Abstract: Erythrocyte tropomodulin (E-Tmod) is a tropomyosin(TM) binding protein and actin capping protein at the point end of the filaments. It is part of a molecular ruler that plays an important role in generating short actin protofilaments critical for the integrity of cell membrane. Previously we created a knockout mouse model in which lacZ was knocked-in downstream of the E1 promoter to report the expression of full length E-Tmod^+/lacZ and E-Tmod^-/-. Here we utilize heterozygous (E-Tmod^+/lacZ) and homozygous (E-Tmod^-/-) mice to study E-Tmod expression patterns in the retina. The results showed that blue X-gal-positive cells were located in the dendrites of horizontal cells in both E-Tmod^+/lacZ and E-Tmod^-/- mice, especially in the HCs pedicle area. However, the results showed little staining being present in the lay of amacrine and ganglion cells with a salt pattern. Since their dendrites are oriented laterally in a plane and form most complicated synapses with multiple cone photoreceptors, horizontal cells are subjected to a greater stress and strain than vertically oriented neurons, such as ganglion cells. The specific E-Tmod expression suggests its role in protecting horizontal cells from mechanical damages in Glaucoma. In addition, X-gal staining result showed that photoreceptors layers did not be detected in the homozygous mice (E-Tmod^-/-), which suggests that E-Tmod not only protects HCs from mechanical damage, but also maintain the survival of photoreceptors.