Orthokeratology Research Articles

Effects of different orthokeratology lens designs on slowing axial length elongation in children with myopia.

To elucidate whether differences exist in the impact on retarding the elongation of axial length (AL) among children with myopia when utilizing orthokeratology (ortho-k) lenses employing the corneal refractive therapy (CRT) design versus those employing the vision shaping treatment (VST) design. This retrospective clinical trial aimed to collect and analyze AL data from individuals who wore ortho-k lenses for three years. A total of 654 subjects were enrolled and prescribed one of the three specific brands of ortho-k lenses: CRT, Euclid, and Mouldway. The study's primary focus was to compare the rates of AL elongation and myopic progression across these three brands of ortho-k lenses. In the 3-year follow-up, the AL elongation exhibited variations of 0.73±0.36 mm in the CRT lens group, 0.59±0.37 mm in the Euclid lens group, and 0.63±0.38 mm in the Mouldway lens group. A noteworthy disparity emerged between the CRT and Mouldway groups (P<0.01), as well as between the CRT and Euclid groups (P<0.001). Additionally, it was observed that 32.1% of participants who wore CRT lenses experienced a decelerated progression of myopia, in contrast to 47.2% in the Euclid group and 44.4% in the Mouldway group. Statistical analyses revealed a statistically significant distinction between the CRT and Euclid groups (P<0.01), and similarly, the CRT group demonstrated a statistically significant difference when compared to the Mouldway group (P<0.05). Ortho-k lenses represent a pragmatic strategy for mitigating the advancement of myopia. In contradistinction to ortho-k lenses utilizing the CRT design, those employing the VST design exhibited a more favorable impact regarding retarding AL elongation.

Effects of orthokeratology and spectacle lenses with highly aspherical lenslets on unilateral myopic anisometropia control.

To evaluate the 1-year effects of orthokeratology (OK) lenses and spectacle lenses with highly aspherical lenslets (HALs) on axial length (AL) elongation in children with unilateral myopic anisometropia. This ambispective cohort study recruited 81 children aged 8-14 years with unilateral myopic anisometropia. Of these, 42 participants (mean age 11.07 ± 1.54 years; 23 males) were treated with monocular OK lenses (OK group), and 39 (mean age 10.64 ± 1.72 years; 22 males) with binocular HALs (HAL group). Changes in AL and spherical equivalent refraction (SER) from baseline at 3, 6 and 12 months were compared between eyes and groups. Kaplan-Meier estimation and Cox proportional hazard regression were performed to analyse the risk of myopia onset in the initially non-myopic eyes. Mean axial elongation in the myopic and non-myopic eyes at the 12-month follow-up visit were 0.17 ± 0.20 and 0.41 ± 0.26 mm in the OK group (p < 0.001) and 0.10 ± 0.15 and 0.12 ± 0.12 mm in the HAL group (p = 0.32), respectively. Compared with the OK group, the non-myopic eyes in the HAL group had less axial elongation, lower cumulative myopia incidence and percentage of participants with rapid myopic shift at the 6- and 12 month follow-up (all p < 0.05). Cox regression analysis showed that a higher initial SER decreased the risk of myopia onset significantly in the initially non-myopic eyes (B = -2.06; 95% CI, 0.03-0.49; p = 0.003). Monocular OK lenses suppressed axial elongation in the myopic eye and minimised anisometropia; however, the non-treated contralateral eye may experience faster myopia onset and myopic shift. Binocular HALs can effectively reduce axial elongation in both eyes of children with unilateral myopic anisometropia.

Comparison of the Effects of Orthokeratology and Highly Aspherical Lenselets in Achieving Myopia Control and Defocus in Adolescents.

To compare the control effectiveness and periretinal defocus between orthokeratology (OK) and highly aspherical lenslets (HAL) in adolescents with myopia. In this prospective study, 211 children (211 right eyes) were enrolled in Beijing Ming Vision and Ophthalmology between October 2022 and February 2023. Based on the myopia correction method, participants were divided into three groups: OK, HAL, and single-vision spectacles (SVS). They were further divided into two subgroups according to the spherical equivalent (SE), namely, subgroup A with -1.0≤SE≤-2.0 D and subgroup B with -2.0<SE≤-3.0 D. All children were followed up for 12 months, and the changes in axial length (AL) and periretinal defocus before and after treatment were recorded, and the factors affecting the corneal shaping force for 1-day post-OK were analyzed. Axial length growth in those with OK lenses and HAL was lower than what was observed for those with SVS after 6, 9, and 12 months. Comparison of the difference in AL change between OK and HAL was not statistically significant with -1.0≤SE≤-2.0 D. The myopic defocus of RDV270° to 300° in group HAL was higher than that in group OK, the difference was statistically significant ( P <0.05), and in other regions, the myopic defocus was higher in the group OK. Em, SRI (corneal regularity index), variation in cell area, and corneal thickness were significantly associated with shaping force. Orthokeratology is one of the most effective optical treatments for controlling myopia, and the factors that affect the corneal shaping force under different corneal parameters are different. For mild myopia, HAL can achieve the same effectiveness as OK.

Layer-by-layer self-assembled smart antibacterial coatings for surface management of orthokeratology lens

ABSTRACT Orthokeratology (OK) lenses are designed to reshape the cornea overnight, allowing users to see clearly during the day without glasses. However, prolonged wear increases the risk of microbial contamination and eye infections. Even with cleaning techniques, the surface of OK lenses can become contaminated due to residual bacterial debris. Therefore, developing self-cleaning antibacterial technology for OK lens surfaces is an urgent clinical challenge. Herein, we integrated the temperature responsiveness of PNIPAM molecular chains with the surface contact-killing mechanism of AMP into the surface of OK lenses for the first time, constructing an intelligent OK lens with synergistic antibacterial and self-cleaning properties. The modified OK lenses can achieve over 95% bacterial efficiency against Staphylococcus aureus and Pseudomonas aeruginosa. More importantly, in both worn and removed states, the modified OK lenses can achieve a surface bacterial debris self-cleaning efficiency of 50–75%. These research findings provide important references and insights for the future development of more efficient self-cleaning lens materials.

A protocol for a single center, randomized, controlled trial assessing the effects of spectacles or orthokeratology on dry eye parameters in children and adolescents

BackgroundThe prevalence of myopia among adolescents is increasing precipitously in China, and the popularity of orthokeratology (OK) lenses as an effective treatment for controlling myopia progression is rising. This protocol assessed and compared the clinical dry eye parameters in children and adolescents with myopia treated with spectacles or OK lenses. Methods and analysisThis single-masked randomized control trial will include 300 participants (aged 8–17 years) with myopia treated with OK lens (study group) or spectacles (control group). We will record the ocular surface disease index, visual analog scale score, noninvasive tear breakup time, tear meniscus height, meibomian gland score, ocular redness score, visual acuity, tear Matrix Metalloproteinase-9 concentration, tear Lymphotoxin alpha levels at baseline, and after 1-, 3-, 6-, and 12-month. DiscussionThis study will be a standardized, scientific, clinical trial designed to evaluate the dry eye parameters in children and adolescents with myopia treated with OK lenses for myopia control. Ethics and disseminationThis study has been approved by the Ethics Committee of He Eye Specialist Hospital [ethics approval number: IRB(2023)K024.01]. Before participating in the trial, written informed consent will be obtained from all patient's parents or guardians. The findings of this study will be showcased at both local and international conferences and will also be submitted for publication in reputable peer-reviewed journals. Trial registration numberClinicaltrials.gov: NCT06023108 {2a, 2b}

The efficacy of orthokeratology lenses with smaller back optic zone diameter in myopia control. A meta-analysis.

This study was conducted to determine whether orthokeratology (OK) lenses with a smaller back optic zone diameter (BOZD) could exhibit stronger myopia control effects. A meta-analysis was registered in PROSPERO (CRD42023408184). A comprehensive systematic database search was conducted, encompassing PubMed, Cochrane Library, EMBASE, MEDLINE, Web of Science, Ovid, CNKI and CBM, to identify relevant studies up to 25 March 2023. The primary inclusion criteria for this meta-analysis were studies that investigated the myopia control effect of OK lenses with a small optical treatment area (≤5 mm). To assess the quality of the retrieved articles, two researchers evaluated them using the Cochrane bias risk assessment criteria. The primary outcome measures were the changes in axial length (AL) and refractive error, using the weighted mean differences (WMD) and 95% confidence intervals (CI) to assess differences between small and traditional back optical treatment zone groups in terms of these outcomes. The analysis encompassed five eligible studies, with a 1 year duration. The average difference in AL between the groups was 0.12 mm (WMD = -0.12, 95% CI [-0.16, -0.09], p < 0.00001). Likewise, the average difference in refractive error between the two groups was 0.44 D (WMD = 0.44, 95% CI [0.30, 0.57], p < 0.00001). None of the studies reported severe adverse events. Current evidence suggests that OK lenses with smaller back optical treatment zone are more effective in preventing myopia progression than traditional lenses. However, a longer-term evaluation is warranted.

12-months + 1: Adverse events and ocular surface evaluation with invasive and non-invasive method in orthokeratology (OK) wearers

12-months + 1: Adverse events and ocular surface evaluation with invasive and non-invasive method in orthokeratology (OK) wearers

Three optical intervention methods for low myopia control in children: a one-year follow-up study

ObjectiveThis study aimed to compare the one-year efficacy of myopia prevention and control using three optical intervention methods - single vision lens (SVL), highly aspherical lenslet (HAL), and orthokeratology (OK) lens - in children with low myopia.MethodsA cohort of 150 children aged 7–13 years with low myopia was recruited and divided into three groups: SVL (n = 50), HAL (n = 50), and OK lens group (n = 50), based on their preference for glasses. Follow-up assessments were carried out over one year, focusing on data from the right eye for statistical analysis. Baseline characteristics such as gender, age, axial length (AL), spherical equivalent refractive error (SER), flat keratometry (K1), steep keratometry (K2), anterior chamber depth (ACD), white-to-white corneal diameter (WTW), and non-contact tonometry (NCT) measurements were gathered and compared among the three groups before any intervention. Changes in AL growth after 1 year of intervention were assessed across the three groups. Subsequently, the AL growth control rates between the HAL and OK lens groups were compared, with the SVL group serving as the reference standard.ResultsThe study found no statistically significant variances in baseline characteristics (gender, age, SER, AL, K1, K2, WTW, and NCT) among the SVL, HAL, and OK lens groups (all p > 0.05). Following a one-year intervention, AL growth rates were as follows: HAL group (0.163 ± 0.113 mm) < OK lens group (0.280 ± 0.170 mm) < SVL group (0.516 ± 0.190 mm), with statistically significant disparities (p < 0.05). The HAL group demonstrated a higher 1-year AL growth control rate (68.41%) compared to the OK lens group (45.74%) for children aged 7–13 with low myopia, with a statistically significant differences (p < 0.001). And there was significant difference in the SER change between SVL group and HAL group (p < 0.001).ConclusionCompared to SVL, HAL and OK lens are more effective in controlling axial growth in mild myopia. Specifically, HAL maybe shows superior outcomes in both preventive and corrective measures, also it needs to be supported by more studies from randomized controlled experiments.

Add-on effect of using 0.05% atropine in fast progressors of orthokeratology: A preliminary retrospective study

PurposeTo investigate the potential benefit of combining orthokeratology (OK) lenses with 0.05% atropine ophthalmic solution on the efficacy of myopia control in the fast progressors of OK. MethodsAverage axial length (AL) elongation of both eyes in 70 participants using OK lenses alone or OK lenses combined with 0.05 % atropine ophthalmic solution was retrospectively reviewed. During the observation period (phase 1), all participants exhibited an AL elongation that exceeded 0.15 mm over a 6-month period or 0.3 mm over a 12-month period. Subsequently, the participants were divided into two groups: one group received nightly 0.05 % atropine ophthalmic solution in addition to OK lenses for another 1 year (OKA), while the other group continued using OK lenses alone (phase 2). The changes in AL elongation over time and the differences in AL elongation between the two groups were then compared. ResultsThe baseline and phase 1 demographics and characteristics of the participants was similar between the two groups (all p > 0.05). when considering a one-year timeframe, the OKA group displayed a significantly less AL elongation compared to the OK group (0.14 ± 0.13 mm vs 0.27 ± 0.12 mm, p < 0.001). Within the OKA group, the AL elongation in the second half of the year was significantly faster than in the first half (0.12 ± 0.11 mm vs 0.02 ± 0.14 mm, p = 0.01). Conversely, there was no significant difference in AL elongation between the OK group in the first and second half of the year (0.12 ± 0.07 mm vs 0.15 ± 0.08 mm, p = 0.71). The combination of 0.05 % atropine ophthalmic solution had a significant effect on 1-year AL elongation (p < 0.001). ConclusionsThis study provided preliminary evidence that the combination of OK lenses and 0.05% atropine ophthalmic solution can significantly enhance the effectiveness of myopia control.

Changes in the Objective Vision Quality of Adolescents in a Mesopic Visual Environment After Wearing Orthokeratology Lenses: A Prospective Study.

This study aimed to investigate changes in objective vision quality in mesopic environments in teenagers with myopia after wearing orthokeratology (OK) lenses. This prospective clinical study included 45 patients (80 eyes) who received OK lenses at the First Affiliated Hospital of Jinan University from March 2021 to September 2021. An Optical Path Difference-Scan III refractive power/corneal analyzer was used to determine the corneal topographic parameters (corneal e, corneal Q, surface asymmetry index (SAI), and surface regularity index (SRI)), higher-order aberrations (HOAs), axial length (AL) change, lens decentration, induced astigmatism, target power, and Strehl ratio (SR) in a mesopic visual environment after wearing OK lenses for 6 months. In addition, corneal morphological parameters, HOAs, and SR were analyzed in a mesopic visual environment. Finally, we investigated the correlations among corneal morphology, HOAs, AL change, lens decentration, induced astigmatism, and SR. The SAI value was significantly higher ( P <0.01), and the corneal e was significantly lower ( P <0.01), in a mesopic visual environment after wearing OK lenses for 1 week than baseline. A significant increase was observed in total HOAs and spherical aberrations, compared with before the OK lenses were worn ( P <0.01). In addition, SR in the mesopic visual environment decreased significantly after wearing the lenses ( P <0.01). No significant differences were observed ( P >0.05) among the 1-week, 1-month, 3-month, and 6-month follow-up findings. After 6 months, AL and lens decentration did not differ significantly compared with before ( P >0.05), whereas induced astigmatism significantly increased ( P <0.05). Negative correlations were observed between corneal Q, SAI, SRI, HOAs, induced astigmatism, and SR, and positive correlations were found between corneal e, AL change, lens decentration, and SR, after wearing OK lenses. • Wearing orthokeratology lenses significantly altered corneal morphology and HOAs in myopic teenagers within 1 week. • The changes that we observed in the eyes of adolescents with myopia after wearing orthokeratology lenses decreased vision quality in mesopic environments. • Strehl ratio is significantly correlated with multiple parameters, including HOAs, AL change, and lens decentration. In teenagers with myopia wearing OK lenses, significant changes in vision quality and corneal morphology were observed, leading to increased aberrations and affecting optical imaging quality. Furthermore, SR is significantly correlated with multiple parameters, including HOAs, AL change, and lens decentration. This study is registered with the United States Clinical Trials Registry under registration number NCT04929119.

Long-term effect of orthokeratology on controlling myopia progression in children with allergic conjunctivitis

BackgroundTo observe whether the effect of orthokeratology (OK) lenses on myopia control in children with allergic conjunctivitis (AC) after three years of wear differs from that in children without allergic conjunctivitis (nAC) and to identify the potential influencing factors. MethodsThis was a retrospective case–control study. Patients aged 8–15 years who were fitted with OK lenses in 2019 were collected. A three-year follow-up was also conducted, documenting all corneal adverse events (AEs) and the increase in axial length (AL) of the eye after three years of wearing OK lenses. Patients were divided into groups with and without AC based on their medical history and physical signs at the initial fitting. Baseline data and AL elongation after three years were compared between the two groups. ResultsA total of 309 patients were included in this study, with 47 in the AC group and 262 in the nAC group. There were no statistically significant differences between the two groups in terms of age, sex, spherical equivalent (SE), AL of the eye and environment. After three years of OK lens wear, the AL elongation in the AC group was 0.96 ± 0.45 mm, whereas it was 0.69 ± 0.45 mm in the nAC group (P < 0.001). The extent of AL elongation in AC patients was significantly greater than that in nAC patients. During the three-year follow-up period, the duration of OK lenses discontinuation due to corneal AEs in the AC group was greater than that in the nAC group (P < 0.05). ConclusionsThis study found that allergic conjunctivitis can affect the efficacy of OK lenses in controlling myopia after three years of treatment.

Analysis of Treatment Discontinuation in Orthokeratology: Studying Efficacy, Safety, and Patient Adherence Over Six Months.

This study aimed to evaluate the efficacy, safety, and participant compliance of orthokeratology treatment for the correction of myopic refractive errors over a six-month prospective study and to define the potential reasons for early treatment discontinuation. A total of 32 participants with low-to-moderate myopia were fitted with the spherical model of corneal refractive therapy (CRT) orthokeratology lenses (Paragon Vision Sciences) and followed over six months, with specific attention to alterations in refractive error, corneal topography, and epithelial thickness. Concurrently, participant feedback and reasons for any treatment discontinuation were documented. Significant changes in refractive error and in corneal topography were observed, with approximately 50% of the refractive error being corrected on the first night of use and 100% by the first two weeks ( P <0.001). Central epithelial thickness experienced substantial thinning, reducing to 15.65±4.49 μm (67.38%) ( P <0.001) after 6 months of lens use. Six participants withdrew from this study for varied reasons, including unmet visual expectations and difficulty adhering to the lens-wearing regimen. Notably, the dropout group exhibited higher baseline low-order aberrations and less prolate corneas than those who persisted with the treatment ( P <0.05). Orthokeratology with CRT is efficacious and safe for the correction of low-to-moderate myopia in adults, but a portion of patients discontinue the treatment in the first 6 months of contact lens wear. Special care should be taken when recommending orthokeratology in patients with higher levels of myopia and corneas with less prolate shape, providing more realistic expectations and even changing to dual axis or more sophisticated designs.

Efficacy and safety of 0.01% atropine combined with orthokeratology lens in delaying juvenile myopia: An observational study.

It aims to study the efficacy and safety of low-concentration Atropine combined with orthokeratology (OK) lens in delaying juvenile myopia. This is a prospective study, 172 adolescents aged 8 to 12 years who were admitted to the diopter department of Hengshui People Hospital from April 2021 to May 2022 were selected. According to the equivalent spherical diopter measured at the time of initial diagnosis, myopic patients were randomly divided into low myopia group (group A) and moderate myopia group (group B). At the same time, according to the different treatment methods, the patients were divided into the group wearing frame glasses alone (group c), the group wearing frame glasses with low-concentration Atropine (group d), the group wearing corneal shaping glasses alone at night (group e), and the group wearing corneal shaping glasses at night with low-concentration Atropine (group f). The control effect of myopia development and axial elongation in group f was better than that in groups d and e (P < .05). The effect of controlling myopia development and axial elongation in group f is with P > .05. The probability of postoperative adverse reactions in group f was lower and lower than that in the other groups. Low-concentration atropine combined with OK lens could effectively delay the development of juvenile myopia, and had a high safety. Low-concentration of Atropine would not have a significant impact on the basic tear secretion and tear film stability. Nightwear of OK lens also had no significant impact, but it would significantly reduce the tear film rupture time in the first 3 months, and at the same time, the tear film rupture time would be the same after 6 months as before treatment.

Optical coherence tomography angiography reveals macular microvascular changes in myopic adolescents following orthokeratology lens wear.

This study aimed to investigate the 6-month effects of wearing orthokeratology (OK) lenses on the retina vessel density (VD), vessel diameter index (VDI), and foveal avascular zone (FAZ) of myopia children using optical coherence tomography angiography, and to further investigate the underlying mechanisms of Orthokeratology in myopia control. Sixty-two eyes form 62 subjects were included in the study. Baseline and 6-month measurements of axial length (AL), anterior chamber depth (ACD), FAZ area, FAZ perimeter, FAZ circularity, vessel density (VD) and VDI from both the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were obtained. The mean age of the participants was 11.02 years (range: 8 years to 15 years), with 41.9% males and 58.1% females. Six months after orthokeratology, ACD decreased significantly, and AL remain unchanged. SCP-VD and DCP-VD significantly increased after treatment without obvious change of VDI, and FAZ parameters remained unchanged. During follow-up period, SCP-VD increased in all subgroups especially in mild myopia group, and DCP-VD increased significantly in all subgroups except for the group 8-10 years. After the 6-month treatment of orthokeratology in myopia children, the macular microvasculature changed significantly. We observed a significant increase of vessel densities in both SCP and DCP without obvious effect on vascular morphology. The changes of DCP-VD tended to be more sensitive in the elder subgroup, and the efficacy of orthokeratology might be greater in mild myopia group. OCT-A may provide additional information on myopia progression and the mechanisms of controlling myopia with OK lens treatment.

Effects of orthokeratology on corneal reshaping and the delaying of axial eye growth in children

PurposeTo investigate the inhibition of myopia progression and axial elongation in children wearing orthokeratology (OK) lenses, as well as to evaluate the status of corneal reshaping, this study explores the relationship between changes in central corneal curvature (K-value) and e-value induced by OK lenses and axial elongation. MethodsIn this study, it is planned to select children aged 8–15 who wear orthokeratology lenses at the Pediatric Ophthalmology and Strabismus Clinic of the Second Affiliated Hospital of Dalian Medical University. All children will undergo slit lamp examination, visual acuity assessment, computerized refraction, intraocular pressure measurement, biometry, and corneal topography examination before lens wear and at 1 month, 3 months, and 6 months after lens wear in the pediatric ophthalmology clinic. Based on age (lower age group (8 < age ≤12 years); higher age group (12 < age ≤15 years)) and baseline equivalent spherical (SE) value (mild myopia group (−1.00 D < SE ≤ −3.25D); moderate myopia group (−3.25 D < SE ≤ −6.00 D)), four groups will be formed by pairing these factors. Suitable data will be selected according to inclusion and exclusion criteria, and different groups will be included. Data will be organized, and statistical analysis will be performed using SPSS software to obtain the results. The expected results will be discussed and analyzed. ResultsAfter wearing OK lenses, all four groups achieved good visual acuity at follow-up. At 6 months, there were no significant differences in visual acuity among the four groups (P = 0.149, >0.05). There were no significant differences in refractive error among the four groups (P = 0.066, >0.05). Baseline axial length differed significantly among the four groups (P = 0.000, <0.001), with the LM group having longer axial length than the LL group (P < 0.001, paired samples t-test), and the HM group having longer axial length than the HL group (P < 0.001, paired samples t-test). However, there were no significant differences in axial length change compared to baseline among the groups at 1 month, 3 months, and 6 months (P1 = 0.053; P3 = 0.557; P6 = 0.329, >0.05). Significant differences were observed in corneal flat K-value change compared to baseline among the four groups at 1 month, 3 months, and 6 months (P1 = 0.001, P3 = 0.001, P6 = 0.004, <0.05). There were no significant differences in e-value change among the groups at 1 and 3 months (P1 = 0.205, P3 = 0.252, >0.05), but significant differences were found in e-value change compared to baseline at 6 months (P6 = 0.010, <0.05). Multiple regression analysis with changes in central corneal flat K-value and e-value as independent variables and axial elongation as the dependent variable showed a correlation between e-value change at 6 months and axial elongation (P = 0.004, <0.05), indicating a negative correlation. ConclusionOrthokeratology (OK) lenses effectively improve myopic children's vision by reshaping the cornea, leading to reduced central corneal curvature and flattening of its anterior surface. The effectiveness of OK lenses is not significantly affected by age or initial myopia severity. Children of varying ages and myopia levels experience similar levels of axial length control with OK lens wear. Changes in corneal shape due to OK lenses affect axial elongation, with greater changes in corneal morphology associated with smaller increases in axial length.

The Impact of Back Optic Zone Design in Orthokeratology on Visual Performance.

To evaluate the visual performance in adolescents undergoing orthokeratology (OrthoK) treatment with two different optical zone diameters (OZDs). This randomized, double-masked, self-controlled prospective study was conducted at Tianjin Eye Hospital (Tianjin, China) in June 2022. Thirty-six eligible schoolchildren were enrolled and fitted with corneal refractive therapy lenses with two sizes of OZDs (5 mm [5OZ] and 6 mm [6OZ]). Each participant was randomized to wear the 5OZ in one eye and the 6OZ in the contralateral eye. Subjective visual quality was assessed using visual acuity, refraction, contrast sensitivity function, and visual symptoms, and the objective optical quality was assessed using ocular higher order aberrations (HOAs) and modulation transfer function (MTF). Thirty-five myopic children completed a 1-month follow-up visit. The 5OZ lens induced significantly smaller treatment zone diameters than the 6OZ lens (P < 0.001). Subjective visual quality did not differ significantly between the two groups. Compared to baseline, aberrations of Z40, coma-like, spherical-like, and total HOAs in both groups increased significantly (P < 0.05). For the 3-mm pupils, spherical aberration in the 5OZ group was significantly higher than that in the 6OZ group (P < 0.05). The MTF value of the 6OZ group was significantly higher than that of 5OZ group for 0.3 and 1.5 cycles per degree for the 3-mm pupils (P = 0.006 and P = 0.026, respectively). However, HOAs or MTF did not differ significantly between the two groups for the 5-mm pupils. The difference induced by varying OZD was significant only in the smaller pupil condition. The selection of OZD in OrthoK designs in real-world patient management should be done while considering individual pupil size. This study revealed that the objective visual quality of small OZD lenses was only slightly affected for the small pupil size.

Artificial Intelligence-Assisted Prescription Determination for Orthokeratology Lens Fitting: From Algorithm to Clinical Practice.

To explore the potential of artificial intelligence (AI) to assist prescription determination for orthokeratology (OK) lenses. Artificial intelligence algorithm development followed by a real-world trial. A total of 11,502 OK lenses fitting records collected from seven clinical environments covering major brands. Records were randomly divided in a three-way data split. Cross-validation was used to identify the most accurate algorithm, followed by an evaluation using an independent test data set. An online AI-assisted system was implemented and assessed in a real-world trial involving four junior and three senior clinicians. The primary outcome measure was the algorithm's accuracy (ACC). The ACC of the best performance of algorithms to predict the targeted reduction amplitude, lens diameter, and alignment curve of the prescription was 0.80, 0.82, and 0.83, respectively. With the assistance of the AI system, the number of trials required to determine the final prescription significantly decreased for six of the seven participating clinicians (all P <0.01). This reduction was more significant among junior clinicians compared with consultants (0.76±0.60 vs. 0.32±0.60, P <0.001). Junior clinicians achieved clinical outcomes comparable to their seniors, as 93.96% (140/149) and 94.44% (119/126), respectively, of the eyes fitted achieved unaided visual acuity no worse than 0.8 ( P =0.864). AI can improve prescription efficiency and reduce discrepancies in clinical outcomes among clinicians with differing levels of experience. Embedment of AI in practice should ultimately help lessen the medical burden and improve service quality for myopia boom emerging worldwide.

Influence of back optic zone diameter on corneal morphology with orthokeratology lenses

ObjectiveThis study aimed to compare the changes in corneal morphological characteristics in corneal topography assessments performed after wearing orthokeratology (OK) lenses with different back optic zone diameters (BOZDs). These changes included the change ratios of the apical corneal power (ACP), the maximum relative corneal refractive power (mRCRP), and the treatment zone diameter (TZD). MethodsData from 133 children with myopia (average age 9.50 ± 1.23 years) treated at Fudan University Eye and Ear, Nose, and Throat Hospital were retrospectively analyzed. All participants wore the same brand of tangent-design OK lens (corneal refractive therapy, CRT). According to the BOZD, the patients were divided into two groups, of 5.0 and 6.0 mm BOZD, respectively. Corneal topography was analyzed at baseline, as well as 1 day, 1 week, and 1 month after wearing the lenses, and the change ratios of ACP, mRCRP, and TZD were compared between the two groups. ResultsThe change ratio of the ACP did not differ significantly between the BOZD 5.0 and 6.0 groups after 1 day or 1 week of lens wear (P = 0.170 and P = 0.113, respectively). However, after 1 month of lens wear, the change ratio of the ACP in the BOZD 5.0 group was significantly larger than that in the BOZD 6.0 group (P < 0.001). After 1 month of lens wear, the mRCRP along the horizontal and vertical meridians was higher (P < 0.05) and the TZD was significantly smaller (P < 0.001) in the BOZD 5.0 group than in the BOZD 6.0 group. ConclusionIn CRT OK lenses, a small BOZD lens can produce faster corneal shaping, a larger mRCRP, and a smaller TZD, which may have a better effect on slowing ocular axial length elongation. The lens parameters are also a factor affecting the TZD.

Effect of 0.01% atropine combined with orthokeratology lens on axial elongation: a 2-year randomized, double-masked, placebo-controlled, cross-over trial.

To evaluate the effect of 0.01% atropine combined with orthokeratology (OK) lens on axial elongation in schoolchildren with myopia. Sixty children aged 8-12 years with spherical equivalent refraction (SER) from -1.00D to -4.00D in both eyes were enrolled in this randomized, double-masked, placebo-controlled, cross-over trial. Children who had been wearing OK lenses for 2 months were randomly assigned into combination group (combination of OK lens and 0.01% atropine) for 1 year followed by control group (combination of OK lens and placebo) for another 1 year or vice versa. This trial was registered in the Chinese Clinical Trial Registry (Number: ChiCTR2000033904, 16/06/2020). The primary outcome was changes in axial length (AL). Data of right eyes were analyzed. There were statistically significant differences in the changes in AL between combination and control groups after generalized estimating equation model adjusting for age and baseline SER (p = 0.001). The mean axial elongation difference between combination and control groups was 0.10 mm in the first year (0.10 ± 0.13 mm vs. 0.20 ±0.15 mm; p = 0.01), and 0.09 mm in the second year (0.22 ± 0.10 mm vs. 0.13 ± 0.14 mm; p = 0.01), respectively. The mean axial elongation difference of two groups in the first year was similar to that in the second year during the cross-over treatment. In central Mainland China in myopic children, the treatment of combination therapy is more effective than single OK lens in controlling axial elongation.

The effect of the back optic zone diameter on the treatment zone area and axial elongation in orthokeratology.

To investigate the influence of corneal parameters on the treatment zone area (TZA) after Corneal Refractive Therapy (CRT) with a 5.0-mm back optical zone diameter (BOZD) were worn and to compare changes in the axial length (AL) with traditional 6.0-mm BOZD lenses. This retrospective study involved 146 subjects (7-12years) who wore orthokeratology (ortho-K) lenses for one year: 86 subjects were treated with CRT 5.0-mm lenses, and 60 subjects were treated with CRT 6.0-mm lenses. The TZA was measured after one year of ortho-K treatment. Both TZA and AL elongation after wearing the two kinds of lenses was compared. The parameters were recorded in the CRT 5.0 group: flat K, steep K, corneal toricity, e value, and anterior corneal elevation values at the 3-, 4-, and 5-mm chords along the principal meridians of the superior, inferior, nasal, and temporal sides. The relationships between these data and the TZA were analyzed. The TZA was 12.90±5.15mm2 and 20.61±4.54mm2, and the AL elongation was 0.15±0.18mm and 0.26±0.18mm in the CRT 5.0 group and the CRT 6.0 group, respectively (all p<0.001). The one-year AL elongation was significantly associated with initial age and the TZA (r=-0.394, 0.393; all p<0.001) in the CRT 5.0 group. The following corneal parameters were found to have statistically significant correlations with the TZA: the e value, difference in corneal elevation (nasal-temporal at the 3-, 4-, and 5-mm chord), and the absolute value of elevation difference (nasal-temporal at the 3- and 4-mm chord and inferior-superior at the 3-, 4-, and 5-mm chord). The e value was the only relevant factor for the TZA by multiple regression analysis (unstandardized β=14.219, p=0.008). In the CRT 6.0 group, the one-year AL elongation was statistically significantly associated only with initial age (r=-0.605, p=0.005), but not with the TZA (p=0.161). A smaller TZA induced by a smaller BOZD may be beneficial for retarding AL elongation in children undergoing ortho-K treatment. The morphology and eccentricity of the cornea may show effects on the TZA.