Peripheral refractive changes associated with myopia progression

Purpose.: To evaluate the changes in peripheral refraction profiles associated with myopia progression and treatment modalities used in the Cambridge Anti-Myopia Study. Methods.: One hundred and seventy-seven myopes in the age range of 14 to 22 years were enrolled in the study. The mean spherical equivalent refractive error was −3.12 ± 1.87 diopters (D) and the refractive error of each participant was corrected with contact lenses. The participants were randomly assigned to one of four treatment groups, which included: altered spherical aberration and vision training, altered spherical aberration only, vision training only, and control. Peripheral refractive error was measured using an open field autorefractor in the central 60° of the retina in 10° steps. The refractive error was measured using cycloplegic autorefraction. Two-year refractive progression data and initial peripheral refraction measurements were available in 113 participants. Measurements of peripheral refraction and cycloplegic refraction were obtained at three visits over 2 years in 12-month intervals for 92 participants. Results.: All subjects showed a relative peripheral hyperopia, especially in the nasal retina. A limited magnitude of myopia progression of −0.34 ± 0.36 D over 2 years was found in each of the four groups on average. There were no significant differences in the rate of progression between any of the treatment groups (P > 0.05). Initial peripheral J45 astigmatic refractive error at 20° and 30° in the nasal retina was weakly correlated with progression of myopia over 2 years (r = −0.27, P = 0.004 and r = −0.20, P = 0.040, respectively; n = 113). The change in spherical equivalent peripheral refractive error at 30° nasal retina over time was also significantly correlated with progression of myopia especially at 24 months (r = −0.24, P = 0.017, n = 92). Conclusions.: Relative peripheral hyperopia is associated with myopia. Myopia progression may be weakly linked to changes in the peripheral refraction profiles in the nasal retina. However, a causative link between peripheral refractive error and myopia progression could not be established

The Cambridge Anti-myopia Study: variables associated with myopia progression

Purpose: To identify variables associated with myopia progression and to identify any interaction between accommodative function, myopia progression, age, and treatment effect in the Cambridge Anti-Myopia Study. Methods: Contact lenses were used to improve static accommodation by altering ocular spherical aberration, and vision training was performed to improve dynamic accommodation. One hundred forty-two subjects, aged 14–21 years, were recruited who had a minimum of −0.75D of myopia. Subjects were assigned to contact lens treatment only, vision training only, contact lens treatment and vision training, or control group. Spherical aberration, lag of accommodation, accommodative convergence/accommodation (AC/A) ratio, accommodative facility, ocular biometry, and refractive error were measured at regular intervals throughout the 2-year trial. Results: Ninety-five subjects completed the 24-month trial period. There was no significant difference in myopia progression between the four treatment groups at 24 months. Age, lag of accommodation, and AC/A ratio were significantly associated with myopia progression. There was a significant treatment effect at 12 months in the contact lens treatment group in younger subjects, based on a median split, aged under 16.9 years (p = 0.005). This treatment effect was not maintained over the second year of the trial. Younger subjects experienced a greater reduction in lag of accommodation with the treatment contact lens at 3 months (p = 0.03), compared to older contact lens treatment and control groups. There was no interaction between AC/A ratio and contact lens treatment effect. Conclusions: Age, lag of accommodation, and AC/A ratio were significantly associated with myopia progression. Although there was no significant treatment effect at 24 months, an interaction between age and contact lens treatment suggests younger subjects may be more amenable, at least in the short term, to alteration of the visual system using optical treatments

Aberration control and vision training as an effective means of improving accommodation in individuals with myopia

Purpose.: To test the efficacy of a novel dual treatment for improving accommodative accuracy and dynamics in young persons with myopia. Methods.: Ninety-three young persons with myopia (mean spherical equivalent, −3.0 ± 1.8 D; age 16.8 ± 2.1 years; spherical aberration +0.06 ± 0.04 μm) participated in the study. Custom-designed soft contact lenses were used to alter ocular SA to −0.10 μm to improve accommodative accuracy and reduce any lag of accommodation. A vision training regimen was performed for 18 minutes per day for up to 6 weeks to improve speed of dynamic accommodation. Control groups had contact lenses with no added SA and/or no exercises. To avoid any effects of natural levels of negative aberration on the results of the study, all participants who had negative SA were excluded. Results.: The treatment contact lenses produced a significant reduction in lag of accommodation (P < 0.05) at all proximal viewing distances measured. The vision training measurement and treatment resulted in a significant increase in distance facility rate for all groups compared with their own baselines (P < 0.05). Near facility rate improved in the vision training treatment group only compared with its baseline (P < 0.05). Both positive and negative response times for distant viewing were significantly shorter in all groups after training compared with their baseline values (P < 0.05). At near, the positive response times were decreased significantly (P < 0.05) in both groups, whereas the negative response times decreased significantly only in the vision training treatment group. Conclusions.: After 3 months, the dual treatments (altering SA and vision training) used in the study were effective in modifying accommodation. The static accommodative response to targets at proximal distances was increased by the altered SA contact lenses and rates of dynamic accommodation improved with vision training