Z8 OCT-controlled 2D vs 3D LASIK

June 8, 2020 updated by: Zentrumsehstarke Hamburg

Precision of 2D vs 3D Low Energy Femto-LASIK: Intraoperative and Postoperative OCT-based Study

The aim of this study was to test the hypothesis that OCT-guided 110 µm targeted flaps will result in accurate, predictable, and precise thickness flaps, with low complication rates when performed and compared using both 2D and 3D flap geometry applications and how it correlated to visual experience and quality of life responses during the early postoperative period.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

It has been postulated that it is possible with the Ziemer Femtosecond LDV laser system to create reproducible flaps in terms of thickness and predictability. The aim of this study was to test the hypothesis that OCT-guided 110 µm targeted flaps will result in accurate, predictable, and precise thickness flaps, with low complication rates when performed and compared using both 2D and 3D flap geometry applications. Patient-reported outcomes are increasingly incorporated into clinical trials as they provide access to valuable information on the physical experience of the patient during and after the treatment. A questionnaire will therefore also be introduced in this study to evaluate how well self-reported pain, visual experience, and quality of life responses are correlated with flap geometries in both groups during the early postoperative period. The study holds direct medical benefit to the patient in this that they received an immediate improvement in his/her unaided vision. Moreover, the patient's participation contributes to the medical knowledge about the use of femtosecond lasers for refractive surgery, in particular in view of the use of intraoperative OCT visualization tools. The patients will gain access to the newest technology available for refractive surgery namely a low pulse energy high-frequency femtosecond laser.

Study Type

Interventional

Enrollment (Actual)

13

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Germany
      • Hamburg, Germany, 20251
        • Zentrumsehstärke

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

Key inclusion criteria as described by the German Commission for Refractive Surgery (KRC) are:

  • The recommended range of application for the correction of myopia is up to -8.00 D and for the correction of astigmatism up to 5.00 D.
  • The limited for LASIK correction of myopia is up to -10.00 D and correction of astigmatism up to 6.00 D. If myopic astigmatism is to be corrected, the values for myopia and astigmatism must be added together.
  • The recommended range for correction of hyperopia is up to 3.00 D. Up to 4.00 D is the range of limited application for hyperopia.
  • Age ≥18 years with stable eyesight for over 12 months.

Exclusion Criteria:

Key exclusion criteria as described by the German Commission for Refractive Surgery (KRC):

  • preoperative corneal thickness less than 480 μm
  • predicted stromal thickness under the flap after ablation of less than 250 μm
  • chronic progressive corneal disease and forme fruste keratoconus
  • surgery before the age of 18 years
  • symptomatic cataract
  • Glaucoma with a marked loss of visual field
  • Exudative macular degeneration.
  • Concurrent participation in another ophthalmological clinical study

Exclusion criteria irrespective of the KRC criteria:

  • Undergone former eye surgery
  • Contact lens wear within the two weeks prior to commencement of preoperative measurements

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: 2D LASIK
With the 2D method, the flap resection is created in a planar mode (xy-plane), without vertical cut, at the requested depth.
Device: 2D and 3D cutting method using a low energy Femtosecond laser LDV Z8 for LASIK flap cutting
2D and 3D cutting methods were randomly used in same subjects
Experimental: 3D LASIK
With the 3D method, the flap resection is done in a three-dimensional mode, at the requested depth, with the requested diameter and the desired border (side cut) angle
Device: 2D and 3D cutting method using a low energy Femtosecond laser LDV Z8 for LASIK flap cutting
2D and 3D cutting methods were randomly used in same subjects

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Predictability of central flap thickness in OCT-controlled 110 µm LASIK
Time Frame: 1 month postoperatively
Analyze central flap thickness in OCT-controlled 110 µm LASIK and to report on intended versus achieved flap thickness of one group with a 2D flap geometry in one eye and another group with a 3D flap geometry in the contralateral eye. All OCT measurements will be done in micron metres (µm).
1 month postoperatively

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Comparison of intraoperative flap thickness with pre- and postoperative results
Time Frame: 1 week, 1 month
Measurement of corneal thickness pre flap creation (Corneal Pachymetry measurements expressed in µm indicate the thickness of the cornea before flap was created. This measurement will serve as the baseline measurement. Pachymetry measured again after the flap was created and lifted by means of optical and ultrasonic pachymetry(µm) for both groups and to be compare with postoperative AS-OCT measurements also measured in µm.This will indicate how accurate the intraoperative flap thickness compare to the 1 week and 1 month thickness measurements as swelling and inflammatory processes could influence postoperative measurements.
1 week, 1 month
Postoperative planarity
Time Frame: 1 week, 1 month
Assessment of several measurements taken along the corneal cut on superior, nasal, inferior and temporal points in order to compare the uniformity of the cut between 2D vs 3D geometries. Measurments will be done by means of AS-OCT,measured in µm units.Measurements at two different follow up periods will be analyzed and compared in order to rule out the role that inflammation could possibly play.
1 week, 1 month
Intraoperative flap morphology
Time Frame: During surgery
Observations that are defined by different scales in order to report on important features pertaining to 2D and 3D intraoperative flap geometries eg. the presence and extent of opaque bubble layer (OBL), ease of flap lifting and stromal bed quality in both groups . Intraoperative flap morphology assessment to be done as soon as the flap was created in terms of presence of an opaque bubble layer (no OBL, 30-40% of flap surface, >40% of flap surface). Once the flap was lifted to report on ease of flap lifting (easy/sticky/can not lift) and to describe the stromal bed quality (smooth,tissue bridges, rastered, lines).
During surgery
Postoperative flap properties
Time Frame: 1 week, 1 month
Evaluate flap properties by means of slit lamp biomicroscopy examination. The flap's visual appearance seen with the slit lamp to be described and documented as per the suggested scales during 2 specified follow up visits in terms of edge quality and visibility ('yes/no' If yes= extreme fine line, distinct line or irregular edge), border shape (round, irregular) and interface quality (smooth, lines, cobblestones, grids, microstriae) and be compared between flap geometries (2D and 3D flaps).
1 week, 1 month
Visual outcomes
Time Frame: 1 day, 1 week, 1 month
Compare pre- and postoperative visual acuity (UDVA, CDVA) measurements by means of a Snellen Visual Acuity chart and be expressed in decimal that will be converted to logMar units for the purpose of statistical analysis.
1 day, 1 week, 1 month
Patient reported Outcomes: early recovery period
Time Frame: 1 day, 2Day, 1 week follow up
Conduct a non validated Patient Reported Outcome (PRO) questionnaire adopted and based on the 'Brief Pain Inventory' questionnaire [Porela-Tiihonen] to assess patient's early visual perceptions and pain experience related to their own functional status and wellbeing and to compare between the two eyes since each undergone different cutting geometry (2D vs 3D) methods.
1 day, 2Day, 1 week follow up
Complications
Time Frame: Intra- and postoperatively up to 1 month follow up
Report and document any intra- and postoperative complications that may occur during the time of the procedure or at the 1 month follow up visit.
Intra- and postoperatively up to 1 month follow up

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Zentrumsehstarke Hamburg

Investigators

  • Principal Investigator: Stephan Linke, MD, Zentrumsehstarke Hamburg

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 5, 2019

Primary Completion (Actual)

April 23, 2020

Study Completion (Actual)

April 23, 2020

Study Registration Dates

First Submitted

June 3, 2020

First Submitted That Met QC Criteria

June 8, 2020

First Posted (Actual)

June 11, 2020

Study Record Updates

Last Update Posted (Actual)

June 11, 2020

Last Update Submitted That Met QC Criteria

June 8, 2020

Last Verified

June 1, 2020

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CPFEM-0007-DE

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

It is not clear yet to what extend IPD will be implemented. Patient privacy and confidentiality are the most important factors to consider. We consider sharing limited information upon request.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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