Which type of lens typically has more plus power for the same refractive error: spectacle lenses or contact lenses?

• A. Spectacle lenses
• B. Contact lenses
• C. Both equally
• D. Depends on prescription

Answer: (B)

Vertex distance changes how much power actually reaches the eye. Spectacle lenses sit several millimeters from the cornea, while contact lenses ride directly on the cornea. For a hyperopic error (plus power), the same lens value delivers a slightly different effect at the eye because of that distance. The eye effectively receives a little more power from a given spectacle, so to achieve the same retinal correction you would prescribe a slightly lower plus power for spectacles than the lens’s nominal value. Contact lenses, being on the cornea, provide the full power at the eye, so for the same refractive error they tend to require more plus power than spectacles. That’s why contact lenses typically have more plus power.