Optical Quality of the Cornea After Overnight Orthokeratology

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

PURPOSE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Advances in myopia control strategies for children

Myopia has long been a global threat to public health. Timely interventions are likely to reduce the risk of vision-threatening complications. There are both established and rapidly evolving therapeutic approaches to slow myopia progression and/or delay its onset. The effective methods for slowing myopia progression include atropine eye-drops, defocus incorporated multiple segments (DIMS) spectacle lenses, spectacle lenses with highly aspherical lenslets target (HALT), diffusion optics technology (DOT) spectacle lenses, red light therapy (RLT), multifocal soft contact lenses and orthokeratology. Among these, 0.05% atropine, HALT lenses, RLT and +3.00 peripheral addition soft contact lenses yield over 60% reduction in myopia progression, whereas DIMS, DOT and MiSight contact lenses demonstrate at least 50% myopia control efficacy. 0.05% atropine demonstrates a more optimal balance of efficacy and safety than 0.01%. The efficacy of 0.01% atropine has not been consistent and requires further validation across diverse ethnicities. Combining atropine 0.01% with orthokeratology or DIMS spectacles yields better outcomes than using these interventions as monotherapies. Increased outdoor time is an effective public health strategy for myopia prevention while recent studies suggest that 0.05% low-concentration atropine and RLT therapy have promising potential as clinical myopia prevention interventions for high-risk groups. Myopia control spectacle lenses, being the least invasive, are safe for long-term use. However, when considering other approaches, it is essential to ensure proper instruction and regular follow-ups to maintain safety and monitor any potential complications. Ultimately, significant advances have been made in myopia control strategies, many of which have shown meaningful clinical outcomes. However, regular use and adequate safety monitoring over extended durations are imperative to foster confidence that can only come from extensive clinical experience.

Characteristics of full compensation and its association with total astigmatism: A cross-sectional study

Objective

To evaluate the characteristics of full compensation and its association with the prevalence of total astigmatism (TA), and to analyze the effects of TA on uncorrected distance visual acuity (UDVA).

Methods

With random cluster sampling based on a school-based cross-sectional design, children aged 4 to 18 years were recruited in September 2020, Shandong Province, China. TA, anterior corneal astigmatism (ACA), and ocular residual astigmatism (ORA) were converted to vectorial components (J0, J45), followed by an assessment of the compensatory effect of ACA by ORA. Astigmatism was defined as a cylinder that was better than or equal to 0.75 diopters (D). Logistic regression analysis was used to assess the related factors for children with full compensation, and the generalized linear model was used to assess the influence of TA on UDVA.

Results

Out of 4,494 eligible children, data of 4,145 children (92.3%, 9.23 ± 3.15 years, 50.4% boys) were included in the statistical analysis. The prevalence of TA (27.9%) increased significantly with age (P_trend < 0.001). The distribution of full compensation in J0 and J45 components were similar (22.1% and 25.6%, respectively), which decreased with age (P_trend < 0.001). The closer the refractive status was to emmetropization, the higher the proportion of full compensation and the lower the prevalence of TA were. Shorter axial length (J0: Odds Ratio (OR) = 0.76, 95% confidence interval (CI): 0.61 to 0.94, P = 0.010), better UDVA (J0: OR = 0.37, 95% CI: 0.21 to 0.65, P < 0.001; J45: OR = 0.34, 95% CI: 0.20 to 0.59, P < 0.001), and longer average corneal curvature radius (J0: OR = 3.72, 95% CI: 2.18 to 6.34, P < 0.001; J45: OR = 2.82, 95% CI: 1.67 to 4.76, P < 0.001) were associated with full compensation. Higher TA was associated with a worse UDVA (β = 0.03, 95% CI: 0.02 to 0.04, P < 0.001).

Conclusions

The prevalence of TA gradually increased with age, and showed a U-shaped distribution with increased refraction. Full compensation was associated with smaller TA and better UDVA. This indicated that considering the compensatory effect of ORA is vital for astigmatism correction in clinical work, which may improve the visual quality.

Myopia Control With Orthokeratology: A Review

ABSTRACT

A number of studies regarding the effect of orthokeratology (OK) on myopia progression have been published and shown that it can slow myopia progression in school-aged children. Recently, OK has been considered to be one of the most effective optical treatments for myopia control. This article reviewed the peer-reviewed literature on the efficacy of OK for myopia control. Although it cannot halt myopia progression completely, the inhibitory effect on axial elongation for 2 years has been reported to be from 32% to 63%, as compared with single-vision spectacles and contact lenses. In addition, the efficacy and acceptable safety have been confirmed even in several long-term studies up to 10 years. However, the possibility of a rebound phenomenon in myopia progression after OK discontinuation remains unknown. It is also unclear how long the treatment should be continued to attain the maximum benefit in each patient. In the near future, further research including assessment of rebound phenomenon should be conducted with longer follow-up periods in more diverse populations.

Thickness profiles of the corneal epithelium along the steep and flat meridians of astigmatic corneas after orthokeratology

Background

The aim of this study was to investigate the changes in corneal epithelial thickness along the principle meridians of astigmatic corneas after six months of overnight spherical myopic orthokeratology (OK) lens wear.

Methods

This is a prospective study. Fifty-seven subjects with up to 1.50 diopters (D) of corneal toricity wore spherical OK lenses for 6 months. Evaluations of OK lens fit, visual acuity, refractions and corneal toricity (CT) were performed. Fourier-domain optical coherence tomography (FD-OCT) was conducted to measure the corneal epithelial thickness (ET) along the principle meridians of corneal toricity over a diameter of 6 mm. The means of △ET of the same diameter at individual meridians (△ETSm and △ETFm) were calculated and compared.

Results

Visual acuity and refraction improved significantly after OK lens wear. △ETFm thinned more than △ETSm (P = 0.027) at 1.5 mm in radius. △ETSm thickened more than △ETFm at 2.5 mm (P = 0.019) and 3.0 mm (P = 0.036).∣△ETSm - △ETFm∣ were significantly correlated with the baseline central CT at 2.0 mm, 2.5 mm and 3.0 mm. ∣△ETSm - △ETFm∣was significantly correlated with the baseline peripheral CT at 2.5 mm.

Conclusions

Overnight wear of spherical OK lenses resulted in differential changes in the thickness profiles of the corneal epithelium between the steep and flat meridians in eyes with corneal toricity.

The Topographical Effect of Optical Zone Diameter in Orthokeratology Contact Lenses in High Myopes

Purpose

To evaluate the effect of the optical zone diameter (OZ) in orthokeratology contact lenses regarding the topographical profile in patients with high myopia (−4.00 D to −7.00 D) and to study its effect over the visual quality.

Materials and Methods

Twelve patients (18 eyes) were fitted with overnight orthokeratology (OrthoK) with a randomized 6 mm or 5 mm OZ lens worn for 2 weeks, followed by a 2-week washout period, between both designs. Keratometry (K) readings, optical zone treatment diameter (OZT), peripheral ring width (PRW), higher-order aberrations (HOA), high (HC) and low contrast (LC) visual acuity, and subjective vision and comfort were measured at baseline and after 2 weeks of OrthoK lens wear of each contact lens.

Results

No significant differences were found between any measurements for the same subject at both baselines (p value > 0.05). There was no difference between OZ lens designs found in refraction, subjective vision or comfort, and HC and LC visual acuity. Contrast sensitivity was decreased in the 5 mm OZ lens design compared with 6 mm OZ design (p-value < 0.05). 5 mm OZ design provoked a greater flattening, more powerful midperipheral ring and 4^th-order corneal and total spherical aberration than the 6 mm OZ design, being statistically significant after 7 days, for corneal aberration, and 15 days, for corneal and total, of wearing the lens (p-value < 0.05). The OZT obtained were 2.8 ± 0.2 mm and 3.1 ± 0.1 mm for 5 mm and 6 mm OZ design, respectively (p-value < 0.05). Regarding PRW, the 5 mm OZ design had a wider ring width in both the nasal and temporal zones (p-value < 0.05).

Conclusions

A smaller diameter optical zone (5 mm) in orthokeratology lenses produces a smaller treatment area and a larger and more powerful midperipheral ring, increasing the 4^th-order spherical aberration that affects only the contrast sensitivity but without differences in visual acuity and subjective vision compared with a larger OZ diameter (6 mm).

Influence of overnight orthokeratology lens fitting decentration on corneal topography reshaping

Background

This retrospective study was designed to investigate the sole influence of orthokeratology (OK) lens fitting decentration on the Zernike coefficients of the reshaped anterior corneal surface.

Methods

This study comprised a review of 106 right eyes and measurements of corneal topography both before OK and at 1-month follow-up visit. A routine was designed to calculate local corneal surface astigmatism and assist the determination of OK lens fitting decentration from pupil center. The pupil-centered corneal Zernike coefficients of baseline (PCCB) and post-treatment (PCCP) were calculated. Meanwhile, the OK-lens-centered corneal Zernike coefficients of post-treatment (OCCP) were also calculated and considered as the presumptive ideal fitting group without decentration. Relationships between lens fitting decentration and the change of Zernike coefficients including (PCCP − PCCB) and (PCCP − OCCP) were analyzed.

Results

Patients with a mean age of 11 ± 2.36 years old had an average spherical equivalent refractive error of −3.52 ± 1.06 D before OK. One month after treatment, OK lens fitting decentration from pupil center was 0.68 ± 0.35 mm. RMS of 3rd-order (P < 0.05), RMS of 4th-order (P < 0.001) and RMS of total high order (P < 0.001) corneal Zernike coefficients were increased in PCCP by comparing with OCCP, which was solely caused by lens fitting decentration. Nevertheless, no significant difference was observed in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_2^0 $$\end{document}C20 (P > 0.05). For the high order corneal Zernike coefficients in (PCCP – OCCP), radial distance of decentration was correlated with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_3^{-1} $$\end{document}C3−1 (r = −0.296, P < 0.05), \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_3^1 $$\end{document}C31 (r = −0.396, P < 0.001), and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_4^0 $$\end{document}C40 (r = 0.449, P < 0.001), horizontal decentration was significantly correlated with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_3^1 $$\end{document}C31 (r = 0.901, P < 0.001) and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_5^1 $$\end{document}C51 (r = 0.340, P < 0.001), and vertical decentration was significantly correlated with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_3^{-1} $$\end{document}C3−1 (r = 0.904, P < 0.001).

Conclusions

OK lens fitting decentration within 1.5 mm hardly influenced the change of corneal spherical power for myopia correction, but significantly induced additional corneal high order Zernike coefficients including \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_3^{-1} $$\end{document}C3−1, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_3^1 $$\end{document}C31, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_4^0 $$\end{document}C40, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {C}_5^1 $$\end{document}C51.

Changes in refraction, ocular aberrations, and corneal structure after suspending rigid gas-permeable contact lens wear in keratoconus

PURPOSE

This study reports on changes in visual acuity, ocular higher-order aberrations, and refraction after suspending rigid gas-permeable lens wear for 1 week in 15 patients with moderate to severe keratoconus. Alterations in the anterior surface, central corneal powers and axes, and central corneal thickness were also explored.

METHODS

Scheimpflug photography and Hartmann-Shack aberrometry were performed at 2 visits, 7 days apart, after the patients had removed their habitual contact lenses. Subjective refraction and both high- and low-contrast logarithm of the minimum angle of resolution visual acuities were also recorded at both visits.

RESULTS

Reductions in both high-contrast visual acuity (P = 0.001) and low-contrast visual acuity (P = 0.002), along with an increase in third-order root mean square aberrations (P = 0.008), occurred after rigid gas-permeable lens wear was suspended in these patients with keratoconus. However, no significant changes in subjective refraction were found over the 1-week period (P ≥ 0.10). Significant correlations were observed between third-order coma root mean square aberrations and the measured high-contrast (r(p) ≥ 0.59; P ≤ 0.02) and low-contrast visual acuities (r(P) ≥ 0.61; P ≤ 0.015). In addition to increases in the anterior surface central corneal powers (P ≤ 0.02), a reduction in central corneal thickness also was found between the 2 visits (P = 0.00016).

CONCLUSIONS

Changes in the optical and structural parameters of the keratoconic cornea occur after suspending rigid gas-permeable contact lens wear. This information may be of interest to practitioners concerned with prescribing aberration-controlling soft contact lenses for such patients.

Straylight and contrast sensitivity after corneal refractive therapy

PURPOSE

To compare intraocular straylight and contrast sensitivity determined before corneal refractive therapy and after 15 days and 1 month of treatment.

METHODS

A single-center, prospective, and longitudinal study was performed in 30 subjects undergoing corneal refractive therapy. In each subject, high-contrast visual acuity (HCVA), low-contrast visual acuity (LCVA), straylight, and contrast sensitivity were determined at baseline and after 15 days and 1 month after the treatment. Straylight was measured using the van den Berg straylight meter (third generation). Contrast sensitivity was determined under both photopic and mesopic conditions using the VCTS 6500 instrument (Vision Contrast Test System). EDTRS charts (logMAR units) were used to measure HCVA and LCVA.

RESULTS

Straylight (mean ± standard deviation) significantly fell from baseline (0.94 ± 0.14) to the values recorded at 1 month (0.85 ± 0.11, p = 0.009). Photopic contrast sensitivity remained stable yet mesopic contrast sensitivity measured at high spatial frequencies was significantly reduced. No correlations between intraocular straylight and contrast sensitivity, HCVA, or LCVA were observed 15 days and 1 month after corneal refractive therapy.

CONCLUSIONS

Our findings suggest improved intraocular straylight readings 1 month after starting the treatment, although the changes observed in straylight could not be related to changes in mesopic and photopic contrast sensitivity or HCVA and LCVA. Mesopic contrast sensitivity was more affected by the treatment intervention than photopic contrast sensitivity.

Short-term effects of overnight orthokeratology on corneal cell morphology and corneal thickness

PURPOSE

To examine the morphological and biometric corneal changes produced over periods of 15 days and 1 month after overnight orthokeratology (OK).

METHODS

Prospective, single-center, longitudinal trial. Twenty-seven right eyes of 27 subjects (group 1) with low to moderate myopia wore OK lenses for 1 month. Ten right eyes of 10 subjects (group 2) with emmetropia to low myopia who did not wear any type of contact lens served as controls. Corneal morphometric measurements were obtained in vivo using a confocal microscope to examine the central and midperipheral cornea. Thickness measurements in the peripheral cornea were obtained by optical coherence tomography. Changes in visual acuity, refractive error, and corneal topography were also analyzed.

RESULTS

No significant changes in either endothelial cell or stromal cell density were observed after 1 month of OK. Basal epithelial cells were, however, significantly reduced (P < 0.01), and epithelial wing and superficial cells showed enhanced visibility (P < 0.05). Superficial cells increased in height and width, the width increase after 1 month being significant (P < 0.01). Epithelial thickness was significantly reduced in the central cornea and 2 mm around the center. Corneal pachymetry increased significantly in the band from 5 to 10 mm from the corneal apex (P < 0.01).

CONCLUSIONS

OK lenses for myopia induce significant structural and optical changes particularly in the central epithelium after 15 days or 1 month of wear. The central corneal epithelium responds to OK wear by undergoing significant epithelial cell shape and size alterations with no effects, however, on the cells of the corneal endothelium or the corneal stroma. Peripheral corneal thickness increased with respect to baseline values. These findings suggest that the corneal epithelium is the principal structure affected by the mechanical forces exerted by the OK lenses.

Changes in higher order wavefront aberrations after contact lens corneal refractive therapy and LASIK surgery

PURPOSE

To compare ocular higher order aberrations induced by corneal refractive therapy (CRT, Paragon Vision) to those produced by LASIK for patients with comparable levels of myopia.

METHODS

A retrospective chart review of 11 patients who used CRT lenses and 12 patients who underwent LASIK for correction of low to moderate myopia was performed. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and optical higher order aberrations were recorded before and 1 month after treatment for each patient.

RESULTS

The CRT group consisted of 11 patients (4 men, 7 women) with a mean age of 29.1+/-5.2 years (range: 23 to 40 years), and the LASIK group consisted of 12 patients (3 men, 9 women) with a mean age of 39.2+/-12.0 years (range: 23 to 60 years). Manifest refraction decreased statistically significantly from -2.81+/-1.05 diopters (D) at baseline to -0.77+/-0.64 D following CRT treatment at 1 month (P<.0001) and from -3.11+/-1.21 D at baseline to -0.43+/-0.27 D at 1 month after LASIK (P<.0001). Both CRT and LASIK exhibited no significant changes in total higher order aberrations for 4-mm pupils but induced statistically significant increases in total higher order aberrations for 6-mm pupils. Corneal refractive therapy and LASIK both exhibited statistically similar factors of change for total higher order aberrations and coma-like higher order aberrations for 6-mm pupils. Corneal refractive therapy demonstrated a statistically significant greater factor of increase in spherical-like higher order aberrations for 6-mm pupils (P=.01).

CONCLUSIONS

Contact lens corneal refractive therapy and LASIK can effectively correct myopia, but both increase higher order aberrations for 6-mm pupils to a similar degree. However, spherical-like aberrations were statistically significantly greater after CRT than after LASIK.

Influence of induced decentered orthokeratology lens on ocular higher-order wavefront aberrations and contrast sensitivity function

PURPOSE

To quantitatively evaluate the effect of overnight orthokeratology lenses intentionally left decentered after 3 months of wear and assess the influence on clinical outcomes such as ocular higher-order wavefront aberrations and contrast sensitivity function.

SETTING

Department of Ophthalmology, Tsukuba University Hospital, Ibaraki, Japan.

METHODS

This prospective study assessed refraction, visual acuity, corneal topography, wavefront aberration, and contrast sensitivity function before and 3 months after overnight orthokeratology treatment. Decentration of the treatment zone from the center of the entrance pupil was determined using computerized videokeratography (TMS-4) and data-analysis software (MatLab). The relationship between decentration and the clinical parameters was analyzed.

RESULTS

The mean age of the 23 patients (46 eyes) was 24.2 years+/-3.3 (SD) and the mean spherical equivalent refraction before treatment, -2.38+/-0.98 diopters. The mean magnitude of decentration (0.85+/-0.51 mm) was statistically significantly correlated with the amount of myopic correction (P<.05), increases in coma-like aberration (P<.01), increases in spherical-like aberration (P<.01), and reductions in contrast sensitivity function (P<.0001). Changes in contrast sensitivity function were also statistically significantly correlated with the amount of myopic correction (P<.05), changes in coma-like aberration (P<.01), and changes in spherical-like aberration (P<.01). Stepwise multiple regression analysis showed that the magnitude of decentration was the only explanatory variable related to contrast sensitivity function (P<.0001).

CONCLUSION

Decentered treatment of orthokeratology resulted in decreased contrast sensitivity after treatment, showing that centration of the procedure is crucial to good outcomes.

Epithelial, stromal, and corneal pachymetry changes during orthokeratology

PURPOSE

To describe epithelial, stromal, and corneal thickness profile changes induced by orthokeratology treatment.

METHODS

This is a case report of a mild myopic patient (OD -3.25/-0.50 x 172 and OS -3.25/-0.50 x 45) treated with orthokeratology lenses. The patient was assessed before treatment (following 2 weeks of no orthokeratology contact lens wear) and during treatment (after 30 consecutive nights of wearing orthokeratology lenses). Epithelial, stromal, and corneal thickness profile in vivo was measured by Artemis very high-frequency digital ultrasound scanning across the central 10 mm diameter of the cornea before and during orthokeratology treatment. Manifest refraction, contrast sensitivity, corneal topography, and corneal front surface aberrations were also measured before and during orthokeratology treatment. Thickness changes were correlated with corneal topography changes and corneal front surface aberrations changes. The effects of these changes on the patient's quality of vision were measured with manifest refraction and contrast sensitivity.

RESULTS

Orthokeratology lenses effectively corrected the patient's myopic refraction. Corneal topography demonstrated typical central flattening and an annulus of mid-peripheral steepening in both the eyes. The epithelial thickness profile was altered, with up to 18 microm of central epithelial thinning and up to 16 microm of annular mid-peripheral epithelial thickening. There also appeared to be a degree of stromal changes, with central stromal thickening and mid-peripheral stromal thinning, in particular in the left eye. There was a large increase in higher order aberrations, in particular in the left eye. This was associated with a decrease in contrast sensitivity in both the eyes.

CONCLUSIONS

Refractive changes during orthokeratology treatment are mainly induced by changes in epithelial thickness profile, while stromal changes may also contribute to a small extent.

Long-term clinical outcomes for overnight corneal reshaping in children and adults

PURPOSE

To retrospectively evaluate outcomes of overnight corneal reshaping (OCR) in children aged 12 years or younger compared to children older than 12 years and adults at one practice to establish the efficacy and safety of OCR during a period of 51 months.

METHODS

Examination records of OCR patients were reviewed for pretreatment data, including manifest refraction, keratometric readings, topography, corneal staining, and age at beginning OCR. Posttreatment records were reviewed for manifest refraction, unaided visual acuity, keratometric readings, topography, corneal staining, adverse events, and duration of OCR lens wear.

RESULTS

Records of 296 OCR patients were evaluated. One hundred fifty-four (52.0%) patients were 12 years old or younger. Sixty-eight percent of all patients in the study were Asian, and almost 95% of the patients aged 12 years or younger were Asian. The patients aged 12 years or younger had a mean original spherical equivalent refractive error of -3.50 +/- 1.50 diopters (D). The patients older than 12 years had a mean original spherical equivalent refractive error of -3.20 +/- 1.50 D. Refractive changes were similar between the group aged 12 years or younger and the group older than 12 years (3.30 +/- 1.40 D vs. 3.10 +/- 1.40 D) (P=0.14). The mean unaided, binocular logMAR visual acuity was 0.03 +/- 0.06 (i.e., 20/20) for the group aged 12 years or younger and 0.02 +/- 0.07 (i.e., 20/20) for the group older than 12 years. There were three adverse events during the study that did not result in a loss of best-corrected visual acuity. A total of 507 patient-years of wear was represented in the study.

CONCLUSIONS

OCR resulted in comparable safety and efficacy in temporarily reducing myopia for children younger than 12 years as it is for children older than 12 years and adults.