Abstract:AIM: To analyze the changes in binocular visual function before and after small incision lenticule extraction(SMILE)in patients with different degrees of myopia.METHODS:A prospective non-randomized controlled study was conducted. A total of 94 patients(188 eyes)who visited the refractive outpatient department of the ophthalmology department of the General Hospital of the PLA from June 2022 to June 2023 and voluntarily chose SMILE were consecutively included. They were grouped according to the degree of myopia, including 24 cases(48 eyes)in the low myopia group(-3.00 D<SE≤-0.50 D), 40 cases(80 eyes)in the moderate myopia group(-6.00 D<SE≤-3.00 D), and 30 cases(60 eyes)in the high myopia group(SE≤-6.00 D). The preoperative spherical equivalent(SE)and binocular visual function, including near and far horizontal phoria, near and far horizontal fusional range, near point of convergence(NPC), positive/negative relative accommodation(PRA/NRA), binocular cross-cylinder(BCC), monocular and binocular accommodative facility(M/BAF), and amplitude of accommodation(AMP), among the three groups of patients were compared.RESULTS:At 1 wk, 1 and 3 mo preoperatively, the SE of both eyes of the patients in the three groups was better than that before operation(all P<0.05). In the low myopia group, the recovery point of the positive fusional convergence at a far distance first increased after the operation and then decreased to approach the level before the operation(P=0.043). In the moderate myopia group, the break point of the positive fusional convergence at a far distance gradually decreased after the operation(P=0.014), and it was the lowest at 3 mo after the operation(all P<0.05); the recovery point first increased after the operation and then decreased to approach the level before the operation(P=0.042). In the high myopia group, the horizontal phoria at a far distance after the operation was improved compared with that before the operation(P=0.01); the break point of the positive fusional convergence at a far distance gradually decreased after the operation(P=0.017), and it was the lowest at 3 mo after the operation; the NPC first decreased and then increased after the operation compared with that before the operation(P=0.038), and the NPC shifted farther at 3 mo after the operation compared with that at 1 wk after the operation(P<0.008); the BAF after the operation gradually increased compared with that before the operation(P=0.032).CONCLUSION:SMILE can effectively improve myopic refractive errors in patients and has good predictability and stability; it has a certain improvement effect on the binocular visual function of low, moderate, and high myopia, especially for the accommodative and convergence functions of patients with high myopia to varying degrees.
