Insulin treatment of elderly type 2 diabetic patients: effects on retinopathy.

Insulin treatment is reportedly associated with the transient progression of retinopathy, possibly with the development of macular oedema in middle-aged Type 2 diabetic patients. The purpose of this study was to investigate the effect of insulin treatment on eye-grounds in elderly (> 65-year-old) Type 2 diabetic patients with secondary failure of oral antidiabetic-drug therapy. Eye examinations were performed in 37 patients randomized to insulin (n = 19) or sulphonylurea (n = 16) treatment and re-investigated after one year. Insulin treatment reduced HbA1c from 9.3% to 7.3% (p < 0.001) after one year. In the sulphonylurea-treated group, HbA1c did not change (9.1 vs. 9.3%). At the start, 65% of the patients had retinopathy, and after one year progression was noted in 7/35 patients (20%; 5 insulin- and 2 sulphonylurea-treated). In the insulin-treated group, the 5 patients with progression had higher initial fasting blood-glucose levels than other patients in the group (15.8 vs 13.1 mmol/L, p < 0.05). Initial HbA1c levels did not differ between the groups (9.8 vs. 9.1%, n.s.), nor the reduction of HbA1c levels during treatment (2.2 vs. 1.3% n.s.). Thus, diabetic retinopathy in this study was common among elderly Type 2 diabetic patients. The progression of retinopathy may in fact be associated with insulin treatment or improvement of metabolic control.

Intraocular infestation by the reindeer warble fly larva: an unusual indication for acute vitrectomy.

A case of ophthalmomyiasis interna posterior (OIP) caused by the larva of the Reindeer warble fly is reported. The larva was initially found intraretinally in the inferior parts of the fundus. From this position it moved into the macula lutea within two days, causing decreased visual acuity. Acute vitrectomy was performed and the larva was removed through a retinotomy. About two months afterwards a small retinal detachment appeared near the ora serrata, where the larva had entered the eye. The retina was reattached with a scleral buckling procedure. The patient regained most of his vision postoperatively. Pars plana vitrectomy is a safe procedure and we consider that in any case of OIP, with a living larva in the eye, acute vitrectomy should be considered, since the larva may damage vital parts of the eye. Furthermore, the site of entrance should be treated with photocoagulation to prevent retinal detachment.

Dietary modulation of retina phospholipids and photoreceptor function with particular reference to phosphatidylinositol.

The effect of dietary partially hydrogenated herring oil (HHO) on the fatty acid composition of the phospholipids of rat retina and on the amplitude of the a-wave of the electroretinogram (ERG) was studied in rats raised for several generations on an essential fatty acid poor diet. The most significant effect of the dietary treatment was a decreased content of arachidonic acid (C20:4 omega 6) and an increased concentration of docosahexaenoic acid (C22:6 omega 2) and 18:1 isomers associated with the phosphatidylinositol (PI). The a-wave of the ERG showed a decreasing amplitude during the experiment and was reduced with about 30% (P less than 0.004) of the initial value in all rats at the end of the experiment. The pronounced change in the arachidonic content in PI and the decreased amplitude of the a-wave of the ERG suggest that arachidonic acid of the PI has an important function in the visual phototransduction process.

Studies on the effect of 4-methylpyrazole on methanol poisoning using the monkey as an animal model: with particular reference to the ocular toxicity.

Young cynomolgus monkeys (Macaca fascicularis) were chosen as a model to investigate the ocular toxicity in animals poisoned with methanol and treated with 4-methylpyrazole (4-MP). The metabolism of methanol in the monkey was investigated after administration of 4-MP. Plasma levels of methanol, formic acid, 4-MP and 4-hydroxy-MP (4-OH-MP) were determined. After intramuscular injection, 4-MP was rapidly absorbed and depressed the elimination rate of methanol as well as the accumulation of formate in the blood. The results show the same great individual variations in monkeys as in humans regarding the susceptibility to methanol poisoning. Administration of a single dose of 5 g/kg induces a serious intoxication in most monkeys, causing death to some of them. Two monkeys receiving a single dose of 6 g/kg of methanol developed a serious initial inebriation and were treated with 4-MP. These monkeys survived and showed no signs of toxicity on ocular examinations which included ophtalmoscopy and electroretinogram (ERG) recordings.

Clinical observations on ten cases of methanol poisoning with particular reference to ocular manifestations.

Clinical observations on 10 cases of methanol poisoning, with particular reference to ocular manifestations, are reported. Four patients stated that they had blurring of vision, one of these also had a temporary loss of the lower parts of the visual fields and another one visual hallucinations. Hyperaemia or oedema of the optic discs were found in 5 patients. Two of the patients died, another was severely ill and suffered from impaired vision for a long period of time afterwards. In none of the surviving patients detectable remaining damage to the retina could be revealed by recording the a- and the b-waves of the electroretinogram. Recording of the visual evoked responses showed that one patient had transient subnormal amplitudes in one eye. However, on follow-up registrations all of the patients had values within normal limits. The results of the investigation show a considerable individual variation in susceptibility to methanol poisoning.

Normal electroretinogram and no toxicity signs after chronic and acute administration of the alcohol dehydrogenase inhibitor 4-methylpyrazole to the cynomolgus monkey (Macaca fascicularis)--a possible new treatment of methanol poisoning.

High doses of 4-methylpyrazole (4-MP) could be administered to monkeys in long- and short-term experiments without yielding any general toxicity or any toxic influence on the retinal photoreceptors, the conduction of impulses through the retina or on the activity in the inner nuclear layer detectable by recording the electroretinogram (ERG). Both series included a low dose (20 mg/kg) and a high dose level (100 mg/kg), the former being a tentative therapeutic dose. In the first series the substance was administered for 6 weeks and the toxicity regarding clinical signs, hematology and blood chemistry, and gross and microscopic pathology evaluated. Furthermore ophthalmoscopy with assessment of the fundus structures and recordings of the ERG were performed. The second series was mainly concerned with revealing of any direct effect of 4-MP on the ERG. Because of the low toxicity of 4-MP and its powerful inhibitory capacity on alcohol dehydrogenase, the substance should prove a potential tool in clinical alcohol research and an effective antidote in clinical situations where inhibition of alcohol dehydrogenase (ADH) is the key to a successful outcome of, for example, methanol and ethylene glycol poisoning.

Atopy and HLA antigens in patients with keratoconus.

Thirty unrelated Caucasian patients with keratoconus and 30 patients with regular astigmatism which served as a control group were typed for histocompatibility (HLA) antigens. Their serum levels of immunoglobulins were determined and past and present history of atopic disease of their own as well as among their relatives were examined. No association between keratoconus and any specific HLA antigen was noted. Neither was any statistically significant increase of atopic disease in the keratoconus population observed. Nor was any correlation between elevated IgE level and keratoconus found. However, a statistically significant increase of atopic disease among the relatives of the keratoconus group was found. In conclusion, no evidence for HLA association with keratoconus disease was found. The results suggest that there may be a association between keratoconus and atopic disease.

Effect on intraocular pressure of retrobular injection of xylocaine with and without adrenaline.

The changes in IOP were registered in two groups, each comprising 30 patients, after a retrobulbar injection of Xylocaine and Xylocaine-adrenaline respectively. No significant difference between the mean values of the initial pressures and the IOP during the following ten min could be proved in either of the groups, but in several individual cases there was a considerable and unpredictable change in IOP following the injection. After ten min this effect was still often present but less pronounced. The change in IOP was significantly greater when adrenaline was used. As a result of these findings the authors have been inclined to cease using adrenaline in retrobulbar anaesthesia for intraocular surgery of short duration.