Late-onset keratitis following LASIK has a similar clinical course to non-LASIK keratitis and may possibly be treated similarly to microbial keratitis without LASIK, according to a study in the Journal of Cataract and Refractive Surgery.
Researchers reviewed a series of patients from a 5-year period between 2012 and 2016 with presumed microbial keratitis and a prior LASIK surgery from Sydney, Australia, with a goal of understanding the clinical features and microbiology that might assist clinicians in this patient population.
The final cohort included 16 eyes from 16 patients (9 women; median age 41.5 years). All patients had prior LASIK surgery, with a median estimated time between surgery and keratitis presentation of 38.3 months (IQR, 6.7-77.45). Median time between symptom onset and presentation at the hospital was 3 days, and length of hospital stay was a median of 4.5 days.
Researchers identified the presence of predisposing factors in 68.8% of patients; 8 had a single risk factor, and 3 had 2 or more risk factors. Risk factors included immunosuppressive diseases such as asthma, thyrotoxicosis, and diabetes.
Ten of 16 patients had ulcer size information available. Mean size was 8.8 mm2, with a mean size of infiltrates of 3.6 mm2 in 7 patients. Three patients had a hypopyon, 1 patient each had a ring infiltrate, corneal thinning, and epithelial ingrowth under the flap.
Corneal scrape results had positive cultures in 75% of patients, 12.5% of whom had polymicrobial infections. Of the 14 organisms that were isolated, 85.7% were Gram-positive and 14.3% were Gram-negative. The most common initial antibiotic regimen was fortified antibiotics with cefalotin 5% and gentamicin 0.9% (62.5% of patients). Combination cefalotin and ofloxacin was used in 12.5% of patients, while ofloxacin monotherapy was used in 4 patients. Fourteen patients required topical corticosteroid use.
Median time to last follow-up was 25 days (range, 3 days to 168 days), and median time to ulcer healing was 18 days (range, 2 days to 40 days). Final visual acuity was available for 11 patients, who experienced a median visual acuity improvement of 0.41 to 0.3 logMAR. Eight patients experienced a final visual acuity of 6/12 or better.
Five patients experienced complications, 2 of whom required tectonic keratoplasty. Two patients with slow-healing epithelial defects required a bandage contact lens. No patients required flap lift or antibiotic irrigation.
Study limitations include those inherent to retrospective studies, including incomplete data retrieval, and a potential skewing of cases due to the hospital being a quaternary referral center.
“The organisms identified, risk factors, and clinical course were similar to microbial keratitis occurring in patients without prior LASIK,” the research concludes. “Clinicians will benefit from knowing that late-onset keratitis after LASIK could potentially be treated like microbial keratitis occurring without prior LASIK.”
Galal A, Artola A, Belda J, et al. Late onset of microbial keratitis following laser in situ keratomileusis surgery. A case series. J Cataract Refract Surg. Published online January 21, 2021. doi:10.1097/j.jcrs.0000000000000581