CHAPTER I

INTRODUCTION

Doctors are independent primary health care providers who examine, diagnose,

treat, and manage diseases and disorders of the visual system, the eye, and associated

structures as well as diagnose related systemic conditions, such as optic neuritis and

cataract.

Optic neuritis (ON) is Optic neuritis is defined as inflammation of the optic nerve

(Thurtell, 2012). Inflammatory optic neuropathy (optic neuritis) may be due to a variety of

causes, but the most common is demyelinative disease (Vaughan and Asburys, 2007). In

most parts of the world acute demyelinating optic neuritis is the most common cause of

unilateral painful visual loss in a young adult. Optic neuritis is the presenting feature of MS

in 15 to 20 percent of patients and occurs in 50 percent at some time during the course of

their illness. The term optic neuritis is sometimes applied to other inflammatory and

infectious conditions affecting the optic nerve.

Patients with ON experience rapidly developing impairment of vision in 1 eye or,

less commonly, both eyes during an acute attack (Atkins, 2006). Dyschromatopsia (change

in color perception) in the affected eye occasionally may be more prominent than the

decreased vision (Flanagan, 2006; Zele, 2004). In nearly all cases, the visual changes are

associated with a retro-orbital or ocular pain, usually exacerbated by eye movement. The

pain may precede the visual loss. Since ON can herald a more diffuse demyelinating

disease, care should be taken in making an accurate diagnosis, and careful consideration

given to treatment options, particularly as other causes of ON not related to MS require

quite different management.

Cataract is the major cause of blindness in the world and the most prevalent ocular

disease. In the United States, cataracts are the most frequently cited self-reported cause of

visual impairment and the third leading cause of preventable blindness. Visual disability

from cataracts accounts for more than 8 million physician office visits per year.

When the disability from cataract affects or alters an individual's activities of daily

living, surgical lens removal with intraocular lens implantation is generally the preferred

means of treating the functional limitations. The initial diagnosis of cataract may be made

by any of a number of providers, such as a primary care physician, optometrist, or

ophthalmologist. The patient's decision to proceed with cataract surgery to decrease

disability involves consultation with an optometrist and/or ophthalmologist. Often the

patient has a long-term relationship with the optometrist who is the patient's primary eye

care provider before a cataract develops.