Enter Rx in plus or minus cylinder — auto-transposed to minus-cyl. Vertex reduced from spectacle (12.5 mm) to corneal plane (0 mm) for powers ≥ 4.00 D.
Monovision Trial Targets
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Enter age and manifest refraction to generate trial targets.
⚕Contact-lens trial targets — planning aid only. These are optometric (contact-lens) trial values to demonstrate tolerance. Surgical monovision induces a multifocal corneal profile and is typically tolerated at slightly less minus than the CL trial suggests — do not program a surgical target 1:1 from these numbers. Final candidacy and targets rest with the operating surgeon after a worn trial.
Evans BJW. Monovision: a review. Ophthalmic Physiol Opt 2007;27:417-439. — adapted success 59–67%; night-driving suppression & intermediate gaps are main limits.
Johannsdottir KR, Stelmach LB. Factors in success/failure of monovision. Optom Vis Sci 2001. — distance ghosting, distance stereoacuity, and age predict failure (78% sens / 82% spec).
Reinstein DZ, et al. PRESBYOND / laser blended vision outcomes. — hyperopic monovision succeeds ~77% vs ~95% myopic/emmetropic — basis for the gentler hyperopic staging.
EyeWiki — Monovision LASIK. Staged add targets by presbyopic age; partial monovision when add > +2.00 D.
CRSToday — Ten Monovision Pitfalls. Caution in pilots, drivers, golf/tennis/baseball, fall-risk elderly, and those needing critical stereo.
"Surgical monovision is not optometric monovision" (Healio). Basis for the CL-trial vs surgical-target distinction.
Vertex: Fcl = Fspec / (1 − d·Fspec), d = 0.0125 m, applied per meridian for |power| ≥ 4.00 D.
Astigmatism ≥ 0.75 D degrades trial vision unless corrected; a sphere-only trial under-represents true tolerance (Essential Contact Lens Practice).