3103: GATT using retroillumination
Operating Surgeon – Jonathan Tijerina, MD & Supervising Surgeon – Elena Bitrian, MD
36 yo patient with a history of developmental delay, chronic eye rubbing, and bilateral PKPs for keratoconus complicated by corneal hydrops. He developed steroid response glaucoma in the left eye after treatment for an episode of acute graft rejection with topical, sub-tenons and oral steroids which stabilized; however, ultimately the graft developed recurrent bullous keratopathy, IOP above goal on 4 agents and was referred to the glaucoma service for optimization with phaco/ MIGS prior to considering repeat keratoplasty. We wanted to avoid a subconjunctival implant/ incisional surgery if possible due to the history of eye rubbing.
After a challenging phaco making use of the endoilluminator/ light pipe to facilitate a visualization through the corneal opacity (0:05), we encountered a very opaque gonioscopic view to the angle when we attempted to do so with traditional operating scope lighting and gonio prism (0:06). Having used the light pipe for the phaco we decided to try to backlight the trabecular meshwork by placing the light pipe external to the AC on the sclera opposite our main incision and reducing paraxial lighting. This demonstrated a dark outline of the TM, a structure we have come to call the “trabecular silhouette” which was not visible prior to this lighting adjustment (Arrow, 0:25). We were then able to successfully canulate and perform the goniotomy for nearly 360 degrees. We also visualize the trabecular cleft or characteristic bone-white back wall of Schlemm’s canal using this technique to confirm an effective goniotomy (Arrow, 1:25). Of course, we make sure to suture our wounds due to the history of eye rubbing and developmental delay. We have since used this technique in many cases of MIGS with corneal opacity or edema, as well as pediatric cases with Haab striae and patients with normal corneas but lightly pigmented trabecular structures (demonstrated 1:49 – 1:58). It is helpful not only for GATT but blade goniotomies and trabecular stenting when visualization is challenging. https://jamanetwork.com/journals/jamaophthalmology/article-abstract/2851883
