CHAPTER 33

Ophthalmic Medications

Celtina K. Reinert, PharmD

LEARNING OBJECTIVES KEY TERMS AND DEFINITIONS After completing this chapter, you should be able to Aqueous humor — the thick, watery fl uid located between the 1. Review the anatomy and physiology of the eye cornea and the lens. 2. Describe glaucoma and the most commonly used treatment approaches Cataract — an eye condition in 3. Describe the causes and symptoms of conjunctivitis and treatment options which a clouding of the lens occurs. Conjunctiva— the tissue around 4. Identify common causes of blindness the eye. 5. Identify medications used in the eye including their dosage forms, therapeutic Conjunctivitis — infl ammation effects, most common side effects, and mechanisms of action of the conjunctiva. Cornea — clear covering over the front of the eye. he eye is the organ for sight. Many things can affect the eye including diabetes, Cycloplegia— paralysis of the muscle that holds the lens in place. T trauma, vision problems, and allergies. Some of these can be improved with Causes a loss of accommodation or treatments including surgery and medications used in the eye. This chapter will ability to focus the lens. discuss these and how ophthalmic medications are used. Diplopia— double vision. Glaucoma — eye condition that can result from increased pressure in the eye and can cause nerve damage. Intraocular pressure (IOP) — measurement of pressure in the eye, usually < 21 mm Hg. Increases in IOP can lead to glaucoma or blindness. Iris— the colored part of the eye. Macula— focal point on the retina that allows for clear, sharp vision especially when focusing on tasks straight ahead. Miosis — constriction of the pupil, allowing less light into the eye. Mydriasis— enlargement of the pupil, allowing more light into the eye. Commonly done for some eye examination procedures. Ocular hypertension— an increase in intraocular pressure, which may lead to glaucoma in some patients. PART 12

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Pupil— dark space in the middle Anatomy of the Eye of the iris that appears black. It widens and narrows to allow varying amounts of light into The eye functions as our organ for sight. Light enters the eye, passing through the trans- the eye. parent cornea , enters the pupil , an open space in the center of the iris , and is refracted Retina — lining in the back of the through the lens and onto the retina . The retina is attached to the inside back of the eyeball that allows light messages to eyeball and transmits messages to the optic nerve. The optic nerve carries these light be transmitted to the optic nerve and messages to the brain where they are translated into pictures of what is being seen. These then the brain. structures are illustrated in Figure 33-1. Sclera— white, outer part of the Many problems can occur in this complicated organ and communication process. eyeball. Blurry vision is a common occurrence that can be from many causes including vision changes or some medications. One of these vision changes is myopia, or nearsighted- ness, where the light is focused through the lens to a place in front of the retina instead of on it. This means the person can see objects close up but those at a distance are blurry. The opposite of myopia is farsightedness, where patients can see things far away but items up close are blurry. This occurs when the lens focuses items beyond the back of the retina. Both of these conditions can be improved by corrective lenses and sometimes corrective surgery. Diplopia is double vision, which can occur due to various reasons (some minor and some serious). Treatment will depend on the cause. Another common eye condition is presbyopia, where the eye gradually loses the ability to focus on close- up objects. Presbyopia usually occurs as people age, starting in the 40s and gets worse until around age 60. A cataract is another relatively common eye condition, in which a clouding of the lens occurs as a person ages. As the lens clouds, there is usually a loss in vision. This development is commonly slow, occurring over many years with a gradual decline in vision. Often, this can be corrected with surgery. Glaucoma

CASE STUDY

Mrs. Griffen has recently been diagnosed with ocular hypertension in both eyes. She hasn ’t noticed any vision changes yet, but both of her parents had glaucoma and her mother went blind in her 80s.

Conjuctiva Retina Iris Macula

Cornea Pupil Lens Optic Sclera nerve

Figure 33-1. Anatomy of the eye.

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