PRESBYOND vs Monovision LASIK: What Is the Difference?

The idea both share

Both treatments accept the same bargain. Instead of correcting both eyes for distance and handing you reading glasses afterwards, they correct one eye for distance and leave the other slightly short-sighted, so that near vision comes from one eye and distance from the other.

The eye that is left short-sighted is not corrected badly. It is corrected to a different target, deliberately, and the brain is expected to combine the two images. This is why the two approaches share most of their advantages and most of their risks: they are the same operation applied to the same idea.

What they do not share is the size of the difference they aim for, or the shape of the treatment applied across the cornea. That is where the useful comparison lives.

Where PRESBYOND differs

Conventional monovision is a strategy rather than a product. The surgeon chooses a target for the non-dominant eye that is short-sighted enough to read with, and accepts that the two eyes see differently. The amount varies widely between surgeons and patients, and some monovision plans are quite conservative while others are pronounced.

PRESBYOND is a branded version of the same strategy on ZEISS equipment, with two additions. The first is a treatment profile the manufacturer describes as non-linear and aspheric, intended to make the correction change gradually across the treatment zone rather than sitting at one uniform value. The second is a planning approach that treats the difference between the eyes as something to be blended across the intermediate range rather than simply tolerated.

Whether that produces a better result for a particular person is not something the published literature answers directly. The studies cited on the results page report outcomes for PRESBYOND patients; they do not randomise those patients against conventional monovision. So the honest claim is narrower than the marketing: this is a more specified plan, not a proven superior one.

Side by side

Depth perception and night vision

Any plan that gives the eyes different focus changes the information the brain uses to judge depth. Most people adapt, and some notice a difference in sport, in parking, or on stairs for a while. The size of the intended difference is the main lever, which is why the plan matters more than the brand.

Night vision is the other shared trade-off. Halos and glare around lights are common early and often settle, and a minority of people notice them in the longer term. If you drive at night for work, or the idea of halos around headlights would be intolerable, that belongs in the consultation rather than in a post-operative complaint. The risks page takes this further.

Screens, sport and driving

Intermediate vision, which is roughly the distance of a laptop screen or a car dashboard, is the range where blended plans are designed to help and where a poorly matched plan is most often noticed. Someone who reads paperbacks for an hour a day and someone who stares at three monitors for nine hours do not need the same plan, and it is reasonable to say so.

Sport matters in two ways: depth perception, and the practical question of whether protective eyewear matters to you. Driving matters in two ways as well: the legal standard for vision, which your clinician and local rules determine, and how comfortable you are with headlights at night.

The contact lens trial

Monovision and blended vision can both be approximated with contact lenses before any surgery. It is not a perfect simulation: a lens sits on the eye rather than reshaping it, and the optics are not identical. But it is the only way to experience a difference between your eyes before it becomes permanent, and it costs a fraction of the operation.

If a clinic offers no way to trial the concept, ask why. There are legitimate answers, including that a particular prescription or ocular surface makes lens wear unsuitable, but the question is worth asking.

Why two surgeons may recommend different options

Because the decision involves judgement as well as measurement. Two careful surgeons can look at the same cornea and choose different target refractions, or disagree about whether a borderline ocular surface should be treated first, or weigh a patient's night driving differently.

That is not evidence that one is wrong. It is a reason to ask what each plan is optimising for, and to be wary of certainty offered before any measurement has been taken.

A decision checklist

These are questions for you rather than for a search engine. The answers do not determine suitability, but they determine whether the trade-offs are worth it.

• How many hours a day do you spend at arm's length from a screen, and at what distance?
• Do you drive at night, professionally or often, and how much do halos worry you?
• Do you play sport or work in a job where depth perception is safety-critical?
• How much would you mind carrying reading glasses for menus, labels and small print?
• Have you worn monovision contact lenses before, and how did you find them?
• Are you making this decision because of a deadline, a discount or a person?

What this comparison cannot tell you