Photoreceptor toxicity caused by SRH occurs at least in part by apoptosis and is associated with iron migration to the photoreceptor layer. Treatment with IVTA reduced photoreceptor loss and apoptosis, indicating a neuroprotective action. Therapies to target SRH may augment anti-VEGF treatments in exudative age-related macular degeneration and other diseases of choroidal neovascularization.

Corneal cross-linking with ultraviolet-A and riboflavin results in a statistically significant reduction in corneal permeability. These findings suggest that dosing of topical medications may need to be increased in eyes with a history of CXL to achieve expected therapeutic effects, and they may have implications for the long-term health of the cornea.

Nonenzymatic cross-link density in the cornea can be significantly increased by treatment with methylglyoxal. Porcine cornea showed a nonlinear reduction in solute permeability and specific hydraulic conductivity with increasing cross-link density. This model suggests that age-related nonenzymatic cross-link accumulation can have a substantial impact on corneal permeability.

The purpose of this study was to assess fundamental differences between the mechanics of the posterior sclera in paired eyes using uniaxial and whole globe inflation testing, with an emphasis on the relationship between testing conditions and observed tissue behavior. Twenty porcine eyes, consisting of matched pairs from 10 pigs, were used in this study. Within pairs, one eye was tested with 10 cycles of globe pressurization to 150 mmHg (~10x normal IOP) while biaxial strains were tracked via an optical system at the posterior sclera. An excised posterior strip from the second eye was subjected to traditional uniaxial testing in which mechanical hysteresis was recorded from 10 cycles to a peak stress of 0.13 MPa (roughly equivalent to the circumferential wall stress produced by an IOP of 150 mmHg under the thin-walled pressure vessel assumption). For approximately equivalent loads, peak strains were more than twice as high in uniaxial tests than in inflation tests. Different trends in the load-deformation plots were seen between the tests, including an extended “toe” region in the uniaxial test, a generally steeper curve in the inflation tests, and reduced variability in the inflation tests. The unique opportunity of being able to mechanically load a whole globe under near physiologic conditions alongside a standard uniaxially tested specimen reveals the effects of testing artifacts relevant to most uniaxially tested soft tissues. Whole globe inflation offers testing conditions that significantly alter load-deformation behavior relative to uniaxial testing; consequently, laboratory studies of interventions or conditions that alter scleral mechanics may greatly benefit from these findings.

The identification of biomaterials that are well tolerated in the eye is important for the development of new ocular drug delivery devices and implants, and the application of micro- and nanoengineered devices to biomedical treatments is predicated on the long-term preservation within the target organ or tissue of the very small functional design elements. This study assesses the ocular tolerance and durability of micro- and nanostructured biopolymer thin films injected or implanted into the rabbit eye. Structured poly(caprolactone) (PCL) thin films were placed in adult rabbit eyes for survival studies, with serial ophthalmic examinations over 6 months. Morphologic abnormalities and device/tissue reactions were evaluated by histologic studies, and scanning electron microscopy (SEM) of films was used to determine the structural integrity. Structured PCL thin films (20- to 40-μm thick) were constructed to design specifications with 50-μm linear microgrooves or arrays of nanopores with ~30-nm diameters. After up to 9 months of ocular residency, SEM on devices retrieved from the eye showed preservation of micro- and nanostructural features. In ocular safety evaluations carried out over 6 months, serial examinations in 18 implanted eyes showed no evidence of chronic inflammation, cataractogenesis, or retinal toxicity. Postoperative ocular inflammation was seen in 67% of eyes for 1 week, and persistent corneal edema occurred in 1 eye. Histology revealed no ocular inflammation or morphologic abnormalities of ocular tissues. Thin-film/tissue responses such as cellular reaction, fibrosis, or surface biodeposits were not seen. Micro- and nanostructured PCL thin films exhibited acceptable ocular tolerance and maintained the structural integrity of design features while residing in the eye. Thin-film micro- and nanostructured PCL appears to be a feasible biomaterial for intraocular therapeutic applications.