Analysis of intraocular lens surface properties with atomic force microscopy

Area of Science:

• Ophthalmic biomaterials science
• Surface metrology
• Optical engineering

Background:

• Intraocular lenses (IOLs) are critical for vision restoration after cataract surgery.
• The surface properties of IOLs can influence biocompatibility and optical performance.
• Understanding IOL surface topography is essential for optimizing lens design and manufacturing.

Purpose of the Study:

• To quantitatively analyze the surface optics of four commercially available intraocular lenses (IOLs).
• To compare the surface roughness and topography of different IOL biomaterials using atomic force microscopy (AFM).

Main Methods:

• Surface topography and roughness of poly(methyl methacrylate) (PMMA), silicone, hydrophobic acrylic, and hydrophilic acrylic IOLs were assessed.
• Atomic force microscopy (AFM) in contact mode was employed in a liquid environment.
• Measurements were conducted on the posterior optic surface of IOLs across 10 µm² areas.

Main Results:

• AFM provided high-resolution imaging of IOL optic surfaces, revealing distinct topographical features based on biomaterial.
• Significant differences in root-mean-square (RMS) roughness were observed among the IOL materials (P < .001).
• Hydrophobic acrylic (3.8 nm ± 0.2) and silicone (4.0 nm ± 0.5) IOLs demonstrated the lowest mean surface roughness, whereas PMMA IOLs exhibited the highest (6.6 nm ± 0.3 and 7.0 nm ± 0.6).

Conclusions:

• Atomic force microscopy is a precise and effective tool for evaluating IOL surface optics.
• The manufacturing process significantly impacts the surface topography of intraocular lenses.
• Variations in IOL surface characteristics may have implications for clinical performance and biocompatibility.