Acta ophthalmologica Scandinavica最新文献

Purpose: To investigate whether antibodies against a 100 kDa protein purified by furosemide affinity chromatography from Ehrlich ascites tumour cells could inhibit Na+, K+, Cl- co-transport in the isolated frog retinal pigment epithelium.

Methods: The rate of Na+, K+, Cl- co-transport across the retinal membrane in the isolated frog RPE preparation was measured as the rate of decrease in the intracellular Cl- activity observed after administration of furosemide in the apical bath. The intracellular Cl- activity was measured with double barrelled Cl- sensitive microelectrodes.

Results: Incubation of frog retinal pigment epithelium for 30 min with antibodies reduced the rate of Na+, K+, Cl- co-transport by 43%, while leaving all other measured electrophysiological parameters intact.

Conclusion: The antibodies inhibit Na+,K+,Cl- co-transport in the frog retinal pigment epithelium. This could be due to binding of the antibodies to the co-transporter itself or to a regulatory protein.

Purpose: To examine if different dose regimens of latanoprost cause a difference in daytime intraocular pressure (IOP) in normal eyes and if such changes could be attributed to an increase in aqueous flow.

Methods: In a randomised, open, cross-over study latanoprost 50 microg/ml was instilled in one eye of 18 volunteers. Three dose regimens (one/three drops once daily or one drop twice daily) were evaluated. IOP was measured at the end of each 14-day treatment period. Aqueous flow and endothelial permeability were assessed by fluorophotometry.

Results: All dose regimens reduced IOP significantly (p < 0.001). Once daily applications reduced IOP more than twice daily (p < 0.01). No statistically significant difference in aqueous flow was detected between different treatments. One drop daily increased aqueous flow compared with control eyes (p < 0.05). A similar, but not statistically significant tendency was present with the other regimens. Corneal endothelial permeability was not affected.

Conclusion: Once daily applications of latanoprost reduce IOP more effectively than twice daily in normal subjects. This cannot be explained by an increase in aqueous flow.

Purpose: To evaluate a new test for peripheral colour contrast sensitivity as a tool for early diagnosis of glaucoma.

Patients and methods: Peripheral colour contrast sensitivity was measured by a computer and colour monitor system developed by Arden and co-workers. The monitor displays an annulus subtending 25 degrees at the retina. During the test, 45 degrees of the annulus is removed in one of four quadrants. The patient is asked to identify this quadrant, first at suprathreshold levels and then as the colour contrast between the annulus and the background is varied in order to establish the threshold for identification. The tested colours were varied along the protan, deutan and tritan colour confusion axes, respectively. Thirty-three normal subjects, 22 glaucoma patients and 69 ocular hypertensive patients were examined. The ocular hypertensive patients were divided into a low risk group, a medium risk group and a high risk group.

Results: The colour contrast thresholds for the glaucoma group and the high risk ocular hypertensive group were significantly (p < 0.001) higher for all three colour axes compared with the normal group. There were also significant (p < 0.05-0.001) differences for all axes between the glaucoma group on the one hand and the ocular hypertensive low risk group on the other hand. There were, however, overlaps in colour contrast thresholds between all groups.

Conclusion: Although there is a large and statistically significant difference in average colour contrast thresholds between normals and glaucoma patients, it was difficult to find an appropriate cut-off point to separate the two groups. Further studies must clarify the influence of early stages of common diseases such as cataract, diabetes and age-related maculopathy on colour contrast sensitivity.

Purpose: To study changes in retinal glial cell components in areas of vascular occlusion secondary to diabetic retinopathy.

Material: The retina from ten eyes of six diabetic patients and from five eyes of five normal controls were studied for immunoreactivity to glial fibrillary acid protein and vimentin (glial cells), S-100 protein (perivascular glial cells), carbonic anhydrase isoenzyme II and CD-57 antigen (Müller cells), and CD-68 antigen (microglia).

Results: The study showed increased immunoreactivity to S-100 protein, corresponding to perivascularly located glial cells in the retina from diabetic patients, except for areas of vascular occlusion where this immunoreactivity was absent. Furthermore, the material invading the lumen of former retinal vessels in areas of vascular occlusion showed immunoreactivity to CAH-II and CD-57, suggesting that this material represents ingrowth of retinal Müller cells.

Conclusions: The findings suggest that at least two types of changes in retinal glial cells are involved in the pathophysiology of diabetic retinopathy, i.e. 1) Reactive changes in the perivascular glial cells in the retina, and 2) Müller cell ingrowth into the former lumen of occluded retinal vessels.