"That is good news!" Samantha exclaimed. "I finished graduate school last year, and I haven't had so much reading and computer work to do; it's been a lot easier on my eyes. Could that help explain why my vision hasn't gotten any worse?" "Yes!" replied Dr. Thompson. "Normally, the eye should be almost perfectly spherical. When you do lot of reading or other work that requires focus on close objects, the lens of the eye has to change shape. It actually starts to bulge into the posterior chamber. This bulging increases pressure in the posterior chamber and over time that can start to stretch the eye out and cause it to become longer. Usually nearsightedness, or myopia, is caused by an eyeball that has become too long."

3. Based on the description given by Dr. Thompson, which eye in Figure 2 below is currently accommodating for viewing a close object, Eye A or Eye B? Explain your answer.

"Why does an eye that has become too long cause distant vision to be blurry?" Samantha asked. "Light rays are bent, or refracted, when they pass through curved surfaces. Here's a diagram that shows how this works, Samantha." Dr. Thompson handed her Figure 3:

4. According to Figure 3, how does concave surface differ from a convex surface?