Femtosecond Laser Versus Microkeratome in Creating Corneal Flaps in LASIK

Predictability of Corneal Flap Thickness in Lasik Using Femtosecod Laser in Comparison to Moria Microkeratome

Since the cornea is the main responsible for the refraction of the eye, as its refractive power is greater than 70% of the total refraction of the eye, so modification of its refractive properties are used to change the optical system of the eye. Hence, laser-assisted in situ keratomileusis has become the most commonly procedure used to correct the refractive errors of the eye. The most important step in laser-assisted in situ keratomileusis is the creation of the corneal flap, which its thickness may judge the whole outcome of the surgery . So trying to minimize the variation in the thickness of the resultant flap in comparison to what planned flap thickness preoperatively become our target.

Study Overview

• Status: Unknown
• Conditions: Femtosecond Laser in Comparison to Moria Microkeratome in Creating Corneal Flaps
• Intervention / Treatment: Device: anterior segment Ocular Coherence Tomography

Detailed Description

As laser-assisted in situ keratomileusis procedure started to use automated microkeratomes in creating corneal flaps since 1989, and science go on until United states Food and Drug Administration approved the IntraLase laser for flap creation in January 2000 femtosecond lasers work by emitting light pulses of short duration (10-15 s) at 1053 nm wavelength that cause photodisruption of the tissue with minimum collateral damage . This enables no blade incisions to be performed within the tissue at various patterns and depth with high precision.

Aim of the work To evaluate and compare the variation in corneal flap thickness created from use of a femtosecond laser and a MORIA microkeratome when making a 110-µm- and 90- µm thick corneal flap and to identify the potential factors that affect corneal flap thickness.

• Study Type: Observational
• Enrollment (Anticipated): 50

Contacts and Locations

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 40 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

population attending specialized eye centers

Description

Inclusion Criteria:

• Age 18-40 year
• Preoperative spherical refraction of -2.00 to -10.00D.
• Refractive cylinder of less than -3.00D.
• A stable refractive state for 2 years.
• An intraocular pressure (IOP) of <22 mm Hg.

Exclusion Criteria:

• A history of any systemic autoimmune disease.
• A history of diabetes.
• Other ophthalmic disorders.
• A history of ocular trauma and surgical history.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
femtosecond_laser; participants had there lasik corneal flap creation using femtosecond laser	Device: anterior segment Ocular Coherence Tomography; anterior segment OCT (Ocular Coherence Tomography) a device shows imaging of anterior segment of the eye and able to show corneal layers and measures its thickness.
moria_microkeratome; participants had there lasik corneal flap creation using moria microkeratome	Device: anterior segment Ocular Coherence Tomography; anterior segment OCT (Ocular Coherence Tomography) a device shows imaging of anterior segment of the eye and able to show corneal layers and measures its thickness.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
corneal flap thickness	measuring the corneal flap thickness in nanometers postoperatively by anterior segment OCT	7 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
uncorrected visual acuity	identifying uncorrected visual acuity postoperatively	7 days
best corrected visual acuity	identifying best corrected visual acuity postoperatively	7 days

Collaborators and Investigators

• Sponsor: Assiut University
• Investigators: Principal Investigator: GERGES F. YOUNAN, M.B.B.CH., Assiut University

Publications and helpful links

General Publications

• Zhang J, Zhang SS, Yu Q, Wu JX, Lian JC. Comparison of corneal flap thickness using a FS200 femtosecond laser and a moria SBK microkeratome. Int J Ophthalmol. 2014 Apr 18;7(2):273-7. doi: 10.3980/j.issn.2222-3959.2014.02.14. eCollection 2014.
• F.A.Guarnieri(ed.), Introduction, Corneal Biomechanics and Refractive Surgery, © Springer Science+Business Media New York 2015 ; 1: 1
• Solomon KD, Fernandez de Castro LE, Sandoval HP, Biber JM, Groat B, Neff KD, Ying MS, French JW, Donnenfeld ED, Lindstrom RL; Joint LASIK Study Task Force. LASIK world literature review: quality of life and patient satisfaction. Ophthalmology. 2009 Apr;116(4):691-701. doi: 10.1016/j.ophtha.2008.12.037.
• Sugar A, Rapuano CJ, Culbertson WW, Huang D, Varley GA, Agapitos PJ, de Luise VP, Koch DD. Laser in situ keratomileusis for myopia and astigmatism: safety and efficacy: a report by the American Academy of Ophthalmology. Ophthalmology. 2002 Jan;109(1):175-87. doi: 10.1016/s0161-6420(01)00966-6.
• Hsu SY, Chen HY, Chung CP. Analysis of actual corneal flap thickness and confounding factors between first and second operated eyes. Ophthalmic Surg Lasers Imaging. 2009 Sep-Oct;40(5):448-52. doi: 10.3928/15428877-20090901-02.
• Ortiz D, Alio JL, Pinero D. Measurement of corneal curvature change after mechanical laser in situ keratomileusis flap creation and femtosecond laser flap creation. J Cataract Refract Surg. 2008 Feb;34(2):238-42. doi: 10.1016/j.jcrs.2007.09.023.
• Reinstein DZ, Archer TJ, Gobbe M. The history of LASIK. J Refract Surg. 2012 Apr;28(4):291-8. doi: 10.3928/1081597X-20120229-01.
• Soong HK, Malta JB. Femtosecond lasers in ophthalmology. Am J Ophthalmol. 2009 Feb;147(2):189-197.e2. doi: 10.1016/j.ajo.2008.08.026. Epub 2008 Oct 18.
• Marino GK, Santhiago MR, Wilson SE. Femtosecond Lasers and Corneal Surgical Procedures. Asia Pac J Ophthalmol (Phila). 2017 Sep-Oct;6(5):456-464. doi: 10.22608/APO.2017163. Epub 2017 Jul 31.
• Ratkay-Traub I, Ferincz IE, Juhasz T, Kurtz RM, Krueger RR. First clinical results with the femtosecond neodynium-glass laser in refractive surgery. J Refract Surg. 2003 Mar-Apr;19(2):94-103. doi: 10.3928/1081-597X-20030301-03.

Study record dates

Study Major Dates

• Study Start (ANTICIPATED): April 1, 2018
• Primary Completion (ANTICIPATED): August 1, 2019
• Study Completion (ANTICIPATED): April 1, 2020

Study Registration Dates

• First Submitted: March 24, 2018
• First Submitted That Met QC Criteria: March 24, 2018
• First Posted (ACTUAL): March 30, 2018

Study Record Updates

• Last Update Posted (ACTUAL): March 30, 2018
• Last Update Submitted That Met QC Criteria: March 24, 2018
• Last Verified: March 1, 2018

More Information

Terms related to this study

• Keywords: laser; lasik; flap_thickness; femtosecond; moria; microkeratome
• Other Study ID Numbers: femtosecond_vs_microkeratome

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No