Engineering the crystalline lens with a biodegradable or non-degradable scaffold

Both a biodegradable hyaluronic acid (HA) and a nondegradable polymeric gel were evaluated as scaffolds for tissue engineering the lens in Dutch Belt pigmented and New Zealand white rabbits. Following removal of the crystalline lens through a 2 mm capsulorhexis, a collagen patch or a silicone plug was placed in the capsule bag to seal the capsulotomy. In Part I, a cross-linked HA or cohesive solution of HA was injected into the capsule bag. In Part II, a synthetic polymer (SP) was injected into the capsular bag of one eye and HA followed by SP (HA/SP) was injected into the capsule bag of the opposite eye. At 3 months focal Nd:YAG laser photocoagulation was performed in an attempt to remove some retained HA gel in one eye. Overall the regenerated lenses of the HA gel groups were spherical with excellent cortical structure and clarity and a spherical nucleus of condensed HA gel. In the one eye treated with focal photocoagulation, partial clearing of the retained HA gel was noted. In the SP and HA/SP eyes, lens regrowth around the polymer was generally clear in the anterior and peripheral capsule bag and more opacified posterior to the polymeric scaffold. In summary, naturally regenerating lens tissue was directed to grow in a more normal, regular pattern by providing a biodegradable hyaluronic acid scaffold or a nondegradable polymeric optical scaffold.