29 March 2009

More than you ever wanted to know about CRVO

I thought today I'd just paste in the account of my last eye appointment that I wrote up this morning for the CRVO support message board. What is particularly interesting here is the link to the video the founder of the site has made. Talk about altruism. . . . it's one of about six he's posted on youtube to make his seven years' worth of experience with central retinal vein occlusion available to the public. Even medical students praise the results of his research.

A couple of explanations:

IOP = intraocular pressure (the glaucoma test)

OCT = optical coherence tomography, a high-tech method of measuring the thickness of the retina

Friday's appointment was encouraging. Before I go into personal details, though, I want to comment on a change of procedure. Previously I've always had to wait half an hour after the Avastin was administered to have my IOP taken. Now the retina specialist community has decided three quick checks immediately after the injection mean the patient can safely leave right away. (1) A question: with the good eye closed, is your visual field black? (2) Second question, if answer to first was negative: can you count fingers held before the eye? (3) A test: RS checks that the artery is perfused. If so, home you go, eye bandaged, antibiotic drops in hand.

My Avastin injections are always given in a small operating theater. The RS and her assistant scrub up, I lie down, and various antiseptic and anaesthetic steps precede the needle. The Avastin itself, unlike Lucentis, is not extremely expensive. The £550 I pay each time is mostly for use of the room and, of course, the skills of the RS and her assistant.

On this visit, I was pleasantly surprised that, unlike last time, my OCT measurement was again down. Here is the the record of readings. [Occlusion occurred in June 2008, but the first test wasn't done until the three wait-and-see months had passed and I became a private rather than NHS patient.]

A normal reading would be from 140 to 200 microns.

12 Sept 2008 812 microns [at this stage, the image looked like a mountain landscape]

05 Dec 2008 664 [the long time gap between readings 1 & 2 occurred because I was in Kazakhstan]

16 Jan 2009 583

13 Feb 2009 502

27 Feb 2009 594 [it may or may not have made a difference that the usual technician did not take the measurement]

27 Mar 2009 483 [for the first time a slight depression at the fovea could be detected--a good sign]

Again, a reminder that to understand what these readings of retinal thickness at the fovea represent, go to Ken's video:


In the images, I could see the cysts of fluid he mentions and a (shrinking) pool of liquid under my retina.

My visual acuity with the CRVO eye was perhaps marginally sharper than last time. It's always hard to tell, because I can struggle to focus on a letter, identify it correctly, then look away or blink, and only see a blur until I concentrate again. What I do know, however, is that there is a world of difference between what I could see with the eye last summer and what I see now. Details are still hazy but I can, for example, track action on a TV screen that would previously have been nothing but a confusion of blob-like bodies with pinheads on top. The big question, though, is whether the improvement will remain when I discontinue the shots. My RS says for some of her patients it does, for some it doesn't. The good news: no one has ever ended up worse than where they were before the injections.

What especially pleased the RS was the discovery of more collateral blood vessels when she peered in my eye. A second set of fundus photos was taken and these were a revelation. I could see the new vessels she was so encouraged by and the shrinking of hemorrhaging to small points from the big splotches on the September photos. [She confirmed, Bartles, that, yes, the hemorrhaging does go on for about a year.] More disturbing was the sight of the scarring from my laser session. Not a pretty picture. I feel very lucky that only a small area has had to be blasted so far. This patch was ischemic; the damage had already been done and the photocoagulation prevented further leakage.

So there we are. My next appointment is May 1st, when, if progress is continuing and nothing unforeseen has suddenly happened, I'll have another shot. On June 12th, after a month in the States (I'm always sandwiching injections between flights--ideally you wait a week before getting on a plane), I'll have my one-year-post-occlusion check-up. A milestone of sorts . . . .

Carol (London)

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