COMPARISON OF EYELID ANGLE MEASURED USING MANUAL AND DIGITAL IMAGE ANALYSIS METHOD

Abstract

Aim: To compare the eyelid angle measured by using a manual method (Using protractor) and digital image analysis method (Using ImageJ software) at different distances of eye gaze. Methodology: This prospective cross-sectional study was conducted in the preclinical lab at Manipal College of Health Professions. Subjects with no eyelid abnormalities were included in the study and they were asked to fixate at different distances a) at 3 metre (Distance gaze) b) at 70 cm (Intermediategaze) and c) at 40 cm(Near gaze). Using a protractor, the eyelid angle measurements were repeated at various distances which comprised the manual measurement. In the image analysis method, images were captured during distance, intermediate and near gaze using smartphone placed on theside of the face. These images were then analysed using ImageJ software for determining eyelid angle using image analysis method. Palpebral fissure height, Palpebral fissure width, Interpupillary distance, Intercanthal width, Binocular width, Height of open upper lid were some additional anthropometry measurements that were done using meter scale and PD ruler. Results: The mean age of the participants was 20±0.5 years. Anthropometry measurements of the eyelid and Palpebral fissure were done using meter scaleand PD ruler. The mean and standard deviation of the measured parametersare as follows Interpupillary distance: 60.95±2.37 mm, Endo Inter canthal distance: 32.20±2.39 mm, Exo Inter cantal distance: 95.50±3.80 mm, Palpebralfissure height_OD: 12.11±1.32 mm, Palpebral fissure height_OS:12.16±1.46mm, PFW_OD: 32.00±1.10 mm, PFW_OS: 32.11±1.24 mm, Height of upper eyelids_OD: 10.26±1.66 mm and Height of upper eyelids_OS:10.42±1.83 mm. In the right eye, there was no statistically significant difference (p>0.05) between manual protractor method and digital image analysismethod at distance but there was a statistically significant difference (p<0.05)between manual protractor method and digital image analysis method atIntermediate and near. In left eye, there was statistically significant difference(p<0.05) between manual protractor method and digital image analysis method at all three distances. Conclusion: There is a significant difference in eyelid angle measured using manual protractor method and digital image analysis method. The measurement of eyelid angle serves as a critical reference point during cosmetic and reconstructive surgical interventions of the eyelid and accurate measurements are essential for preoperative assessment, surgical planning and postoperative evaluation. Hence more studies on the validation of the anthropometry measurements and eyelid angle using digital image analysis areessential to use digital image analysis in routine eye care practice.