No abstract

Conclusion-These results demonstrate an increased expression of VEGF in the RPE, and in the outer nuclear layer in maculae with ARM, that could be involved in the pathogenesis of neovascular macular degeneration. Furthermore, enhanced TGF-expression in the RPE cells of maculae with early stages of ARM was shown. (Br J Ophthalmol 1997;81:154-162) Age-related maculopathy (ARM) is a disorder of the macular area of the eye. Many histopathological changes-for example, drusen and basal laminar deposit (BLD) can be seen in early types of ARM.1 2 The late stages of ARM are nowadays called age-related macular degeneration (ARMD) and are subdivided into dry ARMD (geographic atrophy), and wet ARMD (neovascular ARMD).

Renin, prorenin, and immunoreactive renin were present in vitreous and subretinal fluid of eyes from subjects with and without diabetic retinopathy. Renin substrate, albumin, transferrin, and immunoglobin G were also found in these ocular fluids. In many samples renin levels were close to the detection limit of the assay. The levels of renin substrate, albumin, transferrin, and immunoglobulin G varied widely among ocular fluid samples, but in each individual sample the levels were, relative to each other, similar to those in plasma. In contrast, the prorenin level in ocular fluid was up to 100 times higher than expected on the basis of the plasma protein content of ocular fluid. Moreover, there was little difference in prorenin concentrations between samples with low and high plasma protein contents. Prorenin, relative to albumin and other plasma proteins, was higher in vitreous fluid from eyes with proliferative diabetic retinopathy complicated by traction retinal detachment than in eyes of nondiabetic subjects with spontaneous retinal detachment. It appears that prorenin (and possibly renin) in ocular fluid is controlled by an active and specific process, possibly local synthesis within the eye. In view of the vascular actions of angiotensin II, an intraocular renin-angiotensin system may play a role in diabetic retinopathy.

The direct compensation method allows for an accurate (standard deviation below 0.05 log unit) determination of intraocular light scattering between 3.5 and 25 deg of scattering angle and is suitable for untrained subjects. The method was used to study population behaviour and individual variation in 129 volunteers between 20 and 82 yr of age, visual acuity equal to or better than one and no apparent eye pathology. The results indicate straylight to increase with the 4th power of age, doubling at 70. In addition to the age dependence, there was great variation between individuals. Part of this is due to negative correlation with pigmentation.