International Ophthalmology

, Volume 38, Issue 5, pp 1993–2003 | Cite as

Pattern noise (PANO): a new automated functional glaucoma test

  • Sylvain el-KhouryEmail author
  • Thomas Hannen
  • Diana Carmen Dragnea
  • Faustin Ngounou
  • Paul-Rolf Preußner
Original Paper



To present a newly developed visual field device (pattern noise: PANO) designed to be sensitive to glaucoma defects, cost-effective, material-practical and easy to repair and therefore particularly suited for low-income countries, where glaucoma can be highly prevalent (e.g. sub-Saharan Africa).


This is primarily a descriptive paper, but it also includes a prospective matched case–control pilot study. Hardware, stimulus, target configuration, testing strategy and result sheet are described. The main outcome measure is the contrast level (range 2–64). Targets are composed of bright/dark pixels flickering with 18 Hz and have a size of 5°. Pixel size is approximated to the hill of vision. Average luminance of targets is constant and equals background luminance.The study was performed in the West Region in Cameroon. Twenty eyes of 20 newly presenting patients with glaucomatous optic disc cupping on funduscopy were compared with 20 eyes of 20 normal patients matched in age and laterality of eye.


Mean age was 32.9 ± 18.8 years for glaucoma patients and 32.2 ± 15.6 years for healthy subjects. Mean contrast threshold was significantly higher in eyes with abnormal disc (16.2 ± 14.3 vs. 4.4 ± 0.8, P = 0.002). Correlation of mean contrast thresholds and cup-to-disc ratio was significant (r = 0.59; P = 0.006). Average examination time was significantly longer for glaucoma eyes compared to healthy eyes (8.2 vs. 6.1 min, P < 0.001), whereas error rate did not differ (4.8 ± 2.5% vs. 4.1 ± 1.8%, P = 0.33).


PANO demonstrated visual field defects in patients with glaucomatous optic disc. Defects correlated significantly with glaucomatous optic nerve head morphological alterations. Healthy eyes obtained normal results. More studies are needed to establish PANO.


Glaucoma Visual field Healthcare research 


Compliance with ethical standards

Conflict of interest

No conflicting relationship exists for any author.


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Copyright information

© Springer Science+Business Media B.V. 2017

Authors and Affiliations

  • Sylvain el-Khoury
    • 1
    Email author
  • Thomas Hannen
    • 1
  • Diana Carmen Dragnea
    • 1
  • Faustin Ngounou
    • 2
  • Paul-Rolf Preußner
    • 1
  1. 1.Department of OphthalmologyUniversity Medical Centre MainzMainzGermany
  2. 2.Presbyterian Eye HospitalBafoussamCameroon

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