Some aspects of cataract morphology: a SEM-study

Area of Science:

• Ophthalmology
• Biomaterials Science
• Cell Biology

Background:

• Senile cataracts are a leading cause of vision loss in the elderly.
• The precise ultrastructural changes in lens fibers contributing to cataract formation are not fully understood.
• Understanding these changes is crucial for developing targeted treatments.

Purpose of the Study:

• To investigate the ultrastructural morphology of lens fibers in senile cataracts using scanning electron microscopy (SEM).
• To identify specific changes in lens fiber proteins and their organization.
• To correlate observed structural alterations with changes in light dispersion.

Main Methods:

• Human lenses from elderly patients with senile cataracts were obtained.
• Lenses were processed for SEM, including equatorial fracture and gold sputtering.
• Cross-fractured surfaces were examined at high magnifications.

Main Results:

• While overall lens fiber structure appeared intact, higher magnifications revealed significant changes.
• Lens fiber material exhibited a brittle, granular, or fibrillar character.
• Recrystallization of lens fiber proteins formed finger-like, plate-like, or undulating substructures.
• Canal-like 'waterclefts' (Wasserspalten) were observed between altered protein regions.
• These structural changes, along with protein alterations, explain altered light dispersion.

Conclusions:

• Senile cataract formation involves significant ultrastructural changes in lens fiber proteins, including recrystallization and fragmentation.
• The presence of waterclefts and altered protein structures directly impacts light scattering within the lens.
• SEM provides valuable insights into the morphological basis of visual impairment in senile cataracts.