The College of Optometrists

when doing humphriss i.e. using a +0.75D, are u supposed to offer minus lenses or just push the plus?

if just offering plus, is this humphriss still??

pls help......

Erm.... i think it makes sense just to push the plus. Why would adding minus help as cant make your eye more minus than would be when accom relaxed, so adding minus would just stimulate accommodation at this point as wont be underminused at start of binoc balance. Elliot book unclear on this though.

Did that make any sense...?

difficult to get a definitive answer on this one. Personally, I feel that binocular balance does more than just push the plus - if you have slightly overminused one eye, and underminused the other, it gives the patient the chance to even this out subjectively. in this case, if I was a young myope, I would prefer to have the extra minus in one eye, rather than the extra plus in the other - hope that makes sense!!

I think you should have a clear idea what you're expecting from your binoc balance before you do it - if you already suspect pt has not accepted full plus, then by all means push the plus and avoid giving minus. If you were happy with your monocular ref, and the patient expresses a clear preference for the minus, i'd give it, though not more than 0.25DS

I appreciate none of this is a nice snappy answer to an exam question, but hopefully it's helpful in real life!!

Lisa

don't forget most people have a depth of focus of at least 0.25 - so can be over plussed by 0.25 anyway. So adding minus is no big deal anyway. All you are trying to do is to get both eyes equally innervated. There is no big horror in going a bit minusy. Also your room is smaaler than infinity - and lots of people like a bit of minus t osharpen the distance. No two people are the same.

when doing humphriss you balancing the eyes. Therefore if they are not balanced one eye will accept minus or the other eye will accept plus.

You should only use plus as theres a chance of over minusing as patients accept minus much easier than the plus.

if you do over plus them then you will sort this out with your binocular add at the end.

if u consult bennett and rabetts it gives a good explanation, to using + and - 0.25, thats wot i do and it works well!! if balanced px will accept -0.25 initally and on repeating 1/2 steps will then accept + proving that they are indeed balanced.

Its all about visual comfort surely!

Yep, i agree with lead, there is an excellent chapter on binocular balancing in bennet and rabetts. Two methods.

1) humphriss - where u use both pus and minus

2) humphriss modified - most widely uses, works just as effective and saves time!

assuming you always do a binocular add at the end...