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Sarah M. Simpson, Daniel C. Warder, Angela Moore, Isabella Irrcher, Delan Jinapriya; Refractive Status In Patients With Narrow Angles. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6374.
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To evaluate the prevalence of myopia in patients with narrow angles, to compare ocular biometric parameters, and to determine the effect of laser peripheral iridotomy (PI) on myopic and hyperopic patients with narrow angles or primary angle closure glaucoma (PAC).
This study is a retrospective comparative study with prospective data collection of biometric parameters. We reviewed the charts of 272 consecutive patients who received a PI in the Department of Ophthalmology at Queen’s University, Kingston, Ontario by reviewing provincial billing data between August 2006 to March 2011. After excluding for non-narrow angle related PIs (n=26) and those without refractive data at the time of PI (n=22), 224 patients were identified. These patients were classified as myopic (spherical equivalent (SE) ≤ 0 D) or hyperopic (spherical equivalent > 0 D). Immersion A-scan to determine ocular biometry was performed prospectively on available myopic (n = 36) and hyperopic (n = 45) narrow angle patients having had a PI within the last 24 months.
Of the 224 narrow angle patients 28% (n=62) were myopic and 72% were hyperopic (n=161). Ninety-eight patients (44%) had a refractive status between 0 D and +2 D. Four patients (2%) were highly myopic with a SE greater than 5 D of myopia. A-scans revealed longer axial lengths in myopic patients (p < 0.001) but no difference in lenticular thickness or anterior chamber depth between the 2 groups. A PI was effective in deepening anterior chamber angles in both groups, with no significant difference in the amount of opening post-PI between groups.
More than 25% of a consecutive series of 224 patients with narrow angles were myopic in our study population. Furthermore, almost half were only mildly hyperopic. Our data points to a high prevalence of narrow angle patients traditionally not thought to be at risk for narrow angle glaucoma. This stresses the importance of evaluating all glaucoma patients for narrow angles regardless of refractive status.
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