Transition Contacts in Action

Paavan Kotini, Mike Matthews, Raj Ganguly, Sam Leu, Jung Lee

The need-Coming Outside

The need- Military

The need- Athletes

• At time uv light can impair actions. The goal of this project is to use previous incumbent technology of transition glasses and apply it to contacts.

General Mechanism of Photochromism

• mechanism over the course of the colour change, the photochromic molecule represented simplistically as two rings.

• Upon the action of UV light or direct sunlight, the structure twists from a perpendicular (closed) form to a flat, planar (opened) structure. This allows the two halves to interact, resulting in the absorption of visible light.

• There are effectively two changes occurring simultaneously; a chemical change arises when the molecule is exposed to UV light, that enables conjugation to take place throughout the molecule; a structural change also occurs to enable the overlap of ∏-orbitals. Therefore, spatially, the molecules must be able to flatten out to allow this conjugation to take place.

• It is a fully reversible reaction so that when the light source is removed, the molecule returns to its uncoloured state. Heat can also help drive the reaction back to the uncoloured form, so in very hot conditions, there is always competition between light and heat to determine the given colour observed. In general, a colour change is still observed, albeit weaker than at room temperature. Similarly, in cold conditions in the presence of sunlight, an intense colour is observed as there is little or no competition from the back reaction.

• Kinetics• This is a cyclic reaction and the number of cycles (or the activation

and fade rates) varies greatly by product. The activation times are generally much shorter than fade times. On average, fade times are two or three times longer than activation times. The Reversacol product range offers a very large variation in kinetics characteristics. Some fade in several seconds, whilst others can take several minutes.

• Systems• As well as the nature of the product influencing the colour and

kinetics result, the system or matrix used with the dye has a strong influence on such properties. For example, in some systems, a colour shift of up to 20nm has been observed.

http://www.photochromics.co.ukJames Robinson Reversacol Photochromic Dyes

Market Research

• Current solutions include: sunglasses, contact lenses with UV protection, and transitioning eyeglasses.

• Each confers benefits to the user, but fails to bridge the gap in technology for low and high intensity situations; or provide an optimum level of convenience.

Market Research

• Since 2002, market reports (e.g Optistock.com) show that the demand for contact lenses has been growing; especially specialty contacts, which currently account for one-third of the world demand for contact lenses.

• Unfortunately these specialty contacts fail to reduce glare in the user’s eyes, making it necessary to use other sun light intensity reducing technologies (e.g sunglasses).

Vision-Corrected Market by Year vs. U.S. Population (Millions) Source: Health Products Research, Inc

Market Research

Nike MAXSIGHT™ lenses by Bausch & Lomb

http://www.bausch.com/us/vision/products/softcontacts/nikemaxsight_faq.jsp

Source: http://www.nike.com/nikebiz/nikebiz.jhtml?page=2&item=maxsight

http://www.flinthillseyecare.com/pdf/Maxsight_Nike_CL.pdf#search='nike%20maxsight'

Market Research

• Possible Cost for production of transition contact lens– Type: Spiro-pyran

• Price: Average $50 per 1g (Sigma Aldrich)

– Type: Spiro-oxazine• Price: $80 per 1g (Sigma Aldrich)

• Selling price of product possibly ranging between $40 to $60 dollars per packet of 20 Contact Lens

• PMMA or polymethylmethacrylate is a clear plastic vinyl polymer that is more transparent than glass.

• PMMA has been used safely for almost 50 years for contact lenses. • Advantages

– Studies with spiropyrans and spiro-oxazines show that it does not slow down UV response times of Photochromic pigments.

– It is also water soluble – It is able to readily bind with the pigment

• Disadvantages– not very gas permeable( very low oxygen penetration)– low elasticity

PMMA Polymethacylate

• An inorganic matrix of silicon dioxide.

• Used in creating current soft contact lenses

• Advantages– It allows the contact lens to

have greater flexibility – Allows for greater oxygen

penetration• Disadvantages

– Is not very compatible with the photochromic pigment

• Slows down transition time• The binding process is

complicated

Silicon Hydro Gel

• [SiO(CH3)2] • Widely used silicon-

based organic polymer

• Optically clear, considered to be inert, non-toxic and non-flammable

Polydimethylsiloxane (PDMS) Elastomer

• Used as backbone for many hydrophilic contact lenses

• 1st to be used in hydrophilic contact lenses

• Very stable and safe material once polymerised

Poly-HEMA

Activation of a Major Photochromic Dye: Spiropyran

• When UV light irradiates spyropyran, one ring opens up and forms conjugated systems, which can absorb visible light.

Activation of a Major Photochromic Dye: Spirooxazine

1′,3′-Dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-

indole] 

•Type: Spiro-pyran•Molecular Weight: 352.4 g/mol•Melting Point: 159 – 162 °C •Price: $40.50 per 1g (Sigma Aldrich)

1′,3′-Dihydro-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole]

• Type: Spiro-pyran• Molecular Weight: 322.36 g/mol• Melting Point: 179-180 °C• Price: $68.40 per 1g (Sigma Aldrich)

1,3-Dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]naphth[2,1-b][1,4]oxazine]

• Type: Spiro-oxazine• Molecular Weight: 328.41 g/mol• Melting Point: 128-130 °C • Price: $19.50 per 250mg / $53.20 per 1g (Sigma

Aldrich)

6,8-Dibromo-1′,3′-dihydro-1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-(2H)-

indole]

• Type: Spiro-pyran• Molecular Weight: 435.15g• Melting Point: 118-120 °C • Price: 48.90 per 1g (Sigma Aldrich)

Spiro[2H-indole-2,2′-[2H]phenanthro[9,10-b](1,4)oxazine],5-chloro-1,3-dihydro-1,3,3-

trimethyl-(9Cl)  

• Type: Spiro-oxazine• Molecular Weight: 412.91 g/mol• Melting Point: 182-186 °C • Price: $90.20 per 1 gram (Sigma Aldrich)

1,3-Dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-

[3H]phenanthr[9,10-b](1,4)oxazine]  

• Type: Spiro-oxazine• Molecular Weight: 378.47 g/mol• Melting Point: 193-195 °C • Price: $104.00 per 1g

5-Methoxy-1,3,3-trimethylspiro[indoline-2,3′-[3H]naphtho[2,1-b]pyran]  

• Type: Spiro-pyran• Molecular Weight: 357.44 g/mol• Melting Point: 152-154 °C • Price: 81.90 per 1g

Manufacturing Techniques

• Encapsulation

• Coating/Binding

• Film Technique

1. Pigmented Spot Size of the Lens: Pupil Size Consideration

Age Diameter of pupil in millimeters

  Daylight Night Difference

20 4.7 8.0 3.3

30 4.3 7.0 2.7

40 3.9 6.0 2.1

50 3.5 5.0 1.5

60 3.1 4.1 1.0

70 2.7 3.2 0.5

80 2.3 2.5 0.2

Pigmented Spot Size = About 10 millimeter

Project Description – Contacts Lens

Dyes propertiesRank Color Wavelength Half Life Strengths

1 Solar Yellow 418 103 20

2 Rush Yellow 429 15 3

3 Sunflower 433 54 16

4 Corn Yellow 449 29 11

5 Flame 470 42 11

6 Ruby 488 33 11

7 Berry Red 494 (421) 81 14

8 Poppy 503 34 5

9 Cardinal 510 56 8

10 Cherry 530 42 5

11 Lilac 550 50 6.2

12 Claret 560 32 12

13 Plum Red 565 23 9

14 Midnight Grey 569 (485) 23 5

15 Amethyst 571 20 6

16 Misty Grey 581 (490) 11 1

17 Storm Purple 589 18 10

18 Palatinate Purple 590 25 21

Dye properties (cont)

Graphite 593 (486) 94 (fast fade) 5

3000 (slow fade)

Oxford Blue 599 8.6 3

Velvet Blue 600 30 7

Aqua Green 617 38 8

Sea Green 618 120 22

Dye selection factors:

•Fast Fade rate

•Higher strength

•Better glare reduction

•Better UV block

Future Direction

1. Manufacture Contact Lens of diameter of about 30mm (Area is about 9 X that of normal contact lens)

2. Learn to do encapsulation technique to encapsulate the pigments/solvent and attach it to contact lens.

3. Test to verify the fade rate, strength, and longevity of different photochromic dyes.

4. Select the dye(s) to be used for our product.

References• http://www.contamac.com/db/display/glossary

• http://www.bimax.com/hema.htm

• http://www.polymer.org.au/uqchem/hydrogels.html

• http://chemweb.calpoly.edu/chem/gragson/Teaching/chem354/Lab_instructions/Photochromism.pdf#search='Spiropyrans'

• http://www.thieme-connect.com/ejournals/pdf/synfacts/doi/10.1055/s-2005-869881.pdf#search='Spiropyrans'

• http://www.freepatentsonline.com/4826977.html(Photochromic spiropyran compounds , United States Patent 4826977)

• http://pubs.acs.org/cgi-bin/abstract.cgi/jpchax/1972/76/i24/f-pdf/f_/j100668a007.pdf?sessid=6006l3

• http://www.photochromics.co.uk/index.htm

References• Lay Gaik Teoha, Jiann Shiehb, Wei Hao Laia, I Ming Hunga, Min Hsiung Hon.

“Structure and optical properties of mesoporous tungsten oxide.” Journal of Alloys and Compounds. (2005) 251–254

• Robert G. Palgrave and Ivan P. Parkin. “Aerosol assisted chemical vapour deposition of photochromic tungsten oxide and doped tungsten oxide thin films.” Journal of Materials Chemistry. 2004, 14, 2864 – 2867

• http://www.freepatentsonline.com/5458815.pdf

• S. Delbaere,a, J.-C. Micheau,b Y. Teral,c C. Bochu,a M. Campredon, c and G. Vermeerscha. “NMR Structural and Kinetic Assignment of Fluoro-3H-naphthopyran Photomerocyanines.”

• www. Alcok.com/intac.html• Andersson, Nina, Alberius, Peter, Ortegren, Jonas, Lindgren, Mikael, and Bergstrom,

Lennart. “Photochromic Mesostructured Silica Pigments Dispersed in Latex Films”