COMPLEMENTARY CONE FIELDS OF THE RABBIT RETINA

Purpose. Complementary cone fields have been considered a unique featu re of the mouse retina. In an attempt to map the arrangement of the co lor-specific cones in other mammals, the authors investigated the rabb it, a commonly used experimental animal for vision research. Methods. For the identification of the different cone types immunocytochemistry was used with two monoclonal antibodies, each specific to the middle- to long-wave (red-green) and short-wave (blue) sensitive visual pigme nts, respectively. Results. The major part of the retinal surface, inc luding the visual streak, exhibited a dominance of M (middle-wave sens itive) cones (6 to 13,000/mm(2)) versus S (short-wave sensitive) cones (1 to 2,500/mm(2)). In contrast, the lower 5% to 6% of the total reti nal area showed a complete lack of green cones and a high density of b lue cones (11,000/mm(2)). The authors designate this crescent-like are a the blue streak of the rabbit retina. Conclusion. In addition to the visual streak primarily abundant in green cones, there is a specializ ed area of the rabbit retina that is densely and exclusively populated with blue cones. Although the relative extension of this peculiar con e field is considerably smaller than the S-field of the mouse retina, its position is similar in that it occupies the lowermost part of the retina. The functional implication of this area is unknown.