Complications ConsultFrom OSN APAO

Single-pass four-throw pupilloplasty has utility in angle-closure glaucoma

Cases of plateau iris syndrome, Urrets-Zavalia syndrome and secondary angle closure can be treated with this technique.

Single-pass four-throw pupilloplasty, or SFT, is a new variant in the arena of existing techniques and procedures for performing pupilloplasty. Angle-closure glaucoma is characterized by narrowing and crowding of the anterior chamber angle as diagnosed on gonioscopy and anterior segment OCT examination, along with optic nerve changes and elevated IOP.

Laser peripheral iridotomy (LPI) forms the basis of initial therapy in cases of angle-closure glaucoma, but LPI fails to act in cases with plateau iris syndrome (Figure 1), Urrets-Zavalia syndrome and selected cases of secondary angle closure (Figure 2), which lead to the formation of peripheral anterior synechiae (PAS) due to prolonged contact of the peripheral iris tissue into the anterior chamber angle. Argon LPI is often performed to pull the iris from the periphery by causing contraction of the iris tissue induced by the laser shot. Argon LPI needs a laser machine and often needs to be redone due to the wearing-off effect over a period of time. In such cases, surgical pupilloplasty can act by causing the iris tissue to pull away from the periphery and prevent it from falling back into the angle. The mechanical pull induced on the iris due to pupilloplasty causes traction to the recently formed PAS and leads to its breakage, with opening of the angle structures to a greater extent.

SFT for angle-closure glaucoma
Figure 1. SFT for angle-closure glaucoma in plateau iris syndrome. A case of plateau iris with failed LPI and cataract extraction with raised IOP (a). A 10-0 suture attached to the long arm needle is passed through the corneal tissue, engaging the proximal iris tissue. The tip of the needle is docked into the barrel of 26-gauge needle introduced from the opposite end through the paracentesis incision. The 10-0 needle is withdrawn from the anterior chamber (b). A loop is withdrawn into the anterior chamber with end-opening forceps (c). The loop is pulled outside the anterior chamber, and the suture end is passed four times through the loop (d). Both of the suture loops are pulled, and this slides the knot into the anterior chamber. The suture ends are cut with micro-forceps (e). Pupilloplasty is performed with the vitrectomy probe to ensure adequate pupil size in the visual axis (f).

Source: Priya Narang, MS, and Amar Agarwal, MS, FRCS, FRCOphth

SFT for secondary angle-closure glaucoma
Figure 2. SFT for secondary angle closure in an eye with the presence of silicone oil. Preoperative image of an eye filled with silicone oil and presence of secondary angle-closure glaucoma (a). Preoperative anterior segment OCT demonstrating angle-closure glaucoma (b). Postoperative image demonstrating six-point traction after an SFT procedure with removal of silicone oil (c). Postoperative anterior segment OCT demonstrating opening of the anterior chamber angles (d).
Anterior segment OCT
Figure 3. Anterior segment OCT. Preoperative anterior segment OCT image demonstrating narrow angles (a). Postoperative anterior segment OCT image demonstrating wide angles (b).

Surgical procedure

A 360° pupillary stretching at every clock hour is performed with end-opening forceps, which involves pulling the iris tissue toward the center of the visual axis. This helps break the PAS and helps gauge the amount of iris tissue that is available for pupil reconstruction, especially in cases with Urrets-Zavalia syndrome in which there is persistent pupillary dilation with the fall back of the iris tissue into the peripheral angle. In cases with 360° synechiae, often six-point traction is needed, which involves performing the SFT pupilloplasty three times so as to pull the entire tissue from the periphery.

In our short study of five cases, a statistically significant reduction in the degree and area of PAS was noted, which was assessed by gonioscopy and angle digital photography analysis (ImageJ software). The measurement and quantification of the degree of PAS were determined by screening all axes of the angles using anterior segment OCT (Figure 3). Postoperatively, there was a significant deepening of the anterior chamber, and a significant clinical opening of the angle was detected on gonioscopy from the preoperative to postoperative period. There was a considerable decrease in IOP and improvement in visual acuity in all of the cases in the postoperative period. A Goldmann three-mirror lens was used to perform gonioscopy, and a modified Shaffer’s grade was assigned for each quadrant. In a case of Urrets-Zavalia syndrome, cut-through of the iris tissue during passage of the needle was observed due to associated iris atrophic patches. In such cases, extreme care should be taken and the needle should be passed carefully, avoiding all areas of iris thinning to prevent any further chaffing of the iris tissue.

There are certain limitations with this procedure. First, it cannot be performed in phakic eyes and hence needs a cataract extraction to be done simultaneously. Performing cataract surgery in cases with angle-closure glaucoma is a standard treatment adopted by various surgeons. Hence, the issue of lens presence can be overruled, taking into consideration the potential advantages that are offered following a cataract surgery in cases with angle-closure glaucoma. Second, because it is an intraocular procedure, it carries the usual surgical risks and may be associated with induced inflammation in an already inflamed eye.

The advantage of performing SFT is that the pupil has been documented to dilate after instillation of mydriatics, which was quantified on anterior segment OCT analysis. After mydriatic instillation, a clinically significant increase in pupillary size occurred, with higher mydriasis in the vertical axis as compared with the horizontal axis. The induced mydriasis was significant, and it is theorized to aid in fundus visualization and monitoring of glaucoma progression.

Disclosures: Agarwal and Narang report no relevant financial disclosures.

Single-pass four-throw pupilloplasty, or SFT, is a new variant in the arena of existing techniques and procedures for performing pupilloplasty. Angle-closure glaucoma is characterized by narrowing and crowding of the anterior chamber angle as diagnosed on gonioscopy and anterior segment OCT examination, along with optic nerve changes and elevated IOP.

Laser peripheral iridotomy (LPI) forms the basis of initial therapy in cases of angle-closure glaucoma, but LPI fails to act in cases with plateau iris syndrome (Figure 1), Urrets-Zavalia syndrome and selected cases of secondary angle closure (Figure 2), which lead to the formation of peripheral anterior synechiae (PAS) due to prolonged contact of the peripheral iris tissue into the anterior chamber angle. Argon LPI is often performed to pull the iris from the periphery by causing contraction of the iris tissue induced by the laser shot. Argon LPI needs a laser machine and often needs to be redone due to the wearing-off effect over a period of time. In such cases, surgical pupilloplasty can act by causing the iris tissue to pull away from the periphery and prevent it from falling back into the angle. The mechanical pull induced on the iris due to pupilloplasty causes traction to the recently formed PAS and leads to its breakage, with opening of the angle structures to a greater extent.

SFT for angle-closure glaucoma
Figure 1. SFT for angle-closure glaucoma in plateau iris syndrome. A case of plateau iris with failed LPI and cataract extraction with raised IOP (a). A 10-0 suture attached to the long arm needle is passed through the corneal tissue, engaging the proximal iris tissue. The tip of the needle is docked into the barrel of 26-gauge needle introduced from the opposite end through the paracentesis incision. The 10-0 needle is withdrawn from the anterior chamber (b). A loop is withdrawn into the anterior chamber with end-opening forceps (c). The loop is pulled outside the anterior chamber, and the suture end is passed four times through the loop (d). Both of the suture loops are pulled, and this slides the knot into the anterior chamber. The suture ends are cut with micro-forceps (e). Pupilloplasty is performed with the vitrectomy probe to ensure adequate pupil size in the visual axis (f).

Source: Priya Narang, MS, and Amar Agarwal, MS, FRCS, FRCOphth

SFT for secondary angle-closure glaucoma
Figure 2. SFT for secondary angle closure in an eye with the presence of silicone oil. Preoperative image of an eye filled with silicone oil and presence of secondary angle-closure glaucoma (a). Preoperative anterior segment OCT demonstrating angle-closure glaucoma (b). Postoperative image demonstrating six-point traction after an SFT procedure with removal of silicone oil (c). Postoperative anterior segment OCT demonstrating opening of the anterior chamber angles (d).
Anterior segment OCT
Figure 3. Anterior segment OCT. Preoperative anterior segment OCT image demonstrating narrow angles (a). Postoperative anterior segment OCT image demonstrating wide angles (b).

Surgical procedure

A 360° pupillary stretching at every clock hour is performed with end-opening forceps, which involves pulling the iris tissue toward the center of the visual axis. This helps break the PAS and helps gauge the amount of iris tissue that is available for pupil reconstruction, especially in cases with Urrets-Zavalia syndrome in which there is persistent pupillary dilation with the fall back of the iris tissue into the peripheral angle. In cases with 360° synechiae, often six-point traction is needed, which involves performing the SFT pupilloplasty three times so as to pull the entire tissue from the periphery.

In our short study of five cases, a statistically significant reduction in the degree and area of PAS was noted, which was assessed by gonioscopy and angle digital photography analysis (ImageJ software). The measurement and quantification of the degree of PAS were determined by screening all axes of the angles using anterior segment OCT (Figure 3). Postoperatively, there was a significant deepening of the anterior chamber, and a significant clinical opening of the angle was detected on gonioscopy from the preoperative to postoperative period. There was a considerable decrease in IOP and improvement in visual acuity in all of the cases in the postoperative period. A Goldmann three-mirror lens was used to perform gonioscopy, and a modified Shaffer’s grade was assigned for each quadrant. In a case of Urrets-Zavalia syndrome, cut-through of the iris tissue during passage of the needle was observed due to associated iris atrophic patches. In such cases, extreme care should be taken and the needle should be passed carefully, avoiding all areas of iris thinning to prevent any further chaffing of the iris tissue.

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There are certain limitations with this procedure. First, it cannot be performed in phakic eyes and hence needs a cataract extraction to be done simultaneously. Performing cataract surgery in cases with angle-closure glaucoma is a standard treatment adopted by various surgeons. Hence, the issue of lens presence can be overruled, taking into consideration the potential advantages that are offered following a cataract surgery in cases with angle-closure glaucoma. Second, because it is an intraocular procedure, it carries the usual surgical risks and may be associated with induced inflammation in an already inflamed eye.

The advantage of performing SFT is that the pupil has been documented to dilate after instillation of mydriatics, which was quantified on anterior segment OCT analysis. After mydriatic instillation, a clinically significant increase in pupillary size occurred, with higher mydriasis in the vertical axis as compared with the horizontal axis. The induced mydriasis was significant, and it is theorized to aid in fundus visualization and monitoring of glaucoma progression.

Disclosures: Agarwal and Narang report no relevant financial disclosures.