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Many studies have shown that the presence of 1,25-dihydroxyvitamin D3 in the eye is able to modulate inflammatory responses. In fact, it has been demonstrated that topical administration of vitamin D3 inhibits Langerhans cells migration from the central cornea, corneal neovascularization, and production of cytokines (i.e., interleukin-1-6-8) in experimental animals. Moreover, both in vitro and in vivo studies have demonstrated that vitamin D is a potent inhibitor of retinal neovascularization. It has been shown that calcitriol, the biologically active form of vitamin D, inhibits angiogenesis both in cultured endothelial cells and in retinas from guinea pigs with retinoblastoma or oxygen-induced ischemic retinopathy. In addition, it seems that this compound is able to prevent the progression from early to neovascular age-related macular degeneration (AMD) and, at the same time, to down-regulate the characteristic inflammatory cascade at the retinal pigment epithelium-choroid interface due to its anti-inflammatory and immunomodulatory capabilities. Furthermore, 1,25-dihydroxyvitamin D3 and its analogue, 2-methylene-19-nor-1,25-dihydroxyvitamin D3, are able to modulate intraocular pressure (IOP) through gene expression. Several studies have suggested a role in glaucoma and diabetic retinopathy therapies for vitamin D3. In conclusion, this review summarizes our current knowledge on the potential use of vitamin D3 in the protection and treatment of ocular diseases in ophthalmology.

Curcumin (diferuloylmethane) is the main curcuminoid of the popular Indian spice turmeric (Curcuma longa). In the last 50 years, in vitro and in vivo experiments supported the main role of polyphenols and curcumin for the prevention and treatment of many different inflammatory diseases and tumors.The anti-inflammatory, antioxidant, and antitumor properties of curcumin are due to different cellular mechanisms: this compound, in fact, produces different responses in different cell types. Unfortunately, because of its low solubility and oral bioavailability, the biomedical potential of curcumin is not easy to exploit; for this reason more attention has been given to nanoparticles and liposomes, which are able to improve curcumin's bioavailability. Pharmacologically, curcumin does not show any dose-limiting toxicity when it is administered at doses of up to 8 g/day for three months. It has been demonstrated that curcumin has beneficial effects on several ocular diseases, such as chronic anterior uveitis, diabetic retinopathy, glaucoma, age-related macular degeneration, and dry eye syndrome. The purpose of this review is to report what has so far been elucidated about curcumin properties and its potential use in ophthalmology., (Georg Thieme Verlag KG Stuttgart · New York.)

The majority of ocular pathologies originate from a functional deterioration of intraocular tissues. This age-related deterioration often occurs as a result of changes within the eye. There is growing interest in the role of natural or synthetic compounds, such as carnitine, for blocking, or slowing, the progress of this deterioration. L-carnitine and its derivatives are involved in numerous physiological reactions, including sugar aerobic metabolism, oxidative phosphorylation, fatty acid oxidation and osmosis. While carnitine levels in human ocular tissue are unknown, animal studies indicate that carnitine is differentially distributed within the eye with the highest concentrations reported in the iris, ciliary body and the choroid-retina. In patients with age-related macular degeneration (AMD), acetyl-L-carnitine improved four parameters of visual function, including visual field mean defect, visual acuity, foveal sensitivity and ocular fundus alterations. L-carnitine has also demonstrated antioxidant properties in animal models of oxidative damage. This article reviews the potential use of L-carnitine and its derivatives in age-related ocular pathologies, such as AMD, cataract, glaucoma and dry eye syndrome.

L-carnitine has a wide-ranging role in several physiological processes, but perhaps most significantly in long-chain fatty acid oxidation in the mitochondrial matrix. Osmolytic (or osmoprotective) properties have also been suggested for the compound. Importantly, the ability of L-carnitine to improve insulin sensitivity in insulin-resistant diabetic patients may, together with the agent's antioxidant and antiapoptotic activity, provide some degree of protection against the progression of diabetic retinopathy. L-carnitine may also protect against the deleterious effects of ocular ischaemic syndrome, and, indeed, acetyl-L-carnitine has been shown to significantly improve retinal damage and visual acuity in patients with monolateral or bilateral retinal artery occlusion. The antioxidant, antiapoptotic and osmolytic properties of L-carnitine also suggest that this agent may have valuable clinical utility in neurotrophic keratopathy and bullous keratopathy. Thus, further detailed investigation of the important clinical potential of L-carnitine in various ocular conditions (e.g. diabetic retinopathy, ocular ischaemic syndrome, neurotrophic keratopathy and bullous keratopathy) that occur secondary to systemic diseases is now clearly warranted.

L-carnitine plays a role in physiological reactions throughout the body, including sugar aerobic metabolism, oxidative phosphorylation and, most importantly, fatty acid oxidation. In addition, L-carnitine has antiapoptotic, antioxidative and osmolytic properties, which may be useful in the treatment of ocular pathologies (e.g. retinitis pigmentosa [RP] and keratoconus), in corneal tissue repair and in ophthalmic procedures (e.g. photorefractive keratectomy and laser-assisted subepithelial keratectomy [LASEK]). Preliminary studies have suggested that Lcarnitine supplementation may be useful in patients with RP. Although studies are warranted to ascertain the benefit of L-carnitine in the LASEK procedure, potentially it could be used instead of alcohol to facilitate epithelial detachment and as a hypo-osmotic solution in the fluid filler used in therapeutic photoablation. Furthermore, its antiapoptotic properties may improve cellular migration, proliferation and adhesion of keratocytes, epithelial cells and endothelial cells, which may be useful in the corneal repair process. Similarly, L-carnitine in high concentrations may prove useful in cross-linking parasurgical treatment of keratoconus, owing to its osmolytic and non-cytotoxic properties. [ABSTRACT FROM AUTHOR]