NVE are defined as any abnormal collection of leaking vessels occurring on
retina more than one disc diameter from the rim of the optic disc.
They normally occur in the post-equatorial retina with a predilection for the
vascular arcades. However, NVE in the nasal retina also occur and may be
easily missed. Untreated NVE in particular are associated with tractional
retinal detachment, hence the importance of their early detection and
7.2 Treatment of NVE
Treatment is the same as for NVD ie by pan-retinal photocoagulation (PRP).
Areas of retinal ischaemia as determined by fluorescein angiography should be
preferentially treated and a more peripheral application of laser burns helps to
preserve more of the visual field, while being equally effective.
7.2.1 Early NVE
Early NVE responds to a basic PRP as NVD (see above (Figs 23a and b)
7.2.2 Progressive NVE
NVE may present as relatively advanced abnormal vascular structures
(Figure 11) which require a full PRP which particular attention being paid
to the areas of ischaemic retina in the proximity of the NVE (Figure 24a and b).
Fig 24 NVE treated with PRP (a),
resolution of NVE (b).
7.2.3 Florid NVE
NVE may develop rapidly and in more than one site (Figure 12 and 23).
This condition required aggressive management as for florid NVD, attention
being paid to the regions of ischaemic retina.
7.2.4 Non-responding NVE
On occasion, NVE may not fully respond to PRP and persist as foci of leaking
vessels. Attempts should be made to close down such vessels with the
application of further laser, particularly around the vicinities of the NVE, in a
series of short focal applications. The active vessels should be monitored
every 2-3 weeks.
7.2.5 NVE with gliosis
NVE particularly on the vascular arcades may form firm vitreoretinal
adhesions which promote the development of gliosis (Figure 25). Such
lesions may act as the focus for traction on the retina which, if treated
too aggressively with laser therapy, may develop retinal holes and lead to
rhegmatogenous retinal detachment. Application of the laser some distance
from the site of the gliotic NVE may help to induce regression of the new
vessels. If the condition progresses however, for instance with vitreous
hemorrhage or retinal detachment, vitrectomy may be required.
Fig 25 Inferior arcade NVE with
7.2.6 NVE with vitreous haemorrhage
NVE are frequently the cause of vitreous haemorrhage but the site of
bleeding may be masked by the blood (Figure 18). NVE may be tracked
to the point or tip of a subhyaloid haemorrhage. NVE with vitreous
haemorrhage should be treated as for NVE with vitreous haemorrhage.