“PVR is from the devil!”, one of my eye buddies frequently declares with feeling, whenever the subject is broached. She should know. Her eight-year-old son has had five retinal detachments in his left eye and undergone over thirteen surgeries as a result of PVR. Currently, he’s lost almost all vision in his eye and is only able to see some motion and colours. PVR is the cause of my five re-detachments following the initial surgery to fix my first detachment back in April 2014. PVR is a curse, and those three little letters strike fear into the heart of any RD patient, for we know the devastation and utter misery that it can cause.
“So what exactly is PVR?”, I hear you ask. When a friend asked me this question recently, I simply answered, “Oh, it’s the thing that keeps making my retina detach – it’s like bad scar tissue, which keeps pulling the retina off again”. That seems the simplest and quickest way of explaining it to someone who knows little about eye issues, but even the reference to scar tissue can be a bit confusing. You see, there’s the ‘scar reaction’ which occurs after laser or cryotherapy, which basically welds the retina back together. I think of this as ‘good scar tissue’. In contrast, I think of PVR as ‘bad scar tissue’. I did once have a conversation along these lines with a retinal surgeon, and he agreed, “Yes, I see what you mean”, when I explained my confusion about the difference between the scar reaction of the laser and the scar tissue of PVR.
Okay, so let’s get down to the complicated bit… PVR (or proliferative vitreoretinopathy) is a disease which is a major complication that can occur following retinal reattachment surgery. It occurs in 5-10% of all rhegmatogenous retinal detachments (retinal detachment as a result of a tear in the retina). Although PVR can be treated with surgery and reattachment of the retina can be achieved, the visual outcome is often extremely poor and PVR is the main cause of failure of retinal reattachment surgery.
Retinal detachment happens when a hole or tear in the retina results in vitreous fluid seeping through the hole and getting underneath the retina, pulling it away from its place at the back of the eye. Imagine the retina as being like a wallpaper, lining most of the inside of your eye, apart from a small section at the front. Now think about when you strip wallpaper off a wall, and how you use an instrument to create a tear in the paper and water to soak through and lift the paper off the wall. If you think of the wallpaper as your retina and the water as the vitreous fluid inside your eye, that’s sort of what’s happening when a detachment occurs. Of course, technically the room would be filled with water, but that’s just weird. ANYWAY… during the process of retinal detachment, the vitreous fluid comes into contact with RPE cells (retinal pigment epithelium) just below the retina. (In our wallpaper-stripping example, I guess this would be the brickwork, or maybe the mortar.) As a result of the retinal tear, the RPE cells are able to migrate out into the vitreous. The cells then proliferate and form fibrotic membranes (or scar tissue), which can then contract and pull at the retina, causing it to re-detach.
To complicate matters further, there are different types of membranes which can form, depending on which side of the retinal layers the cells settle in and which other cells are involved. One type forms like a sheet and doesn’t necessarily affect retinal reattachment surgery; the other forms as thick membranes which cause traction, thereby pulling at the retina. These need to be removed before the retina can be reattached. Naturally, these are the ones which I have. [Pauses to wail in loud misery.] Since reading up on all this, I now understand why I’ve had three retinectomies. A retinectomy is the procedure whereby the surgeon physically cuts away the part of the retina which won’t lie flat due to PVR. Nothing has ever caused me to assume such a death-like pose as the moment I heard the surgeon utter the words, “Can I have the cutter, please?”, during my fourth surgery under local anaesthetic.
So why do only 5-10% of RD patients get struck down by the curse of PVR? Although it really does often feel like some kind of terrible punishment for some unknown dreadful crime I’ve committed, I’m assured that this isn’t the case. From what I’ve read, it seems that PVR is more likely to occur alongside any of the following circumstances: a large retinal hole or tear, a macula-off detachment, vitreous haemorrhage, aphakia (no natural lens in the eye), a long period of time between detachment and surgery, multiple surgeries, and poor surgery itself. My initial detachment was macula-off and I waited two days for surgery, but it’s pretty normal to have a wait once the macula has detached as a delay of up to a week doesn’t affect the final visual outcome. My current consultant (who just happens to specialise in PVR) explained to me that once someone has PVR they will always have it. From what I can gather, the effects of PVR – particularly in the more severe cases, which mine is – can clearly be seen on the retina, but even if the surgeons are able to remove the worst of it and reattach the retina, there will still be cells floating around in places that they shouldn’t be within the eye. A further huge problem is that PVR is a process, and inflammation can aggravate that process. So every surgery unavoidably causes inflammation within the eye, which then risks activating the PVR once more. It really is a vicious circle. PVR is the enemy of the RD patient, and it needs to be beaten. Just as Jules Gonin made a massive breakthrough in RD surgery by discovering the importance of locating the retinal tear (have a read of my earlier post, Hurrah for Jules Gonin if you’re wondering what I’m talking about here), now we need a modern day Jules to crash through the PVR barrier and bring hope to those of us who live with its curse.
Note: Please note that I am not an ophthalmologist or an expert in PVR; I have written this simply as a frightened patient afflicted with PVR. For anyone interested in doing some further reading on the subject, you can find a selection of some of the articles which I’ve found helpful below. If any of my eye buddies have any interesting/useful information to add, it would be great if you could share it by including it as a comment below. 🙂