Refractive errors are the most common cause of visual impairment in the world. Multiple eye structures are involved in focusing of the light coming from the environment, but ultimately, the retina is the neural tissue that evaluates the quality of the focus and generates the signals that induce eye adjustment. However, the retinal signaling involved in defocus detection is not completely known. My research topic is based on understanding how distinct retinal circuits participate in defocus detection and how distinct neuromodulators contribute to its regulation.
Currently, I am studying the role of the retina in the development of myopia, a type of refractive error in which an irregular eyeball elongation causes the focal point of the eye to be located in front of the retina, making it difficult to focus distant objects. The retinal processing responsible of defocus detection involves the participation of different retinal pathways, in which the interaction between dopamine and GABA seems to be of great importance to reveal the mechanisms involved in the development of this visual dysfunction.

• (2024) Estay SF, Morales-Moraga C, Vielma AH, Palacios-Muñoz A, Chiu CQ, and Chávez AE. Non-canonical type 1 cannabinoid receptor signaling regulates night visual processing in the inner rat retina. iScience. 27(6):109920. doi: 10.1016/j.isci.2024.109920. eCollection 2024.
• (2024) Tapia F, Peñaloza V, Silva-Olivares F, Sotomayor-Zárate R, Schmachtenberg O, Vielma AH. Glucagon increases retinal rod bipolar cell inhibition through a D1 dopamine receptor-dependent pathway that is altered after lens-defocus treatment in mice. Invest Ophthalmol Vis Sci. 65(1):46. doi: 10.1167/iovs.65.1.46.
• (2020) Vielma AH, Tapia F, Alcaíno A, Fuenzalida M, Schmachtenberg O, Chávez AE. Cannabinoid signaling selectively modulates GABAergic inhibitory input to OFF bipolar cells in rat retina. Invest Ophthalmol Vis Sci. 61(3):3. doi: 10.1167/iovs.61.3.3.
• (2016) Vielma AH, Schmachtenberg O. Electrophysiological fingerprints of OFF bipolar cells in rat retina. Sci Rep. (6):30259. doi: 10.1038/srep30259.
• (2015) Elgueta C, Vielma AH, Palacios AG, Schmachtenberg O. Acetylcholine induces GABA release onto rod bipolar cells through heteromeric nicotinic receptors expressed in A17 amacrine cells. Front Cell Neurosci. 9(6). eCollection 2015. doi: 10.3389/fncel.2015.00006.