Accuracy of LASIK Flaps Created With the LenSx® Femtosecond Laser - A Pilot Study

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the thickness accuracy of Laser-assisted in situ keratomileusis (LASIK) flaps created with the LenSx® Laser.

Official Title
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Accuracy of LASIK Flaps Created With the LenSx® Femtosecond Laser - A Pilot Study

Conditions
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Hyperopia, Myopia

Intervention / Treatment
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* Device: Femtosecond Laser System
* Procedure: LASIK surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosed with myopia or hyperopia and eligible for femtosecond laser initiated LASIK surgery; Best corrected visual acuity (BCVA) correctable to at least 20/25 in each eye; If contact lens wearer, willing to discontinue contact lens wear prior to screening procedures; Willing and able to return for ALL scheduled follow-up examinations; Willing and able to provide written informed consent; Eligible for bilateral LASIK procedures to be done on the same day; Other protocol-specified inclusion criteria may apply. Exclusion Criteria: Previous corneal surgery, corneal lesions that will impede laser treatment, corneal edema, hypotony, glaucoma, existing corneal implant, or keratoconus; Known sensitivity to planned study concomitant medications; Participation in any other ophthalmic drug or device clinical study for 30 days prior to or during the time of participation in this study; Irregular astigmatism, based on the Investigator's judgement; Pregnant, lactating or planning to become pregnant during the course of the study; Other protocol-specified exclusion criteria may apply.

Ages Eligible for Study
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Minimum Age: 22 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: LenSx<br>LASIK surgery in both eyes using LenSx® Femtosecond Laser System | Device: Femtosecond Laser System<br>* Used for the creation of a corneal flap in patients undergoing LASIK surgery<br>* Other names: LenSx®;Procedure: LASIK surgery<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Flap Thickness Accuracy Within the Central Zone at Month 3 Postoperative | Flap thickness was assessed by optical coherence tomography (OCT) and averaged from 3 separate scans. Flap thickness accuracy was defined as the mean difference between the achieved and desired (desired subtracted from achieved) flap thickness. A positive number represents a postoperative flap thickness that is thicker than the expected flap thickness and vice versa for a negative number. Each eye contributed separately to the analysis. | Month 3 postoperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Flap Thickness Accuracy Within the Central Zone at Month 1 Postoperative | Flap thickness was assessed by OCT and averaged from 3 separate scans. Flap thickness accuracy was defined as the mean difference between the achieved and desired (desired subtracted from achieved) flap thickness. A positive number represents a postoperative flap thickness that is thicker than the expected flap thickness and vice versa for a negative number. Each eye contributed separately to the analysis. | Month 1 postoperative | 
| Flap Thickness Precision Within the Central Zone at Month 1 and Month 3 Postoperative | Flap thickness was assessed by OCT and averaged from 3 separate scans. Flap thickness precision (variability of the achieved flap thickness) was defined as the standard deviation of the flap thickness measurement. Each eye contributed separately to the analysis. | Month 1, Month 3 postoperative | 
| Ease of Flap Dissection at Day 0, Operative Day | Ease of flap dissection (ease of lifting the flap during surgery) was assessed on a scale from 0 to 5 where 0 = Unable to lift flap and 5 = Able to lift flap without any resistance using blunt instrument. Each eye contributed separately to the analysis. | Day 0, operative day | 
| Stromal Bed Quality at Day 0, Operative Day | Stromal bed quality was assessed by the investigator on a roughness scale from 0 to 5 where 0 = Very rough surface and 5 = Very smooth surface. Each eye contributed separately to the analysis. | Day 0, operative day | 
| Opaque Bubble Layer (OBL) at Day 0, Operative Day | Opaque bubble layer was assessed by the investigator during the surgery on a scale from 0 to 5 where 0 = No OBL and 5 = 100% OBL in the stromal bed area. Each eye contributed separately to the analysis. | Day 0, operative day | 
| Uncorrected Distance Visual Acuity (UCDVA) at Month 1 and Month 3 Postoperative | UCDVA (measurement of uncorrected (without spectacles or other visual corrective devices) distance visual acuity) was assessed at a distance of 6 meters or 20 feet using a standard Snellen eye chart, both monocularly and binocularly, and reported categorically as a percentage of eyes analyzed. | Month 1, Month 3 postoperative | 
| Best Corrected Distance Visual Acuity (BCDVA) by Visit | BCDVA (measurement with the participant's best spectacle correction) was assessed at a distance of 6 meters or 20 feet using a standard Snellen eye chart, both monocularly and binocularly, and reported categorically as a percentage of eyes analyzed. | Baseline, Month 1, Month 3 postoperative | 
| Manifest Refraction Spherical Equivalent (MRSE) | The participant was manually refracted to his/her best correction using a phoropter and standard Snellen eye charts. Each eye contributed separately to the analysis. | Baseline, Month 1, Month 3 postoperative | 
| Prediction Error Between Target Versus Achieved Refraction at One and Three Months Post-op | Prediction error was summarized as a percentage of eyes within 0.5 D and 1.0 D of target at one and three months postoperative | Month 1, Month 3 postoperative |