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The quantity of rhodopsin in young human eyes
A B Fulton1, J Dodge, R M Hansen
1Department of Ophthalmology, Children's Hospital, Boston, MA.
Insights
Infants have significantly lower rhodopsin content than adults, about one-third. This difference in rhodopsin, a key visual pigment, likely limits dark-adapted vision sensitivity in young children.
Area of Science:
- Ophthalmology
- Developmental Biology
- Visual Neuroscience
Background:
- Rhodopsin is the primary photopigment responsible for dim-light vision.
- Previous studies suggested differences in visual sensitivity between infants and adults.
Purpose of the Study:
- To quantify and compare rhodopsin content in infant and adult human eyes.
- To investigate the relationship between rhodopsin levels and dark-adapted visual sensitivity in infants.
Main Methods:
- Assay of rhodopsin content from donor eyes across a range of ages (27 weeks gestation to 8 years, plus adults).
- Comparison of rhodopsin levels between infant and adult cohorts.
Main Results:
- Infants exhibit significantly lower rhodopsin content compared to adults.
- On average, young infants possess about one-third the rhodopsin content of adults.
- This reduction correlates with previously observed lower b-wave sensitivity in infants.
Conclusions:
- Photon capture by rhodopsin appears to be a limiting factor for dark-adapted visual sensitivity in young human infants.
- Findings in human infants align with similar observations in infant rats.
- Rhodopsin levels mature postnatally, impacting visual function development.
Abstract:
The rhodopsin content of 20 eyes of infants and children ages 27 weeks gestation to 8 years (11 donors) was assayed and compared to the rhodopsin content of adults (36 eyes; 19 donors). Infants have significantly lower rhodopsin contents than adults. On average the rhodopsin content of young infants is about a third of adults. Previously reported full-field b-wave sensitivity of young infants is about 0.5 log units, that is about a third, less than adults. Thus, as previously found in infant rats, photon capture by rhodopsin appears to limit the dark adapted sensitivity of young human infants.