Corneal ulcers respond to corneal collagen crosslinking therapy
April 1, 2012
Results from patients treated for refractory ulcers due to infectious keratitis show corneal collagen crosslinking is an effective intervention that results in rapid and complete healing.
Orlando, FL-Results from patients treated for refractory ulcers due to infectious keratitis show corneal collagen crosslinking (CXL) is an effective intervention that results in rapid and complete healing, said Anita Panda, MD, at the annual meeting of the American Academy of Ophthalmology.
Dr. Panda reviewed literature reports on the use of CXL for treatment of infectious keratitis and outcomes from two series of prospectively followed patients with corneal ulcers treated at the Dr. Rajendra Prasad Centre for Ophthalmic Science, All India Institute of Medical Sciences, New Delhi, India. An initial series consisted of six eyes, and based on the positive outcomes in those cases, another 31 eyes were treated.
All eyes had a response to CXL except for two eyes in the latter series. For the overall population, re-epithelialization of the cornea began within 2 to 6 days after CXL and was completed within 5 to 10 days. Complete healing of the ulcer was achieved within 3 to 6 weeks.
Since the stiffening effect of CXL is concentrated in the anterior 200 to 300 µm of the cornea, use of CXL for treating refractory infectious keratitis is limited to eyes with an ulcer depth <300 µm, Dr. Panda suggested.
"Sampling for culture and sensitivity testing followed by medical therapy is done first," she said. "If the antimicrobial treatment is deemed appropriate based on the microbiology results and the eye is not improving after 2 weeks, CXL is performed."
The treatment is performed using topical anesthesia with proparacaine 0.5% and removal of the epithelium using a blunt knife. Riboflavin 0.1% drops are instilled over a period of 30 minutes followed by irradiation with 370-nm ultraviolet A light using a dose of 3 mW/cm2 .
Patients being treated for infectious keratitis continue existing topical antimicrobial therapy after the CXL, although the regimen is switched from fortified antibiotic formulations to commercially available products once epithelialization begins. Patients receive cycloplegics and antiglaucoma medications as needed.
In the first series of six eyes, antimicrobial drops had been used for 4 to 12 weeks prior to CXL, one eye had a sealed microperforation, and ulcer diameter ranged from 5 to 8 mm. Preoperative corrected distance acuity was worse than 40/200 in all eyes and improved in all eyes after CXL.
In the second series of 31 eyes, the two eyes that did not have a response had a fungal infection, of which one was associated with viral keratitis. The series also included two eyes with Acanthamoeba keratitis, both of which healed but subsequently one led to phthisis bulbi.