Ocular structure

Topical application is the most common route of administration for ophthalmic drugs. Advantages include convenience, simplicity, noninvasive nature, and the ability of the patient to self-administer. Because of blood and aqueous losses of drug, topical medications typically do not penetrate in useful concentrations to posterior ocular structures and therefore are of no therapeutic benefit for diseases of the retina, optic nerve, and other posterior segment structures. 

Moderate to severe - Use higher strengths for moderate to severe inflammations. In difficult cases of anterior segment eye disease, systemic therapy may be required. When deeper ocular structures are involved, use systemic therapy (prednisolone). 

Acute epithelial herpes simplex keratitis (dendritic keratitis) fungal diseases of ocular structures vaccinia, varicella and most other viral diseases of the cornea and conjunctiva ocular tuberculosis hypersensitivity after uncomplicated removal of a superficial corneal foreign body mycobacterial eye infection acute, purulent, untreated eye infections that may be masked or enhanced by the presence of steroids. 

Hypersensitivity to any component of these products epithelial herpes simplex keratitis (dendritic keratitis) vaccinia varicella mycobacterial infections of the eye fungal diseases of the ocular structure use of steroid combinations after uncomplicated removal of a corneal foreign body. 

Contraindications Hypersensitivity to ciprofloxacin or other quinolones for ophthalmic administration vaccinia, varicella, epithelial herpes simplex, keratitis, mycobacterial infection, fungal disease of ocular structure, use after uncomplicated removal of a foreign body... 

Chemicals are omnipresent in our world today. Chemical risk is a permanent issue in our everyday environment, obviously on work premises, and may also be caused by different circumstances of chemical assaults. Among all chemical accidents, eye projections are a specific issue because of the vulnerability of ocular structures and also because of the risk of major functional after-effects. Chemical Abstracts Service (CAS) is a division of the American Chemical Society. This International database of the American Chemical Society is a worldwide reference registering... 

Ocular drugs, cosmetics or all chemicals, which can come in contact with the eye carry the potential of harming various ocular structures. Thus, their possible toxic effects on ocular structures must be evaluated in tests before use in humans. 

In addition to variables in clinical signs and symptoms and the ability to penetrate the ocular structures, the derivative of a steroid base also seems to influence its anti-inflammatory efficacy. Using a rabbit corneal model, it was demonstrated that acetate and alcohol derivatives are more effective than the phosphate derivative in suppressing corneal inflammation both in the presence and absence of corneal epithelium (see Table 12-1). The mechanism by which a derivative affects the anti-inflammatory activity of a steroid base applied topically to the eye is not known, but some data seem to indicate that receptor binding or metabolism plays a role in the observed antiinflammatory and ocular hypertensive effects. 

Krishna N, Mitchell B. Polyvinyl alcohol as an ophthalmic vehicle effect on ocular structures. Am J Ophthalmol 1965 59 ... 

Because the eye is highly accessible to clinical examination, drugs that cause a deposit or change to an ocular structure can be readily observed, often before there is any functional change noted by the pafient.Thus, many system-ically administered drugs can cause adverse ocular effects, nearly all structures of the eye are vulnerable, and eye care professionals must be vigilant to detect such changes. 

This chapter considers primarily those prescription drugs that have been frequently implicated in OADRs. Some of the common OADRs noted in vitamin and herbal supplements are listed toward the end of the chapter. Clinically important drug effects are categorized in the ocular structure or fimction affected rather than in specific drug classes. A comprehensive review chart at the end of the chapter serves as a reference and study guide (Appendix 35-1). Recommendations for eye care practitioners for reporting suspected drug-induced ocular adverse effects are reviewed. 

All routes of drug administration can affect ocular structures and functions. OADRs have been associated with topical ophthalmic administrations as well as local injections. Systemically, oral drug administration has been implicated most frequently in the development of OADRs. However, parenteral as well as inhaled or nasally applied drugs have also produced OADRs. Topical application to the skin, particularly if it is abraded or burned, may result in sufficient systemic absorption to lead to ocular side effects. Dermatologic use of antibiotics has resulted in ocular hypersensitivity reactions. 

Allergic reactions are not infrequent and, more often than not, are unpredictable and sometimes difficult to manage. The skin is the most commonly involved tissue. Reactions can range from a mild rash to exfoliative dermatitis and erythema multiforme. Ocular structures most commonly affected are the eyelids and the conjunctiva. 

Early in the 1930s, an untested eyelash dye containing i-pheylenediamine (Lash Lure) was brought onto the market in the United States. This product (as well as a number of similar products) rapidly demonstrated that it could sensitize the external ocular structures, leading to corneal ulceration with loss of vision and at least one fatality. 

The complication risk in Type-I diabetes is related not only to duration of the disease but also to the degree of glycaemic control, blood pressure and genetic susceptibility (Hanssen, 1991). The most frequent chronic complication in Type-I diabetes is diabetic background retinopathy, with a near-100% occurrence rate after 15 years diabetes duration. Manifestations of diabetes, however, can be found in all ocular structures (Table 1). 

Hammeshige S, Potts AM. The penetration of cortisone and hydrocortisone into ocular structures. Am J Ophthalmol 1955 40 3211-3215. 

Figure 8 Representative autoradiographic images taken from cross sections of rabbit eyes injected intravitreously with radiolabeled INS37217 (3H-INS37217 at 3 mg per eye) showing the distribution of radiolabeled signal in various ocular structures at the postinjection time points indicated. Radioactivity from INS37217 or its metabolites is distributed throughout the entire vitreous within 15 minutes and is largely absent by 48 hours.

Ocular administration of 1% calcium gluconate solutions every 4-6 hours has been utilized for 24-48 hours but is of unproved efficacy over irrigation with saline or water. Higher concentrations of calcium gluconate may worsen corrosive injury to ocular structures. Ophthalmology consultation should be obtained. 

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