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Silicone oil-induced secondary angle closure another application for single-pass four-throw pupilloplasty
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Silicone oil is one of the most commonly used tamponade agents in vitreoretinal surgeries. There are multiple adverse effects and complications of silicone oil; one of these complications is secondary angle closure. This can occur commonly when combined with scleral buckles, which can cause congestion and anterior rotation of the ciliary body, resulting in angle closure. Other mechanisms that can cause angle closure in eyes injected with silicone oil are pupillary block glaucoma, closure of peripheral iridectomy, inflammation and peripheral anterior synechiae. The end result is narrowing of the angle and development of adhesions between the iris and anterior chamber angle structures. This eventually leads to an increase in IOP and possibly glaucoma.
Pupilloplasty is the surgical repair and reconstruction of the pupil. Its application has been cited previously for congenital defects, iatrogenic trauma, glare, photophobia, traumatic mydriasis and optic capture. Pupilloplasty has also been used for breakage or prevention of peripheral anterior synechiae. We describe an application of single-pass four-throw (SFT) pupilloplasty to prevent or treat synechial angle closure in eyes that have undergone silicone oil tamponade complicated by angle closure with increased IOP (Figure 1). Such cases have in the past been treated with either trabeculectomy or glaucoma drainage devices. The difficulty faced with such an approach is the high failure rate of conventional trabeculectomy and the extensive approach involved with placement of a glaucoma drainage device.
Preoperative evaluation of these patients must include visual acuity, anterior segment evaluation, fundus evaluation, applanation tonometry, gonioscopy, anterior segment OCT, and OCT of the disc and retinal nerve fiber layer. Preoperative control of IOP should be undertaken with topical medication or systemic route as indicated. In eyes with silicone oil present, a combined approach is probably more compliant.
After preparation and draping, the surgical management involves removal of silicone oil, then a trocar anterior chamber maintainer is placed 1 mm from the limbus through displaced conjunctiva, and fluid infusion is initiated in the anterior chamber. Alternatively, the procedure can be performed with infusion introduced from the pars plana site. Using intraocular microforceps, the iris is gently pulled away from the periphery to break the formed synechiae in all quadrants (Figure 2). A 10-0 Prolene suture is then introduced through clear cornea and taken through the iris on one end. At the other end, a 26-gauge to 30-gauge needle is taken through the paracentesis and then through the iris. The 10-0 Prolene suture is railroaded into the needle and externalized through the paracentesis (Figure 3). Using a Sinskey hook/dialer, the distal end of the suture is looped, and the looped suture is brought out of the paracentesis using microforceps. The proximal end of the suture is passed through this distal loop four times (Figure 4). This constitutes the four-throw part of the pupilloplasty.
Source: Ashar Agarwal, MS, FRCS, Priya Narang, MS, and Amar Agarwal, MS, FRCS, FRCOphth
Both ends of the suture are pulled to internalize the knot, and the suture ends are cut with microscissors. The same procedure can be repeated in other quadrants of the iris as desired. Intraoperative gonioscopy can help confirm that the angles have been opened. The eventual result is that of a mechanically miotic pupil that is stretched and prevents the subsequent formation of peripheral anterior synechiae, thereby activating the existing drainage mechanism of the angle and lowering IOP (Figure 5).
Postoperative examination should include visual acuity, anterior segment evaluation, fundus evaluation (which is still possible with SFT pupilloplasty), applanation tonometry, gonioscopy and anterior segment OCT.
The advantage in performing a surgical pupilloplasty is the opening of angles after breakage of the peripheral anterior synechia that leads to a decrease in IOP (Figures 6 and 7). The specific advantage with performing an SFT pupilloplasty is that it involves the passage of the suture needle only once through the anterior chamber. This indirectly translates into less inflammation due to minimal handling of the already-inflamed iris tissue. In a state in which conventional trabeculectomy fails often and repeated procedures have to be undertaken without a satisfactory result, here we have a combined procedure that fixes the causative problem of closed angles and achieves normalization of IOP via the natural process of aqueous drainage. Nevertheless, it is essential to state that surgical pupilloplasty would be rendered ineffective or minimally effective in long-standing cases with fibrosis or damaged trabecular meshwork.
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- Amar Agarwal, MS, FRCS, FRCOphth, is director of Dr. Agarwal’s Eye Hospital and Eye Research Centre. Agarwal is the author of several books published by SLACK Incorporated, publisher of Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at 19 Cathedral Road, Chennai 600 086, India; email: dragarwal@vsnl.com; website: www.dragarwal.com.
- Priya Narang, MS, can be reached at Narang Eye Care & Laser Centre, Ahmedabad, India; email: narangpriya19@gmail.com.
Disclosures: The authors report no relevant financial disclosures.