Macular corneal dystrophy and posterior corneal abnormalities

Purpose: This study reports the presentation of 2 families with macular corneal dystrophy (MCD). The aim of this study was to show whether ultrasound biomicroscopy (UBM) can, based on posterior changes of the cornea in MCD, assist in the choice of surgery, either anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PK), compared with optical coherence tomography (OCT) and Scheimpflug. Methods: Six patients with MCD were examined for their best-corrected visual acuity, slit-lamp, OCT, UBM, and Scheimpflug findings. Blood samples for DNA and exons of the CHST6 gene were screened for mutations. Results: All 6 patients showed typical MCD signs at the slit lamp. Corneal transplantation was required in 2 patients in both eyes. Recurrence of MCD was observed in 2 eyes after the DALK procedure (patient A5, age 48 years, right eye and B1, 51 years, left eye), whereas the 2 eyes after PK (patient A5, age 48 years, left eye and patient B1, 51 years, right eye) remained clear (for 10 years of follow-up in patient A5 and 4 years in patient B1). In 2 patients (A1 and A3), corneal thinning could be evaluated by OCT. In 3 patients (A2, 3, and 4), UBM disclosed deeper pathologies including opacities, loss of continuity, and focal protrusions of the posterior cornea, which were not evident by other devices. In family A, a novel mutation was identified. Conclusions: Our UBM examination of MCD shows alterations of the cornea's posterior layer and confirms the known clinical and histological findings of MCD that PK represents the therapy of choice, contrary to DALK. The novel CHST6 mutation shows the heterogeneity of MCD.