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Editors Selection IGR 7-1
Clinical Examination Methods: Swimming goggles and IOP
Comment by Chris Johnson on:
70091 Visual Field Testing with Head-Mounted Perimeter 'imo', Matsumoto C; Yamao S; Nomoto H et al., PLoS ONE, 2016; 11: e0161974
For many years, perimetry and visual field testing were performed manually using either a tangent screen, an arc perimeter or a hemispheric bowl perimeter.1 Approximately 40 years ago, this procedure was modified to be performed in an automatic fashion under computer control.1 There have been modifications to the software and hardware of automated visual field devices, development of age-adjusted normative databases, and analysis procedures for identifying detection and progression of visual field loss, but the basic components of automated visual field testing have remained relatively similar to the initial devices. In this publication, Dr. Matsumoto and his colleagues describe the development and evaluation of a unique and innovative approach to this diagnostic test consisting of a head-mounted perimeter, and have compared the results obtained from it with a widely used clinical automated perimeter.
Forty eyes of 20 glaucoma patients, stratified by degree of glaucomatous visual field loss (mild, moderate and severe) were tested with the head mounted perimeter 'imo' and the Humphrey Field Analyzer, using the 30-2 stimulus presentation pattern. The two test procedures demonstrated very high correlations (0.96 or higher) and highly comparable gray scale graphical plots. There are several distinct advantages to the head-mounted display: (1) it is portable and can be easily used by most patients; (2) it has both staircase and Bayesian (ZEST) testing procedures; (3) by presenting stimuli randomly to each eye separately it can test both eyes at once; (4) eye and pupil tracking functions are available. Additionally, the authors have considered many possible difficulties associated with this type of testing and have appropriately addressed them.
This appears to be a paradigm changing approach to this diagnostic test procedure. It can be used under nearly any type of test setting (waiting room, home use, remote geographical areas, etc.) and will undoubtedly open up more flexible opportunities for practitioners to obtain results from this perimetric procedure, and possibly allow multiple patients to be tested at once, with results collected by a computer server. The correlations are most impressive, but it will be instructive to determine if other clinical sites are able to achieve these results. The question of whether the 30-hertz rate will be sufficient to achieve good eye tracking is also a consideration. I enthusiastically applaud the authors for their innovative, careful and thorough approach, and believe that this represents the wave of the future for this technology related to diagnostic visual field testing.
References
- Johnson CA, Wall M, Thompson HS. A history of perimetry and visual field testing. Optom Vis Sci 2011;88:8-15.
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