Conventional teaching has been that the visualisation of a Wiess ring implied a PVD (complte or near complete), however surgically when you go into an eye with a well seen PVD, you can often even then, induce a PVD within the posterior pole. Does this mean that the presence of a Wiess ring, is not a predicator of a PVD?
In this patient a Wiess ring was present and is visible at the start of the vitrectomy as a 3/4 circle in mid vitreous. However stndard suction technique to lift the posterior hayloid face able to demonstrate formation of a PVD.
Does this mean that presence or absence of PVD pre-op indeed has no real influence on surgical planning? Or indeed presnce of Wiess ring is not an indicator of PVD, and hence the risk stratification for patients re retinal tears etc may need tobe rethought?
A Higher quality video should be availabale here - if I can figure out how to make it work!
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Actually there is one unit in the UK where the teaching is not to accept the Weiss ring as evidence for a PVD. The policy in this unit is to visualise the posterior hyaloid membrane on slit lamp with or without a 90 D lens. The Weiss ring is considered just a condensation of the gel around the disc which can separate without an actual PVD. It was a difficult concept to get my head around initially but once I did, I found that I was able to identify a few cases where there was a Weiss ring with no PVD identified during surgery. There are 3 possible scenarios- 1. A complete posterior PVD will always have a weiss ring? 2. A Weiss ring may exist without a PVD 3. An incomplete (I mean a scenario where part of the posterior hyaloid is stuck down and left behind over the macula) PVD will not have a weiss ring but the discontinuity in the posterior hyaloid membrane can be picked up on biomicroscopy.
ReplyDeleteHi, I agree with your comment. Usually this can be picked upon biomicroscopy, but sometimes it is almost impossible to be sure on clinical exam, especially in high myopes.
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