Lens parameters and myopic shift in nuclear cataract after vitrectomy

Area of Science:

• Ophthalmology
• Optical Physics

Background:

• Nuclear cataract development post-pars plana vitrectomy (PPV) can induce refractive changes.
• Lenticular myopia is a significant cause of these refractive shifts, linked to alterations in lens parameters.

Purpose of the Study:

• To investigate the relationship between specific lens parameters and spherical equivalent refraction.
• To understand the development of nuclear cataract following PPV.

Main Methods:

• Prospective cohort study involving patients undergoing unilateral PPV.
• Pre- and post-operative measurements included subjective refraction, ocular biometry, and swept-source anterior segment optical coherence tomography (SS-ASOCT).
• Lens power, refractive index, and nuclear density were calculated and quantified using established formulas and SS-ASOCT imaging.

Main Results:

• A significant myopic refractive shift (-2.81 ± 2.36D) was observed in operated eyes.
• Increased lens power, refractive index, and thickness correlated with the myopic shift.
• Lens power was the primary driver of the myopic shift (R-squared: 0.80), while refractive index changes determined lens power alterations (R-squared: 0.98).
• Lens nuclear density showed a positive correlation with both refractive index and lens power.

Conclusions:

• Changes in the lens refractive index are the primary cause of lenticular myopia post-PPV.
• Lens nuclear density serves as a viable in vivo measure for assessing changes in lens refractive index and power.