Orthokeratology lens is an optical correction method mainly used to control the development of myopia in children and adolescents.In recent years, the material and parameter design of orthokeratology lens has been constantly updated and improved.Despite its customizable, well-permeable, and optically superior properties, the ocular surface microenvironment may be affected by multiple factors after a long-term lens wear, resulting in a homeostatic imbalance of the ocular surface microenvironment due to direct attachment of the lens to the ocular surface.As the incidence of myopia in children and adolescents has increased rapidly in recent years, orthokeratology lens has been widely used as a non-surgical treatment to control the refractive growth of myopia.Understanding the influence of long-term orthokeratology lens wear on the ocular surface microenvironment can help avoid the related risk in myopia prevention and control.Therefore, this paper summarizes the effects of orthokeratology lens wear on ocular surface tissues, cells, tear fluid and microbiota, focuses on the potential risks of long-term orthokeratology lens wear, and leads optometrists to give comprehensive consideration to improving safety and effectiveness during the eyesight testing and follow-up.

Orthokeratology lens is an optical correction method mainly used to control the development of myopia in children and adolescents.In recent years, the material and parameter design of orthokeratology lens has been constantly updated and improved.Despite its customizable, well-permeable, and optically superior properties, the ocular surface microenvironment may be affected by multiple factors after a long-term lens wear, resulting in a homeostatic imbalance of the ocular surface microenvironment due to direct attachment of the lens to the ocular surface.As the incidence of myopia in children and adolescents has increased rapidly in recent years, orthokeratology lens has been widely used as a non-surgical treatment to control the refractive growth of myopia.Understanding the influence of long-term orthokeratology lens wear on the ocular surface microenvironment can help avoid the related risk in myopia prevention and control.Therefore, this paper summarizes the effects of orthokeratology lens wear on ocular surface tissues, cells, tear fluid and microbiota, focuses on the potential risks of long-term orthokeratology lens wear, and leads optometrists to give comprehensive consideration to improving safety and effectiveness during the eyesight testing and follow-up.

Objective:To investigate the effects of transepithelial photorefractive keratectomy (TransPRK) and femtosecond small incision lenticule extraction (SMILE) on corneal biomechanics measured by the Ocular Response Analyzer in the early postoperative period.Methods:A cohort study was conducted.The right eyes of 56 patients who underwent TransPRK and 52 patients who underwent SMILE in Dalian Medical University Affiliated Dalian Third People's Hospital from November 2020 to June 2021 were continuously included.The postoperative follow-up was 3 months.The central corneal thickness (CCT) and keratometry (Km) were measured 1 month and 3 months after surgery.The corneal-compensated intraocular pressure (IOPcc), corneal resistance factor (CRF), corneal hysteresis (CH), and 19 repeatable mechanical infrared signal waveform parameters measured by the Ocular Response Analyzer were recorded before the surgery, 1 month and 3 months after the surgery, respectively.The measurement indexs at different time points between two groups were compared.This study adhered to the Declaration of Helsinki and the study protocol was approved by the Ethics Committee of Dalian Medical University Affiliated Dalian Third People's Hospital (No.2019-KT-010). Written informed consent was obtained from each patient before surgery.Results:There was no significant difference in CCT, Km, and IOPcc between the two groups at 1 month and 3 months after the surgery (all at P>0.05). In both groups, CRF, CH, p1area, p2area, p1area1, p2area1, w1, w2, w11, w21, h1, h2, h11, h21, dive1, dive2 and mslew1 were decreased, while path1, path2, path11, and aplhf were increased at 1 month after the surgery compared with before surgery, showing statistically significant differences (all at P<0.05). In both groups, CRF, CH, p1area, p2area, p1area1, p2area1, w1, w2, w11, w21, h1, h2, h11, h21, dive1 decreased, while path1, path2, path11, and aplhf were increased at 3 months after the surgery in comparison with before surgery, showing statistically significant differences (all at P<0.05). In SMILE group, the dive2 were decreased at 3 months after the surgery compared with before surgery, and the difference was statistically significant ( P<0.01). At 1 month after the surgery, p1area, p2area, p1area1, p2area1, w1, w2, w11, w21, dive1 and dive2 were higher, while CH, path1, path2, and path11 were smaller in TransPRK group than in SMILE group, showing statistically significant differences between them (all at P<0.05). At 3 months after the surgery, p1area, p2area, p1area1, p2area1, w1, w2, w11, w21, h2, h21, dive1 and dive2 were higher, while path1, path2, and path11 were smaller in TransPRK group than in SMILE group, showing statistically significant differences between them (all at P<0.05). Conclusions:Corneal biomechanics are weakened after both TransPRK and SMILE.In the early postoperative period, the mechanical infrared waveform parameters measured by the Ocular Response Analyzer are better after TransPRK than after SMILE.

Objective:To investigate the differences and changes in early postoperative visual quality after small incision lenticule extraction (SMILE) and smart pulse technology-assisted transepithelial photorefractive keratectomy (SPT-TransPRK).Methods:A cohort study was performed.A total of 92 patients (92 eyes) who underwent corneal laser refractive surgery were enrolled in Dalian Third People's Hospital Affiliated to Dalian Medical University from February 2021 to May 2021.The data from the right eye were collected for analysis.The patients were divided into SMILE group (40 patients, 40 eyes) and SPT-TransPRK group (52 patients, 52 eyes). Preoperative, 1- and 3-month postoperative visual acuity were measured to calculate the effectiveness, which was defined as the ratio of postoperative uncorrected visual acuity (UCVA) to preoperative best corrected visual acuity.Refraction was measured by an AR-1 autorefractor.Corneal higher-order aberration (HOA) including total HOA, spherical aberration and coma was measured by Sirius corneal topographer.Objective scatter index (OSI), modulation transfer function cut-off frequency (MTF cut-off), Strehl ratio (SR), simulated contrast visual acuity VA100 (day), VA20 (dusk) and VA9 (night) were measured via OQAS II visual quality analysis system.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Dalian Third People's Hospital Affiliated to Dalian Medical University (No.2019-KT-010). Written informed consent was obtained from each subject.Results:There was no significant difference in 3-month postoperative UCVA and effectiveness between the two groups ( Z=0.880, P=0.380; t=0.920, P=0.058). Patients in SPT-TransPRK group showed mild hyperopia 3 months after surgery.Preoperative, 1- and 3-month postoperative total corneal HOA was (0.47±0.18), (0.70±0.22) and (0.74±0.19)μm in SMILE group, and (0.40±0.14), (0.98±0.35) and (0.94±0.22)μm in SPT-TransPRK group respectively, showing statistically significant differences ( Fgroup=13.851, P=0.001; Ftime=29.960, P<0.001). Preoperative, 1- and 3-month postoperative spherical aberration was (-0.20±0.09), (-0.44±0.14) and (-0.44±0.15)μm in SMILE group, and (-0.20±0.10), (-0.71±0.23) and (-0.75±0.20)μm in SPT-TransPRK group respectively, showing statistically significant differences ( Fgroup=31.037, P<0.001; Ftime=48.005, P<0.001). The postoperative total corneal HOA and spherical aberration were increased in both groups compared with before surgery, with statistically significant differences (all at P<0.05). The 1- and 3-month postoperative total corneal HOA and spherical aberrations were smaller in SMILE group than in SPT-TransPRK group, and the differences were statistically significant (all at P<0.05). The 1- and 3-month postoperative coma were increased in both groups compared with before surgery, showing statistically significant differences (all at P<0.05). In SMILE group, 1-month postoperative OSI was higher and 1-month postoperative MTF cut-off, SR, and VA9 were lower than those before surgery, and 3-month postoperative OSI was higher and 3-month postoperative SR and VA9 were lower than those before surgery, showing statistically significant differences (all at P<0.05). In SPT-TransPRK group, 1-month postoperative OSI was higher and 1-month postoperative MTF cut-off, SR, VA100, VA20, and VA9 were lower than those before surgery, showing statistically significant differences (all at P<0.05). There was no significant difference in OSI, MTF cut-off, SR, VA100, VA20, and VA9 between 3 months postoperatively and before surgery in the SPT-TransPRK group (all at P>0.05). There was no significant difference in coma, OSI, MTF cut-off, SR, VA100, VA20, and VA9 between two groups (all at P>0.05). Conclusions:Both SMILE and SPT-TransPRK are effective methods for correcting myopia and they have comparable visual quality.Compared with SPT-TransPRK, corneal total HOA and spherical aberration are smaller after SMILE.