Evaluation of Corneal Morphology in Patients With Hemifacial Spasm

To determine whether the corneal topographic parameter values, individual corneal layer thicknesses, and its endothelial layer morphology are different in patients with hemifacial spasm (HFS) than in the control contralateral eye.

This study was designed as a prospective study. Among patients who applied to our hospital within the past 3-year period, those with HFS in one eye (study eyes) and a completely normal contralateral eye (control eyes) were included in this study. In addition to a complete ophthalmologic examination, all patients were scanned by the Pentacam Scheimpflug camera, and a corneal endothelium cell count was taken using a Topcon Specular Microscope. Also, the thickness of the corneal sublayers was measured on the central cornea with anterior segment module of spectral domain optical coherence tomography. Data entered using SPSS software were then evaluated by paired t test; P<0.05 value was considered statistically significant.

Twenty-eight patients (16 women and 12 men) were evaluated. Steep K, Kmax, and astigmatism values were significantly higher in the study eyes of patients with HFS than in the control eyes (P<0.05, for all). In addition, the total corneal thickness and corneal stromal thickness measurements in the study eyes were statistically significantly thinner than the control eyes (P=0.04 and P<0.001, respectively). Specular microscopy parameters were not statistically significant between the study eyes and control eyes (P>0.05, for all).

Corneal stromal thinning suggests that chronic exposure to hypoxia may induce this effect through extracellular matrix remodeling and losses in collagen framework content in patients with HFS.