NCT04684888

Femto-flap Versus SBK Flap,Predictability and Variability

Comparison of Corneal Flap Thickness Using Visumax Femto-Lasik With SubBowman Keratomileusis (SBK) Microkeratome

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 50 (actual)
• Sponsor: Suzan A Rattan · Academic / Other
• Sex: All
• Age: 20 Years – 38 Years
• Healthy volunteers: Accepted

Summary

Laser Insitu keratomileusis (LASIK) has become the most popular procedure for refractive error correction. Lasik flap creation is the first and critical step during LASIK surgery because of its consensual effect on a residual stromal bed, corneal biomechanics, and hence the future risk of ectasia⁴.In the current study, we compared the Visumax FSL flap thickness predictability, accuracy, and variability with the flap created by single-use Moria SBK microkeratome.

Detailed description

Flap creation techniques have evolved from the old manual procedure of mechanical microkeratome to the automated one with the use of microkeratome and more recently to Femto-laser procedure using a variety of machines. Authors have reported that the primary vision nearly the same despite the different methods of flap creation in the first 6 months post LASER vision correction. Others have reported that a thinner flap is associated with better primary vision and refractive outcomes. SBK (Sub Bowman Keratomileusis), is a procedure in which the Lasik flap is thinner, and has the advantage of leaving a sufficient stromal bed for safer excimer Laser ablation. There are five types of femtosecond Laser that were already approved currently for Lasik flap creation. The Zeiss (Visumax FSL ) which has been used in the current study uses 1043 nm, a repetition rate of 500 kHz, and 220-580 femtoseconds pulse duration. Each laser pulse produces micro-photo disruption in the tissue, contiguous few microns sized photo disruptions will create a continuous cut in the corneal tissue at precise preset position and depth. In the current study, the Visumax flap thickness predictability, accuracy, and variability were compared with the flap created by a single-use Moria SBK microkeratome.

Conditions

• Refractive Errors
• Refractive Surgery

Interventions

Type	Name	Description
PROCEDURE	Visumax Femto-flap	Under topical anesthesia \[Tetracaine eye drop 0.5%\]. A-90 µm thick flap was done by using Visumax femtosecond laser. The flap hinge was set to be nasally placed. A nasal-hinge flap with 90 µm thickness, 8.8 mm flap diameter, and 90º side cut angles were created with 500 kHz Visumax FSL, 160 nJ energy \[Carl Zeiss, Meditec, Germany\]. The sphero- cylindrical refractive corrections with optical zone 6.5 mm and ablation zone 8.0 mm were done by excimer laser operating system \[Carl Zeiss, Meditec, MEL 90, Germany\]. Automatic iris registration and pupil-tracking system were activated before photoablation. The patient's eyes were examined postoperatively on a slit-lamp biomicroscope and all treatments that were given for home use have been explained in terms of frequency of instillation, possible side effects, and benefits before discharging them on the same day. Follow up visits were scheduled clearly on printed patients' discharging cards.
PROCEDURE	Sub Bowman's keratomileusis (SBK)-flap	Under topical anesthesia \[Tetracaine eye drop 0.5%\] .A-90µm flaps done using Maria one use plus SBK mechanical microkeratome with a nasal located hinge. The sphero- cylindrical refractive corrections with optical zone 6.5 mm and ablation zone 8.0 mm were done by excimer laser operating system \[Carl Zeiss, Meditec, MEL 90, Germany\]. Automatic iris registration and pupil-tracking system were activated before photoablation. The patient's eyes were examined postoperatively on a slit-lamp biomicroscope and all treatments that were given for home use have been explained in terms of the frequency of instillation, possible side effects, and benefits before discharging them on the same day. Follow up visits were scheduled clearly on printed patients' discharging cards .

Timeline

• Start date: 2019-01-01
• Primary completion: 2020-09-30
• Completion: 2021-05-30
• First posted: 2020-12-28
• Last updated: 2021-07-20

Locations

1 site across 1 country: Iraq