Critical Periods and Amblyopia

Abstract

uring the past 20 years, basic science has shown that there are different critical periods for different visual functions during the development of the visual system. Visual functions processed at higher anatomical levels within the system have a later critical period than functions processed at lower levels. This general principle suggests that treatments for amblyopia should be followed in a logical sequence, with treatment for each visual function to be started before its critical period is over. However, critical periods for some visual functions, such as stereopsis, are not yet fully determined, and the optimal treatment is, therefore, unknown. This article summarizes the current extent of our knowledge and points to the gaps that need to be filled.

Is it impossible to acquire absolute pitch in adulthood?

“…Our finding also challenges the theoretical proposal that the critical period constrains the development of high-level cognitive abilities. This converges with findings that high-level visual and musical abilities continue to develop in adulthood (Daw, 1998;Trainor, 2005). This is also consistent with findings in language development (Flege et al, 1995;Singleton, 2001) and synesthesia (Bor et al, 2015) that acquisition of these abilities beyond the critical period is possible.…”

Is it impossible to acquire absolute pitch in adulthood?

“…Our finding also challenges the theoretical proposal that the critical period constrains the development of high-level cognitive abilities. This converges with findings that high-level visual and musical abilities continue to develop in adulthood (Daw, 1998;Trainor, 2005). This is also consistent with findings in language development (Flege et al, 1995;Singleton, 2001) and synesthesia (Bor et al, 2015) that acquisition of these abilities beyond the critical period is possible.…”

Is it impossible to acquire absolute pitch in adulthood?

“…Our finding also challenges the theoretical proposal that a critical period constrains the development of high-level cognitive abilities. This converges with findings in high-level vision (Daw, 1998) and musical development (Trainor, 2005) that high-level visual and musical abilities can continue to develop in adulthood. This is also consistent with the studies in language development (Flege et al, 1995;Singleton, 2001) and synesthesia (Bor et al, 2015), which show that acquisition of abilities comparable with native speakers and natural synesthetes beyond the critical period is possible.…”

Amblyopia and amblyopia treatment study

“…Thus, one can talk about 3 periods for acuity: the period of development of visual acuity (birth to 3-5 years of age), the period during which deprivation is effective in causing amblyopia (a few months to 7 or 8 years of age), and the period during which recovery from amblyopia can be obtained (time of deprivation to the teenaged years or even into the adult years). 12 A similar distinction of periods is found in the study of ocular dominance in animals. The nerve fibers from the lateral geniculate that terminate in layer IV of the visual cortex segregates into left and right eye stripes between birth and 6 weeks of age in the macaque monkey, but this pattern of stripes can be altered by monocular deprivation until 10 weeks of age.…”

Is it impossible to acquire absolute pitch in adulthood?

“…Our finding also challenges the theoretical proposal that the critical period constrains the development of high-level cognitive abilities. This converges with findings that high-level visual and musical abilities continue to develop in adulthood (Daw, 1998;Trainor, 2005). This is also consistent with findings in language development (Flege et al, 1995;Singleton, 2001) and synesthesia (Bor et al, 2015) that acquisition of these abilities beyond the critical period is possible.…”

Is it impossible to acquire absolute pitch in adulthood?

“…Our finding also challenges the theoretical proposal that a critical period constrains the development of high-level cognitive abilities. This converges with findings in high-level vision (Daw, 1998) and musical development (Trainor, 2005) that high-level visual and musical abilities can continue to develop in adulthood. This is also consistent with the studies in language development (Flege et al, 1995;Singleton, 2001) and synesthesia (Bor et al, 2015), which show that acquisition of abilities comparable with native speakers and natural synesthetes beyond the critical period is possible.…”

Amblyopia and amblyopia treatment study

“…Thus, one can talk about 3 periods for acuity: the period of development of visual acuity (birth to 3-5 years of age), the period during which deprivation is effective in causing amblyopia (a few months to 7 or 8 years of age), and the period during which recovery from amblyopia can be obtained (time of deprivation to the teenaged years or even into the adult years). 12 A similar distinction of periods is found in the study of ocular dominance in animals. The nerve fibers from the lateral geniculate that terminate in layer IV of the visual cortex segregates into left and right eye stripes between birth and 6 weeks of age in the macaque monkey, but this pattern of stripes can be altered by monocular deprivation until 10 weeks of age.…”

Is it impossible to acquire absolute pitch in adulthood?

“…Our finding also challenges the theoretical proposal that the critical period constrains the development of high-level cognitive abilities. This converges with findings that high-level visual and musical abilities continue to develop in adulthood (Daw, 1998;Trainor, 2005). This is also consistent with findings in language development (Flege et al, 1995;Singleton, 2001) and synesthesia (Bor et al, 2015) that acquisition of these abilities beyond the critical period is possible.…”

Is it impossible to acquire absolute pitch in adulthood?

“…Our finding also challenges the theoretical proposal that a critical period constrains the development of high-level cognitive abilities. This converges with findings in high-level vision (Daw, 1998) and musical development (Trainor, 2005) that high-level visual and musical abilities can continue to develop in adulthood. This is also consistent with the studies in language development (Flege et al, 1995;Singleton, 2001) and synesthesia (Bor et al, 2015), which show that acquisition of abilities comparable with native speakers and natural synesthetes beyond the critical period is possible.…”

Amblyopia and amblyopia treatment study

“…Thus, one can talk about 3 periods for acuity: the period of development of visual acuity (birth to 3-5 years of age), the period during which deprivation is effective in causing amblyopia (a few months to 7 or 8 years of age), and the period during which recovery from amblyopia can be obtained (time of deprivation to the teenaged years or even into the adult years). 12 A similar distinction of periods is found in the study of ocular dominance in animals. The nerve fibers from the lateral geniculate that terminate in layer IV of the visual cortex segregates into left and right eye stripes between birth and 6 weeks of age in the macaque monkey, but this pattern of stripes can be altered by monocular deprivation until 10 weeks of age.…”