Grading Contact Lens Complications: The Effect of Knowledge on Grading Accuracy

Abstract

2Purpose: Grading contact lens complications is a time-effective process which, if performed accurately, may improve patient management significantly. Multiple factors have been identified that influence grading accuracy, such as the knowledge, training and experience of the observer. The aim of this study was to further explore the effect of knowledge on grading accuracy, both in terms of intensity and specificity, and to do so by avoiding the need to require the subjects to interpolate between whole number grades. Material and Methods:Optometry students were divided into three knowledge groups according to their academic progress and in such a way that knowledge intensity and specificity could be evaluated separately. A vertical visual analogue scale was devised to allow subjects to grade three different conditions of medium severity (position 50 of the scale) from the Institute for EyeResearch grading scale, mainly, bulbar hyperaemia, limbal vascularisation and lid redness.Results: Bulbar hyperaemia was graded lowest (mean = 21.5; SD = 1.4), followed by limbal vascularisation (mean = 40.7; SD = 1.6) and lid redness (mean = 51.2; SD = 1.3) and these differences were found to be statistically significant (ANOVA p = 0.000). Knowledge was found to influence the grading process, resulting in statistically significant differences in the overall grading performance of the three knowledge groups (ANOVA, p = 0.048). Furthermore, even if knowledge intensity failed to improve grading accuracy over a certain threshold, a combination of knowledge intensity and specificity resulted in an enhancement of the homogeneity of the grading data. Conclusions: Knowledge intensity and specificity both contribute to improve grading skills, albeit through different mechanisms. An intermediate knowledge of contact lens complications is required to attain good grading accuracy and a basic training in pathology is also advised. ABSTRACTContact lens complications; Grading scales; Grading accuracy; Interpolation skills; Knowledge KEY WORDS 3The grading of contact lens complications is a complex and essential process that stems from the need to correctly identify the severity of a condition and, therefore, to allow for the most appropriate form of treatment. The prognosis of many contact lens complications depends on the ability of the clinician to decide upon the actual severity and urgency of the condition and to act accordingly, either through treatment or referral.

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