262 Medical Terminology: Mastering the Basics Presbyopia Presbyopia (PRĔZ-bē-ŌP-ē-ă) is a condition in which the lens of the eye gradually loses its elasticity, or the ability to change its shape, making it dif- ficult to see objects up close. Presbyopia occurs naturally with age thus, it is often called the “aging eye condition.” As the lens of the eye becomes less flexible, it no longer can change shape to focus on images at close range. As a result, objects appear out of focus. The Ear Infection or disease of the ear can affect hearing, balance, or both. Certain conditions of the ear can cause hearing disorders or deafness. We will take a brief look at some of the more common conditions. Ménière’s Disease Ménière’s (mĕn-YĔRZ) disease is a chronic inner-ear disorder that affects balance and hearing (Figure 6.7). The inner ear contains semicircular canals, small fluid-filled tubes that help your body maintain its position and bal- ance. Every time you move your head, the fluid within the canals stimulates tiny hairs lining each canal. These hairs interpret the movement of the fluid and transmit neural impulses to the brain. The cause of Ménière’s disease is unknown. Symptoms include dizziness or a sensation of spinning called vertigo (VĔR-tĭ-gō or vĕr-TĒ-gō) tinnitus (TĬN-ĭ-tŭs or tĭ-NĪ-tŭs), commonly known as “ringing in the ears“ pressure within the ear and hearing loss. Figure 6.7 Ménière’s disease Endolymphatic sac (Regulates fluid volume and pressure and immune response of the inner ear) Hearing and balance nerve Backed-up fluid leads to swelling and pressure. Distorted information travels to brain. A. Healthy inner ear B. Ménière’s disease Balance canal Swelling distorts balance information. Swelling distorts sound information. Hearing canal