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Bonny Lee, Timothy Peiris, Dan Liu, David Atherton, Bernard C Szirth, Robert D Fechtner, Albert S Khouri; Are disposable and standard gonioscopy lenses comparable?. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4671.
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© ARVO (1962-2015); The Authors (2016-present)
Gonioscopy is important in the evaluation and treatment of glaucoma. Disposable gonioscopy lenses have recently been introduced in an effort to minimize risks of infection, avoid re-sterilization of equipment, and meet certain regulatory institutional requirements. The purpose of this prospective comparative clinical study was to compare the quality of images produced by disposable versus standard gonioscopy lenses. We hypothesized that difference in image quality would be insignificant.
21 volunteers were included in the study. A disposable single mirror lens (Sensor Medical Technology, Maple Valley, USA) and a standard reusable lens (Volk G-1, Mentor, USA) were used. Each subject’s left eye was anesthetized with proparacaine hydrochloride ophthalmic solution 0.5%. Each lens was lubricated and placed against the eye to visualize the iridocorneal angle. High resolution images of the inferior and temporal angles of each subject’s left eye were acquired (Haag-Streit IM900 photo biomicroscope slit lamp, Switzerland) through each lens (Fig 1 & 2). 74 images (37 via disposable lens, 37 via standard lens) were graded for clarity and quality by a trained glaucoma specialist using the Spaeth gonioscopic classification system. Clarity was defined as either (1) all structures perceived or (2) all structures not perceived. Quality was defined as (1) all angle landmarks clear and well focused, (2) some angle landmarks clear, others blurred, or (3) angle landmarks could not be ascertained. Clarity and quality values were tallied for each group and we used a two-tailed t-test for statistical analysis.
The average quality of images produced with the standard lens was 1.46±0.56 compared to 1.54±0.61 for those produced with the disposable lens (P=0.55). When evaluating the clarity of the trabecular meshwork as perceived through the disposable lens and standard lens, the mean image score was 1.49±0.51 and 1.47±0.51 respectively (P=0.90).
There is no significant difference in quality of images produced with standard versus disposable gonioscopy lenses. These findings suggest that disposable gonioscopy lenses are an alternative in glaucoma evaluation and treatment, especially when conditions are not available or optimal for use and cleaning of the standard lens.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Figure 1: Image of the inferior iridocorneal angle via standard gonioscopy lens
Figure 2: Image of the inferior iridocorneal angle via disposable gonioscopy lens
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