Non-pupillary block angle-closure mechanisms: a comprehensive analysis of their prevalence and treatment outcomes

Abstract

Approved by the following Research Ethics Committee: Sociedade Brasileira e Japonesa de Beneficência/Hospital Santa Cruz, São Paulo, sob o número (178.759). AbsTRACTPurpose: To assess the prevalence and treatment outcomes of angle-closure mechanisms other than pupillary block in a population of Brazilian patients. Methods: A retrospective chart review was conducted to evaluate patients who had undergone laser peripheral iridotomy (LPI) due to occludable angles at a single institution between July 2009 and April 2012. An occludable angle was defined as an eye in which the posterior trabecular meshwork was not visible for ≥180° on dark-room gonioscopy. Key exclusion criteria were any form of secondary glaucoma and the presence of >90° of peripheral anterior synechiae. Collected data were age, race, gender, angle-closure mechanism (based on indentation goniocopy and ultrasound biomicroscopy), intraocular pressure (IOP), number of antiglaucoma medications and subsequent management during follow-up. If both eyes were eligible, the right eye was arbitrarily selected for analysis. Results: A total of 196 eyes of 196 consecutive patients (mean age 58.3 ± 11.6 years) who underwent LPI were included. In most of the patients [86% (169 patients; 133 women and 36 men]), LPI sucessfully opened the angle. Mean IOP was reduced from 18.3 ± 6.4 mmHg to 15.4 ± 4.5 mmHg after LPI (p<0.01). Among the 27 patients with persistent occludable angles, the most common underlying mechanisms were plateau iris (56%) and lens-induced component (34%). Most of these patients (85%) were treated with argon laser peripheral iridoplasty (ALPI); approximately 90% showed non-occludable angles following the laser procedure (mean IOP reduction of 18.9%), with no significant differences between patients with plateau iris and lens-induced components (p=0.34; mean follow-up of 11.4 ± 3.6 months). Conclusions: Our findings suggest that, in this population of Brazilian patients, several eyes with angle closure were not completely treated with LPI. In the present large case series involving middle-age patients, plateau iris was the leading cause of persistent angle closure and was effectively treated with ALPI. A detailed eye examination with indentation gonioscopy should always be performed after LPI to rule out persistent angle closure due to non-pupillary block mechanisms.

Hidden mechanisms beyond the pupillary block in acute angle closure: ultrasound biomicroscopic study

“…Reported incidences of PL in AAC eyes were from 2.5% to 6.3% . PL accounts for a large proportion of non‐pupillary block component of angle closure in subjects of non‐Asian ethnicity . Our findings suggest that PL rarely elicits AAC by itself in this Asian population.…”

Hidden mechanisms beyond the pupillary block in acute angle closure: ultrasound biomicroscopic study

“…Reported incidences of PL in AAC eyes were from 2.5% to 6.3% . PL accounts for a large proportion of non‐pupillary block component of angle closure in subjects of non‐Asian ethnicity . Our findings suggest that PL rarely elicits AAC by itself in this Asian population.…”

Iridoplasty for plateau iris syndrome: a systematic review

“…After ALPI, IOP decreased from −6.7 mm Hg (−30%) after 1 month15 to −2.8 mm Hg (−19%) (p=0.01),12 −3.4 mm Hg (−19%) (p<0.01),11 −3.6 mm Hg (−20%) (p<0.01),13 −4.4 (−21%) (p=0.012)4 and −7.9 mm Hg (−32%) (p<0.001)16 after 1 year. After a mean follow-up of 6 years, Ritch et al 17 did not find any significant IOP change as compared with baseline (+0.2 mm Hg), similar to Peterson et al ,4 who found a −1.6 mm Hg (p=0.38) non-significant IOP variation.…”

“…Singh et al 12 had the lowest success rate with 46% of patients with angle widening. Junqueira et al 11 found a posterior trabecular meshwork visible on 180° without indentation on gonioscopic examination for 90% of eyes after the laser procedure. Ramakrishnan et al 16 were the only authors to focus on PAS, reducing the median number of clock hours with PAS from 3.75 (2.00–6.50) to 2.50 (0.75–5.00) (p<0.001).…”

“…In studies with at least 1 year of follow-up, weighted IOP decreased from 19.6 mm Hg at baseline to 15.6 mm Hg at the last visit after ALPI, providing a −4.0 mm Hg or −20% IOP variation 4 11–13 16. In the studies with a 6-year follow-up, weighted mean IOP varied from 18.7 mm Hg to 18.5 mm Hg at the last visit after ALPI, providing a −0.2 mm Hg or 1% variation4 17 (figure 2).…”

“…To date, there have been no randomised controlled trials evaluating the use of iridoplasty in chronic angle-closure caused by PIS. We included seven retrospective case series4 9–15 and one prospective observational case–control study16 published between 2004 and 2017. The study characteristics are described in table 1.…”

Hidden mechanisms beyond the pupillary block in acute angle closure: ultrasound biomicroscopic study

“…Reported incidences of PL in AAC eyes were from 2.5% to 6.3% . PL accounts for a large proportion of non‐pupillary block component of angle closure in subjects of non‐Asian ethnicity . Our findings suggest that PL rarely elicits AAC by itself in this Asian population.…”

Iridoplasty for plateau iris syndrome: a systematic review

“…After ALPI, IOP decreased from −6.7 mm Hg (−30%) after 1 month15 to −2.8 mm Hg (−19%) (p=0.01),12 −3.4 mm Hg (−19%) (p<0.01),11 −3.6 mm Hg (−20%) (p<0.01),13 −4.4 (−21%) (p=0.012)4 and −7.9 mm Hg (−32%) (p<0.001)16 after 1 year. After a mean follow-up of 6 years, Ritch et al 17 did not find any significant IOP change as compared with baseline (+0.2 mm Hg), similar to Peterson et al ,4 who found a −1.6 mm Hg (p=0.38) non-significant IOP variation.…”

“…Singh et al 12 had the lowest success rate with 46% of patients with angle widening. Junqueira et al 11 found a posterior trabecular meshwork visible on 180° without indentation on gonioscopic examination for 90% of eyes after the laser procedure. Ramakrishnan et al 16 were the only authors to focus on PAS, reducing the median number of clock hours with PAS from 3.75 (2.00–6.50) to 2.50 (0.75–5.00) (p<0.001).…”

“…In studies with at least 1 year of follow-up, weighted IOP decreased from 19.6 mm Hg at baseline to 15.6 mm Hg at the last visit after ALPI, providing a −4.0 mm Hg or −20% IOP variation 4 11–13 16. In the studies with a 6-year follow-up, weighted mean IOP varied from 18.7 mm Hg to 18.5 mm Hg at the last visit after ALPI, providing a −0.2 mm Hg or 1% variation4 17 (figure 2).…”

“…To date, there have been no randomised controlled trials evaluating the use of iridoplasty in chronic angle-closure caused by PIS. We included seven retrospective case series4 9–15 and one prospective observational case–control study16 published between 2004 and 2017. The study characteristics are described in table 1.…”

Hidden mechanisms beyond the pupillary block in acute angle closure: ultrasound biomicroscopic study

“…Reported incidences of PL in AAC eyes were from 2.5% to 6.3% . PL accounts for a large proportion of non‐pupillary block component of angle closure in subjects of non‐Asian ethnicity . Our findings suggest that PL rarely elicits AAC by itself in this Asian population.…”

Iridoplasty for plateau iris syndrome: a systematic review

“…After ALPI, IOP decreased from −6.7 mm Hg (−30%) after 1 month15 to −2.8 mm Hg (−19%) (p=0.01),12 −3.4 mm Hg (−19%) (p<0.01),11 −3.6 mm Hg (−20%) (p<0.01),13 −4.4 (−21%) (p=0.012)4 and −7.9 mm Hg (−32%) (p<0.001)16 after 1 year. After a mean follow-up of 6 years, Ritch et al 17 did not find any significant IOP change as compared with baseline (+0.2 mm Hg), similar to Peterson et al ,4 who found a −1.6 mm Hg (p=0.38) non-significant IOP variation.…”

“…Singh et al 12 had the lowest success rate with 46% of patients with angle widening. Junqueira et al 11 found a posterior trabecular meshwork visible on 180° without indentation on gonioscopic examination for 90% of eyes after the laser procedure. Ramakrishnan et al 16 were the only authors to focus on PAS, reducing the median number of clock hours with PAS from 3.75 (2.00–6.50) to 2.50 (0.75–5.00) (p<0.001).…”

“…In studies with at least 1 year of follow-up, weighted IOP decreased from 19.6 mm Hg at baseline to 15.6 mm Hg at the last visit after ALPI, providing a −4.0 mm Hg or −20% IOP variation 4 11–13 16. In the studies with a 6-year follow-up, weighted mean IOP varied from 18.7 mm Hg to 18.5 mm Hg at the last visit after ALPI, providing a −0.2 mm Hg or 1% variation4 17 (figure 2).…”

“…To date, there have been no randomised controlled trials evaluating the use of iridoplasty in chronic angle-closure caused by PIS. We included seven retrospective case series4 9–15 and one prospective observational case–control study16 published between 2004 and 2017. The study characteristics are described in table 1.…”