Unit 1 Flashcards

(35 cards)

1
Q

beggining Leonardo DaVinci

A

-Described a method of directly altering corneal power
–By immersing the eyeball in a bowl of water
◦ Controversial topic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

beggining Rene Descartes

A

◦ Fluid filled tube on the eye
◦ While impractical, the principle of directly neutralizing corneal power is consistent with the principles underlying modern contact lens design
* Contact lens name origin
◦ In “contact” with the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

beginning Thomas Young

A

◦ Constructed a “fluid-filled eyecup”
◦ Similar system to that used by Descartes
◦ He did not intend the device to be used for correction of refractive errors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

1800- * Sir John Herschel

A

◦ Proposed ‘taking a mould of the cornea and impressing it on some transparent medium’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

1800- * F.A. Muller

A

◦ Manufacturers of prosthetic eyes
◦ Described the fitting of a partially transparent shell of thin clear blown glass to a patient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

1800- * Eugene Kalt (French ophthalmologist)

A

Fit thin glass shells for keratoconus patients and obtained significant improvement in vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

1800- * August Muller

A

Credit for fitting the first powered contact lens
◦ Described the correction of his own high myopia with a contact lens
-Lens was made by optical engineer, Karl Otto Himmler
-First manufacturer of optically ground contact lenses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

early 1900- * Carl Zeiss Company

A

Applied for a patent proposing the manufacture of contact lenses from ‘cellon, celluloid, or similar organic substance…’
◦ First to cut lenses from moulds
◦ Diagnostic lenses (trial lens set)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

early 1900- * Joseph Dallos

A

◦ Refined fitting and moulding techniques
◦ Went on to develop techniques for taking impressions of the human eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

1930- * PMMA (polymethyl methacrylate)

A

◦ Moulded or lathe cut
◦ Difficult to break, lighter than glass
◦ NOT oxygen permeable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

1930- * William Feinbloom

A

◦ Combined PMMA with glass (centre)
* Large glass contact lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  • Dallos (1946)
A

◦ Fenestration (putting little holes, helps w/ oxygen permeability)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

1940- * Large plastic contact lenses

A

Contact Lenses (1948)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
  • Kevin Tuohy (1948)
A

-Credited with the first PMMA corneal contact lens
-Error during the lathing of a PMMA scleral lens (haptic and corneal portions separated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  • Tanaka (1950)
A

◦ PMMA corneal lens in Japan
◦ Developed a machine to make lenses
◦ Precursor to Menicon contact lens company

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  • Joseph Soper (1950s and 60s)
A

◦ Smaller diameter corneal lenses
◦ Soper keratoconus lens

17
Q

1960s and 1970s- * Norman Gaylord

A

Incorporated silicone into the basic PMMA structure
◦ Patented oxygen permeable lenses (gas permeable lenses)

18
Q

1960 and 1970- * Otto Wichterle

A

◦ Unable to attract support…Wichterle conducted experiments in his own home
-Developed the spin-casting technique
◦ Invented soft contact lenses
◦ HEMA material (hydroxyethyl methacrylate)

19
Q

1960-1970- * Bausch & Lomb

A

◦ Acquired the patent to develop soft contact lenses commercially in the USA
◦ Introduced soft lenses into the world market in 1972

20
Q

1980s- * Toric soft contact lenses

A

correct astigmatism

21
Q

1980- Silicone lenses

A

◦ Oxygen permeability
◦ Extended wear

22
Q

1980 CL

A
  • Bifocal soft contact lenses
    • Coloured contact lenses
  • Disposable contact lenses (daily)
23
Q

1980- disposable lenses

A

◦ In the early days, patients would typically use the same pair of lenses…until they couldn’t

24
Q

what did Klas Nilsson of Gorthenburd, sweden do??

A

convinced patients of the benefits of 6-month replacement frequency

25
Gothenburg study’
proved the benefits of regular lens replacement
26
◦ ‘Danalens’
low-cost, multiple individual lens packs -First truly disposable lens -Purchased by Johnson & Johnson in 1984 -Acuvue lens!
27
1990- * Daily disposable contact lenses
◦ ‘Premier’ daily disposable launched in the UK in 1994 ◦ Johnson & Johnson released the ‘1-Day Acuvue’ around the same time ◦ CIBA Vision entered the daily disposable lens market in 1997 with ‘Dailies’ -More disposable options
28
* Silicone Hydrogel Lenses (1998)
◦ Focus Night & Day (CIBA Vision) ◦ Purevision (Bausch & Lomb) * The introduction of these lenses is considered to be the most significant advance in contact lens material technology since the development of HEMA by Wichterle
29
The future
* Convenience and ocular health benefits of daily disposable lenses are likely to increase in popularity * Silicone hydrogels are set to continue as the main material from which lenses are fabricated ◦ However, the possibility of a new lens material should not be discounted * Likely to be used increasing for the correction of presbyopia (refractive error for middle-aged & older adults to see things up close) * Extended wear is unlikely to break through the ‘glass ceiling’
30
more of the future
* Anti-myopia designs * Anti-infective and anti-inflammatory lenses (medications released into the eye) * Glucose monitoring * Intraocular pressure measurement * Digital information acquisition and display (e.g. a contact lens version of Google Glass)
31
Soft Lens Manufacture
* Lathe cutting * Spin casting * Cast moulding
32
Lathe cutting
* More expensive * Custom lenses ◦ High spherical and/or toric powers, keratoconus * Polymer button * Diamond tipped tool ◦ Back surface lathed first ◦ Front surface lathed * Inspection -> hydration -> re-inspection * Inserted into vial * Autoclaved to effect sterilization
33
Spin casting
* Stainless steel convex tool produced * Plastic concave mould formed * Liquid plastic monomer added to spinning concave mould * UV radiation to initiate lens polymerization * Edge polished * Inspection -> hydration -> inspection * Inserted into blister pack containing saline * Autoclaved
34
Cast Moulding
* Stainless steel concave and convex tools produced * Plastic concave and convex moulds formed * Liquid plastic monomer added to concave plastic mould * Plastic moulds clipped together * Contact lens forms in between moulds * UV radiation to initiate lens polymerization * Inspection -> hydration -> inspection * Inserted into blister pack containing saline * Autoclaved
35
Cast Moulding
* Most common ◦ Very consistent production ◦ Do not need to polish ◦ Lower cost ◦ Efficient * Also called injection moulding