A novel Lenslet-ARray-Integrated spectacle lenses for myopia control: a one-year randomized, double-masked, controlled trial.

PURPOSE: To investigate the myopia control efficacy of novel Lenslet-ARray-Integrated (LARI) spectacle lenses with positive (PLARI) and negative (NLARI) power lenslets worn for one year in myopic children. DESIGN: Randomized, double-masked, controlled clinical trial. PARTICIPANTS: A total of 240 children, aged 6 to 12 years, with spherical equivalent refraction (SER) between -4.00 and -1.00 diopter (D), astigmatism of 1.50 D or less, and anisometropia of 1.00 D or less. METHODS: Participants were assigned randomly in a 1:1:1 ratio to PLARI, NLARI, and a control (single-vision (SV)) groups. Cycloplegic autorefraction and axial length were measured at baseline and 6-month intervals after lens wear. MAIN OUTCOME MEASURES: Changes in SER, axial elongation (AE), and differences between groups. RESULTS: After 1-year, SER changes and AE in the PLARI and NLARI groups were significantly less than those in the SV group (SER: -0.30 ± 0.48 D, -0.21 ± 0.35 D, -0.66 ± 0.40 D; AE: 0.19 ± 0.20 mm, 0.17 ± 0.14 mm, 0.34 ± 0.18 mm, respectively) (all P < 0.001). There were no significant differences in SER changes and AE between PLARI and NLARI groups (P = 0.54 and P = 1.00, respectively). Younger age was associated with more rapid SER increase and larger AE in the SV (r = 0.40, P < 0.001 and r = -0.59, P < 0.001, respectively) and PLARI (r= 0.46, P < 0.001 and r = -0.52, P < 0.001, respectively) groups, but not in the NLARI group (r = -0.002, P = 0.98 and r = -0.08, P = 0.48, respectively). CONCLUSIONS: Compared with the SV group, both PLARI and NARI groups showed significantly slower myopia progression in terms of SER and axial elongation. Faster myopia progression, in terms of both SER and AE, was associated with younger age in the SV and PLARI groups, but not in the NLARI group.

Anisomyopia and orthokeratology for myopia control - Axial elongation and relative peripheral refraction.

PURPOSE: To investigate axial elongation (AE) and changes in relative peripheral refraction (RPR) in anisomyopic children undergoing orthokeratology (ortho-k). METHODS: Bilateral anisomyopic children, 7-12 years of age, were treated with ortho-k. Axial length (AL) and RPR, from 30° nasal (N30°) to 30° temporal (T30°), were measured at baseline and every 6 months over the study period. AE, changes in RPR and changes in the interocular AL difference were determined over time. RESULTS: Twenty-six of the 33 subjects completed the 2-year study. The AE of the higher myopic (HM) eyes (at least 1.50 D more myopia than the other eye) (0.26 ± 0.29 mm) was significantly smaller than for the less myopic (LM) eyes (0.50 ± 0.27 mm; p = 0.003), leading to a reduction in the interocular difference in AL (p = 0.001). Baseline RPR measurements in the HM eyes were relatively more hyperopic at T30°, N20° and N30° (p ≤ 0.02) and greater myopic shifts were observed at T20° (p < 0.001), T30° (p < 0.001), N20° (p = 0.02) and N30° (p = 0.01) after lens wear. After 2 years of ortho-k lens wear, temporal-nasal asymmetry increased significantly, being more myopic at the temporal locations in both eyes (p < 0.001), while AE was associated with the change in RPR at N20° (ß = 0.134, p = 0.01). The interocular difference in AE was also positively associated with the interocular difference in RPR change at N30° (ß = 0.111, p = 0.02). CONCLUSIONS: Ortho-k slowed AE in bilateral anisomyopia, with slower growth in the HM eyes leading to a reduction in interocular AL differences. After ortho-k, RPR changed from hyperopia to myopia, with greater changes induced in the HM eyes, and slower AE was associated with a more myopic shift in RPR, especially in the nasal field of both eyes.

Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study: A 2-year randomised clinical trial.

PURPOSE: To compare axial elongation (AE) and treatment zone (TZ) characteristics in children wearing 6 mm or 5 mm back optic zone diameter (BOZD) orthokeratology (ortho-k) lenses over 2 years. METHODS: Forty-five (6 to <11 years of age) myopic (-4.00 to -0.75 D) children of Chinese ethnicity were randomly assigned to use the two different lens designs (23 and 22 wore the 6 and 5 mm lenses, respectively). Data collection was performed at baseline and every 6-months after commencing lens wear. RESULTS: After 24 months, subjects wearing lenses with a 5 mm BOZD achieved smaller TZ diameter (horizontal: 2.69 ± 0.28 vs. 3.84 ± 0.39 mm; vertical: 2.65 ± 0.22 vs. 3.42 ± 0.34 mm, p < 0.001) and less AE (0.15 ± 0.21 vs. 0.35 ± 0.23, p = 0.005) compared to those using the 6 mm design, with no difference in choroidal thickness (ChT) changes (p = 0.93). A significant increase in ChT, using pooled data analysis, was noted at the 6-month (11.8 ± 19.77 µm, p < 0.001) and 12-month (12.0 ± 23.7 µm, p = 0.004) visits, compared to baseline, indicating a transient change in ChT. Significant associations were noted, using linear mixed models, between AE and the TZ diameters (p < 0.003) after adjusting for baseline data. A very weak association was found between ChT changes and AE, with the effect size close to zero. CONCLUSIONS: Smaller BOZD ortho-k lenses resulted in a smaller TZ diameter, which was associated with less AE after 2 years of treatment. The changes in ChT played a very weak role, suggesting that other factors may contribute more to the reduced AE in subjects wearing lenses having a smaller BOZD.

Comparison of compliance with care procedures performed by orthokeratology wearers and their parents and factors affecting compliance.

PURPOSE: To compare the levels of compliance with care routines of orthokeratology (ortho-k) wearers and their parents and to identify factors affecting compliance in a hospital setting in Chengdu, China. METHODS: Patients who had worn ortho-k lenses for at least one month were invited to participate in a survey on compliance. Wearers or their parents were required to complete a questionnaire to determine their compliance with hand hygiene, ortho-k lenses and accessory care procedures. RESULTS: A total of 200 wearers, 78 male wearers and 122 female wearers, median age 12 (range 8-18) years were enrolled. Except for use of lens solution, the percentage of participants reporting total compliance with all procedures did not differ significantly between lens wearers and their parents. However, compliance for some items was significantly higher when performed by parents p < 0.001-0.01). 'Eye care practitioner provided instructions' was a significant protective factor for most procedures (p < 0.001-0.04). Age and sex were significant risk factors for some items (p < 0.001-0.04; p = 0.03-0.04, respectively), with girls having higher compliance than boys. 'Parental supervision' was a significant protective factor for some items (p = 0.02-0.04) when wearers performed the procedures themselves. When parents performed lens care procedures, only 'eye care practitioner provided instructions' was a significant variable (p = 0.001-0.04). CONCLUSION: Some degree of non-compliance was noted in the majority of ortho-k wearers, particularly for the care of the lens case and suction holder. Compliance with care of some items was higher when performed by parents. Regular reinforcement of care procedures by practitioners is important, especially for older and male lens wearers. Parental supervision is necessary when children perform lens care procedures themselves, even for older wearers.

Manual and software-based measurements of treatment zone parameters and characteristics in children with slow and fast axial elongation in orthokeratology.

PURPOSE: To compare the treatment zone (TZ) measurements obtained using manual and software-based methods in orthokeratology (ortho-k) subjects and explore the TZ characteristics of children with slow and fast axial elongation after ortho-k. METHODS: Data from 69 subjects (aged 7 to <13 years old), who participated in three 24-month longitudinal orthokeratology studies, showing fast (>0.27 mm, n = 38) and slow (<0.09 mm, n = 31) axial elongation, were retrieved. The TZ after ortho-k was defined as the central flattened area enclosed by points with no refractive power change. TZ parameters, including decentration, size, width of the peripheral steepened zone (PSZ), central and peripheral refractive power changes and peripheral rate of power change, were determined manually and using python-based software. TZ parameters were compared between measurement methods and between groups. RESULTS: Almost all TZ parameters measured manually and with the aid of software were significantly different (p < 0.05). Differences in decentration, size and the PSZ width were not clinically significant, but differences (0.45 to 0.92 D) in refractive power change in the PSZ were significant, although intraclass coefficients (0.95 to 0.98) indicated excellent agreement between methods. Significantly greater TZ decentration, smaller TZ size and greater inferior rate of power change (relative to the TZ centre) were observed in slow progressors using both methods, suggesting a potential role of TZ in regulating myopia progression in ortho-k. CONCLUSION: TZ measurements using manual and software-based methods differed significantly and cannot be used interchangeably. The combination of TZ decentration, TZ size and peripheral rate of power change may affect myopia control effect in ortho-k.

Differences in Practitioner Experience, Practice Type, and Profession in Attitudes Toward Growing Contact Lens Practice.

OBJECTIVE: To investigate eye care practitioners' attitudes and perceptions toward potential interventions that can enhance contact lens (CL) practice across the world, and how this is influenced by their practice setting. METHODS: A self-administered, anonymized survey was constructed in English and then forward and backward translated into six more languages. The survey was distributed online via social media platforms and mailing lists involving reputed international professional bodies. RESULTS: In total, 2,222 responses from 27 countries with sufficient responses were analyzed (53% females, median age- 37 years). Most of the respondents were optometrists (81.9%) and 47.6% were from stand-alone/independent practices. Median working experience in CL prescribing was 11.0 years (IQR: 18.0, 4-22 years). Over two-third of them declared themselves to be very hopeful (22.9%) or hopeful (45.1%) about the future of their CL practice. Among the potential interventions proposed, continuous update of knowledge and skills and competently managing CL-related complications were rated the most important (median score: 9/10 for each). Practitioners working in national/regional retail chains expressed higher proactivity in recommending CLs (9/10) than those in local chains, hospitals, and universities (for all 8/10, P <0.05). National differences were also identified in eye care practitioner attitudes and perceptions ( P <0.05). CONCLUSIONS: The study provided important information to delineate a variety of elements characterizing CL practice across the world. These insights can serve as a basis to design strategies at national and international levels.

Analysis of parental decisions to use orthokeratology for myopia control in successful wearers.

PURPOSE: To investigate factors that influence parental decisions to use orthokeratology (ortho-k) as a myopia control method for their children, and parents' perspectives during children's ortho-k treatment in a hospital setting. METHODS: Parents/guardians of children wearing ortho-k lenses for at least six months were required to complete a face-to-face survey to investigate the reasons for choosing ortho-k and their experience of the treatment. RESULTS: Parents/guardians of 128 ortho-k wearers were recruited from the West China Hospital, Sichuan, China. The majority of the participants (74%) were mothers. Wearers' mean age at the time of the survey was 12.0 ± 2.0 years, with a mean history of ortho-k lens wear of 20.3 ± 8.0 months. Most participants had learned about ortho-k through word of mouth (56%) or from ophthalmologists (40%); in China, only ophthalmologists may prescribe ortho-k. The highest ranked motivation was the rapid progression of their children's myopia (54%), followed by ophthalmologists' advice (17%) or participants' who felt they had obtained enough knowledge (17%) of ortho-k (Kruskal-Wallis test, p = 0.002). 'Effectiveness' was the most common reason that participants decided to use ortho-k (81%), and potential injury was their major concern (75%). Itchy/sore eye was the most common initial adverse effect experienced with lens wear (22%), while a lost or broken ortho-k lens was the most frequently reported problem (34%). Parents of older lens wearers were significantly less involved in all procedures (Spearman rank correlation test, all p < 0.001). Most wearers, according to either the participants or the wearers themselves, were willing to wear ortho-k lenses at treatment commencement (80%), and the most common reason was 'to avoid having to wear spectacles in the daytime'. CONCLUSIONS: The most powerful motivation for parents to enrol their children in ortho-k treatment was the rapid progression of myopia. The main reason why participants chose ortho-k, which most participants learned of by word of mouth, was the effectiveness of the treatment. During use, the most common symptom reported was itchy or sore eyes, but only initially. Children's willingness to participate is very important for successful ortho-k treatment; however, their motivation can be quite different from that of their parents. Ortho-k is a well-accepted option for myopia control in children.

One-year results of the Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study: a prospective randomised clinical trial.

PURPOSE: To present the 1-year results of the Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study, which aims to investigate the myopia control effect of orthokeratology (ortho-k) lenses with different back optic zone diameters (BOZD). METHOD: Children, aged 6 to <11 years, having myopia -4.00 D to -0.75 D, were randomly assigned to wear ortho-k lenses with 6 mm (6-MM group) or 5 mm (5-MM group) BOZD. Data collection included changes in refraction, vision, lens performance and binding, ocular health conditions, axial length and characteristics of the treatment zone (TZ) area. RESULTS: The 1-year results of 34 and 36 subjects (right eye only) in the 6-MM and 5-MM groups, respectively, are presented. No significant differences in baseline demographics were found between the groups (p > 0.05). The first-fit success rates, based on satisfactory centration at the 1-month visit, were 100% and 94% respectively. Horizontal TZ size was 0.92 mm and 0.72 mm smaller in the 5-MM group at the 6-month and 12-month visits, respectively (p < 0.05). At the 12-month visit, no significant between-group differences were found in the incidence of corneal staining (low grade only), lens binding and visual performance (all p > 0.05). Axial elongation was slower in the 5-MM group (0.04 ± 0.15 mm) than the 6-MM group (0.17 ± 0.13 mm) (p = 0.001). A significant positive correlation was observed between the horizontal TZ size and axial elongation (r = 0.36, p = 0.006). CONCLUSION: Clinical performance of the two ortho-k lenses was similar, indicating that a smaller BOZD (5 mm) did not affect lens performance or ocular integrity. However, a smaller BOZD led to a reduced TZ, with retardation of axial elongation by 0.13 mm compared to conventional 6 mm BOZD ortho-k lenses after one year of lens wear.

Comparison between estimated and measured myopia progression in Hong Kong children without myopia control intervention.

PURPOSE: To compare myopia progression estimated by the Brien Holden Vision Institute (BHVI) Myopia Calculator with cycloplegic measures in Hong Kong children wearing single-vision distance spectacles over a 1- and 2-year period. METHODS: Baseline age, spherical equivalent refraction (SER) and ethnicity of control participants from previous longitudinal myopia studies were input into the BHVI Myopia Calculator to generate an estimate of the SER at 1 and 2 years. Differences between the measured and estimated SER (116 and 100 participants with 1- and 2-year subjective refraction data, respectively, and 111 and 95 participants with 1- and 2-year objective refraction, respectively) were analysed, and the measured SER compared with the 95% confidence interval (CI) of the estimated SER. RESULTS: In children aged 7-13 years, 36% progressed within the 95% CI of the Myopia Calculator's estimate, whereas 33% became less myopic than predicted (range 0.31 to 1.92 D less at 2 years) and 31% became more myopic than predicted (range 0.25 to 2.33 D more myopic at 2 years). The average difference between the estimated and measured subjective or objective SER at 1 and 2 years of follow-up was not clinically significant (<0.25 D). CONCLUSIONS: On average, the BHVI Myopia Calculator estimated SER was in close agreement with measured cycloplegic SER after 1 and 2 years of follow-up (mean differences < 0.25 D). However, the measured myopia progression only fell within the 95% CI of the estimated SER for 32%-38% of children, suggesting that the BHVI 'without management' progression data should be interpreted with caution. The inclusion of additional data, modified to include axial elongation, from longitudinal studies of longer duration with larger sample sizes and a range of racial backgrounds may improve the Calculator's ability to predict future myopia progression for individual children.

Corneal thickness changes in myopic children during and after short-term orthokeratology lens wear.

PURPOSE: To evaluate thickness changes in the central and mid-peripheral cornea (CCT and mPCT), corneal epithelium (CET and mPET) and stroma (CST and mPST) of myopic children during and after short-term orthokeratology (ortho-k) lens wear, with conventional (CCF, 0.75 D) and increased compression factors (ICF, 1.75 D). METHODS: This was a self-controlled case series study. Subjects wore a CCF lens in one eye and an ICF lens in the other. Anterior segment optical coherence tomography images were captured weekly for 1 month during lens wear and for 2 weeks after discontinuing lens wear. CCT and CET (central 3-mm cornea) and mPCT and mPET (within a 4-6 mm diameter annulus) were measured. Stromal thickness (ST) was determined by subtracting epithelium thickness (ET) from corneal thickness (CT). The repeatability of the analytical software was also investigated on age-matched spectacle-wearing subjects (n = 98). RESULTS: Excluding three outliers (>3 S.D.s), the coefficient of repeatability and intraclass correlation coefficients of 98 spectacle-wearing subjects ranged from 2.63 to 4.64 µm and from 0.90 to 0.99, respectively. For the weekly-change study, CCT and CET in both eyes were significantly thinner after lens wear (p < 0.001) and CET thinning in the ICF eyes were significantly higher (p < 0.02). CCT changes were mainly contributed by CET. CST, mPCT, mPET and mPST changes were not significant (p > 0.20) in either eye. CT (all sublayers) rebounded to baseline values 2 weeks after discontinuing lens wear (0.99 > p > 0.12). CONCLUSIONS: Significant reductions in CT and ET, but not ST, were observed within 1 month of ortho-k lens wear. Wearing ICF lenses resulted in a higher reduction in CET. Corneal thickness changes were reversible after discontinuing lens wear.

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.

To rub or not to rub? - effective rigid contact lens cleaning.

PURPOSE: To compare the efficacy of cleaning of rigid contact lenses using two care solutions with and without rubbing. METHODS: A masked randomised trial was conducted. The cleaning efficacy of two solutions recommended for rigid contact lenses, a one-step hydrogen peroxide solution (HP) and a povidone iodine-based solution (PI), were evaluated on 64 unworn orthokeratology (ortho-k) lenses subsequent to cleaning with rubbing (R) with a surfactant cleaner or without rubbing (NR). Either mascara or hand cream was applied as a contaminant to the lenses to simulate stubborn and loosely bounded deposits, respectively. For each type of deposit, the lenses were randomly assigned to four cleaning treatments: R with HP, NR with HP, R with PI, and NR with PI (n = 8 for each group). Each lens surface was assessed on site by a masked examiner under a low-magnification slit-lamp and with photo-documentation. Lenses were graded according to the deposit coverage area using a pre-set five-point scale [0 (<20% coverage) - 4 (>80% coverage)]. RESULTS: For stubborn deposits (mascara), NR failed to remove deposits from 94% of lenses, whilst R removed more than 80% of deposits from 63% of the lenses. For oily deposits, 25% of NR lenses had >80% coverage, whilst only one R lens had 60-80% coverage, with 19% having 40-60% coverage, and 38% with either 20-40% or <20%. Rubbing improved lens cleanliness for both types of deposits, but only reached statistical significance for the stubborn deposit group. There were no significant differences between the solutions. CONCLUSION: Not Rubbing and using either HP or PI solutions, is not effective in removing stubborn deposits from ortho-k lenses. It is essential to rub lenses when cleaning rigid lenses to ensure optimal lens hygiene for ocular health, especially as rigid gas permeable (RGP) lenses are intended to be reused for at least a year before replacement. Rubbing with a daily cleaner should be included in the instructions for use of the solutions tested for rigid lenses and practitioners should be encouraged to emphasise the importance of rubbing in lens care.

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.

Higher order aberrations and axial elongation in combined 0.01% atropine with orthokeratology for myopia control.

PURPOSE: To compare the changes in higher order aberrations (HOA's) for photopic and mesopic pupil diameters in children undergoing orthokeratology treatment (OK) or combined 0.01% atropine with orthokeratology treatment (AOK), and their association with axial elongation. METHODS: Children aged 6 to <11 years with 1.00-4.00 D of myopia were randomly assigned to each treatment group. Photopic and mesopic pupil diameters were quantified using automated pupillometry and HOA's were measured with a Hartmann-Shack aberrometer and Badal system to control for accommodation. HOA's were rescaled to photopic and mesopic pupil diameters and fitted with a 6th order Zernike polynomial expansion. Axial length was measured using an optical biometer under cycloplegia. RESULTS: Baseline and six-month data from 25 AOK and 28 OK participants were analysed. At the six-month visit, pupil diameter was larger in the AOK group under photopic conditions (3.70 ± 0.42 vs 3.12 ± 0.33 mm, p < 0.001), along with a range of HOA metrics [3rd to 6th order and higher order root mean square error values (HO RMS), all p ≤ 0.003] and individual Zernike terms (primary spherical aberration, and oblique quadrafoil, both p ≤ 0.03). Axial elongation was greater in the OK treatment group (0.05 ± 0.08 vs -0.01 ± 0.12 mm, p = 0.02). In the AOK group, axial elongation was correlated with the increase in photopic pupil diameter (r = -0.45, p = 0.02) and with several HOA metrics; however, these associations were not observed in the OK group. CONCLUSION: AOK treatment resulted in increased photopic pupil size and HOA's, and significantly less axial elongation over a six-month period compared to OK treatment alone. The improved myopia control observed with combination 0.01% atropine and orthokeratology may be a result of an enhanced optical effect due to a larger photopic pupil size.

Does Long-Term Rigid Contact Lens Wear Lead to Acquired Blepharoptosis in Chinese Eyes?

OBJECTIVES: To determine whether long-term rigid contact lens wear leads to acquired blepharoptosis and whether its development is affected by lens removal methods. METHODS: Ninety rigid contact lens wearers (45 rigid gas permeable [RGP] [15-19 years old] and 45 ortho-k [15-40 years old]) who had worn lenses for at least 2 years and 45 spectacle-wearing controls (15-19 years old) were recruited. Margin reflex distance (MRD) and palpebral fissure height (PFH) were measured both subjectively and objectively, but levator function (LF) could only be measured subjectively. For RGP subjects, measurements were made before and 5 min after lens removal. Measurements were compared among the groups and, for rigid lens wearers, between two different lens removal techniques: using a suction holder or by finger-lid manipulation. RESULTS: No significant differences in MRD, PFH, and LF were found between different lens removal techniques in the rigid lens groups (P>0.05). No significant correlations were found between the parameters of interest and duration of lens wear (P>0.05). For the RGP group, MRD, PFH, and LF were significantly greater after than before lens removal (P<0.05), and after lens removal, MRD was significantly smaller than that of the ortho-k and spectacle groups (P<0.001, P=0.01, respectively) and PFH was significantly smaller than that of the ortho-k group (P=0.001). However, after lens removal, according to the definition (amount) for ptosis, no subject was diagnosed as having ptosis. CONCLUSIONS: Long-term rigid contact lens wear did not lead to acquired blepharoptosis in Chinese eyes. Margin reflex distance, PFH, and LF were not affected by different lens removal techniques.

Evaluation of prevention and disruption of biofilm in contact lens cases.

PURPOSE: The presence of biofilm in the lens case has been shown to be a risk factor for contamination of lenses and consequently microbial keratitis. This study aimed to evaluate effectiveness of solutions for rigid contact lenses in prevention and disruption of biofilm in lens cases and methods for biofilm detection. METHOD: This study adopted a stepwise approach to evaluate effectiveness of four rigid lens disinfecting solutions against biofilm. These included two polyhexamethylene bigiuanide (PHMB) solutions and a chlorhexidine/PHMB-based solution, as well as a novel povidone-iodine formulation. The presence of biofilm following exposure to the solutions was assessed using both crystal violet (CV) staining and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) viability assay, taking into account the effect of lens case design. Three lens case designs, conventional flat, large bucket type, and cylindrical cases, were investigated for the ability to trap stain and allow biofilm formation. RESULTS: Considerable differences were noted between solutions in their ability to prevent and disrupt biofilm (p < 0.001). Lens case design greatly influenced optical density (OD) measurements even in negative controls, as cylindrical cases trapped more stain, increasing OD readings. Correcting for this factor reduced variations, but could not differentiate between residues and biofilm. MTT assay revealed that both povidone-iodine and chlorhexidine-containing solutions could effectively kill > 95% of organisms, whilst PHMB-based solutions were less effective with up to 55% of staphylococci and 41% of Pseudomonas surviving at 24 h. CONCLUSION: Biofilm can rapidly form in lens cases and may not be killed by disinfecting solutions. Of the solutions tested, none were able to prevent biofilm formation or disrupt established biofilm, but those containing chlorhexidine or povidone iodine were able to penetrate the biofilm and kill organisms. Assessment of biofilm by CV assay may be confounded by lens case design. Whilst CV assay can demonstrate presence of biofilm, this technique should be accompanied by viability assay to determine bactericidal activity.

Prevalence of antiseptic resistance genes increases in staphylococcal isolates from orthokeratology lens wearers over initial six-month period of use.

The purpose of this study was to investigate the prevalence of antiseptic-resistance (QAC) genes in staphylococci colonizing periorbital tissues and accessories of orthokeratology (ortho-k) lens wearers over a 6-month period and determine the effect of their presence on minimum inhibitory (MIC) and bactericidal concentrations (MBC) of disinfectants and log reduction of multipurpose contact lens solutions (MPS). Staphylococci were isolated from periorbital tissues and accessories of patients before commencing ortho-k therapy and at two subsequent visits. Presence of QAC genes in 116 S. aureus and 67 CNS isolates was determined by PCR and association with period of ortho-k use determined. MICs and MBCs of staphylococci gene-positive were compared with gene-negative strains and the effectiveness of four MPS for rigid contact lenses investigated. S. aureus carriage rates in the conjunctiva decreased significantly from 41.2 % (baseline) to 11.8 % (3-months), and 13.3 % (6-months) (p trend 0.03), while CNS increased from 58.8 %(baseline) to 94.1 % (3-months), and 93.3 % (6-months) (p trend 0.02). Prevalence of qacA/B increased considerably over time (S. aureus: 4.4 % to 15.4 %, CNS: 6.7 % to 25 %), but frequency of smr was relatively stable. Only five CNS isolates harboured qacH. MICs and MBCs of gene-positive isolates were significantly increased and three MPS did not achieve a 3-log reduction of many QAC-positive strains. Ortho-k lens wear contributed to changes of staphylococcal carriage rates in the conjunctival sac. Use of MPS containing quaternary ammonium compounds may select for the carriage of organisms harbouring QAC genes, as the low concentration of disinfecting agents is not adequate for killing gene-positive strains.

Microbial Contamination of Periorbital Tissues and Accessories of Children.

PURPOSE: To investigate normal flora of children with and without orthokeratology (ortho-k) treatment, and the associations between carriage of Staphylococcus aureus and Gram-negative rods with contamination of contact lenses and lens cases in ortho-k subjects and with spectacles of control subjects. METHODS: Twenty-three ortho-k subjects (treatment >12 months) and 20 control myopic subjects aged 7-14 years were recruited. Samples were collected from four sites surrounding the left eye (lower conjunctiva, upper and lower eyelids, and eyelashes) for all subjects, spectacles for control subjects and contact lens accessories for ortho-k subjects. Samples were cultured, total numbers enumerated, and isolates identified using chromogenic agars. RESULTS: Ortho-k subjects had significantly less total isolates in the conjunctiva than controls (p = 0.009). Otherwise, carriage rates in normal flora levels of the peri-orbital tissues were not significantly different between the two groups (p > 0.19). The total isolates and carriage rates of normal flora on spectacles, contact lenses, and lens cases were similar to those identified on the skin tissues. Small numbers of bacteria were identified from the multipurpose solution of two ortho-k subjects. Although the association between the carriage of S. aureus with contamination of accessories was statistically significant only in control subjects (p = 0.03), ortho-k subjects not yielding S. aureus and Gram-negative rods from samples of their peri-orbital tissues tended to be less likely to have these organisms in their accessories. No Pseudomonas was isolated from any of the sites sampled and no Acinetobacter was isolated from any of the accessories. CONCLUSIONS: Ortho-k may lower the total number of bacteria in conjunctiva due to the use of solution and lenses, but the physiologic effect of this treatment on the types of normal flora in children was minimal and should not increase the risk of microbial keratitis in children with good compliance.

Parents' knowledge and perspective of optical methods for myopia control in children.

PURPOSE: To solicit parents' knowledge on myopia control strategies available; to investigate their attitudes toward the use of orthokeratology (ortho-k), daily wear soft lenses, and spectacles for myopia control, assuming all three optical strategies were equally effective for myopia control; and to collect their opinion on the age at which children can commence contact lens wear for vision correction. METHODS: Telephone interviews were conducted on parents who responded to the advertisement for two myopia control studies, one on ortho-k and one on soft lenses. RESULTS: Most of the 196 respondents (ortho-k group, 56%; soft lens group, 44%) were mothers, aged 36 to 45 years. Ortho-k was the most commonly known myopia control strategy (86%). Parents in the ortho-k group selected ortho-k (49%) and spectacles (45%) (p < 0.001) as their preferred myopia control strategy, whereas parents in the soft lens group had no preference (p = 0.57). Decision was affected by prior knowledge of myopia control strategy. Major considerations were convenience and safety among parents selecting contact lenses and spectacles, respectively, as their preferred options. Overall, because of the lack of confidence in safety in contact lens wear, most parents (75%) were of the opinion that contact lenses for vision correction were only for children older than 14 years (53%) and not indicated for children younger than 8 years. CONCLUSIONS: Parents in Hong Kong were open to the use of contact lenses for myopia control in young children and they appeared to regard myopia control contact lenses as "treatment" and not as visual aids. They were more conservative in the use of contact lenses for vision correction in children. Parents' decision in selecting a myopia control strategy, assuming all three strategies to be equally effective, was affected by an individual's concerns of safety and additional benefits as well as influenced by positive evidence on myopia control effects.