Documenting Fixation at an Extrafoveal Locus with a Modified Slit Lamp in Age-Related Macular Degeneration

PURPOSE. To develop a simple and clinically useful technique for observing fixation at an extrafoveal locus (preferred retinal locus [PRL]) with different targets and texts in age-related macular degeneration (AMD). METHODS. A standard 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 analyzed in 30 subjects with AMD. 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 in all subjects. CONCLUSIONS. The present assessment technique seems to offer a simple, clinically available technique to record fixation patterns to different targets and texts.