Showing papers on "Vitreous Detachment published in 2000"

Intravitreal injection of hyaluronidase cannot induce posterior vitreous detachment in the rabbit.

Abstract: PURPOSE: To investigate whether intravitreal injection of hyaluronidase can induce posterior vitreous detachment (PVD) in the rabbit. METHODS: One eye each of 12 New Zealand white rabbits received intravitreal injection via the pars plana of 20 IU of hyaluronidase (0.1 mL reconstituted in sterile balanced salt solution [BSS]) into the midvitreous cavity. The fellow eye of each rabbit received a vitreous injection of 0.1 mL of BSS. At 3 and 6 months after intravitreal injection, four and eight rabbits were killed, respectively, and the eyes were enucleated. After fixation, scanning electron microscopy was performed to study the vitreoretinal interface. RESULTS: At 3 and 6 months after injection, scanning electron microscopy showed that the retinal surfaces in eyes that received either hyaluronidase or BSS were covered with vitreous collagen fibers. No eyes, even those that received hyaluronidase over a period of 6 months, had the smooth retinal surface consistent with a bare internal limiting lamina that suggests the development of PVD. CONCLUSION: Hyaluronidase cannot induce PVD in the rabbit over a 6-month period after vitreous injection.

Acute posterior vitreous detachment: the predictive value of vitreous pigment and symptomatology

Abstract: Aim—To establish whether the presence of a retinal break can be predicted either by the presence of a positive Shafer’s sign (pigment granules in the anterior vitreous) or symptomatology in patients presenting with an acute posterior vitreous detachment (PVD). Methods—200 eyes of 200 phakic patients with a symptomatic PVD of less than 1 month’s duration underwent documentation of symptomatology and examination of the anterior vitreous for the presence of pigment granules. Indentation ophthalmoscopy was then carried out by an experienced vitreoretinal surgeon with no knowledge of the symptomatology or anterior vitreous gel examination findings. A second prospective group of 115 consecutive patients were assessed in a similar manner before primary rhegmatogenous retinal detachment repair. Results—In 200 eyes presenting with an acute PVD, 25 were found to have an associated retinal break, 23 of which were also Shafer positive. In 115 eyes presenting for retinal detachment repair, 111 had an associated PVD and were found to be Shafer positive. Symptomatology was not predictive of an associated retinal break in the PVD group or in those presenting with a retinal detachment. Conclusion—The increased use of Shafer’s sign is recommended as a valuable aid in determining which patients require urgent referral for an expert retinal examination. It is not possible to predict those patients with a retinal break secondary to PVD on the basis of symptomatology alone. (Br J Ophthalmol 2000;84:1264‐1268)

Pars plana vitrectomy for regression of choroidal neovascularization with age-related macular degeneration.

Abstract: . Objective: In age-related macular degeneration, the posterior vitreous surface often remains attached to a higher degree than expected for the patient's age, suggesting the involvement of the posterior vitreous membrane in the pathophysiology of choroidal neovascularization. Thus, we performed simple pars plana vitrectomy and artificial posterior vitreous detachment in order to induce regression of choroidal neovascularization. Methods: Vitrectomy was performed in 12 eyes of 11 patients with age-related macular degeneration in whom the posterior vitreous surface remained attached, and in whom there was evidence of highly active choroidal neovascularization. The posterior vitreous membrane was artificially detached during surgery, but photocoagulation and/or a subretinal procedure for choroidal neovascularization was not performed. Patients underwent fluorescein and indocyanine green angiography both pre- and postoperatively to assess the status of choroidal neovascularization. Results: Six months after surgery, 6 of the 12 eyes showed regression of choroidal neovascularization, and in 2 eyes it had disappeared completely. Subretinal exudative changes in 8 eyes had improved. Visual acuity testing showed improved vision in 4 eyes, unchanged vision in 4 eyes, and worsening of vision in 4 eyes. The final best corrected visual acuity was 10/20 or better in one eye, 10/20 to 20/200 in 7 eyes, and 20/200 or worse in 4 eyes. Conclusion: The results of the present study suggest the involvement of the posterior vitreous membrane in the pathophysiology of age-related macular degeneration. Furthermore, the minimally invasive pars plana vitrectomy may represent a new treatment for age-related macular degeneration.

Dome-shaped detachment of premacular vitreous cortex in macular hole development.

Abstract: PURPOSE: To clarify the role of the posterior vitreous cortex in macular hole development, we evaluated the follow-up findings of clinical observations and optical coherence tomography (OCT) images of macular holes in early stage. METHODS: The vitreoretinal tomography was examined and followed in eyes with stage 1 and 2 macular holes with OCT. RESULTS: The posterior cortical vitreous was identified in 12 of 17 eyes with early-stage macular holes by OCT (71%). In these eyes, the detached posterior vitreous appeared to be merged to the fovea and the disc. The vitreoretinal separations showed typically dome-shaped. A long scan along the papillomacular axis also delineated the posterior vitreous face as dome-shaped perifoveal vitreous detachment with adhesion to the fovea and disc. Repetitive OCT examinations clearly demonstrated the course of development of the macular hole. CONCLUSIONS: The dome-shaped vitreoretinal separation seen with OCT gives rise to an idea that the posterior vitreous cortex may not be taut but slack, and would not cause a continuous tractional force even in early-stage macular holes. This finding brings us an idea that the tangential traction at the fovea may be generated by fluid movements, rather than by contraction of the cortical vitreous.

Spontaneous closure of macular hole after posterior vitreous detachment.

Abstract: Macular holes can be treated with surgically-induced vitreous detachment and gas tamponade. The authors report a case of a macular hole that closed spontaneously after the development of posterior vitreous detachment (PVD). Optical coherence tomography (OCT) revealed a small full-thickness macular hole with perifoveal cystic changes in a 25-year-old female with a central scotoma at her initial visit. There was no evidence of PVD. Five months later, PVD was observed and the macular hole disappeared. OCT performed three months later showed macular hole closure and resolution of the perifoveal cystic changes. The physiologic pit was restored in the fovea. OCT is useful to detect and monitor the morphologic changes of a macular hole.

Reattachment of retina and retinoschisis in pit-macular syndrome by surgically-induced vitreous detachment and gas tamponade.

Abstract: The origin of the subretinal fluid in pit-macular syndrome is unknown. Using optical coherence tomography, the authors observed that an optic disk pit is not a true pit but a cystic cavity covered with a superficial layer of the optic disk in a patient with retinal detachment and retinoschisis. The cyst was connected to the intraretinal space of the retina, which was split in several layers, or the retinoschisis in the papillomacular area. Vitrectomy and gas tamponade were performed to treat the patient. During surgically-induced vitreous detachment, strong vitreoretinal attachment at the disk margin and the fovea was observed. After surgery, the cystic space at the optic disk disappeared and the retinal detachment and retinoschisis reattached. Vitreous traction may play a role to introduce the fluid from the optic cyst to the subretinal space through the superficially split retina.

Biomicroscopic vitreous observation using a 3 CCD video camera and a personal computer for image capture and archiving

Abstract: The purpose of this study is to evaluate the clinical usefulness of a newly developed biomicroscopic vitreous observation system Vitreous observation was performed in 300 eyes with age- or disease-related vitreous changes using a 3 CCD video camera mounted on a slit-lamp biomicroscope and connected to a personal computer for real-time observation and especially for the capture and archiving of images Various types of fundus lenses were used to scan the vitreous status systemically from the posterior pole to the vitreous base This system allowed us to obtain and immediately review the images of the vitreoretinal relationship The image quality was sufficient for clinical evaluation of the vitreous status We were able to identify some variations of posterior vitreous detachments and clarify the changes of the vitreoretinal interface in the study eyes This system is very useful for the dynamic observation and documentation of vitreous images in order to determine the role of vitreous in many vitreoretinal disorders Furthermore it is more convenient and affordable than previous methods