What term describes difficulty with close work due to a decrease in the eye's ability to change focus?

The term that best describes difficulty with close work due to a decrease in the eye's ability to change focus is presbyopia. This condition typically occurs as people age, usually starting in their 40s or 50s, when the lens of the eye loses elasticity, making it harder to focus on nearby objects. This loss of flexibility in the lens affects the ability to accommodate, or adjust focus, leading to challenges with tasks such as reading or sewing.

Amblyopia refers to a vision development disorder where one eye fails to achieve normal visual acuity, which does not specifically relate to difficulties with close work. Cataracts involve the clouding of the eye's lens, leading to blurred vision but are not exclusively linked to problems focusing on near tasks. Conjunctivitis is an inflammation of the conjunctiva, usually resulting in red, itchy, or watery eyes, and does not affect the ability to change focus. Therefore, presbyopia is the most appropriate term for the difficulty described.