Photopic negative response using a handheld mini-ganzfeld stimulator in healthy adults: normative values, intra- and inter-session variability

Author(s)

Berezovsky, Adriana ^[1] ; Karanjia, Rustum ^{[2, 3, 4, 5]} ; Fernandes, Arthur Gustavo ^[1] ; Santos Botelho, Gabriel Izan ^[1] ; Novele Bueno, Tatiane Luana ^[1] ; Ferraz, Nivea Nunes ^[1] ; Sacai, Paula Yuri ^[1] ; Coupland, Stuart Glenn ^{[4, 5]} ; Sadun, Alfredo Arrigo ^{[2, 3]} ; Salomao, Solange Rios ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Dept Oftalmol & Ciencias Visuais, Escola Paulista Med, Sao Paulo, SP - Brazil

^[2] Doheny Eye Inst, 1355 San Pablo St, Los Angeles, CA 90033 - USA

^[3] Univ Calif Los Angeles, David Geffen Sch Med, Dept Ophthalmol, Doheny Eye Ctr, Los Angeles, CA 90095 - USA

^[4] Univ Ottawa, Ottawa Eye Inst, Ottawa, ON - Canada

^[5] Ottawa Hosp, Res Inst, Ottawa, ON - Canada

• Document type: Journal article
• Source: DOCUMENTA OPHTHALMOLOGICA; v. 142, n. 2 JUL 2020.
• Web of Science Citations: 1

Abstract

Purpose To determine normative values, intra- and inter-session variability for a range of parameters derived from the photopic negative response (PhNR) using a handheld mini-Ganzfeld stimulator in healthy normal adults. Methods Light-adapted flash full-field electroretinograms (ERGs) were recorded from healthy individuals with no visual complaints, visual acuity equal to or better than 0.0 logMAR (20/20 Snellen), and negative family history for visual diseases. ERGs were recorded from both eyes using a DTL(R)type fiber electrode after dilation of the pupils with instillation of 1 drop of tropicamide eye drops (1%). The full-field PhNR stimulus conditions were produced by a LED-based ColorBurst (TM) (Diagnosys LLC, Lowell, MA, USA) handheld stimulator. Red flashes of 1, 5 and 7 cd.s/m(2)on a blue background of 10 cd/m(2)were presented. A-wave, b-wave and PhNR amplitude (determined by both baseline to trough-BT and peak to trough-PT) and peak times were analyzed. Normal limits were determined as 5% percentile for amplitudes and 95% percentile for latencies. Intra- and inter-session variability were assessed with Wilcoxon signed-rank test, intraclass correlation coefficient (ICC) and the coefficient of variability (COV). Results Normative limits for PhNR amplitude (mu V) using 1, 5 and 7 cd.s./m2 stimuli were, respectively: 20.81; 18.06 and 19.60 for BT and 69.11; 77.98; 76.51 for PT. Peak times (ms) normative limits for 1, 5 and 7 cd.s/m2 intensities were, respectively, 65.98; 78.20 and 77.96. Overall, intra-session variability assessed by coefficients of variation ranged from 1.35 to 10.28%. Inter-session variability disclosed significant intraclass correlation values for all PhNR parameters only for 1 cd.s/m2 stimuli. Conclusions The normative values provided by this study are clinically helpful in the diagnosis of inner retinal disorders, especially those affecting retinal ganglion cells such as glaucoma and other optic neuropathies. Further studies, including a larger sample with variable age range would extend the validity of the current results. (AU)

• FAPESP's process: 18/05869-9 - Retinal ganglion cell function assessed by the photopic negative response in Leber's hereditary optic neuropathy
• Grantee: Adriana Berezovsky
• Support Opportunities: Regular Research Grants