Retina drugs affecting

Tamoxifen (also see text Drugs Affecting the Retina) Whorl-like opacities (uncommon)... 

We recently proposed a completely electronic model for the excitability of nerve membranes that is based on the assumption of electron-donating, electron-accepting, and electron-storing properties of macromolecules or of protein-lipid complexes which constitute the ionic channels of the nerve membrane (63). This model, which is based on simple physical concepts with easily defined parameters, reproduces the empirical Hodkgin-Huxley equations rather well and also explains how different types of drugs may work on nerves. The model is easily extended to other excitable complexes like the receptor protein complex at nerve synapses and the rodopsin molecules in the retina. Nor is it inconceivable to build a model for the function of smell that is based on electronic triggering of ionic channels which are affected by molecules adsorbed onto or dis-... 

Tight junctional complexes zonula occludens ) in the retinal pigment epithelium prevent the ready movement of antibiotics and other drugs from the blood to the retina and vitreous. The retina is a developmental derivative of the neural tube wall and can be viewed as a direct extension of the brain it is not surprising that the blood-retinal barrier somewhat resembles the blood-brain barrier in form and function. Experimental evidence has shown that histamine does not alter the vascular permeability of the retina but does affect that of all other ocular tissues. The retina closely resembles the brain with respect to this trait. 

Most of the damage to the eye caused by direct irradiation from the sun or artificial sources is from ultraviolet radiation. However, in the presence of a light-activated (photosensitized) diagnostic dye or drug, patients are in danger of enhanced ocular injury from ultraviolet and visible light. The extent to which a particular photosensitizer will affect the human cornea, lens, and/or retina in vivo depends upon ... 

Generally, pharmacological treatment of diseases in the eye is limited by special pharmacokinetic properties inherent in the anatomy of the eye. Diseases in the anterior segment of the eye are predominantly treated by local application of the active compound in the conjunctiva These drugs will diffuse into the eye to affect the vitreous body and the retina, but for practical purposes this mode of administration is less suitable for diseases in the posterior segment of the eye. The vitreous body is avascular, which implies that the treatment of diseases in and around this structure depends on intravitreal injection of the active compound. On the contrary, the retina is richly vascularized, but the access to this structure of drugs administered through the systemic circulation is... 

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