Correction Of Myopia Evaluation Trial Research Articles

Axial Elongation in Myopic Children and its Association With Myopia Progression in the Correction of Myopia Evaluation Trial

Describe axial elongation using 14-year longitudinal data in a large, ethnically diverse group of myopic children, estimate age and axial length (AL) at stabilization, and evaluate associations between the progression and stabilization of AL and myopia. Axial length was measured by A-scan ultrasonography annually. Axial length data were fit with individual polynomial functions and curve-based parameters (AL at stabilization and age at stabilization when annual rate of axial elongation ≤0.06 mm) were estimated. For myopia progression, noncycloplegic spherical equivalent refractions were fit with Gompertz functions. Four hundred thirty-one participants, with AL and myopia data fit successfully, were classified into four cohorts: Younger (n=30); Older (n=334); AL Stabilized at Baseline (n=19); and AL Not Stabilized (n=48). At AL stabilization, for participants in the Younger and Older Cohorts, mean (SD) age and AL were 16.3 (2.4) years and 25.2 (0.9) mm, respectively. No associations were found between age at AL stabilization and ethnicity, sex, or number of myopic parents. At stabilization, sex and number of myopic parents (both P<0.003), but not ethnicity, were significantly associated with AL. Axial length and myopia progression curves were highly correlated overall (all r>0.77, P<0.0001). However, unlike AL, the amount of myopia did not differ significantly between males and females. In most of the participants, AL increased rapidly at younger ages and then slowed and stabilized. The close association between growth and stabilization of AL and myopia is consistent with the suggestion that axial elongation is the primary ocular component in myopia progression and stabilization.

Longitudinal changes in corneal curvature and its relationship to axial length in the Correction of Myopia Evaluation Trial (COMET) cohort

PurposeTo describe longitudinal changes in corneal curvature (CC) and axial length (AL) over 14 years, and to explore the relationship between AL and CC, and the axial length/corneal radius (AL/CR) ratio. MethodsIn total 469, 6 to <12-year-old, children were enrolled in COMET. Measurements of refractive error, CC (D), CR (mm), and ocular component dimensions including AL were gathered annually. Linear mixed models were used to evaluate longitudinal changes adjusting for covariates (gender, ethnicity, lens type, baseline age and baseline refraction). The Pearson correlation coefficient between AL and CC was computed at each visit. ResultsThere was a slight but significant (p<0.0001) flattening in CC over 14 years. At all visits females had significantly steeper CC than males (overall difference=0.53D, p<0.0001). Caucasians had the steepest CC, and Hispanics the flattest (p=0.001). The correlation between AL and CC was −0.70 (p<0.0001) at baseline (mean age=9.3 years) and decreased to −0.53 (p<0.0001) at the 14-year visit (mean age=24.1 years). The average AL/CR ratio was 3.15 at baseline and increased to 3.31 at the 14-year visit. The correlation between the magnitude of myopia and AL/CR ratio was significantly higher (p<0.0001) at each visit than the correlation between myopia and AL alone. ConclusionsDifferences in average corneal curvature by age, gender, and ethnicity observed in early childhood remain consistent as myopia progresses and stabilizes. This study also demonstrates increases in the AL/CR ratio as myopia progresses and then stabilizes, supporting observations from previous cross-sectional data.

Longitudinal Changes in Lens Thickness in Myopic Children Enrolled in the Correction of Myopia Evaluation Trial (COMET)

ABSTRACTPurpose: To describe longitudinal changes in lens thickness in myopic children in the Correction of Myopia Evaluation Trial (COMET) and to investigate the association between these changes and myopia progression.Methods: Four-hundred sixty-nine 6 to <12-year-old children with −1.25 to −4.50 D of myopia were enrolled in COMET, a clinical trial comparing single vision lenses (SVLs) versus progressive addition lenses (PALs) for slowing myopia. Children remained in their original lenses for 5 years and then could wear contact lenses, SVLs or PALs. Myopia by cycloplegic autorefraction (Nidek ARK 700A) and ocular components, including lens thickness, by A-scan ultrasound (Sonomed A2500) were measured annually over 11 years. Analyses of lens thickness were based on right eye data from 426 children with refractions fit with Gompertz functions. Longitudinal lens thickness measurements for each participant were fit with a third-degree polynomial function, and average polynomial functions were calculated for three groups of children previously identified based on Gompertz functions: 6–7 years at baseline (n = 40), ≥8 years with progressing myopia (n = 329), and ≥8 years with non-progressing myopia (n = 56). ANOVAs were used for comparing the lens curve-based parameters among the three groups. Associations between lens and Gompertz parameters were assessed using Pearson correlations.Results: Overall, between 6 and 18 years the lenses thinned and then thickened, with the minimum value of 3.37 ± 0.15mm reached at 11.56 ± 2.04 years. The minimum lens thickness did not differ among the three myopia groups (p = 0.09), nor was it correlated with the amount of myopia at lens minimum or amount of final myopia (r’s = −0.01 and −0.03, respectively, p’s > 0.05).Conclusion: As a similar pattern of change in lens thickness with age was found in all children, whether their myopia progressed or not, these results suggest that the association of lens thinning and thickening with the course of myopia is coincidental rather than causal.

Choroidal Thickness Profiles in Myopic Eyes of Young Adults in the Correction of Myopia Evaluation Trial Cohort

To examine the relationship of choroidal thickness with axial length (AL) and myopia in young adult eyes in the ethnically diverse Correction of Myopia Evaluation Trial (COMET) cohort. Cross-sectional, multicenter study. In addition to measures of myopia by cycloplegic autorefraction and AL by A-scan ultrasonography, participants underwent optical coherence tomography imaging of the choroid in both eyes at their last visit (14 years after baseline). Using digital calipers, 2 independent readers measured choroidal thickness in the right eye (left eye if poor quality; n = 37) at 7 locations: fovea and 750, 1500, and 2250 μm nasal (N) and temporal (T) to the fovea. Choroidal thickness measurements were available from 294 of 346 (85%) imaged participants (mean age: 24.3 ± 1.4 years; 44.9% male) with mean myopia of -5.3 ± 2.0 diopters and mean AL of 25.5 ± 1.0 mm. Overall, choroidal thickness varied by location (P < .0001) and was thickest at the fovea (273.8 ± 70.9 μm) and thinnest nasally (N2250, 191.5 ± 69.3 μm). Multivariable analyses showed significantly thinner choroids in eyes with more myopia and longer AL at all locations except T2250 (P ≤ .001) and presence of peripapillary crescent at all locations except T1500 and T2250 (P ≤ .0001). Choroidal thickness varied by ethnicity at N2250 (P < .0001), with Asians having the thinnest and African Americans the thickest choroids. Choroids are thinner in longer, more myopic young adult eyes. The thinning was most prominent nasally and in eyes with a crescent. In the furthest nasal location, ethnicity was associated with choroidal thickness. The findings suggest that choroidal thickness should be evaluated, especially in the nasal regions where myopic degenerations are most commonly seen clinically.

Limited Change in Anisometropia and Aniso-Axial Length Over 13 Years in Myopic Children Enrolled in the Correction of Myopia Evaluation Trial

We investigated changes in anisometropia and aniso-axial length with myopia progression in the Correction of Myopia Evaluation Trial (COMET) cohort. Of 469 myopic children, 6 to <12 years old, enrolled in COMET, 358 were followed for 13 years. Cycloplegic autorefraction and axial length (AL) in each eye were measured annually. The COMET eligibility required anisometropia (interocular difference in spherical equivalent refraction) of ≤ 1.00 diopter (D). For each child, a linear regression line was fit to anisometropia data by visit, and the regression slope b was used as the rate of change. Logistic regression was applied to identify factors for significant changes in anisometropia (b ≥ 0.05 D/y, or a cumulative increase in anisometropia ≥ 0.50 D over 10 years). Similar analyses were applied to aniso-AL. A total of 358/469 (76.3%) children had refractions at baseline and the 13-year visit. The mean (SD) amount of anisometropia increased from 0.24 D (0.22 D) at baseline to 0.49 D (0.46 D) at the 13-year visit. A total of 319/358 (89.1%) had slopes |b| < 0.05 D/y and 39 (10.9%) had slopes |b| ≥ 0.05 D/y, with only one negative slope. Similarly, 334/358 (93.3%) children had little change in aniso-AL over time. The correlation between changes in anisometropia and aniso-AL over 13 years was 0.39 (P < 0.001). The correlation between changes in anisometropia and myopia progression was significant (r = -0.36, P < 0.001). No correlation was found between baseline anisometropia and myopia progression (r = -0.02, P = 0.68). Myopia and axial length progressed at a similar rate in both eyes for most children in COMET during the period of fast progression and eventual stabilization. These results may be more generalizable to school-aged myopic children with limited anisometropia at baseline. (ClinicalTrials.gov number, NCT00000113.).

Seasonal Variations in the Progression of Myopia in Children Enrolled in the Correction of Myopia Evaluation Trial

To investigate monthly and seasonal variations in the progression of myopia in children enrolled in the Correction of Myopia Evaluation Trial (COMET). An ethnically diverse cohort of 469 myopic 6- to <12 year-old children was randomized to single vision or progressive addition lenses and followed for 3 years with 98.5% retention. Progression of myopia was measured semiannually by noncycloplegic autorefraction (Nidek ARK 700A) and annually by cycloplegic autorefraction, with the former measurements used in these analyses. The semiannual progression rate was calculated as (change in spherical equivalent refraction between two consecutive semiannual visits/number of days between the two visits) times 182.5. Months were categorized as the midpoint between two visit dates. Seasons were classified as winter (October through March) or summer (April through September). The seasonal difference was tested using a linear mixed model adjusting for demographic variables (age, sex, ethnicity), baseline refraction, and treatment group. Data from 358 children (mean [± SD] age = 9.84 ± 1.27 years; mean myopia = -2.54 ± 0.84 diopters [D]) met the criteria for these analyses. Myopia progression varied systematically by month; it was slower in April through September than in the other months. Mean progression in winter was -0.35 ± 0.34 D and in summer was -0.14 ± 0.32 D, a statistically significant difference (0.21 D, P < 0.0001). The same seasonal pattern was found by age, sex, ethnicity (except in the small sample of Asians), lens type, and clinical center. The slower progression of myopia found in summer is likely related to children's spending more time outdoors and fewer hours in school. The data have clinical implications regarding the time of year and the frequency with which myopic children have eye examinations and the need for precise timing of visits in clinical trials testing new myopia treatments. (ClinicalTrials.gov number, NCT00000113.).

Visual activity and its association with myopia stabilisation

To evaluate the association between outdoor and nearwork activities at baseline and myopia stabilisation by age 15 in the Correction of Myopia Evaluation Trial (COMET). Correction of Myopia Evaluation Trial enrolled 469 children (ages: 6-11years) with spherical equivalent myopia between -1.25 and -4.50D, who were randomised to progressive addition or single vision lenses and followed for 5years in their original lenses. At baseline, families recorded the child's outdoor and nearwork activities for 3days within a week. Weekly hours spent in nearwork and outdoor activities were calculated for each participant. Refractions collected over 11years were fit using the Gompertz function to determine each participant's myopia stabilisation age. Myopia for each child was then categorized as stable/not stable by age 15. Half (233/469) of participants had usable baseline activity diaries and refraction data that could be fit with the Gompertz function, 59.7% (139/233) had stable myopia by age 15 and 40.3% had myopia that was not yet stable. The frequency of stable myopia was similar for the two categories (median split) of outdoor activities: 60% (71/118) for ≤9.0hours/week(-1) and 59% (68/115) for >9.0hours/week(-1) . 56% (64/114) of children reporting >21.0h of baseline weekly nearwork activity had stable myopia by age 15 compared to 63% (75/119) with ≤21.0h of near work (adjusted OR=0.74; 95% CI: 0.43-1.29). Using baseline nearwork as a continuous variable, the multivariable odds ratio for the association between baseline nearwork hours and stabilisation by age 15 is 0.98: 95% CI: 0.96-1.00, a result trending towards significance. While time spent in outdoor activities in childhood does not appear to be related to myopia stabilisation by age 15, less near work activity might potentially be associated with myopia stabilisation by that age.

Myopia Stabilization and Associated Factors Among Participants in the Correction of Myopia Evaluation Trial (COMET)

To use the Gompertz function to estimate the age and the amount of myopia at stabilization and to evaluate associated factors in the Correction of Myopia Evaluation Trial (COMET) cohort, a large ethnically diverse group of myopic children. The COMET enrolled 469 ethnically diverse children aged 6 to younger than 12 years with spherical equivalent refraction between -1.25 and -4.50 diopters (D). Noncycloplegic refraction was measured semiannually for 4 years and annually thereafter. Right eye data were fit to individual Gompertz functions in participants with at least 6 years of follow-up and at least seven refraction measurements over 11 years. Function parameters were estimated using a nonlinear least squares procedure. Associated factors were evaluated using linear regression. In total, 426 participants (91%) had valid Gompertz curve fits. The mean (SD) age at myopia stabilization was 15.61 (4.17) years, and the mean (SD) amount of myopia at stabilization was -4.87 (2.01) D. Ethnicity (P < 0.0001) but not sex or the number of myopic parents was associated with the age at stabilization. Ethnicity (P = 0.02) and the number of myopic parents (P = 0.01) but not sex were associated with myopia magnitude at stabilization. At stabilization, African Americans were youngest (mean age, 13.82 years) and had the least myopia (mean, -4.36 D). Participants with two versus no myopic parents had approximately 1.00 D more myopia at stabilization. The age and the amount of myopia at stabilization were correlated (r = -0.60, P < 0.0001). The Gompertz function provides estimates of the age and the amount of myopia at stabilization in an ethnically diverse cohort. These findings should provide guidance on the time course of myopia and on decisions regarding the type and timing of interventions.

Myopia, contact lens use and self‐esteem

To evaluate whether contact lens (CL) use was associated with self-esteem in myopic children originally enrolled in the Correction of Myopia Evaluation Trial (COMET), that after 5years continued as an observational study of myopia progression with CL use permitted. Usable data at the 6-year visit, one year after CL use was allowed (n=423/469, age 12-17years), included questions on CL use, refractive error measurements and self-reported self-esteem in several areas (scholastic/athletic competence, physical appearance, social acceptance, behavioural conduct and global self-worth). Self-esteem, scored from 1 (low) to 4 (high), was measured by the Self-Perception Profile for Children in participants under 14years or the Self-Perception Profile for Adolescents, in those 14years and older. Multiple regression analyses were used to evaluate associations between self-esteem and relevant factors identified by univariate analyses (e.g., CL use, gender, ethnicity), while adjusting for baseline self-esteem prior to CL use. Mean (±S.D.) self-esteem scores at the 6-year visit (mean age=15.3±1.3years; mean refractive error=-4.6±1.5D) ranged from 2.74 (± 0.76) on athletic competence to 3.33 (± 0.53) on global self-worth. CL wearers (n=224) compared to eyeglass wearers (n=199) were more likely to be female (p<0.0001). Those who chose to wear CLs had higher social acceptance, athletic competence and behavioural conduct scores (p<0.05) at baseline compared to eyeglass users. CL users continued to report higher social acceptance scores at the 6-year visit (p=0.03), after adjusting for baseline scores and other covariates. Ethnicity was also independently associated with social acceptance in the multivariable analyses (p=0.011); African-Americans had higher scores than Asians, Whites and Hispanics. Age and refractive error were not associated with self-esteem or CL use. COMET participants who chose to wear CLs after 5years of eyeglass use had higher self-esteem compared to those who remained in glasses both preceding and following CL use. This suggests that self-esteem may influence the decision to wear CLs and that CLs in turn are associated with higher self-esteem in individuals most likely to wear them.

Intraocular Pressure and Central Corneal Thickness in the COMET Cohort

To describe intraocular pressure (IOP) and central corneal thickness (CCT) in ethnically diverse, myopic young adults enrolled in COMET (the Correction of Myopia Evaluation Trial) and their association with ocular and demographic factors. IOP (Goldmann tonometry), CCT (handheld pachymetry), refractive error (cycloplegic autorefraction), and ocular components (A-scan ultrasonography) were measured in 385 of the original 469 subjects (mean age = 20.3 ± 1.3 years). Summary statistics for descriptive analysis, Pearson correlation coefficients, and linear regression models to formally test the association of IOP and CCT with other covariates were used. Mean IOP was 15.1 ± 0.1 mm Hg and differed by ethnicity and CCT but did not vary by gender, magnitude of myopia, or vitreous chamber depth (VCD). Adjusting for CCT, IOP in black participants was 1.8 mm Hg higher than in Hispanics (p = 0.0001) and 0.8 mm Hg higher than in whites (p = 0.03). Mean CCT was 562.4 ± 1.8 μm and differed by ethnicity, VCD, and IOP after adjusting for covariates. Blacks had thinner corneas than Asians, whites, and Hispanics, with adjusted differences of 15.4, 11.8, and 15.3 μm (p = 0.03, < 0.01 and < 0.01), respectively. Eyes with shorter VCD (<17.8 mm) had 8.0-μm thinner CCT (p = 0.03). CCT did not vary by gender or magnitude of myopia. Overall, a modest positive correlation (r = 0.25, P < 0.0001) was found between IOP and CCT, which varied by ethnicity in Asians (r = 0.47; p = 0.008), blacks (r = 0.29; p = 0.002), and whites (r = 0.24; p = 0.002). Myopic, black young adults had higher IOP and thinner corneas relative to other ethnic groups, suggesting that evaluation of these parameters during routine examination of these individuals should begin at a young age. Their thinner CCT should also be considered in evaluations for refractive surgery.

Factors Associated with Macular Thickness in the COMET Myopic Cohort

To determine whether macular thickness is associated with ethnicity, gender, axial length (AL), and severity of myopia in a cohort of young adults from the Correction of Myopia Evaluation Trial (COMET). Eleven years after their baseline visit, 387/469 (83%) subjects returned for their annual visit. In addition to the protocol-specific measures of spherical equivalent refractive error (SER) and AL, high-resolution macular imaging also was performed with optical coherence tomography (RTVue). From these scans, full-thickness values for the central (1 mm), parafoveal (1 to 3 mm), and perifoveal (3 to 5 mm) annular regions were calculated. Gender, ethnicity, AL, and SER were examined for associations with macular thickness using univariate and multivariable linear regression analyses. In the 377 subjects with usable data (mean age = 21.0 ± 1.3 years), the mean SER ± SD was -5.0 ± 1.9 D and mean AL was 25.4 ± 0.9 mm. Mean foveal thickness was 252.0 ± 20.1 μm in the center, 315.6 ± 14.0 μm in the parafovea, and 284.4 ± 12.9 μm in the perifovea. In the best-fit multivariable model that adjusted for gender, ethnicity, and AL, females had significantly thinner maculas than males for all three regions (p < 0.0001), with the largest difference in the center (12.8 μm, 95% confidence interval: 9.2 to 16.4). The effect of ethnicity was strongest in the central fovea, with African-Americans, Asians, Hispanics, and mixed ethnic groups having thinner maculas than whites (all p values < 0.005). Increased AL was significantly associated with slightly thicker central foveas (p = 0.001) and thinner parafoveal (p = 0.02) and perifoveal (p < 0.0001) regions. In this ethnically diverse cohort of moderate and high myopes, females and African-Americans were found to have the thinnest central foveas. Whether such thinning in the macula as a young adult is a risk factor for future disease remains to be determined.

Myopia Progression in Children Wearing Spectacles vs. Switching to Contact Lenses.

PURPOSE: To investigate myopia progression in Correction of Myopia Evaluation Trial (COMET) participants who switched to soft contact lenses (CLs) vs. remained in spectacles after the clinical trial ended. METHODS: Four hundred sixty-nine ethnically diverse, 6- to 11-year-old myopic children were randomly assigned to wear single vision lenses (SVLs) or progressive addition spectacle lenses (PALs) for 5 years as part of COMET. Afterwards they could choose another lens type, including CLs. Data in this article are from 286 participants who wore their original spectacle lenses for 6 years (n = 199) or wore CLs most or all the time between the 5- and 6-year visits (n = 87). Refractive error and axial length (AL) were measured after cycloplegia with 1% Tropicamide. The primary outcome was myopia progression between the 5- and 6-year visits. Two-year myopia progression was evaluated in a subset of 183 participants who wore the same lens type for an additional year. Myopia progression and AL were compared between the two lens groups using multiple linear regression. RESULTS: Participants in the two groups were similar with respect to age, ethnicity, myopia at 5-years, accommodation and phoria, but more girls switched to CLs than remained in spectacles (p < 0.0001). Mean (+/-SD) myopia progression was higher (p = 0.003) after 1 year in the CL group[-0.28+/- 0.33 diopter (D)] than the spectacle group (-0.14+/- 0.36 D), and remained higher after 2 years in the 2-year subset (-0.52+/- 0.46 D vs.-0.25+/- 0.39 D, p < 0.0001). Results were similar after adjustment for related factors. No significant differences in AL were found between groups after adjustment. Corneal curvature remained unchanged in both groups. CONCLUSIONS: COMET children switching from glasses to CLs experienced a small, statistically significant but clinically inconsequential increase in myopia progression.

IOP, Myopic Progression and Axial Length in a COMET Subgroup

Relationships between intraocular pressure (IOP) and baseline characteristics are explored in a subgroup of children participating in the Correction of Myopia Evaluation Trial. The 5-year follow-up also provides information on the relationship between IOP, myopic progression, and change in axial length. Right eye IOP, cycloplegic autorefraction, and axial length were measured at baseline and annually in 104/118 children at one of the Correction of Myopia Evaluation Trial centers. At baseline, IOP for the cohort was 15.92 +/- 4.16 mm Hg. IOP decreased (0.125 mm Hg/year) over the follow-up (p = 0.05). IOP of Blacks (n = 17; 19.88 +/- 4.24 mm Hg) was higher than Hispanics (n = 50; 15.77 +/- 2.44 mm Hg, p = 0.006), Whites (n = 25; 14.51 +/- 1.75 mm Hg, p = 0.0001) and all non-Blacks combined (n = 87; 15.38 +/- 2.26 mm Hg, p = 0.0006). IOP averaged over the six visits did not differ by gender (mean difference = 0.66 mm Hg). There was no significant association between baseline IOP and baseline myopia or myopic progression, and no significant relationship between IOP the year prior to myopic progression measured over the following year. The same results were found for IOP and axial length. Small but significant ethnic differences were noted in the IOP of myopic children, with Blacks having higher values. IOP was not associated with gender, baseline refractive error, baseline axial length, myopic progression, or change in axial length over the 5-year observation period.

Role of Parental Myopia in the Progression of Myopia and Its Interaction with Treatment in COMET Children

The present study investigated the relationship between parental refractive error and myopia progression in their offspring and the interaction between parental ametropia and the effects of wearing progressive-addition (PALs) or single-vision (SVLs) lenses on the progression of myopia in children enrolled in the Correction of Myopia Evaluation Trial (COMET). The progression of myopia in a subset of COMET children (N= 232; 49% of initial group) was defined as the difference in mean spherical equivalent refraction of both eyes obtained by cycloplegic autorefraction between the baseline and 5-year visit. Parental refractions were obtained by noncycloplegic autorefraction (81%) or from recent eye examination records (19%). The number of myopic parents (mean spherical equivalent refraction </=-0.75 D) was directly related to myopia progression among children wearing SVLs: myopia in children with no (zero) myopic parents progressed (mean +/- SE) -1.81 +/- 0.18 D and with one myopic parent, -2.04 +/- 0.13) D; these amounts were significantly less than the progression of children with two myopic parents (-2.59 +/- 0.19 D). In the PAL group, progression was not significantly related to the number of myopic parents and was -2.01 D overall. Among children with two myopic parents, progression was -2.00 D in the PAL group, significantly less than the progression of children wearing SVLs (P = 0.03). Among children with zero or one myopic parent, progression did not differ significantly between the lens groups. When the data were adjusted for covariates, the interaction between treatment effect and number of myopic parents was significant (P = 0.01). Over the 5-year study period, axial length increased 0.93 +/- 0.07 mm in children with two myopic parents wearing PALs and 1.18 +/- 0.07 mm in children with two myopic parents wearing SVLs (P = 0.01). The axial length increase in children wearing SVLs and with two myopic parents was significantly more than the 0.89 +/- 0.07 mm increase in children wearing SVLs and with zero myopic parents (P = 0.015). Parental refraction was related to myopia progression and changes in axial length. Among COMET children with two myopic parents, myopia progression and increases in axial length were slower in the group wearing PALs than in those wearing SVLs, by a statistically significant but clinically minor amount. Because this study was ancillary to COMET and the present analyses are based on a subset of participants, conclusions must be regarded as suggestive.

Factors Associated with High Myopia After 7 Years of Follow-up in the Correction of Myopia Evaluation Trial (COMET) Cohort

Purpose: To evaluate factors associated with the development of high myopia (worse than −6.00 D) over 7 years of follow-up in the COMET cohort. Methods: COMET enrolled 469 ethnically diverse children (6–11 years) with myopia between −1.25 and −4.50 D. They were randomized to either progressive addition lenses (PALs) or single vision lenses (SVLs), and followed for 5 years in their original lens assignment and 2 additional years wearing either spectacles (PALs or SVLs) or contact lenses. Refractive error was measured annually by cycloplegic autorefraction and axial length by A-Scan ultrasonography. Myopia for each child was defined as the mean spherical equivalent refractive error (SER) of the 2 eyes. Analyses were based on 7 years of follow-up. Time to high myopia was analyzed by Cox proportional hazard models and linear regression. Parental refraction data were available from 240 COMET subjects. Results: Younger (6–7 years) versus older (11 years) age at baseline was a significant risk factor (adjusted hazard ratio (HR) = 6.6, 95% CI = 3.4, 12.7) for having high myopia within 7 years. More (SER from −2.26 to −4.50 D) vs. less (SER from −1.25 to −2.25 D) baseline myopia was also a significant risk factor for high myopia at 7 years (adjusted HR = 7.4, 95% CI = 4.4, 12.4). Gender, ethnicity, and treatment assignment were not associated with the risk of high myopia within 7 years. Increased number of myopic parents was associated with a significant risk of high myopia in the children (p = 0.008). Conclusions: Children who developed high myopia during 7 years of follow-up were younger and had more myopia at baseline. They also were more likely to have two myopic parents. These children may be at greater risk for sight-threatening conditions later in life.

Evaluating Masking in a Randomized, Double-Masked Clinical Trial in Children With Myopia

The purposes of this study were to evaluate the success of masking in the Correction of Myopia Evaluation Trial (COMET), a study designed as a randomized, double-masked clinical trial comparing the effect of progressive addition lenses (PALs) with single-vision lenses (SVLs) in slowing myopia progression among children and to investigate the impact of unmasking on the treatment effect. The success of masking of children and parents was assessed by questionnaires administered after the clinical trial results were reported and before families were informed of their child's lens assignment. Children and parents who correctly guessed their assignment with absolute or "pretty sure" certainty were considered as unmasked. The role of children's age, gender, and ethnicity in unmasking was evaluated using logistic regression. The impact of unmasking on the treatment effect at 3 years was investigated using analysis of variance. The success of masking of the study optometrists was assessed by data collected at the child's follow-up visits. Overall 93% (436 of 469) of the COMET children responded to the questions about lens assignment and certainty. Thirty-seven percent (163 of 436) of children met the criteria for being unmasked with similar results from the parents. The majority (91%) of the 163 "unmasked" children reported that their glasses were the main reason for lens identification. Although children 10 to 11 years at baseline became unmasked more often than did children 6 to 9 years (44% vs. 31%, p = 0.01), there was no difference between boys and girls becoming unmasked (p = 0.2). The treatment effect did not differ between the masked and unmasked children (p = 0.69). The study optometrists became unmasked for five children over the course of 3-year follow up. Masking was successfully maintained for the study optometrists and the majority (63%) of COMET children. Although some children were able to identify their lens assignment, the primary study outcome was not affected by unmasking.

Reasons for high retention in pediatric clinical trials: comparison of participant and staff responses in the Correction of Myopia Evaluation Trial

The Correction of Myopia Evaluation Trial (COMET), a randomized, multicenter clinical trial of myopia progression in children, had an exceptionally high retention rate of 98.5% (462/469) at three years of follow-up. The present investigation was designed to evaluate and compare the reasons for COMET's high retention rate according to participating families and clinical center staff. Families (n = 411) and staff (n = 35) completed a confidential 19-item questionnaire by indicating families' levels of preference for each item, and rating its importance in keeping families in the study. The questionnaire evaluated study features in four categories: staff characteristics, operational aspects, specific study elements, and incentives. Results showed that most families viewed the study very favorably. Features that appealed to 90% or more families and promoted continued study participation included staff attributes such as friendliness, responsiveness and encouragement, and aspects pertaining to standard of care such as completeness of eye exam, quality of eye care and free eyeglasses. Compared to families, staff tended to underestimate the importance of the following features for retention: seeing the same staff at each visit, appointment reminders, center location, newsletters, commitment to the study, being part of a nationwide study, length of the study, association with a college of optometry, completeness of eye exam, and eye drops (p < 0.05 by chi-square analyses). However, staff responses also revealed less preferred components of the study protocol (e.g., eye drops), to which families might have been reluctant to respond unfavorably. Our findings highlight the importance of intangible factors such as staff attributes and participants' study commitment in maintaining high retention rates, and the usefulness of surveying both families and staff.

Relationship of Age, Sex, and Ethnicity With Myopia Progression and Axial Elongation in the Correction of Myopia Evaluation Trial

To identify the baseline factors independently related to 3-year myopia progression and axial elongation in COMET. A total of 469 children were enrolled, randomly assigned to progressive addition lenses with a + 2.00 diopter (D) addition or to single vision lenses and observed for 3 years. Eligible children were 6 to 11 years old, with spherical equivalent myopia of - 1.25 to - 4.50 D, bilaterally. The primary and secondary outcomes, myopia progression by cycloplegic autorefraction and axial elongation by A-scan ultrasonography, were measured annually. Multiple linear regression was used to adjust for covariates, including treatment. Younger baseline age (6-7 vs 11 years, 8 vs 11 years, and 9 vs 11 years, P<.001; 10 vs 11 years, P = .04), female sex (P = .01), and each ethnic group compared with African Americans (Asian, P = .02; Hispanic, P = .002; mixed, P = .002; white, P = .001) were independently associated with faster 3-year progression. Children aged 6 to 7 years had the fastest progression of all age groups, progressing by a mean (+/- SD) of 1.31 D +/- 0.13 more than children aged 11 years. Females progressed 0.16 D more than the males. Children of mixed, Hispanic, Asian, and white ethnicity progressed more than African American children by 0.49 D +/- 0.16, 0.33 D +/- 0.11, 0.32 D +/- 0.13, 0.27 D +/- 0.08, respectively. Age and ethnicity, but not sex, were independently associated with axial elongation. Among these myopic children, a 0.5 mm increase in axial length was associated with 1 D of myopia progression. Younger baseline age was the strongest factor independently associated with faster myopic progression and greater axial elongation at 3 years. African American children had less myopic progression and axial elongation than the other ethnic groups.

Adaptability of Myopic Children to Progressive Addition Lenses with a Modified Fitting Protocol in the Correction of Myopia Evaluation Trial (COMET)

The purpose of this study was to evaluate the adaptability of myopic children participating in the Correction of Myopia Evaluation Trial (COMET) to the use of progressive addition lenses (PALs) with a modified fitting protocol of setting the distance fitting cross 4 mm above the pupil center. COMET was a multicenter, randomized clinical trial to evaluate whether PALs vs. single-vision lenses (SVLs) slowed the rate of progression in children with juvenile-onset myopia over 3 years. Of the 469 children enrolled, 234 were assigned to SVLs and 235 were assigned to PALs (+2.00 D near addition), which were fit according to a standard study protocol with the fitting cross positioned 4 mm above the pupil center. The children's adaptability to the use of PALs was evaluated by comparing the frequency and reasons for problem visits, visual symptoms, cover test results, and adherence to wearing glasses between treatment groups. During the first 3 years of follow-up, no differences were observed between children wearing PALs and those wearing SVLs with respect to the number or reasons for problem visits. One week after receipt of the study glasses, children wearing PALs showed a higher frequency of three visual symptoms related to adaptability: looking down from the blackboard and getting items on their desk in focus (p = 0.001), blur when reading (p = 0.003), and difficulty going down steps (p = 0.02). Children wearing PALs were more likely to report at least one adaptation symptom at 1 week: odds ratio of 2.76 (95% confidence interval = 1.28-5.95). By 1 month, these differences disappeared and the frequency of all visual symptoms remained low and similar for both treatment groups over 3 years. Strabismus was observed on cover test in five children (three SVLs, two PALs). None of the children had to be changed from PALs to SVLs, whereas two of the children were changed from SVLs to PALs as a result of binocular vision problems. The children and parents reported adherence to wearing the eyeglasses approached 100% compliance throughout the follow-up period for both groups. Most (98%) of the 235 children assigned to PALs maintained the modified fitting protocol without any problems over 3 years. These data show that children can safely and comfortably wear PALs for at least 3 years.

Evaluating the Self-esteem of Myopic Children Over a Three-Year Period: The COMET Experience

The purposes of this study were to evaluate self-esteem over 3 years in the 469 myopic children participating in the Correction of Myopia Evaluation Trial (COMET), and to examine its relationship with lens assignment (progressive addition lenses [PALs] vs. single-vision lenses [SVLs]), myopia progression, and several other ocular and demographic characteristics. Data collection included refractive error measurements, child-reported visual symptoms, attitude toward glasses, adherence, and self-esteem as measured by the Self-Perception Profile for Children (SPPC). A two-way analysis of variance (treatment group x time) was performed to examine whether PAL and SVL wearers differed in self-esteem over time. Multiple regression analyses were used to evaluate associations between self-esteem at follow-up and relevant factors identified by univariate analyses. Regardless of lens assignment or myopia progression, COMET children reported moderate to high levels of self-esteem at follow-up in the areas of scholastic and athletic competence, physical appearance, social acceptance, behavioral conduct, and global self-worth. Mean scores ranged from 2.87 (+/- 0.68) on athletic competence to 3.40 (+/- 0.56) on global self-worth. Self-esteem changed significantly (p < 0.05) over 3 years in the domains of scholastic competence, social acceptance, and physical appearance. Self-esteem at follow-up was associated with visual symptoms, attitude toward glasses, age, gender, and ethnicity. Lens assignment and myopia progression were not associated with self-esteem in the COMET cohort. These children had high levels of self-esteem, suggesting that having myopia does not negatively impact self-esteem. Follow-up reports will monitor self-esteem and related factors in this cohort of myopic children over the course of adolescence and early adulthood.