HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Havelius, U. Articles by Hansen, F. Search for Related Content PubMed PubMed Citation Articles by Havelius, U. Articles by Hansen, F.

Ocular Vasodynamic Changes in Light and Darkness in Smokers

¹From the Departments of Ophthalmology and ²Clinical Physiology, Malmö University Hospital, Lund University, Malmö, Sweden.

PURPOSE. To determine whether smokers have a reduced capacity for increased retinal blood flow velocity in darkness.

METHODS. The peak systolic flow velocities (V_S) and end diastolic flow velocities (V_D) were measured by ultrasound (i.e., color Doppler equipment), in light and darkness in the ophthalmic and central retinal arteries in 20 cigarette smokers and 20 matched nonsmokers. The resistive index (RI) was calculated as RI = (V_S – V_D)/V_S.

RESULTS. In the ophthalmic artery in nonsmokers, the V_D was markedly increased in darkness and the RI was correspondingly reduced. After the subject was re-exposed to light, the RI was markedly increased. In smokers the V_S and V_D did not change significantly in the different conditions of light and darkness. In the central retinal artery in nonsmokers, the V_S and V_D were markedly increased in darkness and decreased after re-exposure to light. In smokers, the corresponding changes were much smaller and not significant.

CONCLUSIONS. The normal capacity for increased blood flow velocity in the central retinal artery in darkness was markedly reduced in smokers. This finding may explain the reduced dark vision after recent smoking reported in several studies and probably reflects the combined effects of an increased blood viscosity, the vasoconstrictive action of nicotine, and a reduced capacity of the blood to transport oxygen, as the hemoglobin is partly occupied by carbon monoxide.

This article has been cited by other articles:

				H. Resch, C. Zawinka, G. Weigert, L. Schmetterer, and G. Garhofer Inhaled Carbon Monoxide Increases Retinal and Choroidal Blood Flow in Healthy Humans Invest. Ophthalmol. Vis. Sci., November 1, 2005; 46(11): 4275 - 4280. [Abstract] [Full Text] [PDF]