PRESBYOND is usually planned as a binocular blended‑vision treatment, but unilateral surgery may be considered in specific circumstances.
When one-eye treatment may be appropriate
Asymmetry or prior surgery can drive decisions.
- One eye already optimally corrected by previous surgery or naturally
- Lazy eye or reduced potential in one eye limiting its usefulness for blended vision
- Trial of unilateral monovision contact lenses proves comfortable
- Patient prioritises minimal intervention with acceptance of some imbalance
- Surgeon judges that binocular function will remain adequate
Potential drawbacks
Balance and depth perception may be affected.
- Greater risk of symptoms from anisometropia or rivalry between eyes
- Possible reduction in stereopsis and fine depth judgement
- More challenging neuroadaptation than with planned bilateral treatment
- Full discussion and often contact‑lens simulation are recommended first
- Many patients still achieve best performance with bilateral blended vision
