ObjectiveTo compare the changes of corneal astigmatism after long-term spherical and toric orthokeratology wearing, and to investigate the effects of different orthokeratology design on corneal astigmatism.MethodsThe medical records of myopic adolescent patients who have been prescribed spherical and toric orthokeratology in the contact lens clinic of West China Hospital, Sichuan University between January 2019 and December 2021 were analyzed retrospectively.The differences of corneal astigmatism changes after wearing spherical and toric orthokeratology for a long time and one month discontinuation were compared. The influencing factors of corneal astigmatism changes were analyzed. ResultsA total of 156 patients were included. There were 76 cases (76 eyes) in spherical orthokeratology group and 80 cases (80 eyes) in toric orthokeratology group. There was no significant difference between the two groups in age, gender, baseline myopia diopter and total lens wearing time (P>0.05). There were statistically significant differences between the spherical orthokeratology group and the toric orthokeratology group in the baseline corneal flat K value [42.1 (41.3, 43.3) vs. 43.1 (42.0, 44.1) D], baseline corneal steep K value [(43.4±1.3) vs. (44.6±1.5) D], baseline corneal astigmatism [(1.1±0.5) vs. (1.6±0.6) D], and baseline total eye astigmatism [?0.6 (?1.2, 0.0) vs. ?1.4 (?1.8, ?1.0) D] before wearing the orthokeratology (P<0.05). Compared with the baseline value, 1 month after the two groups stopped wearing the orthokeratology, the corneal flat K values became flatter [spherical orthokeratology group: 42.09 (41.28, 43.34) vs. 41.73 (40.98, 43.16) D, toric orthokeratology group: 43.09 (41.95, 44.10) vs. 42.61 (41.52, 43.56) D; P<0.05], the changes of corneal steep K values were not statistically significant (P>0.05), but the corneal astigmatism values increased [spherical orthokeratology group: (1.05±0.49) vs. (1.37±0.56) D, toric orthokeratology group: (1.62±0.57) vs. (1.99±0.63) D; P<0.05]. There was no significant difference in the changes of corneal flat K value, corneal steep K value and corneal astigmatism between the two groups (P>0.05). Multivariate analysis showed that age (P=0.011) and the total duration of orthokeratology wearing (P=0.004) were the main factors affecting the changes of corneal astigmatism. ConclusionAfter 1 month of non-wearing, the flat K value of the cornea becomes flat, the steep K value remains unchanged, and the corneal astigmatism increases. There is no difference in the effect of the spherical and toric orthokeratology on corneal astigmatism. The change of corneal astigmatism is related to the patient’s age and the total duration of wearing the orthokeratology. The younger the age, the longer the duration of orthokeratology wearing, the more significant the increase of corneal astigmatism after stopping wearing the orthokeratology.
Objective To explore the application effect of virtual reality (VR) technology in low vision teaching for optometry students. Methods Undergraduate students majoring in optometry at West China School of Medicine of Sichuan University were selected as the research subjects. The students enrolled in 2020 adopted the traditional lecture-based learning (LBL) teaching mode (LBL teaching group), while the students enrolled in 2021 adopted the VR teaching mode (VR teaching group). Both groups of students studied the content of the same chapter on low vision, completed in-class tests after learning, and completed a questionnaire survey. Results There were 28 students in the VR teaching group and 30 students in the LBL teaching group. There was no statistically significant difference in age or gender composition between the two groups of students (P>0.05). The in-class test scores of students in the VR teaching group were higher than those in the LBL teaching group (86.43±6.10 vs. 78.10±7.69, P<0.05). Except for “subjective discomfort with this teaching mode”, the differences in other evaluation results between the two groups were statistically significant (P<0.05). VR teaching group students generally believed that applying VR technology to low vision teaching helped understand the visual experience and daily life status of low vision patients, improved learning efficiency and hands-on ability, reduced learning burden, and hoped to use this teaching mode routinely in other subject teaching. All students in the VR teaching group believed that this teaching mode was interesting, highly innovative, and enhanced teacher-student interaction.Conclusions Applying VR technology to low vision teaching can enable students to personally experience the impact of various diseases on patients’ visual function and daily life. This teaching method not only optimizes and improves teaching effectiveness, but also has a high acceptance rate among students, which is worth further promoting in future optometry teaching.
