Adults Born Small for Gestational Age at Term Have Thinner Peripapillary Retinal Nerve Fiber Layers Than Controls

Tracing the influence of prenatal risk factors on the offspring retina: Focus on development and putative long-term consequences

BACKGROUND

Pregnancy represents a window of vulnerability to fetal development. Disruptions in the prenatal environment during this crucial period can increase the risk of the offspring developing diseases over the course of their lifetime. The central nervous system (CNS) has been shown to be particularly susceptible to changes during crucial developmental windows. To date, research focused on disruptions in the development of the CNS has predominantly centred on the brain, revealing a correlation between exposure to prenatal risk factors and the onset of neuropsychiatric disorders. Nevertheless, some studies indicate that the retina, which is part of the CNS, is also vulnerable to in utero alterations during pregnancy. Such changes may affect neuronal, glial and vascular components of the retina, compromising retinal structure and function and possibly impairing visual function.

METHODS

A search in the PubMed database was performed, and any literature concerning prenatal risk factors (drugs, diabetes, unbalanced diet, infection, glucocorticoids) affecting the offspring retina were included.

RESULTS

This review collects evidence on the cellular, structural and functional changes occurring in the retina triggered by maternal risk factors during pregnancy. We highlight the adverse impact on retinal development and its long-lasting effects, providing a critical analysis of the current knowledge while underlining areas for future research.

CONCLUSIONS

Appropriate recognition of the prenatal risk factors that negatively impact the developing retina may provide critical clues for the design of preventive strategies and for early therapeutic intervention that could change retinal pathology in the progeny.

Sex-Specific Differences in the Relationship Between Prematurity and Ocular Geometry

Purpose

To explore differences in the relationship between gestational age (GA) and birth weight (BW) percentile and ocular geometry between males and females.

Methods

The Gutenberg Prematurity Eye Study involved a prospective ophthalmic examination of adults, aged 18 to 52 years, who were born preterm or at term, in Germany. The associations between GA and BW percentile on the main outcome measures were evaluated by uni- and multivariable linear regression analyses. The main outcome measures were central corneal thickness, corneal radius, anterior chamber depth, lens thickness, posterior segment length, and central foveal thickness. Potential sex-specific differences and an effect modification by sex were analyzed.

Results

This study involved 438 participants (245 females, 193 males) with an average age of 28.6 ± 8.7 years. In female participants, central foveal thickness was negatively associated with a higher GA (B = -2.99; P < 0.001). Similarly, male participants also demonstrated a negative association between central foveal thickness and GA (B = -4.27; P < 0.001). The multivariable model with effect modification revealed that the central foveal thickness was thicker with lower GA. There was an association between the effect modification of GA with sex and central foveal thickness, demonstrating a more pronounced effect of GA on central foveal thickness in male participants (B = 1.29; P = 0.04).

Conclusions

This study identified a sex-specific correlation between lower GA and thicker central foveal thickness, suggesting differences in the developmental trajectory of this biometric parameter concerning GA. A thicker central foveal thickness might affect the visual acuity of individuals born preterm in adulthood, with a more pronounced impact in males and a potential predisposition to age-related diseases later in life. Sex did not influence the association of GA or BW percentile to other ocular geometric parameters.

Fetal Growth Restriction Leads to an Enlarged Cup-to-Disc Ratio in Adults Born at Full Term

PURPOSE

This study explores associations between fetal growth restriction or excessive fetal growth, along with perinatal factors on the optic nerve head morphology in adulthood.

DESIGN

Retrospective cohort study.

METHODS

This retrospective cohort study involved a prospective ophthalmological examination of individuals born at full term (with a gestational age of ≥37 weeks) from 1969 to 2002. Each participant underwent nonmydriatic fundus camera photography to capture images of the optic discs, followed by manual measurements. The vertical cup-to-disc ratio (VCDR) and optic disc area were examined and analyzed in relation to the baby's birth weight relative to the gestational age. These categories included those with former moderate (birth weight percentile between the 3rd and <10th), severe SGA (below the third percentile), normal (AGA, 10th-90th percentile), and moderately (birth weight >90th-97th percentile) and severely (birth weight >97th percentile) large for gestational age (LGA) adults within the age range of 18 to 52 years.

RESULTS

Overall, 535 eyes of 280 individuals (age 29.7 ± 9.2 years, 144 females) born at full term were included. Multivariable analysis showed a significant association between a larger VCDR and the severe SGA group (B = 0.05, 95% CI 0.01-0.10; P = .02). In the univariable model, placental insufficiency was associated with VCDR (B = 0.10, 95% CI 0.01-0.19; P = .03). Other perinatal factors did not demonstrate an association with VCDR. Furthermore, there was an indication of an association suggesting a smaller optic disc area in individuals born moderately SGA at full term (B = -0.17, 95% CI -0.33 to -0.001; P = .05).

CONCLUSIONS

This study provides evidence that individuals born at-term with severe SGA have an increased VCDR, suggesting that fetal growth restriction has a lasting impact on optic disc morphology independent of prematurity throughout adulthood.

Maternal diabetes affects rat offspring retinal structure and function: Sex-specific vulnerabilities at infancy

AIMS

Maternal diabetes negatively impacts the offspring's brain, but little is known about its effects on the retina, which is also part of the central nervous system. We hypothesized that maternal diabetes adversely influences offspring retina development leading to structural and functional deficits.

MAIN METHODS

Retinal structure and function were evaluated at infancy, by optical coherence tomography and electroretinography, in male and female offspring of control, diabetic and diabetic-treated with insulin Wistar rats.

KEY FINDINGS

Maternal diabetes induced a delay in male and female offspring eye-opening, while insulin treatment expedited it. Structural analysis showed that maternal diabetes decreased the thickness of the inner and outer segment layer of photoreceptors in male offspring. Electroretinography also revealed that maternal diabetes decreased the amplitude of scotopic b-wave and flicker response in males, suggesting bipolar cells and cone photoreceptor dysfunction, an effect not observed in females. Conversely, maternal diabetes decreased cone arrestin protein levels in female retinas, while not affecting cone photoreceptor number. Dam insulin therapy was efficient in preventing the offspring photoreceptor changes.

SIGNIFICANCE

Our results suggest that photoreceptors are affected by maternal diabetes, which may account for visual impairments at infancy. Notably, both male and female offspring presented specific vulnerabilities to hyperglycemia in this sensitive period of development.

Normative data for macular and retinal nerve fibre layer thickness in healthy German children and adolescents using optical coherence tomography

PURPOSE

To establish normative data for macular thickness, macular volume and peripapillary retinal nerve fibre layer (RNFL) thickness using Spectralis® spectral-domain optical coherence tomography (SD-OCT) in healthy German children and adolescents and investigate influencing factors.

METHODS

The cross-sectional study included the right eye of 695 children with at least one complete retinal OCT scan. As part of the LIFE Child study, the children underwent an ophthalmological examination including axial length (AL), spherical equivalent (SE) and OCT measurements. Various questionnaires were answered by the children or their parents to identify media use or outdoor time. Multiple linear regression models were used to investigate the potential influencing factors.

RESULTS

A total of 342 boys and 353 girls with an average age (SD) of 12.91 (3.29) years participated. The mean AL (SD) was 23.20 (0.86) mm. The mean macular thickness (SD) was 320.53 (12.29) μm and the mean RNFL thickness (SD) was 102.88 (8.79) μm. Statistical analysis revealed a significant correlation between average macular thickness and age (p < 0.001, β = 0.77) as well as AL (p < 0.001, β = -4.06). In addition, boys had thicker maculae (p < 0.001, β = 5.36). The RNFL thickness showed no significant correlation with children's age (p > 0.05), but with AL (p = 0.002, β = -2.15), birth weight (p = 0.02, β = 0.003) and a gender-specific effect of the body mass index standard deviation score for male participants (p = 0.02, β = 1.93).

CONCLUSION

This study provides normative data and correlations between macular and RNFL thickness in healthy German children. Especially age, gender and AL must be taken into account when evaluating quantitative OCT measurements to classify them as normal.