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Ganzfeld changes in short wavelength automated perimetry
Author(s) -
Sukumar S.,
Balekuduru S.
Publication year - 2002
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1046/j.1475-1313.2002.00086_27.x
Subject(s) - optometry , swap (finance) , medicine , ophthalmology , economics , finance
Purpose: The change in perception of background illumination known as Ganzfeld changes occurs while performing perimetry test. It occurs under higher background illumination and whilst covering the non‐tested eye with a black patch. We investigated the occurrence of Ganzfeld changes in Short Wavelength Automated Perimetry (SWAP) and assessed the performance while covering the non‐tested eye with a standard black patch and with a translucent occluder. Methods: Twenty‐eight volunteers of age 22 ± 3 years participated in the study. A custom made 16‐point test was used to analyse the sensitivity with a standard black patch and with the translucent occluder. The number and duration of Ganzfeld changes in each condition were detected by subjective responses. The visual comfort of the subjects under each patching condition was assessed using a comfort scale (0–5) and subject's preference. Results: Ganzfeld changes occurred when a standard black patch was used and appears to influence the ability to see the test targets. With a standard black patch 5 Ganzfeld changes were observed per minute and it varied between 2 and 8 s. The duration and occurrence increased towards the end of the test. Using a translucent occluder almost eliminates the occurrence of Ganzfeld changes and improved the sensitivity ( p = 0.001). Of the 28 subjects, 22 preferred translucent occluder to black patch. Conclusion: Use of a translucent spectacle occluder over the non‐tested eye significantly reduces the Ganzfeld changes and improves the performance in SWAP.