Impaired retinal autoregulation in small retinal arterioles before and after focal laser treatment for diabetic maculopathy.
OBJECTIVE
To study the effect of an acute increase in the arterial blood pressure on the diameter response of retinal arterioles supplying areas with focal diabetic macular oedema before and after laser photocoagulation, and control arterioles supplying areas without oedema.


METHODS
In 17 diabetic patients the diameter response of arterioles after an increase in the arterial blood pressure induced by isometric exercise was studied using the retinal vessel analyser (RVA). In each patient a study arteriole supplying a focal area of macular oedema as well as a control arteriole supplying a retinal area without retinopathy lesions was selected, and the diameter response of these vessels was performed immediately before, and 1 hour and 3 months after focal laser photocoagulation of the focal oedema area.


RESULTS
The diameter response was impaired in both study arterioles and control arterioles before focal laser photocoagulation. The treatment induced regression of the focal retinal oedema, but did not affect the diameter response in the arteriole supplying this area (p = 0.85).


CONCLUSIONS
Impairment of the diameter response in small arterioles from diabetic patients does not parallel the regional distribution of retinopathy lesions. Other factors than disturbed autoregulation are probably involved in generating flow disturbances and oedema in diabetic maculopathy.
Jeppesen
P
P
Department of Ophthalmology, Arhus University Hospital, Denmark. pj@dadlnet.dk
Bek
T
T
D000328:Adult; D001160:Arterioles / Q000473:pathology / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology; D003930:Diabetic Retinopathy / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D017075:Laser Coagulation / Q000379:methods*; D008269:Macular Edema / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012171:Retinal Vessels / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology