Eye growth and myopia development: Unifying theory and Matlab model. (1st March 2016)

• Record Type: Journal Article
• Authors: Hung, George K.; Mahadas, Kausalendra; Mohammad, Faisal
• Is Part Of: Computers in biology and medicine. Volume 70(2016)
• Page Start: 106
• Page End: 118
• Publication Date: 2016-03-01
• Subjects: AR accommodative response -- AS/R accommodative stimulus/response function -- Akt/GSK3 Ak mouse with developed thymona/Glycogen Synthase Kinase 3, (also called Protein Kinase B) -- DAT dopamine active transporter -- DOF depth of focus -- EGR-1 Early Growth Response Protein 1 -- GUI graphical user interface -- IGF-1 Insulin-Like Growth Factor 1 -- IGFBP Insulin-Like Growth Factor Binding Protein -- IRDT Incremental Retinal-Defocus Theory -- LASIK Laser-Assisted in Situ Keratomileusis -- NITM nearwork-induced transient myopia -- RPE retinal pigment epithelium; Myopia -- Blur -- Dopamine -- Emmetropization -- Nearwork-induced transient myopia -- Refractive error -- Model simulation -- Incremental Retinal-Defocus Theory (IRDT); Medicine -- Data processing -- Periodicals; Biology -- Data processing -- Periodicals; 610.285
• DOI: 10.1016/j.compbiomed.2016.01.003
• Languages: English
• ISSNs: 0010-4825

Abstract

Abstract: The aim of this article is to present an updated unifying theory of the mechanisms underlying eye growth and myopia development. A series of model simulation programs were developed to illustrate the mechanism of eye growth regulation and myopia development. Two fundamental processes are presumed to govern the relationship between physiological optics and eye growth: genetically pre-programmed signaling and blur feedback. Cornea/lens is considered to have only a genetically pre-programmed component, whereas eye growth is considered to have both a genetically pre-programmed and a blur feedback component. Moreover, based on the Incremental Retinal-Defocus Theory (IRDT), the rate of change of blur size provides the direction for blur-driven regulation. The various factors affecting eye growth are shown in 5 simulations: (1 – unregulated eye growth): blur feedback is rendered ineffective, as in the case of form deprivation, so there is only genetically pre-programmed eye growth, generally resulting in myopia; (2 – regulated eye growth): blur feedback regulation demonstrates the emmetropization process, with abnormally excessive or reduced eye growth leading to myopia and hyperopia, respectively; (3 – repeated near–far viewing): simulation of large-to-small change in blur size as seen in the accommodative stimulus/response function, and via IRDT as well as nearwork-induced transient myopia (NITM), leading to the development of myopia; (4 – neurochemical bulk flow and diffusion): release of dopamine from the inner plexiform layer of the retina, and the subsequent diffusion and relay of neurochemical cascade show that a decrease in dopamine results in a reduction of proteoglycan synthesis rate, which leads to myopia; (5 – Simulink model): model of genetically pre-programmed signaling and blur feedback components that allows for different input functions to simulate experimental manipulations that result in hyperopia, emmetropia, and myopia. These model simulation programs (available upon request) can provide a useful tutorial for the general scientist and serve as a quantitative tool for researchers in eye growth and myopia.