Comparison of Cross-cylinder and Conventional Photorefractive Keratectomy(PRK) in Correcting Medium-high Astigmatism

NCT00663923 | Completed Phase 3 Results DMC

• 1 other identifier: 86-43
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this study is to determine whether cross-cylinder approach is more effective than routine method in laser correction of astigmatism.

Conditions

Astigmatism

Keywords

Excimer Laser; photorefractive keratectomy; astigmatism

Outcome Measures

Primary Outcomes (1)

• Correction of Astigmatism

  It shows the result of correction of astigmatism .In compound myopic astigmatism the meridians of maximum and minimum power are both too strong.So both line images fall short of the retina.It is measured by refraction(using autorefractor).Diopter is a unit of measurement of the optical power of any refracting surface ,which is reciprocal of the focal length measured in meters.

  six months after surgery

Secondary Outcomes (4)

• Higher Order Aberrations

  six months postoperative

• Corrected Distance Visual Acuity(CDVA)

  six months

• Uncorrected Distance Visual Acuity (UCDVA)

  six months

• Surgically Induced Astigmatism

  six months after surgery

Study Arms (2)

cross-cylinder

EXPERIMENTAL

In this technique the laser is programmed with the axis and amount of cylinder,so that the steepest meridian is flattened with central cylindrical ablation and the flattest meridian steepens with paracentral ablation

Procedure: photorefractive keratectomy (PRK)

single

ACTIVE COMPARATOR

In this technique ,cylinder is treated only on one meridian by performing an elliptical ablation to to flatten the steeper meridian to match the flatter meridian.

Procedure: photorefractive keratectomy (PRK)

Interventions

photorefractive keratectomy (PRK) PROCEDURE

comparison of PRK by cross-cylinder approach in one eye and conventional (single) method in the other eye for laser correction of astigmatism

Also known as: photoastigmatic keratectomy

cross-cylinder; single

Eligibility Criteria

• Age: 20 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• \>20 years of age
• refractive stability for at least one year
• regular and symmetric astigmatism of \>1.5 diopters

You may not qualify if:

• corneal thickness\<470 microns
• keratoconus or suspected keratoconus
• active ocular disease and systemic collagen disease

Sponsors & Collaborators

• Tabriz University: lead

Study Sites (1)

Nikookari eye hospital

Tabriz, East Azerbaijan Province, 5154645395, Iran

Location

MeSH Terms

Conditions

Astigmatism

Interventions

Photorefractive Keratectomy

Condition Hierarchy (Ancestors)

Refractive Errors; Eye Diseases

Intervention Hierarchy (Ancestors)

Corneal Surgery, Laser; Laser Therapy; Therapeutics; Ablation Techniques; Surgical Procedures, Operative; Keratectomy; Refractive Surgical Procedures; Ophthalmologic Surgical Procedures

Results Point of Contact

• Title: Mohammad R sedghipour,MD
• Organization: Tabriz University of Medical Sciences

sedghipm@yahoo.com

+98 411 3306619

Study Officials

• Mohammad R Sedghipoor, MD

  Ophthalmology Department, Tabriz University of medical Sciences

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: Yes
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 18, 2008
• First Posted: April 22, 2008
• Study Start: November 1, 2007
• Primary Completion: June 1, 2009
• Study Completion: December 1, 2009
• Last Updated: March 13, 2012
• Results First Posted: December 30, 2011

Record last verified: 2012-03

Locations

IR (1)