Issa et al were significantly more patients in the 20 gauge group who required the use of scissors to perform delamination. There were also significantly more patients requiring gas tamponade in the 20 gauge group. All other variables assessed between the groups were nonsignificant. The number of eyes where retinal breaks were observed is shown in Table 2. There was a significant reduction in the incidence of sclerotomy-related breaks and lesions suspicious for breaks, as well as posterior breaks in the 23 gauge group as compared with the 20 gauge group. Two cases in the 20 gauge group had an entry site positioned for retinal dialysis and one case had a tear measuring one and a half clock hours in extent behind the entry site. There were no similar lesions in the 23 gauge group. Scleral buckling was not used in any patient. There was one patient in each group who experienced a retinal detachment postoperatively related in both cases to a posterior retinal break associated with recurrent traction. Postoperative follow-up was for a minimum of six months in all included eyes. Discussion The number of reported retinal breaks found during vit- rectomy for PDR has consistently been higher than during vitrectomy for other indications.3 Peripheral breaks have been described in diabetic vitrectomy, with rates ranging from 3% to 22%,1,2,4,9–12 depending on the complexity of the surgery, with approximately 40% of these related to the sclerotomy entry sites.3 Posterior breaks have been described in 10%–55% of cases and again vary according to the com- plexity of the case series.2,4,9–11 In our 20 gauge cases, we found peripheral retinal breaks in 14% of all eyes, of which 58% were sclerotomy site in location and 14% were posterior retinal breaks. Overall 18.8% of eyes in our 20 gauge group Table 2 number of retinal breaks in each group eyes with pre-existing retinal breaks eyes with posterior retinal breaks eyes with peripheral retinal breaks located away from sclerotomies eyes with peripheral sclerotomy related breaks Total number of eyes with definite peripheral breaks Total number of eyes with definite new breaks Abbreviation: TsV, transconjunctival vitrectomy. 112 submit your manuscript | www.dovepress.com Dovepress Dovepress had new retinal breaks observed during vitrectomy, similar to previous accounts. We used a tunneled incision 20 gauge technique. Previous case series reporting retinal breaks during 20 gauge diabetic vitrectomy have all used conventional straight incision 20 gauge surgery. Reporting of rates of retinal break formation with similar tunneled techniques has been limited.7,13,14 Furthermore, rates for diabetic vitrectomy have not been specifically reported, but these publications and our results suggest that the tunneled 20 gauge technique does not increase the rate of break formation compared with conventional 20 gauge surgery. The rate of retinal break formation during TSV surgery with narrow gauge instruments and cannulated scleroto- mies in diabetic vitrectomy has not been systematically described. Tan et al reported a higher rate of retinal break formation during 25 gauge vitrectomy surgery for macular hole and macular pucker relative to previous 20 gauge series, although there was no control group.5 However, other authors have found broadly similar rates between narrow gauge and 20 gauge surgery for the same conditions.15,16 In a uncontrolled case series, Farouk et al reported that 14.5% of 200 eyes operated on using 25 gauge TSV for PDR had retinal breaks observed, with the rate rising to 31.5% in those requiring dissection of membranes. Park et al reported that retinal breaks were observed in 8.6% of 35 eyes operated on for vitreous hemorrhage associated with PDR using 23 gauge TSV compared with 15.2% of 66 eyes operated on using 20 gauge surgery. In this latter series, the total difference was not significant and in both these series it is uncertain if the breaks were posterior or peripheral.17,18 We found a lower rate of retinal break formation for both posterior and sclerotomy- related retinal breaks in our TSV group compared with the 20 gauge control group 23 gauge TSV group 2 (2%) 12 (14%) 5 (6%) 6 (7%) suspicious lesions 11 (13%) total 7 (8%) 7 (8%) suspicious lesions 14 (16%) total 12 (14%) 16 (18.8%) (8 eyes had both posterior and peripheral breaks) 2 (2%) 3 (4%) 3 (4%) 5 (6%) suspicious lesions 8 (9%) total 2 (2%) 2 (2%) suspicious lesions 4 (5%) total 5 (6%) 6 (7%) (2 eyes had both posterior and peripheral breaks) Fisher’s exact test (P value) 1 0.03 0.72 0.63 0.17 0.02 0.123 0.0379 Clinical Ophthalmology 2011:5