Dosage relevance of trace PFD with toxicity in rabbit retina / 吉林大学学报(医学版)

Objective Through pathological and histological examination on retina to research the dosage relevance of trace PFD with toxicity in rabbit retina,and provide experimental reference basis for clinical practice.Methods Fourty eight eyes from 24 experimental rabbits were randomly divided into experimental group(36 eyes) and control group(12 eyes).The experimental one was divided into 3 groups,12 eyes in each group.The surface of rabbit retina was directly injected with 30,50,and 100 ?L liquids of PFD and BSS.The conditions of rabbit retina were observed under ophthalmoscope every day after the liquid injection.The sections of retina tissue were observed under transmission electron microscope in each experimental and control groups at the 4th,7th,14th and 21th day after injection.Results All samples were normal by ophthalmoscope examination while no pathological change of retina was found at various time points .At the 4th day,none substantial damage had been made in any dosage groups by transmission electron microscope examination except for 100 ?L group.Only one retina of 100 ?L group showed that the space around cell nucleus broadened appreciably,slightly atactic nucleus and slightly compact cytoplasm.It showed some early changes.From the 7th day,similar pathological changes were found: damage on outer segments of light receptor and outer plexiform layer,properties changes of light receptor,forming of vesicles of inner nuclear cells,damage of ganglion cell,dying of inside retina,actions of gulping cells in retina,swallow of film plates by pigment epithelial cell of retina,and dropping of top fine hair. But the retina of control group had no pathological changes.Conclusion Trace PFD exists in eyes.There is no relevance between poisonous development of retina and remaining dosage of PFD.However,large remaining of PFD can lead to retina toxicity early.

Lens-sparing vitreoretinal surgery for treatment of giant retinal tears / 中华眼底病杂志

Objective To evaluate the effect of vitreoretinal surgery with lens sparing technique in treating the detachment with giant retinal tear(GRT) associated with proliferative vitreoretinopathy(PVR). Methods Thirty one consecutive eyes with GRT underwent vitrectomy were analysed retrospectively. Operative techniques included peeling of pre retinal membrane, injection of perfluorodecalin liquid, retinotomy and retinectomy,endolaser,and silicon oil or C 2F 6 gas tamponade. Lens sparing vitrectomy was performed in 28 phakic eyes. Follow up period ranged from 11 to 34 months. Results Anatomic retinal attachment was achieved intraoeratively in 29 eyes. In 16 eyes of 28 eyes with postoperative cataract formation,3 eyes underwent cataract surgery with or without intraocular lens implantation. The corrected final visual acuity ranged from 0.4 to 0.01. Conclusion Most phakic eyes of retinal detachment with GRT PVR can be successfully operated on with an outcome of improving the visual acuity by using techniques of lens sparing vitrectomy, perfluorodecalin liquid and silcone oil tamponade.

Experimental Studies on the Retinal Responses to Intravitreal Perfluorocabon Liquids

Perfluorocarbon liquids (PFCLs) are useful tools during vitreous surgery for complicated retinal detachments. Generally, these liquids are used as short-term vitreous replacement without retinal toxicities. But long-term tolerance of intraocular fluorochemicals is not established. We evaluated long-term tolerances to intraocular perfluorophenanthrene(Vitreon) or perfluorodecalin(DK-line) in the rabbit retina for a period of up to 3 months. Three days after C3F8 gas-compression of the vitreous, 1.2ml of highly purified PFCLs were injected into 26 rabbit eyes. Control eyes received same volumes of balanced salt solution. Eyes were examined by indirect ophthalmoscopy and light and electron microscopy. Clinically PFCLs were emulsified and dispersed into small bubbles after 2-3 weeks. Mild posterior subcapsular cataracts and vitreous opacities were observed after long-term retention of PFCLs. Histopathologically, at 1 week after surgery, several epiretinal macrophages were present in both groups. Focal disarrangements of photoreceptors were observed in perfluorodecalintreated group. At I month after surgery, protrusion of Muller cell, dropdown of photoreceptor nuclei, loss of photoreceptors, outer and inner segments and retinal pigment epithelial hypertrophy were observed. In perfluorodecalin-treated group, atrophy in outer nuclear layer and thinning of all the retinal layers occurred. At 3 months after surgery, small oil-like droplets were scattered throughout the retinal layers and retinal pigment epithelium in perfluorodecalin-treated group. These findings were almost totally confined to the lower part of retina that has been long-term contact with the liquids. Our findings suggest that perfluorodecalin is more toxic to the retina than perfluorophenanthrene. Both liquids are not adequate for long-term vitreous replacement, but may be useful for short-term intraoperative use.

The Management of Giant Retinal Tear by use of Perfluorodecalin(DK-line(R) and Silicone Oil

Recently, various types of perfluorocarbon liquids are used to treat the retinal detachment due to giant tear. The authors treated 3 cases of giant retinal tear with perfluorodecalin and silicone oil. After pars plana vitrectomy, posterior retinal flap was unfolded by injection of perfluorodecalin and exchanged it for silicone oil subsequently. Silicone oil was removed after 4 weeks. Endophotocoagulation and scleral buckling were taken in all cases, and lensectomy for normal lens in 1 case. After the close observation for 6 months or more, retina was reattached successfully in 2 of 3 cases. Because of proliferative vitreoretinopathy, reinjection of silicone oil was needed in 1 case. Perfluorodecalin and silicone oil were useful materials to reattach the folded retinal flap of giant retinal tear.

Experimental Evaluation of Intravitreal Perfluorodecalin and Silicone Oil in the Rabbit as a Long-acting Intraocular Tamponade

Perfluorodecalin, which is one of the perfluorocarbon liquids, is not established safety in use of long-acting intraocular tamponade. Therefore, to determine its safety we injected it alone and combined with silicone oil into the vitreous of vitrectomized eyes. We evaluated the changes of the fundus, electroretinogram, histopathology as light and electron microgragh after lensectomy and vitrectomy in pigmented rabbits periodically. In rabbits replaced with perfluorodecalin alone, fundus showed mild proliferative vitreoretinopathy and micrographs showed the destruction of the inner and outer segments of the photoreceptors. In rabbits replaced with perfluorodecalin and silicone oil, fundus showed more severe proliferative vitreoretinopathy than perfluorodecalin alone and micrographs showed the destruction of the entire retina. In electroretinogram, the amplitude was decreased markedly. So, it is considered that perfluorodecalin was not tolerant in case of longacting intraocular tamponade and also perfluorodecalin combined with silicone oil developed severe proliferative vitreoretinopathy.