Variations in manufacturing quality of diffractive multifocal lenses

Area of Science:

• Ophthalmology
• Materials Science
• Optical Engineering

Background:

• Advanced multifocal intraocular lenses (IOLs) utilize diffractive optics for vision correction.
• These lenses feature precise stepped discontinuities on their posterior surface, with step heights under 2 microns.
• Manufacturing requires high precision, around 0.02 mm, due to approximately 30 zones on a 6 mm lens.

Observation:

• Examination of implanted diffractive multifocal IOLs revealed unexpected features.
• Beyond the designed step boundaries, numerous small circular rims were identified.
• These rims are consistent with manufacturing artifacts rather than intended optical features.

Findings:

• The diffractive multifocal IOLs possess unintended circular rims, indicative of manufacturing flaws.
• These artifacts are distinct from the designed 2-micron step boundaries.
• The presence and nature of these artifacts suggest a potential source of variability in lens performance.

Implications:

• Manufacturing artifacts in diffractive multifocal IOLs may compromise visual quality.
• These imperfections could be responsible for the variable clinical acceptance and patient satisfaction observed.
• Further quality control in IOL manufacturing is crucial to ensure consistent visual outcomes.