Comparing homatropine and atropine in pediatric cycloplegic refractions

Purpose: To compare cycloplegic efficacy of homatropine and atropine in pediatric refractions and derive a regression formula to calculate refraction findings for both agents.

Methods: Children between the ages of 4 to 10 years with refractive error underwent cycloplegic refraction with 2% homatropine and 1% atropine by retinoscopy and automated refraction. Refractive data were compared by the use of power vector analysis. Primary outcome measures were spherical equivalent (SE), astigmatic components of refractive error (J(0) and J(45)), overall blur strength of refractive error, and residual accommodation.

Results: A total of 63 children with refractive error were enrolled (mean age, 6.7 ± 1.6 years). Compared with homatropine, atropine uncovered significantly greater hyperopic SE in patients with hypermetropia (4.2 ± 2.5 D [atropine] vs 3.5 ± 2.3 D [homatropine]; P < 0.001) as well as myopia (-1.8 ± 1.4 D [atropine] vs -2.1 ± 1.4 D [homatropine]; P < 0.001). Overall blur strength was significantly greater with atropine (3.1 ± 2.1 [atropine] vs 2.9 ± 1.9 [homatropine]; P = 0.003). Homatropine had a significantly greater residual accommodation (1.8 ± 0.4 D [atropine] vs 3.1 ± 0.5 D [homatropine]; P < 0.001). A regression formula was derived.

Conclusions: Of the 2 cycloplegic agents, atropine yielded more consistent results than homatropine; however atropine had a relatively slow onset and prolonged effect. Our regression formula may make it possible to derive atropine-like results while using the clinically more versatile homatropine.