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Craig A. Woods, Nancy J. Keir, Michael Woods, Lyndon W. Jones; The Development Of A New Grading Scale For In Vivo Front Surface Contact Lens Deposits. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4700.
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The grading of soft contact lens (SCL) deposits has historically relied upon the use of visual descriptors (eg ‘protein’; ‘lipid’) which do not necessarily reflect their true biochemical composition. The introduction of silicone hydrogel materials, which deposit in a different manner to conventional SCL materials, has resulted in increased interest in grading deposits in a clinical setting. The purpose of this study was to develop a novel grading system that accurately reflected the type and extent of the deposits observed on SCL materials.
The grading system included severity (0-4 in 0.5 steps), location (central, peripheral or both) and type (discrete, film or both). Thirty in vivo videos of deposited SCL were graded by a group of 10 experienced clinical researchers. An agreement between investigators of ± 0.5 grade was targeted to select 8 representative videos that corresponded to each grade of severity. An additional 6, which had the highest number of investigator’s agreement (>90%), were selected to represent the location and type of deposit.
Investigator agreement on the grade of severity ranged from 0.5 to 2.5 across the 30 videos, indicating that some videos were more difficult to grade. Reasons for poor agreement were typically related to the criteria used to define deposit location, or the presence of filmy deposits (either alone or in combination with discrete deposits). For the 8 videos chosen to represent the various grades of severity, descriptive statistics are provided in Table 1.
Results from this examination permitted the development of a new grading system for SCL deposits. Future work will include implementation of this system in clinical studies to better assess its utility and it is hoped that the representative videos will improve consistency between investigators when grading SCL deposition.
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