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Vera Mönter, David Crabb, Paul Artes; Reclaiming the Periphery - Frequency of Seeing for Static Automatic Perimetry on Peripheral Isopters for Patients with Glaucoma and Healthy Controls. Invest. Ophthalmol. Vis. Sci. 2013;54(15):3916.
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Clinical visual field (VF) tests often focus on the central 30°; an area that neglects more than 80% of a person’s overall VF. However, vision in the far periphery is important for mobility, balance and guidance of attention. Our goal is to establish an automatic kinetic test for the peripheral VF (PVF), complementing standard automated perimetry of the central 30°. We test the hypothesis that there is a consistent relation between responses to static and kinetic stimuli in glaucoma patients and healthy controls allowing us to link both approaches.
PVFs of 15 patients (Mean age: 60 years, MD: -7.2 dB) with glaucoma and 15 controls (Mean age: 39 years) were examined with a fully automated kinetic test on the Octopus 900 (HAAG-STREIT). Stimuli with intensity of 15 dB (III1e) were presented moving at 5°/sec along 16 meridians (Fig1). The median response of three presentations was chosen to define the isopter. As a global measure for PVF defects we defined the mean isopter radius deviation (MIR dev) - the difference of the MIR and the MIR of the age matched normative isopter (Vonthein et al., 2007). For a subgroup of 7 patients and 11 controls frequency of seeing (FOS) curves to size III static stimuli (200ms) were measured at five locations on the isopter (Fig1). Psychometric functions were fitted to determine the sensitivity (50% seeing).
The FOS showed a lower sensitivity for static [median (m): 11.8 dB, 95% CI: 11.3, 12.2] than expected from the kinetic stimuli (15 dB). The difference in sensitivity was similar for controls [m: 12.1 dB, 95% CI: 11.4, 12.7] and glaucoma patients [m:11.3 dB, 95% CI 10.8, 11.9] (Fig2) and was independent of location, age and eccentricity. MIR dev and MD of the central VF were not closely related [r2 = 0.35].
FOS data reveals a consistent difference between static and kinetic sensitivity in glaucoma patients and controls at isopter locations. Despite the different measurement acquisition, both approaches can therefore be combined to measure the peripheral and central VF. A difference in the extent of VF loss in central and peripheral areas may explain the low association between MIR dev and MD in glaucoma patients.
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