This article is more than 5 years old. Information may no longer be current.
Speaker shares pearls for topography-guided PRK, cross-linking for keratoconus
Click Here to Manage Email Alerts
NEW ORLEANS — Raymond Stein, MD, FRCSC, shared pearls for performing topography-guided photorefractive keratectomy in combination with corneal cross-linking for the management of keratoconus here at Cornea Day preceding the American Society of Cataract and Refractive Surgery meeting.
“This technique can arrest the disease and improve best corrected spectacle visual acuity,” Stein said.
Raymond Stein
Cross-linking alone to improve best corrected spectacle visual acuity (BCSVA) and quality of vision is not as effective as when topography-guided PRK is added, he said.
Stein advises colleagues to make an accurate diagnosis of keratoconus.
“You do not want to subject nonkeratoconus patients to surgical intervention. To make an accurate diagnosis, you need topography, and you need a proper slit lamp examination,” he said.
The best candidates for topography-guided PRK in combination with cross-linking are those with clear corneas, reduced BCSVA, reasonable corneal thickness greater than 450 µm and topographic changes that enter into the pupillary zone, as well as less than 10 D difference across the cornea.
Keratoconus patients with cataracts may benefit from topography-guided PRK before cataract surgery to decrease astigmatism, “Because following their cataract surgery, they may be able to discontinue their RGP [rigid gas permeable] lenses,” Stein said.
Tissue removal with topography-guided PRK does not increase the risk of ectasia when performed in combination with cross-linking, at least in the short term, he said.
In a study including 345 eyes with an average follow-up of 26 months up to 4 years, there was one case of progression treated with repeat cross-linking.
“Complications can occur but are generally uncommon,” Stein said.
The most common ocular adverse event was corneal haze greater than mild, which occurred in 4% of patients who had a very high diopter difference across the cornea.
The most effective treatment zone for topography-guided PRK is 6.0 mm and 6.5 mm because it creates greater corneal stability and less chance of regression of effect.
“Smaller zones are associated with a lower chance of regularizing the cornea and improving BCSVA,” Stein said.
In another study including 96 eyes of 52 patients aged 9 to 15 years old, progression developed in one eye that required repeat cross-linking.
“Topography-guided PRK and cross-linking can be successful in younger patients with a low incidence of progressive ectasia,” he said. – by Nhu Te
Reference:
Stein R. Topography-guided PRK and corneal cross-linking. Presented at: ASCRS; May 6-10, 2016; New Orleans, Louisiana.
Disclosure: Stein reports no relevant financial disclosures.