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Choyce lens warp testing: effect of temperature and pressure changes
Journal - American Intra-Ocular Implant Society
|July 1, 1978
Summary
Choyce-style intraocular lenses (IOLs) exhibit varying thermal responses. While Perspex lenses resist deformation better, no significant deformation occurs under simulated physiological conditions, highlighting the need for careful handling and inspection of all IOLs.
Area of Science:
- Ophthalmology
- Materials Science
- Biomedical Engineering
Background:
- Intraocular lenses (IOLs) are critical for vision restoration after cataract surgery.
- Thermoplastic materials used in IOLs can be susceptible to thermal deformation, impacting optical performance.
- Different manufacturing processes and material compositions may influence IOL thermal stability.
Purpose of the Study:
- To compare the thermal response of Choyce-style IOLs made from different polymethyl methacrylate (PMMA) materials.
- To evaluate IOL deformation under simulated physiological temperatures and pressures.
- To assess the implications of thermal variability for IOL handling, packaging, and clinical acceptance.
Main Methods:
- Comparative analysis of Choyce-style IOLs fabricated from ICI Perspex CQ and Rohm & Haas injection molded PMMA.
- Exposure of IOLs to simulated physiological temperatures and pressures to assess deformation.
- Visual inspection and tactile testing (foot depression) for flatness and rocking/lift.
Main Results:
- ICI Perspex CQ lenses demonstrated greater resistance to high-temperature deformation compared to Rohm & Haas PMMA lenses.
- No significant lens deformation was observed for either lens type under simulated physiological conditions.
- Variability in thermal response was noted between individual lenses and even between different parts of the same lens.
Conclusions:
- While differences in thermal resistance exist between PMMA types, simulated physiological conditions did not induce significant deformation.
- Improved packaging and meticulous pre-implantation inspection are essential due to the general susceptibility of thermoplastics to heat during transportation.
- Intraocular lens variability necessitates careful quality control and cautions against unsubstantiated claims, emphasizing the importance of flatness testing.