Morphological changes of human crystalline lens in myopia

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optometry

Background:

• Myopia (nearsightedness) is a prevalent refractive error with complex etiologies.
• Understanding ocular biometric changes, particularly in the crystalline lens, is crucial for myopia research.
• Previous studies have explored various ocular parameters, but detailed 3-D analysis of the crystalline lens in myopia is ongoing.

Purpose of the Study:

• To comprehensively assess ocular biometric parameters, focusing on the crystalline lens, in myopic and emmetropic individuals.
• To investigate the relationship between refractive error, axial length, and specific crystalline lens characteristics.
• To elucidate the role of the crystalline lens in counteracting axial elongation associated with myopia.

Main Methods:

• Utilized 3-D optical coherence tomography (OCT) to evaluate ocular structures.
• Measured anterior chamber depth, corneal curvature, and multiple crystalline lens parameters (thickness, diameter, volume, power, etc.).
• Analyzed biometric data as a function of refractive error and axial length, controlling for age.

Main Results:

• Identified significant changes in the crystalline lens with myopia, including thinning and equatorial/capsular stretching, while lens volume remained constant.
• Observed a reduction in crystalline lens power correlating with axial elongation in myopic eyes.
• Found that corneal power was unaffected by the degree of myopia or axial length.

Conclusions:

• The crystalline lens undergoes adaptive changes in myopia, contributing to refractive error compensation.
• Lens thinning and stretching appear to be key mechanisms in myopia development.
• Axial elongation in myopia is partially offset by a reduction in crystalline lens power, with the cornea playing a neutral role.