The College of Optometrists

hi just would like to know that if someone presents in practice with a peripheral ulcer on cornea that was not very painful and they are a CL wearer, there are no signs of infiltrates or inflammation then can we supply chloramphenicol 0.5% or do we send them to GP or HES?

also there are lots of ways of prescribing prisms to alleviate symptoms of uncompensated heterophoria but is it better find D and N phoria with M rod and Wing then to work out AC/A ratio and based on the calc give the prism or to just give what the Mallett unit finds?

am very unsure of what the examiners would expect us to do but would very much appreciate any suggestions

thanx

I would not aim to treat and corneal infection unless I had alot of experience. All corneal infections start small and innocent looking. An ulcer is simply a non-self limiting corneal infection. Chloramphenicol is not licenced to treat corneal infections.

So if someone turned up with what looked like a corneal marginal ulcer - I would phone eye casualty and get them up there for treatment. You can never tell whether the causative infection would be resistant to antibiotics and you can never tell whether the marginal ulcer is self limiting but an ulcer in the making.

So, I would by-pass the gp -yes.

You only use prism if there is an uncompensated phoria giving symptoms. Maddox rods, wings etc don't give you the information on how compensated the phoria is -so are not useful to giving prism. As far as I am aware maddox rods and wings are not used anymore, except in the rarest cases.

No, do it like this: you do a careful cover test and you detect a horizontal phoria at near. Use your fixation disparity near Unit to get the prism. Alternately, you could use a variation on fusional reserves. You will remember that the phoria is compensated by fusional reserves that hold the picture in single vision. If you stress both fusional reserves - the weakened one will break down to diplopia. You can do this with a 3 dioptre prism (horizontal) or 1/2 dioptre prism (vertical).

You flip the prism like a crossed cyl and ask which side is better - px responses will give you the direction and power quite quickly. Give it a try. It is described in a book by Calder Gillie.

Or - you could add prism to your cover tests until the recovery is fast and smooth.

I suppose, in practice I combine all three.

Please remember, that prism is not a hard and fast thing - the person taking 1 in EE will easily take 2 in EE as well. So you are dealing with a very plastic measurement - it is wise to start with minimum prism.

does that help?

If you need more - please ask!! Steve sorry for the delay - I have been away.