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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.
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.
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| placido-based topographer (wavelight allegro topolyzer vario) and scheimpflug -based (Oculus Pentacam ) | Device | An informed written consent will be obtained from all patients that will be included in this study. Patients in this study will undergo pentacam and topolyzer examination to asses corneal high order aberrations before LASIK procedure. Patients will be assigned to undergo LASIK. Follow up pentacam and topolyzer examination will be done 3 months after LASIK. |
| Measure | Description | Time Frame |
|---|---|---|
| Agreement between placido-based topographer (wavelight allegro topolyzer vario) and scheimpflug -based (pentacam) | Agreement between placido-based topographer (wavelight allegro topolyzer vario) and scheimpflug -based (pentacam) regard measuring corneal high order aberrations before and after LASIK. | Before LASIK and 3 months after LASIK |
| Measure | Description | Time Frame |
|---|---|---|
| Changes in high order aberrations after LASIK. | Changes in high order aberrations after LASIK using pentacam and topolyzer | Before LASIK and 3 months after LASIK |
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Inclusion Criteria:
Exclusion Criteria:
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Patients who will undergo LASIK
| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Naglaa MA Abdelmohsen, MD | Contact | +201095459579 | dr.naglaa15@gmail.com |
| Name | Affiliation | Role |
|---|---|---|
| Tarek A Ali, Professor | Assiut University | Study Director |
| Khaled A Mohamed, Assistant prof | Assiut University | Study Director |
| Islam M Goda, Lecturer |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Naglaa Moustafa | Asyut | Egypt |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 36927406 | Background | Salman A, Kailani O, Ghabra M, Omran R, Darwish TR, Shaaban R, Ibrahim H, Alhaji H, Khalil H. Corneal higher order aberrations by Sirius topography and their relation to different refractive errors. BMC Ophthalmol. 2023 Mar 16;23(1):104. doi: 10.1186/s12886-023-02841-4. | |
| 25028356 | Background | Little JA, McCullough SJ, Breslin KM, Saunders KJ. Higher order ocular aberrations and their relation to refractive error and ocular biometry in children. Invest Ophthalmol Vis Sci. 2014 Jul 15;55(8):4791-800. doi: 10.1167/iovs.13-13533. |
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| Assiut University |
| Study Director |
| 36862309 | Background | Ning R, Huang X, Jin Y, Lei CS, Ma X, Xu S, Xiahou J, Savini G, Schiano-Lomoriello D, Wang X, Zhou X, Huang J. Corneal Higher-Order Aberrations Measurements: Precision of SD-OCT/Placido Topography and Comparison with a Scheimpflug/Placido Topography in Eyes After Small-Incision Lenticule Extraction. Ophthalmol Ther. 2023 Jun;12(3):1595-1610. doi: 10.1007/s40123-023-00693-1. Epub 2023 Mar 2. |
| 36578031 | Background | Lou W, Du W, Jin H, Hu Y. Comparison of anterior corneal aberrations measured by Scheimpflug and Placido Disc System for myopes. BMC Ophthalmol. 2022 Dec 28;22(1):512. doi: 10.1186/s12886-022-02753-9. |
| Background | Miret JJ, Rojas E, Camps VJ, Garcia C, Caballero MT, MartÃn B, et al. Understanding the Real Effect of the High-Order Aberrations after Myopic Femto-Lasik. Optics. 2022;3(4):384-99. |
| 36983581 | Background | 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. |
| 30713018 | Background | 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. |
| 27163620 | Background | Ortiz-Toquero S, Rodriguez G, de Juan V, Martin R. Repeatability of Wavefront Aberration Measurements With a Placido-Based Topographer in Normal and Keratoconic Eyes. J Refract Surg. 2016 May 1;32(5):338-44. doi: 10.3928/1081597X-20160121-04. |