What landmark is located at the front edge of the retina and has a tooth-like appearance?

The ora serrata is indeed the landmark located at the front edge of the retina and is characterized by its unique tooth-like appearance. This area acts as a boundary where the sensory retina begins. The ora serrata marks the transition from the more peripheral regions of the retina, where the structure begins to change.

The fovea centralis is the part of the retina responsible for sharp central vision and contains a high density of cone photoreceptors, but it does not have the serrated or tooth-like appearance. The macula lutea is an area surrounding the fovea that is also critical for vision, especially in daylight conditions, but it does not feature the distinct serrated edge. The term "retinal layer" is too broad and does not refer to a specific anatomical landmark within the retina, lacking the distinctive morphological feature that defines the ora serrata. Thus, the ora serrata stands out as the correct answer due to its specific location and appearance.