Metabolic factors in the development of retinopathy of juvenile-onset type I diabetes mellitus.

Thirty-five patients of insulin-dependent diabetes mellitus (IDDM) were investigated for the effect of various metabolic factors on retinopathy. The severity of retinopathy increased with duration and age of onset of IDDM. Degree of glycaemia (fasting blood sugar, FBS) was similar in patients with or without retinopathy. All IDDM patients as a group showed severe carbohydrate intolerance with lower basal and post glucose serum immunoreactive insulin (IRI) levels and serum C-peptide radioimmunoreactivity (CPR) as compared to controls. The insulin secretory response was similar in no retinopathy, mild retinopathy and severe retinopathy groups. Patients with retinopathy had higher incidence of hyperlipidemia but mean serum levels of cholesterol and triglyceride were similar. This study does not suggest a direct relationship between the various metabolic factors studied and retinopathy due to IDDM.

Experimental inhibition of proliferative vitreoretinopathy in retinal detachment using daunorubicin.

Proliferative vitreoretinopathy (PVR) remains the most common cause of failure in retinal detachment surgery. Surgical procedures for its repair entails complex and extensive instrumentation besides technical skill. The success rate varies widely with high incidence of redetachment. Keeping this in view, we evaluated the role of intravitreal daunorubicin as an anti-mitiotic agent in the inhibition of PVR. Our study concluded that 5 micrograms of intravitreal daunorubicin effectively inhibited PVR in the rabbit eye and the dosage was safe and nontoxic. The half-life of the drug was determined to be about 140 minutes, suggesting a prolonged intravitreal concentration sufficient to prevent fibroblast proliferation.

Anti-insulin antibodies and retinopathy in juvenile onset type-1 diabetes.

Juvenile diabetics have severe loss of beta cell function and require replacement therapy with insulin. Insulin antigenicity can produce anti-insulin antibodies resulting in allergic reactions and insulin resistance. The role of insulin-anti-insulin antibody complexes in the development and progress of chronic diabetic complications like microangiopathy is not very clear. In the present study, there was statistically a significant trend of higher insulin antibody binding levels in IDDM patients who developed retinopathy. Though there was a trend of higher insulin antibody in IDDM patients with retinopathy, there was no association between insulin antibody and HLA antigen which some authors have reported.

Visual evoked responses in tuberculous children on ethambutol therapy.

Visual evoked responses (VERs) were recorded in 47 children, aged 3-13 years with tuberculosis, treated with ethambutol (20 mg/kg/day) as a part of the antitubercular regimen. VERs were evoked by monocular whole field stimulation, the stimulus being provided by a black and white checker-board pattern reversed every 560 msec and recorded before the commencement, 2, 4, 6, 9 and 12 months of therapy and between 3 to 6 months after stopping the drug. In the first 6 months of therapy the mean values of latency ranged from 92.8 to 101.3 msec in the 3 to less than 6 years age group and 88.5 to 100.3 msec in children 6-13 years of age. Between 6-12 months of therapy the mean values of latency were between 93.3 to 101.0 msec in the 3 to less than 6 years age group and 96.0 to 101.5 msec in the older group. Between 3-6 months after stopping therapy the means of latency ranged from 92 to 96 msec. The differences were not statistically significant at any point of time. Thus, children do not seem to be at greater risk for developing ethambutol inducted optic damage as compared to adults. Ethambutol in the above stated dose may, therefore, be recommended for inclusion in antitubercular chemotherapy in pediatrics without undue fear of subclinical toxicity.

Iris neovascularization in Sturge-Weber syndrome.

An unusual case of Sturge-Weber syndrome with raised intraocular pressure is presented. The slit lamp examination and anterior segment fluorescein angiography were consistent with iris neovascularization. Cause and effect relationship of iris neovascularization with glaucoma in this syndrome is discussed.

Ultrasonic errors in analysis of vitreous haemorrhage.

Pre-vitrectomy errors in diagnostic A & B mode ultrasound may result in affection of the surgical outcome. We have done a retrospective analysis of fifty patients who were screened by both A & B mode echography and analyzed the data which revealed that real-time kinetic echography is required for accurate interpretation of the vitreoretinal status. Besides, quantitative A scan examination also has fallacies due to the echo beam not striking the sclerochoroid complex at right angles, and a modification of this technique is suggested. Lastly old retinal detachments may not produce echo-patterns diagnostic of retinal detachments resulting in fallacious interpretation. We recommend that combined A mode and real time B-mode and often repeat echography is essential for accuracy in diagnosis.

Optimum radiation technique for retinoblastoma in conserved eyes.

The study evaluated 121 consecutive unoperated cases of retinoblastoma in children. They received radiation as the primary treatment for their ocular disease. The stage grouping was done according to Reese classification. Ninety four children had their disease evaluated by CT scan. All except one had imaged lesions in both eyes. In addition, twenty six had thickened optic nerves and twenty one showed chiasmal infiltration. Radiation field selection was based on clinical and CT imaged disease. A tumor dose of 4500c Gy in 16 to 19 fractions over 18 to 24 days was delivered by cobalt teletherapy. The target volume encompassed ora serrata anteriorly and optic chiasma posteriorly in all cases. Tumor response and patient survival was correlated with the initial stage and radiation factors utilised amongst them. Encouraging results were obtained using three field radiation technique with an open anterior field and a TDF between 75 and 90.

Gyrate atrophy of the choroid and retina.

A rare case of gyrate atrophy of the choroid and retina is reported in two female siblings. The diagnosis was made on clinical, electrophysiological, angiographic and biochemical features. This possibly is the first documentation of hyperornithemic gyrate atrophy (HOGA) from the Indian subcontinent.

Genetic marker in juvenile diabetic retinopathy.

Thirty five patients with insulin dependent diabetes mellitus (IDDM) were investigated for development of retinal microangiopathy by fluorescein angiography. HLA typing (A,B.C antigens) was done as a genetic marker. There was no statistically significant difference in the frequency of HLA antigens between patients without retinopathy (Gr.I) and with retinopathy (Gr.II) Frequency of various HLA antigens did not differ significantly in the mild and severe retinopathy groups or in comparison with controls. HLA B8 was significantly over represented in the patients of IDDM as a single group (GrI + II) when compared with controls (26% vs 8%). HLA profile was not a predictor of either the development or the severity of retinopathy in IDDM.

Retinal toxicity of trace elements.

Acute toxicity of lead, nickel and cobalt on rabbit retina was studied. It was found that all these metals produced similar photoreceptor degenerative changes, but lead produced extensive degenerative changes at ganglion cell layer also. Electroretinographically nickel group showed statistically (by analysis of variance) significant prolongation of 'b' wave implicit time as seen in autosomal dominant retinitis pigmentosa.