Prevalence, concordance, and heritability of posterior vitreous detachment (PVD) in a twin population

Abstract

Purpose : The pathophysiology of PVD is not fully understood; twin studies can estimate the relative importance of genetic and environmental factors for common eye diseases and traits. Therefore, the aim of this study is to explore the prevalence, concordance and heritability of PVD in a twin population.

Methods : Macular optical coherence tomography (OCT) scans (Optovue iVue 100, Optovue, Freemont, CA) taken between 2014-2022 from participants of the TwinsUK cohort aged 40 years and older were graded for signs of total and partial PVD. Zygosity was ascertained using genetic data or the “peas in a pod” questionnaire. Casewise concordance was calculated for mono- (MZ) and dizygotic (DZ) twin pairs using 2C/(2C + D), where C=number of twin pairs concordant and D=number of twin pairs discordant for PVD. The covariance of PVD within MZ and DZ twin pairs was compared, and genetic modelling techniques were used to determine the relative contributions of genes and environment to the variation in PVD and adjusted for age using the OpenMx (http://openmx.psyc.virginia.edu/) package in R.

Results : OCT scans from 3406 twin participants (941 monozygotic [MZ] and 633 dizygotic [DZ] twin pairs) aged 40-89 (mean 62 SD 10.4, median 63 years) were analysed. The overall prevalence of any PVD in either eye was 21.3% (20.0-22.7). 68 MZ and 34 DZ twin pairs were concordant for PVD. 111 MZ and 116 DZ twin pairs were discordant for PVD. Concordance was 0.55 and 0.37 for MZ and DZ twins, respectively, suggesting a role for genes. A model combining additive genetic and unique environmental effects provided the best fit and resulted in a PVD heritability estimate of 0.53 (95% CI, 0.43–0.62).

Conclusions : To our knowledge this is the first classic twin study describing the concordance and heritability of PVD. Whilst OCT is not the gold standard for diagnosing PVD, the findings nevertheless suggest that PVD has significant underlying genetic influences. Further research to identify genes associated with PVD and therefore mechanisms involved in PVD is needed.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.