The impact of 3D visual training combined with physical exercise intervention on the visual health of myopic adolescents

Quantitative analysis of peripheral retinal defocus checked by multispectral refraction topography in myopia among youth.

To assess the visual quality, both subjective and objective, of cataract patients with varying axial lengths (AL) after PanOptix trifocal intraocular lens (IOL) implantation and investigated the lens tilt and its correlation with visual outcomes. From July 2020 to June 2022, 70 patients (140 eyes) diagnosed with age-related cataracts and undergoing PanOptix implantation at Chongqing Eye and Vision Care Hospital, Aier Eye Hospital Group, were included. Patients were assigned to either the observation group (35 cases, 70 eyes with PanOptix trifocal IOL) or the control group (35 cases, 70 eyes with bifocal IOL). Patients were further subdivided based on AL into AL < 24 mm (observation group: 23 eyes; control group: 26 eyes) and AL ≥ 24 mm (observation group: 47 eyes; control group: 44 eyes). Postoperative follow-up lasted three months. Visual acuity (distant, intermediate, near), objective visual quality (Strehl ratio: SR, total eye modulation transfer function (MTF)), and visual aberrations were measured preoperatively and at 3 months post-operation. Postoperatively, all groups saw significant improvements in uncorrected distance visual acuity (UCDVA), uncorrected intermediate visual acuity (UCIVA), and uncorrected near visual acuity (UCNVA) compared to preoperative values (T0) (all P < 0.05). Notably, UCIVA was significantly better in the observation group than in the control group (P < 0.05). At three months (T1), reductions in total high-order aberration (tHOA), internal high-order aberration (iHOA), coma, and trefoil aberrations were observed in both groups compared to baseline, with more significant decreases in the observation group (all P < 0.05). Both SR and MTF cutoff showed marked improvement from T0 to T1, with the observation group experiencing greater enhancements (both P < 0.05). The defocus curve of the observation group showed a gentle slope between +0.5 D and -3.0 D, maintaining superior visual acuity compared to the control group (P < 0.05). Subjective visual quality scores at T1 were significantly higher than at T0 for both groups (P < 0.05), with patients in the observation group scoring higher than those in the control group across all AL categories (P < 0.05). Spearman correlation analysis indicated that the tilt after PanOptix trifocal IOL implantation was associated with tHOA (r = 0.273, P = 0.022), iHOA (r = 0.433, P < 0.001), Trefoil (r = 0.360, P = 0.002) and coma (r = 0.688, P < 0.001). PanOptix trifocal IOL implantation in cataract patients across different AL significantly enhances visual quality compared to bifocal IOLs, suggesting a strong case for its clinical adoption.

Objective To observe the clinical effects and safety of orthokeratology(OK) lens in the treatment of mild and moderate myopia, and to evaluate the effects on the myopia control. Methods The study included a total of 166 eyes in 83 myopia children who were treated in Jiaxing Traditional Chinese Medicine Hospital Affiliated to Zhejiang Chinese Medical University from January 2014 to December 2014.They were randomly divided into two groups according to the digital table, 43 cases(86 eyes) in the observation group underwent standard OK lens, and the other 40 cases(80 eyes) in the control group were given common spectacles.The patients were followed up for two years.The uncorrected visual acuity, corneal curvature and ocular surface in the, observation group were examined, and diopter, axial length were examined in the two groups. Results The visual acuity of the observation group improved significantly at 1 day, trended to be stable at 1 week, and then was basically stable within 1 year, but decreased at 2 years.After 3 months, the mean corneal curvature[(41.93±1.12)D]was significantly lower than before orthokeratology[(43.56±1.44)D], and the difference was statistically significant(t=11.539, P<0.05). However, the effect didn’t persist without continued OK lens wear 1 month later.Compared with the control group, the growth of the diopter and axial length in the observation group were significantly slower(t=16.784, P<0.05; t=5.623, P<0.05). At the initial wearing, 34% of the observation group occurred corneal epithelial injury, but they all recovered by stop wearing and appropriate medication.With the prolong of wear time, the proportion of injury reduced. Conclusion Uncorrected visual acuity of mild and moderate myopia children wearing OK lens can significantly improve at 1 day, then is basically stable after 1 year, but declines within 2 years, which indicates the need for timely replacement of the lens.Long-term wearing is effective and safe to control the development of myopia. Key words: Epikeratophakia; Myopia; Visual acuity; Corneal curvature

The aim of this study is to determine and compare biometric and refractive characteristics of thalassemia major patients and normal individuals. In this cross-sectional study, 54 thalassemia major patients were selected randomly as case group, and 54 age- and sex-matched healthy subjects were regarded as control group. Refractive errors, corneal curvature and ocular components were measured by autokeratorefractometery and A-scan ultrasonography, respectively. Mean spherical equivalent was -0.0093±0.86D in thalassemia patients and -0.22±1.33D in the normal group. The prevalence of myopia, Hyperopia, and emmetropia among thalassemia patients was 16.7, 19.4, and 63.9%, respectively. While in the control group, 26.9% were myopic, 25% were hyperopic, and 48.1% were emmetropic. The prevalence of astigmatism in case group was 22.2%, which was not significantly different from that in control group, (27.8%, p=0.346). Mean axial length in thalassemia patients was 22.89±0.70 which was significantly lower than that in normal group (23.37±0.91, p=0.000). The flattest meridian of the cornea (R1) was significantly steeper in thalassemia patients (7.77±0.24) in comparison to normal individuals (7.85±0.28). Although thalassemic patients had significantly smaller axial length and vitreous chamber depth in comparison to normal group, which could be due to their abnormal physical growth, there was no significant difference between the mean of spherical equivalent among two groups. This can be due to their steeper corneal curvature that overcomes the refractive disadvantage of their shorter axial length.

ObjectivesTo describe and compare the prevalence of refractive error and its associated ocular biometric parameters in a large multi-racial sample of schoolchildren from Xinjiang.MethodsA total of 67,102 school children of five ethnicity groups aged 6–23 years from 46 schools in Xinjiang participated in this study. The children underwent a comprehensive eye examination for vision screening, including uncorrected visual acuity and standardized refraction. Refractive error was determined by autorefractors and subjective refraction. Refraction was recorded in spherical equivalent (SE). The age- and sex- adjusted prevalence of myopia (SE ≤ −0.5 D), low myopia (−6 D < SE ≤ −0.5 D), high myopia (SE ≤ −6.0 D), astigmatism (cylinder < −0.5 D), and anisometropia (difference in SE between two eyes of 1.0 D) in the five ethnic groups were calculated. Ocular biometric parameters including axial length (AL) and corneal radius of curvature (CR) were measured by AL-scan optical biometer.ResultsThe age- and sex- adjusted prevalence of myopia in the Han, Hui, Uyghur, Kyrgyz and Kazakh were 65.8% (95% confidence interval [CI] 65.4, 66.3); 59.1% (95% CI 57.8, 60.4); 30.1% (95% CI 29.2, 30.9); 30.2 (95% CI 28.9, 31.4); and 30.0% (95% CI 27.6, 32.3), respectively. The Han and Hui children also had longer ALs (Han, 23.8; Hui, 23.6, Uyghur, 23.1; Kyrgyz, 23.1; Kazakh, 23.3 mm) and larger AL/CR (Han, 3.04; Hui, 3.00; Uyghur, 2.95; Kyrgyz, 2.96; Kazakh, 2.97) values than the other three minorities (P < 0.01). Overall, girls had shorter ALs, steeper corneas, and smaller AL/CR values than boys (P < 0.01).ConclusionsSignificant ethnic difference in the prevalence of myopia was observed in this study on school-aged children in Xinjiang (Han > Hui > Kyrgyz > Uyghur > Kazakh). This study among different ethnic groups in a multiethnic population is valuable for enriching the ethnical information resources for refractive errors and ocular biometry parameters, as well as facilitating further research on myopia-related diseases and risks.

Objective: We compared the clinical outcomes of toric intraocular lens (IOL) implantation for treating age-related cataracts associated with either total corneal astigmatism or anterior corneal astigmatism. Methods: In this retrospective clinical control study, 141 patients with age-related cataracts and corneal astigmatism were recruited and divided into an observation group (75 patients, 90 eyes) and a control group (66 patients, 81 eyes). The observation group was established based on a total corneal astigmatism of 3 mm in diameter, and the control group was established based on an anterior corneal astigmatism of 3 mm in diameter. The uncorrected distance vision acuity (UCDVA), residual astigmatism (RA), and IOL rotation three months after the surgery were recorded. The visual acuity was measured as the logarithm of the minimum angle of resolution (LogMAR). An astigmatism-biased subgroup and an astigmatism-unbiased subgroup were established within the observation and control groups according to whether the difference of the cylindrical lens was larger than 0.5 diopter (D) or the difference of the axial view was larger than 10° between the total and anterior corneal astigmatism. The means ± standard deviations ( ±s ) of vision acuity, spherical equivalent, axial length, corneal astigmatism, and RA were determined. Comparisons between groups were based on the independent samples t-tests. Results: Three months after the surgery, the UCDVA values of the control and observation groups were 0.10 ± 0.13 and 0.06 ± 0.12 (LogMAR), respectively. The mean IOL rotations were 5.6° ± 3.6° and 5.8° ± 3.8°, respectively. There were no significant differences between the groups (UCDVA: t=1.35, P=0.18; IOL rotations: t=0.66, P=0.51). The mean RA values for the control and observation groups were 0.63 ± 0.29 D and 0.52±0.22 D, respectively (t=2.07, P=0.04). The mean UCDVA of the astigmatism-biased subgroup was significantly better, and the mean RA was significantly lower than the corresponding values in the control group (UCDVA: t=2.54, P=0.02; RA: t=3.40, P<0.001). The mean UCDVA, RA, and IOL rotations in the astigmatism-unbiased subgroup and the control group were not significantly different. Conclusions: The clinical outcomes of toric IOL implantation for treating age-related cataracts are better for patients with total corneal astigmatism than those with anterior corneal astigmatism. Key words: cataract; intraocular lense; total corneal astigmatism

To compare the visual refractive outcome and complication of laser in situ keratomileusis (LASIK) carried out with a Carl Zeiss-Meditec MEL-70 Excimer laser and a MEL-80 laser for treatment of high myopia. Journal records of 680 consecutive eyes that underwent LASIK with a Schwind Supratome microkeratome and a MEL-70 Excimer laser (Group A), or a Moria M2 microkeratome and a MEL-80 Excimer laser (Group B) were reviewed. Manifest refraction, uncorrected and best spectacle-corrected visual acuity (BSCVA), corneal topography and central corneal thickness (CCT) were recorded before and 3 months after treatment. Pre- and postoperative complications, visual and refractive outcome and frequency of retreatments were registered. Mean preoperative spherical equivalent refraction was -8.52 dioptres (-5.50- -18 dioptres), and the mean attempted laser correction was -8.02 dioptres (-5.50- -11 dioptres). Three months after LASIK, the average treatment error (difference between achieved and attempted correction) was 1.20 (SD=1.19) dioptres of under correction in Group A and 0.52 (SD=1.00) dioptres in Group B. Four eyes lost more than two lines of BSCVA (0.6%). In 110 eyes (16%), a re-LASIK procedure was performed to reduce remaining myopia after the primary procedure. Laser in situ keratomileusis treatment for high myopia can effectively reduce high degrees of myopia. Under correction was observed in both treatment groups but Group B has a slightly better predictability. Significant loss of BSCVA occurs infrequently after LASIK for even considerable grades of myopia (0.6% in each group).

Objective: To explore the characteristics of orthokeratology lenses designed for small correction zones and their effectiveness and safety in long-term prevention and control of myopia in children and adolescents. Methods: It was a prospective cohort study that included myopic children and adolescents who received corneal reshaping treatment at the Qingdao Eye Hospital of Shandong First Medical University between January 2019 and May 2020. The patients were randomly divided into two groups using computer-generated randomization, and were fitted with corneal reshaping lenses with small treatment zones and conventional designs, respectively. The uncorrected visual acuity, best-corrected visual acuity, refractive error, and axial length were measured before and after 6, 12, and 18 months of wearing the lenses. Corneal topography with the Pentacam was also performed, and the area and diameter of the corneal treatment zone were calculated using the Matlab software. Results: A total of 60 myopic patients (60 eyes) were enrolled, including 29 males and 31 females, with an age of (10.40±1.01) years and a spherical equivalent of (-2.88±0.42) D. There were 30 cases in the small correction zone group and 30 cases in the conventional group. There was no significant difference in uncorrected visual acuity and spherical equivalent between the two groups at each time point after treatment. The axial growth in the conventional group was (0.16±0.09) mm at 6 months after treatment, (0.28±0.17) mm at 12 months, and (0.37±0.20) mm at 18 months, whereas in the small treatment zone group it was (0.06±0.05) mm, (0.12±0.10) mm, and (0.18±0.14) mm, respectively. The myopia progression rate in the small treatment zone group was only 37.50%, 42.86%, and 48.64% of the conventional group at 6, 12, and 18 months, respectively. Corneal topography showed that the treatment area in the conventional group was (6.98±0.89) mm², while in the small treatment zone group it decreased by 23.2% [(5.36±0.73) mm²] (P<0.05). Correlation analysis revealed that the axial increase after 18 months of lens wearing was negatively correlated with the age before lens wearing (P<0.05), positively correlated with the corneal surface treatment zone size (P<0.05), and not correlated with the pupil diameter and spherical equivalent (all P>0.05). After the shaping treatment, the rate of adverse reaction, which was mild, in both groups was 10%, and the symptoms disappeared. Conclusion: Orthokeratology lenses with smaller treatment zones can significantly reduce the rate of axial length growth in children and adolescents compared to lenses with conventional treatment zones, without compromising treatment safety.

To compare uncorrected visual acuity and refractive error in patients undergoing photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) between 1 week and 6 months after surgery. All eyes underwent PRK or LASIK with the VisX StarS2 excimer laser. We retrospectively analyzed data from 77 random eyes of 77 patients in the PRK group and 76 eyes of 76 patients in the LASIK group. All eyes had a low myopic refractive error (spherical equivalent range, -0.88 diopters (D) to -5.13 D; mean PRK. -2.8 +/- 0.20 D: LASIK, -2.5 +/- 0.22 D). Uncorrected visual acuity and manifest refractive error were evaluated 1 week, 1 month, and 6 months after surgery. Each eye undergoing PRK was paired with an eye undergoing LASIK for a similar level of spherical equivalent. Mean uncorrected visual acuity after 1 week was 0.85 +/- 0.06 (20/25, logMAR 0.12 +/- 0.04) for the PRK group and 1.01 +/- 0.06 (20/20, logMAR 0.01 +/- 0.03) for the LASIK group (p < 0.001). Mean spherical equivalent after 1 week was 0.23 +/- 0.12 D for the PRK group and -0.02 +/- 0.07 D for the LASIK group (p = 0.02). Mean uncorrected visual acuity after 1 month was 1.03 +/- 0.05 (20/20, logMAR 0.02 +/- 0.03) for the PRK group and 1.05 +/- 0.05 (20/20. -0.02 +/- 0.03) for the LASIK group (p = 0.16). Mean spherical equivalent after I month was 0.19 +/- 0.10 D for the PRK group and -0.02 +/- 0.09 D for the LASIK group. This difference was statistically significant (p = 0.02), but was unlikely to be clinically significant. Mean uncorrected visual acuity after 6 months was 1.05 +/- 0.06 (20/20, logMAR -0.01 +/- 0.03) for the PRK group and 1.06 +/- 0.05 (20/20, logMAR -0.14 +/- 0.03) for the LASIK group (p = 0.41). Mean spherical equivalent after 6 months was 0.02 +/- 0.08 D for the PRK group and 0.00 +/- 0.08 D for the LASIK group (p = 0.35). Uncorrected visual acuity 1 week after surgery is significantly better in eyes undergoing LASIK than in eyes undergoing PRK. Both procedures provide functional vision by 1 week after surgery. The difference does not relate to refractive error, which was similar between the two groups, but to differences in healing of the epithelium. By 1 month after surgery, there is no difference in mean uncorrected visual acuity between eyes that undergo PRK or LASIK for low myopia.

Objective: To study the prevalence and risk factors of myopia in the initial stage among third-grade students in public primary schools, and to provide protective suggestions for the prevention and control of myopia among adolescents. Methods: A cross-sectional study was used. From November 2017 to February 2018, a total of 1 004 third-grade students in Gongshu District of Hangzhou City were surveyed. Myopia questionnaires were used and eyesight-related parameters were obtained using cycloplegic refraction and biometry. Detailed questions on date-of-birth, outdoor activities, indoor activity, and parental refractive errors were asked in face-to-face interviews using a standard questionnaire. Cycloplegic refraction was performed on each research subject and a spherical equivalent (SE) of≤-0.5 D was designated as the myopia group and an SE>-0.5 D was designated as the non-myopia group. A rank sum test and Chi square were applied for parameters between the myopia and non-myopia groups. A binary logistic regression analysis was performed with myopia/non-myopia as dependent variables and all parameters as independent variables. Results: The prevalence of myopia (SE≤-0.5 D) was 32.3% among the 1 004 investigated subjects, 29.2% for male students and 35.4% for female students, implying a significant difference (χ2=4.43, P=0.035). Myopia prevalence for subjects born in the second quarter was significantly higher than those born in the first (χ2=4.30, P=0.041) and the fourth quarters (χ2=12.06, P<0.001). Logistic regression analysis demonstrated that the risk factors for the prevalence of myopia include degree of myopia on the paternal side (OR=1.509, P<0.001), degree of myopia on the maternal side (OR=1.360, P<0.001), female gender (binary logistic regression, OR=1.329, P=0.049), time spent on nearwork after school (OR=1.467, P=0.034), time spent on nearwork during holidays (OR=1.352, P<0.001), time spent on middle-distance work after school (OR=1.626, P=0.045) and time spent on middle-distance work during holidays (OR=1.860, P<0.001), while time spent outdoors after school (OR=0.618, P<0.001) and time spent outdoors during holidays (OR=0.823, P=0.004) act as protective factors. Conclusion: For the initial stage of myopia, our data analysis on third-grade students in the Gongshu District of Hangzhou shows that less outdoor activity, more near-distance and middle-distance work, parental history of myopia and female gender were associated with a greater risk for myopia. More outdoor activities may help to reduce the high prevalence of myopia. In addition to school days, holidays deserve more attention. Key words: prevalence of myopia; primary students; associated factors

BackgroundThe aim of this study was to investigate the prevalence of myopia in key (university‐oriented) and non‐key elementary schools in China using a traditional and a new criterion for myopia diagnosis in an epidemiological study.MethodsThis school‐based, cross‐sectional study examined students from four key schools and seven non‐key schools. Non‐cycloplegic autorefraction and visual acuity (VA) were performed on each student. Myopia was defined as a spherical equivalent (SE) refractive error not better than −1.00 D. A questionnaire was also administered.ResultsOf the 13,220 students examined, 6,546 (49.5 per cent) had myopia using the criterion of SE not better than −1.00-D. However, 2,246 (34.3 per cent) of these myopes had VA ≥ 0 logMAR in both eyes, indicating they were not functioning as myopes. Thus, a second myopia criterion was adopted: SE refractive error not better than −1.00 D + uncorrected VA ≥ 0 logMAR in at least one eye. By this definition, only 32.5 per cent of the overall sample had myopia. Students in key schools had a higher prevalence of myopia than those in non‐key schools (53.8 per cent versus 44.7 per cent) by the initial criterion. By the new criterion, the prevalence of myopia was 41.2 per cent versus 22.7 per cent. Myopia was equal in grade 1 of both school types, but accelerated faster in key schools, where there was a much higher prevalence of myopia by fourth grade, and continued up to 79.2 per cent prevalence by sixth grade based on SE refractive error not better than −1.00 D.ConclusionStudents in more competitive university‐oriented elementary schools developed myopia much faster than those in regular schools, although they started with the same level of myopia. Since one‐third of the ‘myopes’ had VA ≥ 0 logMAR in both eyes, they would not be prescribed a correction, or be clinically treated as myopes. A new criterion of SE refractive error not better than −1.00 D + uncorrected VA ≥ 0 logMAR in at least one eye was tested. This criterion is more clinically appropriate and could be used in future epidemiological studies.

Objective To compare and analyze the higher-order aberrations (HOA),contrast sensitivity (CS) and CS under the glare after FEMTO LDV femtosecond laser flap and mechanical microkeratome Hansatome flap in laser in situ keratomileusis (LASIK).Methods This was a prospective clinical controlled study.Ninety-two eyes of 46 patients were treated with FEMTO LDV as the observation group,and 104 eyes of 52 patients were treated with Hansatome as the control group.Wavefront-guided LASIK (Zyoptix) was performed on each of these eyes after the flap preparation.HOA,CS and CS under the glare were evaluated before surgery and 1 week,1 month,3 months after treatment.Data were analyzed using chi-square test,ANOVA,independent t test.Results At 1 week after the surgery,59/92(64.1％) patients in the observation group had uncorrected visual acuity (UCVA) levels reaching or surpassing the preoperative best corrected visual acuity (BCVA),while in the control group,this rate was 76/104(73.1％).At 1 month after the surgery,the rate of UCVA≥preoperative BCVA was 82/92 (89.1％) in observation group and 96/104 (92.3％) in control group.At 3 months after the surgery,the rate of UCVA≥preoperative BCVA was 86/92(93.5％) in observation group and 96/104(92.3％) in control group.The two groups were not significantly different after the surgery (x2=1.423,1.112,0.183,P＞0.05).The refraction was +0.49±0.24 D in the observation group and +0.35±0.32 D in the control group at 1 week after surgery,while at 3 months,it was +0.10±0.18 D in the observation group and-0.14±0.22 D in the control group.The differences between the 2 groups were insignificant (t=0.566,1.178,P＞0.05).Higher-order aberration.At 1 week and 3 months,the HOA and coma in the observation group were all lower than in the control group (t1w=-2.422,-2.295,t3m=-1.957,-1.926,P＜0.05).There were no difference in spherical aberration and trefoil between the 2 groups (t1 w=-1.395,-0.779,t3m=-1.205,-0.922,P＞0.05).The 2 groups photopic CS was not significantly different after the surgery.The observation group mesopic CS decreased to the lowest level at 1 week postoperation,and returned to preoperative level at 1 month after operation.At 1 month and 3 months,the CS were higher than preoperation at 3.0,18.0 c/d (F=3.602,3.216,P＜0.05).At 1 week after surgery,the mesopie CS of the observation group was better than the control group at 6.0 c/d (t=2.326,P＜0.05).The 2 groups mesopic CS was not significantly different at 1 month and 3 months after operation.At 1 week after surgery,the photopic CS under the glare stimulus of the observation group was significantly higher than the control group at 3.0,12.0 c/d (t=2.173,2.327,P＜0.05).At 3 months,the medium to low spatial frequencies (1.5,3.0,6.0 c/d) the mesopic CS of observation group was higher than the control group (t=2.428,2.416,2.507,P＜0.05).Conclusion Patients undergoing femtosecond laser-assisted LASIK have better quality of vision after surgery than hansatome patients. Key words: Femtosecond laser; Keratomileusis,laser in situ; Aberration; Contrast sensitivity ; Glare

Objective To investigate the prevalence of refractive errors among school children in Suining City, Sichuan Province, and to provide a scientific basis for prevention and control of myopia. Methods This was a school-based cross-sectional study. Children aged 6-15 years were selected from kindergartens, primary schools, and middle schools in the urban setting of Suining City. The children underwent ocular examination including measurement of uncorrected visual acuity (UCVA), visual acuity when wearing glasses, and noncycloplegic autorefractometry. Results Of the 1200 eligible students, 1138 children (94.8%), 553 of them girls (47.4%), participated. The mean age was 10.64 ± 2.89 years. The prevalence of myopia, hyperopia, astigmatism, and emmetropia was 59.1% (95% confidence interval (CI): 57.6, 60.5), 5.0% (95% CI: 4.7, 6.1), 38.4% (95% CI: 55.5, 58.5), and 25% (95% CI: 23.7, 26.2), respectively. In univariate analysis, the prevalence of myopia was correlated with age, female gender, and learning stage. The prevalence of hyperopia and astigmatism was correlated with age and learning stage. The prevalence of mild myopia, moderate myopia, and high myopia in the 1138 students was 17.7%, 41.4%, and 3.3%, respectively. The prevalence of mild, moderate, and high myopia all increased with age and learning stage. The prevalence of myopia differed by gender. The mean spherical equivalents of the right and left eyes were −1.40 ± 1.99 diopters (D) and −1.29 ± 1.93 D, respectively, and the median values were -0.75 D and -0.6 D, respectively. The mean spherical equivalent increased with age, learning stage, and female gender. Conclusions The most common type of refractive error was myopia which was associated with higher age, female gender, and higher learning stage. This study provides new data and recommendations for myopia-control in school-aged children in Sichuan province.

Efficacy in Myopia Control: Does Race Matter?

Purpose: To evaluate changes in refractive errors and quantify optometric values in 4th graders at an urban elementary school in Korea. Methods: A total of 188 school children (376 eyes) were assessed in a population-based, cross-sectional and longitudinal follow-up study between March and December 2003. Uncorrected visual acuity, best corrected visual acuity, corneal refractive power measured with auto keratometer (KR-8100, TopconⓇ Inc., Japan), axial length measured with A-scan ultrasound biometry (A/B-scan system 835, HumphreyⓇ Inc., Dublin, CA), and cycloplegic refraction were evaluated on March and December, respectively. Results: Mean visual acuity decreased from -0.15±0.29 LogMAR to -0.20±0.35 LogMAR and mean spherical equivalent (SE) showed myopic progression from -0.65±1.57 diopter (D) to -0.88±1.75D. The prevalence rate of myopia (≤-0.50D SE) was increased from 44.1% to 50.3%, while that of hyperopia (≥+1.00D SE) was decreased from 8.0% to 5.8%. Mean corneal refractive power changed from 43.21±1.29D to 43.35±1.31D, and mean axial length changed from 23.38±0.88 mm to 23.60±0.92 mm, respectively. Conclusions: We assessed the changes of refractive errors and quantified the optometric values in a population-based, longitudinal follow-up study. The results showed that the prevalence of myopia and the mean axial length increased during our study in urban elementary 4th graders in Korea.