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Off-axis photoscreening: A critical review of the literature

1 October 2001


Pur,pose: This review compares the data from several studies relating to the Medical Technology Innovations photoscreener (MTI) to determine the sensitivity and reliability of the device.

Results: Our analysis reveals potential benefits, as well as limitations of the device. The MTI is good at detecting constant strabismus (95-100% sensitivity), media opacities (20-100% sensitivity) and anisometropia greater than 1.00 diopter (100% sensitivity). However, the MTI lacks consistency in its findings for myopia (56.3% PPV), hyperopia (20-80% sensitivity), astigmatism (41.4% PPV), anisocoria (0-100% sensitivity), and alternating or intermittent strabismus (23-50% sensitivity). Also, the studies used different criteria to obtain their data, making it difficult to relate the studies to each other. This inconsistency prevents a definite conclusion about the capacity of t he MTI.

Conclusion: The MTI is a convenient and portable vision screening tool that can be used by lay people to detect constant strabismus greater than 10.00 prism diopters, media opacities and anisometropia greater than 1.00 diopter, with 100% accuracy. However, much of the clinical study data does not support its validity, reliability or cost effectiveness. Further studies with consistent parameters are needed to determine the current value of the MTI as a visual health-screening tool.


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