Small-incision lenticule extraction is the latest advancement in the field of keratorefractive surgery. It involves the creation of an intrastromal lenticule that is subsequently removed to correct a refractive error.
Diffuse lamellar keratitis and severe stromal keratitis have been reported following small-incision lenticule extraction.1,2 We report a case that presented with a sterile stromal infiltrate after the procedure.
A 41-year-old man presented to the refractive service at our hospital seeking refractive correction. The corrected distance visual acuity was 20/20 in both eyes with −3.75 sphere in the right eye and −3.75 −0.50 × 160 in the left eye. The ocular and medical examinations were unremarkable. There was no evidence of blepharitis or meibomian gland dysfunction. The patient did not have a history of contact lens use. Corneal tomography (Oculus Pentacam, Optikgerate GmBH) was within normal limits, with a minimum corneal thickness of 547 μm and 541μm in the right eye and left eye, respectively.
Small-incision lenticule extraction was performed using the Visumax (Carl Zeiss Meditec AG) femtosecond laser system. Lenticules of 75 μm and 84 μm were created in the right eye and left eye, respectively, to correct the refractive errors. The procedure was uneventful, with no evidence of bleeding from the corneal side cut intraoperatively. The postoperative treatment regimen included moxifloxacin 0.5% ophthalmic solution 4 times a day, loteprednol etabonate 0.5% in tapered doses, and polyethylene glycol and propylene glycol 0.3% 6 times a day. On the first postoperative day, the uncorrected distance visual acuity (UDVA) was 20/20 in both eyes with a clear interface.
One week postoperatively, the patient presented with complaints of mild discomfort and redness in the right eye. The UDVA was 20/30 and 20/20 in the right eye and left eye, respectively. Slitlamp evaluation showed a semicircular peripheral infiltrate in the right eye extending from the 2 o'clock to 9 o'clock positions (Figure 1). The infiltrate was denser peripherally and faded centrally. The lesion was present outside the area of the femtosecond treatment, with a clear intervening zone between the infiltrate and the limbus. No overlying corneal epithelial defect or anterior chamber reaction was noted. Diffuse granular interface haze of grade 2 diffuse lamellar keratitis was present.
An immune-mediated etiology was suspected based on the clinical presentation, and corneal scrapings were deferred. Blood serology was performed and was negative for human immunodeficiency virus and hepatitis B and C antigen, rheumatoid factor, and antinuclear antibodies. Erythrocyte sedimentation rate and C-reactive protein were within normal limits. A regimen of prednisolone acetate 1.0% ophthalmic suspension hourly, moxifloxacin 0.5% ophthalmic solution 4 times a day, and oral prednisolone 40 mg a day was started.
Three days after the regimen was started, a reduction of the circumcorneal congestion was noted. The peripheral infiltrate appeared less dense; a slight clearing was seen along the edges (Figure 2). The infiltrate continued to resolve over the next 2 weeks, leaving a slight subepithelial haze, and the interface cellularity reduced significantly. Steroid treatment was tapered over 4 weeks. On the final follow-up visit at 2 months, the cornea was clear, with no scarring, and the UDVA was 20/20 (Figure 3).
Several reports have described presumed sterile infiltrates following refractive procedures.3,4 However, to our knowledge, this is the first report of a sterile infiltrate following small-incision lenticule extraction. Increased manipulations of meibomian secretions and release of heat-shock proteins are some of the hypotheses for the development of a sterile infiltrate.5,6
Our case involved a healthy man with no clinical or serological evidence of connective tissue disorder. Ocular examination was unremarkable, with no evidence of blepharitis or meibomian gland dysfunction.
Although the exact mechanism of this complication remains unclear, recognizing the entity and differentiating it from infectious keratitis is essential for appropriate management. Corneal scrapings were deferred in our case because the clinical picture was strongly suggestive of a sterile etiology, with absence of epithelial defect or surrounding edema and a quiet anterior chamber. However, a high degree of clinical suspicion should be maintained.
None of the authors has a financial or proprietary interest in any material or method mentioned.
Zhao J, He L, Yao P, Shen Y, Zhou Z, Miao H, Wang X, Zhou X. Diffuse lamellar keratitis after small-incision lenticule extraction. J Cataract Refract Surg 2015; 41:400-407
Guindolet D, Elluard M, Badaoui A, Stephan S, Doan S, Cochereau I, Gabison EE. Unusual severe interface inflammation after uneventful small incision lenticule extraction. J Refract Surg 2016; 32:855-857
Ambrósio R Jr, Periman LM, Netto MV, Wilson SE. Bilateral marginal sterile infiltrates and diffuse lamellar keratitis after laser in situ keratomileusis. J Refract Surg 2003; 19:154-158
Lahners WJ, Hardten DR, Lindstrom RL. Peripheral keratitis following laser in situ keratomileusis. J Refract Surg 2003; 19:671-675
Rao SK, Fogla R, Rajagopal R, Sitalakshmi G, Padmanabhan P. Bilateral corneal infiltrates after excimer laser photorefractive keratectomy. J Cataract Refract Surg 2000; 26:456-459
Teichmann KD, Cameron J, Huaman A, Rahi AHS, Badr I. Wessely-type immune ring following phototherapeutic keratectomy. J Cataract Refract Surg 1996; 22:142-146