To evaluate the performance of a holographic logMAR chart
for the subjective spherical refraction of the human eye.
Bland-Altman analysis was used to assess the level of agreement between subjective spherical refraction using the holographic logMAR chart
and conventional autorefraction and subjective spherical refraction.
The 95% limits of agreement (LoA) were calculated between holographic refraction
and the two standard methods (subjective and autorefraction). Holographic refraction
has a lower mean spherical refraction when compared to conventional refraction (LoA 0.11 ± 0.65 D) and when compared to autorefraction (LoA 0.36 ± 0.77 D). After correcting for systemic bias, this is comparable between autorefraction and conventional subjective refraction
(LoA 0.45 ± 0.79 D). After correcting for differences in vergence distance and chromatic aberration between holographic and conventional refraction, approximately 65% (group 1) of measurements between holography and conventional subjective refraction
were similar (MD = 0.13 D, SD = 0.00 D). The remaining 35% (group 2) had a mean difference of 0.45 D (SD = 0.12 D) between the two subjective methods. Descriptive statistics showed group 2’s mean age (21 years, SD = 13 years) was considerably lower than group 1’s mean age (41 years, SD = 17), suggesting accommodation may have a role in the greater mean difference of group 2.
Overall, holographic refraction
has good agreement with conventional refraction and is a viable alternative for spherical subjective refraction
. A larger bias between holographic and conventional refraction was found in younger subjects than older subjects, suggesting an association between accommodation and myopic over-correction during holographic refraction