Night halos and intraocular lenses: The truth about the side effects of premium lenses

Night halos and intraocular lenses: The truth about the side effects of premium lenses

Undergoing cataract or presbyopia surgery is an important decision that can significantly improve both your vision and your quality of life. Today, technology allows us to go far beyond simply removing the cloudy natural lens. With Premium intraocular lenses (trifocal or EDOF), we can provide patients with near-complete independence from glasses for both distance and near vision.

However, before coming to the clinic, many patients search online for information and repeatedly come across the same concern: night halos and other visual phenomena. As an ophthalmic surgeon, I believe it is important to discuss these issues with complete transparency. How common are they? Are they permanent? Can they be minimized?

What are night halos and dysphotopsias?

After surgery, patients typically describe two types of light-related visual phenomena:

• Halos: Rings of light surrounding bright light sources, such as car headlights or streetlights.
• Glare: Bright rays, streaks, or scattered light extending from a light source, particularly in low-light or nighttime conditions.

Experiencing these effects does not mean that the surgery has failed or that there is damage to the eye. Rather, they are an optical consequence of the design of certain premium intraocular lenses, which are engineered to provide clear vision at multiple distances.

Why do halos occur?

Trifocal intraocular lenses use a diffractive optical design. Tiny concentric rings divide incoming light so the eye can focus at far, intermediate, and near distances simultaneously. When the pupil dilates at night, light passes through these rings and may be perceived as halos around bright light sources.

EDOF (Extended Depth of Focus) lenses work differently. Instead of splitting light into multiple focal points, they create a continuous extended focus. As a result, the incidence of night halos is significantly lower—almost imperceptible for most patients—although near vision is usually slightly less powerful than with trifocal lenses.

To better understand the differences between these optical designs, we invite you to explore our lens simulator, where you can compare both nighttime halos and the reading performance of each type of intraocular lens.

The key to the process: What is neuroadaptation and how long does it take?

One of the most common questions I hear in the clinic is: “Doctor, will I see these halos forever?”

The answer is no—not with the same intensity. In the vast majority of patients, the brain gradually adapts until these visual phenomena become barely noticeable or are no longer consciously perceived.

This process is called neuroadaptation. While the eye captures images, it is the brain that interprets them. After implantation of a Premium intraocular lens, the visual system must learn to process light in a new way. During the first few months, the brain gradually filters out these unnecessary visual signals.

• First few weeks: Halos are usually most noticeable, especially while driving at night.
• Between 3 and 6 months: The brain becomes increasingly efficient at suppressing these visual phenomena, making them much less noticeable.
• Long term: Most patients with trifocal lenses resume completely normal daily activities, drive comfortably at night, and value their freedom from glasses far more than this mild and temporary nighttime visual effect.

How can these effects be minimized?

There is no single “best” intraocular lens for everyone. The ideal lens is the one that best matches each patient’s eyes, lifestyle, and visual priorities. Careful preoperative evaluation is the key to achieving the best possible outcome.

• Lifestyle: For professional drivers, people who frequently drive at night, or those who prioritize nighttime vision, an EDOF or enhanced monofocal lens is often a more suitable choice than a trifocal lens.
• Overall eye health: Severe dry eye, certain retinal conditions, or early glaucoma can reduce visual quality. In these cases, simpler optical designs often provide safer and more predictable results.
• Honest preoperative counseling: Knowing what to expect after surgery reduces postoperative anxiety and facilitates the neuroadaptation process.

Conclusion

Night halos are a real phenomenon, but they should not discourage patients from considering a technology that can dramatically reduce dependence on reading glasses. With careful patient selection and honest medical counseling, cataract surgery with Premium intraocular lenses achieves very high levels of patient satisfaction.

If you are considering cataract or presbyopia surgery in Girona, we invite you to schedule a personalized consultation to determine which intraocular lens is best suited to your needs.