Collagen crosslinking using riboflavin and UVA led to a significant change in the swelling behavior of the anterior stroma, confirming prior findings that the crosslinking effect is strongest in the anterior half of the stroma. Crosslinked cornea did not induce a specific signal on OCT, and OCT is therefore not suited for clinical controls of the crosslinking effect.

No author has a financial or proprietary interest in any material or method mentioned.

Background: Collagen cross-linking of the cornea has been shown by us to have an antiedematous effect in the cornea. The aim of the present study was to examine if this effect can be used for the treatment of bullous keratopathy. Methods: This clinical interventional case series included 3 patients (3 eyes) with bullous keratopathy due to pseudophakia, corneal transplant rejection, and Fuchs’ endothelial dystrophy. After dehydration for 1 day using 40% glucose, the central 8 mm of the cornea were abraded and cross-linked with the photosensitizer riboflavin and UVA (370 nm, 3 mW/cm²) for 30 min. Optical coherence tomography pachymetry measurements of the central cornea were performed at various time intervals. Results: Corneal thickness was reduced by 90.33 ± 17.04 μm on average 3 days after cross-linking and by 93.67 ± 14.22 μm after 8 months. The bullous changes of the epithelium were markedly improved, resulting in loss of pain and discomfort. Visual acuity was significantly improved in the case without prior stromal scarring. Conclusions: Cross-linking might become another useful tool in the treatment of bullous keratopathy. It is primarily suited for patients with pain symptoms, restricted visual prognosis or to extend the time interval for an upcoming corneal transplantation.

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Online OCP was suitable for continuous measurements of corneal changes caused by dehydration. These dehydration effects should be particularly considered in refractive corneal surgery.

In this experimental evaluation, online OCP revealed to be a precise and reproducible method to assess the central corneal thickness and its changes intraoperatively. This could be important to monitor incisional and excimer laser-based corneal refractive procedures, such as PRK or LASIK.

Online OCP allowed a clinical evaluation of intraoperative ablation parameters in LASIK. Further studies are needed to assess a possible active control of the excimer laser ablation from these continuous values, which could possibly improve current ablation nomograms.

This study provides further validation that anterior segment optical coherence tomography is a reliable method to assess important parameters for diagnosis and therapeutic outcome control of patients with keratoconus. This method may be particularly useful as a safe and well-defined preoperative diagnostic tool before keratoplasty or corneal cross-linking.