OPTOMETRY ยท SEMESTER 1
Lens Forms
Ophthalmic Dispensing Theory
LENS FORMS
Lens Forms
Lens form refers to the specific curvature of a lens's front and back surfaces, which, along with its material, dictates its optical power and how it bends light..
with common forms including
- Convex (curves out),
- Concave (curves in),
- Plano (flat), and
Meniscus (mixed curves)
Convex (Converging): Both surfaces curve outwards, causing light rays to converge (come together).
Concave (Diverging): Both surfaces curve inwards, causing light rays to spread out (diverge).
Plano: One surface is flat (plano), and the other is curved (e.g., plano-convex).
Meniscus: Both surfaces are curved, but one is more curved than the other, creating a lens that can converge or diverge light.
Types of Lens Forms (Examples)
- Biconvex/Equiconvex: Both surfaces are convex (outward).
- Biconcave/Equiconcave: Both surfaces are concave (inward).
- Plano-convex: One flat, one outward-curving.
Plano-concave: One flat, one inward-curving