How is the anterior chamber entered during trabeculectomy?

Updated: May 18, 2020
  • Author: Maria Hannah Pia Uyloan de Guzman, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Answer

Answer

Anterior chamber entry

The internal scleral flap dissection should extend all the way to the peripheral cornea to ensure that the sclerostomy will be made well anterior to the iris plane. This is especially important in eyes with shallow ACs to prevent the iris or ciliary body from becoming incarcerated in the sclerostomy. Thus, the term sclerostomy has become a misnomer because the tissue excised from under the anterior limit of the scleral flap is actually peripheral cornea. See the image below.

Diagram showing the ideal extent of internal disse Diagram showing the ideal extent of internal dissection under the scleral flap and the ideal extent of the flap sides (external).

The AC is entered at the anterior limit of the scleral flap using a blade. The blade should be angled more posteriorly than the plane of dissection of the flap. Avoid causing the wound to gape during this step to prevent excessive AC shallowing. See the image below.

At the anterior limit of the scleral flap the blad At the anterior limit of the scleral flap the blade is redirected parallel to or towards the iris (green dashed line arrows, left). The "sclerostomy" is actually corneal tissue anterior to the trabecular meshwork/Schlemm canal (right).

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