Comparative evaluation of the safety of the lens and the ora serrata during vitrectomy with scleral incisions at 5.0 mm or 4.0 mm posterior to the limbus

Abstract

Objective To investigate the lens and ora serrata safety during 23G vitrectomy with sclera incisions at 5.0 mm or 4.0 mm posterior to the limbus. Methods A prospective case-controlled study was adopted. From April 2016 to January 2018, 290 consecutive primary 23G vitrectomy patients (300 eyes) with vitreoretinal disease in Department of Ophthalmology of Subei People’s Hospital Affiliated to Yangzhou University were enrolled in this study. Among them, 146 patients (150 eyes) received 23G pars plana vitrectomy (PPV) with scleral incisions at 5.0 mm posterior to the limbus (5.0 mm group), and 144 patients(150 eyes) at 4.0 mm (4.0 mm group). No statistically significant difference was found in age, axial length(t=−1.324, 0.867; P=0.186, 0.387) and in gender, right/left eyes, proportion of indications (χ2=1.366, 2.615, 10.195; P=0.242, 0.106, 0.070) between the two groups. The incidence rate of complications between the two groups were comparatively observed, such as lens injury, retinal tears close to the scleral incision, retinal hemorrhage, supra-choroidal expulsive hemorrhage and iatrogenic retinal detachment. Independent sample t test and χ2 test were performed for comparison between the two groups. Results Lens injury was observed in 4 eyes(2.67%) and 14 eyes (9.33%) respectively in the 5.0 mm and 4.0 mm group during surgery (χ2=5.910, P=0.015). Retinal tears close to the scleral incision sites were observed in 5 eyes (3.33%) and 6 eyes (4.00%) respectively in the 5.0 mm and 4.0 mm group during surgery (χ2=0.094, P=0.759). The mean time of removing the vitreous base was 6.17±2.76 min and 10.03±5.56 min respectively in the 5.0 mm and 4.0 mm group (t=7.599, P <0.01). No other surgical complications occurred in any group, such as retinal hemorrhage, supra-choroidal expulsive hemorrhage and iatrogenic retinal detachment, etc. Conclusion In primary 23G PPV, the safety of ora serrata with incisions at 5.0 mm posterior to limbus is similar to that at 4.0 mm, but the safety of lens and the efficiency of vitreous resection is higher with incisions at 5.0 mm. Key words: Vitrectomy; Lens, crystalline/injuries; Retinal perforations