NCT02270879

Multi-formula Optimization of Second Eye Refinement According to Direction of the Prediction Error of the First Eye

• Status: Completed
• Phase: —
• Study type: Observational
• Enrollment: 156 (actual)
• Sponsor: Centro Hospitalar do Baixo Vouga · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

Prediction errors for the first (PE1) and second eyes (PE2) were obtained in the intra-ocular lens power calculation for 4 formulae (HofferQ, SRK II, SRK/T and Holladay 1). The optimal correction factor for each formula was determined as the one resulting in the lowest mean absolute error. A similar analysis was performed in the negative and positive PE1 subgroups.

Detailed description

Retrospective case series study. A retrospective chart review was conducted, which included demographics (age and gender) and several parameters for both the first and second eyes: surgery date, axial length, keratometric corneal power in 2 meridians, predicted intra-ocular lens (IOL) power recommended for plano target in each formulae (HofferQ, SRK II, SRK/T and Holladay 1), implanted IOL power, predicted post-operative refraction for the implanted IOL for the 4 formulae, observed post-operative refraction in spherical equivalent and post-operative best corrected visual acuity. The prediction error was calculated for the first eye (PE1) as the difference between the observed post-operative refraction in spherical equivalent and the predicted post-operative refraction by the IOL Master for the implanted IOL. This was obtained for the 4 formulae. The prediction error for the second eye (PE2) was obtained in a similar fashion. The optimal partial adjustment for second eye refinement was obtained subtracting a portion of the PE1 from the PE2 (PE2-xPE1, where 0≤x≤1) for the 4 formulae. The optimal correction factor was determined for all formulae by using an array of different proportions of PE1 that were applied to the second eye. The values ranged from 10% to 100%, with increments of 10% each.

Conditions

• Cataract

Interventions

Type	Name	Description
PROCEDURE	Phacoemulsification cataract surgery	Phacoemulsification of cataract (opacified lens) using clear corneal approach. Implantation of a intra-ocular lens in the capsular bag

Timeline

• Start date: 2014-06-01
• Primary completion: 2014-07-01
• Completion: 2014-07-01
• First posted: 2014-10-21
• Last updated: 2014-10-21