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Key Event Title
Decreased, Eye size
|Level of Biological Organization|
Key Event Components
Key Event Overview
AOPs Including This Key Event
|AOP Name||Role of event in AOP||Point of Contact||Author Status||OECD Status|
|TPOi eye size||KeyEvent||Lucia Vergauwen (send email)||Under development: Not open for comment. Do not cite||Under Development|
|Inhibition of Fyna leading to increased mortality||KeyEvent||Vid Modic (send email)||Open for citation & comment|
Key Event Description
Animals show a wide variation in relative eye size (compared to body size) both within and between species. Eye size is directly related to visual ability. Eye size, and in particular the eye to body ratio, gives a lot of information about the quality of vision of the individual but also about its lifestyle. For example, eye size provides information on nocturnal and diurnal lifestyles in mammals (Kirk, 2006). Previous studies of eye design suggest a common organizing principle about how the activity pattern is reflected in the size and shape of the eyes (Hall, 2008).
Large eyes generally have greater visual sensitivity as they have relatively large corneas and lenses, e.g. in primates (e.g (Kirk, 2006; Ross and Kirk, 2007), birds (e.g (Brooke et al., 1999; Hall, 2008), lizards (Hall, 2008), fish (e.g. (Bejarano-Escobar et al., 2010; Karvonen and Seppälä, 2008) and other species. Increasing the size of the whole eye can increase resolution or sensitivity without having to decrease the other. For example, a larger eye with a longer focal length may be more sensitive without loss of acuity, or it may be more acute without loss of sensitivity. However, a constraint for large eyes is that they must always fit inside an animal's head and are associated with increased development and maintenance costs (Caves et al., 2017).
Microphthalmia is a congenital ocular deformation characterized by abnormally small eyes, with or without structural abnormalities (Le et al., 2012). Microphthalmia can occur as a consequence of a number of potential mechanisms, including but not limited to general developmental delay, increased cell death, reduced cell proliferation, and reduced cell differentiation within the developing eye (Stenkamp et al., 2002).
How It Is Measured or Detected
- Use of plasticine spherical ball (Brooke et al., 1999)
- Ocular biometry (Kang and Wildsoet, 2016)
- Relative eye size: larger corneal diameters relative to the axial length or larger eye diameter relative to body length (Baumann et al., 2016; Hall, 2008) determined by morphological analysis with electromicroscopy or analysis of digital images
- Morphological live imaging + Aqueous outflow tract visualization (Chawla et al., 2018)
Domain of Applicability
Taxonomic applicability: Applicable to a large range of species. For instance, eye length is positively correlated with visual acuity across mammals (Heesy and Hall 2010; Veilleux and Kirk 2014), birds (Hall and Heesy 2011), and fishes (Baumann et al., 2016; Caves et al., 2017; Corral-López et al., 2017).
Sex applicability: Difference in male/female probably due to general differences in body size, highlighted by some studies (Corral-López et al., 2017; Svanbäck and Johansson, 2019).
Baumann, L., Ros, A., Rehberger, K., Neuhauss, S.C.F., Segner, H., 2016. Thyroid disruption in zebrafish (Danio rerio) larvae: Different molecular response patterns lead to impaired eye development and visual functions. Aquat. Toxicol. 172, 44–55. https://doi.org/10.1016/j.aquatox.2015.12.015
Bejarano-Escobar, R., Blasco, M., DeGrip, W.J., Oyola-Velasco, J.A., Martín-Partido, G., Francisco-Morcillo, J., 2010. Eye development and retinal differentiation in an altricial fish species, the senegalese sole (Solea senegalensis, Kaup 1858). J. Exp. Zool. Part B Mol. Dev. Evol. 314 B, 580–605. https://doi.org/10.1002/jez.b.21363
Brooke, M.D.L., Hanley, S., Laughlin, S.B., 1999. The scaling of eye size with body mass in birds. Proc. R. Soc. B Biol. Sci. 266, 405–412. https://doi.org/10.1098/rspb.1999.0652
Caves, E.M., Sutton, T.T., Johnsen, S., 2017. Visual acuity in ray-finned fishes correlates with eye size and habitat. J. Exp. Biol. 220, 1586–1596. https://doi.org/10.1242/jeb.151183
Chawla, B., Swain, W., Williams, A.L., Bohnsack, B.L., 2018. Retinoic acid maintains function of neural crest–derived ocular and craniofacial structures in adult zebrafish. Investig. Ophthalmol. Vis. Sci. 59, 1924–1935. https://doi.org/10.1167/iovs.17-22845
Corral-López, A., Garate-Olaizola, M., Buechel, S.D., Kolm, N., Kotrschal, A., 2017. On the role of body size, brain size, and eye size in visual acuity. Behav. Ecol. Sociobiol. 71. https://doi.org/10.1007/s00265-017-2408-z
Hall, M.I., 2008. Comparative analysis of the size and shape of the lizard eye. Zoology 111, 62–75. https://doi.org/10.1016/j.zool.2007.04.003
Kang, P., Wildsoet, C.F., 2016. Acute and short-term changes in visual function with multifocal soft contact lens wear in young adults. Contact Lens Anterior Eye 39, 133–140. https://doi.org/10.1016/j.clae.2015.09.004
Karvonen, A., Seppälä, O., 2008. Eye fluke infection and lens size reduction in fish: A quantitative analysis. Dis. Aquat. Organ. 80, 21–26. https://doi.org/10.3354/dao01918
Kashyap, B., Frederickson, L.C., & Stenkamp, D.L., 2008. Mechanisms for persistent microphthalmia following ethanol exposure during retinal neurogenesis in zebrafish embryos. Vis. Neurosci. 24(3), 409–421. https://doi.org/10.1017/S0952523807070423
Kirk, E.C., 2006. Effects of activity pattern on eye size and orbital aperture size in primates. J. Hum. Evol. 51, 159–170. https://doi.org/10.1016/j.jhevol.2006.02.004
Le, H.G., Dowling, J.E., & Cameron, D.J., 2012. Early retinoic acid deprivation in developing zebrafish results in microphthalmia. Vis. Neurosci. 29(4–5), 219–228. https://doi.org/10.1017/S0952523812000296
Marsh-Armstrong, N., Mccaffery, P., Gilbert, W., Dowling, J.E., & Dräger, U.C., 1994. Retinoic acid is necessary for development of the ventral retina in zebrafish. Proc. Natl. Acad. Sci. U S A. 91(15), 7286–7290. https://doi.org/10.1073/pnas.91.15.7286
Ross, C.F., Kirk, E.C., 2007. Evolution of eye size and shape in primates. J. Hum. Evol. 52, 294–313. https://doi.org/10.1016/j.jhevol.2006.09.006
Stenkamp, D.L., Frey, R.A., Mallory, D.E., & Shupe, E.E., 2002. Embryonic Retinal Gene Expression in Sonic-You Mutant Zebrafish. Dev. Dyn., 225, 344–350. https://doi.org/10.1002/dvdy.10165
Svanbäck, R., Johansson, F., 2019. Predation selects for smaller eye size in a vertebrate: Effects of environmental conditions and sex. Proc. R. Soc. B Biol. Sci. 286. https://doi.org/10.1098/rspb.2018.2625
Wold, M., Beckmann, M., Poitra, S., Espinoza, A., Longie, R., Mersereau, E., Darland, D.C., Darland, T., 2017. The longitudinal effects of early developmental cadmium exposure on conditioned place preference and cardiovascular physiology in zebrafish. Aquat. Toxicol. 191, 73–84. https://doi.org/10.1016/j.aquatox.2017.07.017