Issa et al Small incision transconjunctival vitrectomy (TSV) with cannulated sclerotomies has become increasingly popular, with a number of proposed advantages, including reduced postoperative discomfort and more rapid visual rehabilitation. However, concerns have been raised with regard to the occurrence of postoperative hypotony and endophthalmitis, and it has also been questioned whether narrow gauge surgery is associated with an increased rate of peripheral retinal break formation in macular surgery and a lower success rate in retinal reattachment surgery compared with 20 gauge surgery.5,6 These concerns are particularly relevant to vitreous surgery for PDR where retinal break formation is more common. Furthermore, the angulated scissors commonly used in conventional 20 gauge vitrectomy surgery cannot be used during narrow gauge surgery, and a change in delamination technique is required to achieve membrane removal. With any new technique it is important to evaluate any potential adverse effects. Therefore, the aim of this study was to evaluate the rate and nature of retinal breaks found during a consecutive series of patients treated with 23 gauge TSV surgery with PDR, and compare them with a similar series of patients treated by the same surgeon with 20 gauge surgery. Methods A consecutive series of patients who had undergone primary pars plana vitrectomy for the complications of proliferative diabetic retinopathy by one surgeon at Sunderland Eye Infirmary from July 2003 to January 2010 were prospectively identified. The cases were divided into two groups, ie, a control group treated from July 2003 to March 2006 where only conventional 20 gauge vitrectomy surgery was carried out, and a second group from July 2007 to January 2010 where only 23 gauge TSV surgery was carried out. Patients who had vitrectomy surgery between April 2006 and June 2007 were excluded because at that time the surgeon was using a mixture of 20 gauge, 23 gauge, and 25 gauge surgery. Twenty gauge surgeries were carried out using self-sealing 20 gauge tunnels as previously described for the Alcon Accurus system and Innovit cutter.7 The Innovit cutter has a maximum cut rate of 1800 cuts per minute and has a 0.38 mm tip to port distance. TSV surgery was carried out using the Alcon Accurus and Constellation 23 gauge systems. The Accurus and Constellations cutters have a maximum cut rate of 2500 and 5000 cuts per minute, respectively, and their tip to port distance is 0.23 mm. A wide-angle noncontact indirect viewing system, with an inbuilt image inverter, was used in all cases. 110 submit your manuscript | www.dovepress.com Dovepress Dovepress After core vitrectomy, delamination and removal of all posterior hyaloid face and fibrovascular membrane was carried out. This was carried out primarily with the vitreous cutter alone and intravitreal scissors only if necessary. Twenty gauge horizontal or vertical scissors were used in the 20 gauge group whilst 23 gauge curved horizontal scissors (Grieshaber DSP) were used in the 23 gauge group. In none of the 23 gauge cases was a sclerotomy opened up for 20 gauge instruments. Careful inspection to detect the presence of vitreous schisis was made, and staining of residual vitreous gel using diluted triamcinolone was used routinely in all cases. Any vitreoschisis detected was peeled using the vitreous cutter and forceps as necessary. Hemostasis was obtained using raised infusion pressure and endodiathermy as needed. The extent of fibrovascular proliferation and vitreoretinal adherence present and requiring peeling/delamination was graded according to disc areas and also classified as by Yorston et al.2 Peripheral vitreous was removed, especially around the inner sclerotomy wounds, with deep scleral indentation. Indirect or endolaser peripheral retinal laser photoco- agulation was carried out to the peripheral retina up to the ora serrata in all eyes. A meticulous internal search using endoviewing and indentation with a noncontact wide field viewing system was performed. Retinal breaks were treated with argon laser retinopexy or cryotherapy. Sulfur hexafluo- ride gas or air were used as postoperative tamponade where needed. Preoperative antivascular endothelial growth factor therapy was not used in any patient. Retinal breaks observed during vitrectomy were divided into a number of categories by their appearance, causation, and position, and carefully recorded: • Peripheral sclerotomy-related breaks. Breaks were classif ied as such if they were retinal dialyses or posterior vitreous base tears within one clock hour of the sclerotomy sites. Retinal breaks in this category were further divided into definite breaks and suspicious lesions. The definition of a definite break included a clearly elevated retinal flap or distinct retinal edge con- firmed during retinopexy. Lesions suspicious for breaks were classified if a distinct flap or edge could not be observed but there was some degree of retinal elevation or tufting, especially if associated with localized retinal hemorrhage. • Other peripheral breaks mainly related to surgically induced extension or creation of a posterior vitreous detachment (PVD). Again these were categorized as definite or suspicious. Clinical Ophthalmology 2011:5