Photochemical corneal collagen cross‑linkage using riboflavin and ultraviolet A for keratoconus and keratectasia

Infections were reported in 8 single case reports. In 4 of these patients there was no major long-term adverse impact, visual acuity was reduced in 1 patient and no further details were reported in 3 patients.

Sterile keratitis associated with scarring or loss of vision or needing keratoplasty was reported in 3% (4 out of 117) of patients in a case series of 117 patients. This was treated with high-dose topical or subconjunctival corticosteroids and 2 patients had a persistent decrease in best corrected visual acuity (BCVA). Deep stromal infiltrates with scarring at 2 months despite treatment with antibiotics was reported in a single case report.

Stromal scar developed in 4 patients (3 cases in 1 study); in 3 patients, the uncorrected visual acuity (UCVA) increased significantly despite scars, and in the other patient visual acuity was corrected with a lens.

Corneal oedema within 24 hours after corneal collagen cross‑linkage (CXL) and inflammation for 2 to 3 weeks, iris atrophy and pigment dispersion were reported in a case series of 10 patients. These resolved in 1 patient and improved in 4 patients after treatment. Corneal oedema that developed in a single case report resolved after 6 months' treatment but scarring and poor visual acuity remained.

Corneal melting was reported in 1 single case report. This patient was initially treated with tissue glue and bandage contact lens application but needed penetrating keratoplasty on day 12. Perforation due to corneal melting was reported in 2 single case reports. These patients were treated by penetrating keratoplasty and antibiotics with no long-term adverse impact.

Corneal burn and ulcer were reported in 3 single case reports; 1 patient was treated by phototherapeutic keratectomy (corrected visual acuity [CVA] improved from 20/69 to 20/20 at 28 months) and treatment details were not reported for the other 2 patients.

Corneal haze with diffuse subepithelial opacification and paracentral corneal thinning associated with scarring was reported in a single case report. This disappeared only gradually despite intensive therapy.

Stromal haze was reported in all eyes in a randomised controlled trial of 10 patients comparing same-day intracorneal ring segment (ICRS) and CXL with ICRS and CXL 6 months later. This resolved eventually in both groups (the time period was not reported). Mild posterior linear stromal haze at 1 month after CXL with photorefractive keratectomy (PRK) was reported in 46% of eyes (13 out of 28) in a case series of 28 eyes (23 patients). At 12 months follow-up, this had decreased in density but had not completely disappeared.

The specialist advisers listed anecdotal adverse events as delayed epithelial healing, bilateral corneal infection and transient recurrent erosion syndrome. In addition, a specialist provided information about a single occurrence of corneal perforation after the procedure.