ABSTRACT
PURPOSE: Autostereoscopic displays have become increasingly common, but their impact on ocular dimensions remains unknown. We sought to identify changes in the crystalline lens dimensions induced by autostereoscopic three-dimensional (3D) viewing. METHODS: Forty young adults (age: 22.6 ± 2.0 years, male/female: 15/25) were consecutively enrolled and randomly divided into two groups (3D and two-dimensional [2D] viewing groups) to watch a 30-min movie clip displayed in 3D or 2D mode on a tablet computer. The lens thickness (LT), diameter, curvature, decentration and tilt were measured with anterior segment optical coherence tomography under both non-accommodating (static) and accommodating conditions. RESULTS: In the static condition, the LT decreased by 0.03 ± 0.03 mm (p < 0.001) and the anterior radius of curvature (ARC) increased by 0.49 ± 0.59 mm (p = 0.001) post-3D viewing. In contrast, following 2D viewing, the ARC decreased by 0.23 ± 0.25 mm (p = 0.001). Additionally, the increase in the steep ARC post-3D viewing was greater in high-myopic eyes than low to moderate myopic eyes (p = 0.04). When comparing the accommodative with the static (non-accommodative) condition, for 3D viewing the lens decentration decreased (-0.03 ± 0.05 mm, p = 0.02); while for 2D viewing, the posterior curvature radius (-0.14 ± 0.20 mm, p = 0.006) and diameter (-0.13 ± 0.20 mm, p = 0.01) decreased. CONCLUSIONS: Viewing with the autostereoscopic 3D tablet could temporally decrease the thickness and curvature of the lens under non-accommodating conditions. However, its long-term effect requires further exploration.
ABSTRACT
PURPOSE: To compare the long-term refractive outcomes and visual quality after KLEx and EVO-ICL implantation for high myopia. SETTING: Eye & ENT Hospital of Fudan University, Shanghai, China. DESIGN: A retrospective study. METHODS: This study included 31 KLEx-treated patients (31 eyes, spherical equivalent: -7.62D ± 1.22) and 32 ICL-treated patients (32 eyes, spherical equivalent: -8.22D ± 1.18). Refractive outcomes and objective visual quality were examined. Subjective visual quality was evaluated by a customized questionnaire. Patients' satisfaction was graded. RESULTS: Five-year postoperatively, the efficacy (KLEx: 0.96 ± 0.20; ICL: 1.03 ± 0.20; P = 0.164) and safety indices (KLEx:1.12 ± 0.20; ICL: 1.21 ± 0.19; P = 0.067) were comparable. Statistically higher proportions of ICL-treated eyes achieved a postoperative UDVA of 20/20 or better (P = 0.035). Refractive predictability was similar between the two groups (P = 0.947), whereas more KLEx-treated eyes had myopic refractive errors (P < 0.001). Total coma was significantly higher after KLEx (P = 0.020), and greater total trefoil was observed after ICL implantation (P = 0.006). Haloes were the primary visual disturbance in both groups (KLEx: 64.5%; ICL: 93.8%). The incidences of haloes (P < 0.001), glare (P = 0.004), and starbursts (P = 0.043) were notably higher after ICL implantation. The patient's satisfaction scores were similar (KLEx: 9.10 ± 1.27; ICL: 9.10 ± 1.27; P = 0.894). CONCLUSIONS: For high myopia, EVO-ICL yielded better long-term refractive outcomes than KLEx. Haloes were the chief complaint in both groups, with a significantly higher incidence after ICL implantation.
ABSTRACT
Small incision lenticule extraction (SMILE) is a "flapless" keratorefractive surgery with excellent safety, efficacy, stability, and predictability for myopia correction. A recent global multicenter study also reported good refractive outcomes for hyperopic SMILE. SMILE has shown advantages including improved biomechanical strength, fewer dry eye symptoms, less corneal denervation, and fewer surgery-induced higher-order aberrations over laser in situ keratomileusis (LASIK). However, night vision complaints, including glare, halos, and starbursts, could still occur after SMILE. These symptoms have been proven to be closely related to the effective optical zone (EOZ), which is defined as the achieved area of corneal ablation. A larger postoperative EOZ may indicate better visual quality, making EOZ an important safety parameter for keratorefractive surgeries. As SMILE has gained wider application globally, the EOZ following SMILE has also been increasingly studied in the field of refractive surgery. This review provides an update on topics related to the EOZ after SMILE, including its measurement and influencing factors, aiming to benefit the personalization of the surgical algorithm and ultimately improve the visual quality after the SMILE procedure.
