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Optom Vis Sci. 2016 Mar;93(3):300-4. doi: 10.1097/OPX.0000000000000800.

Neophyte Skill Judging Corneoscleral Lens Clearance.

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*OD, FAAO †OD ‡BS The Eye Center, Southern College of Optometry, Memphis, Tennessee (DGF, BS); and the Lasik Vision Institute, San Bruno, California (NC).



This study examines the accuracy of neophyte clinicians' assessments of central corneal clearance (CCC) of a corneoscleral lens using lens center thickness (CT) as a biometric scale.


A normal participant was fit with a corneoscleral lens on both eyes. Observers (n = 34) from the final semester of their fourth year in optometric clinical training were instructed to estimate the amount of CCC through the approximate geometrical center of the lens using a standardized script which included a photograph identifying various zones. Observer estimates were then compared against anterior segment-OCT (AS-OCT) values obtained during calibration.


Mean observer estimates of central corneal clearances were OD 220.5 ± 121.microns (range 50 to 480 microns) and OS 398.0 ± 159.1 microns (range 140 to 800 microns). The mean AS-OCT values were OD 105.5 ± 11.microns (range 84 to 121 microns) and OS 340.8 ± 15.2 microns (range 315 to 362 microns). Mann-Whitney test was statistically significant for comparison of median values OD (177.0; p = 0.001) and OS (260.0; p = 0.012).


Neophyte clinicians in the final semester of their fourth year of optometric clinical training tend to significantly overestimate the amount of CCC in a normal subject with declining accuracy as the amount of clearance diminishes.

[Indexed for MEDLINE]

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