Green Thermal Laser Applicable in Resistant Infectious Keratitis

Close-up of an eye with dendritic keratitis, showing branch-shaped corneal lesions caused by herpes simplex infection.
01APAM7A – Close-up of an eye with dendritic keratitis, showing branch-shaped corneal lesions caused by herpes simplex infection. Keratitis is the inflammation of the cornea of the eye.
Treatments with the technique are both safe and effective when used as an adjunct to medication, the study shows.

Resistant infectious keratitis (IK) may be safely and effectively treated by green thermal laser adjunct therapy, according to results of a retrospective case series, published in Clinical Ophthalmology.

Patients (N=150) treated for resistant IK at Tanta University Ophthalmology Hospital in Egypt between 2016 and 2020 were included in this study. Resistant IK was defined as no signs of improvement (reduced corneal infiltration, corneal edema, hypopyon level, and epithelial defect) after 7 days. All patients received green thermal laser treatments to the cornea after antimicrobial therapy. Patients were assessed daily for 7 days and every 3 days thereafter until complete re-epithelialization was achieved.

Patients were aged mean 46.2±7.7 years, 32% were women, 84% had previously received topical antimicrobial treatment, and IK was most frequently caused by either trauma (66%) or contact lenses (22%).

Corneal ulcers had a mean diameter of 4.33±1.3 mm vertically and 4.38±0.85 mm horizontally. Most ulcers (68.6%) had a hypopyon level of mean 2.36±1.0 mm. Culprit organisms included fungal (29.3%), bacterial (23.3%), or a mixture of fungal and bacterial (47.3%) organisms.

During adjunct laser treatment, between 28 and 350 (mean, 178±66) pulses were applied per session.

Within a week of treatment, the investigators observed improvement among 92% of patients.

Few patients (n=12; 8%) required a second laser treatment at 1 week.

Amniotic membrane transplantation was required by 26 (17.3%) patients due to second laser treatment (n=12), progressive corneal thinning (n=11), and laser-induced corneal micro-perforation. Tectonic corneal graft was required by 2 (1.3%) patients due to uncontrolled inflammation-induced corneal macro-perforation.

Complete re-epithelialization occurred among 82% of patients within 2.87±0.7 weeks of the laser treatment.

This study was limited by its retrospective design and absence of a comparator or control condition.

The researchers report that patients with resistant IK caused by fungal or bacterial organisms, or both, could be safely and effectively treated with green thermal laser adjunct therapy.


Nasef MH, El Emam SY, Sharaf AF, Allam WA. Adjunctive green thermal laser photocoagulation for treatment of resistant infectious keratitis. Clin Ophthalmol. 2021;15:2447-2453. doi:10.2147/OPTH.S312674