Horizontal Palpebral Fissure Best Predicts Subjective Facial Asymmetry in Unilateral Anophthalmia/Microphthalmia

Congenital anophthalmia/microphthalmia are developmental eye disorders with variable severity. The absence of a normal-sized eye can cause facial asymmetry. Outcome is often reported as relative horizontal palpebral fissure (rHPF) and/or orbital dimensions. Yet, the predictive value of these measurements is unknown. This study aims to test the relation between facial and ultrasound measurements and subjective outcomes.

In this retrospective study, 3D facial scans of 31 patients with unilateral an/microphthalmia were analyzed. The scans were obtained using the Vectra scanner, and measurements were taken using GOM Inspect software. Various facial landmarks were identified, including horizontal palpebral fissure (HPF), lower lid, upper eyelid, lid crease, and inferior eyebrow margin. Orbital width, orbital height, and axial eye length were measured using ultrasonography. Ratios between the affected and unaffected sides were calculated from these measurements. Faces were also subjectively rated for the degree of asymmetry on a scale of 1 to 5.

Average subjective judgment showed a significant association with, respectively, rHPF ( p < 0.001), caudal placement of the eye ( p < 0.001), orbital width ( p = 0.001), pretarsal show asymmetry ( p = 0.003), and axial length ( p = 0.003). After a forward selection procedure, only rHPF predicted the subjective outcome. rHPF was strongly correlated with the other significant factors.

The results indicate that the rHPF is best associated with subjective outcome. The forward selection procedure showed that adding ultrasound or other facial measurements did not result in a better association.