Orthoptic Changes Following Photorefractive Keratectomy

January 19, 2011 updated by: Shahid Beheshti University of Medical Sciences
Purpose: To detect orthoptic changes in patients undergoing photorefractive keratectomy (PRK). Method: This interventional case series was performed on 297 eyes of 150 patients who were candidates for PRK. Complete ophthalmic evaluations focusing on orthoptic examinations were performed before and 3 months after PRK. Results: Before PRK, two (1.3%) patients had esotropia that remained unchanged postoperatively. However, 3 (2%) patients had distance exotropia preoperatively which improved after PRK. Of 12 cases (8%) with preoperative exotropia at near, 3 (2%) cases became orthophoric. Six patients (4%) developed postoperative near exotropia. A significant reduction in means of convergence and divergence amplitudes (P<0.001) and a meaningful increase in mean of near point of convergence (NPC) (P<0.006) were noticed after PRK. A reduction of ≥10 PD in convergence amplitude and ≥5 PD in divergence amplitude were detected in 10 and 5 patients, respectively. Four patients had an preoperative NPC>10 cm which was not changed by the surgery. Out of 9 (6%) patients with baseline stereopsis >60 seconds of arc, 2 (1.33%) cases showed an improvement in stereopsis following PRK. None of the patients complained of postoperative diplopia. Conclusion: Eye deviation in patients undergoing PRK may improve or remain unchanged after operation and postoperative deviations can develop following this surgery. Diminishing of fusional amplitude and increasing of NPC as well as improving of stereopsis may also happen after PRK. Therefore, a preoperative orthoptic examination in patients with any concerning histories and/or motility issues on routine exam is recommended before performing PRK.

Study Overview

Status

Status

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Completed

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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Study Type

Study Type

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Interventional

Phase

Phase

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  • Phase 3

Contacts and Locations

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Study Locations

Participation Criteria

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Eligibility Criteria

Eligibility Criteria

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Ages Eligible for Study

18 years to 59 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

>18 yrs / refractive errors / with consent

Exclusion Criteria:

< 18 / corneal opacity - keratoconus

Dry eye / diabetes / collages vacuolar disease

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

  • Primary Purpose: Supportive Care
  • Allocation: Non-Randomized
  • Interventional Model: Single Group Assignment

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
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.
Experimental: Kerato refractive Surgery
Procedure: Kerato refractive Surgery
This interventional case series was performed on 297 eyes of 150 patients who were candidates for PRK. Complete ophthalmic evaluations focusing on orthoptic examinations were performed before and 3 months after PRK.

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
Measure Description
Time Frame
orthoptic changes
Time Frame: before and after KRS
Prism / (deviation)
before and after KRS

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
Measure Description
Time Frame
VA , Streopsis , deviation , fusion , NPC
Time Frame: before and after KRS
Snellen , Titmus, prism, ruler
before and after KRS

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.
Shahid Beheshti University of Medical Sciences

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: zhaleh rajavi, Assistant Professor, Imam Hossein medical center

Study record dates

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Study Major Dates

Study Start

Study Start

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April 1, 2008

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.
January 1, 2009

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.
April 1, 2009

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).
January 19, 2011

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.
January 19, 2011

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.
January 20, 2011

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.
January 20, 2011

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.
January 19, 2011

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.
April 1, 2008

More Information

Terms related to this study

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.
  • 8659 (Other Identifier: Fred Hutch/University of Washington Cancer Consortium)

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