Abstract
Purpose: :
To determine changes in lens vault (LV) in Asian Indian eyes with angle closure after laser iridotomy (LPI).
Methods: :
In this prospective observational study, subjects with primary angle closure were enrolled. All subjects underwent gonioscopy and imaging with Fourier-domain source-swept optical coherence tomography (Casia, Tomey, Japan) before and after LPI. LV was defined as the perpendicular distance between the anterior pole of the crystalline lens and the horizontal line joining 2 scleral spurs (SS). It was measured manually, after marking SS, in horizontal and vertical scans. Lenstar LS 900 (Haag-Streit, USA) was used to measure anterior chamber depth, axial length and lens thickness.
Results: :
Fifty-four eyes (42 subjects) were analyzed. Mean age was 59.1 ± 9.0 years (range 40 to 78 years). None of the eyes had peripheral anterior synechiae prior to LPI. LV was found to increase significantly after LPI in vertical scans (774.7 µ, 95% C.I, 704.1 to 845.4, vs. 723.1 µ, 95% C.I, 667.1 to 779.1) (p<0.01), but showed no change in horizontal scans (710.2 µ, 95% C.I, 644.3 to 776.2, vs. 704.3 µ, 95% C.I, 636.9 to 771.7) (p<0.7). Multivariate linear regression showed that gender might influence the LV difference after LPI in the vertical aspect (p=0.007). Intra-class correlation for intra-observer reliability for measuring LV was 0.87 (95% C.I, 0.74-0.92). The spur to spur distance also showed significant change in the vertical quadrant (p = 0.01) but not in the horizontal quadrant (p = 0.9).
Conclusions: :
Although there was a significant change in the vertical LV after LPI, this could have been due to the fact that one might mark the SS in a different location in a open angle compared to a closed angle. A larger sample is required to determine other parameters that might change LV after LPI.
Keywords: laser • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • anterior segment