Abstract
Purpose:
To determine whether prophylactic laser iridotomy (LI) in patients with anatomically narrow angles can cause a change in refractive errors.
Methods:
This retrospective study evaluated eyes that underwent LI for anatomically narrow angles over a two-month period at the Yale Eye Center. Only individuals who had primary anatomical narrow angles and an auto-refraction before and after LI within a four-week time period were included. Acute angle closure or secondary angle-closure due to any other ocular conditions such as neovascular or uveitic etiologies was excluded. The auto-refraction measurements before and after LI were converted to their respective spherical equivalents in order to be analyzed. Central corneal thickness and axial length were also evaluated. For patients with both eyes meeting the inclusion criteria, data from only one eye was used, based on randomization by coin toss. Pre- and post-LI refractive errors were compared using paired t-test.
Results:
Ten eyes from 10 patients were included (age 59.4±11.7). The average pre-LI spherical equivalent was +1.86±0.59 diopters (D). The average post-LI spherical equivalent was +1.76±0.53D. The mean of difference was -0.09±0.08D, with a 95% confidence interval of -0.3 to +0.09. No significant difference was demonstrated in the spherical equivalents of auto-refractions before and after LI (p=0.30). The average central corneal thickness for all patients was 559.5±41.7μm. The average axial length was 23.01±1.38mm.
Conclusions:
These results suggest that LI does not cause significant refractive changes in patients with anatomically narrow angles. Patients may be counseled that LI will unlikely affect their refractive status. Further investigation with a larger number of patients is indicated.