Notches and Flanges: Next Pupil-Dilating Device
Narrative Responses:
Purpose
To evaluate two new designs of Pupil dilating devices. To test the efficacy of the new concept of Notches at the corners of a Square or Hexagon shaped, single plane, closed ring device.
Methods
The closed ring devices are made of 5-0 Nylon, disposed entirely in a single plane, with alternating notches and flanges, notches being used to engage the pupil margin. 6.5 & 7 mm Square an 6 & 7 mm Hexagonal device used. Inserted with 23G Forceps or Injector, alternate flanges are placed above or below the pupillary margin. 6.5 mm square and 6 mm Hexagon used when the horizontal white to white corneal diameter less than 10 mm. Incision size, insertion, removal, pupil size, rhexis size, stability, ease of instrumentation, Pupil shape on removal & complications were evaluated.
Results
Device used in 33 consecutive eyes with non dilating pupil (less than 4 mm) or larger pupil with history of IFIS in the other eye. Square used in 17 eyes and Hexagon in 16 eyes. Incision size 0.9 - 2.2 mm. Device insertion and removal easy with short learning curve. Average pupil size 5.7 mm and average capsulorhexis 4.9 mm. Phaco probe movement and side port instrumentation was unhindered. A round pupil was achieved on removal of all the devices. For a given pupil dilation, Hexagon required is smaller than the Square. No device related complications were noted.
Conclusion
New devices effectively dilate the pupil, are easy to use for Phaco & sub 2.2 mm MICS, and overcome limitations of Malyugin and Oasis rings which have bulky two plane structures at corners with gaps which snag the incision and cannot be inserted through sub 2.2 mm incisions.