ABSTRACT
AIM: To investigate hemodynamic alterations of retrobulbar vessels in proliferative diabetic retinopathy ( PDR) patients with anterior segment neovascularization, before and 3mo after vitrectomy combined with panretinal photocoagulation and to explore the clinical significance. ●METHODS: Color Doppler flow imaging ( CDFl ) was used for measurement of blood flow velocities and resistive indexes ( Rl ) of the ophthalmic artery ( OA ) , short posterior ciliary arteries ( sPCA ) and central retinal artery ( CRA ) in 21 eyes of 21 PDR patients with anterior segment neovascularization. CDFl parameters were obtained before and 3mo after vitrectomy combined with panretinal photocoagulation ( PRP) . ● RESULTS: Peak systolic velocity ( PSV ) and end diastolic velocity ( EVD ) of CRA were significantly increased after surgeries, Rl were decreased significantly (P0. 05). ●CONCLUSION: Vitrectomy combined with panretinal photocoagulation might increase the velocity of CRA, decrease Rl and improve ocular blood supply postoperatively. lt may delay or prevent the process of neovascular glaucoma.
ABSTRACT
Background A main cause of visual impairment in proliferative diabetic retinopathy (PDR) is vitreous hemorrhage and retinal detachment due to contraction of fibrovascular membrane.To explore the pathogenic mechanism of fibrovascular membrane is a new target for the prevention and management of PDR.Objective This study was to determine the change in expression of vascular endothelial growth factor (VEGF),connective tissue growth factor(CTGF) and pigment epithelium derived factor(PEDF) in the proliferative membranes of patients with PDR after intravitreal injection of avastin,an anti-VEGF agent.Methods This study was approved by the Medical Ethic Committee of Tianjin Medical College,and written informed consent was obtained from each patient before enrollment.A prospective randomized-controlled study was designed.Twenty-six eyes of 24 patients with PDR scheduled for surgery were enrolled from January to June,2008 in Tianjin Medical College Eye Hospital.The patients were randomized into the simple vitrectomy group and avastin injection combined with vitrectomy group,with matched gender,age and disease duration.1.25 mg (0.05 ml) of avastin was intravitreally injected prior to surgery,and vitrectomy was performed 10 days after injection in the avastin injection combined with vitrectomy group,and only vitrectomy was given in the simple vitrectomy group.Preretinal membrane was collected during the surgery.Expression of VEGF,CTGF and PEDF in the preretinal membranes was assayed by immunochemistry.Results VEGF,CTGF and PEDF were expressed in the cytoplasm.The rate of VEGF expression in the preretinal membranes was 30.77％ in the avastin injection combined with vitrectomy group,showing a significant reduction in comparison with the simple vitrectomy group(100.00％)(U =4.000,P＜0.01).The rate of expression CTGF was remarkable elevated in the avastin injection combined with vitrectomy group compared with the simple vitrectomy group (92.31％ vs.62.54％)(U=7.500,P=0.048).However,no significant difference was found in the expression rate of PEDF between the two groups(100.00％ vs.92.31％) (U =65.500,P =0.299).Conclusions The results suggest that intravitreal injection of anti-VEGF drugs resulted in the decrease of VEGF expression and increased CTGF expression in proliferative membranes from patients with PDR.
ABSTRACT
BackgroundThe research of corneal thickness after pars plana vitrectomy in DM patient plays an important role not only theoretically but clinically.Objective Present study was to evaluate the change in corneal thickness after pars plana vitrectomy.Methods A prospective coherent study was designed.Seventy-five eyes of 70 consecutive diabetic retinopathy(DR) patients were collected in Tianjin Medical University Eye Center.Pentacam was used to assess the central and periphery corneal thickness by the same investigator preoperatively and 7 days,1 and 3 months postoperatively,respectively.The thickness values from five corneal zone were obtained,including cornea vertex,the thinnest point of the cornea,periphery cornea near the scleral incision of 4 mm away to vertex of cornea on vertical and 240°,120°,60° meridian ( right eye) or 300°,120°,60° meidian ( left eye ).These results were compared and analyzed with ANOVA of repeated measurement data.Subgroup analysis was performed to evaluate the influence of different corneal positions,the use of conventional 20g or 23g transconjunctival sutureless vitrectomy(TSV) groups,surgery duration,gas or fluid endotamponde on corneal thickness.This study was approved by Ethic Committee of this hospital.Written informed consent was obtained from the subjects before any relative medical procedure.Results The mean corneal thickness was ( 639.9 ± 103.1 ),( 689.5 ± 119.3 ),( 666.5 ±113.7),( 650.8 ± 108.6 ) μm before operation,postperative 7 days,1 and 3 months respectively.As covariates appearing in the model,the corneal thickness change rates were revised as the parameters as following: diabeitc duration =13.0 and age =57.2.The revised corneal thickness was significant different among various time points( F=210.928,P=0.000) and different corneal zones(F=24.843,P=0.000) with the size order in turn P4＞P3＞P1＞P2＞P5.The corneal thickness change rates were less in 23g TSV group compared with conventional 20-g group (F =53.843,P =0.000) and BSS tamponade group compared with gas tamponade group ( F =5.288,P =0.022).But no significant difference was found in the revised corneal thickness among surgery duration ＜ 1 hour group,1-2 hour group and ＞2 hour group( F=1.233,P =0.293).ConclusionsVitrectomy is a safe procedure on the ground of cornea,but TSV and fluid endotamponade appear to be more beneficial to the protection of cornea.Pentacam could offer the reliable data in not only central cornea but also periphery cornea.