Scleral Lens Assessment & Fitting Scleral Lens Clearance
Hello, welcome to another Contacts with Conway.
Today I thought I’d show you a fairly simple method of assessing the height
and clearance of a scleral lens upon insertion. Many practitioners operate, and would like to fit
scleral lenses, without the use of an OCT. Today we'll be covering a slit lamp technique for
assessing the height clearance on the scleral lens on eye using fluorescein.
Prepare Lens with Fluorescein
So, we take our lens, fill to overflowing with saline, take our fluorescein strip
and introduce fluorescein into the bowl of the lens and we're ready to go.
Insert Scleral Lens
Ok so we'll get you to lean forward about 45 degrees from the waist -
that's good. Chin down to your chest, pull your lower lid down with your middle finger. I’m going
to lean over and hold your top lid out of the way and here comes the lens. I’m going to rest
on your hand and you'll feel the cold of the solution then a gentle press as the lens goes on.
Move the hand away and the lens is in.
Assess with UV Light
Ok the first check that we'll make is just to have an overview of the lens to make sure there's no air bubbles and to have an assessment
of the fit. So, we'll take a UV light, like so, and we'll shine here. Now we can see, whilst there's
no bubbles present, we can actually see there's very little central clearance over the centre of the lens.
So, in this case the lens is probably too flat and we're going to select another lens which is slightly steeper.
So, we've changed the lens now we've gone 250 microns higher and we can see now
that there's fluorescein underneath the lens, no air bubbles, so we can proceed with the fitting.
Setting Up the Slit Lamp
When we come to look at the patient under the slit lamp to establish the central clearance
we first of all need to set the slit lamp up. We'll be viewing this time with white light despite the
presence of fluorescein, and we want the narrowest beam. The slit lamp also needs to be set at about
60 degrees from the light source. I also at this stage set the magnification down as
low as possible until we're lined up. Ok, Sue, we'll ask you to sit forward drop your
chin down onto the rest, forehead against the top rest, move forward and looking straight past me.
Ok just checking the magnification is on the lowest possible setting, coming in to
commence focusing. Having got it in the best possible focus I can then increase magnification and zoom in.
Assessing Lens Clearance
Ok we'll now look at the lens under the slit lamp, under white light. We can see the front
surface of the lens glistening there. The lens thickness is 350 microns which shows us that the
tear layer - staying green by the fluorescein - is also approximately 350 microns.
Just behind it, faintly you can see the cornea which is about 550 microns.
So, this is ideal. We're starting off with a tear film of 300-350 microns which will decrease as
the patient wears the lenses by approximately 100 microns. So, at this point we can see we've
got adequate height and it's quite okay for the patient to commence wearing the lens.
Fluorescein Tip
Another tip is that if you have difficulty viewing the front of the lens -look down Sue- we can actually
put some fluorescein -look straight ahead- just wipe a fluorescein strip on the front of the lens
and then we can have a look under the slit lamp and we can see a fluorescein
sandwich which will actually show the lens in clearer detail.
Thank You for Watching
Thank you very much for watching this video. If you like what you've seen then do remember
to like, share and subscribe. If you have any tips or comments you'd like to share with us
then please leave those in the comments box below.