Measurements of the periocular facial area with Web-based software.

We developed a simple Web-based program to make measurements on displayed photographs between several ocular and periocular landmarks. The measurements were: (1) vertical distance between the margin of the upper and lower eyelids (palpebral aperture), (2) distance between the lower eyelid margin and the inferior corneal margin (palpebro-limbar distance); (3) interpupillary distance; (4) ocular proptosis. We measured the distances using the Web program and compared them with manual measurements on the subject's face. The measurements involved 102 eyes of 51 patients with a variety of ophthalmic conditions. There was good agreement between manual and computer measurements. For example, for manual measurements in 49 patients, we obtained interpupillary distances ranging from 45 to 69 mm (mean 61, SD 6), whereas for computer measurements we found values ranging from 42 to 49 mm (mean 59, SD 6). The mean of the differences between manual and computer measurements was -2.0 mm (SD 4.3) and the 95% limits of agreement were -6.5 to 10.5 mm. Thus, computer measurements tended to give a higher reading by between 0.8 and 3.2 mm (95% confidence interval for the difference). Web-based software may be used to perform measurements on two-dimensional pictures and the technique appears to be suitable for telemedical purposes.