Repeatability and reproducibility of upper eyelid measurements.

AIM The aim of this study was to assess the repeatability and reproducibility by physicians of upper lid measurements and to investigate the influence of clinical experience on the learning curve effect. METHODS Both eyes of 22 outpatients were assessed for three basic measures of ptosis: marginal reflex distance (MRD) for upper and lower lids, upper lid skin crease (SC), and levator function (LF). Patients with variable eyelid positions were excluded. The patients were measured twice by a consultant and once by each of a clinical fellow, a specialist registrar, and a senior house officer in random order. Each observer was masked to their colleagues' results and followed a standard measurement protocol. Data were analysed using Bland-Altman plots. RESULTS Consultant repeatability was high and consistent, the median difference between measures being 0 for each of the four parameters. Clinically acceptable reproducibility was shown in all measurements for even the least experienced physician and was particularly consistent for extreme observations. There was evidence of a learning curve effect. CONCLUSIONS These results suggest that interobserver and intraobserver variability in assessment of upper lid ptosis using a standard measurement protocol is low and clinically acceptable when the technique of assessment is standardised.