Myopia Control With Positively Aspherized Progressive Addition Lenses: A 2-Year, Multicenter, Randomized, Controlled Trial

Abstract

To the extent that has been tested and that can be tolerated by wearers of spectacle lenses, the high positive aspherization of the distance zone added to PALs does not enhance their therapeutic efficacy in slowing myopia progression. (http://www.anzctr.org.au/ number, ACTRN12608000566336).

Peripheral Design of Progressive Addition Lenses and the Lag of Accommodation in Myopes

“…Benchmark PAL and SVL PAL 2 has been used already in a clinical trial to investigate its efficacy in reducing progression of myopia in children. 21 There was a statistically significant (P ¼ 0.02) retardation of myopia progression (0.27 6 0.11 D, equivalent to a reduction ratio of 20%) during the 24-month period of the trial (0.24 D of which has occurred in the first 12 months) for the positively aspherized PAL with the 1.5 D of add power, when compared with a SVL control group. 21 The reduction of myopia progression using the PA-PAL and 1.50 D add power was within the range of reported retardations of myopia from earlier trials that used standard PALs.…”

“…21 There was a statistically significant (P ¼ 0.02) retardation of myopia progression (0.27 6 0.11 D, equivalent to a reduction ratio of 20%) during the 24-month period of the trial (0.24 D of which has occurred in the first 12 months) for the positively aspherized PAL with the 1.5 D of add power, when compared with a SVL control group. 21 The reduction of myopia progression using the PA-PAL and 1.50 D add power was within the range of reported retardations of myopia from earlier trials that used standard PALs. Standard single vision spherical lenses lead to higher lags of accommodation than the benchmark lens, indicating that the progressive addition lens is effective in the reduction of the LA.…”

“…This was a þ1.50 D addition positively aspherized (PA) PAL trialed for 2 years on the Asian 6-to 12-year-old myopes, having a corridor of 14 mm in length measured from the fitting cross (FC) to the near reference point (NRP). 21 The ability of this lens to reduce the LA was not known prior to the study. This lens was called PAL 2 in the trial and was used as a benchmark against which the ability of other lenses to reduce the LA was judged.…”

“…18,19 Later on, new PAL designs adapted for juvenile use with shorter corridors, making it easier for children to access the addition power, have been developed and tested. [21][22][23][24] Hasebe et al 22 investigated the influence of the addition power and the positive aspherization of the distance zone of the PAL on their efficacy to provide retardation of myopia progression. The positive aspherization of the distance zone did not retard myopia and a minimum of þ1.50 D addition was required to get an initial efficacy of 30% in the first year.…”

IMI – Industry Guidelines and Ethical Considerations for Myopia Control Report

“…[97][98][99][100][101][102][103][104][105][106] There are controversies with regard to the use of progressive addition and bifocal spectacles for MC, as some studies have found larger treatment effects occurring over a period of at least two years of lens wear, 12,107 whereas others carried out with progressive addition lenses designed to reduce peripheral hyperopic defocus have found minimal impact on reducing myopia progression. 108,109 Despite this, spectacle designs for MC are a necessary consideration, particularly in cases where other treatment options are not feasible (e.g., very young children, those unable to wear contact lenses due to access or cost, situations associated with poor hygiene conditions, or remote locations far from specialized eye care). Furthermore, a reserve pair of spectacles to the most recent prescription is always recommended for contact lens wearers.…”