Clinical trial NCT06278220: Scheimpflug Versus Placido-disc System in Evaluation of Corneal Higher-Order Aberrations
Official title: Scheimpflug Versus Placido-disc System in Evaluation of Corneal Higher-Order Aberrations Before and After LASIK
Study type: OBSERVATIONAL
Overall status: NOT_YET_RECRUITING
Conditions: Corneal Higher-order Aberrations
Keywords: higher-order aberrations
Pentacam
Topolyzer
LASIK
Lead sponsor: Assiut University
Sponsor class: OTHER
First posted: 2024-02-26
Enrollment: 36
Sex: ALL
Minimum age (years): 18
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: no
Observational model: OTHER
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients who will undergo LASIK

Brief summary: Aim of work:

To assess the agreement between placido-based topographer (wavelight allegro topolyzer vario) and scheimpflug -based (Oculus Pentacam ) regard measuring corneal higher order aberrations before and after LASIK.

Detailed description: Higher-order aberrations (HOAs) are small optical irregularities of the eye, which can have an impact on the quality of the retinal image. In contrast to lower order aberrations, these errors cannot be corrected with regular spectacles and most contact lenses. Additionally, HOAs are responsible for an array of visual symptoms including dysphotopsia, glare, as well as a reduction in contrast sensitivity. The cornea accounts for approximately 90% of ocular aberrations.Advances and breakthroughs in wavefront aberration measurement technology can help clinicians to better understand and manage corneal higher-order aberrations (HOAs), especially for the preoperative planning of corneal refractive surgery and cataract surgery.A recent study has shown that corneal HOAs can be a sensitive parameter to differentiate early keratoconus from normal eyes. Furthermore, corneal aberrations have been widely used to evaluate dry eye and orthokeratology.LASIK surgery is widely used in the correction of refractive errors It is well known that LASIK surgery induces high-order aberrations (HOA) .The main eye element involved in the generation of such aberrations is the first corneal surface. Currently, devices based on Placido-disc, Hartmann- Shack, ray tracing, or Scheimpflug are routinely used in clinical aberration measurement. Of which Pentacam is one of common instruments that can only measure corneal aberration (including anterior and posterior corneal surface) based on Scheimpflug technology. Also Allegro Topolyzer is a Placido-based topographer that can measure anterior corneal higher order aberrations (HOAs). A better understanding of the agreement of device measurements can provide clinicians with useful information for measuring, correcting, and monitoring aberrations around refractive and cataract surgery. Investigators , therefore, aimed to study the agreement between the two instruments in anterior corneal aberration measurement.

Eligibility criteria: Inclusion Criteria:

* Patients with refractive errors from +6 diopters to -8 diopters sphere and up to -6diopters cylinder.

Exclusion Criteria:

* Patients with systemic diseases such as diabetes.
* keratoconus or keratoconus suspect, amblyopic eyes.
* Patients with best corrected visual acuity (BCVA) not achieving 20/25.
* glucoma
* Previous ocular surgeries or trauma.

Primary outcomes:
measure: Agreement between placido-based topographer (wavelight allegro topolyzer vario) and scheimpflug -based (pentacam)
timeFrame: Before LASIK and 3 months after LASIK
Secondary outcomes:
measure: Changes in high order aberrations after LASIK.
timeFrame: Before LASIK and 3 months after LASIK
Other outcomes:
Locations:
city: Assiut
country: Egypt
facility: Naglaa Moustafa
Study officials:
affiliation: Assiut University
name: Tarek A Ali, Professor
role: STUDY_DIRECTOR
affiliation: Assiut University
name: Khaled A Mohamed, Assistant prof
role: STUDY_DIRECTOR
affiliation: Assiut University
name: Islam M Goda, Lecturer
role: STUDY_DIRECTOR
References:
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citation: Mai EL, Chang CK, Lee CY, Lian IB, Chao CC. Higher-Order Aberrations of Topography-Guided LASIK and Wavefront-Optimized LASIK in High- and Low-Myopic Eyes: A Non-Randomized Controlled Trial. J Pers Med. 2023 Feb 24;13(3):399. doi: 10.3390/jpm13030399.
citation: Piccinini AL, Golan O, Hafezi F, Randleman JB. Higher-order aberration measurements: Comparison between Scheimpflug and dual Scheimpflug-Placido technology in normal eyes. J Cataract Refract Surg. 2019 Apr;45(4):490-494. doi: 10.1016/j.jcrs.2018.11.015. Epub 2019 Jan 31.
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