logging in or signing up Introduction to Contact Lenses RAJNISHKISHORE Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 190 Category: Education License: All Rights Reserved Like it (4) Dislike it (0) Added: September 20, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: mousumioptom (10 month(s) ago) hello sir.i have gone through ur ppt. its a informative one. kindly allow me to download.my id- liveleo.mou@gmail.com Saving..... Post Reply Close Saving..... 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Edit Comment Close Premium member Presentation Transcript Introduction to Contact Lenses : 1 Introduction to Contact Lenses Objectives : 2 Objectives Uses of Contact Lenses History, Evolution, Types & Classifications Physical Properties of SCL Materials Oxygen Performance Water Content & FDA classifications Materials & Manufacturing methods Introduction to B&L CL Portfolios & Manufacturing Plants Uses of Contact Lenses : 3 Uses of Contact Lenses Uses & Benefits of Contact Lenses : 4 Uses & Benefits of Contact Lenses Unrestricted peripheral field Real image size & no reflections More convenient More natural appearance Correct medical conditions (keratoconus) Protect cornea (Bandage Lens) Drug Delivery Uses of Contact Lens : 5 Uses of Contact Lens Purpose Contraindications for Lens Wear : 6 Contraindications for Lens Wear Inflammation / infection Chronic ocular allergy Certain systemic diseases Ptosis Corneal hyposensitivity Poor & inadequate tear film Occupational incompatibility Noncompliant, unmotivated patient Poor patient hygiene History, Evolution, Types & Classifications : 7 History, Evolution, Types & Classifications History : 8 History 1508 Leonardo da Vincci described it. 1938 - Muller & Obrig developed first scleral CL (PMMA) 1948 - Kevin Touhy developed first corneal CL (PMMA) 1950’s - Otto Wichterle developed first soft CL (HEMA) 1980’s - RGP & Soft torics introduced 1999 - Silicone Hydrogel introduced (2nd generation SCL) Otto Wichterle and B&L : 9 Otto Wichterle and B&L Developed HEMA - Hydroxyethyl methacrylate HEMA - plastic material which absorbs water. B&L acquired the rights in 1960’s. B&L first to manufacture & distribute soft CL in 1971 Evolution of Contact Lens : 10 Evolution of Contact Lens PMMA 40s 50s 60s 70s 80s 90s 2000 Advantages & Disadvantages- Soft Contact Lens : 11 Advantages & Disadvantages- Soft Contact Lens Advantages: Comfortable Very short adaptation Able play contact sports Less sensitive to dust Disposable available - health & hygiene Short chair time Disadvantages: Care regimen important Attracts deposits easily Shorter life-span (~ 1 yr) Lower Dk than RGP Lens dryness possible Modalities : 12 Modalities Contact Lenses Traditional Planned Replacement/ Disposable Daily (Disp) Bi-weekly Monthly Quarterly Traditional : 13 Traditional Modality of choice for some new wearers & toric (price sensitive) Lens care regiment important - cleaning, disinfecting & protein removal Life span should not be more than 1 years Eg. B&L Optima 38, B/U/HO4 PRD Contact Lens : 14 PRD Contact Lens Modality of choice now (~ 70% of SCL users) Price no longer a factor today Toric PRD also available Wear lens for prescribed period & throw away Health & hygiene factor Less care regiment required Disposable Contact Lens : 15 Disposable Contact Lens Daily : ‘True’ Disposable for one time use Occasional wear ideal No care solution (lens lubricant only) Highest cost of all disposable (full-time) Eg. B&L Soflens Daily Disposable PRD Contact Lens : 16 PRD Contact Lens Bi-weekly / Monthly/ Quarterly : Lens thrown after a short period More economical than daily Ideal for full time users Lens care required Eg: SofLens 59, SofLens 38, SofLens Toric, PureVision Another way of classification : 17 Another way of classification Daily Wear: Extended Wear: Continuous Wear: Wear day time / no sleep. Sleep up to 6 nights. Sleep with CL up to 29 night. Physical properties of CL material : 18 Physical properties of CL material Physical properties of CL material : 19 Oxygen Performance Water Content, ionic charges & FDA classification Protein uptake / deposition Tensile strength / Lens handling Biocompatibility Cytotoxicity Resistance to microbial growth Dimensional stability Wettability Physical properties of CL material Oxygen Performance : 20 Oxygen Performance Oxygen depends on Water content of the material Lens design Monomer selection Measures of oxygen performance: Dk = oxygen permeability Dk/t = oxygen transmissibility Overnight corneal swelling Oxygen Flux Slide 21: 21 Dk - Oxygen Permeability. Amount of O2 material allow through Dk/t - Oxygen Transmissibility. Amount of O2 material of certain thickness allow through Oxygen Performance Overnight Corneal Swelling : 22 Overnight Corneal Swelling Most valid of real-life clinical performance Measures % of corneal thickness increase (swelling) 2 - 4% normal without lens 8 - 12% conventional extended wear hydrogel lenses 2 - 4% silicone hydrogel lenses >7% is considered as danger zone Oxygen Performance Slide 23: 23 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 % edema 77% >7% is considered as danger zone Oxygen Performance Oxygen Requirement for CL Wear : 24 Oxygen Requirement for CL Wear Holden - Mertz Criteria (1984) Dk/t required for DW = 24 x 10-9 Dk/t required for EW = 87 x 10-9 Oxygen Performance Slide 25: 25 Oxygen Performance Oxygen Flux Vs Dk/t Slide 26: 26 Water Content Low Water (< 50%) High Water (50% or more) Material Types. Ionic Non-ionic FDA Classification Group I, II, III, IV Water content, ionic charges & FDA classification Nonionic/Ionic Base Monomers : 27 Nonionic/Ionic Base Monomers Water content, ionic charges & FDA classification Low Water Materials : 28 Low Water Materials Adequate physiological response Low protein deposition High tensile strength Compatible with all lens care systems Manufactured using lathe-cut, RPIII, spincast or cast mold processes Water content, ionic charges & FDA classification High Water Materials : 29 High Water Materials Moderate oxygen permeability Lower tensile strength Tend to absorb protein Greater dehydration potential Water content, ionic charges & FDA classification Pervaporation Rates : 30 Pervaporation Rates Water content, ionic charges & FDA classification Silicone Hydrogel Materials : 31 Silicone Hydrogel Materials Oxygen via silicone low water, high Dk Supports healthy continuous wear Slide 32: 32 Ionic - lens is ‘charged’ (usually negative) Non Ionic - lens is ‘neutrally charged’ * charge used for attracting water into lens, thus most older high water content are ionic. Water content, ionic charges & FDA classification FDA Classification : 33 FDA Classification Group Water Content Charge I Low Non Ionic II High Non Ionic III Low Ionic IV High Ionic Water content, ionic charges & FDA classification Protein uptake : 34 Protein uptake Other Physical Properties (1) : 35 Tensile strength / Lens handling Biocompatibility Cytotoxicity Resistance to microbial growth Other Physical Properties (1) Slide 36: 36 Dimensional stability Wettability Other Physical Properties (2) CL Manufacturing Methods : 37 CL Manufacturing Methods Spin Casting Lathe Cut Reverse Process III (RP III) Cast Moulding Spin Casting (SQ, B/U/O) : 38 Spin Casting (SQ, B/U/O) Developed by Otto Wichterle Liquid monomer is injected to a spinning mould. UV light used to hardened (polymerization) Lens edge is polished. Lens is hydrated, packaged & sterilized. Lathe Cut : 39 Lathe Cut Blanks buttons made. Buttons placed onto a diamond tool lathe and rotated at high speed Polymer cut away and produces a precise lens surface Front & back surface are polished, hydrated, packaged & sterilized. Eg. Optima Toric Reverse Process III : 40 Reverse Process III Combination Spin Cast & Lathe Cut Front Surface Spin Cast & Back Surface Lathe Cut. Best of both process. Eg. Optima 38 SofLens 38 Cast Molding : 41 Cast Molding Latest technology. Liquid monomer is injected to front mould (‘female mould’). Back mould (‘male mould’) is clamped & UV light used to polymerized lens. Lens removed, hydrated, package & sterilized. Manufacturing Process Mold production Lens casting Lens hydration Inspection/packing CL Parameters : 42 CL Parameters Base Curve Curve of the posterior central optic zone. Diameter Max. external dimension of lens. Optic Zone Central optic portion. Saggital depth (sag) Distance from outer edge of lens to lens centre Base Curve & Sag : 43 Base Curve & Sag Thank you : 44 Thank you You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
Introduction to Contact Lenses RAJNISHKISHORE Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 190 Category: Education License: All Rights Reserved Like it (4) Dislike it (0) Added: September 20, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: mousumioptom (10 month(s) ago) hello sir.i have gone through ur ppt. its a informative one. kindly allow me to download.my id- liveleo.mou@gmail.com Saving..... Post Reply Close Saving..... Edit Comment Close By: RAJNISHKISHORE (12 month(s) ago) send me ur email id in rajnish.8452gmail.com i will mail u all Saving..... Post Reply Close Saving..... Edit Comment Close By: drasma07 (14 month(s) ago) kindly allow to upload Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Introduction to Contact Lenses : 1 Introduction to Contact Lenses Objectives : 2 Objectives Uses of Contact Lenses History, Evolution, Types & Classifications Physical Properties of SCL Materials Oxygen Performance Water Content & FDA classifications Materials & Manufacturing methods Introduction to B&L CL Portfolios & Manufacturing Plants Uses of Contact Lenses : 3 Uses of Contact Lenses Uses & Benefits of Contact Lenses : 4 Uses & Benefits of Contact Lenses Unrestricted peripheral field Real image size & no reflections More convenient More natural appearance Correct medical conditions (keratoconus) Protect cornea (Bandage Lens) Drug Delivery Uses of Contact Lens : 5 Uses of Contact Lens Purpose Contraindications for Lens Wear : 6 Contraindications for Lens Wear Inflammation / infection Chronic ocular allergy Certain systemic diseases Ptosis Corneal hyposensitivity Poor & inadequate tear film Occupational incompatibility Noncompliant, unmotivated patient Poor patient hygiene History, Evolution, Types & Classifications : 7 History, Evolution, Types & Classifications History : 8 History 1508 Leonardo da Vincci described it. 1938 - Muller & Obrig developed first scleral CL (PMMA) 1948 - Kevin Touhy developed first corneal CL (PMMA) 1950’s - Otto Wichterle developed first soft CL (HEMA) 1980’s - RGP & Soft torics introduced 1999 - Silicone Hydrogel introduced (2nd generation SCL) Otto Wichterle and B&L : 9 Otto Wichterle and B&L Developed HEMA - Hydroxyethyl methacrylate HEMA - plastic material which absorbs water. B&L acquired the rights in 1960’s. B&L first to manufacture & distribute soft CL in 1971 Evolution of Contact Lens : 10 Evolution of Contact Lens PMMA 40s 50s 60s 70s 80s 90s 2000 Advantages & Disadvantages- Soft Contact Lens : 11 Advantages & Disadvantages- Soft Contact Lens Advantages: Comfortable Very short adaptation Able play contact sports Less sensitive to dust Disposable available - health & hygiene Short chair time Disadvantages: Care regimen important Attracts deposits easily Shorter life-span (~ 1 yr) Lower Dk than RGP Lens dryness possible Modalities : 12 Modalities Contact Lenses Traditional Planned Replacement/ Disposable Daily (Disp) Bi-weekly Monthly Quarterly Traditional : 13 Traditional Modality of choice for some new wearers & toric (price sensitive) Lens care regiment important - cleaning, disinfecting & protein removal Life span should not be more than 1 years Eg. B&L Optima 38, B/U/HO4 PRD Contact Lens : 14 PRD Contact Lens Modality of choice now (~ 70% of SCL users) Price no longer a factor today Toric PRD also available Wear lens for prescribed period & throw away Health & hygiene factor Less care regiment required Disposable Contact Lens : 15 Disposable Contact Lens Daily : ‘True’ Disposable for one time use Occasional wear ideal No care solution (lens lubricant only) Highest cost of all disposable (full-time) Eg. B&L Soflens Daily Disposable PRD Contact Lens : 16 PRD Contact Lens Bi-weekly / Monthly/ Quarterly : Lens thrown after a short period More economical than daily Ideal for full time users Lens care required Eg: SofLens 59, SofLens 38, SofLens Toric, PureVision Another way of classification : 17 Another way of classification Daily Wear: Extended Wear: Continuous Wear: Wear day time / no sleep. Sleep up to 6 nights. Sleep with CL up to 29 night. Physical properties of CL material : 18 Physical properties of CL material Physical properties of CL material : 19 Oxygen Performance Water Content, ionic charges & FDA classification Protein uptake / deposition Tensile strength / Lens handling Biocompatibility Cytotoxicity Resistance to microbial growth Dimensional stability Wettability Physical properties of CL material Oxygen Performance : 20 Oxygen Performance Oxygen depends on Water content of the material Lens design Monomer selection Measures of oxygen performance: Dk = oxygen permeability Dk/t = oxygen transmissibility Overnight corneal swelling Oxygen Flux Slide 21: 21 Dk - Oxygen Permeability. Amount of O2 material allow through Dk/t - Oxygen Transmissibility. Amount of O2 material of certain thickness allow through Oxygen Performance Overnight Corneal Swelling : 22 Overnight Corneal Swelling Most valid of real-life clinical performance Measures % of corneal thickness increase (swelling) 2 - 4% normal without lens 8 - 12% conventional extended wear hydrogel lenses 2 - 4% silicone hydrogel lenses >7% is considered as danger zone Oxygen Performance Slide 23: 23 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 % edema 77% >7% is considered as danger zone Oxygen Performance Oxygen Requirement for CL Wear : 24 Oxygen Requirement for CL Wear Holden - Mertz Criteria (1984) Dk/t required for DW = 24 x 10-9 Dk/t required for EW = 87 x 10-9 Oxygen Performance Slide 25: 25 Oxygen Performance Oxygen Flux Vs Dk/t Slide 26: 26 Water Content Low Water (< 50%) High Water (50% or more) Material Types. Ionic Non-ionic FDA Classification Group I, II, III, IV Water content, ionic charges & FDA classification Nonionic/Ionic Base Monomers : 27 Nonionic/Ionic Base Monomers Water content, ionic charges & FDA classification Low Water Materials : 28 Low Water Materials Adequate physiological response Low protein deposition High tensile strength Compatible with all lens care systems Manufactured using lathe-cut, RPIII, spincast or cast mold processes Water content, ionic charges & FDA classification High Water Materials : 29 High Water Materials Moderate oxygen permeability Lower tensile strength Tend to absorb protein Greater dehydration potential Water content, ionic charges & FDA classification Pervaporation Rates : 30 Pervaporation Rates Water content, ionic charges & FDA classification Silicone Hydrogel Materials : 31 Silicone Hydrogel Materials Oxygen via silicone low water, high Dk Supports healthy continuous wear Slide 32: 32 Ionic - lens is ‘charged’ (usually negative) Non Ionic - lens is ‘neutrally charged’ * charge used for attracting water into lens, thus most older high water content are ionic. Water content, ionic charges & FDA classification FDA Classification : 33 FDA Classification Group Water Content Charge I Low Non Ionic II High Non Ionic III Low Ionic IV High Ionic Water content, ionic charges & FDA classification Protein uptake : 34 Protein uptake Other Physical Properties (1) : 35 Tensile strength / Lens handling Biocompatibility Cytotoxicity Resistance to microbial growth Other Physical Properties (1) Slide 36: 36 Dimensional stability Wettability Other Physical Properties (2) CL Manufacturing Methods : 37 CL Manufacturing Methods Spin Casting Lathe Cut Reverse Process III (RP III) Cast Moulding Spin Casting (SQ, B/U/O) : 38 Spin Casting (SQ, B/U/O) Developed by Otto Wichterle Liquid monomer is injected to a spinning mould. UV light used to hardened (polymerization) Lens edge is polished. Lens is hydrated, packaged & sterilized. Lathe Cut : 39 Lathe Cut Blanks buttons made. Buttons placed onto a diamond tool lathe and rotated at high speed Polymer cut away and produces a precise lens surface Front & back surface are polished, hydrated, packaged & sterilized. Eg. Optima Toric Reverse Process III : 40 Reverse Process III Combination Spin Cast & Lathe Cut Front Surface Spin Cast & Back Surface Lathe Cut. Best of both process. Eg. Optima 38 SofLens 38 Cast Molding : 41 Cast Molding Latest technology. Liquid monomer is injected to front mould (‘female mould’). Back mould (‘male mould’) is clamped & UV light used to polymerized lens. Lens removed, hydrated, package & sterilized. Manufacturing Process Mold production Lens casting Lens hydration Inspection/packing CL Parameters : 42 CL Parameters Base Curve Curve of the posterior central optic zone. Diameter Max. external dimension of lens. Optic Zone Central optic portion. Saggital depth (sag) Distance from outer edge of lens to lens centre Base Curve & Sag : 43 Base Curve & Sag Thank you : 44 Thank you