Abstract
Purpose: :
Congenital high myopia is an early onset enlargement of the eye globes that carries a high risk for retinal detachment. Where the genetic basis of congenital high myopia has been established, mutations in genes encoding extracellular matrix proteins of the vitreous body (VB) and the inner limiting membrane (ILM) have frequently been implicated. The present study introduces the chick embryo as a model system to study the role of ILM and VB in regulating eye size.
Methods: :
The ILM and VB were disrupted by injecting collagenase into eyes of E5 chick embryos. The digestion of VB and ILM proteins was monitored by western blotting and immunocytochemistry. Eye size was assessed up to 9 days after the enzyme injections.
Results: :
Intraocular injection of collagenase led to the disruption of the ILM and the VB by digesting their collagen constituents. Once disrupted, the ILM and the collagen II fibrillar network did not regenerate despite continued synthesis of all VB and ILM proteins. ILM and VB disruption resulted in eye enlargement of 50% within 4 days. The increase in eye size was greatly reduced by reconstituting the ILM.
Conclusions: :
The present data show that the ILM and the VB play a major role in the early regulation of eye size. We speculate that the integrity of the vitreo–retinal border is important in preventing congenital high myopia.
Keywords: myopia • extracellular matrix • vitreous