Corneal Topography Asymmetry Indices Changes After Corneal Refractive Surgery

Myopia Clinical Trial

Official title:

Corneal Topography Asymmetry Indices Changes After Corneal Refractive Surgery

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04589091
• Other study ID #: 34081/9/20
• Status: Completed
• Start date: April 13, 2021
• Est. completion date: January 30, 2022

Study information

• Verified date: February 2022
• Source: Tanta University
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

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

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 30
• Est. completion date: January 30, 2022
• Est. primary completion date: October 30, 2021
• Accepts healthy volunteers: No
• Gender: All
• Age group: 19 Years to 35 Years

Eligibility

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

Related Conditions & MeSH terms

• Myopia

Intervention

Other:
• Refractive surgery
Refractive surgery for correction of error of refraction

Locations

Country	Name	City	State
Egypt	Tanta University Hospital	Tanta	El-Garbeia

Sponsors (1)

Lead Sponsor	Collaborator
Tanta University

Country where clinical trial is conducted

Egypt, 

References & Publications (4)

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

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. — View Citation

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. eCollect — View Citation

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. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	To evaluate the changes that occur in the corneal indices after corneal refractive surgery either PRK or LASIK.	Using the results of measurements of Scheimpflug camera (Pentacam Oculus- Germany) :that includes the following indices; Average keratometric value (K mean) in diopters; Maximum simulated keratometry (Kmax) in diopters; Index of Surface Variance (ISV) in microns; Index of Vertical Asymmetey (IVA) in microns; Radii Minimum (R min) in microns; Index of height asymmetry (IHA) in microns; Index of height decantation (IHD) in microns; 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	6 months