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3. MEDICAL AND HEALTH SCIENCES
To evaluate the validity of a keratometry (K)-independent method of estimating effective lens position (ELP) before phacoemulsification cataract surgery.
Institute of Eye Surgery, Whitfield Clinic, Waterford, Ireland.
Evaluation of diagnostic test or technology.
The anterior chamber diameter and corneal height in eyes scheduled for cataract surgery were measured with a rotating Scheimpflug camera. Corneal height and anterior chamber diameter were used to estimate the ELP in a K-independent method (using the SRK/T [ELPrs] and Holladay 1 [ELPrh] formulas).
The mean ELP was calculated using the traditional (mean ELPs 5.59 mm ± 0.52 mm [SD]; mean ELPh 5.63 ± 0.42 mm) and K-independent (mean ELPrs 5.55 ± 0.42 mm; mean ELPrh ± SD 5.60 ± 0.36 mm) methods. Agreement between ELPs and ELPrs and between ELPh and ELPrh were represented by Bland-Altman plots, with mean differences (± 1.96 SD) of 0.06 ± 0.65 mm (range −0.59 to +0.71 mm; P=.08) in association with ELPrs and −0.04 ± 0.39 mm (range −0.43 to +0.35 mm; P=.08) in association with ELPrh. The mean absolute error for ELPs versus ELPrs estimation and for ELPh versus ELPrh estimation was 0.242 ± 0.222 mm (range 0.001 to 1.272 mm) and 0.152 ± 0.137 mm (range 0.001 to 0.814 mm), respectively.
This study confirms that the K-independent ELP estimation method is comparable to traditional K-dependent methods and may be useful in post-refractive surgery patients.
Dooley, I., Charalampidou, S., Nolan, J., Loughman, J., Molloy, L., Beatty, S.: Estimation of Effective Lens Position Using a Method Independent of Preoperative Keratometry Readings. Journal of Cataract and Refractive Surgery, Vol.37, no.3, pp.506-12. 2011.