Effectiveness of Adjuvant Treatment with Argon Laser plus Standard Therapy in Refractory Infectious Keratitis

To evaluate the effectiveness of argon laser phototherapy as an adjunctive treatment to standard medical therapy for refractory infectious keratitis.

We report the results of a retrospective interventional case series. Patients diagnosed with infectious keratitis with no clinical response to standard medical therapy who were referred for corneal photocoagulation with an argon laser at the Asociación Para Evitar La Ceguera (APEC) in Mexico City from May 2022 to March 2024, were included. Diagnosis was based on clinical and microbiological evaluations. Argon laser corneal photocoagulation was performed by applying sodium fluorescein, followed by laser using a wavelength of 530 nm, power of 900-950 mW, spot of 250 μm, and a pulse duration of 0.2 s. Survival analysis was performed to determine the difference in corneal epithelial healing time with and without the presence of hypopyon.

Thirty eyes (30 patients) with a mean age of 49.9 ± 14.9 years (SD) were included. 66.7% were male. Fungal infections were found in 43.4% of patients, and Gram (+) bacterial infections in 20.0%. Hypopyon was present in 33.3% (n = 10). A total of 43.3% of eyes (n = 13) were treated with a combination of 5% natamycin, 0.5% netilmicin, and 1% voriconazole. Four eyes underwent surgical treatment with conjunctival flap (one eye) and penetrating keratoplasty (three eyes). The median preoperative uncorrected visual acuity was 2.00 ± 0.7 (logMAR), which improved to 1.30 ± 0.8 (logMAR) after treatment. No statistically significant association was found between the germ type and epithelialization time (p = 0.35). The presence of hypopyon was associated as a risk factor for delayed corneal epithelialization (p < 0.01).

The use of argon laser photocoagulation plus standard topical treatment in patients with refractory infectious keratitis can be considered a safe and accessible adjuvant therapy in daily ophthalmic practice. The presence of hypopyon was associated with delayed corneal healing and could be considered a risk factor for severe complications.