Clinical trial NCT02270879: Multi-formula Optimization of Second Eye Refinement According to Direction of the Prediction Error of the First Eye
Official title: Multi-formula Optimization of Second Eye Refinement According to Direction of the Prediction Error of the First Eye
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Cataract
Lead sponsor: Centro Hospitalar do Baixo Vouga
Sponsor class: OTHER
First posted: 2014-10-21
Enrollment: 156
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients from a single ophthalmological center (Centro Hospitalar Baixo Vouga, Portugal) admitted for bilateral consecutive cataract surgery

Brief 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.

Eligibility criteria: 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

Primary outcomes:
measure: Second eye mean absolute error (mean of the absolute value of the prediction error)
timeFrame: 6 weeks after date of cataract surgery
Secondary outcomes:
measure: Percentage of second eyes with a post-operative refraction within ±0.50 D and ±1.00 D of the targeted refraction
timeFrame: 6 weeks after date of cataract surgery
Other outcomes:
Locations:
Study officials:
affiliation: Centro Hospitalar do Baixo Vouga
name: Pedro Gil, MD, MSc
role: PRINCIPAL_INVESTIGATOR
References: