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Postnatal regression of the tunica vasculosa lentis
1Department of Pediatrics and Child Health, Johannesburg Hospital, South Africa.
Insights
Premature delivery does not accelerate the regression of the tunica vasculosa lentis (TVL). The rate of TVL disappearance is similar to in utero development, regardless of postnatal age, aiding gestational age assessment.
Area of Science:
- Neonatal Ophthalmology
- Perinatal Medicine
- Developmental Biology
Background:
- The tunica vasculosa lentis (TVL) is a fetal vascular system that normally regresses after birth.
- Previous research correlated TVL appearance at birth with gestational age in premature infants (27-34 weeks).
- The rate of TVL regression in premature infants postnatally has not been extensively studied.
Purpose of the Study:
- To investigate the effect of postnatal age on TVL regression rate in premature infants.
- To compare the postnatal TVL regression rate with the in utero rate.
- To determine if premature delivery impacts TVL regression timing.
Main Methods:
- Fifty-eight premature infants were enrolled.
- Gestational age was assessed using the Ballard method.
- Lens examinations via direct ophthalmoscopy were conducted within 36 hours of birth and weekly thereafter.
- TVL regression was graded using Hittner's system (Grade IV to I).
- Data were analyzed and compared based on postconceptional age.
Main Results:
- No significant differences in TVL disappearance rate were observed between infants at equivalent postconceptional ages, irrespective of postnatal age.
- Premature delivery was not associated with accelerated regression of the TVL.
- The rate of TVL regression closely mirrored in utero developmental patterns.
Conclusions:
- Postnatal age does not significantly alter the rate of tunica vasculosa lentis regression in premature infants.
- TVL regression follows a predictable pattern, similar to in utero development, even after premature birth.
- These findings support the use of TVL regression for estimating gestational age in preterm infants, particularly when other methods are unreliable or unavailable.
Abstract:
Previous studies have shown a good correlation between appearance of the tunica vasculosa lentis (TVL) at birth and gestational age in 27-34 week premature infants. We studied the effect of postnatal age on the rate of regression of the TVL in premature infants to assess whether this occurred at a similar rate to that in utero. Fifty-eight premature infants were enrolled into the study. Gestational age was assessed using the method described by Ballard. Lens examination was by direct ophthalmoscopy within 36 hours of birth and then on a weekly basis. Regression of the TVL was graded according to the system described by Hittner; grade IV being the most immature (vascularity covering virtually the entire anterior surface of the lens) to grade I (vascular regression to a point at which only occasional vessels are visualized). Results were analyzed and compared according to postconceptional age. No significant differences were found in the rate of disappearance of the TVL when infants were studied at equivalent postconceptional ages irrespective of postnatal age. Thus, premature delivery was not associated with accelerated regression of the TVL. These findings may be useful in assessing gestational age of a preterm infant who has not had an assessment of gestational age within the first days after birth or who is transferred to a high-care centre beyond the stage when other gestational aging systems are considered reliable.