[Halos and multifocal intraocular lenses: origin and interpretation]
F Alba-Bueno1, F Vega1, M S Millán1
1Departamento de Óptica y Optometría, Universidad Politécnica de Cataluña, Terrassa, Barcelona, España.
Archivos De La Sociedad Espanola De Oftalmologia
|June 22, 2014
Summary
The addition power of multifocal intraocular lenses (MIOL) directly impacts halo size, with higher additions causing larger halos. Apodized MIOLs can reduce halo diameter in distance vision compared to non-apodized ones.
Area of Science:
- Ophthalmic Optics
- Optical Engineering
- Visual Science
Background:
- Halos are visual artifacts perceived by patients with multifocal intraocular lenses (MIOL).
- Understanding halo formation is crucial for optimizing MIOL design and patient visual quality.
Purpose of the Study:
- To theoretically and experimentally characterize the halos produced by multifocal intraocular lenses (MIOL).
- To compare halo characteristics across different MIOL designs and optical parameters.
Main Methods:
- Utilized geometrical optics to derive formulas for halo diameter based on lens addition power, base power, and IOL diameter.
- Performed in vitro analysis of the intensity profile of a pinhole image focused by each MIOL focal point.
- Compared halos from various MIOLs with different designs (apodized vs. non-apodized, spherical vs. aspheric) and addition powers on an optical bench.
Main Results:
- Halo diameter increases proportionally with the MIOL's addition power.
- Apodized MIOLs exhibited smaller distance halos than non-apodized MIOLs, with similar near vision halo sizes but higher intensity.
- Spherical MIOLs showed larger distance halos and smaller, higher-intensity near halos compared to aspheric counterparts due to spherical aberration.
Conclusions:
- The addition power is a primary determinant of halo size in MIOLs.
- MIOL design features, including apodization and base spherical/aspheric design, significantly influence halo characteristics.
- Trifocal-diffractive IOLs can produce noticeable double-halo effects.
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