Which condition involves loss of photoreceptors, especially in the fovea?

The condition that involves loss of photoreceptors, particularly in the fovea, is macular degeneration. This condition specifically affects the central part of the retina, known as the macula, which is crucial for high-acuity vision and color perception. In macular degeneration, the cells in this area deteriorate, leading to a progressive loss of vision in the central field, while peripheral vision may remain intact.

Cataracts involve the clouding of the lens of the eye, resulting in blurred vision, but they do not specifically affect the photoreceptors in the retina. Glaucoma is characterized by damage to the optic nerve often due to elevated intraocular pressure, which can lead to peripheral vision loss but does not involve the fovea directly. Presbyopia is an age-related condition that affects the eye's ability to focus on near objects due to changes in the lens, rather than damaging photoreceptors.

Thus, macular degeneration is the correct answer as it directly relates to the loss of photoreceptors in the fovea.