Purchase this article with an account.
W.J. Foster, A.H. Ali, N. Ravi; Sol-Gel Systems as Vitreous Substitutes . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2975.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To develop alternatives to silicon oil and perflurocarbon liquids for repair of complex retinal detachments. We seek to create an artificial version of the formed, juvenile vitreous using newly developed polymeric sol-gel systems. This would avoid issues related to patient positioning and known toxicity of current materials as well as provide better treatment of inferior tears. By selecting such systems, we also can avoid exposure of the intra-ocular tissues to toxic monomers and the thermal energy present in exothermic in vivo polymerization reactions. Unique to our system is the ability to induce swelling of the polymer after cross-linking (formation of the gel) and thus tamponade the retinal tear. Methods: In this proof-of-principle series of experiments, we have utilized our sol-gel system [H.Aliyar, P.Hamilton, N.Ravi, Investigation On In-situ Endocapsular Gelation Of Copolyacrylamides, ARVO 2002 B384], allowed cross-linking in vivo, and induced swelling of the gel through normal hydration in the vitreous cavity in human cadaver eyes. We performed a pneumatic vitrectomy and then instilled the polymer into the vitreous cavity through a pars-plana approach. The eye was then maintained oriented upward (as if the patient were lying supine). After the gel had polymerized and swollen, the globes were examined. Results: We have successfully implemented the above protocol in cadavaric eyes. The hydrated gel was formed and noted to have vitreous-like consistency. Gels of similar composition, formed in vitro, have an elastic modulus of 100-150 Pa and contain more than 98% water. In performing the procedure, we have developed experience that will guide animal studies as well as trials of other sol-gel systems. Conclusions: Spontaneously forming reversible sol-gel systems are a reasonable alternative to current vitreous substitutes. By changing paradigm from a liquid or gas to a formed artificial vitreous that tamponades the retina against the RPE, we may avoid the limitations of current substitutes such as the need for face-down positioning, need for a second surgery to remove oil, glaucoma, and toxicity. Further work is needed to evaluate toxicity and the risk of complications.
This PDF is available to Subscribers Only