All ETDs from UAB

Advisory Committee Chair

Paul D Gamlin

Advisory Committee Members

Adrienne C Lahti

Tim J Gawne

Lei Liu

Elliot L Hong

Richard J Leigh

Document Type

Dissertation

Date of Award

2012

Degree Name by School

Doctor of Philosophy (PhD) School of Optometry

Abstract

Background: Compared to healthy controls (HC), patients with schizophrenia (SZ) have lower smooth pursuit gain and have been reported as having a higher prevalence of convergence insufficiency. To date, however, there have been no reports on vergence tracking gain in such patients. Therefore, we investigated both static and dynamic vergence behavior in healthy controls and patients with schizophrenia. Methods: Eye movements were recorded in multiple tasks including antisaccades, triangular waveform smooth pursuit at multiple frequencies, and triangular waveform vergence tracking of a real target at multiple frequencies. Eye position data were collected at 500 Hz using a binocular video eye tracker. Results: Consistent with previous reports, the SZ group exhibited lower gains than HC group during smooth pursuit tasks (0.5 Hz gain: HC=0.73, SZ=0.64, p<0.05; 1.0 Hz gain: HC=0.45, SZ=0.35, p<0.05). For vergence tasks, when compared to the HC group, the SZ group did not demonstrate a significantly greater incidence of convergence insufficiency, but did exhibit significantly lower gains during vergence tracking tasks (0.05 Hz: gain: HC=0.90, SZ=0.67, p<0.05; 0.1 Hz gain: HC=0.88, SZ=0.65, p<0.05; 0.25 Hz gain: HC=0.86, SZ=0.59, p<0.01). There was significant correlation between the smooth pursuit and vergence tracking gains in the SZ group. The HC group did not exhibit significant correlations between the smooth pursuit and vergence tracking gains. Conclusions: We did not observe a significantly increased rate of convergence insufficiency in patients with schizophrenia. However, our observations clearly demonstrate previously unreported vergence tracking deficits in such patients.

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