Retinal function in relation to improved glycaemic control in type 1 diabetes.

AIMS/HYPOTHESIS: To study long-term changes in retinal function in response to sustained glycaemia reduction in participants with type 1 diabetes. METHODS: Prospective study using objective measures of retinal function in 17 participants with type 1 diabetes mellitus and minimal to moderate retinopathy who switched from conventional subcutaneous injection to continuous subcutaneous infusion of insulin (CSII). RESULTS: Glycated haemoglobin HbA(1c) gradually decreased from 9.1% at baseline before CSII to 7.4% after 1 year on CSII. Glycaemia was markedly reduced within 1 week after initiation of CSII and remained stable thereafter. Dark adaptation and retinal electroretinographic function at 1, 4 and 16 weeks after initiation of CSII were comparable with baseline values, whereas a significant improvement in rod photoreceptor dark adaptation and dark-adapted b-wave amplitudes were seen after 52 weeks (time to rod-cone break -25% [p < 0.0001], time to a standardised rod intercept -13% [p < 0.0001], dark-adapted rod b-wave full-field amplitude +15% [p = 0.0125], standard combined rod-cone b-wave amplitude +8% [p = 0.049]). No detectable change was observed in cone adaptation, electroretinographic cone function or retinopathy. CONCLUSIONS/INTERPRETATION: After initiation of CSII, the retinal visual pathway of the rods improved with a delay of more than 4 months, over a time scale comparable with the duration of the diabetic retinopathy early worsening response to sustained glycaemia reduction. This indicates that glycaemia has a long-term effect on the disposition of functional capacity in the retinal visual pathway of rod photoreceptors, the cells that appear to be driving the development of diabetic retinopathy.

CNS metastasis from malignant uveal melanoma: a clinical and histopathological characterisation.

AIM: To characterise uveal melanoma that has metastasised to the central nervous system (CNS). METHODS: Review of 2365 patients constituting all patients diagnosed as having primary uveal melanoma in Denmark during the period 1943-1997. All patients with malignant uveal melanoma and metastasis to the CNS were identified. For each patient, clinical and histopathological data were gathered. RESULTS: Sixteen patients with CNS metastasis were identified. The median age was 58 years. The majority of CNS metastases were located in the frontal and parietal lobes. Eleven patients had widespread metastases. Five patients had exclusively metastasis to the CNS. The average time from diagnosis of primary tumour to symptoms of CNS metastasis was 91 months. The average time from the initial CNS symptoms to death was 20 months. All tumours were composed of either mixed or spindle cells. The average largest basal diameter of the primary tumours was 12 mm. One tumour was a ring melanoma. The majority of tumours had a ruptured Bruch membrane. Retinal invasion was observed in 36% of tumours. No specimen had optic nerve invasion. Scleral invasion was pronounced in 36% of cases, and extrascleral extension was observed in two cases (14%). The amount of tumour infiltrating lymphocytes was pronounced in three cases (23%). CONCLUSION: The proportion of uveal melanoma patients having CNS metastasis was 0.7%. Eleven patients had multiple organ metastases, and the average time from the initial CNS symptoms to death was 8 months. Five patients had metastasis to the CNS solely, and the average time from the initial CNS symptoms to death was 57 months.