Corneal Topography Asymmetry Indices Changes After Corneal Refractive Surgery

Tanta University

Status: Completed

Conditions: Myopia

Treatments: Other: Refractive surgery

Study type: Observational

Funder types: Other

Identifiers

NCT04589091

34081/9/20

Details and patient eligibility

About

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

Full 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.

Enrollment: 30 patients

Sex: All

Ages: 19 to 35 years old

Volunteers: No Healthy Volunteers

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

Trial design

30 participants in 2 patient groups

Group(1): Patient who underwent PRK

Treatment:

Other: Refractive surgery

Group(2): Patient underwent LASIK

Treatment:

Other: Refractive surgery