Treatment of Keratoconus With Advanced Corneal Crosslinking

Treatment of Keratoconus With Advanced Corneal Crosslinking

The purpose of this study was to determine whether mechanical compression of the cornea during corneal crosslinking for keratoconus using a sutured rigid contact lens can improve the optical outcomes of the treatment.

The study is designed as a prospective, open, randomized controlled trial involving patients aged 18-28 years of both genders with uni- or bilateral keratoconus planned for routine corneal crosslinking at the Department of Ophthalmology, Umeå University Hospital, Umeå, Sweden. The study involves 30+30 eyes with keratoconus, which are randomized to receive either conventional corneal crosslinking (n=30) using the Dresden protocol or a modified treatment - corneal reshaping and crosslinking (n=30), where a rigid contact lens is sutured to the cornea during the treatment to flatten the corneal curvature and potentially improve the optical outcome after the treatment. Patients are randomized utilizing a list of unique random numbers between 1 and 60. All patients are informed about the procedures before consenting to participate in the study. The study also involves 60 eyes of healthy age- and sex-matched control subjects.

At baseline, before treatment, each eye is evaluated with autorefractometer measurement, best spectacle-corrected LogMAR visual acuity, Pentacam Scheimpflug photography, Goldmann applanation tonometry and biomicroscopy. The corneal biomechanical characteristics are assessed with applanation resonance tonometry and the ocular response analyzer. The investigations are repeated at 1 month, 6 months, 2 years and 5 years after the treatment.

Inclusion Criteria:

• Patients planned for corneal crosslinking.
• Progressive keratoconus documented with Scheimpflug photography using the Pentacam Scheimflug camera and/or repeated subjective refraction and keratometry.
• A keratoconus diagnosis based on the Amsler-Krumeich grading and the "Total Deviation" KC quantification value from the "Belin-Ambrosio enhanced ectasia" measurements of the Pentacam Scheimpflug camera, and an altered red reflex and/or an irregular cornea seen as distortion of the keratometric mires.
• Minimum corneal thickness of 400 µm at the thinnest point after epithelial removal.
• 18-28 years of age
• No ocular abnormalities except keratoconus
• No previous ocular surgery
• No cognitive insufficiency interfering with the informed consent.

Exclusion Criteria:

• Age under 18 or over 28
• Any corneal abnormalities except keratoconus
• Previous ocular surgery
• Cognitive insufficiency.