CORNEAL EPITHELIAL INGROWTH AFTER LASIK

To describe a case of corneal epithelial ingrowth (EI) after laser assisted subepitelial keratomileusis (LASIK) monitored with corneal optical coherence tomography (OCT) and corneal topography.

A 46-year-old woman presented with ocular discomfort in her left eye (OS). She reported past history of corneal refractive surgery with LASIK in both eyes 6 years earlier.  Best corrected visual acuity using Log MAR chart was 0.05 in the right eye (OD) and 0.1 in the OS. Refraction values were +0.25 (-1.25 x 76º) in OD, and +0.25 (-1.00 x 33º) in OS. Slit-lamp examination revealed an 8x1mm epithelial corneal irregularity in OS, compatible with post-LASIK EI grade 2. Fluorescein staining was negative and no additional anterior segment alterations were observed. Intraocular pressure and fundus examination were normal in both eyes.

Corneal topography, OCT and anterior pole photographs were performed in both eyes for further monitorization.

The diagnosis of post-LASIK EI was established. A conservative attitude was chosen and artificial tears were prescribed. At the following visits, no progression of the lesion was evidenced and BCVA remained stable. EI is defined by the presence of corneal epithelial cells at the flap interface after LASIK. It is infrequent in primary procedures, but the incidence increases when the flap is raised in reoperations. The etiology is still poorly understood, but poor flap adhesion or apposition may allow migration of surface epithelium into the interface. EI is usually a casual, non-progressive and asymptomatic finding, but could affect vision due to visual axis invasion or secondary irregular astigmatism. In cases of decreased vision or flap melting, mechanical cleaning of epithelial cells and achieving closure of the flap edge to prevent recurrent invasion of epithelium into the flap stromal interface space is indicated. However, the treatment itself constitutes a risk factor for recurrence, so it is not recommended to treat asymptomatic and stable EI. Close monitorization with the aid of corneal topography or OCT is essential for monitoring disease progression.

Post-LASIK EI is an uncommon complication, that remains asymptomatic in many cases. Observation with anterior segment imaging tools such as OCT, serves as a useful investigation in detecting subtle changes that are not readily evident on slit lamp examination.