Clinical trial NCT02687022: Measurement Repeatability in Contemporary Aberrometry
Official title: A Comparative Study of Measurement Repeatability for Two Aberrometers
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Refractive Errors
Lead sponsor: Moorfields Eye Hospital NHS Foundation Trust
Sponsor class: OTHER
First posted: 2016-02-22
Enrollment: 60
Sex: ALL
Minimum age (years): 21
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: DIAGNOSTIC

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.

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)

Eligibility 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

Primary outcomes:
measure: 2nd to 4th order aberrations (5mm pupil).
timeFrame: <10 seconds
Secondary outcomes:
measure: % of patients with qualifying scan sequence
timeFrame: <5 minutes
Other outcomes:
Locations:
Study officials:
affiliation: Moorfields Eye Hospital NHS Foundation Trust
name: Bruce Allan, MD FRCOphth
role: PRINCIPAL_INVESTIGATOR
References:
citation: Visser N, Berendschot TT, Verbakel F, Tan AN, de Brabander J, Nuijts RM. Evaluation of the comparability and repeatability of four wavefront aberrometers. Invest Ophthalmol Vis Sci. 2011 Mar 10;52(3):1302-11. doi: 10.1167/iovs.10-5841.
citation: LeDue J, Jolissaint L, Veran JP, Bradley C. Calibration and testing with real turbulence of a pyramid sensor employing static modulation. Opt Express. 2009 Apr 27;17(9):7186-95. doi: 10.1364/oe.17.007186.
citation: Cagigal MP, Valle PJ. Wavefront sensing using diffractive elements. Opt Lett. 2012 Sep 15;37(18):3813-5. doi: 10.1364/ol.37.003813.
citation: Jung JW, Chung BH, Han SH, Kim EK, Seo KY, Kim TI. Comparison of Measurements and Clinical Outcomes After Wavefront-Guided LASEK Between iDesign and WaveScan. J Refract Surg. 2015 Jun;31(6):398-405. doi: 10.3928/1081597X-20150521-06.