The effect of calcium dobesilate on capillary resistance and background retinopathy was compared with placebo in a double-blind cross-over trial on 18 diabetics. Each treatment lasted 8 months. The trial produced no evidence in favour of a significant beneficial effect of calcium dobesilate on the capillary resistance in diabetics or on the course of the diabetic retinopathy.

The fall in applanation pressure after intravenous acetazolamide was followed in seven patients with normal intraocular pressures and in five patients with monolateral glaucoma. The experimental pressure decay curves were compared with similar curves calculated on the basis of different values for the facility of outflow of aqueous humour, and on the assumption of a prompt shift in the rate of aqueous secretion from the preinjectional level to a stable acetazolamide dominated level. The experimental decay curves resembled the matching, calculated curves. The outflow facilities read from the latter averaged 0.4 (range 0.2-1.0) in the normal eyes, and 0.1 (range 0.05-0.15) in the glaucomatous eyes. These results strongly indicate that the above-mentioned assumptions are justified, and that the method allows a simultaneous estimation of outflow facilities in the right and left eye at pressures below the usual. W e find that a study of the shape of the decay curves in glaucomatous eyes might give a clue to the problem of whether the hindrance to the drainage of aqueous humour in the diseased Schlemm system shows reversibility under the decompressing effect of the falling intraocular pressure.