Efficacy of accelerated transepithelial crosslinking in patients with bullous keratopathy

Relevance Bullous keratopathy (BC) is a corneal disease associated with dysfunction of endothelial cells, leading to stromal edema and bullous changes. Causes: eye trauma, ophthalmological surgeries, endothelial dystrophies. Complaints: decreased vision, pain, lacrimation and photophobia [1, 2]. The "gold standard" of treatment is endothelial keratoplasty, but it is contraindicated in concomitant terminal glaucoma, autoimmune diseases or optic nerve atrophy [3]. Corneal collagen crosslinking (CXL) with riboflavin and UV radiation is a minimally invasive method that increases the strength of the cornea [4]. Within a few months after the intervention, fibrous changes in the stroma and a decrease in corneal thickness occur, in connection with which it was proposed to use CXL in patients with BC. However, in CD, its effectiveness is short-term (for 1-6 months) due to stromal edema, which hinders the penetration of riboflavin. Objective Evaluation of the results of accelerated transepithelial CXL with intrastromal riboflavin injection in CD. Material and methods The study involved 15 patients aged 54 to 83 years with CD (15 eyes). Accelerated transepithelial CXL with intrastromal riboflavin injection (0.1%) was performed under local anesthesia. A syringe with riboflavin on a thin needle bent at an angle of about 30° and oriented at 15° to the corneal surface with the beveled side up was inserted into the stroma paralimbally alternately at two points (at 3 and 9 o'clock) to a level of 70% of the corneal thickness, about 0.15 ml of the drug was injected. Then UV radiation (6 mW/cm2) was applied for 15 min. The operation was completed by instillation of an antibacterial drug. A contact lens was not installed. Results The postoperative period (9 months) was uneventful. In most patients (80%), pain did not recur within 9 months (p < 0.032). The average corneal thickness in the central zone (CCT, initially 885.5 ± 95.8 μm) significantly decreased and amounted to 694.5 ± 78.8, 673.2 ± 97.4, 666.7 ± 88.1 and 654.4 ± 99.5 μm after 1; 3; 6 and 9 months after the intervention, respectively [5]. At the last control, the CTR was on average 231.1 ± 122 μm less than the initial values ​​(p < 0.02). No changes in IOP were observed (p > 0.05). Conclusion Accelerated CXL with intrastromal riboflavin injection is a safe and effective method for pain relief and corneal thickness reduction in BC. Randomized studies with a larger number of patients are needed. Key words: corneal crosslinking; bullous keratopathy; endothelial dystrophies; transepithelial crosslinking; Fuchs' dystrophy