Introducing the envista IOL. Dr Kerrie Meades PersonalEYES Pty Ltd

Transcription

1 Introducing the envista IOL Dr Kerrie Meades PersonalEYES Pty Ltd

2 envista IOL Basic Features Hydrophobic acrylic IOL, single piece 6.0mm aspheric neutral optic, modified C haptic 12.5mm overall length 0 to 34.0 diopters (0 10D, 30 34D in 1.0D; in 0.5D) Fenestrated haptics design to evenly transmit forces 360 o posterior square edge UV block

3 envista IOL Basic Features 2.2 mm wound assisted 6.0 mm

4 Hydrophobic vs Hydrophilic

5 Hydrophobic IOLs Advantages Higher refractive index Excellent optical clarity Excellent biocompatibility Better PCO prevention Excellent for surface engineering (toric, diffractive etc) Disadvantages Must be purpose made High tech molecules More expensive

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10 Hydrophobic vs Hydrophilic Acrylic Hydrophilic more flexible lower reflective index PCO rate? higher glistening? Hydrophobic more rigid higher reflective index PCO rate? lower glistening more likely

11 envista Polymer Novel HEMA styrene copolymer, cross linked polymer, UV blocker 4% water content Refractive index of 1.54 (AcrySof: 1.55, Tecnis: 1.47, Rayner HEMA: 1.46) Glass transition temperature of 30 C

12 Features of the envista IOL High refractive index thin optic Hard surface difficult to scratch Controlled unfolding 360 square edge favourable for prevention of PCO No glistenings

13 Nanoindentation Measurement of surface hardness

14 Nanoindentation Measurement of surface hardness MPa Acrysof envista Sensar Hoya 1 Mentak K et al, ESCRS 2007

15 envista IOL Very hard, scratch resistant surface High tensile strength

16 envista IOL

17 What is glistening? Small fluid filled pockets ( vacuoles / cavitations ) form within the superficial layer of the acrylic IOL Fluid, in the form of vapour, condenses then lines the wall of vacuoles Observed in all types of IOL, primarily in hydrophobic acrylic lenses First clinicopathologic study reported by Nichamin/Apple in ASCRS 1994.

18 Grade 3+ glistenings Images courtesy of Dr D Chan, Singapore

19 Case 1 = 20/30 but miserable and explanted Images courtesy of Dr D Chan, Singapore

20 case 2 case 3 case 4 case 5 case 6 20/20 but miserable Courtesy of Prof D Apple, AAO 2008

21 Is glistening common? Published studies on glistening formation rates of a very common hydrophobic acrylic one piece IOL Study 1: Nearly 60% between 4 and 22 months postoperatively 1 Study 2: 29.5% (38 cases from 129 eyes) 2 Study 3: 60.4% (157 cases from 260 eyes) 3 FDA Web site, search for intraocular lens glistenings Up to June 2009 : 106 records To date : 223 records 1. Trattler. Identifying the best acrylic IOL materials and assessing the visual significance of glistenings 2. Moreno Montanes et al. J Cataract Refract Surg Colin et al. J Cataract Refract Surg

22 Grading of Glistening Grade Scattering area (% of 2x2mm2) Number Typical sizes Description 1 < 0.5% μ Mild 2 < 2% μ Moderate 3 <10% μ High 4 > 10% > μ Severe

23 Images courtesy of Dr R Olson

24 What causes glistening? Manufacturing causes Non uniformity of material 1 Material composition 2 Manufacturing technique 2 Sterilization1 Temperature change Packaging 2 Pre implantation causes Warming 1 Handling 1 1 Shiba et al. Eur J Ophthalmol Dhaliwal et al. J Cataract Refract Surg Colin. J Cataract Refract Surg Wester. J Cataract Refract Surg

25 What causes glistening? Post implantation causes Temperature changes Water vacuoles due to hydrates of IOL 2 IOL power 3 Glaucoma 3 Other conditions leading to breakdown of postoperative visual function and/or the blood aqueous barrier 4 1 Shiba et al. Eur J Ophthalmol Dhaliwal et al. J Cataract Refract Surg Colin. J Cataract Refract Surg Wester. J Cataract Refract Surg

26 Pre hydration How to avoid glistening Traditional hydrophobic IOL : 0.3% 0.5% H 2 O evvista IOL : 4% H 2 O (at equilibrium with NaCL) Packaging 0.9% NaCl solution at equilibrium, no water movement in and out of IOL In aqueous humor: 0.9% salinity again, no water movement in and out of IOL

27 envista US Pivotal Study 1 IOL glistenings were evaluated via the traditional method of retroillumination slit lamp examination utilizing a photographic grading scale provided in the protocol. The grading scale consisted of (in order of severity), none, grade 0 (trace), grade 1, 2, 3, or 4 No glistenings were reported at any time point Visit 3 (4 Months) Grading Scale N % N % Trace Mild Moderate Severe Very severe None Total graded Visit 4 (6 Months) 1 Data on file, Bausch and Lomb. Final Clinical Study Report: A prospective multicenter clinical study to evaluate the safety and effectiveness of a Bausch + Lomb one piece hydrophobic acrylic intraocular lens in subjects undergoing cataract extraction.

28 Posterior Capsular Opacification Designed to Minimise PCO Modified C haptics posterior vault, tight opticcapsule contact 360 o square posterior edge inhibits LEC migration

29 Hydrophobic, capsule friendly The mean EPCO score at Form 4 (6 months) was (SD = 0.101) 1 EPCO Capsulorhexis Score a Form 4 (Days ) Mean (SD) (0.101) Min, Max (0.000, 0.726) 95% CI (0.013, 0.050) Distribution of Scores (n, [%]) Within (98.3) Within (100.0) N b 118 N missing c 3 Total d Data on file, Bausch and Lomb. Final Clinical Study Report: A prospective multicenter clinical study to evaluate the safety and effectiveness of a Bausch + Lomb one piece hydrophobic acrylic intraocular lens in subjects undergoing cataract extraction.

30 envista IOL Summary Hydrophobic acrylic IOL presents in saline Glistenings: no reports at any time Aspheric UV block optics, 2.2mm incision Safety and effectiveness: superior to FDA grid of historical controls

31 Thank you