Neovascular glaucoma
Introduction
Neovascular glaucoma (NVG) is a blinding, intractable disease, difficult to manage and often resulting in disastrous visual loss. For a logical understanding and scientific rationale for management of any disease, one first has to know the basic issues involved and the scientifically valid information available on the disease. To prevent or reduce the visual loss caused by NVG, the first essential is to have a high index of suspicion of its development, i.e. to be aware of the various ocular diseases in which it can develop. Once it develops, early diagnosis and rational management are important to minimize the visual loss. Therefore, the objective of this review on NVG is to discuss its causes, pathogenesis and pathology, methods of early diagnosis and finally management.
Section snippets
Causes of NVG
These can be divided into two categories: (a) the most common causes and (b) uncommon causes.
Pathogenesis and pathology of NVG
There is a large volume of literature on the subject of angiogenesis and NV, it is beyond the scope of this discussion. However, a brief summary of the most pertinent information concerning ocular NV and NVG, especially to its clinical aspects, is warranted. Chen et al. (1999) reported that increase in the inflammatory cytokine interleukin (IL)-6 in aqueous humor correlated spatially and temporally with the grade of iris NV in patients of NVG secondary to CRVO. They postulated that the
Diagnosis of NVG
Advanced NVG is straightforward to diagnose. However, early in the course, NVG may present subtle findings and one must have a high index of suspicion of its development in the settings of various diseases discussed above (particularly ischemic CRVO, diabetic retinopathy and ocular ischemic syndrome). In addition, a careful examination of the iris and angle of the anterior chamber is essential, before the pupil is dilated and any drops put in the eye. Once the pupil is dilated, it may not be
Differential diagnosis
From time to time, NVG has been confused with other ocular conditions. For example, eyes with severe non-granulomatous uveitis with dilated iris vessels and proteinous aqueous and high IOP can be misdiagnosed to have NVG. There are some eyes where normal iris vessels are seen easily, particularly in blue eyes, which may be mistaken for iris NV or even angle NV when the vessels are seen near the root of the iris. Eyes with carotid-cavernous fistula erroneously may be diagnosed to have NVG
Management of NVG
This is highly challenging, unpredictable, difficult and controversial. It involves several considerations, including the following:
- 1.
Most importantly, it is essential to have a high index of suspicion of its development in the various diseases discussed above (particularly ischemic CRVO, diabetic retinopathy and ocular ischemic syndrome). Early treatment of those underlying diseases can reduce the development of NVG.
- 2.
A high index of suspicion of its development is also important for early
Conclusions and future directions
NVG is a severely blinding disease. To prevent or reduce the extent of visual loss caused by NVG, the first essential is to have a high index of suspicion of its development; if NVG develops, early diagnosis and aggressive control of high IOP is crucial to minimize the visual loss. The most common diseases responsible for development of NVG are ischemic CRVO, diabetic retinopathy and ocular ischemic syndrome. In the management strategy, the first priority should be to try to prevent its
Acknowledgments
I am grateful to my colleagues Drs. Wallace L.M. Alward, Young H. Kwon and Stephen R. Russell for valuable suggestions.
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