Long-term effect of YAG laser iridotomy on corneal endothelium in primary angle closure suspects: a 72-month randomised controlled study

The Japan Glaucoma Society guidelines for glaucoma 5th edition

We are pleased to bring you the 5th edition of the Glaucoma Clinical Practice Guidelines. Clinical practice guidelines are based on evidence (scientific grounds). It is a document that presents the treatment that is the most appropriate for the patient. "Glaucoma Clinical Guidelines" was first published in 2003. This was the first guideline for glaucoma treatment in Japan. The principle of glaucoma treatment is to lower intraocular pressure. Means for lowering intraocular pressure includes drugs, lasers, and surgery; Glaucoma is a disease that should be considered as a complex syndrome rather than a single condition. Therefore, the actual medical treatment is not as simple as one word. This time we set the Clinical Questionnaire with a focus on glaucoma treatment. We hope that you will take advantage of the 5th edition.

Iridotomy to slow progression of visual field loss in angle-closure glaucoma

BACKGROUND

Primary angle-closure glaucoma is a type of glaucoma associated with a physically obstructed anterior chamber angle. For example, contact between the iris and lens at the pupillary margin creates a pupillary block that increases resistance to aqueous outflow. Obstruction of the anterior chamber angle blocks drainage of fluids (aqueous humor) within the eye and may raise intraocular pressure (IOP). Elevated IOP is associated with glaucomatous optic nerve damage and visual field loss. Laser peripheral iridotomy ('iridotomy') is a procedure to eliminate pupillary block by allowing aqueous humor to pass directly from the posterior to anterior chamber, which is achieved by creating a hole in the iris using laser. Iridotomy is used to treat patients with primary angle-closure glaucoma, patients with primary angle-closure (narrow angles and no signs of glaucomatous optic neuropathy), and patients who are primary angle-closure suspects (patients with reversible obstruction). However, the effectiveness of iridotomy on slowing progression of visual field loss is uncertain.

OBJECTIVES

To assess the effects of iridotomy compared with no iridotomy for primary angle-closure glaucoma, primary angle-closure, and primary angle-closure suspect.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2021, Issue 10), which contains the Cochrane Eyes and Vision Trials Register; MEDLINE Ovid; Embase Ovid; PubMed; LILACS; ClinicalTrials.gov; and the WHO ICTRP. The date of the most recent search was 10 October 2021.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials that compared iridotomy with no iridotomy in primary angle-closure suspects, people with primary angle-closure, or people with primary angle-closure glaucoma in one or both eyes were eligible.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and assessed the certainty of the body of evidence for prespecified outcomes using the GRADE approach.

MAIN RESULTS

We identified four studies (3086 eyes of 1543 participants) that compared iridotomy with no iridotomy in participants (range of mean age 59.6 to 62.9 years) who were primary angle-closure suspects from China, Singapore, or the UK. Study investigators randomized one eye of each participant to iridotomy and the other to no iridotomy. Two studies provided long-term (five or more years) results. We judged the certainty of the evidence as moderate to low across the prespecified outcomes, downgrading for high risk of bias (e.g. performance and detection biases) and imprecision of results. Meta-analyses of data from two studies suggest that iridotomy probably results in little to no difference in IOP compared with no iridotomy at one year (mean difference (MD) 0.04 mm Hg, 95% confidence interval (CI) -0.17 to 0.24; I2 = 65%; 2598 eyes of 1299 participants; moderate certainty evidence) and five years (MD 0.12 mm Hg, 95% CI -0.11 to 0.35; I2 = 0%; 2016 eyes of 1008 participants), and in best-corrected visual acuity measured as logMAR at one year (MD 0.00, 95% CI -0.01 to 0.01; I2 = 69%; 2596 eyes of 1298 participants; moderate certainty evidence) and five years (MD 0.01, 95% CI -0.01 to 0.03; I2 = 0%; 2002 eyes of 1001 participants). In terms of gonioscopic findings, eyes treated with iridotomy likely had wider angles in Shaffer grading scale (MD 4.93 units, 95% CI 4.73 to 5.12; I2 = 59%; 2598 eyes of 1299 participants at one year; MD 5.07, 95% CI 4.78 to 5.36; I2 = 97%; 2016 eyes of 1008 participants at five years; moderate certainty evidence) and experienced fewer peripheral anterior synechiae (PAS) than eyes that received no iridotomy at five years (risk ratio (RR) 0.41, 95% CI 0.24 to 0.67; I2 = 28%; 2 studies, 2738 eyes of 1369 participants), but the evidence was less conclusive at one year (RR 0.62, 95% CI 0.25 to 1.54; I2 = 57%; 3 studies, 2896 eyes of 1448 participants; low certainty evidence). No studies reported data on the proportion of participants with progressive visual field loss during follow-up (the primary outcome of this review), mean number of medications to control IOP, or quality of life outcomes. Low certainty evidence suggests that iridotomy may result in little to no difference in the incidence of acute angle-closure (RR 0.29, 95% CI 0.07 to 1.20; I2 = 0%; 3 studies, 3006 eyes of 1503 participants). Other ocular adverse events (e.g. eye pain, dry eye, redness of eyes, and ocular discomfort), although rare, were more common in eyes treated with iridotomy than in eyes in the control group.  AUTHORS' CONCLUSIONS: We did not find sufficient evidence to draw any meaningful conclusions on the use of iridotomy for the purpose of slowing progression of visual field loss. No study reported on progressive visual field loss, the primary outcome of this review. Although there is moderate certainty evidence that iridotomy results in improved gonioscopic findings, in is unclear if these findings translate to clinically meaningful benefits.

Clinical implication of recent randomized control trial in primary angle-closure disease management

Blindness due to primary angle-closure glaucoma (PACG) can be reduced significantly if the ongoing angle-closure process is arrested at an early stage. Various treatments such as laser peripheral iridotomy (LPI), iridoplasty, and clear lens extraction (CLE) have been advocated as first-line therapy for primary angle-closure (PAC), PACG, and high-risk cases of primary angle-closure suspect (PACS). EAGLE study, propagated the effectiveness of CLE over LPI for the management of primary angle closure and have sparked controversy regarding the role of LPI as a first line procedure. Randomized controlled trials (RCT), systematic reviews, and meta-analyses of RCTs done on the same question provide us with a solid base for creating guidelines/modules for our day-to-day clinical practice. A systematic review was conducted, searching several databases, including PubMed, Cochrane Library, EMBASE, and ClinicalTrials.gov, for the last 16 years (January 2005–December 2021) for RCTs with data published related to primary angle-closure disease (PACD). The search strategy included the following terms: “Primary Angle Closure disease,” “Primary Angle Closure Glaucoma,” “Primary Angle Closure,” “Primary Angle Closure Suspect,” “clear lens extraction,” “laser iridotomy,” “laser peripheral iridotomy,” “argon laser peripheral iridoplasty,” “selective laser trabeculoplasty,” “trabeculectomy,” “randomized control trial,” and “meta-analysis of randomized control trial.” In this review, we will discuss recently published RCTs (within the last 16 years) for the management of PACD and their clinical implications in day-to-day practice.

Self-identified Black Race as a Risk Factor for Intraocular Pressure Elevation and Iritis Following Prophylactic Laser Peripheral Iridotomy

PRCIS

In primary angle closure suspects (PACS), self-identified Black race was a risk factor for intraocular pressure (IOP) elevation and iritis following laser peripheral iridotomy (LPI). Laser type was not associated with either immediate post-LPI IOP elevation or iritis in multivariate analysis.

PURPOSE

The aim was to determine the impact of laser type and patient characteristics on the incidence of IOP elevation and iritis after LPI in PACS.

MATERIALS AND METHODS

The electronic medical records of 1485 PACS (2407 eyes) who underwent either neodymium-doped yttrium-aluminum-garnet or sequential argon and neodymium-doped yttrium-aluminum-garnet LPI at the University of Pennsylvania between 2010 and 2018 were retrospectively reviewed. Average IOP within 30 days before LPI (baseline IOP), post-LPI IOP within 1 hour, laser type, laser energy, and the incidence of new iritis within 30 days following the procedure were collected. Multivariate logistic regression accounting for intereye correlation was used to assess factors associated with incidence of post-LPI IOP elevation and iritis, adjusted by age, sex, surgeon, and histories of autoimmune disease, diabetes, and hypertension.

RESULTS

The incidence of post-LPI IOP elevation and iritis were 9.3% (95% confidence interval: 8.1%-10.5%) and 2.6% (95% CI: 1.9%-3.2%), respectively. In multivariate analysis, self-identified Black race was a risk factor for both IOP elevation [odds ratio (OR): 2.08 compared with White; P=0.002] and iritis (OR: 5.07; P<0.001). Higher baseline IOP was associated with increased risk for post-LPI IOP elevation (OR: 1.19; P<0.001). Laser type and energy were not associated with either post-LPI IOP elevation or iritis (P>0.11 for all).

CONCLUSIONS

The incidence of immediate IOP elevation and iritis following prophylactic LPI was higher in Black patients independent of laser type and energy. Heightened vigilance and increased medication management before and after the procedure are suggested to help mitigate these risks.

Long-Term Outcome of Corneal and Anterior Chamber Angle Parameters after Combined Laser Iridotomy and Iridoplasty Using Dual Scheimpflug Analyzer: 1 Year Results

Background: To investigate the outcomes of corneal and anterior chamber angle (ACA) parameters after laser iridotomy (LI) combined with peripheral iridoplasty (PI) using dual Scheimpflug analyzer in the long term. Methods: Fifty-eight eyes (58 subjects) with shallow AC were included in this prospective cohort study. Images of the Dual Scheimpflug analyzer were obtained before, 1 week, and 1 year after LI and PI. Pachymetry from three zones (central, middle, and peripheral), corneal aberration, and spherical equivalent (SE) were acquired. AC depth (ACD), AC volume (ACV), ACA from four quadrants, and intraocular pressure (IOP) were also obtained. For comparison of the results, the linear mixed-effects model was employed. Results: ACD significantly increased from 2.09 ± 0.25 mm to 2.10 ± 0.23 mm at 1 year after laser (all p < 0.05). ACV and ACA increased significantly after laser at 1 year (all p < 0.05). IOP significantly decreased from 15.97 ± 4.20 mmHg to 13.73 ± 2.63 mmHg at 1 year (all p < 0.0001). No significant changes were found in the coma, trefoil, total corneal aberration, pachymetry from three zones, corneal volume, central corneal thickness, and SE after LI and PI until 1 year (all p > 0.05). Conclusions: LI plus PI ameliorated parameters of ACA efficiently and significantly reduced IOP in eyes with shallow AC until 1 year of long-term follow-up. However, parameters of the cornea and SE were not influenced by LI with PI until after 1 year.

Progression rate to primary angle closure following laser peripheral iridotomy in primary angle-closure suspects: a randomised study

AIM

To report the progression rate (PR) to primary angle closure (PAC) following laser peripheral iridotomy (LPI) in PAC suspects (PACS).

METHODS

Prospective, randomized controlled interventional clinical trial conducted at the Handan Eye Hospital, China. Totally 134 bilateral PACS, defined as non-visibility of the posterior trabecular meshwork for ≥180 degrees on gonioscopy were randomly assigned to undergo LPI in one eye. Gonioscopy and Goldmann applanation tonometry were performed prior to, on day 7 and 12mo post LPI.

RESULTS

Eighty of 134 patients (59.7%) could be followed up at one year. The mean intraocular pressure (IOP) in treated eyes was 15.9±2.6 mm Hg at baseline, 15.4±3.0 mm Hg on day 7; 16.5±2.9 mm Hg at one month, and 15.5±2.9 mm Hg at 12mo; the IOP in untreated eyes was similar (P=0.834). One or more quadrants of the angle opened in 93.7% of the LPI treated eyes, but 67.0% (53/79) remained closed in two or more quadrants. The PR to PAC in untreated eyes was 3.75% and one developed acute angle-closure glaucoma (AACG); the PR to PAC in treated eyes was 2.5% and none had developed peripheral anterior synechia (PAS) or AACG.

CONCLUSION

LPI can open some of the occludable angle in the majority of eyes with PACS, but 67% continue to have non-visibility of the trabecular meshwork for over 180 degrees.

Association Between Anterior Chamber Angle and Corneal Endothelial Cell Density in Chronic Angle Closure

Purpose

To study the association between corneal endothelial cell density (ECD) and degree of anterior chamber angle (ACA) opening in eyes with chronic angle closure glaucoma.

Methods

The study was conducted at JEC Eye Hospitals in Indonesia. Treatment-naïve patients aged ≥40 years with IOP >21 mmHg and peripheral anterior chamber depth (ACD) grade 2 or less by Van Herick's technique were recruited. Trabecular iris angle (TIA; degree) was measured using anterior segment optical coherence tomography (AS-OCT) and classified as: grade 1 ≤10°, grade 2 11-20°, and grade 3 >20°. Noncontact specular microscopy was performed, and the following corneal parameters were obtained:ECD (cells/mm²), coefficient of variation (CV; μm²/cell), percentage of hexagonal cells, and central corneal thickness (CCT; μm).

Results

A total of 52 eyes from 52 subjects were recruited (16 grade 1 TIA, 24 grade 2 TIA, and 12 grade 3 TIA). Presenting IOP was not significantly different between groups. The median central corneal ECD was 2684.5 (1433-2934), 2587.0 (1902-3103), and 2441.0 (1659-3005) cells/mm² in grade 1, 2, and 3 TIA, respectively, with no significant differences across the groups (P = 0.67). The CV was lowest in grade 3 TIA (36.4 ± 7.2 μm2/cell), and highest in grade 1 TIA (38.3 ± 9.6 μm2/cell), but the differences were not significant (P = 0.74). Likewise, the percentage of hexagonality and CCT was not significantly different. TIA was not correlated with IOP but was modestly correlated with age.

Conclusion

The corneal ECD and morphological characteristics such as CV and hexagonality were not significantly different across various TIA grading in chronic angle closure. This may reflect the lack of chronic and gradual IOP insult on corneal endothelial parameters as TIA did not show direct effect towards IOP.