Abstract
Purpose:
Megalocornea is a rare, nonprogressive, bilateral, enlarged corneal diameter (13-18 mm). It has 2 patterns: Simple megalocornea with no other abnormalities and Anterior megalophthalmos. The latter may have: iris dysgenesis, pigmentary dispersion+/- glaucoma, increased anterior chamber depth, enlarged lens/ciliary body, and shortened vitreous length. The purpose of this study is to describe such features pre/post-operatively, and understand potential intraoperative challenges.
Methods:
Retrospective chart review from January 2009 to October 2012 at the Veterans Affairs Boston Healthcare System. Twelve eyes of ten patients were included that had undergone cataract surgery with corneal diameter of at least 13 mm and age >18. Baseline characterisitics were: age, corneal diameter/curvature, axial length, pigment dispersion, glaucoma, retinal detachment, epiretinal membrane. Outcome measures were: best corrected visual acuity, zonular dehiscence, lens placement, retinal detachment.
Results:
Average age was 55.2 (range 46-78). Four eyes had pigmentary dispersion glaucoma and four had retinal detachment, 3 before and 1 after cataract surgery. The average corneal curvature was 42.07 diopters (range 40.59-44.95) and the axial length 25.50mm (range 24.3-26.72). Post op vision: ten with 20/20 (83.3%), one 20/30 and one 20/40; the latter two had epiretinal membranes. Intraoperative challenges were: 1.Dislocation of a primary sulcus lens requiring a second surgery for a sutured lens 2. Iridodenesis/phacodenesis (3 cases) 3. Zonular dehiscence with use of MA50 lens or capsular tension ring (2 cases).
Conclusions:
On average, our patients with megalocornea were younger, have central nuclear cataracts, flatter corneas, and a longer eye. They may present with glaucoma or retinal pathology. Forme fruste megalocornea can be easily missed but must be identified prior to cataract surgery to prepare for intraoperative complexities, such as a deep anterior chambers, weak zonules, and capsular fragility. Sulcus lenses/anterior chamber lenses may not be properly sized and sulcus lenses must be suture fixated. Corneal diameter should be measured as part of standard biometry in order to diagnos megalocornea and optimize surgical outcomes.
Keywords: 445 cataract •
421 anterior segment •
567 intraocular lens