Central Retinal Vein Occlusion

Conclusions

Table 1: The following table summarizes the sensitivities and specificity of the various functional tests.²

Based on our study² (Table 1), for differentiation of ischemic from non-ischemic CRVO during the acute phase, we found the overall order of reliability of these tests as follows:

1. Relative afferent pupillary defect is very reliable in uniocular CRVO, when the fellow eye is normal.
2. Next in order is ERG, which can be performed in all cases, even with bilateral CRVO or with only one eye.
   Combined information from the relevant afferent pupillary defect and ERG, provides the most reliable way of differentiating the two types of CRVO - in as many as 97% of the cases in our study.
3. Next in order of usefulness is the visual field plotting with a Goldmann perimeter, which is better than the visual acuity.
4. Angiography is usually much less useful than the functional tests during the acute stages of the disease. In fact, in our study, it provided definite information in only about 50% of the cases during the acute phase of the CRVO.
5. Ophthalmoscopy was the least reliable and the most misleading parameter. One cannot reliably diagnose whether the eye has ischemic or non-ischemic CRVO based purely on ophthalmoscopy (see fundus photographs in Figure 12).

A study without a clear distinction between the ischemic and the non-ischemic CRVO has little clinical or scientific validity, because, as I mentioned earlier, non-ischemic CRVO is a comparatively benign condition and there is no risk of neovascularization in this type of CRVO. In contrast to that, ischemic CRVO is a severely blinding disease, with a high incidence of anterior segment neovascularization, particularly, neovascular glaucoma.