• Biometric Factors Associated With Acute Primary Angle- Closure

    By Marianne Doran and selected by Deepak P. Edward, MD

    Journal Highlights

    Investigative Ophthalmology & Visual Science
    2016;57(13):5320-5325

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    Atalay et al.
    compared ocular biomet­ric and anterior segment parameters between the affected eye and fellow eye in 76 subjects with unilateral acute primary angle closure (APAC) who had undergone bilateral laser peripheral iridotomy before enrollment. The au­thors found that APAC eyes had smaller anterior segment dimensions than the fellow eyes. They also discovered that iris thickness is a strong predictor of angle width in both affected and fellow eyes.

    The researchers used anterior seg­ment optical coherence tomography with customized software to measure the following: angle opening distance (AOD750); trabecular–iris space area (TISA750); iris thickness (IT750); iris curvature (ICURV); iris area (IAREA); anterior chamber depth, area, and vol­ume (ACD, ACA, and ACV); anterior chamber width (ACW); anterior vault (ACD+LV); lens vault (LV); and pupil diameter (PD). A-scan ultrasonography was used to measure axial length (AL) and lens thickness (LT). Mean differ­ences in ocular biometric and anterior segment parameters were assessed with linear mixed model adjustment for PD.

    In this cross-sectional study, 53 participants (36 females, 67.9%) with a mean age of 62.7 years were analyzed, after exclusion of 17 patients with unanalyzable images in at least 1 eye. Eyes affected by unilateral APAC had a shallower ACD and a smaller ACA, ACV, anterior vault, TISA750, AOD750, and ICURV (all comparisons, p < .05). In the affected eyes, IT750 was signifi­cantly associated with AOD750, where­as in the fellow eyes, IT750 and AL were predictive of AOD750 (all p < .05). Axial length, ACW, LV, LT, IAREA, and IT750 did not differ between the eyes.

    The researchers noted that the mean ACD was, on average, 11.7% smaller in affected eyes when compared with fellow eyes, and they suggested that narrower angles and smaller anterior chamber parameters exacerbate angle crowding in such eyes. In addition, they identified a novel association between iris thickness and angle width in this study, accounting for approximately one-third of the variability in AOD750.

    The original article can be found here.