| Diabetes is a group of metabolic diseases characterized by chronic elevated blood glucose levels and can cause metabolic disorder of multiple systems and organs. Diabetic retinopathy is one of the common and serious diabetic microvascular complications and is also one of the major causes of bindness . According to the estimation of World Health Organization (WHO), there are currently more than 150 million diabetics and the number will double by 2025; there exist 30 million diabetics in our country and we are inferior to India and the United States ranking second in the world.With the keeping increasing of diabetic patients,blindness due to diabetic retinopathy is increasing year by year.He Shouzhi found that the prevalence of DR is 16.9% during the workers'medical examination in Bejing Shougang Corporation from 1992 to 1994; the epidemiological survey of diabetes carried out by department of ophthalmology of Bejing Tongren Hospital between 1994 and 1995 showed that the prevalence of DR is 9.84%;Zhang Chunyuan who investigated 380 inpatients with diabetes in Xining,Qinghai Province between 1998 and 2001 found that the prevalence of DR is 67.89% and the prevalence of PDR is 17.82%.Diabetic retinopathy is closely related to the duration of diabetes.The investigations of wisconsin epidemiological study of diabetic retinopathy(WESDR) in 1984 revealed that the prevalence of DR is 28.8% and the prevalence of PDR is 2% with the duration of diabetes less than 5 years; the prevalence of DR is 77.8% and the prevalence of PDR is 15.5% with the duration of diabetes more than 15 years.The ocular fundus manifestations of diabetic retinopathy include microaneurysm,ecchymosis, hardexudate,cotton-wool spot,retinal vasculopathy,maculopathy,vitreous and optic neuropathy,et al. Proliferative diabetic retinopathy characterized by the formation of neovessels and fibrous tissue is the terminal stage of diabetic retinopathy and often combines vitreous hemorrhage, tractional and or rhegmatogenous retinal detachment, neovascular glaucoma which lead to serious decline or loss of vision. In the seventies of the 20th century ,Machemer invented vitreous infusion suction cutter which created a new era of vitrectomy with the removal of vitreous in the closed state of eye.In recent years vitrectomy has been widely used in complicated retinal detachment, severe ocular trauma, vitreous hemorrhage,endophthalmitis, macular disease,proliferative vitreoreti-nopathy,proliferative diabetic retinopathy and other complicated vitreoretinopathy .Vitrectomy which can remove the vitreous hemorrhage,relieve the traction on the retina caused by the proliferative membrane , restore the normal anatomy of the retina and maintain the integrity of the eyeball greatly reduces the blindness rate,therefore vitrectomy is the only effective method to the proliferative diabetic retinopathy.Accordingly it is very necessary to understand the impact of various factors on the postoperative visual acuity improvement.When vitrectomy is performed in early time ,the retina is thick and flexible and the fibrovascular membranes adhere to the retina relatively loose so that it is easy to peel and sheer the fibrovascular membranes,therefor the postoperative complicatinos are reduced and it is conducive to the restoration of visual function.During the vitrectomy, clear removal of vitreous around the above sclerotic puncture ports to avoid forming ora serrata mutilation caused by intraocular microinstruments'repeated access to eyeball bringing out peripheral vitreous,extensive removal of the peripheral and post-capsular vitreous,gently peeling the fibrovascular membranes to avoid over-stretch, peeling the fibrovascular membranes as far as possible,properly dealing with the stump of fibrovascular membranes,and reasonably selecting vitreous substitutes can reduce postoperative complications and get a better visual prognosis.In short, during the clinical work we should closely observe the ocular fundus and when diabetic retinopathy develop into proliferative diabetic retinopathy we should determine the stage of diabetic retinopathy, master surgical indications and select reasonable time of operation in order to obtain a better visual prognosis.Objective: To evaluate the surgical effect of vitrectomy and different factors on the prognosis of proliferative diabetic retinopathy.Methods: The clinical datum of sixty-one eyes of 50 patients'who were cured by the same medical group in Department of ocular fundus disease in our hospital were studied from Oct,2007 to Jan,2008. The relationship between the postoperative visual acuity improvement rate and the factors were analyzed and summarized,such as the duration of diabetes, the preoperative stage of proliferative diabetic retinopathy,different vitreous substitutes , preoperative PRP .Results: Duration of diabetes affects postoperative visual acuity improvement rate with no statistic difference(p=0.505>0.05);the preoperative stage of proliferative diabetic retinopathy affects postoperative visual acuity improvement rate with statistic difference(p=0.034﹤0.05),and eyes of the IV PDR group tend to have better postoperative visual acuity improvement rate than the eyes of V PDR and VI PDR groups;the postoperative visual acuity improvement rate of eyes of non-tamponade group which mostly contain PDRIV eyes with light ocular fundus process is 90.9%, the postoperative visual acuity improvement rates of eyes of silicon-oil tamponade and inert-gas tamponade groups which mostly contain PDRV and PDRVI eyes with severe ocular fundus process are 63.6% and 53.6% ;whether preoperative PRP is performed or not affects postoperative visual acuity improvement rate with no statistic difference(p=0.396>0.05)。Conclusions:1.Patients'visual acuity can be well improved by vitrectomy, which indicated that vitrectomy is an effective method to proliferative diabetic retinopathy nowadays. 2. Duration of diabetes in this way is unrelated with postoperative visual acuity improvement rate in cases of this group. 3. Eyes of the IV PDR group tend to have better postoperative visual acuity improvement rate than the eyes of V PDR and VI PDR groups; in addition eyes of non-tamponade group which mostly contain PDRIV eyes with light ocular fundus process have better postoperative visual acuity improvement rate .Therefor, vitrectomy should be performed in early time for patients with proliferative diabetic retinopathy to obtain a better visual prognosis. 4. Whether preoperative PRP is performed or not has no relationship with postoperative visual acuity improvement rate.5.The augmentation of operative sample size is needed to explore roles of different factors in the visual acuity improvement rate after surgery for proliferative diabetic retinopathy. |
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