Proliferative diabetic retinopathy. Site and size of initial lesions.

Abstract

The pathogenesis of proliferative diabetic retinopathy is unknown. Although there are some established clinical and histological facts, the exact sequence of events is yet to be determined. Diabetic angiopathy is widespread in the body and appears to be a complication ofand related to the duration of the diabetic state. The essential difference between this and proliferative diabetic retinopathy is the absence of microaneurysm formation and neovascularization outside the eye. It thus seems that local ocular factors, either genetic, metabolic, or anatomical, modify the generalized response. The role of the last factor has not yet been investigated, so that it is not known whether the anatomical pattern of the retinal arteries and veins has any relationship to the sites and size of areas of neovascularization.It is the purpose of this paper to study the size and distribution of those areas in early proliferative diabetic retinopathy which are of sufficient size to be visible in fundus photographs and to subject them to statistical analysis to see if any definable pattern emerges. Material103 patients with proliferative diabetic retinopathy are under regular review with regard to their diabetic state and in particular the fundus changes. 170 eyes in these patients were studied. All fundi were photographed in multiple fields using the Zeiss fundus camera at about 3-monthly intervals. The data collected in this survey are taken from these photographic records made at the first or second visits.Of the 170 eyes studied, 86 were suitable for inclusion in the present survey as the new vessels were in an early stage of formation. The remainder were excluded because the areas of proliferation were too diffuse and advanced at the initial visit and the origin of the new vessels was obscured or obliterated by connective tissue. The criteria for inclusion were: (i) There were good photographic records of the fundus at the first or second visit. (2) There was photographic continuity from the area of neovascularization to the optic disc, using one or more photographic fields.(3) The site of origin of an area of neovascularization was discrete, so that the relationship of the feeding vessels to the main retinal vein and the optic disc could be accurately measured. MethodA fixed projector was used to project the photographs a fixed distance onto a solid white wooden screen. All areas of neovascularization visible on the initial photographs were documented, thus giving a record of the lesions as they present to the ophthalmologist. A composite diagram was

Non‐stereo photographic screening in long‐term follow‐up for detection of proliferative diabetic retinopathy

“…The preferred locations of new vessels were the temporal arcades and the area nasal to the optic disc. This confirms earlier findings of predilection of new vessel growth (Taylor & Dobree 1970) or recurrence of such after panretinal phocoagulation (Prskavec 1984). The optic disc centered photograph in the standard procedure is therefore of great importance.…”

Vasodilation of rat retinal microvessels induced by monobutyrin. Dysregulation in diabetes.

“…Interestingly, the increased severity of diabetic retinopathy is correlated with increasing venous abnormalities in humans (25), consistent with monobutyrin's preference for venal dilation (see Results). In addition, monobutyrin is also angiogenic (4) and therefore may play a role in the damaging vasoproliferation that occurs in the advanced stages of diabetic retinopathy.…”

Monoscopic versus Stereoscopic Retinal Photography for Grading Diabetic Retinopathy Severity

“…6 Neovascularization in areas other than the disc is commonly located at arteriovenous crossings. 29 Large nets of neovascularization can cross over retinal vessels, a telltale sign not dependent on stereopsis 1 and is more frequently found on temporal than nasal veins. 29 The superotemporal quadrant is the most frequent initial site.…”

“…29 Large nets of neovascularization can cross over retinal vessels, a telltale sign not dependent on stereopsis 1 and is more frequently found on temporal than nasal veins. 29 The superotemporal quadrant is the most frequent initial site. 30 Most initial neovascularization is within 6 disc diameters of the optic disc.…”