Straylight as an additional indicator in surgical refractive procedures.

Various means for the correction of refractive errors, including surgical
procedures, are available nowadays. In the absence of early cataract, phakic
intraocular lens (PIOL) implant is one of the suited procedures, whereas in the
presence of early cataract, refractive lens exchange (RLE) is suited. The
absence or presence of early cataract is assessed by ophthalmologists using
slitlamp examination and classical parameters of visual function (visual acuity
[VA] and contrast sensitivity [CS]). However, subclinical lens opacities may
not be identified by slitlamp examination. Although these subclinical opacities
may already cause a functional effect, it may not yet affect VA and CS tests.
However, it may already affect the straylight parameter. In the presence of
early cataract there may be a discrepancy between ophthalmologist's assessment
of the degree of cataract and the patient*s subjective complaints (e.g.
functionally insignificant versus significant cataract). The main cause for
such a discrepancy is glare caused by forward light scatter (i.e. straylight).
Improvement of visual function after refractive correction may, in part, be due
to a reduction of straylight after replacement of the lens, together with its
opacities. It is expected that straylight measurement can be used to
distinguish the relative contribution of refractive error and glare to visual
function impairment.

To evaluate whether straylight assessments [log(s)] can contribute to
develop/refine the decision tree for the indications AC-PIOL, RLE or CE.

Prospective observational case series (pre-post design)

Participants do not benefit. Risks are negligible. Patients will be subjected
to study-related measurements twice (i.e. pre- and postoperatively).
Measurements will be performed at the time of regular visits to Focus
Clinic/The Rotterdam Eye Hospital. For the straylight measurements pupils will
be dilated by eyedrops. On average, the extra time required will be 1 hour
every visit.