Pupil Centroid Shift Compensation in Photorefractive Keratectomy Candidates

Role of Pupil Centroid Shift Compensation on Lower and Higher Order Aberrations During Photorefractive Keratectomy: An Eye-to-Eye Study

patients who are candidates of PRK will be recruited in this intrasubject randomized clinical trial. Inclusion criteria are myopia or myopic astigmatism with refractive cylinder. Exclusion criteria were unstable refractive error, age less than 21 years old, corneal opacity, keratoconus, keratoconus suspects, residual corneal stromal thickness less than 350 µm, moderate or severe dry eye disease and any other ocular pathology other than refractive error. Complete eye exam will be performed preoperatively including: uncorrected distance visual acuity (UDVA), best spectacle corrected distance visual acuity (CDVA), cyclorefraction, slit lamp biomicroscopy, Goldmann applannation tonometry, dual scheimpflug tomography (Ziemmer), topography in mesopic condition accompanied by pupilometry and iris registration (Topolyzer Vario, Alcon Laboratories, Inc., Fort Worth, TX), and funduscopy with dilated pupil.

Surgical Technique The same surgeon (A.F.) will perform all surgeries. After installation of Tetracaine 1%, periorbital skin will be prepared with povidone iodine 5%. Iris registration will be performed in all eyes before epithelial removal. Ethylalcohol 20.0% into a 9.0 mm well for 20 seconds will be applied on the central cornea, and then the epithelium of the central 9.0 mm area will be removed by hockey knife. In the right eye of each patient PCS compensation will be turned on (PCS-On group) and in the left eye it will be turned off (PCS-Off group). Excimer laser ablation will be performed by Wavelight Allegretto EX500 (Alcon, Fort Worth, TX, USA). Selection of which eye to be first ablated will be done randomly. Randomization will be performed based on a computer software by a Biostatistician which produced the first eye to be operated. Static cyclotorsion compensation will be active in all eyes. The ablation profile will be wavefront-optimized in all cases.

Postoperative Course Postoperatively, chloramphenicol 0.5% eye drops and betamethasone 0.1% eye drops will be prescribed every 6 hours for 10 days. Thereafter, Fluorometholone 0.1% eye drops every 6 hours for 1 month and every 8 hours for the next month will be given. Follow-up examinations were scheduled at 1, 2, 3, 4, 7 and 15 days and 1, 2, 3, and 6 months postoperatively. After contact lens removal each follow-up examination includes the UDVA, manifest refraction, and IOP measurements as well as a slit lamp biomicroscopy. Corneal imaging with Galilei tomography, CDVA and cyclorefraction will be performed at the final follow-up examination 6 months postoperatively.

Study Overview

• Status: Unknown
• Conditions: Pupil Centroid Shift
• Intervention / Treatment: Procedure: The option for compensation of Pupil centroid shift was ON; Drug: installation of Tetracaine 1%; Procedure: Photorefractive keratectomy (PRK); Procedure: The option for compensation of Pupil centroid shift was OFF

• Study Type: Interventional
• Enrollment (Anticipated): 104
• Phase: Phase 2

Contacts and Locations

Study Locations

• Iran, Islamic Republic of
  • Tehran, Iran, Islamic Republic of
    • Recruiting
    • Ophthalmic Research Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 40 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• myopia
• myopic astigmatism

Exclusion Criteria:

• unstable refractive error, age less than 21 years old
• corneal opacity
• keratoconus, keratoconus suspects
• residual corneal stromal thickness less than 350 µm
• moderate or severe dry eye disease
• any other ocular pathology other than refractive error

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Single Group Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: The right eyes with compensation for Pupil centroid shift	Procedure: The option for compensation of Pupil centroid shift was ON; The option for compensation of Pupil centroid shift was ON; Drug: installation of Tetracaine 1%; installation of Tetracaine 1%; Procedure: Photorefractive keratectomy (PRK); periorbital skin will be prepared with povidone iodine 5%. Iris registration will be performed in all eyes before epithelial removal. Ethylalcohol 20.0% into a 9.0 mm well for 20 seconds will be applied on the central cornea, and then the epithelium of the central 9.0 mm area will be removed by hockey knife. Excimer laser ablation will be performed by Wavelight Allegretto EX500 (Alcon, Fort Worth, TX, USA)
Active Comparator: The left eyes without compensation for Pupil centroid shift	Drug: installation of Tetracaine 1%; installation of Tetracaine 1%; Procedure: Photorefractive keratectomy (PRK); periorbital skin will be prepared with povidone iodine 5%. Iris registration will be performed in all eyes before epithelial removal. Ethylalcohol 20.0% into a 9.0 mm well for 20 seconds will be applied on the central cornea, and then the epithelium of the central 9.0 mm area will be removed by hockey knife. Excimer laser ablation will be performed by Wavelight Allegretto EX500 (Alcon, Fort Worth, TX, USA); Procedure: The option for compensation of Pupil centroid shift was OFF; The option for compensation of Pupil centroid shift was OFF

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative refractive error	Snellen chart and subjective refraction	2 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Root Mean Square (RMS) of higher order aberration	wavefront analysis by galilei scan	6 months

Collaborators and Investigators

• Sponsor: Shahid Beheshti University of Medical Sciences

Study record dates

Study Major Dates

• Study Start (Anticipated): February 10, 2019
• Primary Completion (Anticipated): June 1, 2019
• Study Completion (Anticipated): July 1, 2019

Study Registration Dates

• First Submitted: February 2, 2019
• First Submitted That Met QC Criteria: February 13, 2019
• First Posted (Actual): February 18, 2019

Study Record Updates

• Last Update Posted (Actual): February 18, 2019
• Last Update Submitted That Met QC Criteria: February 13, 2019
• Last Verified: February 1, 2019

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Sensory System Agents; Anesthetics; Anesthetics, Local; Tetracaine
• Other Study ID Numbers: 97362

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No