Peripheral refraction and higher-order aberrations with cycloplegia and fogging lenses using the BHVI-EyeMapper

Abstract

PurposeTo determine if a fogging lens ameliorates accommodative effects driven by the closed-view design of the BHVI-EyeMapper (EM) instrument. We compared cycloplegic refraction and higher-order aberration measurements of the EM with those obtained with a fogging lens. MethodsTwenty-six, young, participants (15F, 25±5 years, range: 18–35 years, SE: +0.25D and −3.50D) with good ocular health were recruited. Five independent measurements of on- and off-axis refraction and higher-order aberrations were recorded across the horizontal visual field, under two conditions: non-cycloplegic measurements with +1.00D fogging lens and cycloplegia, always in the same sequence. The contralateral eye was occluded during the measurements. Two drops of 1% Tropicamide delivered within 5min facilitated cycloplegic measurements. All participants were refracted 30min after installation of the second drop. ResultsMean spherical equivalent measures of the non-cycloplegic condition were significantly more myopic than their cycloplegic counterparts (p<0.05); approximately by 0.50D centrally, increasing to 1.00D towards the periphery. The horizontal astigmatic component, J180, demonstrated small but statistically significant differences between the test conditions. Differences were predominant for eccentricities greater than 30°, in both nasal and temporal meridians. The oblique astigmatic component, J45, was not significantly different between the test conditions. The primary spherical aberration coefficient C(4, 0) was significantly less positive for the non-cycloplegic state than its cycloplegic counterpart. This result held true across the entire horizontal visual field. The horizontal coma and trefoil coefficients C(3, 1) and C(3, 3) were not significantly different between the two conditions. ConclusionsThe use of +1.00D fogging lens without cycloplegia did not provide complete relaxation of accommodation. The discrepancies between cycloplegic and non-cycloplegic EM measurements were found to be more pronounced for peripheral field angles than central measures, for both M and J180 components.