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SFT pupilloplasty helps open angles in silicone oil-induced glaucoma
This method involves passing the suture needle through the anterior chamber only once, thus leading to less inflammation.
Secondary angle closure due to any mechanism compromises the normal aqueous outflow route and results in secondary elevation of IOP. Left uncorrected, over time this can cause optic nerve damage and possible permanent vision loss. When medical avenues are ineffective in opening the angle, surgical intervention to either open the closed angle or provide an alternate route of aqueous egress is essential to prevent potential vision loss.
Silicone oil, while an essential part of certain posterior segment surgical procedures, can have secondary unwanted effects on the anterior segment of the eye. One such deleterious effect can be secondary angle closure and elevated IOP.
In this column, Drs. Agarwal and Narang describe their surgical technique of pupilloplasty to correct secondary angle closure from intraocular silicone oil.
Thomas John, MD
OSN Surgical Maneuvers Editor
Source: Amar Agarwal, MS, FRCS, FRCOphth, and Priya Narang, MS
Silicone oil is the most common adjunct used in posterior segment surgeries involving retinal detachment. Although the benefits of a silicone oil tamponade are indisputable, often it leads to various complications in the postoperative period. One such commonly reported complication is the development of secondary glaucoma. This complication is often associated with placement of scleral buckles and an eventual rotation of the ciliary body that culminates in angle blockage and raised IOP. Many times, silicone oil also migrates into the anterior chamber (Figure 1) and poses a mechanical obstruction to the aqueous drainage from the trabecular meshwork. It may also lead to pupillary block and incite an inflammatory reaction in the eye that leads to formation of peripheral anterior synechiae (PAS) and an eventual trabecular meshwork blockage.
In cases with mechanical blockage due to iris tissue, surgical pupilloplasty has been demonstrated to pull the peripheral iris tissue and open the anterior chamber angles. Taking this fact into consideration, surgical pupilloplasty with single-pass four-throw (SFT) technique was performed in cases with silicone oil-induced glaucoma.
Technique
Silicone oil removal should be considered in these cases (Figure 2), and pupillary stretching with end-opening forceps should be performed (Figure 3). This helps to break the newly formed PAS and also helps to judge the amount of flexibility of the iris tissue and the amount of iris tissue that can be involved into the needle. Essentially, the technique adopted is SFT pupilloplasty with consideration taken to make a pass from the iris tissue that involves the PAS (Figures 4 and 5). The authors have developed a nomogram for performing pupilloplasty depending upon the degree and extent of the presence of PAS as detected on gonioscopy. For PAS more than 270°, a six-point traction is advocated, which involves making passes with the SFT procedure three times, and for cases with less than 270° of PAS, a four-point traction is advocated, which involves making two passes with SFT. Often the iris tissue is atrophied due to constantly raised IOP. Under such circumstances, the surgeon should avoid making a pass in the atrophied iris as there is a high chance of the suture getting cut through. The adjunct healthy iris tissue should be involved into the suture. The openings of the angle structures have been demonstrated on intraoperative gonioscopy (Figure 6).
Other considerations
Preoperative evaluation of these patients should include a detailed charting of gonioscopic findings that clearly delineates the extent of PAS present in the anterior chamber angle. Anterior segment OCT can be a useful adjunct to this as it can help evaluate patients in the postoperative period at eventually all follow-ups (Figures 7 and 8).
Before the patient is scheduled for surgery, preoperative control of IOP should be undertaken with topical medication or systemic route as indicated. We recommend performing the SFT procedure under fluid infusion rather than any ophthalmic viscosurgical device as any OVD that is inadvertently left behind in the eye can lead to raised IOP in the postoperative period. Intraoperative gonioscopy, when performed, helps to reconfirm the breakage of PAS and anterior chamber angle opening intraoperatively.
Although surgical pupilloplasty can be performed with any other technique, we employed the SFT method as 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 iris tissue that is already inflamed.
In a state in which conventional trabeculectomy fails quite often and repeated procedures have to be undertaken without a satisfactory result, here we have a combined procedure that fixes the causative problem of the closed angles and achieves normalization of pressures via the natural process of aqueous drainage. However, it is essential to state that surgical pupilloplasty would be rendered ineffective in cases with fibrosed or damaged trabecular meshwork due to chronic insult of trabecular meshwork passage.
- References:
- Narang P, et al. Eur J Ophthalmol. 2017;doi:10.5301/ejo.5000922.
- Narang P, et al. Eur J Ophthalmol. 2018;doi:10.1177/1120672117747038.
- Narang P, et al. Eur J Ophthalmol. 2018;doi:10.1177/1120672118780809.
- Narang P, et al. Single pass four-throw pupilloplasty (SFT) for angle closure glaucoma. Indian J Ophthalmol. In press.
- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, can be reached at Dr. Agarwal’s Eye Hospital and Eye Research Centre, 19 Cathedral Road, Chennai 600 086, India; email: aehl19c@gmail.com.
- Priya Narang, MS, can be reached at Narang Eye Care & Laser Centre, Ahmedabad, India; email: narangpriya19@gmail.com.
- Edited by Thomas “TJ” John, MD, a clinical associate professor at Loyola University at Chicago, and in private practice in Oak Brook, Tinley Park and Oak Lawn, Illinois. He can be reached at email: tjcornea@gmail.com.
Disclosures: Agarwal, Narang and John report no relevant financial disclosures.