Vision, RetinaVariations in cone populations for red–green color vision examined by analysis of mRNAHagstrom, Stephanie A.2; Neitz, Jay1; Neitz, Maureen1,3Author Information 1Department of Cell Biology, Neurobiology and Anatomy and Department of Ophthalmology, Medical College of Wisconsin, 925 N. 87th Street, Milwaukee, Wisconsin 53226-4812, USA. 2Present address Harvard Medical School, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, 243 Charles Street, Boston, Massachusetts 02114-2096, USA. 3Corresponding Author: Maureen Neitz ACKNOWLEDGEMENTS: This work was supported by NEI Grants EY09303, EY09620, Core Grant EY01931, an RPB Career Development Award and an RPB James S. Adams Scholar Award to M. N. and an unrestricted RPB award to Ophthalmology at MCW. Website publication 20 June 1998 Received 18 March 1998; accepted 5 April 1998 NeuroReport: June 22, 1998 - Volume 9 - Issue 9 - p 1963-1967 Buy Abstract IN the central human retina, there are estimated to be nearly two L cone photoreceptors for each M cone. The extent to which this value varies across individuals is unclear and little is known about how the M:L cone ratio might change with retinal location. To address these questions, the ratio of M:L cone pigment mRNA was examined at different locations. For patches of central retina, the average M:L ratio was about 2:3 which decreased to about 1:3 for patches 40°eccentric. There were also large individual differences among the 23 eyes examined. The extremes differed in central M:L mRNA ratio by a factor of > 3. The measured differences in mRNA ratio are proposed to reflect differences in photo-receptor ratio. Such variations provide unique opportunities for understanding how the neural circuitry for color vision is affected by changes in cone ratio. © Lippincott-Raven Publishers.