Corneal Topography Asymmetry Indices Changes After Corneal Refractive Surgery

• ClinicalTrials.gov Identifier: NCT04589091
• Recruitment Status: Completed
• First Posted: October 19, 2020
• Last Update Posted: February 8, 2022
• Sponsor: Tanta University
• Information provided by (Responsible Party): Dina Tadros, Tanta University

Study Description

Brief Summary:

To evaluate the changes that occur in the corneal indices after corneal refractive surgery either PRK or LASIK.

Condition or disease	Intervention/treatment
Myopia	Other: Refractive surgery

Detailed Description:

Retrospectively review the medical records of all patients who underwent refractive surgery referred from the out-patient clinic of Tanta University hospital between September 2015 and September 2020 .

Data collection will include:

Preoperative and postoperative Evaluation: Age, sex, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest and cycloplegic refraction, Slit lamp biomicroscopy, fundus examination.

Data of Corneal Tomography keratometric using Scheimpflug camera (Pentacam Oculus- Germany) :that includes the following indices

1. Average keratometric value (K mean) in diopters
2. Maximum simulated keratometry (Kmax) in diopters
3. Index of Surface Variance (ISV) in microns
4. Index of Vertical Asymmetey (IVA) in microns
5. Radii Minimum (R min) in microns
6. Index of height asymmetry (IHA) in microns
7. Index of height decantation (IHD) in microns
8. Aberration coefficient (ABR)

The data of the pentacam will be collected pre-operative and analyzed at 1 month, 3 months and 6 months with recording of the complications.

Study Design

• Study Type: Observational
• Actual Enrollment: 30 participants
• Observational Model: Other
• Time Perspective: Retrospective
• Official Title: Corneal Topography Asymmetry Indices Changes After Corneal Refractive Surgery
• Actual Study Start Date: April 13, 2021
• Actual Primary Completion Date: October 30, 2021
• Actual Study Completion Date: January 30, 2022

Groups and Cohorts

Group/Cohort	Intervention/treatment
Group(1): Patient who underwent PRK	Other: Refractive surgery; Refractive surgery for correction of error of refraction
Group(2): Patient underwent LASIK	Other: Refractive surgery; Refractive surgery for correction of error of refraction

Outcome Measures

Primary Outcome Measures :

1. To evaluate the changes that occur in the corneal indices after corneal refractive surgery either PRK or LASIK. [ Time Frame: 6 months ]

   Using the results of measurements of Scheimpflug camera (Pentacam Oculus- Germany) :that includes the following indices

   1. Average keratometric value (K mean) in diopters
   2. Maximum simulated keratometry (Kmax) in diopters
   3. Index of Surface Variance (ISV) in microns
   4. Index of Vertical Asymmetey (IVA) in microns
   5. Radii Minimum (R min) in microns
   6. Index of height asymmetry (IHA) in microns
   7. Index of height decantation (IHD) in microns
   8. Aberration coefficient (ABR)

   The numbers from preoperative records will be compared with postoperative records after the refractive surgery is done . All the values will be expressed as mean ± standard deviation and the data will be analyzed as 1 months, 3 months and 6 months after surgery

Eligibility Criteria

• Ages Eligible for Study: 19 Years to 35 Years (Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No
• Sampling Method: Non-Probability Sample

Study Population

We will retrospectively review the medical records of all patients who underwent refractive surgery referred from the out-patient clinic of Tanta University hospital between September 2015 and September 2020

Criteria

Inclusion Criteria:

• Patients who underwent refractive surgery either PRK, LASIK with age between 19 and 35 years old

Exclusion Criteria:

• Kertoconus.

  • Corneal scarring.
  • Previous corneal infections.
  • Minimum corneal thickness at the thinnest location less than 400 µm.
  • History of uveitis or ocular allergy.
  • Pre-existing glaucoma.
  • Data not available

Contacts and Locations

Locations

Egypt

Tanta University Hospital

Tanta, El-Garbeia, Egypt, 31515

Sponsors and Collaborators

Tanta University

More Information

Publications of Results:

Bailey MD, Zadnik K. Outcomes of LASIK for myopia with FDA-approved lasers. Cornea. 2007 Apr;26(3):246-54.

Sridhar MS, Rao SK, Vajpayee RB, Aasuri MK, Hannush S, Sinha R. Complications of laser-in-situ-keratomileusis. Indian J Ophthalmol. 2002 Dec;50(4):265-82. Review.

Mohammadi SF, Nabovati P, Mirzajani A, Ashrafi E, Vakilian B. Risk factors of regression and undercorrection in photorefractive keratectomy: a case-control study. Int J Ophthalmol. 2015 Oct 18;8(5):933-7. doi: 10.3980/j.issn.2222-3959.2015.05.14. eCollection 2015.

Belin MW, Ambrósio R Jr. Corneal ectasia risk score: statistical validity and clinical relevance. J Refract Surg. 2010 Apr;26(4):238-40. doi: 10.3928/1081597X-20100318-01.

• Responsible Party: Dina Tadros, Lecturer of ophthalmology , Tanta University Hospital, Tanta University
• ClinicalTrials.gov Identifier: NCT04589091
• Other Study ID Numbers: 34081/9/20
• First Posted: October 19, 2020
• Last Update Posted: February 8, 2022
• Last Verified: February 2022

Individual Participant Data (IPD) Sharing Statement:

• Plan to Share IPD: Yes
• Supporting Materials: Study Protocol
• Time Frame: 3 months
• Access Criteria: Link

• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: No

Additional relevant MeSH terms:

Myopia; Refractive Errors; Eye Diseases