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SOFT LENS MATERIAL FITTING & FOLLOW-UP EVALUATION University of Missouri-St. Louis College of Optometry.

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Presentation on theme: "SOFT LENS MATERIAL FITTING & FOLLOW-UP EVALUATION University of Missouri-St. Louis College of Optometry."— Presentation transcript:

1 SOFT LENS MATERIAL FITTING & FOLLOW-UP EVALUATION University of Missouri-St. Louis College of Optometry

2 Advantages Initial comfort Little lag Simple to fit Inventory Quick adaptation Occasional wear Hard to dislodge Difficult to get trapped FB Rarely causes tearing Cosmesis

3 Disadvantages Bacterial contamination/greater risks with noncompliance Care? Durability Prone to deposits Reduced oxygen permeability with hydrogel materials Quality of vision Difficult to verify Limitations of correction

4 Materials Chemical monomers linked to form chains of polymers, cross-linked loosely polyHema Add other monomers to improve HEMA MAA, MMA, GMA, PVA Silicone Hydrogels

5 Monomer Characteristics HEMA – hydrophilic, soft, wettable, low Dk EGDMA – Stable, low Dk MAA – hydrophilic, pH sensitive MMA – Hard, no Dk, machinable, optical clarity, stable NVP – Hydrophilic, wettable, high water uptake, High Dk, pH sensitive

6 Monomer Characteristics GMA – Wettable, deposit resistant, low Dk PVA – Hydrophilic, high water uptake, Deposit resistant Silicone – hydrophobic, High Dk

7 The Science Behind the Lenses HEMA-based materials –Positives Easily fabricated into CL’s Relatively cheap to produce Highly flexible Dimensionally stable to changes in pH & temp. –Negatives Reliance on H 2 O to transport O 2 –Limitation to amount of O 2 transmitted to cornea –Corneal oxygen deficiency 2006-01-0004

8 O 2 transport – HEMA materials 2006-01-0004

9 Silicone Hydrogels Available Focus Night & Day O2 Optix & Air Optix Aqua AV Advance AV Oasys PureVisionBiofinity Material Lotrafilcon A Lotrafilcon BGalyfilcon A Senofilcon A Balafilcon AComfilcon A Dk14011060103101128 Dk/t17513886147110160 Water content 24%33%47%38%36%48% Powers+6 to -10 +8 to -12 +6 to -12-0.25to -10 BCR8.4, 8.68.68.3, 8.78.4, 8.88.3, 8.68.6 ReplaceMonthly2-4 weeks2 weeks Monthly

10 Silicone Hydrogels Available AvairaO2 Optix Custom Premi O Material Enfilcon ASifilcon AAsmofilcon A Dk10082129 Dk/t125117161 Water content 46%32%40% Powers-0.25 to -6+20 to -20 BCR8.57.4 to 9.2 Replace2 weeks3 months2 weeks

11 Other Dk/t Values Soflens 38 = 21 AV2 = 20 Focus Monthly = 15 Focus Dailies = 27 SF 1 Day = 16 Proclear = 30

12 Pure Vision (B&L) Performa surfacing process Do not use abrasive cleaners, H 2 O 2, Miraflow Glassy islands Available in toric & multifocal DW/EW/CW

13 Focus Night & Day, Air Optix Aqua O2 Optix & O2 Optix Custom (Ciba) No restrictions on care solutions Plasma coating Surface chemically uniform Uniformly coated with hydrophilic polymer N&D DW/EW/CW, Air & O2Optix DW/EW, O2 Optix DW, Air Optix for Astigmatism

14 Acuvue Advance & Oasys (Vistakon) AV2 design, UV blocker No coating, Hydraclear wetting agent on surface and throughout lens AV Adv. DW, Oasys DW/EW Toric and Multifocal

15 Biofinity & Avaira (CooperVision) Company reports no surface treatment or wetting agents Aquaform comfort science DW at this time

16 Lens Surface Modifications Silicone elastomer materials generally display: –Decreased surface wettability –Increased lipid interaction –Accentuated lens binding Require “surface modification” 2006-01-0004

17 Surface Modifications O 2 OPTIXNIGHT & DAY PureVision ACUVUE AdvanceACUVUE OASYS Permanent, chemically bonded plasma treatment for a smooth, continuous surface Surface made up of silicate islands that do not completely cover the surface No permanent plasma treatment All photos 5 x 5 micron resolution 2006-01-0004

18 Surface Modifications Focus N&D, O2 Optix, Air Optix O2 Optix Custom PureVisionAV Advance, AV Oasys Biofinity, Avaira PremiO Ciba VisionBausch & Lomb VistakonCooperVisionMenicon Plasma coating Plasma oxidation Internal Wetting agent- polyvinyl pyrrolidone (PVP) NoneNanogloss

19 Biofinity Siloxane molecules attract and bond to surrounding water molecules, continuously wetting and lubricating the material (Courtesy CooperVision)

20 Modulus “Stiffness” Makes it easier to handle Masks astigmatism?

21 Increased Modulus Mucin Balls GPC/CLPC SEALs Edge Fluting

22 Modulus MaterialHydrogel/SiHyModulus (MPa) HEMAHydrogel0.50 AV AdvanceSiHy0.4-0.43 AvairaSiHy0.5 AV OasysSiHy0.6-0.72 BiofinitySiHy0.75-0.8 PremiOSiHy0.9 O2Optix/Air OptixSiHy1-1.2 PureVisionSiHy1.1-1.25 Focus N&DSiHy1.4-1.52

23 O2Optix Purevision Oasys Advance Modulus (MPa) Dk SiH Dk & MODULUS Night&Day An increased Dk is linked with an increase in modulus biofinity Courtesy CooperVision

24 Comfort? Silicone hydrogel lens materials are different from conventional HEMA-based materials Some patients will experience increased “awareness” when refit 2006-01-0004

25 Dailies with AquaRelease (Ciba) AV 1Day Moist (Vistakon)

26 Water content = weight of water in lens/ total lens weight X 100

27 Water Content Range of water content 24-79% HEMA by itself has 38% water Plays a role in determining: Dk/t, durability, stability, deposit formation, pore size

28 Silicone Hydrogels Hema – Hydrophilic Silicone – Hydrophobic Dk-Hema = 10 Dk-Silicone = 250

29 Dk compared with % Water

30 Dk/t and H 2 O Conventional LensesSilicone Hydrogels ACUVUE ® OASYS ™ PureVision ® NIGHT & DAY ® Frequency® 55. Biomedics ® Soflens ® 66 ACUVUE ® 2 O 2 OPTIX ™ ACUVUE ® Advance ™ 2006-01-0004

31 FDA Classification Group 1 – nonionic, low water Group 2 – nonionic, high water Group 3 – ionic, low water Group 4 – ionic, high water Group 5 - ???????

32 Groups 2 & 4 avoid Heat disinfection Sorbic acid/potassium sorbate Deposit-prone patient

33 Oxygen Permeability Increases with water content in HEMA lenses Increases as water content decreases in Silicone Hydrogels Oxygen transmission increases with decreases in CT Dk ranges 8.3 to >100 Tear exchange 1-2%

34 Oxygen Profiles (-3.00 sph.) 2006-01-0004

35 Examples Hydrocurve II 45%, Dk 12, CT.05, Dk/t 24 Hydrocurve II 55%, Dk 22, CT.05. Dk/t 44 Optima 38, Dk 8.5, CT.06, Dk/t 14 Optima FW, Dk 8.5, CT.035, Dk/t 24 B&L 70, Dk 33.8, CT.1, Dk/t 33.8

36 Wettability Aids in lid closure and comfort Contaminants adhere to surface Increase sensitivity to preservatives

37 Internal Wetting Agents Polyvinyl pyrrolidone (PVP) Polyvinyl alcohol (PVA)

38 Material Selection Patients with Ocular Compromise Refractive Error including astigmatism Deposit-prone patients Age Lens Handling Part-time Wearers Compliance Oxygen requirements Patient’s Interest Dry Eye

39 Soft Lenses for Dry Eye Proclear Extreme H2O AV Advance Preference CSI Dailies with Aquarelease AV 1 day Moist O2 Optix/Air Optix Aqua Focus N&D AV Oasys Purevision Biofinity Frequency ?

40 Why decreased dryness in SiHy? Low Dk of hydrogels leads to hypoxia –Decreased corneal sensitivity, decreased tear flow –Leads to inflammation and ocular surface damage –Leads to lacrimal damage

41 Lens Design Lathe-cut Cast molded Spun-cast Lathe-cut back & spun-cast front

42 Optics Aspheric lenses to optimize spherical clarity or correct spherical aberration Focus N&D, Air & O2 Optix, PureVision, Frequency Aspheric, Biofinity, Avaira

43 FITTING Patient Selection

44 Indications Spherical RE Low astigmats Lenticular astigmatism Career enhancing Occasional wear Inability to adapt to GP’s Responsibility Motivation Chronic GP complications

45 Low astigmats Spherical equivalent Soft Toric Aspheric design

46 Career Enhancing Athletes Actors Models Eye Changing Tints Fountain of Youth

47 Responsibility Age restrictions Participation in the costs of the lens

48 Essentially every other SCL patient entering your office desires the freedom and flexibility of sleeping in their lenses, at least occasionally. Don’t want to sleep in their lenses 54% Want to sleep overnight in their lenses occasionally 21% Variability in Lifestyle Source: CIBA Vision, data on file, 2005. 25% Want to sleep overnight in their lenses on a regular basis 2006-01-0004

49 Most who sleep in their lenses do so frequently – average is 21 nights/month 41% of those sleeping in their lenses do so for more than 7 nights continuously –Many (28%) are wearing lenses not approved for such use 84% of soft contact lens wearers accidentally fall asleep or nap with their lenses Sleeping in lenses (Source: CIBA Vision, data on file) 2006-01-0004

50 Contraindications Inflammation/Disease of Anterior Seg Systemic disease Pregnancy Poor hygiene Lack of motivation Irregular cornea RK Chronic allergies Chronic use antihistamines GPC Astig.>1D Work environment Poor tears

51 Systemic diseases Epilepsy Diabetes Mental incompetency

52 Pregnancy complications Dry eyes Refractive changes- Corneal thickness changes Decreased corneal sensitivity Increased tear viscosity

53 Preliminary evaluation is important for determining patient suitability

54 Case 1 35 y.o male banker Desires CL’s for occasional sports activities

55 Case 2 24 y.o female Wants CL’s 1 st time 3 months pregnant

56 Case 3 Auto mechanic Wants CL’s Poor hygiene

57 Lens Selection Lens Type DW, FW, EW, CW Replacement schedule Tints What is the patient interested in?

58 DW, FW, EW, CW Wear 12-14 hours a day Remove daily Occasional overnight wear Full time overnight wear 7 days/6 nights 30 day wear

59 Educate and Set Proper Expectations- Making the switch Oxygen Transmission Corneal Health Modulus Replacement schedule Discuss going from hydrogel EW to SiHy EW or CW Give the patient 1-2 weeks

60 CW Patient Education Use appropriate solutions for SiHy’s Rub the lenses to clean, except ClearCare Do not swim in lenses and do not sleep in lenses after swimming Clean & disinfect upon removal Need back-up glasses with updated Rx Examine every 6 mths. Bring glasses and solutions to visits Remove when ill and do not sleep in them Must be 100% healthy to wear CW Remove if dirty or FB sensation to clean & disinfect Replace with fresh, clean lenses each month Showering in lenses?

61 Even in a BMW, you need to slow down when it is icy. - Dr. Ghormley

62 CW Wearing Schedule New CL patient – Immediate CW Follow-up: 1wk, 3wk, 6wk, 6mth DW SCL patient – 3 days DW, CW Follow-up: 10 days, 3 wk, 6wk, 6mth EW SCL patient – 1 week DW, CW Follow-up: 2wk, 3wk, 6wk, 6mth

63 Replacement Schedule Daily Weekly Every 2 weeks Monthly Every 2 months Quarterly Traditional/Conventional

64 Tints Handling Enhancing Opaque Opaque wild & crazy

65 Lens Inversion Markings

66 BCR 4-5D flatter than flat K Steepest BCR = flat K >45D Middle BCR = flat K 41-45D Flat BCR = flat K < 41D

67 Lens Diameter HVID +2 = Lens Diameter 13.8-15mm

68 Lens Power Vertex > + 4D Spherical equivalent for < 1D cyl Residual astigmatism = Refractive cylinder

69 Center Thickness Greater minus – Thinner Greater plus – Thicker Thicker lenses are easier to handle Thinner lenses provide greater oxygen transmission

70 Fitting Evaluation Empirical vs. Diagnostic

71 Case 1 39.50/40.00 @90 OU OD –2.00D OS –1.75-0.50 X180

72 Case 2 OD 43.00 Sph. OS 42.50/43.50 @90 OD –4.50 OS –4.50-1.00X180

73 Fitting Insert lenses and let settle 10-15 minutes Assess position, coverage and movement Centration- centered Complete corneal coverage 0.5-1mm lag, Push-up test

74 Too tight Conjunctival drag Negative push-up test No movement

75 Too loose > 2mm lag Moving off cornea Decentered inferiorly Edge lift Slides inferior on superior gaze

76 Edge fluting www.siliconehydrogels.org

77 Determine visual acuity and lens power by best sphere & sphero-cylindrical over-refraction

78 Over-keratometry Flat Fit Mire distortion which becomes more distorted on blink Steep Fit Clear mire on blink which becomes distorted

79 Assess Patient Comfort Dispense out of Inventory/Trials? Parameters required to order (BCR, Rx, Material name, diameter?, CT?, tint) Verify lens specifications prior to dispensing

80 Follow-Up Evaluations

81 Patient Education Provide written instructions Don’t bombard them with info Give them nuggets Provide wearing schedule Teach I & R Provide Informed Consent Teach lens & case care Teach how to open blister pack

82 Nuggets Use a rewetting drop prior to removal Dial toric lenses prior to removal FB under lens, pull onto sclera and blink back on Use viscous solution like daily cleaner to unroll edges

83 Lens Insertion tips Fingers dry Make sure lens is not inverted Inspect lens Place on sclera or directly on cornea

84 Lens Removal tips Slide the lens off onto sclera Pinch off with the finger pads

85 Informed Consent should cover: Specifies patient taught I&R, care Emergency phone number Risks Dr. copy & patient copy

86 Progress Evaluations Case Hx VA Over-Ks SLE lenses on & off K’s with lenses off Refraction RTC schedule

87 Case History Problems/complaints WT Solutions: Are they compatible? Have they switched? Are they disinfecting, enzyming, cleaning? Are they compliant?

88 SLE with lenses Clear, white eye Position Coverage Movement Defects in the lens

89 SLE without lenses Edema (microcysts, striae, polymegethism) Neovascularization Limbal engorgement Injection Lid eversion Fluorescein Evaluation (Rinse out)

90 Case 1 A patient is fit in a Frequency 55 lens, base curve radius of 8.4mm, worn DW. It is a group 4 lens with a water content of 55%. It comes in base curve radii of 8.4, 8.7 & 9.0. RTC in 2 wks with trial lens. Upon the return visit, engorged limbal vessels and conjunctival drag. What do you plan to do?

91 Case 2 Focus Monthly wearer, DW basis Group 4, BCR 8.6 Using Complete, appears compliant but has deposits Name other options for this patient?

92 Case 3 Your patient works at a computer at work. She uses frequent rewetting drops. She experiences dryness. What might be helpful for her?

93 Case 4 Patient is wearing AV lenses 2-3 weeks continuously. Some signs of edema. What lens options might you want to discuss with the patient?

94 Case 5 Patient is interested in obtaining soft extended wear tinted bifocal toric lenses.

95 Case 6 Patient had ocular trauma to the left eye which resulted in a large distorted pupil. The patient is unhappy with the cosmetic appearance. The iris color of the OD is blue.

96 Case 7 Patient desires to wear soft lenses; however, he desires very little care regimen.

97 Case 8 Patient is being fit for CL’s for the 1 st time. She loves monovision; however, she has trouble seeing the lenses when handling. What would you do for her?

98 Case 9 Patient was fit in Focus Night & Day. They previously wore AV 2 for 1-2 weeks EW. They return for a 1 week check. They are complaining of lens awareness. SLE findings are normal.

99 Case 10 Patient is wearing PureVision lenses. At their 2 week follow-up visit you notice a mild coating on the lenses. The patient is using Aquify with their lenses. Any thoughts on what might be happening?


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