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25g needle bending

Q:

When McLean originally published this technique (Ophthalmology, 1986), it was with a regular, non-bent 20g needle. The advantage of using such a large needle is that there is zero chance of perforating. When Peter Laibson discussed this technique at the AAO, he suggested maybe using a smaller (i.e. 25g) needle. With that, unbent, folks experience perforations. Then, one of his more brilliant fellows, Roy Rubinfeld, invented the “Rubinfeld anterior stromal puncture needle”, which was bent like a cystitome.  If they are really not available anymore I will probably go back to the original 20g needle. Sromal puncture is ESSENTIAL in cases of post-traumatic (non-EBMD related) recurrent erosions. MUCH better than simple debridement, burr polishing, etc., as it addresses the underlying pathology appropriately.

 

Randy

Highland Park, IL

A:

It’s pathetically easy to bend the tip of a 25g needle using the protective cap, so just the sharp point is bent at a right angle. No need to worry about not being able to buy a special needle

I learned this tip from Claes Dohlman at Harvard

Sill don’t know why you wouldn’t just do a LASEK if there’s any Rx (as there is 90% of the time) as it works better and gets rid of the Rx also and doesn’t cause starbursts

Emil William Chynn, MD, FACS, MBA

Harvard/Columbia/Dartmouth/NYU/Emory-trained

Q2:

It is easy to bend the tip, Emil.

Working with Ralph Eagle at Wills we found it was not at all easy to make the bent tip of a consistent length.

We tried hard.

Especially in erosions in the pupillary space, it mattered in our in vivo and in vitro work.

Deeper penetrations caused more scarring.

Non-standardized needle:

Standardized needle;

Both at roughly same postop point. Again NFI. -Roy

Q3:

Emil:

Completely agree that it is very easy to bend needle with protective cap as you slide it out and this is how I do it for cutting sutures and for stromal puncture.  

I do not agree that it’s a good idea though to do PRK or Lasek at the same time as treating ABMD because I often find that the epithelium on these patients is thickened and abnormal and when you remove it by doing a simple superficial keratectomy there is a significant change in the refraction when it heals.  10-15 years ago I used to combined PRK with ABMD treatment and got a lot of wacky outcomes.  Stopped doing that and now that I have OCT imaging of the epithelium I know exactly why those wacky outcomes occurred.  Epithelium on these patient is thickened, highly modeled and often irregular.

Steve

A by Dr. Chynn:

All you have to do is back off on the Rx and be conservative in what you enter into the laser to treat

By doing so I’ve been within .75D every time. No wacky outcomes or bad over corrections 

Emil William Chynn, MD, FACS, MBA

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