A 72-year-old woman notices blurry vision for several weeks OD. Her ocular history is notable for uncomplicated cataract surgery OU 5 months ago. Her vision at her last visit 2 months prior was 20/25 OU. On today’s exam, her BSCVA is 20/40-2 OD and 20/25 OS, IOP and pupillary response are normal. Slit lamp exam shows clear corneas with no fluorescein staining. The anterior chambers are deep and quiet and there is a PC IOL in each eye. The posterior capsule is clear OU. Posterior segment exam is normal and there are posterior vitreous detachments OU. However, retroillumination reveals irregularity of the corneal surface OD > OS, and corneal topography (CVK) is obtained.
The CVK map clearly demonstrates the elevated area of epithelium superiorly causing irregular astigmatism. Reexamination of the corneas at the slit lamp confirmed irregular epithelial regions with negative staining, which involved the visual axis OD. This is consistent with anterior basement membrane dystrophy (map-dot-fingerprint dystrophy) of the cornea.
The patient underwent a superficial keratectomy at the slit lamp with a blunt spatula to remove the abnormal epithelium and a bandage contact lens was placed. When the eye had healed, the corneal topography improved as shown below, and her vision returned to 20/25 OD.
Discussion: This case of ABMD reinforces the importance of careful evaluation of the ocular surface. The most common causes of decreased vision after cataract surgery include dry eye/MGD, corneal edema, rebound iritis, posterior capsular opacity, and CME. This patient had good vision 3 months following surgery so it would be unusual to see new corneal edema, iritis, or CME at this point in an eye without additional risk factors. There was no PCO on exam, so the etiology of the decreased vision is most likely related to an abnormality of the ocular surface. This was eventually demonstrated by careful examination of the cornea, which showed subtle signs of pathology, and the diagnosis was reconfirmed with CVK. The two most common complications of ABMD are recurrent erosion syndrome and visual distortion (due to irregular astigmatism in the central cornea), both of which can be treated with epithelial debridement (although RES due to ABMD usually also requires anterior stromal puncture, diamond burr polishing, or PTK).