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

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.

Study Overview

• Status: Completed
• Conditions: Cataract
• Intervention / Treatment: Procedure: Phacoemulsification cataract surgery

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.

• Study Type: Observational
• Enrollment (Actual): 156

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients from a single ophthalmological center (Centro Hospitalar Baixo Vouga, Portugal) admitted for bilateral consecutive cataract surgery

Description

Inclusion Criteria:

• Patients having performed bilateral cataract surgery between 1st October 2012 and 24th April 2014 in a single ophthalmological center (Centro Hospitalar Baixo Vouga, Portugal)

Exclusion Criteria:

• Inadequate follow-up
• Incomplete medical records
• Previous or combined ocular surgery
• Manual extracapsular cataract extraction and not phacoemulsification
• Corneal sutures
• Implantation of any other IOL type different from Abbott Tecnis® 1-piece IOL (Abbott Laboratories Inc., Illinois, USA), ZCB00
• IOL implanted in the sulcus
• Intra or postoperative complication
• Post-operative best corrected visual acuity worse than 5/10
• Corneal astigmatism>3.00 D

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Main group; Patients having performed bilateral consecutive cataract surgery between 1st October 2012 and 24th April 2014 in a single ophthalmological center (Centro Hospitalar Baixo Vouga, Portugal).	Procedure: Phacoemulsification cataract surgery; Phacoemulsification of cataract (opacified lens) using clear corneal approach. Implantation of a intra-ocular lens in the capsular bag

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Second eye mean absolute error (mean of the absolute value of the prediction error)	6 weeks after date of cataract surgery

Secondary Outcome Measures

Outcome Measure	Time Frame
Percentage of second eyes with a post-operative refraction within ±0.50 D and ±1.00 D of the targeted refraction	6 weeks after date of cataract surgery

Collaborators and Investigators

• Sponsor: Centro Hospitalar do Baixo Vouga
• Investigators: Principal Investigator: Pedro Gil, MD, MSc, Centro Hospitalar do Baixo Vouga

Study record dates

Study Major Dates

• Study Start: June 1, 2014
• Primary Completion (Actual): July 1, 2014
• Study Completion (Actual): July 1, 2014

Study Registration Dates

• First Submitted: October 18, 2014
• First Submitted That Met QC Criteria: October 18, 2014
• First Posted (Estimate): October 21, 2014

Study Record Updates

• Last Update Posted (Estimate): October 21, 2014
• Last Update Submitted That Met QC Criteria: October 18, 2014
• Last Verified: October 1, 2014

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract
• Other Study ID Numbers: CHBaixoVouga

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No