Subjective quasi-vector-based refraction with a conventional phoropter.

Abstract

Purpose: To introduce a novel methodology for subjective refraction based on power vectors with a conventional phoropter.

Methods: A conventional phoropter was used to measure power vector components of refraction (M, J₀ and J₄₅) directly by using the sphere power (for M measurement) and the cylinder power combined with the Jackson cross-cylinders (for J₀ and J₄₅ measurements). Conventional subjective refraction was also performed, and this result was mathematically transformed into power vector notation for comparison purposes. Visual acuities with the conventional prescription and the quasi-vector-based prescription were compared.

Results: Refractive error from 40 healthy participants was measured by conventional and quasi-vector-based subjective refraction. No differences were found between methods for any of the power vector components of refraction (p > 0.21 in all cases). The visual acuity achieved with the prescriptions yielded similar values (p = 0.85).

Conclusions: Subjective refraction can be measured directly in power vector notation using a conventional phoropter without any additional adaptation and computation.