Objective To test the effects of large amount of blood in the vitreous on electrophysiological examination. Methods The reductions of transmission of flash light through a serial dilution and depth of whole blood were measured.An experimental model of vitreous hemorrhage in rabbits was established by injecting 0.5ml autologous uncoagulated whole blood into the vitreous cavities after compression with an expanding perfluoropropane gas bubble.Pars plana vitrectomy was performed to clear the blood clots 2 weeks after blood injection.Ganzfeld and bright-flash electroretinography were performed through six-week observation period. Results Blood reduced remarkably the transmission of reduced remarkably the transmission of bright-flash light.Massive vitreous hemorrhage had a dense filtering effect and extinguished the Ganzfeld but not the bright-flash electrotetinogram.About 3.5log units higher of the intensities of bright- flash light than that of conventional method could stimulate the responses of ERG-B waves in blood injected eyes.Slow recovery of Ganzfeld ERG-b waves after vitrectomy were noted within 2 weeks (Plt;0.05),AND ERG-b wave reached at 80-90% of normal level during the third week. Conclusion The ERG-b waves,which become undetectable because of absorption of the dense opacities of the absorption of the dense opacities of the vitreous in eyes with a large amount of vitreous hemorrhage,can be recorded in bright-flash light conditions with nearly nearly normal amplitudes.This result indicates that functions of retina were not severely damaged by the large amount of vitreous hemorrhage. The injection of large amount of blood into vitreous cavities may cause a transient reduction of the amplitudes of ERG-b waves. (Chin J Ocul Fundus Dis,1998,14:104-107)
One hundred and eighty-nine cases of retinal detachment complicated with advanced proliferative vitreoretinopathy (grade C or D)were treated with scleral buckling or vitreous surgery,The reattachment rate was 63% ,ranging from 87.5% in grade C1 to 30.4% in grade D3.Retinas were reattached in 119,of which the postoperative visual acuity was counting finger or better in 95.8% and 20/200 or better in 26.9% in those cases,of grade C1 to C2 without proliferative vitreoretinopathy. The major causes of surgical failure were development of new or recurrent anterior PVR(51.4%),posterior epiretinal proliferation making pre-existing retinal breaks open and creation of new breaks (25.7%). Finally,we discussed the time of vitreoretinal surgery,methods of operation and the formation of anterior PVR. （Chin J Ocul Fundus Dis,1994,10:199-202）
ObjectiveTo 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.MethodsA 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.ResultsLens 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.ConclusionIn 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.
Proliferative diabetic retinopathy is a serious complication of diabetes in the eye that can lead to severe vision loss or even complete vision loss. In recent years, with the rapid development of surgical equipment and fundus examination technology, the indications for pars plana vitrectomy based surgical treatment have been expanded, surgical improvement and application, combined application of drugs, such as anti-vascular endothelial growth factor drugs, glucocorticoids, and surgical evaluation have made new progress. Surgical evaluation based on imaging can continuously monitor patients' eye conditions before, during and after surgery, and clinicians can choose different surgical plans and timing for different patients, which can help reduce patients' pain and achieve better visual outcomes.