Small incision lenticule extraction or SMILE is a simple laser eye surgery. It is a minimally invasive procedure for treating refractive errors like astigmatism, hyperopia, presbyopia, and myopia. It is performed on adults in the age group of 18 to 40 years. This comparative study assesses the influence of age on surgical outcomes.

The retrospective study relied on 53 consecutive patients with 102 matched eyes for evaluating the refractive outcomes after myopic SMILE. The patients underwent preoperative evaluation as well as post-operative ones after 1 and 6 months. They were divided into two groups with age<= 35 and age>= 40 years. The efficacy, predictability, safety, and astigmatic changes were measured as the main outcomes. Their differences were subjected to vector analysis using ASSORT software.

The pre-op evaluation revealed no differences in astigmatism or spherical equivalent (SE) in the two groups. But six months after SMILE, the older group’s mean astigmatism worsened significantly. The SE was disregarded, and their refractive cylinder tended towards under-correction. After six months, the efficacy and safety indexes also showed statistically significant differences. The younger group’s scores were 1.07 and 1.11, while the older adult’s scores were 0.97 and 1.04.

The post-SMILE outcomes in patients over 40 years were acceptable but poor. The astigmatic change, safety index, and efficacy score were meager. The adult eye showed a tendency to under-correction when compared with younger patients. Corneal stroma stiffness increases in older adults. It can reduce SMILE’s remodeling capacity and weaken the visual and refractive outcomes.