The effect of a single oral dose of propanolol 80 mg, dilevalol 200 mg, salbutamol 4 mg, and placebo on the systolic (BPs), diastolic blood (BPd), intraocular pressure (IOP), on retinal vessel diameter (D), blood velocity (Vmax) and volumetric retinal blood flow (RBF), was measured at baseline, 90 minutes and three hours after administration in normotensive diabetic volunteers. These drugs were chosen to demonstrate a range of 8 receptor activity. Propanolol is a non-specific ß blocker, affecting ß1 and ß2 receptors, dilevalol has ß1 antagonist and ß2 agonist effects and salbutamol has ß2 agonist effects. Retinal blood flow was measured by bidirectional laser Doppler velocimetry (BLDV) and red free photography.
Dilevalol reduced the mean BPs by 10.4 mmHg (SD 4.2, P<0.05), the mean BPd by 7 mmHg (SD 3.8, P<0.05), whereas propanolol, salbutamol and placebo had no significant effect. Propanolol reduced the mean intraocular pressure by 4.88 mmHg (SD 1.8, P<0.01). No treatment had a significant effect on retinal perfusion pressure. In all treatments the vessel diameter and volumetric flow remained unchanged, and there was no significant difference between the treatments. The mechanisms of action of these drugs are analysed and the possible implications of their use in patients with retinal disease are discussed
LaniganL.P., ClarkC.V., AllawiJ., HillD.W., KeenH.. Responses of the retinal circulation to systemic autonomic stimulation in diabetes mellitus. Eye1989; 3: 39–47
2.
GrunwaldJ.E.. Effect of topical timolol on the retinal circulation. Invest Ophthalmol Vis Sci1986; 27: 1713–9
3.
GrunwaldJ.E.. Effect of timolol maleate on the retinal circulation of human eyes with ocular hypertension. Invest Ophthalmol Vis Sci1990; 31: 521–6
4.
MartinX.D., RabineauP.A.. Vasoconstrictive effect of topical timolol on human retinal arteries. Graefes Arch Clin Exp Ophthalmol1989; 227: 526–30
5.
HyerS.L., KohnerE.M., DaviesG., MackayE.M., VandenB.M.. Effects of two beta-antagonists (dilevalol and propanolol) on retinal flood flow: a double-blind placebo controlled study. J Hypertens Suppl1989; 7: 268–9
6.
HyerS.L., KohnerE.M., DaviesG., MackayE.M., VandenBurgM.J.. Effects of dilevalol, propanolol and placebo on retinal blood flow, blood pressure and heart rate: a double-blind study. J Hum Hypertens1990; 4: 63
7.
KohnerE.M., HamiltonA.M., SaundersS.J., SutcliffeB.A., BulpittC.J.. The retinal blood flow in diabetes. Diabetologia1975; 11: 27–33
8.
KohnerE.M.. Dynamic changes in the microcirculation of diabetics as related to diabetic microangiopathy. Acta Med Scand Suppl1975; 578: 41–7
9.
GrunwaldJ.E., RivaC.E., SinclairS.H., BruckerA.J., PetrigB.L.. Laser Doppler velocimetry study of retinal circulation in diabetes mellitus. Arch Ophthalmol1986; 104: 991–6
10.
FallonT.J., MaxwellD.L., KohnerE.M.. Autoregulation of retinal blood flow in diabetic retinopathy measured by the blue-light entoptic technique. Ophthalmology1987; 94: 1410–5
11.
GrunwaldJ.E., RivaC.E., PetrigB.L., SinclairS.H., BruckerA.J.. Effect of pure 02-breathing on retinal blood flow in normals and patients with background diabetic retinopathy. Curr Eye Res1984; 3: 239–41
12.
GrunwaldJ.E., RivaC.E., MartinD.B., QuintA.R., EpsteinP.A.. Effect of an insulin-induced decrease in blood glucose on the human diabetic retinal circulation. Ophthalmology1987; 94: 1614–20
13.
FallonT.J., ChowiencyzkP., KohnerE.M.. Measurement of retinal blood flow in diabetes by the blue-light entoptic phenomenon. Br J Ophthalmol1986; 70: 43–6
14.
GrunwaldJ.E., RivaC.E., BruckerA.J., SinclairS.H., PetrigB.L.. Altered retinal vascular response to 100% oxygen breathing in diabetes mellitus. Ophthalmology1984; 91: 1447–52
15.
GrunwaldJ.E., RivaC.E., BruckerA.J., SinclairS.H., PetrigB.L.. Effect of panretinal photocoagulation on retinal blood flow in proliferative diabetic retinopathy. Ophthalmology1986; 93: 590–5
16.
GuazziM., FiorentiniC., PoleseA., OlivariM.T., MagriniF.. Antihypertensive action of propranolol in man: lack of evidence for a neural depressive effect. Clin Pharmacol Ther1976; 20: 304–9.
17.
RivaC.E., GrundwaldJ.E., SinclairS.H., O'KeefeK.. Fundus camera based retinal LDV. Applied Optics1981; 20: 117–20.
18.
FekeG.T., RivaC.E.. Laser Doppler measurements of blood velocity in human retinal vessels. J Opt Soc Am1978; 68: 526–31.
19.
RivaC.E., GrunwaldJ.E., SinclairS.H., PetrigB.L.. Blood velocity and volumetric flow rate in human retinal vessels. Invest Ophthalmol Vis Sci1985; 26: 1124–32.
20.
CaldwellG., DaviesE.G., SullivanP.M., MorrisA.H., KohnerE.M.. A laser Doppler velocimetry study of the effect of hypoglycaemia on retinal blood flow in the minipig. Diabetologia1990; 33: 262–5.
21.
DeloriF.C., GragoudasE.S., FranciscoR., PruettR.C.. Monochromatic ophthalmoscopy and fundus photography. The normal fundus. Arch Ophthalmol1977; 95: 861–8.
22.
BrinchmannH.O., EngvoldO.. Microphotometry of the blood column and the light streak on retinal vessels in fundus photographs. Acta Ophthalmol1986; supp 179: 9–19.
23.
NewsonR.S.B., SullivanP.M., RussamM.B., TaqoeR., and KohnerE.M.. Retinal vessel measurement: Comparison of observer and computer driven methods. In Press: Graefes Arch Clin Exp Ophthalmol1991.
24.
HeierH., BrinchmannH.O.. Reliable measurements from fundus photographs in the presence of focusing errors. Invest Ophthalmol and Vis Sci1989; 30: 674–7.
25.
DamonD.N., DulingB.R.. A comparison between mean blood velocities and center-line red cell velocities as meaured with a mechanical image streaking velocimeter. Microvas Res1979; 4: 330.
26.
KleinR., KleinB.E., MossS.E., DavisM.D., DeMetsD.L.. The Wisconsin epidemiologic study of diabetic retinopathy. III. Prevalence and risk of diabetic retinopathy when age at diagnosis is 30 or more years. Arch Ophthalmol1984; 102: 527–32.
27.
ArmitageP., BerryG.. Stastical methods in medical research (2nd ed). Blackwell Scientific Publications, Oxford, UK.1987.
28.
RoystonJ.P.. A simple method for evaluating the Shapiro Francia W’ test of Non-Normality. The Statistician1983; 32: 297–300.
29.
SnedecorG., CochranW.. Stastical methods (8th ed). The Iowa State Univeristy Press, Ames, Iowa, USA1989.
30.
WinerB.. Statistical principles in experimental design (2nd ed). McGraw-Hill, New York, USA1971.
31.
ParvingH.H., LarsenM., HommelE., Lund-AndersenH.. Effect of antihypertensive treatment on blood-retinal barrier permeability to fluorescein in hypertensive Type 1 (insulin dependent) diabetic patients with background retinopathy. Diabetologia1989; 32: 440–4.
