Bifocal use in hyperopic anisometropic amblyopia treated with atropine: a proof-of-concept randomized trial

To investigate the effect of bifocal wearing in the amblyopic eye when atropine is used in the sound eye for the treatment of hyperopic anisometropic amblyopia.

Children 4-8 years old were randomly assigned to bifocal + atropine (n = 16) or only atropine (control, n = 19) groups of treatment in a proof-of-concept study. Measurements included visual acuity (logMAR), prism and cover test, stereoacuity (Randot preschool or Randot circles), contrast sensitivity (MARS test), accommodation (Grand Seiko WAM5500 and dynamic retinoscopy), retinoscopic and subjective refraction, before starting treatment and at 6 months, except accommodation, which was remeasured at 9-11 months. Main outcome measure was change in logMAR lines of visual acuity, and secondary outcome measures were change in stereoacuity and contrast sensitivity in the amblyopic eye, at 6 months.

Improvement in visual acuity of the amblyopic eye was significantly better (p = 0.04) in the atropine plus bifocal (3.3 ± 0.9 logMAR lines) than in the atropine only group (2.6 ± 0.8 logMAR lines), whereas change in stereoacuity and contrast sensitivity was not significantly different between the two groups. Differences in accommodative gain, which was impaired in the amblyopic compared to the sound eye, before treatment, decreased after treatment, in the atropine group (0.62 ± 0.16 vs 0.79 ± 0.2, p = 0.3), and atropine + bifocal group (0.69 ± 0.15 vs 0.82 ± 0.2, p = 0.4).

Use of bifocal lens add in the amblyopic eye of children with hyperopic anisometropic amblyopia, treated by atropine penalization, is beneficial in the follow-up period of 6 months.