How a Prosthetic Eye is Made
We require that adequate healing take place before fitting. Schedule permitting, we fit the prosthesis at six to eight weeks after surgery.
Using alginate, we take an impression of the eye socket After removal from the socket, the impression is encased in plaster of Paris.
The impression material is then removed from the mould and molten wax is poured into the mould,This is allowed to cool and harden.
What we obtain is a wax piece that constitutes a model for the artificial eye.
The wax allows us to make changes for comfort as well as opening eyelids to match the companion eye.
We fill up that plaster model with the wax and then we clamp it together and let that cool.
So we can take it out of the plaster mould and clean it up, get rid of any rough edges on it, polish it up a little bit, and then we can try that into the socket of the patient to see how it fits.
At that stage we need to see if it's a bit too big, we can carve a bit of the wax off to make it smaller.
If it's a bit too small we could add a bit until we're happy that we've got the shape that fits the socket the way we want it to do.
What we need to do is measure the iris diameter, so we know what size it is.
We paint onto the little black discs that we have in different-sized diameters, so we measure the diameter of their iris and we get the closest-matching black disc.
And then we'll paint directly onto that black disc. So we're looking at the patient's colour, then we need to mix the colours to paint those colours onto the black disc to get the correct colour of the iris.
We say a blue eye or a brown eye but if we look closely at the eye there are lots of different colours within that eye.
So we got to match all of that, paint all of that, mix up the colours, to get as close a match as possible. Once the plaster's set we can take it apart, take the impression out, and then we need to fill it with wax.
We've got a special scleral wax, which is a carvable wax.- Then what we need to do is a mark on the wax where the iris should be.
Once we're happy with that, we then need to get the iris colour that we've painted and we glue what we call a cornea unit onto the front of that and that's got the corneal bulge, the dome over the front of it, that magnifies the colour up.
And that also has a little peg that comes out the front, which gives us the gaze of the eye, so we can adjust the angle of that until we're happy with the gaze. Then just wax that painting into the wax so it's all nice and smooth and there are no edges on it. And we need to take that wax shape with the iris and we make up a different plaster cast, so we're using a harder plaster in a metal flask.
Once that's set we can take it apart so you've got the two halves, and then you've got the painting with the little peg on it. So you can take that out, remove all of the wax, clean up the painting, and then using the little peg you can insert that back into the hole that it's made, so you're getting that in the right position.
We then mix up the acrylic, the plastic. Once it's ready you can then pack that into the mould, you clamp it under pressure, you heat it overnight and it goes hard, like plastic.
Then the next day you can take them out of the flask, then you can polish flat over the iris and add some highlighting to the colour, so it gives it a bit of depth. So we can a bit of extra colour.
What we also do on the white of the eye that we've now created, we're going to add some staining onto the eye, because nobody has just a plain white eye, there's a little bit of possibly yellow, brownish staining on there, so we'll add that. And then we'll add the veining onto the eyes as well, so the veins are embroidery thread, red embroidery thread teased out into tiny strands and then you stick that all on the surface.
We let that dry in the oven and then when that's dry we can put that back into our two-part mould, but where we've ground off an even amount all over the front, we're going to replace that with clear acrylics and then we can trim it up, polish it all up so it's all nice and smooth and then it's ready for the patient to come in and be supplied with their artificial eye.
The most satisfying part is patients when they get their eye.
If you've done a good job they're happy, and I know it sounds a bit corny but you've changed their lives. It's – that's, yeah, honestly the best part of it that you know you've helped somebody out.