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Jayter Silva Paula, Fuad Moraes Ibrahim, Denny Marcos Garcia, Antonio A. V. Cruz, Maria de Lourdes Veronese Rodrigues; Non-glaucomatous blindness is associated with changes in spontaneous blinking activity. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):522.
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© ARVO (1962-2015); The Authors (2016-present)
The effect of chronic light deprivation induced by non-cortical blindness on the spontaneous blinking (SB) activity has not been investigated. The aim of this study was to measure the SB metrics in a group of glaucomatous and non-glaucomatous blind subjects.
Magnetic search coil technique was used to register the SB activity of 18 normal controls, aged (mean±SD) 59.1±7.6 years-old; 11 blind patients due to primary open angle glaucoma (POAG), aged 67.6±9.9 years-old; and 10 blind patients due to non-glaucomatous causes such as retinal disorders and cataract, aged 62.7±10.9 years-old. Blindness was defined as the best-corrected visual acuity of less than 20/400 in the better eye. All subjects did not present with any neurological or eyelid diseases that could affect SB. In order to avoid any confounding ocular surface effects, data were collected after topical anesthesia with proxymetacaine 0.5%. SB was recorded during five minutes of an audio listening. One-way analysis of variance was used to compare SB amplitude, peak velocity, duration, main sequence, interblink interval (IBI) and blink rate (BR) between groups.
Non-glaucomatous blind patients presented significantly lower amplitude (mean±SE: 21.4±2.4o vs 29.2±1.8o; p=0.036) and BR (mean±SE: 8.5±3.8 blinks/min vs 21.3±2.8 blinks/min; p=0.027), as well as larger IEI (mean±SE: 9.7±1.5 s vs 4.6±1.2 s; p=0.038) than controls. Blind POAG patients did not differ from controls in all variables studied. No difference between groups was observed regarding peak velocity, duration and main sequence values.
Amplitude, BR and IBI are reduced in non-glaucomatous blind patients. These results suggest the effect of blindness on SB activity is not uniform, and may not be related to glaucoma.
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