![]() This is performed by a "swinging flashlight test". Relative Afferent Pupillary Defect (RAPD): The next test which helps us is the relative afferent pupillary defect. If an eye can see only V-4e or no target at all, that eye definitely has ischemic CRVO. Thus, if an eye can see I-2e or has normal visual fields with I-2e, that is definitely in favor of being a non-ischemic CRVO. In contrast to that, in ischemic CRVO, only 8% of the eyes could see all the 3 targets, 63% saw I-4e and V-4e, and 18% only V-4e, and 10% could not see any target at all. Thus, in our study, in non-ischemic CRVO, all 3 targets were seen in 71% of the eyes, and I-4e and V-4e were seen in the remaining 29%, with no eye being unable to see any target or only V-4e. In ischemic CRVO, however, the eye may or may not see V-4e, or may or may not see I-4e, and usually does not see the I-2e target at all (Figure 1). We find that in non-ischemic CRVO, the peripheral visual fields with V-4e and I-4e are perfectly normal, and they may even be normal with I-2e, or the I-2e is still seen in spite of the presence of peripheral visual field defects with this isopter. ![]() We use, in the Goldmann perimeter, 3 isopters: I-2e, I-4e, and V-4e of the Goldmann perimeter. Visual fields plotted with an automated perimeter do not help. Peripheral Visual Fields: We find that peripheral visual fields, recorded with a Goldmann perimeter, give us very useful information in making this differentiation. Thus, our studies showed that if an eye with CRVO has 20/400 or worse vision, then there is about a 90% chance that that eye has ischemic CRVO. A visual acuity of 20/400 or worse was seen in only 19% of the non-ischemic, whereas it was seen in 93% of the ischemic type of CRVO. A visual acuity of better than 20/400 (6/120) was seen in 81% of the patients of the non-ischemic, as compared to about 7% of the ischemic type of CRVO only. Visual Acuity: In our study we found that a visual acuity of better than 20/200 (6/60) was seen in 58% of the non-ischemic, as compared to only 1.7% in the ischemic type of CRVO. ![]()
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