Choroidal changes in lens-induced myopia in guinea pigs

Area of Science:

• Ophthalmology
• Myopia Research
• Choroidal Physiology

Background:

• Lens-induced myopia (LIM) is a significant research area in understanding refractive error development.
• The choroid, a vascular layer of the eye, is increasingly recognized for its role in myopia.
• Investigating choroidal changes in myopia can reveal potential therapeutic targets.

Purpose of the Study:

• To investigate the role of the choroid in the development of lens-induced myopia (LIM) in a guinea pig model.
• To assess changes in choroidal thickness, vascularity, and nitric oxide synthase (NOS) expression during myopia progression.

Main Methods:

• Guinea pigs were induced with lens-induced myopia (LIM) or served as normal controls (NC).
• Refraction and axial length were measured using streak retinoscopy and A-scan ultrasonography.
• Choroidal thickness (ChT), choriocapillaris vessel density (VDCC), and choroidal layer vessel density (VDCL) were assessed via Spectral-domain Optical Coherence Tomography Angiography (SD-OCT).
• Choroidal expression of NOS enzymes (eNOS, nNOS) was analyzed at mRNA and protein levels.

Main Results:

• LIM group showed significant increases in refraction and axial length compared to NC group at 2 and 4 weeks.
• Choroidal thickness (ChT) and choriocapillaris vessel density (VDCC) were significantly decreased in the LIM group.
• Choroidal layer vessel density (VDCL) also showed a decreasing trend in the LIM group.
• Increased mRNA and protein expression of NOS enzymes (eNOS, nNOS) was observed in the choroid of the LIM group.
• Choroidal thickness was positively correlated with VDCC and VDCL, while NOS expression was negatively correlated with these parameters.

Conclusions:

• Myopia development is associated with reduced choroidal thickness and vascular density.
• Increased nitric oxide synthase (NOS) expression in the choroid correlates with myopia progression.
• Nitric oxide (NO) likely plays a crucial role in regulating choroidal function during myopia development.