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

October 18, 2014 updated by: Pedro Gil, Centro Hospitalar do Baixo Vouga
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

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
156

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Retrospective

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Second eye mean absolute error (mean of the absolute value of the prediction error)
Time Frame: 6 weeks after date of cataract surgery
6 weeks after date of cataract surgery

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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
Time Frame: 6 weeks after date of cataract surgery
6 weeks after date of cataract surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Centro Hospitalar do Baixo Vouga

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Pedro Gil, MD, MSc, Centro Hospitalar do Baixo Vouga

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2014

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 1, 2014

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2014

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 18, 2014

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 18, 2014

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 21, 2014

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 21, 2014

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 18, 2014

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2014

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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