Influence of multifocal intraocular lens on glaucoma diagnostic tests

Ever since 2006, multifocal intraocular lenses (MFIOL) are being implanted
after cataract extraction to free patients from reading spectacles by applying
the principle of simultaneous vision. However, the design needed to provide
such optical luxury causes at the same time a reduction in the contrast
sensitivity of the eye. Reduction in contrast sensitivity is normally seen in
aging eyes and is also a typical sign of glaucoma eye disease.

Glaucoma is a chronic-progressive disease inducing visual field defects and, if
left untreated, may lead to blindness. The peripheral visual field gets
affected in the early stage of glaucoma, worsening slowly while staying
unnoticed for patients. Only after large parts of the visual field are affected
it becomes symptomatic. Therefore diagnosing and monitoring glaucoma needs to
be accurate and reliable to identify visual field defects or detect
progression. Currently, standard automated perimetry (SAP) is the gold standard
for this in routine clinical practice. SAP measures the retinal contrast
sensitivity of the eye within the visual fields of patients.

A previous study proved however that (SAP) test results are negatively affected
by the optical design of MFIOLs and may therefore, hinder early detection and
optimal glaucoma care. Therefore, we would like to evaluate whether other
relative glaucoma tests are eventually less affected by the optics of the MFIOL
and at the same time reliable enough to ensure, when necessary, optimal
glaucoma care within the group of patients implanted with MFIOLs. Frequency
doubling perimetry (FDT), optical coherence tomography (OCT), and the laser
polarimetry (GDx) are the three tests mainly used in our clinic besides the SAP
to detect visual field defects and assess function and anatomy of the optic
nerve head and are therefore the tests we intend to evaluate.

To determine the influence of MFIOL on glaucoma diagnostic tests namely, the
FDT, OCT, and GDx.

This study has a case series design. MFIOL cases will be compared to the
normative data of the included tests.

A single visit in which FDT, OCT, and GDx are performed, a questionnaire is
completed and a few additional tests to verify the healthy state of the eye.
Total time investment 1 hour. It is possible that an eye disease will be
discovered during the course of this study. The resulting psychological
distress for the subject can be a disadvantage. However, the advantage can be
an earlier adequate treatment. All the measurements are performed with optical
techniques which do not touch the eye and are therefore completely harmless and
thus there is no risk during the experiments.