with ≥6 months of follow-up after MIT (n = 41) or GATT (n = 32) with or without combined cataract surgery were included for this prospective study. The angle as seen on AS-OCT at 1, 3, 6 months after surgery were evaluated for structural alterations like peripheral anterior synechiae (PAS), hyphema, and hyperreflective scarring responses. The scarring was graded according to the linear extent measured from the centre of the trabecular meshwork (TM) gutter to the sclera/cornea as mild (<250μ), moderate (250–500μ), and severe(˃500μ), while the pattern of scarring was graded as open saucer/gutter, closed gutter, and trench pattern. The association of the need for medication or surgical outcome and clinical variables and AS-OCT parameters including the pattern and severity of scarring were analysed using multivariate regression. Results: All eyes achieved significant reduction of IOP and number of medications with a final IOP of 15±3.2mm Hg at a mean follow-up of 8±32. months. While mild scarring was seen more common in MIT, severe scarring was seen in >65% of GATT eyes compared to 31% of MIT eye, p<0.001. An open saucer was equally seen in MIT and GATT while the trench pattern was more commonly seen in GATT eyes (>50%). Severe scarring in a trench pattern seemed to predict the need for medications for IOP control, though they independently did not seem to influence the final IOP or surgical outcome. Conclusion: A severe form of scarring in a trench pattern on AS-OCT predicted the need for glaucoma medications after MIGS surgery. Regular monitoring of the scarring responses by AS-OCT and clinical examination are necessary to identify those at need for medications after MIGS. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the short-term clinical outcomes of microincisional trabeculectomy (MIT), a new technique of ab-interno trabeculectomy. Methods: Consecutive patients with open-angle glaucoma identified from the hospital database that underwent MIT with or without cataract surgery between September 2021 to June 2022 at a tertiary eye centre in East India, were screened. Those with a follow-up of < 6 months or with incomplete data were excluded. MIT was done ab-interno using microscissors and microforceps in 2–4 clock hours of the nasal angle via a temporal incision. The intraocular pressure (IOP) reduction at 6 months, and reduction in the number of medications after surgery were analysed. Surgical success (IOP>6 and <22 mm Hg), complications, angle features on anterior segment optical coherence tomography (ASOCT), and the need for additional surgeries were analysed. Results: We included thirty-two eyes of 32 patients with open-angle glaucoma (including n = 9 eyes that underwent concurrent cataract surgery) with a preoperative mean IOP of 22 ±11.1 mm Hg and visual field index of 47±37.9%. All eyes achieved >30% IOP reduction, with a final IOP of 14±6.9 mm Hg at 6 months. Surgical success in 31 of 32 eyes with complete success seen in 28 eyes with none of the eyes requiring >1 medication for IOP control. Hyphema was seen in 4 eyes, while transient IOP spikes at 1 day-1 month were seen in 5 eyes, none of which required any additional interventions. One eye with persistent raised IOP at 1 month required incisional trabeculectomy for uncontrolled IOP with 2 medications. Conclusion: MIT, a new technique of ab-interno trabeculectomy, is effective in terms of IOP control and reduction in the number of medications while having fewer complications. Long-term studies comparing the efficacy of MIT with incisional trabeculectomy, or other procedures are warranted in the future. [ABSTRACT FROM AUTHOR]

Purpose: To report the early postoperative causes of intraocular pressure (IOP) spikes after complete circumferential gonioscopy-assisted transluminal trabeculotomy (GATT) using anterior segment optical coherence tomography (ASOCT). Methods: This was retrospective interventional case series of patients who underwent circumferential GATT by a single surgeon (APR) from 2021 to 2022 at a tertiary eye care in East India and who developed IOP spikes at 1 day-2 weeks (immediate) or early (> 2 weeks– 2 months) after GATT. The intraocular pressure (IOP), glaucoma medications, and angle evaluation by ASOCT at 1 week, and 1 month were compared between the two groups. Results: Thirty-two eyes of 32 consecutive patients, aged 40± 20.1 years (20 exfoliation glaucoma, 9 juvenile open-angle, and 3 developmental glaucoma), that developed IOP spikes between immediate (n=20) or early (n=12) IOP spikes after GATT, were included. Immediate postoperative spikes were seen in 20 eyes due to retained viscoelastic (n=8), hyphema (n=8) in uncontrolled hypertension, and peripheral anterior synechiae (PAS) (n=6) of which only one eye required medication at 2 months. Causes of immediate IOP spikes on ASOCT included an inverted/reattached trabecular shelf, iris strands in eyes with abnormal iris in developmental glaucoma, and PAS in 1– 2 quadrants. Causes of early IOP spikes included PAS > 3 quadrants (n=8), and hyperreflective fibrotic tissue over TM (n=4) with 50% requiring medications at 2 months. The ASOCT features predicting the need for medications were PAS > 3 quadrants (OR=8.4[2.2– 14.3], p=0.03) and fibrotic TM closure (OR=5.4, [3.6– 10.2], p=0.003). One eye with macrohyphema 3 days after surgery owing to uncontrolled hypertension (owing to the stoppage of medicines), required additional incisional trabeculectomy within 1 month of surgery. Conclusion: Immediate IOP spikes are mostly self-resolving as opposed to early IOP spikes > 2 weeks that require medications after GATT. Gonioscopic PAS > 3 quadrants, and fibrotic TM closure were the main identifiable ASOCT causes predicting the need for medications after GATT. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate differences in the iris and angle parameters in psuedoexfoliation syndrome (PXF) and pseudoexfoliation glaucoma (PXG) using anterior segment optical coherence tomography (ASOCT).Methods: Patients with PXF or PXG were compared using ASOCT with primary open-angle glaucoma POAG eyes as controls in this noninterventional comparative study conducted at a tertiary eye care center in East India. All angle parameters, TM length, and iris thickness were analyzed from the enhanced depth imaging (EDI) single scans obtained. Quadrant scans were used for the calculation of iris volume using a custom-built in-house software. In particular, the software performs multiple operations including edge detection, connected components, and thresholding to localize and segment the iris. Differences in the iris volume/thickness and TM length in PXF and PXG with POAG were analyzed.Results: A total of 225 eyes were included, which included 75 PXG and 98 PXF cases and 52 POAG with a mean age of 67 ± 9.7 years at presentation. The algorithm repeatability and reproducibility was also established with correlation coefficients more than 99% which was substantiated with Bland-Altman plots. The iris volume (calculated in 197 images of 225 eyes) did not differ significantly in PXF and PXG eyes, although both had significantly greater volume compared to POAG eyes. The iris volume or other angle parameters including TM length did not correlate with clinical variables such as IOP, age, or visual field indices.Conclusion: Iris parameters or TM length do not explain pathogenesis of glaucoma in pseudoexfoliation. [ABSTRACT FROM AUTHOR]

Purpose: To characterize anatomical dimensions of a disc notch using novel methods using spectral domain optical coherence tomography (SD-OCT).Participants: All age- and severity-matched glaucoma patients with disc notch (defined as complete loss of neural rim with no residual rim between disc and cup) seen from 2014 to 2015 who underwent enhanced depth imaging with SD-OCT (Cirrus HD-OCT version 6.5, Carl Zeiss, USA) were included for this retrospective observational study.Methods: Using known dimensions of the 200 * 200 optic disc cube (6 * 6 mm), the notch width was calculated from the margins of the notch on either side using ImageJ software. The height was calculated from the lowest margin of the cup to the lowest point of the defect on the optic disc. These were compared with the quadrant retinal nerve fiber layer (qRNFT) and sectoral retinal nerve fiber layer (sRNFLT) thickness in notch and the sector 2 clock hours adjacent to the notch region (SaRNFLT).Results: The height and width of the notch in 31 eyes of 27 patients were 2.6 ± 0.48 mm and 2.23 ± 0.31 mm. The RNFL thickness in the same sector as that of the notch was 41 ± 21.06 µm while the adjacent two sectors measured 62 ± 26.5 and 64 ± 26.5 µm on either sides of the sector of the notch. The difference between the sRNFLT and saRNFLT ranged from -9 to 67 and -13 to 50 µm, respectively. This difference was significantly associated with height of the notch (R2 = 20.8, p = 0.01).Conclusion: Automated analysis of a notch and RNFL thickness in that sector can help in precise glaucoma monitoring in the region of interest. [ABSTRACT FROM AUTHOR]

BACKGROUND: The aim of this study was to evaluate responses on multifocal electroretinogram (mfERG) with ganglion cell-inner plexiform layer (GCIPL) thickness on cirrus spectral-domain optical coherence tomography (SD-OCT) in glaucoma. METHODS: All diagnosed glaucoma patients attending glaucoma services at our institute from November 2012 to April 2013 were screened for this observational hospital-based study. Controls included patients attending our outpatient services for general eye checkup. Structural parameters on SD-OCT including GCIPL and retinal nerve fiber layer (RNFL) thickness were compared with functional parameters on mfERG in early (mean deviation <-6 dB), moderate (-6 to - 12 dB), and controls. RESULTS: A total of 54 cases and 33 controls fulfilling inclusion criteria were recruited for the study. The average and minimum GCIPL thickness did not vary significantly between early and control eyes while moderate glaucoma eyes had marginally lower GCIPL thickness than early glaucoma eyes. The GCIPL minimum thickness on univariate regression was found to be influenced by N2 amplitudes (β = -0.5, P = 0.012) and global N2P1amplitudes (β =0.6, P = 0.01) in moderate glaucoma. In early glaucoma, these were influenced only by RNFL parameters with no association with functional mfERG responses. Multivariate logistic regression identified global N2P1 amplitude to be significantly influencing GCIPL average and minimum thickness (P = 0.01 and 0.02, R2 = 47.8% and 52.3%, respectively) in moderate glaucoma. Maximum area under the curve was found for GCIPL minimum (95% confidence interval [CI] 0.53–0.81) and N2P1 amplitude (95% CI 0.55–0.80). CONCLUSIONS: The second order responses N2P1 and N2 amplitude on mfERG predict function that correlated with structural GCIPL thickness in moderate glaucoma. Early glaucoma may be best predicted by RNFL thickness rather than on mfERG responses. [ABSTRACT FROM AUTHOR]

Purpose To evaluate first and second order responses on multifocal electroretinogram (mfERG) and with retinal nerve fibre layer thickness (RNFL) on Cirrus spectral domain optical coherence tomography (SD-OCT) in glaucoma. Methods Patients (old and new) diagnosed with primary open angle glaucoma, primary angle closure glaucoma or normal tension glaucoma attending glaucoma services from November 2012 to January 2013 were screened. Ninety-seven eyes fulfilling inclusion criteria were evaluated by Humphrey visual field, Cirrus SD-OCT imaging and mfERG (Veris Science 5.1.10X; EDI, Redwood City, California, USA) for this observational cross-sectional study. The global and averaged quadrant-wise peak-to-trough amplitudes and peak implicit times of the first trough (N1), the first peak (P1) and the second trough (N2) of the mfERG were compared with average RNFL-full circle (FC) or quadrant RNFL thickness in early (mean deviation (MD) >-6 dB), moderate (MD -6 to -12 dB) and advanced glaucoma (MD <-12 dB). Results The RNFL-FC correlated with P1N2 amplitude on univariate analysis (r=0.7, p=0.004) and N2 amplitude (r=-0.4, p<0.001). Comparing relationships in different stages of glaucoma, P1N2 amplitude correlated significantly with RNFL-FC and superotemporal quadrant, RNFL-superior temporal (ST), in early and moderate glaucoma only. In contrast, the implicit time of P1N2 correlated significantly with RNFL-FC and RNFL-ST only in severe glaucoma while in earlier stages, this relationship did not hold true. On multivariate analysis, P1N2 amplitude correlated with age (β=-0.2, p<0.001), RNFL-FC (β=0.05, p=0.05), RNFL-ST (β=0.06, p=0.01) and cup-disc ratio (β=-3.2, p=0.006). Conclusions Of all responses on mfERG, P1N2 amplitude correlates well with RNFL-FC and RNFL-ST on SD-OCT and can be used for monitoring early and moderate glaucoma. Diffuse structural changes may best be reflected by changes in P1N2 implicit time owing to ceiling effect of the amplitude in all regions in severe glaucoma. [ABSTRACT FROM AUTHOR]

Purpose: To compare the visual field index (VFI) in primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) eyes, and to study the correlation with disc variables on optical coherence tomography (OCT) in all stages of severity. Materials and Methods: Thirty POAG and PACG underwent Humphrey visual field 24-2 along with detailed examination. They also underwent stratus OCT imaging of the optic nerve and retinal nerve fiber layer (RNFL). The correlation of VFI with RNFL thickness was compared in POAG and PACG. Results: The VFI significantly differed between POAG and PACG, with POAG eyes apparently having a better VFI at all severities of glaucoma. There were statistically significant differences in the superior max (Smax) and inferior max (Imax) in early and moderate POAG and PACG eyes. In early and moderate glaucoma, multivariate regression showed that maximum correlation of the VFI was seen with the mean deviation (b = 1.7, P < 0.001), average and superior RNFL thickness (b = 2.1, P < 0.001 and b = 1.8, P = 0.03, respectively), and age (b = 0.7, P = 0.04); while no correlation was seen with intraocular pressure (IOP), axial length, sex, or other clinical variables. VFI did not correlate well with RNFL thickness or other disc variables on OCT in severe glaucoma. Conclusion: VFI may not serve as a useful indicator of visual function in severe glaucoma. More useful indicators are required to monitor glaucoma patients with severe damage. [ABSTRACT FROM AUTHOR]

Objectives: To establish a normative database for retinal nerve fiber layer (RNFL) thickness in children<18 years by spectral-domain optical coherence tomography (SD-OCT). Methods: Children <18 years, who were consecutively enrolled from July-August 2011 in this cross-sectional hospital study, underwent Cirrus SD-OCT. Recorded demographics and clinical characteristics included age, sex, axial length, spherical equivalent, intraocular pressure (by Perkins tonometry) and cup disc ratio. The RNFL thickness full circle (RNFL-FC), superior, (RNFL-S), inferior (RNFL-I), temporal (RNFL-T), and nasal (RNFL-N) and the influence of clinical and demographic factors on the RNFL thickness were assessed using linear regression analysis. Results: 148 eyes of 74 children were analyzed (females: males = 37: 37) with a mean age of 10 ± 3.4years (range 4-17 years) and a mean spherical equivalent of −0.6 ± 1.2 dioptres. The mean RNFL-FC was 94 ± 10.9 and 93 ± 10.6 µm in the right and left eyes, respectively, with maximum thickness found in the superior quadrant. The RNFL-FC and RNFL-S decreased by 1.9 µm for every 1 dioptre increase in myopic shift, p < 0.001, and by 1.9 µm for every mm increase in axial length, p < 0.001. There was no effect of age on RNFL thickness in females or males. Conclusions: The RNFL thickness in children was influenced most by axial length and refractive error while it was independent of age. The normative data from this study could serve as reference for further studies on pediatric glaucoma using newer imaging devices. [ABSTRACT FROM AUTHOR]

Purpose: To compare clinical findings and peripapillary retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) in affected and fellow eyes of patients with unilateral pseudoexfoliation (PXF) syndrome with that of bilateral cases. Methods: This cross-sectional study enrolled 91 subjects with PXF including 32 unilateral and 59 bilateral cases. Subjects with elevated intraocular pressure or findings suggestive of glaucoma were excluded. RNFL thickness and optic nerve head profile were studied in all eyes using the RNFL and optic nerve head analysis OCT protocol. Clinical and OCT features were compared in affected and unaffected eyes of unilateral PXF subjects to bilateral cases. Results: Bilateral cases with PXF were older (P<0.01) and had thinner RNFL (P=0.04) than unilateral cases. From a total of 32 unilateral PXF cases, 7 subjects demonstrated RNFL thinning in the clinically normal fellow eye; all of these eyes had evidence of pupillary ruff atrophy on slit lamp examination in the absence of evident exfoliation material in the eye. Similar ruff atrophy with RNFL thinning was seen in 38 of 59 bilateral and in 16 of 32 unilateral cases. Pupillary ruff atrophy predicted RNFL thinning with sensitivity of 88.9% (95% CI, 73-96.7%) and 79.2% (95% CI, 74-84.5%) in bilateral and unilateral cases respectively, with low specificity of 45.8% (95% CI, 33.9-51.7%) and 45.5% (95% CI, 22.9-68.8%) in the same order. Conclusion: Patients with bilateral PXF have significantly thinner RNFL as compared to unilateral cases. Iris sphincter abnormality, clinically detected as pupillary ruff atrophy, may reflect early glaucomatous damage; however the specificity of this sign for predicting RNFL thinning is low. [ABSTRACT FROM AUTHOR]