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Convergence and Accommodation Development Is Preprogrammed in Premature Infants
Anna M Horwood1, Sonia S Toor2, Patricia M Riddell2
1Infant Vision Laboratory School of Psychology & Clinical Language Sciences, University of Reading, Reading, United Kingdom 2Orthoptic Department, Royal Berkshire Hospital, Reading, United Kingdom.
Insights
Visual development in preterm infants appears preprogrammed, not experience-driven. Few differences in vergence and accommodation were found when matched by corrected age, suggesting maturation is innate.
Area of Science:
- Ophthalmology
- Developmental Neuroscience
- Pediatric Vision
Background:
- Visual development in infants is crucial for long-term ocular health.
- Preterm infants may experience altered visual input compared to full-term infants.
- Understanding the drivers of vergence and accommodation development is key to identifying potential deficits.
Purpose of the Study:
- To investigate whether vergence and accommodation development in preterm infants is preprogrammed or experience-driven.
- To compare visual development trajectories between preterm and full-term infants.
Main Methods:
- Thirty-two preterm and 45 full-term infants were studied for 6 months postnatally.
- Simultaneous accommodation and convergence were measured using an infrared photorefractor.
- Responses were analyzed by corrected (gestational) and chronological (postnatal) age.
Main Results:
- When matched by corrected age, preterm and full-term infants showed minimal differences in vergence and accommodation.
- Compared by chronological age, preterm infants exhibited more variable responses, including reduced vergence and accommodation gains.
- Preterm infants showed reduced vergence response at 0.33m and increased accommodation at 2m compared to full-term infants.
Conclusions:
- Vergence and accommodation maturation in preterm infants appears preprogrammed, independent of visual experience.
- The findings suggest that visual maturation is largely innate.
- Prolonged immature visual responses in preterm infants may increase the risk of oculomotor deficits like strabismus.
Purpose:
This study investigated whether vergence and accommodation development in preterm infants is preprogrammed or is driven by experience.
Methods:
Thirty-two healthy infants, born at mean 34 weeks gestation (range, 31.2-36 weeks), were compared with 45 healthy full-term infants (mean 40.0 weeks) over a 6-month period, starting at 4 to 6 weeks postnatally. Simultaneous accommodation and convergence to a detailed target were measured using a Plusoptix PowerRefII infrared photorefractor as a target moved between 0.33 and 2 m. Stimulus/response gains and responses at 0.33 and 2 m were compared by both corrected (gestational) age and chronological (postnatal) age.
Results:
When compared by their corrected age, preterm and full-term infants showed few significant differences in vergence and accommodation responses after 6 to 7 weeks of age. However, when compared by chronological age, preterm infants' responses were more variable, with significantly reduced vergence gains, reduced vergence response at 0.33 m, reduced accommodation gain, and increased accommodation at 2 m compared to full-term infants between 8 and 13 weeks after birth.
Conclusions:
When matched by corrected age, vergence and accommodation in preterm infants show few differences from full-term infants' responses. Maturation appears preprogrammed and is not advanced by visual experience. Longer periods of immature visual responses might leave preterm infants more at risk of development of oculomotor deficits such as strabismus.
