New Refractive Approach for Patients with Diabetes

LASIK and accelerated CXL safe in myopic diabetic patients. Dermot McGrath reports

LASIK combined with accelerated corneal cross-linking (CXL) appears to offer a safe and effective treatment modality in diabetic myopic patients, according to the results of a study presented at the ESCRS Virtual Winter Meeting.

“Although a longer follow-up is needed to confirm these results, our study indicates LASIK in combination with CXL is safe on the corneal endothelium of diabetic myopic patients,” Mohamed Mahmoud MD told a Cornea Day session.

LASIK is usually considered a relative contraindication in diabetic patients due to the pathologic changes in the cornea of these patients, he said. Furthermore, the immune response is weak, and wound healing is delayed when these patients require more follow-up.

Simultaneous LASIK and accelerated CXL (LASIK Xtra) are now used in many countries around the world on patients at high risk of post-LASIK ectasia and regression, such as those with high degrees of myopia, younger patients, and those with low residual stromal bed thickness, Dr Mahmoud noted.

He next turned to the context of diabetes mellitus (DM), one of the most morbid chronic diseases affecting millions of patients globally. Dr Mahmoud said the disease could reduce endothelial cell density (ECD) and the percentage of hexagonal cells present but also increase the coefficient of variation (CV)—indicating diabetes causes instability in the corneal endothelial cells.

Dr Mahmoud’s prospective comparative interventional case series included 120 eyes of 60 myopic patients treated with LASIK combined with accelerated CXL. LASIK was performed first with the M-2 microkeratome (Moria, France) to create a 110-micron flap, followed by stromal ablation with the excimer laser. The stromal bed was instilled with 0.1% riboflavin in a 20% hydroxymethyl propyl cellulose solution for two minutes before returning the flap to its original location according to the alignment marks. The cornea was exposed to UVA light for three minutes with a wavelength of 366–374 nm and an irradiance of 30 mW/cm2 .

Patients were divided into two groups: group A included 60 eyes of diabetic patients, while group B had 60 eyes of non-diabetic patients. The corneal endothelium was evaluated by specular microscope preoperatively and after three and six months postoperatively. Postoperative treatment was topical antibiotic for one week, a topical anti-inflammatory for two weeks, and topical artificial lubricant for one month or more as needed.

Dr Mahmoud noted the endothelial cell density (ECD) showed statistically significant changes after three and six months postoperatively in group A while group B showed statistically significant changes after three months without significant change after six months. Furthermore, both groups improved close to preoperative density levels, with no significant differences between them, at the end of six months of follow-up.

Corneal endothelial cell morphology—as determined by polymegathism and pleomorphism values—showed a statistically significant difference in diabetic patients after six months, with no significant change evident in the non-diabetic patients.

Summing up, Dr Mahmoud said LASIK with accelerated CXL seemed to be safe and effective for diabetic patients with myopia, but further studies with longer follow-up are required to confirm his group’s findings.

“Although a longer follow-up is needed to confirm these results, our study indicates LASIK in combination with CXL is safe on the corneal endothelium of diabetic myopic patients.”

This study was presented at the ESCRS Virtual Winter Meeting 2022. Mohamed Mahmoud MD, Department of Ophthalmology, Faculty of Medicine, Minia University, Minia, Egypt. Mohamed_Zaki@mu.edu.eg