Purchase this article with an account.
T. Ho; Enzymatic Induction of Posterior Vitreous Detachment (PVD) in Form-deprivation Myopia (FDM) Chick Eyes as a Model to Investigate Vitreoretinal Interface in Peripheral Retinal Degenerations in Myopia . Invest. Ophthalmol. Vis. Sci. 2003;44(13):1991.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose. To investigate the ability of dispase and plasmin to induce a PVD in form-deprivation chick eyes. Methods. Dispase or plasmin (control = PBS) was injected into the vitreous of 28 days old form-deprivation chick eyes; incubated at 37o C for 120 minutes. The globes were hemi-sected and the extent of a PVD was graded as complete, partial or none. Biomicroscopic examination, light microscopy were performed to determine the ultrastructure of the vitreoretinal interface, retina and choroid. The cell viability and structural integrity of the treated retina was estimated by measuring the elastic constant (k) and maximal retinal stretching before fracture (s) in the equatorial area of the eyes. Results. A partial or complete PVD was present in 86%, 78% and 42% of eyes in dispase-treated , plasmin and control group in FDM eyes. In non-FDM eyes, PVD was present in 66%, 64% and 31% of eyes respectively. Cell viability, (k) and (s) were measured for dispase-treated, plasmin-treated and control eyes in FDM eyes (93.8 ± 2.1%, 93.6 ± 1.9% vs. 94.2 ± 3.2%, 1.3 ± 0.3, 1.3 ± 0.5% vs 1.4 ± 0.2 N.m-1, 2.1 ± 0.1, 2.6 ± 0.3 vs 2.0 ± 0.2). In non-FDM eyes, cell viability, (k) and (s) were measured for dispase-treated, plasmin-treated and control eyes (96.8 ± 1.6%, 96.6 ± 1.3% vs. 97.6 ± 1.6%, 1.5 ± 0.5, 1.5 ± 0.6 vs 1.6 ± 0.4 N.m-1, 2.5 ± 0.2, 2.6 ± 0.3 vs 2.4 ± 0.2). On light microscopic study, dispase selectively cleaved the attachment of the posterior hyaloid to the ILM while preserving the ultrastructure of the retina in both FDM and non-FDM eyes. Conclusions. PVD is more frequently found and easily induced in FDM eyes than in non-FDM eyes by dispase or plasmin intravitreal injection. The mechanical property measurements of retina in FDM eyes showed lower elasticity and more fragility than in non-FDM eyes. Dispase and plasmin are able to disrupt the attachment of the posterior hyaloid to the ILM in both FDM and non-FDM eyes safely. The equatorial enlargement of eyeball in FDM chick eyes may contribute to these effects. Our study probably provides a model to investigate the vitreoretinal interface and retinal abnormalities in peripheral retinal degenerations in myopia.
This PDF is available to Subscribers Only