Objective To evaluate the indications, effectiveness and complications of vitreoretinal surgery using the 25G transconjunctival sutureless vitrectomy system (TSV25G) under the topical anesthesia. Methods The clinical and follow-up data of 22 eyes of 22 patients undergone vitreo-retinal surgery using TSV25G under the topical anesthesia were retrospectively analyzed. All of the patients were monocular sickened, including idiopathic macular hole in 10 eyes, idiopathic macular pucker in 6, vitreoretinal traction syndrome in 4, and vitreous hemorrhage associated with branch retinal vein occlusion in 2. Peeling of epiretinal membrane and/or internal limiting membrane, intra ocular laser coagulation, air-fluid exchange and tamponiding of C3F8 were performed according to the condition of diseases. The postoperative follow-up was 1-11 months, with the mean duration of 6.4 months. The effect of analgesia, cooperation with the patients, operative effect and complications in and after the surgery were observed. Results The operations finished successfully in all of the eyes under the topical anesthesia. The operation duration ranged from 20 to 25 minutes with average of 22 minutes. The patients cooperated with the doctor well without any discomfort. Two days after the surgery, edema of the wounded conjunctiva was found, and recovered 7 days later. A light pigment dot on the surface of the sclera could be seen at the first month. The complic ations included transient increasing of intraocular pressure in 2 eyes, feather-like opacity of lens in 5 eyes, vitreous hemorrhage in 1 eye, and air-bleb under conjunctiva in 2 eyes. No other complications related with the cut were fo und. The macular hole closed in 9 eyes with idiopathic macular hole, and the other 1 had the smaller but not closed hole. Idiopathic macular pucker, vitreoretinal traction syndrome, and vitreous hemorrhage associated with branch retinal vein occlusion were cured successfully. Conclusions Vitreoretinal surgery using the TSV25G under the topical anesthesia has many advantages such as simple procedure, short operation time, micro-invasion, less complications and rapid revovery, and mainly serves simple manipulation in some simple diseases such as idiopathic macular hole, vitreo-retinal traction syndrome, and simple hemorrhage. (Chin J Ocul Fundus Dis，2004，20：133-136)
Objective To explore the correlation between retinal extracellular edema and vitreous contraction in rabbits. Methods Seventeen pigmented rabbit models with retinal vein occlusion (RVO)was set up by laser photocoagulation. Retinal vascularity area was pathologically examined 1 month later.The vitreous gellength under the gravity condition and the percentage of its weight in the rabbits with extraeellular edema was observed. The mechanisms were investigated by Western immunoblotting of type II collagen.Results Extracellular edema was found in 13 experimental eyes 1 month after the formation of RVO (76.5~) with contracted vitreous gel and released watery liquid, and the a component of type II collagen was cross-linked together to form high-molecular-weight components of 1] and 7, which weakened the stability of collagen net structure.Conclusions Vitreous contraction and retinal extracellular edemawere correlated. The main reason may be the cross-links of vitreous collagen that damages the stability of collagen structure. (Chin J Ocul Fundus Dis，2004，20：2-32)
Objective To investigate the effect of long-term intraocular retention of domestic perfluorocarbon liquid (PFCL) on morphology and histology of ocular tissues. Methods A total of 18 New-Zealand rabbits were randomly divided into 3 experimental groups, whose left eyes underwent intraocular injection with 0.3, 0.6, and 1.0 ml PFCL, respectively. All of the right eyes of the rabbits were in the control group. The morphological, electrophysiological and histological changes of the ocular tissue were observed 4, 8, and 12 weeks after the injection. Results No clinically significant retinopathy but only mild morphological changes were found in group 1 and 2, while obvious morphological and histological changes were found in group 3. Mild morphological and histological changes were found in all of the rabbits 4-8 weeks after the injection while significant ones were found 8-12 weeks after the injection. The results of electroretinography indicated a statistically significant decline of amplitude of b wave in group 3. Conclusions Long-term intraocular retention of few PFCL may cause mild histological changes but not affect the clinical function. Plentiful PFCL remains in eyes may lead to toxic reaction to the ocular tissue. (Chin J Ocul Fundus Dis, 2006, 22: 128-130)
Objective To investigate the retinal toxicity and verify the safe dose of intravitreal injecting fluconazole. Methods Twelve healthy adult white rabbits were divided at random into 6 groups：a normal control group and 5 groups received intravitreal injection of a single dose of fluconazole ranging from 10 to 200 mu;g respectively.Retinal toxicity was examined by ophthalmoscopy, electroretinography, light and transmission electron microscopy (TEM) on the third and fourteenth day after injection. Results The ultrastructures of the retinal tissues of the normal control group and fluconazole 10～150 mu;g groups were normal on the third and fourteen day after injection.The light microscopy and TEM showed that cells of all the retinal layers in the 200 mu;g group revealed apparent degenerative changes on the fourteenth day after injection, and the light microscopic picture showed the vacuolar degeneration of outer segments of photoreceptors, the nuclei in outer nuclear layer drop out into inner segments, the vacuolar degeneration of nerve fiber layer, and the proliferation of pigment epithelium. TEM revealed expansion of paranucl eus space and karyopyknosis of the bipolar cells, the swelling of nerve fibers and disappearance of the synapses in the inner plexiform layer, the vacuolation and disappearance of microvilli of the pigment epithelium cells. Conclusion The safe dose of fluconazole injected intravitreally should be 100～150 mu;g. (Chin J Ocul Fundus Dis，2000，16：139-212)
Objective To review the distribution and shifting trends of cultured bacteria from the aqueous humor and the vitreous body. Methods A retrospective analysis on distribution of Gram′s stain, the distribution and change of isolates was performed in 522 specimens (aqueous humor,261 and vitreous body,261) of patients with suspected endophthalmitis during a 10-year period (1989-1998). Results The positive cultures were 119 (aqueous humor,44 and vitreous body,75) of 522 specimens. The average positive rate was 22.8%. Gram-positive cocci constituting 45.4%(54) of total isolates followed by Gram-negative bacilli,34.5%(41);Gram-positive bacilli, 20.2%(24). In the positive bacterial cultures, enterobacteriaceae was the most common isolate, 18.5%, and the next was micrococcus, 16.0%; coagulase-negative staphylococcus,12.6%; and pseudomonas,10.9%.Comparing the data from 1989 through 1993 with the data from 1994 through 1998, the frequency of Gram-positive cocci had no significant change, while the frequency of Gram-positive bacilli was decreased and the percentage of Gram′s-negative bacilli was increased. Conclusions Gram-positive cocci and Gram-negative bacilli are the predominant pathogens of bacterial endophthalmitis. The percentage of Gram′s-negative bacilli has increased for 5 years. It is very important to comprehend the distribution and shifting trends of these pathogenic bacteria for diagnosis, prevention and treatment of bacterial endophthalmitis. (Chin J Ocul Fundus Dis, 2002, 18: 104-105)
Objective To reveal the fibrillar network in vitreous and the effect of plasmin on this network.Methods 20 vitreous gels of freshly slaughtered pigs were divided into 2 groups, the gels in first group were digested by 3 Uplasmin (3 U/ml) at 37c for 24 hours respectively, the second group received the same PBS as control. After digestion, gels were fixed in neutral buffered formalin solution. Samples from vitreous base, cortex and the central region were observed by the technique of freeze etching electron microscopy.Results In vitreous collagen fibril network was in a three-dimensional array, collagen fibril density showed marked differences, central vitreous had the sparse fibril density, the cortex denser and the basal vitreous densest. After digestion by plasmin, the collagen fibrillar network was destructed.Conclusion Collagen fibrils in vitreous present spatial arrangement regularly, plasmin can lead to destruction of the fibrillar network.(Chin J Ocul Fundus Dis，2003，19：179-181)
Objectivｅ To investigate the histopathologic charact eristic of the vitreous herniation out of sclerotomy site during vitrectomy. Methods Twenty specimens of tissues herniated at vitrectomy site were collected. The paraffin sections or fresh smears were stained with hematoxylineosin and examined under light microscope. The specimens were collected from the affected eyes with rhegmatogenous retinal detachment (9 cases), traumatic retinal detachment (1 case), miscellaneous vitreous hemorrhage (6 cases) and intraocular foreign body (4 cases). Results The herniated tissues were found to be retina in 4 cases, ciliary tissue in 1 case, retina and ciliary tissue in 1 case, uvea in 1 case, and hyaloid tissue in 13 cases. Conclusion There were not only vitreous, ciliary epithelial cells and pigment containe depithelia, but also ciliary body, retina and uvea in the prolapsed tissues of sclerotomy site, which might be related to the occurence of some clinical complications. (Chin J Ocul Fundus Dis,2001,17:99-101)
Objective To describe cultured human retinal pigment epithelial (RPE) cells transdifferentiation and investigate the effects of human vitreous fluid on the morphologic and cytoskeleton changes of RPE cells in vitro. Methods Cytoskeleton characteristics in the 2nd, 5th, 8th passage of RPE cells in normal culture, which included cytokeratin 18 (CK18) and α-smooth muscle actin (α-SMA) were analyzed by Western blot. RPE cells were cultured in human vitreous-conditioned medium (VCM) at the concentration of 1∶4 for 6 days, morphologic changes were examined by light and electron microscopy, and cytoskeleton characteristics were analyzed by imunocytochemistry and Western blot. Results During culture in vitro, RPE cells lost epithelial characteristics and aquired fibroblast-like phenotype. The expression of CK18 was the highest at the 5th passage, and it decreased in the following passage, but α-SMA increased gradually. The morphologic transdifferentiation from epithelial to fibroblast-like cells of RPE was accelerated by VCM. Ultrastructural changes such as decreased microvilli and gradually increased rough endoplasmic reticulum and Golgi complex were found during the cultivation. CK18 produced by RPE cells decreased in VMC (P＜0.05), and α-SMA increased (P＜0.01). Conclusion Morphologic changes in epithelialmesenchymal transdifferenetiation of RPE cells are stimulated by VCM and accomplied by the shift of cytoskeleton proteins, The results imply that cells migration may be decreased and contraction may be enhanced in VCM. It may suggest that vitreous accelerates the pathogenesis of PVR and RPE cells play an important role. (Chin J Ocul Fundus Dis, 2002, 18: 289-292)
Purpose To explore the role of scanning laser tomography in the assessment of macular hole surgery. Methods Fifteen eyes of 14 patients with macular holes underwent scanning of their affected macular area using the Heidelberg retina tomograph (HRT). The significance of topographic changes postoperatively were determined in eleven eyes which received vitrectomy surgery. The scan field was set at 15°of the retina and the depth was set to 1.5 mm or 2.0 mm. All the measurements were taken for 3 times and the average value of the 3 measurements was used. Results The average hole area was (0.499±0.34) mm 2 and the maximal depth of the hole was (0.284±0.11) mm. Topographic difference analysis of the eleven eyes showed a significant reduction in the height of the retina after vitrectomy. The maximal depth of the hole was (0.063±0.04) mm postoperatively. Conclusion Scanning laser tomography provides an objective evaluation of the anatomic outcome of the macular hole surgery. (Chin J Ocul Fundus Dis, 2002, 18: 125-127)
Objective To investigate the dosage, efficacy and safety of intrav itreal injection of plasmin in producing posterior vitreous detachment (PVD), an d the possible role of plasmin in degrading adhesion glycoproteins of inner limiting membrane (ILM).Methods Twenty eyes of young human cadavers within 24 hours after death were divided into 4 groups that received 0.1 ml balanced salt solution (group 1) as control, 1 (group 2), 2 (group 3), or 3 (group 4) U of human plasmin. Optical and transmission electron microcopies were performed to examine the ultrastructure of the vitreoretinal interface. Electron-immunocytochemical techniques were carried out on ILM to estimate the content of fibronectin (FN) and laminin (LN). Flow cytometry was used for cell viability analysis of variance (ANOVA) and Tukey-test was employed for statistical analysis. Results Microscopy demonstrated that plasmin especially in group 4 cleaved the attachment of the vitreous collagen fibrils to the ILM with no evident damage to the inner retina. The content of LN, FN in ILM decreased with injection of plasmin (group 3 and 4 had statistical significance from control group for FN,P＜0.05; for LN in group 4, P＜0.05). Retinal cell viability was similar for plasmin-treated and control eyes. Conclusion Human plasmin disrupts the attachment of posterior hyaloid to the ILM with no morphologic changes of the inner retina. PVD is induced mostly with injection of 3 U plasmin. (Chin J Ocul Fundus Dis，2003，19：42-45)