Laser Photo-Cauterization for the Management of Exposed Polypropylene Scleral Fixation Sutures

In case of insufficient capsular support, scleral-fixated intraocular lenses (SFIOLs) remain one of the most popular options of secondary IOL implantation. Polypropylene sutures (10-0 or 9-0) are commonly employed for this purpose.1 Despite many years of experience with polypropylene, suture erosion and exposure remains a notorious problem. Over time, tips of the suture may erode through the conjunctiva and poke at the ocular surface, causing significant discomfort to the patient (Figs. 1A, C). Exposed sutures are also a potential source of infection allowing pathogens to track into the eye. Several approaches have been adopted to mitigate and treat this complication. These include knot burial, long suture ends, scleral flaps, scleral patch graft, corneal graft, and even fascia lata or dura mater grafts.2,3 Another method describes the use of a cautery to coagulate the ends of the exposed polypropylene suture.4FIGURE 1: Slitlamp photographs of 2 patients who presented with complaints of foreign body sensation after suture-assisted scleral fixation of intraocular lenses. Both patients had tips of polypropylene suture that had eroded through the conjunctival surface (A, C; Red Arrows). Images taken after laser photo-cauterization show a blunt suture tip that has either retracted or sits flush with the conjunctival surface (B, D; Black Arrows).The SFIOL technique we use is similar to the one used by Sindal et al.5 Polypropylene sutures are passed through the eyelets of a single-piece rigid IOL (SC6530; Aurolab; India, similar to CZ70BD lens; Alcon) and exteriorized by railroading on a 26G needle. The IOL is centered and knots are tied externally within a scleral groove or flap fashioned earlier. The groove and knot is then covered by the closure of the conjunctival peritomy over it. We faced the complication of suture tip exposure in these patients and sought a simpler, nonsurgical management strategy. The Yamane technique has shown that applying heat on polymethyl methacrylate or polyvinylidene fluoride haptics leads to the formation of a round-bodied coagulum.6 Use of green laser photocoagulation also achieves the same effect.7 On the basis of the same principle, we attempted laser photocoagulation of polypropylene suture tips. Two eyes of 2 SFIOL patients were satisfactorily treated using this technique. Under topical anesthesia, the suture ends were treated with yellow laser (PASCAL 577 nm, Topcon Medical Laser Systems, Santa Clara, CA). A maximum of 4 laser shots of size 100 µm (100 mW for 100 ms) were applied to each tip of the exposed suture ends. This resulted in immediate blunting and retraction of suture end below the conjunctival surface (Fig. 1B, D). We used yellow laser (due to ease of availability at our center) which has an absorption spectrum slightly different from green laser. There was no procedure-related discomfort or postprocedural change in refractive error. The sutures remained buried till the last follow-up of the patients, 6 months from the procedure. Polypropylene sutures are used for many indications, such as iridodialysis repair, fixing capsular tension segments or even prosthetic iris devices. We concluded that our technique is a novel and inexpensive method to treat exposed polypropylene sutures related to any scleral fixation procedure. However, this technique may not be suitable when entire suture knots are exposed. Potentially, it could also be used to treat exposure in double-flanged scleral-fixation technique.