Effects of vitrectomy and phakectomy on the drainage of the vitreous compartment

Algvere, Peep; Bill, Anders

doi:10.1007/bf00408167

Cited by 7 publications

(3 citation statements)

References 9 publications

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“…The ex vivo eyes showed a relative obstruction of Gd-DTPA diffusion from the vitreous cavity to the posterior chamber, probably due to the dense vitreous condensation in this region. 36,37 The pooling of Gd-DTPA in the posterior chamber of these eyes was due to the strong iris-lens apposition in rabbits where the iris acts as a one-way valve permitting anterior flow only. 38 There are several differences in the anatomy and physiology of the rabbit eye that have to be considered before extrapolating the results of this study to humans.…”

Section: Discussionmentioning

confidence: 99%

Controlled Drug Release from an Ocular Implant: An Evaluation Using Dynamic Three-Dimensional Magnetic Resonance Imaging

Kim

Robinson

Lizak

et al. 2004

Invest. Ophthalmol. Vis. Sci.

116

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In vivo, episcleral implants at the equator of the eye did not deliver a significant amount of Gd-DTPA into the vitreous, and no compound was identified in the posterior segment. A 30-fold increase in vitreous Gd-DTPA concentration occurred in the enucleated eyes, suggesting that there are significant barriers to the movement of drugs from the episcleral space into the vitreous in vivo. Dynamic three-dimensional MRI using Gd-DTPA, and possibly other contrast agents, may be useful in understanding the spatial relationships of ocular drug distribution and clearance mechanisms in the eye.

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Section: Discussionmentioning

confidence: 99%

Controlled Drug Release from an Ocular Implant: An Evaluation Using Dynamic Three-Dimensional Magnetic Resonance Imaging

Kim

Robinson

Lizak

et al. 2004

Invest. Ophthalmol. Vis. Sci.

116

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“…Furthermore, the severe nature of PVR in this model coupled with its long lasting proliferation stimulus provides the rational for a slow delivery drug therapy. Single intravitreal injections of either agent have a relatively short half life (further shortened by vitrectomy, aphakia, and postoperative inflammation), 21 which is unlikely to be sufficient for an adequate therapeutic effect in this severe model of experimental PVR. In the human eye the time interval between the primary trauma and the occurrence of PVR varies according to the type of trauma involved.…”

Section: Discussionmentioning

confidence: 99%

An intravitreal biodegradable sustained release naproxen and 5-fluorouracil system for the treatment of experimental post-traumatic proliferative vitreoretinopathy

Cardillo

2004

British Journal of Ophthalmology

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Background/aims: To determine the potential of an intravitreal sustained release naproxen and 5-fluorouracil (NA/ 5-FU) codrug for the treatment of experimental proliferative vitreoretinopathy (PVR) in a model for trauma associated tractional retinal detachment (TRD). Methods: Sustained release pellets were prepared by covalently linking naproxen to 5-fluorouracil. Drug release was tested in vitro and toxic effects were evaluated by electroretinography and light microscopy. Traumatic PVR was induced in pigmented rabbits by performing a scleral laceration, followed by repair and intravitreal injection of 0.4 ml of autologous blood. Thirty six eyes were treated with a sustained release implant containing 1.5 mg NA/5-FU as a codrug and 36 control eyes were submitted to surgery alone. Eyes were evaluated for TRD by serial indirect ophthalmoscope examination at different time points followed by postmortem fundus evaluation of the enucleated eye Results: The NA/5-FU pellets were found to provide linear release of 5-FU and naproxen over the 30 day duration of the in vitro release test. Both the severity of PVR grade and the percentage of eyes with moderate or worse tractional detachment were significantly lower in eyes treated with the codrug pellet. There were no drug related toxic effects evident on histopathological or electroretinograph examination of eyes containing the NA/5-FU pellet. Conclusions: The results suggest that this NA/5-FU codrug device effectively inhibits the progression of PVR in a rabbit trauma model that closely resembles PVR in humans. Additional studies to add knowledge to these initial findings and to clarify the potential of the codrug device for the treatment of human PVR are warranted.

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“…The prevention of cell retention in the vitreous and faster release of trapped material after PPV could be driving the differences in the resolution rate. 11,12 In addition, hyaluronate present in the vitreous inhibits macrophage phagocytosis, which may slow VH resolution. 6 It appears as though variability in the vitreous and cell response to hemorrhage may underpin differences in the resolution rate of a VH.…”

Section: Discussionmentioning

confidence: 99%

Effect of Lens Status on Diabetic Vitreous Hemorrhage Resolution

Zeng

Cabral

Ness

et al. 2023

Journal of VitreoRetinal Diseases

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Purpose: To determine the effect of lens status (pseudophakic vs phakic) on diabetic vitreous hemorrhage (VH) resolution time. Methods: Medical records were reviewed retrospectively for each case of diabetic VH until resolution, pars plana vitrectomy (PPV), or loss to follow-up. Univariate and multivariate Cox regression models were used to determine predictors of diabetic VH resolution time through estimated hazard ratios (HRs). Kaplan-Meier survival analysis compared differences in the resolution rate by lens status and other significant factors. Results: Overall, 243 eyes were included. Pseudophakia (HR, 1.76; 95% CI, 1.07-2.90; P = .03) and prior PPV (HR, 3.28; 95% CI, 1.77-6.07; P < .001) were significant factors for faster resolution. Pseudophakic eyes resolved in 5.5 months (median, 25.1 weeks; 95% CI, 19.3-31.0) and phakic eyes in 10 months (median, 43.0 weeks; 95% CI, 36.0-50.0) ( P = .001). More pseudophakic eyes than phakic eyes resolved without PPV (44.2% vs 24.8%) ( P = .001). Eyes without prior PPV resolved in 9.5 months (median, 41.0 weeks; 95% CI, 35.7-46.3) compared with 5 months (median, 22.3 weeks; 95% CI, 9.8-34.8) in vitrectomized eyes ( P < .001). Age, treatment with antivascular endothelial growth factor injections or panretinal photocoagulation, intraocular pressure medications, and glaucoma history were not significant predictors. Conclusions: Diabetic VH resolved almost twice as fast in pseudophakic eyes than in phakic eyes. Eyes with a history of PPV resolved 3 times quicker than those without PPV. A better understanding of VH resolution can help personalize the decision on when to proceed with PPV.

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Effects of vitrectomy and phakectomy on the drainage of the vitreous compartment

Cited by 7 publications

References 9 publications

Controlled Drug Release from an Ocular Implant: An Evaluation Using Dynamic Three-Dimensional Magnetic Resonance Imaging

Controlled Drug Release from an Ocular Implant: An Evaluation Using Dynamic Three-Dimensional Magnetic Resonance Imaging

An intravitreal biodegradable sustained release naproxen and 5-fluorouracil system for the treatment of experimental post-traumatic proliferative vitreoretinopathy

Effect of Lens Status on Diabetic Vitreous Hemorrhage Resolution

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