Premium
A method for a rapid objective measurement of eye deviation angle in both strabismus and phoria
Author(s) -
Yehezkel O.,
Spierer A.,
Oz D.,
Yam R.,
Belkin M.
Publication year - 2017
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2017.0t054
Subject(s) - strabismus , repeatability , heterophoria , optometry , test (biology) , standard deviation , medicine , ophthalmology , minimum deviation , prism , strabismus surgery , audiology , orthodontics , computer science , mathematics , statistics , optics , geology , paleontology , physics
Purpose Strabismus is usually treated by corrective surgery of the extraocular muscles, the parameters of which mainly depend on the misalignment measurement and hence on its precision. The current strabismus angle measurement (prism cover test) hasn't changed since the eighteenth century. This test is time‐consuming, cumbersome, severely limited by the child's cooperation, subjective and highly dependent on the examiner's skill and experience. Studies have shown a very high inter‐examiner variability in measurement results. Moreover, the angle of strabismus itself may vary over time and the current low‐efficiency test does not allow for multiple testing of the same patient, thus reducing the test's accuracy. Increasing the measurement accuracy and efficiency may reduce the number of reoperations and will improve results of strabismus surgery, prism prescriptions and orthoptic therapy and monitoring. Methods We are evaluating the accuracy and repeatability of NovaSight's novel strabismus angle measurement method using an automatic and objective system based on eye tracking, in comparison to the prism cover test results. Results A group of 23 adult subjects (average age 26.8 ± 4.6 years) with eye deviations, heterotropia and heterophoria, were tested by both the automatic and the manual tests in a masked fashion by two experienced optometrists. The clinical trial results show a high correlation of over 88% between the presented automatic test and the golden standard prism cover test while a significant difference in standard deviation was found, the repeatability of the automated test is twice as high as that of the manual test. Conclusions The system increases the examination accuracy and thus may reduce the number of strabismus reoperations. The system also reduces chair time significantly and has the potential to become the new standard of care.