Scleral Incisions Evaluated By with Anterior Segment Optical Coherence Tomography

Abstract

The article by Taban and associates investigated the wound morphology in 23-gauge sutureless oblique sclerotomies for cannula microincision 3-port pars plana vitrectomies with the Visante anterior segment optical coherence tomography (OCT).1Taban M. Sharma S. Ventura A.A. Kaiser P.K. Evaluation of wound closure in oblique 23-gauge sutureless sclerotomies with Visante optical coherence tomography.Am J Ophthalmol. 2009; 147: 101-107Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar The sclera was penetrated with a 23-gauge trocar cannula microvitrectomy system as tangentially as possible parallel to the limbus. Once the outer half was penetrated, the angle of the trocar was changed to 90 degrees to insert into the globe. All incisions were imaged in 14 patients with the Visante OCT device with an axial resolution of 18 μm and transverse resolution of 60 μm. The gross clinical examination revealed no evidence of leakage. OCT demonstrated closed wounds in all eyes on postoperative days 1 and 8. The authors concluded that oblique incisions for microincision sutureless vitrectomy may prevent wound leakage and decrease the risk of endophthalmitis. We congratulate the authors on their study. Recently we also determined the reflux and anatomic structure of sclerotomies by the Visante OCT in 18 patients undergoing intravitreal injections by oblique or straight scleral incisions.2Rodrigues E.B. Meyer C.H. Grumann Jr, A. Shiroma H. Aguni J.S. Farah M.E. Tunneled scleral incision to prevent vitreal reflux after intravitreal injection.Am J Ophthalmol. 2007; 143: 1035-1037Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar We used a similar technique by placing a 30-gauge needle with the bevel up in a 30-degree angle for approximately 1.5 mm into the outer half of the sclera. The needle was now directed towards the center of the globe to penetrate the inner sclera into the midvitreous. All our eyes with an oblique tunneled injection had significantly less reflux compared to straight tangential injections. The injected volume as well as the length and direction of the tunneled scleral incision may influence the closure of the scleral wound. Both studies suggested that oblique incisions in a beveled or tunneled fashion provide better wound apposition and stability compared to straight incisions. Oblique scleral incisions promoted also for “transconjunctival 20-gauge vitrectomies” a safe approach,3Aguni J.S. Meyer C.H. Rodrigues E.B. Transconjunctival 20-gauge vitrectomy: a pilot study.Ophthalmologica. 2008; 223: 12-16Crossref PubMed Scopus (5) Google Scholar while straight or tangential injections may remain open, inducing leakage and ocular hypotony even with 30-gauge needles.4Rodrigues E.B. Meyer C.H. Schmidt J.C. Hoerle S. Kroll P. Unsealed sclerotomy after intravitreal injection with a 30-gauge needle.Retina. 2004; 24: 810-812Crossref PubMed Scopus (13) Google Scholar Oblique or angled incisions are believed to decrease wound leakage by having an internal lip that presses against the outer lip through the elevated intraocular pressure, helping to close the wound. Anterior segment OCT is a valuable tool to visualize the surgical wound during the postoperative period.