Which of the following has the largest retinal image size when uncorrected?

• A. Uncorrected axial myope
• B. Uncorrected axial hyperope
• C. Uncorrected refractive myope
• D. Uncorrected refractive hyperope

Answer: (A)

The size of the retinal image for a given external object depends on the distance from the eye’s nodal point to the retina (the effective focal length) and the angular size of the object. In axial myopia, the eye is longer than normal, so the retina sits farther back from the lens system. For the same object, that greater distance means a larger linear image is projected onto the retina. An uncorrected axial hyperope has a shorter eye, placing the retina closer to the optical system, which yields a smaller retinal image for the same distant object. If the refractive error is due to power (not length) changes but the axial length is near normal, the retina isn’t moved as far from the nodal point, so the retinal image isn’t as magnified as in axial myopia. Thus, among the uncorrected conditions, the largest retinal image size comes from an uncorrected axial myope.