With the development of modern medical technology, the accuracy and safety of refractive surgery in ophthalmology have been constantly improved. Many new examination methods have been applied in research and clinical practice, and anterior segment optical coherence tomography (AS-OCT) is a new non-contact non-invasive optical image diagnosis technology, which can be used to measure the biological structure of anterior segment. AS-OCT is widely used in the clinical diagnosis and treatment of corneal diseases, cataracts, glaucoma and other specialties due to its advantages of fast scanning speed, deep layer, high penetration rate and high resolution. In addition, AS-OCT can also obtain: corneal thickness, corneal epithelial thickness map, corneal topographic map, anterior chamber depth (ACD), white to white (WTW), crystal arch height (LV), Angle width of the anterior chamber, etc., so it is especially suitable for the pre-operative screening, design of operation scheme and safety evaluation after the operation of auxiliary ophthalmic refractive surgery (including corneal refractive surgery and intraocular refractive surgery). At present, corneal refractive surgery mainly includes excimer laser in-situ keratomileusis (LASIK), femtosecond laser-assisted LASIK (FS-LASIK), femtosecond laser stromal lens removal for small incision (SMILE), and transepithelial laser keratoplasty (T-PRK), and ICL implantation is the main method of intraocular refractive surgery. This article will review the clinical application of AS-OCT in corneal refractive surgery and intraocular refractive surgery, and provide reference for clinical practice.

AIM: The early visual qualities of patients were evaluated after small incision lenticule extraction (SMILE) using different optical zones based on dark pupil diameters.METHODS: A case-control study was conducted to include 49 myopic patients (96 eyes) who underwent SMILE surgery. Patients were divided into three groups according to the difference between the diameter of the optical zone and the diameter of the dark pupil: Group A (<0 mm, N=30), Group B (0-1 mm, N=36), and Group C (>1 mm, N=30). In all groups, the dark pupil diameter was measured preoperatively. Subjective visual quality, uncorrected vision acuity (UCVA), spherical equivalent (SE), modulation transfer function cut-off frequency (MTFcutoff), objective scattering index (OSI), simulated contrast visual acuity (VA100%, VA20%, VA9%), total corneal higher-order aberration (tot-HOA), corneal spherical aberration (totZ40) and corneal coma (tot-coma) were measured preoperatively and 3 months postoperatively. P< 0.05 was considered statistically significant.RESULTS: There were no statistically significant differences in age, sex, UCVA, SE, corneal higher-order aberration, OQAS or subjective visual quality among the three groups before surgery (P>0.05). At 3 months postoperatively, there was no significant difference in UCVA, SE, MTFcutoff, OSI, VA100%, VA20%, or VA9% among the three groups (P>0.05). However, the tot-HOA, totZ40 and tot-coma indexes and the changes in corneal higher-order aberrations (Dtot-HOA, DtotZ40, Dtot-coma) at 3 months postoperatively were as follows: Group A > Group B > Group C (P<0.05). At 3 months postoperatively, the difference in subjective visual quality between the three groups was statistically significant (P<0.05). The difference in the amount of change in subjective visual quality between Groups A and C was statistically significant (P<0.05).CONCLUSION: Although the difference between the diameter of the optical zone and the diameter of the dark pupil does not affect the VA or the same diopter of patients after SMILE myopia correction, the optical zone diameter should be greater than the dark pupil diameter as far as possible in the design of SMILE surgery, in order to improve the objective visual quality and subjective satisfaction of patients after surgery.