Contact Lens > CL Manufacturing > Flashcards

CL Manufacturing Flashcards

(22 cards)

Study These Flashcards
1
Q

SCL methods

A
  • lathe cutting
  • spin casting
  • cast mould
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Combination methods

A
  • moulding + lathing
  • spin casting + lathing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is lathe cutting

A
  • Anhydrous button is lathed in a controlled atmosphere
  • button mounted on a spinning shaft, and shaped with a computer cutting tool
  • lens is then removed and hydrated to soften it, and then sealed in saline
  • autoclaved at 121 degrees for 15 mins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Lathe cutting advantages

A
  • few limitations of Rx
  • established for CL manufacturing
  • easily adapted for CL manufacturing
  • reserved for customer extreme ranges
  • suitable for most materials
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Lathe cutting disadvantages

A
  • increased cost
  • time consuming
  • variable surface finish
  • strict humidity control
  • cleaning/polishing required
  • lenses must be soaked
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is spin casting

A
  • liquid monomers poured into mould
  • mould is spun in controlled environment
  • rotation velocity/surface tension/gravity defines the back curvature (BVP)
  • mould shape defines front surface
  • UV light applied to polymerase monomers
  • edges then buffed and polished
  • lens hydrated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Spin casting advantages

A
  • very smooth back surface
  • back surface matches corneal profile
  • least likely to produce surface defects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Spin casting disadvantages

A
  • slower and more complex
  • more expensive
  • not as scalable as moulding
  • requires polishing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is injection moulding (cast mould)

A
  • monomers injected into cast a high pressure
  • UV light or heat initiates polymerisation, then lenses removed
  • lenses are then hydrated to soften
  • lenses are verified, packaged and sterilised in same way as spin casting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Injection moulding advantages

A
  • very quick
  • low costs
  • easy to produce
  • many lenses at once
  • most widely used
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Injection moulding disadvantages

A
  • strict environmental control
  • expensive equipment
  • number of moulds limits parameters
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

RGP manufacturing

A
  • lathe cutting
  • cast moulding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

RGP lathe cutting

A
  • similar to SCL
  • reduced margin of error
  • separately configured lathes for front and back surface
  • engraving/marking is common on RGP lenses stored dry
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

RGP cast moulding

A
  • Similar to soft lens material
  • lens left to dry
  • mould broken apart and lens revealed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Toric manufacturing

A
  • dual axis lathing on stationary lens
  • can produce any shape
  • blank lens is crimpled across the front surface, then worked into a sphere, releasing the crimpling leaving a toric surface
  • moulding requires a separate mould for each Rx
  • dual axis flying cutter, the cutter set to particular axis as this passes by the rotating lens button it creates the toric shape
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Toric manufacturing - stabilisation methods

Study These Flashcards
A

Prism ballast
- 1 or 1.5 base down prism traditionally
- balances the thickness profile to minimise rotational effects
- RGP and SCLs
- produced by software

Dynamic stabilisation
- dual thin zones or double slab off top and bottom portions of the lens
- truncation rarely used
- removing 1/1.5mm chord from the lower eye
- excellent stabilising but can be uncomfortable

17
Q

Multi focal manufacturing

Study These Flashcards
A

Segmented design
- 2/3 portions make up an alternating lens, can be fused or solid portions with a range of segmented shapes
- stabilised with prism or truncation
- more commonly RGP

Simultaneous vision
- concentric rings of diffractive pattern are moulded onto lens back surface

Hybrid CL
- similar process to lathe cut soft contact lenses
- plastic discs cut with the lathe have a rigid centre, surrounded by non-hydrated SCL material
- the 2 materials are bonded together with prepriatary techniques to prevent separation of materials

Scleral CL
- lathe cutting
- production as for CL, plus cutting of scleral portion
- take mould of the eye and scleral topography to measure shape

18
Q

Types of tints

Study These Flashcards
A
  • handling tint
  • therapeutic tint
  • cosmetic
  • dyslexia
  • prosthetic
  • sport
  • theatric
19
Q

Types of translucent tints

Study These Flashcards
A
  • dye dispersion
  • vat dye testing
  • chemical bonding tint
  • printing
20
Q

Types of opaque tints

Study These Flashcards
A
  • dot matrix tint
  • laminate
21
Q

Quality assurance in RGPs

Study These Flashcards
A
  • inspection with 10x mag
  • power
  • BOZR
  • TD
  • optic zone diameter
  • lens thickness
  • cleaned and dispatched
22
Q

Quality assurance of SCLs

Study These Flashcards
A
  • inspected dry
  • hydrated
  • inspected wet
  • packaged
  • autoclaved
  • dispatched
Contact Lens
flashcards
Decks in class (18)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions