The aim of this study is to measure the results of refractive surgery with aspherical intra-ocular lenses quickly and reliably.
ID
Source
Brief title
Condition
- Vision disorders
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Main goal of this research is the comparison of the results of aspheric and
spheric IOLs on contrast sensitivity and depth of focus.
Secondary outcome
The variable rMTF (relative modulation transfer) can be calculated from the
results of a contrast sensitivity test. rMTF is an indicator of the aberrations
of the eye and can be defined as the ratio between de contrast sensitivity in
defocus situations and in optimal focus as function of the spatial frequencies.
Because of this, both the contrast sensitivity tests are performed in four
different defocus situations.
Background summary
Refractive surgery is a surgical treatment, which aims for the correction of
refractive errors. Nowadays, there is a strong tendency to perform refractive
surgery in such a way that spherical aberration and other optical abnormalities
after the operation are minimal. In patients with cataract, this can be
achieved by replacing the cataracteus lens by a synthetic aspherical IOL
(intra-ocular lens). An aspherical IOL contains negative spherical aberration
which compensates the positive spherical aberration of the cornea.
Study objective
The aim of this study is to measure the results of refractive surgery with
aspherical intra-ocular lenses quickly and reliably.
Study design
In this study, two combinations of spherical and aspherical IOL*s will be
compared. After surgery of both eyes, a spherical IOL in one eye and an
aspherical IOL in the fellow eye, two contrast sensitivity tests are performed
on each eye to determine visual capacity. By measuring both in optimal
correction and in different defocus situations, information about depth of
focus and the myopic shift is obtained. Spherical aberration, fundus
examination and cornea topography will also be measured.
Intervention
Besides the spherical IOL, there also will be used an aspherical IOL.
Study burden and risks
Serious side effects as a result of or associated with participation in the
research are not expected. The IOL*s are implanted following protocol.
Implantation of two different IOL*s are widely implemented in the clinic, so no
disadvantages are expected.
To accomplish dilatation of the pupil, which is necessary to make fundus
foto*s, tropicamide (0,5%), two drops per eye, is used. Side effects of
tropicamide are: stinging of the eye when the medicine is applied, blurred
vision, headache, sensitivity of the eyes to light. The drops paralyse the iris
and make accomodation for 4-8 hours impossible. During this time, reading can
be difficult and car driving is discouraged. Other possible side effects are
allergic reaction, increased intra-ocular pressure and dry mouth.
Hanzeplein 1
9713 GZ Groningen
Nederland
Hanzeplein 1
9713 GZ Groningen
Nederland
Listed location countries
Age
Inclusion criteria
- In both eyes cataract
Exclusion criteria
- Cylindric correction larger than 1,5 D
- Macula degeneration if the visual acuity from one or both eyes is less than 0,8
- Glaucoma
- Diabetic retinopathy
- Medication that influences the tear function, pupil size or accomodation of the eye
- Pathology that influences the tear production
- Presence of pathology between the two cataract operations
- Younger than 18 years
- Presence of senile dementia (MMSE < 22)
Design
Recruitment
Medical products/devices used
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 | NL13422.042.06 |