Comparisons Of Objective And Subjective Refraction Measurements In Patients With Moderate And Severe Keratoconus
Published 2026 - 44th Congress of the ESCRS
Reference: POCOR364 | Type: Free paper | DOI: 10.82333/feh4-pn68
Authors: A/Prof. Masoud Khorrami-Nejad* 1 , A/Prof. Hesam Hashemian 1 , Ms Zeinab Qasim Radhi 1 , A/Prof. Foroozan Narooie-Noori 1 , Mr Reza Yousefi 1
1Tehran University of Medical Sciences,Tehran,Iran, Islamic Republic Of
Purpose
To compare objective and subjective refraction measurements in patients with moderate to severe keratoconus.
Setting
The study was conducted at Farabi Eye Hospital, a tertiary referral ophthalmic center in Tehran, Iran.
Methods
In this observational cross-sectional study 107 eyes of 107 patients (26.0 ± 7.03 years old) with moderate to severe keratoconus were recruited. Objective refraction was performed using an autorefractor and subjective refraction was obtained by an optometrist. Spherical equivalent (SE), sphere, cylinder, J0, and J45 were compared between techniques, subsequently.
Results
Strong positive correlations were found between measurement techniques for SE (r=0.790), sphere (r=0.836), and cylinder (r=0.571) (all, P<0.001). Furthermore, our results showed weaker positive correlations for J0 (r=0.387, P<0.001) and J45 (r=0.206, P=0.035). On average, objective refraction yielded more negative values than subjective refraction for SE (-2.31 D difference, P<0.001), sphere (-1.71 D, p<0.001) and cylinder (-1.21 D, P<0.001). No statistically significant differences were found for J0 and J45 between techniques.
Conclusions
In moderate-severe keratoconus, objective refraction demonstrates good correlation but yields more negative values compared to subjective refraction for spherical and regular astigmatism parameters. Measurement agreement appears weaker for irregular astigmatism. A combination approach utilizing objective data supplemented by subjective refinement may provide the most accurate refraction.