Eye lens types in comparison: monofocal, EDOF and multifocal

When it comes to choosing an intraocular lens (IOL) after cataract surgery or for refractive lens exchange surgery, a comprehensive understanding of the different lens types is crucial. Each lens type offers specific advantages and disadvantages for both near and distance vision and can cause different optical side effects. The three main types – monofocal, EDOF (Extended Depth of Focus) and multifocal lenses – are compared in detail below.

Comparison table: Monofocal, EDOF and multifocal lenses

Monofocal lenses

Advantages

• Excellent distance vision: Monofocal lenses offer excellent visual acuity for a specific distance, usually for the distance.
• High contrast sensitivity: They provide the most natural and high-contrast vision of all lens types.
• Less sensitivity to glare: patients experience less glare and light reflections compared to other lens types.
• Cost-effective: Generally the cheapest option of the three lens types.
• Proven technology: Many years of clinical experience and high reliability.

Disadvantages

• Limited focus range: Focusing only at one distance – either far, medium or close.
• Spectacle dependency: Spectacles are almost always required for at least one distance (usually near vision).
• Monovision adaptation: If a monovision strategy is chosen (one eye for distance, one for near), the adaptation may take longer and affect depth perception.

Optical side effects

• Minimal: Very low probability of halos or glare.
• Natural night vision: Best night vision of all lens types.
• Hardly any reduction in visual quality: even in difficult lighting conditions.

EDOF lenses (Extended Depth of Focus)

Advantages

• Extended focus range: Provide a smooth transition from long to medium range vision.
• Reduced spectacle dependency: Usually spectacle-free for long and medium distances.
• Good contrast sensitivity: Better than with multifocal lenses, although not as good as with monofocal lenses.
• Good night vision: Less impairment at night compared to multifocal lenses.
• Less sensitive to decentration: More tolerant of imperfect positioning in the eye.

Disadvantages

• Limited near vision: Reading glasses may still be required for reading and close-up work.
• Average cost: More expensive than monofocal lenses, but often cheaper than multifocal lenses.
• Technologically newer: Less long-term data available than with monofocal lenses.

Optical side effects

• Moderate halos: Slight ring-shaped light phenomena around light sources, especially at night.
• Slight glare: Moderate glare sensitivity possible.
• Reduced contrast sensitivity: Somewhat reduced contrast vision compared to monofocal lenses, especially in low light.
• Slight adjustment period: Most patients need a few weeks to get used to the new quality of vision.

Multifocal lenses

Advantages

• Comprehensive visual range: offer visual acuity at several distances – far, medium and near.
• Maximum independence from spectacles: Enable a spectacle-free life in most situations.
• Various designs available: Bi-, tri- or quadrifocal options depending on individual requirements.
• Good near vision: Best near vision performance of all lens options.

Disadvantages

• Higher costs: Generally the most expensive option among the three types of lenses.
• Longer neuroadaptive phase: A longer acclimatization period of several months may be required.
• Strict selection criteria: Not suitable for all patients, especially with certain eye diseases.
• Greater restrictions in low light conditions: Greater impairment of night vision.

Optical side effects

• Distinct halos: Pronounced ring-shaped light phenomena around light sources, especially at night.
• Strong glare: Increased sensitivity to glare, especially at night and when driving.
• Reduced contrast sensitivity: Greater reduction in contrast, especially in low light conditions.
• Perception of double vision: In rare cases, dysphotopsia may occur.
• “Waxy vision”: Occasional perception of a kind of “waxy” vision.
• Longer adaptation time: The brain needs more time to process and integrate the different images.

Decision-making factors for patients

Patients should consider the following factors when choosing the right lens:

Lifestyle and professional requirements

• A lot of night driving: Monofocal lenses might be more suitable.
• Intensive computer work: EDOF lenses offer advantages for medium distances.
• Frequent reading or close-up work: multifocal lenses could be ideal.

Expectations of freedom from glasses

• Complete freedom from spectacles desired: Multifocal lenses offer the highest probability.
• Spectacle freedom sufficient for everyday activities: EDOF lenses could provide a good balance.
• Glasses acceptable for certain activities: Monofocal lenses with targeted correction may be sufficient.

Tolerance for optical phenomena

• Sensitive to halos/glare: Monofocal lenses are the least problematic.
• Moderate tolerance: EDOF lenses offer a good compromise.
• High adaptability: Multifocal lenses can be considered.

Eye health

• Pre-existing conditions such as macular degeneration, advanced glaucoma or corneal problems: Monofocal lenses are often the safest choice.
• Healthy eyes without pre-existing conditions: All options can be considered.

Summary: The right way to make a decision

Choosing the optimal intraocular lens is a personal decision that should be based on a detailed consultation with your eye care professional, a thorough eye examination and a realistic assessment of your lifestyle requirements. Patients should understand that each lens type comes with trade-offs:

• Monofocal lenses: Best image quality and contrast vision, but higher spectacle dependency.
• EDOF lenses: Good compromise between extended field of vision and moderate optical side effects.
• Multifocal lenses: Greatest independence from glasses, but with the most pronounced optical side effects.

Open and honest communication about expectations, concerns and potential limitations of each lens option is key to a satisfactory decision and a successful surgical outcome.