Non Proliferative Retinopathy Venous Beading

Figure 13.1 Background retinopathy with a few microaneurysms only. This stage is not likely to threaten vision in the near future but tight control of vascular risk factors is important to reduce progression (photograph courtsey of Dr Sailesh Sankar, consultant Physician, University Hospital, Coventry).

Figure 13.3 The same eye as in Fig 13.2, showing relative sparing of the macular region, but the retina is generally ischaemic and at risk of progression to sight threatening neovascularisation (photograph courtsey of Dr Sailesh Sankar, Consultant Physician, University Hospital, Coventry).

basement membrane. They are noticeably larger and often irregular in outline.

Background changes do not cause visual loss but do signify significant vascular disease and, particularly when occurring close to the visual axis, may require more frequent screening examinations.

Pre-proliferative retinopathy Cotton wool spots

Localised ischaemia due to closure of diseased blood vessels results in a 'cotton wool' appearance (Figures 13.2 and 13.3), previously referred to as 'soft exudates', which is a misnomer as the process does not actually involve leakage or exudation. Such changes do not m $

Figure 13.2 Pre-proliferative retinopathy with several cotton wool spots as well as background microaneurysms and blot haemorrhages (photograph courtsey of Dr Sailesh Sankar, Consultant Physician, University Hospital, Coventry).

usually affect acuity themselves, but may herald the development of neovascularisation.

Hard exudates

Leakage of lipids from damaged capillaries leads to 'hard exudates', which, although not involving neovascularisation, may result in permanent visual loss through damage to the macula and fovea. Venous beading and intra-retinal microvascular abnormalities

(IRMAs) are further signs of pre-proliferative retinopathy.

Proliferative Retinopathy
Figure 13.4 Maculopathy in a patient with established background changes, indicated by microaneurysms and blot haemorrhages (photograph courtsey of Dr Sailesh Sankar, Consultant Physician, University Hospital, Coventry).
Ischaemic Retinopathy

Figure 13.5 Pre-proliferative diabetic retinopathy with exudative maculopathy. At least two cotton wool spots indicate retinal ischaemia. There are multiple microaneurysms and haemorrhages, venous beading, and both linear and stellate exudates at the macula, with arterio-venous nipping due to coexisting hypertension (photograph courtsey of Dr Paul O'Hare and Dr Vinod Patel, Warwick Medical School).

Figure 13.5 Pre-proliferative diabetic retinopathy with exudative maculopathy. At least two cotton wool spots indicate retinal ischaemia. There are multiple microaneurysms and haemorrhages, venous beading, and both linear and stellate exudates at the macula, with arterio-venous nipping due to coexisting hypertension (photograph courtsey of Dr Paul O'Hare and Dr Vinod Patel, Warwick Medical School).

Diabetic maculopathy

Increased permeability of the retinal vessels may result in localised oedema, eveninthe absenceofexudatesornewvessels (Figure13.4). When this occurs at the macula it can result in a very acute deterioration in acuity over a period of hours. This complication is difficult to foresee but is treatable, so patients should be aware of the need to report changes in acuity even if a recent screening examination was satisfactory. Exudative maculopathy may occur in apatientwith more advanced pre-proliferative disease (Figure 13.5).

Proliferative retinopathy

The more serious forms of diabetic retinopathy, associated with permanent visual loss, are usually the result of failure of preventive interventions allowing proliferative changes involving new vessel growth (Figure 13.6).

Neovascularisation

Figure 13.7 shows the typical appearance of new vessel formation. These develop in response to vascular growth factors released in response to tissue hypoxia in the basement membrane. In contrast to macular oedema, these changes usually develop gradually and progressively, providing opportunities for prevention. It is unusual for neovascularisation to develop without a recognisable pre-proliferative phase. If preventive measures fail, neovascularisation may result in permanent loss of acuity or visual field.

Sequelae of new vessel growth

New vessels usually arise of the venous side of the circulation and are not normal vessels - they are friable and bleed easily, resulting

Venous Beading Diabetic Retinopathy
Figure 13.6 Proliferative diabetic retinopathy showing new vessel formation and vitreous haemorrhages (photograph courtsey of Dr Sailesh Sankar, consultant Physician, University Hospital, Coventry).
Diabetic Maculopathy
Figure 13.7 New vessels in the peripheral retina, with exudates (photograph courtsey of Dr Sailesh Sankar, consultant Physician, University Hospital, Coventry).

in vitreous haemorrhage and irreversible fibrosis of the surrounding tissues (Figure 13.8). This fibrosis causes traction on the underlying retina, promoting retinal detachment with accumulation of fluid between the neural and pigmented layers.

Further assessment of established retinopathy

Microaneurysms are commonly detected on screening examinations and usually require no immediate action other than attention to risk factors, particularly glycaemic control. Patients should be i

0 0

Responses

  • teija
    What is venous beading?
    7 years ago

Post a comment