This patient had a congenital optic nerve pit and presented to us with a Central serous retinopathy or CSR. After the completion of core vitrectomy, trypan blue was used to stain the ILM and the ILM was peeled carefully using ILM peeling forceps. Extra care was taken while peeling the ILM over the macula. A light laser was applied around the pit to prevent the fluid from crossing over to the macula. The overall fundus was assessed and air fluid exchange was done.
Surgery location: on-board the Orbis Flying Eye Hospital in Chittagong, Bangladesh
Surgeon: Dr. Manish Nagpal, Retina Foundation & Eye Research Centre, Ahmedabad, India
(To translate please select your language to the right of this page)
Dr. Manish Nagpal: This is a case of an optic nerve pit with CSR. Which means that the patient has a congenital optic nerve pit which at some point in the lifetime of the patient collects fluid under the macula, which leads to decreased vision for the patient. Now, we are ready to put the cannulas and now inserting the trocar, and we will now insert the infusion cannula through that.
All three are put at 4 millimeter as this is a phakic eye. Now, we are ready to start the surgery. The light pipe goes through one and the cutter goes through the other. The white filled viewing lens is put. You can see the congenital optic disparate on the temporal margins of the disk, and an altered reflex of the fore here which is because of the fluid collection and the changes on the macula.
The vitrectomy has started. We are removing the vitreous using the cutter in the central part of the vitreous cavity at this stage. The light pipe is directed such that one can see the reflex of the vitreous when the cutter is able it cut it. The port of the cutter is usually kept facing towards us or in a slant so that we can see where we are cutting and not be blind to the area where the cutter is moving.
Once core vitreous is cut, we are ready to assess the hyaloid attachment. So, we put the triamcinolone dye. We let it fall over the macular area, as you can see, and this will stain the hyaloid. After it has fallen over the macula, we take the cutter and remove all the residual floating dye. You can see that all the residual flow is being aspirated by the vitreous cutter.
And once the residual dye has gone, you will see two halos. A larger halo within the arcades and a smaller one over the disk. This is how the normal attachment of the hyaloid is there at the macula, at the rim of the disk, and also within the macular area within the arcades. So, once all the residual dye is gone, then we use a high aspiration mode on the cutter and start pulling from the margin of the disk.
You can see that we have entangled that vitreous and we are pulling it. And you can see the whole complex moving anteriorly. Now, this is a sign of a good hyaloid detachment, which is what we wanted to accomplish. And then slowly you can increase the circumference of that detachment. You can go to each rim and then pull towards the periphery so that you can get a good hyaloid detachment all around.
All the residual dye crystals are being aspirated. And this also allows us to see some more of the peripheral vitreous which gets stained by these residual crystals. And so, we remove all of that as well. We remove the residual crystals from the margins of the disk also. Once we have removed all the vitreous that we can visibly see, then we plan to inject the dye to stain the hyalin. Now, here we are injecting the trypan blue dye other the macular area.
You can see that the dye has spilled over the macular area. And then we have to wait and allow it some time to stain. Unlike the brilliant blue dye, which stains much better, the trypan blue is not so good at staining the hyalin. Once we have injected the dye, we let it be for a minute or so and then we start aspirating it with the cutter, all the residual dye which is floating in the vitreous gets aspirated. So, initially the fundus becomes very dark blue and slowly you start to see the glow of the fundus back as the dye is removed. Again, this dye also helps us see some of the peripheral margins of the vitreous which it lines up and you can remove those areas.
The brilliant blue stains very well. In this case we had access to trypan blue. And the blue of the trypan blue is not as visible as what is seen clearly with the brilliant blue. But here we will make do with the trypan blue. After this I’m ready to start the ILM peeling. For this, I change from a wide free lens to a high magnification lens so that I can have a very good stereoscopic view of the area that I’m going to peel.
So, now you can see that I have an excellent view, which is very magnified, as compared to what you were seeing before. And I’m ready with the ILM peeling forceps. You can see this forceps has very fine platform which is allow us to pinch and find the edge of the ILM so that we can start the peeling.
Now, you can see that even though the color is not visible, you can see the parchment like membrane which gets picked up by the forceps. And when we start moving, you will see the filamentary movement that confirms that there is an ILM there. Since the color has taken up not so well, we have to do this pinching multiple times to make sure that we have the ILM in the grasp of the forceps.
You have to be very careful here because you don’t want to pinch too deep, because every time you pinch deeper you will, obviously, injure some tissue in the macular area and you don’t want to do that. Here I just disentangle some of the residual ILM fibrils which had aggregated at the forceps edge using the light pipe.
I’m still looking for the best possible grip. And so, I’m trying out different places. And now you can see that I have a good grasp and a small sheet gets elevated. It’s a thin, shiny sheet which is visible. And you can also see the movement as we peel the retina underlying. You will see the stretching part, which confirms that the ILM is being peeled from there.
Our aim is that we go circumferentially and take it over the macular area. And one has to be careful, because here the macula is very thin. And the last thing you want to do is deroof the macula or the fovea while we move the ILM. So, one has to do this very gently. And you can also see some of the residual stain trypan crystals are lining the peeled ILM. Which is a confirmation that you have peeled the ILM from over the macular area.
Now, we’re just extending a bit of that ring. I typically peel about 1.5 to 2 disc diameters of ILM around the macular area. Some surgeons prefer it wider. But most of us peel about this much.
So, you can see another small circumference of the ILM also being moved just to increase the surface area of the peeled area. This is the area of the pit. In fact the dense collection of the triamcinolone crystal is within the pit. So, we’re just assessing that. The peeling part is over.
And now we’re taking a laser, a very light laser, which we will do to the temporal margins of the rim. And before we can apply this light laser, we usually titrate it in the periphery to make sure that we don’t do a dense burn to the temporal part of the disk. Because then we may cause a larger damage to the nerve fiber layer. So you can see that we are just doing a few test runs in the periphery. And once we see a very mild gray blanching is where we bring the laser. So, here you can see a mild blanching of the gray burns and not a thick white burn, which is what we don’t want to have. So, two rows of these burns are more than enough.
The aim of this is to indicate a very light barrage which would prevent any passage of fluid from within the pit towards the macula, where the concept of doing this procedure lies. So, we finished the laser here. So the peel is over, the laser is over. Now we shift back to the wide free lens just to assess the overall from this view. And also do an air fluid exchange. So, now we will bring in air which will replace the fluid. You can see an air bubble coming in. And now slowly the air bubble will replace the fluid from the top to the bottom. Gradually I will move the cutters port towards the disk. And you can see the reflex changing. The fluid is being replaced by the air. And you see a complete fluid gas exchange happening at this stage.
At this stage we assess the periphery so that we make sure that no iatrogenic breaks are formed during the PVD creation on any part of the procedure. And once again, look at the central area. After this, we inject gas into the cavity. While injecting gas, we switch off the infusion. The air coming from the infusion. And the gas is replacing the air inside.
After that, we remove the cannulas one by one. As soon as we remove it, I usually massage it with an ear bud. This allows the wound to get time to regain its elasticity. It has been stretched open by the cannula during the course of surgery. As soon as we remove the cannula sometimes vitreous fluid can come out. The best thing is to do a little bit of a massage on that which allows the wound to get back toes normal shape. So, we do that one after the other. Each of these cannulas. And we wait for 10-15 seconds after removing the cannula and massaging it.
And you can see that as soon as we remove the ear bud, we check that is there any leak or not? That’s when we are certain if there’s a need for a suture at this stage. And the best thing is to assess very carefully at this stage. Because otherwise you could have a hypotony the next day if there is a wound leak. We also pour some fluid over it. This also allow us to double check if there’s a leak. You will see some air bubbles coming as soon as the fluid goes over the surface of the eyeball. So, it allows you to double check and ascertain that there is no leak.
So, this is the end of the case. Thank you.
January 11, 2018