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Measurement Repeatability in Contemporary Aberrometry

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ClinicalTrials.gov Identifier: NCT02687022
Recruitment Status : Unknown
Verified February 2016 by Bruce Allan, Moorfields Eye Hospital NHS Foundation Trust.
Recruitment status was:  Not yet recruiting
First Posted : February 22, 2016
Last Update Posted : February 22, 2016
Sponsor:
Information provided by (Responsible Party):
Bruce Allan, Moorfields Eye Hospital NHS Foundation Trust

Brief Summary:
Wavefront scans are a common form of diagnostic test applied in preparing patients for laser eye surgery. An optical map of the eye is created by wavefront scanning, and information from these maps is used to program lasers used to correct focusing errors in the eye. Here the investigators are comparing how repeatable measurements are with a new wavefront scanner and one that is already in widespread use.

Condition or disease Intervention/treatment Phase
Refractive Errors Device: Peramis aberrometry Device: iDesign aberrometry Not Applicable

Detailed Description:

Aberrometers are used to measure each element of defocus (aberration) in an optical system. In LASIK, information derived from aberrometry (scans performed using aberrometers) is used to program the pattern of laser pulses delivered by an excimer laser in therapeutic reshaping of the cornea to correct defocus. To do this accurately, aberrometry findings need to be repeatable and correspond closely to manifest refraction. Here the investigators compare repeatability of measurements for a new aberrometer (Peramis) versus the aberrometer most widely used in contemporary wavefront guided laser vision correction (iDesign).

The test aberrometer will be:

Peramis (Schwind Eye-tech Solutions, Kleinostheim, Germany).

Control aberrometer will be:

iDesign (AMO, Santa Clara, CA)


Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 60 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Investigator)
Primary Purpose: Diagnostic
Official Title: A Comparative Study of Measurement Repeatability for Two Aberrometers
Study Start Date : March 2016
Estimated Primary Completion Date : June 2016
Estimated Study Completion Date : September 2016

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: Myopia (Peramis)
Peramis aberrometry: 30 consecutive LASIK candidates with myopia and regular astigmatism who agree to participate in the study will have up to 4 aberrometry scans acquired consecutively using the Peramis (test) aberrometer.
Device: Peramis aberrometry
A non-invasive photographic scan sequence acquired in under 10 seconds
Other Name: Wavefront scanning

Active Comparator: Myopia (iDesign)
iDesign aberrometry: The same 30 consecutive LASIK candidates scanned in the Myopia (Peramis) arm will also have up to 4 aberrometry scans acquired consecutively using the iDesign aberrometer (control) aberrometer. The order of scans (Peramis and iDesign) will be randomised.
Device: iDesign aberrometry
A non-invasive photographic scan sequence acquired in under 10 seconds
Other Name: Wavefront scanning

Experimental: Irregular astigmatism (Peramis)
Peramis aberrometry: 30 consecutive cases with stage II-III keratoconus or post corneal transplantation cases with irregular astigmatism will have up to 4 aberrometry scans acquired consecutively using the Peramis (test) aberrometer
Device: Peramis aberrometry
A non-invasive photographic scan sequence acquired in under 10 seconds
Other Name: Wavefront scanning

Active Comparator: Irregular astigmatism (iDesign)
iDesign aberrometry: 30 consecutive cases with stage II-III keratoconus or post corneal transplantation cases with irregular astigmatism will also have up to 4 aberrometry scans acquired consecutively using the iDesign aberrometer (control) aberrometer. The order of scans (Peramis and iDesign) will be randomised.
Device: iDesign aberrometry
A non-invasive photographic scan sequence acquired in under 10 seconds
Other Name: Wavefront scanning




Primary Outcome Measures :
  1. 2nd to 4th order aberrations (5mm pupil). [ Time Frame: <10 seconds ]
    M, J0, J45, Coma, Trefoil, Spherical Aberration. Different types of defocus or aberration can be defined and measured by wavefront scanning. Aberrations are classified and quantified by a mathematical treatment called Zernike analysis in which harmonic elements of the waveform of the light detected by the wavefront sensor (aberrometer) are quantified in sequence, starting with simple (lower order) waveforms such as sphere and cylinder (M, J0, J45) corrected in a normal spectacle prescription, and progressing through more complex (higher order) waveforms including, coma, trefoil and spherical aberration which may influence quality of vision. The amount of each aberration varies as a function of pupil size. So pupil size is standardised at 5mm diameter for quantification.


Secondary Outcome Measures :
  1. % of patients with qualifying scan sequence [ Time Frame: <5 minutes ]
    % of patients in whom two 5mm diameter aberrometry scans can be acquired within 4 attempts



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Ages Eligible for Study:   21 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Myopic LASIK candidates (manifest refraction spherical equivalent range 0 to -10 diopters with up to 6 diopters cylinder) or patients attending corneal service with stage II-III keratoconus or post-keratoplasty

Exclusion Criteria:

  • Visually significant co-pathology (CDVA<6/6) other than irregular astigmatism;
  • Patients unable to complete a sequence of 2 good scans (acquisition diameter >5mm) in one eye within 4 attempts

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02687022


Contacts
Contact: Angelique Thomas 02075662156 angelique.thomas@moorfields.nhs.uk
Contact: Barbara Stacey 02075662320 barbara.stacey@moorfields.nhs.uk

Sponsors and Collaborators
Moorfields Eye Hospital NHS Foundation Trust
Investigators
Principal Investigator: Bruce Allan, MD FRCOphth Moorfields Eye Hospital NHS Foundation Trust

Publications:
Responsible Party: Bruce Allan, Consultant Ophthalmic Surgeon, Moorfields Eye Hospital NHS Foundation Trust
ClinicalTrials.gov Identifier: NCT02687022     History of Changes
Other Study ID Numbers: ALLB1019
First Posted: February 22, 2016    Key Record Dates
Last Update Posted: February 22, 2016
Last Verified: February 2016
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Plan Description: The investigators plan to publish summary descriptive data and analyses. Anonymised individual data will be available to systematic reviewers on request.

Additional relevant MeSH terms:
Refractive Errors
Eye Diseases