Development of Definitive and Reliable Grading Scales for Meibomian Gland Dysfunction

PurposeTo develop and validate grading scales for meibomian gland dysfunction (MGD) that allow consistent diagnosis of MGD and are suitable for clinical studies.DesignDevelopment and validation study of grading scales.MethodsLid margin and meibomian gland photographs were taken in the multicenter, prospective cross-sectional study for MGD and control subjects. New grading scales for MGD signs (abnormal lid margin findings of vascularity, plugging of gland orifices, lid margin irregularity, lid margin thickening, partial glands, and gland dropout) in both upper and lower eyelids were developed. Three MGD experts, 3 general ophthalmologists, and 3 non-physicians independently tested the scales by evaluating photographs. The levels of interrater and intrarater agreement for each grading scale were estimated with the use of kappa statistics.ResultsThirty-eight patients with MGD and 20 control subjects were enrolled and photographed. New grading scales were developed using a total of 226 photographs. The interrater kappa values for MGD experts and for general ophthalmologists and non-physicians with reference to an MGD expert ranged from 0.36 to 0.87 (median of 0.66), 0.41 to 0.73 (0.60), and 0.30 to 0.77 (0.59), respectively. Those for intrarater reliability for 2 MGD experts ranged from 0.49 to 0.93 (0.82).ConclusionsNew grading scales for MGD signs were developed and found to have appropriate inter- and intrarater reliabilities for grading MGD. These grading scales are suitable for MGD diagnosis and application to multicenter trials.