Pressure-Induced Interlamellar Stromal Keratitis After Small-Incision Lenticule Extraction Procedure: A Case Report

To report a case of pressure-induced interlamellar stromal keratitis (PISK) after small-incision lenticule extraction (SMILE) for the correction of myopic astigmatism in the United States.

We report the case of a 27-year-old man who underwent uneventful SMILE surgery and presented with pressure-induced stromal keratitis. Anterior and posterior segment examination, uncorrected distance visual acuity, refraction, intraocular pressure, and pachymetry values are reported from this time period.

Three weeks postoperatively, examination revealed new-onset central corneal haze and edema in both eyes, more significant in the right eye. The patient was given a presumptive diagnosis of diffuse lamellar keratitis. Intensive corticosteroid treatment was administered, causing a significant decline in uncorrected distance visual acuity OD from 20/25 to 20/250 and OS from 20/20 to 20/60, with a significant myopic shift of -3.0 D and -1.0 D, respectively. In our case, pachymetry measurements revealed 78 μm OD and 43 μm OS of additional corneal thickness. Pressure readings were 25 mm Hg OD and 19 mm Hg OS, respectively. He was diagnosed with PISK, and after 4 days of steroid discontinuation and Brimonidine-Timolol administration, his symptoms had improved with resolution of corneal edema.

Clinicians should be aware that PISK is a potential complication of SMILE. Postoperative intraocular pressure measurements are an important aspect of the management of postcorneal refractive surgery patients because the differentiation of PISK from diffuse lamellar keratitis, as well as the early detection and treatment of PISK, can avoid severe complications.