SPECIAL LENSES

1. Special Lenses in Optometry

2. CONTENTS
1. Special
Lenses
Overview
5. Aniseikonic
Lenses
2. Lenticular
Lenses
6.
Photochromic
Lenses
9. Summary
Table
3. Aspheric
Lenses
7. Polaroid
(Polarized)
Lenses
4. Fresnel
Lenses &
Prisms
8. Tinted
Lenses – Tints
and Filters

3. 01
Special Lenses Overview

4. Special Lenses Overview
Special lenses serve unique optical purposes beyond standard corrections. These lenses address
complex visual needs or enhance wearer comfort and functionality.

5. 02
Lenticular Lenses

6. Description
Designed for very high prescriptions (+10D or higher for
hyperopia, -10D or higher for myopia), lenticular lenses
concentrate the optical power in a central zone (20-30mm
diameter) called the "lenticular" or "aperture" area.

7. Structure
The peripheral part ("carrier") has little or no optical power,
reducing lens thickness and weight significantly compared to
full-power lenses.

8. Purpose
Purpose
Used for patients with aphakia (absence of natural lens),
severe myopia, or hyperopia where regular lenses would
be too thick and heavy.

9. Advantages
Advantage
Reduced lens bulk and weight, improved cosmetics, better comfort, and less distortion around
edges.

10. Challenges
Challenges
Narrow field of clear vision requiring precise fitting and
adaptation period, cosmetic "fried egg" appearance,
limited peripheral correction.

11. Types
Types
Single vision lenticulars, bifocal lenticulars in customized
designs.

12. Materials
Materials
Often combined with high-index materials and aspheric designs to optimize optical quality and
lens profile.

13. Clinical Applications
Clinical applications: Post-cataract surgery without
intraocular lens implantation, extreme prescriptions,
pediatric high prescriptions.

14. 03
Aspheric Lenses

15. Description
These lenses have a non-spherical surface, flattening gradually
towards the periphery.

16. Advantages
Advantages
Thinner, lighter lenses with reduced optical aberrations like spherical aberration.

17. Benefits
Provides better peripheral vision and improved
cosmetics, particularly for high prescriptions.

18. Usage
Used widely for high power prescriptions and progressive addition lenses.

19. 04
Fresnel Lenses & Prisms

20. Description
Fresnel lenses are thin, lightweight lenses made from concentric rings; used often as detachable
lenses or for specific optical effects.

21. Applications
Common in low vision aids and prisms for binocular vision disorders.

22. Features
Fresnel prisms apply prism power in a thin, flexible sheet form, offering an economical and
lightweight option for prism correction.

23. 05
Aniseikonic Lenses

24. Purpose
Designed to compensate for image size differences perceived
by each eye (aniseikonia).

25. Usage
Used especially in patients with large anisometropia or following cataract surgery when one
eye's image size differs significantly.

26. Functionality
These lenses adjust magnification/minification properties
to equalize image size, reducing binocular vision
problems.

27. 06
Photochromic Lenses

28. Description
Lenses that darken automatically upon exposure to UV light
and lighten indoors.

29. Benefits
Provide convenience of sunglasses with normal
eyeglasses, enhancing comfort and UV protection.

30. Features
Available in various materials and combined with anti-reflective coatings.

31. 07
Polaroid (Polarized) Lenses

32. Description
Contain a laminated filter that blocks horizontally polarized
light to reduce glare, particularly from reflective surfaces.

33. Applications
Enhances visual comfort and clarity outdoors, used in
sunglasses for driving, water sports, and snow activities.

34. 08
Tinted Lenses – Tints and Filters

35. Description
Lenses with coloration to reduce light intensity or enhance contrast.

36. Availability
Available in a variety of colors and densities to address visual tasks or aesthetic preferences.

37. Benefits
1
Specific tints can improve contrast for certain conditions
(e.g., yellow or amber for low-light environments).
2
Filters selectively absorb certain wavelengths, useful in
occupational or recreational settings.

38. 09
Summary Table

39. Lens Type Key Characteristics Primary Uses & Benefits Challenges/Considerations
Lenticular Central high power zone,
peripheral carrier lens
High prescriptions, aphakia,
post-cataract correction
Narrow view, bulky
appearance, limited peripheral
power
Aspheric Non-spherical surface for
reduced aberration
High prescriptions,
progressives, aesthetics
Cost higher than spherical,
fitting precision needed
Fresnel Lenses & Prisms Thin concentric rings,
detachable, lightweight
Low vision aids, prism
correction
Reduced image quality, visible
ring patterns
Aniseikonic Magnification control to
equalize image size
Anisometropia correction,
binocular vision
Complex customization, may
require adaptation
Photochromic UV responsive darkening Convenience of sunglasses +
specs, UV protection
Reaction speed depends on
conditions
Polaroid (Polarized) Filter horizontal glare Outdoor use, glare reduction,
visual comfort
Not effective in all situations
Summary Table

40. Thank You