%0 Journal Article
%T Changes in ocular flow induced by hypo- and hypercapnia relate to static visual acuity in humans
%A Naoyuki Hayashi
%A Tsukasa Ikemura
%A Nami Someya
%J Eye Reports
%D 2011
%I PAGEPress Publications
%R 10.4081/eye.2011.e8
%X We investigated whether the change in ocular blood flow, induced by hypo- and hypercapnia, is related to static visual acuity. Eleven healthy subjects (26¡À5 years) underwent three treatments. A three-treatment three-period crossover design was used. In the hypocapnia treatment (HYPO), the subjects controlled their minute ventilation (VE) to a target of 25 L/min for 6 min. In the hypercapnia treatment (HYPER), the subjects inspired high-fraction CO2 gas (FICO2 = 4%) for 6 min. In the control treatment (CON), VE was not manipulated. We measured choroidal and retinal blood flow by laser speckle flowmetry as ocular blood flow, and static visual acuity using the Landolt C chart. End-tidal partial pressure of CO2 differed significantly among HYPO, HYPER and CON (21¡À1, 48¡À1, and 42¡À1 mmHg, respectively). Retinal blood flow decreased significantly from the baseline in HYPO (-22¡À5%), but increased significantly in HYPER (+3¡À9%) compared to CON. Decimal visual acuity was significantly lower in HYPO than in the CON (0.21¡À0.1 vs. 0.24¡À0.1 P<0.05). These results suggest that changes in ocular blood flow induced by changes in arterial CO2 partial pressure influences visual acuity.
%K ventilation
%K CO2
%K vision
%K ocular circulation.
%U http://www.pagepressjournals.org/index.php/eye/article/view/85