Objective To investigate the killing effect of herpes simplex virus thymidine kinase/gancyclovir (HSV-tk/GCV) suicide gene therapy system on retinoblastoma (Rb) cells and the mechanism of bystander effect. Methods By using liposome, pCMV/hytk-IREShrGFP plasmid was transferred into HXO-Rb44 cells. A fluorescence microscope was used to detect the transduction effeciency. The positive cell clones were selected by hygromycin and were named HXO-Rb44/tk. RT-PCR was resorted to demonstrate the sucessful transduction and transcription of hytk gene in the HXO-Rb44/tk cells. The morphologic features and growth patterns of HXO-Rb44/tk were compared with those of HXO-Rb44. Then MTT assay was used to determined the killing effect of GCV on HXO-Rb44/tk and the mixture of HXO-Rb44/tk and HXO-Rb44 in different ratios ("bystander effect"). The mechanism of bystander effect was studied by the experiment of supernatant shifting. Results The transduction effeciency was 20%. 530bp hytk gene strand was seen through HXO-Rb44/tk RT-PCR. There were no differences in the morphologic features or the growth patterns between HXO-Rb44/tk and HXO-Rb44. HXO-Rb44/tk was more sensitive to GCV than was HXO-Rb44. The cytotoxicity of HXO-Rb44/tk was dose and time dependent. An obvious "bystander effect" was seen even with low proportions of HXO-Rb44/tk, but this effect disappeared when transferring GCV containing supernatant of HSV-tk-positive cells to the negative cells. Conclusion The transfer of the HSV-tk gene into Rb cells followed by the administration of GCV could serve as a model for gene therapy for retinoblastoma, the "bystander effect" in HSV-tk/GCV-mediated gene therapy occurs by transfer of GCV metabolite from cell to cell through gap junction.

Objective　To observe the clinical effects of human amniotic membrane as an alternative substrate for wrapping hydroxyapatite ocular prosthesis implants.Methods　After enucleation, hydroxyapatite orbital implants wrapped by human amniotic membrane were implanted with four rectus sutured to the implants .Among them, 4 cases were given primary implantation and 3 cases secondary implantation.Results　After 8 to 39 week follow-up, it was found that in 6 cases, the eyelids were plump and prosthesis moved well, but one implant was removed because of failure of scleral patch graft for implant exposure.Conclusion　The clinical results were satisfactory for ocular prosthesis implantation of hydroxyapatite sphere wrapped by human amniotic membrane, which may be considered as an alternative substrate for ocular prosthesis implants wrapper.

Objective　 To probe into the operative methods, effects and reasons of failure for retinal detachment with choroid detachment.Methods　Thirty-one cases (31 eyes) with choroid detachment and proliferative vitreous retinopathy (PVR) were given vitreoretinal surgery, stripping of pre-membrane and injection of inert gas or silicone oil into vitreous body. Results　The retina was totally reattached in 22 cases (22 eyes), partly reattached in 5 cases (5 eyes),unattached in 4 cases (4 eyes),which was accounted for 70.9%,16.1% and 12.9% in 31 cases (31 eyes) respectively. Visual acuity improved in 25 eyes and no change in 5 eyes and decreased in 1 eye. The main cause of operation failure was possibly related to the severe anterior PVR. Conclusion　Vitreoretinal surgery can improve the successful rate of retinal detachment with choroid detachment.

Objective　To analysis the relation of the diameter of continuous curvilinear capsulorhexis and other factors with the capsular block syndrome.Methods　We not only analyzed the etiology and clinical characteristic of six cases in intraoperative,early postoperative and lately postoperative,but also discussed the method of treatment.Results　(1)When the diameter of CCC was smaller than the one of IOL's optic , the CBS easily happened; (2)When the hoops of the hydroview IOL had a smaller anterior angle and larger optic, the CBS easily happened; (3)When the viscoelestic material and cortex were stayed in capsular or anterior chamber, the CBS easily happened.Conclusion　(1)Generaly speaking the size of the CCC should right on the edge of the IOL's optic part; (2)To hydroview IOL, we should choose the one which had a larger anterior angle and a smaller optic; (3)Viscoelastic material which should be cleaned and there was no the rest cortex stayed in the capsular.

Objective　To analyze the surgical results of uveitis-complicated cataract.Methods　Cataract phacoemulsification surgery was performed on 31 eyes (29 patients) due to uveitis (iridocyclitis 14 eyes, Fuchs heterochromic cyclitis 7 eyes, intermediate uveitis 7 eyes, Vogt-koyanagi-harada syndrome 2 eyes, and sympathetic ophthalmia 1 eye). Follow-up period was 5～28 months, averaging 15 months. Retrospective analysis was made.Results　Postoperative visual acuity≥0.5 was 80%. One eye (Vogt-koyanagi-harada syndrome) showed severe anterior uveitic reaction; One eye (iridocyclitis) had fibrinous membranes on IOL, and white debris on IOL were found in 2 eyes (intermediate uveitis).Conclusion　By using less traumatic phacoemulsification technique to ocular tissue, taking meticulous care to avoid stimulating iris, cleaning up cortex thoroughly during surgery and implanting the IOL in the bag, less inflammatory reaction, less complication and better vision acuity postoperatively at relative quiescence period of uveitis can be achieved.

Objective　To evaluate the effect of modified suction ring in laser in situ keratomileusis(LASIK) for special eyeballs.Methods　Those eyeballs that couldn't be sucked successfully with regular suction ring were performed with modified suction ring, and the characteristic of those eyes was analyzed.Results　Fifteen eyes of 9 cases were included in this study and were sucked successfully with modified suction ring with intact corneal flap.Eight eyes of 5 cases had small corneal power especially in the peripheral section. The corneal power in the peripheral section of 7 eyes was less than 41D. Corneal diameter of 1 eye was 9.5mm and 6 eyes of 3 cases had small palpebral fissure.Conclusions　The modified suction ring is safe and effective for those eyes with flat cornea, small corneal diameter and small palpebral fissure.

Objective　To explore the clinical superiority of two kinds of chopping nucleus methods in phacoemulsification——etch and turn technique, stop and chop technique.Methods　Three hundred and sixty-five eyes were performed with phacoemulsification, among which 85 eyes were performed with turn technique and 280 eyes were performed with chop technique.The results of the two kinds of chopping nucleus were analyzed.Results　(1)Time of chopping nucleus:time of turn technique averaged 81.26 seconds while chop technique averaged 40.71 seconds; (2)Visual acuity in the first week after operation:turn technique:vision of 76 of 85 eyes were 0.5 of better, 7 eyes were 0.2～0.5(8.2%) and 2 eyes were 0.2 or worse; chop technique: vision of 253 of 280 eyes were 0.5 or better (90.4%), 21 eyes were 0.2～0.5(7.5%) and 6 eyes were 0.2 or worse (2.1%);(3)Reaction of corneal endothelial cells after the operation: central endothelium rugosity appeared in 4 eyes (4.7%) with turn techinque and in 7 eyes (2.5%) with chop technique. Conclusion　The operation of the former is less difficult and the chopping nucleus time is longer. The time of the operation on the latter is shorter and it is appriate for hard nucleus and should be applied and spreaded. There are no marked differences as for the vision after the operation and the microcorneal injury between them.

Objective　To evaluate the therapeutic efficiency of reversed lamellar keratoplasty for bullous keratopathy, Terrien's marginal degeneration and ocular chemical burns.Methods　Twenty eyes of patients with bullous keratopathy, twelve eyes with Terrien's marginal degeneration, ten eyes with chemical burns were recruited in this study.Diseased tissues were removed by means of dissection.Reversed lamellae corneal tissues which had been prepared by cryopreservation were thawed and rinsed. Then the prepared posterior corneal lamellae was turned over, endothelium facing upwards. The diameter of the graft should be 0.5～1.0mm larger than that of the recipient bed. The reversed donor posterior lamellae was sutured into the host keratectomy bed with 10-0 nylon sutures continuously or interruptedly.Results　Allograft reaction episode occurred only one (chemical burn) of the total 42 eyes enrolled.The grafts of the rest 41 eyes maintained clear or semitransparent for 1～5 years. Graft edema could be observed within 2～4 weeks postoperatively. Postoperative interface separation was not found. For all 20 patients with bullous keratopathy, the symptoms of pain disappeared. The visual acuity improved 2～3 lines of Snellen among eleven of twelve patients with Terrien's marginal degeneration. The visual acuity improved 2～3 lines of Snellen with four patients with chemical burns.Conclusion　The technique of reversed lamellar keratoplasty can be applied successfully for tectonic reconstruction of corneal surface such as bullous keratopathy, Terrien' s marginal degeneration and also chemical burns.The effects of therapy was satisfactory.

Objective　To assess the roles of the soft contact lens(SCL) in the treatment of bullous keratopathy.Methods　Seventeen cases with bullous keratopathy wore SCL continuously and disposed it each month. All cases were followed up to observe whether the clinical symptoms were relieved and complications appear.Results　 Seventeen cases were followed up for 2 to 22 months. The results suggested that the clinical symptoms were relieved significantly without complications.Conclusion　SCL can relieve the clinical symptoms and improve the life quality of patients with bullous keratopathy significantly.

Objective　To study the causes of failure to IOL implantation during cataract surgery.Methods　We reviewed 540 eyes in which 23 eyes were failed to implant IOL during cataract surgery.Results　Detachment of suspended zonular ligament, rupture of posterior capsule and vitreous prolapse are the main factors influencing IOL implantation during cataract surgery.Conclusion　Improvement of surgical technique and reduction of complications are the key points for the IOL implantation successfully during cataract surgery.