Abstract
Purpose :
To evaluate temporal change in anterior chamber angle anatomy following laser peripheral iridotomy (LPI) in patients with primary angle closure by comparison with the untreated fellow eye. Additionally, the effect of LPI treatment on diurnal intraocular pressure (DIOP) fluctuation (maximum-minimum IOP) was investigated.
Methods :
Thirty-nine patients newly diagnosed with bilateral primary angle closure (PAC) or primary angle closure suspects (PACS) were recruited and received LPI to one eye. The other eye acted as a control and intraocular pressure (IOP) was measured hourly with Goldmann applanation tonometer during DIOP assessments. Angle opening distance (AOD), trabecular–iris angle (TIA), angle recess area (ARA), and trabecular–iris space area (TISA) at both 500 mm and 750 mm from scleral spur were measured over 8 sections with swept source anterior segment optical coherence tomography (AS-OCT) at pre-determined intervals.
Results :
An increase in all angle parameters following LPI treatment was observed, which was maintained for 6 months (e.g inferior segment AOD500 0.0402mm (p=0.008) at 1 week and 0.0396mm (p=0.003) at 6 months) following LPI procedure. The greatest effect was observed opposite the iridotomy site in the inferior and infero-temporal sections (AOD500 0.0396mm, p=0.003 and AOD750 0.0751mm, p=0.002), while the angle parameter at the site of iridotomy at the superior section increased comparably to the overall angle changes (AOD500 0.0129mm, p=0.057 and AOD750 0.022mm, p=0.006) at 6 months post LPI. There were no statistically significant differences for the overall IOP or DIOP fluctuation values in the treated group at 6 months post-LPI. For both treated and untreated groups there was no statistically significant reduction in average IOP or DIOP fluctuation at 6 months compared to baseline.
Conclusions :
LPI widened all angle sections with maximum effect observed in the site opposite the iridotomy. Angle parameter changes were maintained up to 6 months after LPI treatment without any statistically significant change in DIOP fluctuation.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.