Iris and knot configuration after Single Pass Four Throw (SFT) pupilloplasty as imaged by the spectral-domain optical coherence tomography

Abstract

Purpose: To analyze the morphological changes in the iris-knot complex configuration using spectral-domain optical coherence tomography (SD-OCT) following the single pass four throw (SFT) pupilloplasty. Methods: In this retrospective case series, eyes with SFT pupilloplasty were examined by SD-OCT (Optovue). Iris morphology compared to the normal iris, presence of specific patterns (single hump, double humps, peaks and valleys, tethering), prolene suture, knot complex (length and orientation), and intraocular lens (IOL) vault were evaluated. Results: Overall, 41 knots of 26 patients with a mean time duration of 3.1 ± 2 months from surgery were analyzed. Iris configurations seen were single hump ( n = 28, 63.8%), double humps ( n = 7, 17%), loop ( n = 2, 4.8%), flat ( n = 3, 7.3%), and mulberry ( n = 1, 2.4%). The mean length and the height of the knot complex was 784.1 ± 433.7 μm and 317.7 ± 110.4 μm, respectively. Knot positions were at 3 clock hours in 9 eyes (21.9%), 9 in 8 eyes (19.5%), and others in 24 eyes (58.5%). Cut end of the prolene suture was detectable in 26 eyes (63.4%) as hyper-reflective line, and the mean cut length was 465.8 ± 321.1 μm. The suture was predominantly vertically oriented (80.6%) to the iris with a mean distance of 3.6 ± 0.3 mm (2.6–4 mm) away from corneal endothelium. The mean distance from the knot complex and the IOL was 289.2 ± 146 μm and the mean anterior chamber depth was 4.1 ± 0.1 mm. Conclusion: A significant change in iris configuration was noted after SFT pupilloplasty, and vertically oriented retained prolene suture was predominant with good endothelial vault.

Reverse four-throw technique for pupilloplasty

“…Although the SFT knot lies flat to the iris surface, AS-OCT analysis of the knot for SFT pupilloplasty demonstrated a mean length of the suture tail to be 465.8 ± 321.1 μm that was positioned vertically in the AC in 80% of the eyes. 9 AS-OCT analysis for RFT depicted no suture extrusion into the anterior chamber with smooth iris configuration (Figure 4(a) and (b)). However, there is a possibility of pigment liberation due to the presence of suture knots on the posterior surface of the iris, although the authors did not observe it in any case till the last follow-up.…”

“…In almost all the techniques of pupilloplasty, suture knots are formed on the anterior surface of the iris that can potentially pose a hazard during EK procedure due to the possibility of mechanical damage to the endothelial graft. 9 We present reverse four-throw (RFT) pupilloplasty that involves a single needle-pass through the AC and helps achieve a posteriorly directed suture knot.…”

Comparison of cosmesis, mydriasis, fundus visibility, and anterior chamber depth following single-pass four-throw pupilloplasty in congenital and traumatic iris defects

“…Pupil is an aperture in the iris of the eye through which light enters into the eye. [ 1 ] The pupil shape may be distorted due to congenital or acquired causes such as coloboma, traumatic or surgical iris tear or iridodialysis, following iris mass excision, acorea, and polycorea. [ 2 ] The diameter of the pupil may increase due to traumatic or surgical atonia.…”