Combined 0.01% atropine with orthokeratology in childhood myopia control (AOK) study: A 2-year randomized clinical trial.

BACKGROUND: To investigate whether combining 0.01% atropine with orthokeratology (AOK) has a better effect in retarding axial elongation, compared with orthokeratology alone (OK) over two years. METHODS: A total of 96 Chinese children aged six to < 11 years with myopia (1.00 - 4.00 D, inclusive) were randomized into either the AOK or OK group in a 1:1 ratio. Axial length (the primary outcome), and secondary outcomes (e.g. pupil size and choroidal thickness) were measured at 1-month and at 6-monthly intervals after commencement of treatment. RESULTS: Both intention-to-treat and per-protocol analyses showed significantly slower axial elongation in the AOK group than OK group over two years (P = 0.008, P < 0.001, respectively). AOK subjects had statistically slower axial elongation (adjusted mean [standard error], 0.17 [0.03] mm vs 0.34 [0.03] mm, P < 0.001), larger increase in mesopic (0.70 [0.09] mm vs 0.31 [0.09] mm, P = 0.003) and photopic pupil size (0.78 [0.07] mm vs 0.23 [0.07] mm, P < 0.001), and greater thickening of the choroid (22.6 [3.5] µm vs -9.0 [3.5] µm, P < 0.001) than OK subjects over two years. Except for a higher incidence of photophobia in the AOK group (P = 0.006), there were no differences in the incidence of any other symptom or adverse events between the two groups. Slower axial elongation was associated with a larger increase in the photopic pupil size and a greater thickening in the choroid in the AOK group. CONCLUSIONS: Slower axial elongation following 2-year AOK treatment may result from increased pupil dilation and a thickening in the choroid observed in the AOK group.

Repeatability of pupil size measurements with NIDEK OPD-Scan III in myopic children.

OBJECTIVE: To investigate the repeatability of pupil size measurements, determined from the NIDEK OPD-Scan III, of myopic eyes in children wearing single-vision spectacles (SVS), undergoing orthokeratology (OK) and receiving combined treatment of 0.01% atropine and orthokeratology (AOK). METHODS: A single examiner took two sets of mesopic pupil size measurements from the right eyes of 80 children (SVS:16, OK: 34, AOK: 30) (mesopic 1 and mesopic 2) and two sets of photopic (photopic 1 and photopic 2) pupil size measurements (internal light source) using the NIDEK OPD-Scan III. Each set was taken at a single visit, 15 min apart. Subjects in the OK and AOK groups had undergone treatment for at least 6 months, and the SVS subjects had no previous myopia treatment other than wearing spectacles. Repeatability of measurements was analysed using intraclass correlation coefficient (ICC), Bland-Altman (BA) plot, and coefficient of repeatability (CoR). RESULTS: Mesopic 1 and 2 values were not significantly different among the three groups (p = 0.56, 0.77), hence the data were pooled for each set of measurements (mean [±S.D.] values were 7.09 ± 0.61 and 7.12 ± 0.61 mm, respectively) for further analyses. ICC for repeated mesopic pupil size measurements was 0.98 (95% CI, 0.98-0.99). No significant correlation was found between the means of the mesopic 1 and 2 measurements and their differences (Pearson's r = -0.02, p = 0.83). A BA plot also demonstrated narrow 95% limits of agreement, with a CoR of 0.28 mm. Mean photopic 1 and 2 measurements for the AOK group (3.74 ± 0.46; 3.73 ± 0.43 mm, respectively) were significantly larger (p = 0.01; 0.009) than those of the SVS and OK groups, but no significant difference was found between the latter two groups (p > 0.05). Hence, photopic 1 and 2 measurements for the SVS and OK groups were pooled (SVS-OK) for further analyses. ICC for repeatability of the photopic measurements was 0.98 (95% CI, 0.96 to 0.99) for the SVS-OK and AOK groups. The differences between photopic 1 and 2 measurements were not significantly correlated with their means, either in the AOK group (Pearson's r = -0.25, p = 0.19), or in the pooled SVS-OK group (Pearson's r = -0.04, p = 0.78). BA plots also showed narrow 95% limits of agreement, and CoR was 0.25 mm and 0.23 mm in the AOK and pooled SVS-OK groups, respectively. CONCLUSION: Mesopic and photopic pupil size measurement using the NIDEK OPD-Scan III was highly repeatable and suitable for use on children.

One-year results of 0.01% atropine with orthokeratology (AOK) study: a randomised clinical trial.

PURPOSE: To report the 1-year results of an investigation into whether there is an additive effect between 0.01% atropine and orthokeratology (ortho-k), in a single-masked, two-arm, randomised controlled trial: Combined Atropine with Orthokeratology (AOK) for myopia control study (ClinicalTrials.gov number: NCT02955927). METHODS: Chinese children aged between 6 and 11 years with 1.00-4.00 D of myopia, astigmatism <2.50 D, and no more than 1.00 D anisometropia, were randomly assigned either to an AOK group or ortho-k only (OK) group at a 1:1 ratio. Subjects in the AOK group instilled one drop of 0.01% atropine into each eye, 10 min before nightly wear of ortho-k lenses. The primary outcome, axial elongation, was examined at 6-monthly intervals, along with secondary outcomes including best-corrected visual acuity (BCVA), manifest refraction, accommodation, pupil size, and corneal topography. RESULTS: 29 AOK and 30 OK subjects completed the 1-year visit. The overall axial elongation rate was significantly slower in the AOK group than in the OK group (mean (S.D.), 0.07 (0.16) mm vs 0.16 (0.15) mm, respectively; p = 0.03). A significant between-group difference in axial elongation was observed over the first 6-month period only (p < 0.001), but not over the second period (p = 0.818). At the 1-year visit, increases in mean (S.D.) mesopic and photopic pupil sizes in the AOK group were 0.64 (0.48) mm and 0.36 (0.34) mm, respectively, which were significantly higher than 0.10 (0.50) mm and 0.02 (0.28) mm in the OK group (p < 0.001). At the 6-month visit, a significant moderate negative correlation was found between axial elongation and the increase in photopic pupil size (r = -0.42, p = 0.02) in the AOK group. CONCLUSIONS: There is an additive effect between 0.01% atropine and ortho-k over one year, with mean axial elongation in the AOK group 0.09 mm slower than that in the OK group. It appears that the additive effect was only during the first six months; a second-year investigation is warranted to determine whether the effect is sustained over time.

Changes in Corneal Volume at Different Areas and Its Correlation with Corneal Biomechanics after SMILE and FS-LASIK Surgery.

PURPOSE: To investigate the variations of corneal volume (CV) after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and analyze the influences of biomechanical properties on the changes of refraction and CV. METHODS: Ninety-seven eyes of 97 patients undergoing SMILE and FS-LASIK were included in this retrospective study. CV was measured with Scheimpflug-based corneal topography at preoperatively and at day 1, week 1, and months 1 and 3 postoperatively. CV measured within 5 mm diameter was defined as central region volume (CV5) and between 5 mm and 10 mm diameter was defined as peripheral region volume (CV5-10). An Ocular Response Analyzer (ORA) was used to assess corneal biomechanical properties including corneal hysteresis (CH) and corneal resistant factor (CRF). The reduction of study parameters (△) were calculated by subtracting the preoperative value at various time points from the postoperative values. RESULTS: CV had significant reduction after the SMILE and FS-LASIK procedure (P < 0.05). CV5 increased significantly from postoperative day 1 to month 3 (P < 0.001) in SMILE, while both CV5 and CV5-10 increased significantly in FS-LASIK (P < 0.001). The increase in CV5 after SMILE was 0.11 ± 0.16 mm3，which was significantly different from FS-LASIK (0.20 ± 0.13 mm3, P=0.004). In the SMILE group, △CV5 correlated with △CRF (r = 0.498, P < 0.001) and △CH (r = 0.374, P=0.007). In the FS-LASIK group, △CV5 and △CRF had a significant correlation (r = 0.363, P=0.012), but not with △CH. CONCLUSIONS: Dynamic changes in corneal volume were found after SMILE and FS-LASIK surgery. The central region significantly increased after SMILE, while both central and peripheral regions increased following FS-LASIK in the early postoperative period. SMILE was associated with less change in biomechanical properties per unit of reduction in CV compared with FS-LASIK.

Combined Atropine with Orthokeratology for Myopia Control: Study Design and Preliminary Results.

Purpose: The purpose of this study is to present the study design and one month's preliminary results of a 2-year randomized trial, Combined Atropine with Orthokeratology (AOK), for myopia control study. Methods: Children aged 6 to <11 years and with 1.00-4.00 D myopia were randomly assigned to AOK group or ortho-k alone (OK) group. Subjects are required to attend routine ortho-k aftercare visits (first-overnight, 1 week, 2 weeks, 3 weeks, 1 month, and every 3 months after commencement of lens wear). Clinical outcomes, including lens performance, changes in refractive error, unaided vision, ocular adverse events, corneal staining, lens binding and centration, and axial length, are also assessed at 6-monthly data collection visit. Results: Data of 30 AOK and 34 OK subjects who had completed the 1-month visit were analyzed. No significant differences in baseline data were found between the two groups (P > 0.05). At the 1-month visit, first-fit success rate was 95%, with full myopia reduction. Mild corneal staining was observed in 23.3% and 30.9% and mild self-reported lens binding in 50% and 41% in AOK and OK groups, respectively, after 1-month lens wear. Mean (±standard deviation) change in axial length was significantly higher in AOK than OK subjects (AOK: -0.05 ± 0.05 mm; OK: -0.02 ± 0.03 mm) (P = 0.003). Conclusions: After 1 month of treatment, first-fit success rate of ortho-k lenses was high in both groups of subjects; addition of 0.01% atropine in AOK subjects did not affect the lens performance or clinical responses. These results provide the assurance that it is acceptable to continue this longitudinal study, as longer study duration, usually 2 years, is required to determine the effectiveness of treatment for myopia control.