Pattern noise (PANO): a new automated functional glaucoma test
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.
KeywordsGlaucoma Visual field Healthcare research
Compliance with ethical standards
Conflict of interest
No conflicting relationship exists for any author.
- 1.World Health Organization (2007) Global initiative for the elimination of avoidable blindness: action plan 2006–2011. http://www.who.int/iris/handle/10665/43754
- 9.Johnson CA, Thapa SS, Robin AL (2014) PO412. Use of an iPad tablet to perform visual field screening in Nepal. Paper presented at the American Academy of Ophthalmology (AAO) annual meeting, McCormick Place, Chicago, USAGoogle Scholar
- 12.Committee for Development Policy (2015) The least developed country category. 2015 country snapshot. https://www.un.org/development/desa/dpad/wp-content/uploads/sites/45/LDC_Fact_Sheet_booklet.pdf
- 16.Kloevekorn S (2014) Test acer aspire E1-572G-54204G50Mnkk notebook. http://www.notebookcheck.net/Review-Acer-Aspire-E1-572G-54204G75Mnkk-Notebook.99958.0.html
- 25.Drum B, Massof R, O’Leary D, Quigley H, Breton M, Krupin T, Leight J, Mangat-Rai J (1987) Pattern discrimination perimetry: a new concept in visual field testing. In: Greve EL, Heijl A (eds) Seventh international visual field symposium, Amsterdam, September 1986. Springer, Dordrecht, pp 433–440. doi: 10.1007/978-94-009-3325-5_55 CrossRefGoogle Scholar
- 30.De Tarso Ponte Pierre-Filho P, Schimiti RB, De Vasconcellos JPC, Costa VP (2006) Sensitivity and specificity of frequency-doubling technology, tendency-oriented perimetry, SITA Standard and SITA fast perimetry in perimetrically inexperienced individuals. Acta Ophthalmol Scand 84(3):345–350CrossRefGoogle Scholar