The objective of this study is to make a comparison between six different cornea topography measurement systems.
ID
Source
Brief title
Condition
- Vision disorders
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The primary parameters are the coefficients of the main Zernike-polynomials for
coma-like aberrations C(3/-1) and C(3/1). These represent the objective results
of the different cornea topography measurement instruments.
Secondary outcome
Besides comparing the objective results of the instruments, it is also
important to study the clinical user friendliness of the instruments. Therefore
the time of total measurement of each instrument with each patient will be
measured. Furthermore will the operator and the subject judge each instrument
using grades from 1 to 10, where 1 is worst and 10 is best, on comfort and
patient friendliness.
Background summary
Cataract extraction is one of the most commonly performed ophthalmologic
surgeries, where the crystalline natural lens is replaced by an intraocular
lens (IOL). The design of the IOL is nowadays focused on personalizing the lens
to the aberrations (optical imperfections) of the individual eye of the patient
for an optimal sight.
The aberrations in the human eye are majorly caused by the cornea and the lens.
With cataract surgery the lens is removed and thus the aberrations of the
cornea remain. To enhance the optical performance of the pseudo-phakic eye (eye
after cataract extraction) it should be aimed for to compensate all aberrations
of the cornea with the IOL, leaving a perfect sight. The first step in such a
novel approach is a reliable and reproducible measurement of the aberrations of
the cornea.
The determination of the aberrations in the cornea is performed by looking at
the topography of the cornea. There are several instruments which are
potentially capable of measuring and imaging the topography of the cornea and
therefore it is important to investigate the differences of these systems. The
instruments in this study will be judged on both the quality of the results and
user and patient friendliness.
Study objective
The objective of this study is to make a comparison between six different
cornea topography measurement systems.
Study design
The cornea of both eyes of all the subjects will be measured with six cornea
topography imaging systems. These instruments are located at the University
Medical Centre Groningen. The order of the instruments and left/right eye will
be randomized. The randomized order in which the instruments are used is
generated beforehand. The instruments are spread over two locations with three
instruments each. These locations are pretty far from each other, thus it would
be very inefficient to walk back and forth between these locations. Therefore
it is chosen to first randomize the order of the locations that is used and
then generate a randomized sequence of the instruments located at each
location. The order in which the eyes are measured with each instrument is
fixed: the right eye is fixed in all subjects.
Furthermore the subjects are asked to grade the comfort and patient
friendliness of each instruent with a grade from 1 to 10, where 1 is worst and
10 is best. All in all it is expected that the whole procedure will not take
more than one hour.
The six instrument consist of five commercial instruments and one instrument
which was designed for research purposes: the Dubbelman Scheimpflug. This last
instrument will serve as a golden standard, since it is not a black box like
the commercial ones.
The following cornea topography measuring systems are included in this study:
1. Orbscan
2. IOL-master
3. combined Topcon refracto/keratometer
4. Dubbelman Scheimpflug
5. Galilei (Zeimer)
6. Pentacam (Oculus)
Study burden and risks
It is thought that there is no risk for the subjects and the burden is minimal.
The instruments that are tested use optical techniques and thus the eye will
not be touched. Furthermore are five of the instruments commercial available
and thus fully tested and licensed for use in the medical setting. Even the
Dubbelman Scheimpflug, which is not commercial available, is an adjusted
commercial instrument originaly. Non of these adjustments are made on the
measurement unit of the instrument however and thus the subject will not run
any risk.
Participation in this study requires the subjects to come to the University
Medical Centre Groningen for measurements of about one hour.
W.A. Scholtenstraat 12-14
9712KW Groningen
Nederland
W.A. Scholtenstraat 12-14
9712KW Groningen
Nederland
Listed location countries
Age
Inclusion criteria
Subjects without any history of corneal eye diseases are included in this study.
Exclusion criteria
Subjects that have worn contact lenses for the past two years are excluded from this study. Furthermore subjects that had refractive surgery in the past are also excluded.
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL31712.042.10 |