Documenting the fixation at an extrafoveal locus with a modified slit lamp in AMD
Markku T Leinonen 1*
and
Lea Hyvarinen 2
1 Department of Ophthalmology, Turku University Hospital, Turku, Finland
2 Faculty of Behavioural Sciences, University of Helsinki, Helsinki, Finland
* To whom correspondence should be addressed. E-mail: leinonen{at}iki.fi.
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Abstract |
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Purpose: To develop a simple and clinically useful technique for observing the fixation at an extrafoveal locus (preferred retinal locus, PRL) at different targets and texts in age-related macular degeneration, AMD.
Methods: A standard Haag-Streit slit lamp was modified by adding several fixation targets in the illumination pathway for direct observation and documentation of fixation during fundus examination. Fixation patterns were analysed with thirty subjects with age-related macular degeneration.
Results: The location and stability of fixation with various stimuli was possible to record in each subject. In 23 subjects there was no difference between the fixations at ‘star’ and ‘wagon-wheel’ stimuli, in seven subjects they were in clearly different retinal locations. Fixation was unstable in three subjects. The PRL for reading words was detectable with all subjects.
Conclusions: The present assessment technique seems to offer a simple, clinically available technique to record fixation patterns to different targets and texts.
Key Words:
low vision, macular degeneration, central scotoma, eccentric viewing
