This study demonstrated that in patients with Graves' upper eyelid retraction, multiple radial midpupil distance measurement allowed precise determination of lid contour deformities and clearly showed the angular position where the retraction was more pronounced.
The authors used custom software to analyze monocular palpebral fissure images from 35 patients with Graves' upper eyelid retraction and 30 normal subjects. Initially, the user subjectively determined the pupil center on the computer screen. The software then drew the conventional midpupil lip distance (MPLD) vertical line (90°) and six radial lines 15° apart from the midline in the temporal (105°, 120°, 135°, 150°, 165°, and 180°) and nasal (75°, 60°, 45°, 30°, 15°, and 0°) sectors of the lid fissure.
The MPLDs increased from the vertical midline in both nasal and temporal sectors of the fissure. In the control group, the differences between the mean central MPLD (90°) and those up to 30° in the nasal (75° and 60°) and temporal sectors (105° and 120°) were not significant. For greater eccentricities, all temporal and nasal mean MPLDs increased significantly. When the MPLDs of the same angles were compared between groups, the mean values of the Graves' patients differed from controls at all angles (F = 4192; P < 0.0001). The greatest temporal/nasal asymmetry occurred 60° from the vertical midline.
It would be more interesting to perform such evaluations in pre- and postoperative blepharoptosis patients and patients with eyelid deformations. In the latter, the eyelid may have a normal contour and still have other abnormalities, such as eyelid scars or eyelash disorders. Evaluation in different races also would be interesting. The authors did not address patients with irregular or eccentric pupils, nor did they differentiate between the pupil center, the visual axis and the corneal center.
The authors note that they have no proprietary interest the software employed in this study and a user-friendly version is being prepared for free download. They emphasize that radial MPLD measurement can be used for any condition that induces contour abnormalities, such as ptosis, postoperative lid abnormalities and congenital lid deformities.