Can bifocals slow myopia progression? A randomized trial of rigid gas permeable contact lenses to reduce progression of children's myopia. A randomized trial of the effects of rigid contact lenses on myopia progression. Randomized trial of effect of bifocal and prismatic bifocal spectacles on myopic progression: two-year results. Houston Myopia Control Study: a randomized clinical trial. Part II. Final report by the patient care team. The possible effect of undercorrection on myopic progression in children. An intervention trial on efficacy of atropine and multi-focal glasses in controlling myopic progression. A randomized clinical trial of bifocal glasses for myopic children with esophoria: results after 54 months. A randomized clinical trial of progressive addition lenses versus single vision lenses on the progression of myopia in children. The effectiveness of progressive addition lenses on the progression of myopia in Chinese children. Effect of spectacle use and accommodation on myopic progression: final results of a three-year randomised clinical trial among schoolchildren.
Retrospective studies have suggested that in children with near point esophoria, bifocals can slow myopia progression by about 50 percent. A prospective study was conducted to test this hypothesis.
                Thirty-two children, all with near point esophoria, were randomly divided into either correction with single-vision or with bifocal lenses containing a +1.25 D and. Axial length and refraction were measured under cycloplegia every 6 months for 18 months. Twenty-eight children completed the study.
                Myopia progressed at an equal rate in both groups for the first 12 months. Progression was much faster during the first 6 months, which was during the school year, than during the second 6 months, which included all of the summer vacation (0.64 D/yr vs 0.29 D/yr). During the last 6 months, myopia progressed rapidly for children in single-vision lenses (0.80 D/yr) but slowly for those in bifocals (0.37 D/yr). A repeated-measure analysis of variance showed that season of the year had a significant effect on myopia progression (p > 0.002) and that the effect differed for the two treatment groups (p > 0.043). Over the whole 18-month study, myopia progressed at rate of 0.57 D/yr for those in single-vision lenses and 0.39 D/yr in those in bifocals (p = 0.26).
                Bifocals seemed to slow myopia progression in these children with near-point esophoria, although a longer-term study with more subjects is needed to confirm this finding. Myopia progressed more rapidly during the school year than during summer vacation. To test whether rigid gas permeable (RGP) contact lens wear can reduced the rate of myopia progression in school age children.
                Randomized clinical trial.
                
                Single clinical center.
                Both eyes of 428 Singaporean children.
                6 through 12 years of age with myopia between -1 and -4 diopters, astigmatism <or= 2 diopters, no prior contact lens wear, no other ocular pathologies.Intervention: Spectacle or RGP lens correction for myopia. After a 3-month adaptation period, 383 children were followed, and 298 (78%) remained after 24 months. Outcome measures: Cycloplegic subjective refraction, keratometry, and axial length measured at 12 and 24 months.
                Children who adapted to contact lenses wore them for a median of 7 hours per day, but no more than 40% wore them at least 8 hours per day, 7 days per week. Spectacles were worn for a median of 15 hours per day at the time of the 24-month follow-up. There was an increase in the spherical equivalent of -1.33 and -1.28 diopters (P =.64), and axial length increased by 0.84 and 0.79 mm (P =.38) over 2 years among children randomized to contact lenses and spectacles, respectively. Adjustment for baseline differences between the groups and for hours per day of contact lens wear did not alter these findings.
                Rigid gas permeable lenses did not slow the rate of myopia progression, even among children who used them regularly and consistently. It is unlikely that this intervention holds promise as a method by which to slow the rate of progression of myopia in children. To compare the effects of rigid gas-permeable contact lenses (RGPs) and soft contact lenses (SCLs) on myopia progression in children.
                We randomly assigned 116 subjects to wear RGPs or SCLs. Subjects underwent cycloplegic autorefraction, keratometry, and A-scan ultrasonographic axial length measurements at each annual visit. All analyses were conducted according to the original randomization assignment. The primary outcome measure was the 3-year change in spherical equivalent cycloplegic autorefraction.
                The mean +/- SD spherical equivalent cycloplegic refractive error progressed -1.56 +/- 0.95 diopters (D) for RGP wearers and -2.19 +/- 0.89 D for the SCL wearers during the 3 years of the study (analysis of covariance [ANCOVA], P<.001). The axial growth of the eyes was not significantly different between treatment groups (ANCOVA, P = .57). The steep corneal meridian of the RGP wearers steepened 0.62 +/- 0.60 D, and that of the SCL wearers steepened 0.88 +/- 0.57 D during the 3 years (ANCOVA, P = .01).
                The RGP wearers' myopia progressed less than that of the SCL wearers. The corneal curvature of the SCL wearers steepened more than that of the RGP wearers, but the axial growth was not significantly different between the groups. Most refractive error treatment effect was limited to the first year of the trial. The results of the study provide information for eye care practitioners to share with their patients, but they do not indicate that RGPs should be prescribed primarily for myopia control. To determine whether bifocal and prismatic bifocal spectacles could control myopia in children with high rates of myopic progression.
                This was a randomized controlled clinical trial. One hundred thirty-five (73 girls and 62 boys) myopic Chinese Canadian children (myopia of > or =1.00 diopters [D]) with myopic progression of at least 0.50 D in the preceding year were randomly assigned to 1 of 3 treatments: (1) single-vision lenses (n = 41), (2) +1.50-D executive bifocals (n = 48), or (3) +1.50-D executive bifocals with a 3-prism diopters base-in prism in the near segment of each lens (n = 46).
                Myopic progression measured by an automated refractor under cycloplegia and increase in axial length (secondary) measured by ultrasonography at 6-month intervals for 24 months. Only the data of the right eye were used.
                Of the 135 children (mean age, 10.29 years [SE, 0.15 years]; mean visual acuity, -3.08 D [SE, 0.10 D]), 131 (97%) completed the trial after 24 months. Myopic progression averaged -1.55 D (SE, 0.12 D) for those who wore single-vision lenses, -0.96 D (SE, 0.09 D) for those who wore bifocals, and -0.70 D (SE, 0.10 D) for those who wore prismatic bifocals. Axial length increased an average of 0.62 mm (SE, 0.04 mm), 0.41 mm (SE, 0.04 mm), and 0.41 mm (SE, 0.05 mm), respectively. The treatment effect of bifocals (0.59 D) and prismatic bifocals (0.85 D) was significant (P < .001) and both bifocal groups had less axial elongation (0.21 mm) than the single-vision lens group (P < .001).
                Bifocal lenses can moderately slow myopic progression in children with high rates of progression after 24 months. APPLICATIONS TO CLINICAL PRACTICE: Bifocal spectacles may be considered for slowing myopic progression in children with an annual progression rate of at least 0.50 D. In a randomized clinical trial designed to test the efficacy of bifocal lenses for the control of juvenile myopia, each of 207 children between the ages of 6 and 15 years wore single vision lenses, +1.00 D add bifocals, or +2.00 D add bifocals for a period of 3 years. For the 124 subjects who completed the study, the mean changes in refraction were found to be -0.34 D per year for subjects wearing single vision lenses, -0.36 D per year for those wearing +1.00 D add bifocals, and -0.34 D per year for those wearing +2.00 D add bifocals. These differences were not statistically significant. When subjects in all three treatment groups were combined, it was found that the rate of progression tended to be the most rapid for subjects who entered the study at an early age with a large amount of myopia, and tended to be the least rapid for subjects who entered the study at a later age with a small amount of myopia. It was also found that subjects having with-the-rule astigmatism progressed more slowly than those having no astigmatism or against-the-rule astigmatism. Undercorrection has recently been found to enhance the rate of progression of myopia. This result was thought to be controversial as it contrasted with expectations based on animal studies, as well as the results found wearing progressive addition lenses. The aim of the present study was to again determine the effect of undercorrection on the progression of myopia in a random population of children who are known to be very susceptible to myopia.
                A cohort of 48 myopic children, aged six to 15 years was randomly assigned to either a fully corrected group (n = 23) or to an undercorrected group (n = 25). The subjects in the latter group were blurred by +0.50 D. The prospective study extended over a period of 18 months. Optometric examinations were carried out at the beginning of the study, then at six-month, 12-month and 18-month follow-up.
                Undercorrection produced a slight but not statistically significant increase in myopic progression over the 18-month period equal to 0.17 D, compared to full correction. A similar trend towards an increase in progression was noted in females and in children with near esophoria.
                This study supports the evidence that undercorrection does not represent an effective therapy to slow the rate of early-onset myopic progression, regardless of near heterophoria. This randomized clinical trial assessed the treatment effects of atropine and/or multi-focal lenses in decreasing the progression rate of myopia in children.
                Two hundred and twenty-seven schoolchildren with myopia, aged from 6 to 13 years, who were stratified based on gender, age and the initial amount of myopia were randomly assigned to three treatment groups: 0.5% atropine with multi-focal glasses, multi-focal glasses, and single vision spectacles. Each subject was followed for at least eighteen months. These results report on the 188 patients available for the follow-up.
                The mean progression of myopia in atropine with multi-focal glasses group (0.41 D) was significantly less than the multi-focal (1.19 D) and single vision group (1.40 D) (p < 0.0001). But no significant difference was noted between the last two groups (p = 0.44). The progression of myopia was significantly correlated with the increases of axial length (r = 0.65, p = 0.0001), but not with the changes of corneal power (r=-0.09), anterior chamber depth (r = -0.023), lens thickness (r = -0.08), or intra-ocular pressure (r = -0.008).
                The 0.5% atropine with multi-focal lenses can slow down the progression rate of myopia. However, multi-focal lenses alone showed no difference in effect compared to control. We previously reported results of a randomized clinical trial of bifocals as a type of myopia correction for children with near-point esophoria. After 30 months, the rate of myopia progression in 36 children wearing bifocals averaged 0.40 D/yr compared to 0.50 D/yr in 39 children wearing single-vision glasses (p= 0.046, age-adjusted). Here we report on the 46 children in that study who completed 54 months of followup.
                For each treatment group, we examined the pattern of change in myopia over the first and second halves of the 54-month period to see if the beneficial effect of wearing bifocals was present initially for those 46 children, as it was in the entire group, and to see if the myopia-slowing effect continued to accumulate during the second part of the study. During the last 12 months of the 54-month period, subjects were free to select any mode of myopic treatment, but this intent-to-treat analysis classified all children according to their original treatment assignment.
                During the first 24 months, the pattern of change in myopia differed between the two groups (p = 0.041), with those in bifocals showing slower progression. A similar trend was observed for vitreous chamber growth (p= 0.059). During the last 30 months, myopia progressed at a similar rate for both groups, including during the last year, when many subjects changed their mode of myopia correction.
                Wearing bifocals instead of single-vision glasses caused a slowing of myopia progression evident during the first two years. During the subsequent two-and-a-half years of followup, the difference in the degree of myopia was maintained, but did not increase. The purpose of the Correction of Myopia Evaluation Trial (COMET) was to evaluate the effect of progressive addition lenses (PALs) compared with single vision lenses (SVLs) on the progression of juvenile-onset myopia.
                COMET enrolled 469 children (ages 6-11 years) with myopia between -1.25 and -4.50 D spherical equivalent. The children were recruited at four colleges of optometry in the United States and were ethnically diverse. They were randomly assigned to receive either PALs with a +2.00 addition (n = 235) or SVLs (n = 234), the conventional spectacle treatment for myopia, and were followed for 3 years. The primary outcome measure was progression of myopia, as determined by autorefraction after cycloplegia with 2 drops of 1% tropicamide at each annual visit. The secondary outcome measure was change in axial length of the eyes, as assessed by A-scan ultrasonography. Child-based analyses (i.e., the mean of the two eyes) were used. Results were adjusted for important covariates, by using multiple linear regression.
                Of the 469 children (mean age at baseline, 9.3 +/- 1.3 years), 462 (98.5%) completed the 3-year visit. Mean (+/-SE) 3-year increases in myopia (spherical equivalent) were -1.28 +/- 0.06 D in the PAL group and -1.48 +/- 0.06 D in the SVL group. The 3-year difference in progression of 0.20 +/- 0.08 D between the two groups was statistically significant (P = 0.004). The treatment effect was observed primarily in the first year. The number of prescription changes differed significantly by treatment group only in the first year. At 6 months, 17% of the PAL group versus 30% of the SVL group needed a prescription change (P = 0.0007), and, at 1 year, 43% of the PAL group versus 59% of the SVL group required a prescription change (P = 0.002). Interaction analyses identified a significantly larger treatment effect of PALs in children with lower versus higher baseline accommodative response at near (P = 0.03) and with lower versus higher baseline myopia (P = 0.04). Mean (+/- SE) increases in the axial length of eyes of children in the PAL and SVL groups, respectively, were: 0.64 +/- 0.02 mm and 0.75 +/- 0.02 mm, with a statistically significant 3-year mean difference of 0.11 +/- 0.03 mm (P = 0.0002). Mean changes in axial length correlated with those in refractive error (r = 0.86 for PAL and 0.89 for SVL).
                Use of PALs compared with SVLs slowed the progression of myopia in COMET children by a small, statistically significant amount only during the first year. The size of the treatment effect remained similar and significant for the next 2 years. The results provide some support for the COMET rationale-that is, a role for defocus in progression of myopia. The small magnitude of the effect does not warrant a change in clinical practice. To evaluate the effectiveness of progressive addition lenses (PALs), with a near addition of +1.50 D, on the progression of myopia in Chinese children.
                We enrolled 178 Chinese juvenile-onset acquired myopes (aged 7-13 years, -0.50 to -3.00 D spherical refractive error), who did not have moderately or highly myopic parents, for a 2-year prospective study. They were randomly assigned to the PAL group or single vision (SV) group. Primary measurements, which included myopia progression and ocular biometry, were performed every 6 months. Treatment effect was adjusted for important covariates, by using a multiple linear regression model.
                One hundred and forty-nine subjects (75 in SV and 74 in PAL) completed the 2-year study. The myopia progression (mean +/- S.D.) in the SV and PAL groups was -1.50 +/- 0.67 and -1.24 +/- 0.56 D, respectively. This difference of 0.26 D over 2 years was statistically significant (p = 0.01). The lens type (p = 0.02) and baseline spherical equivalent refraction (p = 0.05) were significant contributing factors to myopia progression. Mean increase in the depth of vitreous chamber was 0.70 +/- 0.40 and 0.59 +/- 0.24 mm, respectively. This difference of 0.11 mm was statistically significant (p = 0.04). Age (p < 0.01) was the only contributing factor to the elongation of vitreous chamber. Different near phoria (p < 0.01) and gender (p = 0.02) caused different treatment effects when wearing SV lenses. However, there were no factors found to influence the treatment effect of wearing PALs.
                Compared with SV lenses, myopia progression was found to be retarded by PALs to some extent in Chinese children without moderately or highly myopic parents, especially for subjects with near esophoria or females. Two hundred and forty mildly myopic schoolchildren aged 9-11 years were randomly allocated to three treatment groups and the progression of myopia was followed-up for three years. The treatment groups were: (1) minus lenses with full correction for continuous use (the reference group), (2) minus lenses with full correction to be used for distant vision only, and (3) bifocal lenses with +1.75 D addition. Three-year refraction values were received from 237 children. The differences in the increases of the spherical equivalents were not statistically significant in the right eye, but in the left eye the change in the distant use group was significantly higher (-1.87 D) than in the continuous use group (-1.46 D) (p = 0.02, Student's t test). There were no differences between the groups in regard to school achievement, accidents, or satisfaction with glasses. In all three groups the more the daily close work done by the children the faster was the rate of myopic progression (right eye: r = 0.253, p = 0.0001, left eye: r = 0.267, p = 0.0001). Myopic progression did not correlate positively with accommodation, but the shorter the average reading distance of the follow-up time the faster was the myopic progression (right eye: r = 0.222, p = 0.0001, left eye: r = 0.255, p = 0.001). It seems that myopic progression is connected with much use of the eyes in reading and close work and with short reading distance but that progression cannot be reduced by diminishing accommodation with bifocals or by reading without spectacles.
The most likely effective treatment to slow myopia progression thus far is anti-muscarinic topical medication. However, side effects of these medications include light sensitivity and near blur. Also, they are not yet commercially available, so their use is limited and not practical. Further information is required for other methods of myopia control, such as the use of corneal reshaping contact lenses or bifocal soft contact lenses (BSCLs) with a distance center are promising, but currently no published randomized clinical trials exist.