Introducing the enVista IOL - PersonalEYES · enVista IOL Basic Features Hydrophobic acrylic IOL,...
Transcript of Introducing the enVista IOL - PersonalEYES · enVista IOL Basic Features Hydrophobic acrylic IOL,...
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; 10‐30 in 0.5D)
Fenestrated haptics design to evenly transmit forces
360o posterior square edge
UV block
Hydrophobic IOLs
AdvantagesHigher refractive indexExcellent optical clarityExcellent biocompatibilityBetter PCO preventionExcellent for surface engineering (toric, diffractive etc)
DisadvantagesMust be purpose madeHigh tech moleculesMore expensive
Hydrophobic vs Hydrophilic Acrylic
Hydrophilic Hydrophobic
more flexible more rigid
lower reflective index higher reflective index
PCO rate ? higher PCO rate ? lower
glistening ? glistening more likely
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
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
0
2
4
6
8
10
12
MPa
Acrysof enVista Sensar Hoya
Nanoindentation ‐Measurement of surface hardness1
1 Mentak K et al, ESCRS 2007
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.
What is glistening?
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 postoperatively1
❖ 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 http://www.eyeworld.org/ewsupplementarticle.php?id=261.
2. Moreno‐Montanes et al. J Cataract Refract Surg. 2003.
3. Colin et al. J Cataract Refract Surg. 2009.
Grading of Glistening
GradeScattering area (% of 2x2mm2)
NumberTypical sizes
Description
1 < 0.5% 0 ‐ 50 20μ Mild
2 < 2% 51 ‐ 250 20μ Moderate
3 <10% 251 ‐ 2500 20μ High
4 > 10% > 2500 10μ Severe
What causes glistening?Manufacturing causes
❖ Non‐uniformity of material 1
❖ Material composition2
❖ Manufacturing technique2
❖ Sterilization1❖ Temperature change ❖ Packaging2
Pre‐implantation causes❖ Warming1
❖ Handling1
1 Shiba et al. Eur J Ophthalmol. 2003. 2Dhaliwal et al. J Cataract Refract Surg. 1996. 3 Colin. J Cataract Refract Surg. 2009. 4Wester. J Cataract Refract Surg. 2010.
What causes glistening?
Post‐implantation causes❖ Temperature changes
❖ Water vacuoles due to hydrates of IOL2
❖ IOL power3
❖ Glaucoma3
❖ Other conditions leading to breakdown of postoperative visual function and/or the blood‐aqueous barrier4
1Shiba et al. Eur J Ophthalmol. 2003. 2Dhaliwal et al. J Cataract Refract Surg. 1996. 3Colin. J Cataract Refract Surg. 2009. 4Wester. J Cataract Refract Surg. 2010.
How to avoid glistening
Pre‐hydration❖Traditional hydrophobic IOL : 0.3% ‐ 0.5% H2O
❖evVista IOL : 4% H2O (at equilibrium with NaCL)
Packaging
❖ 0.9% NaCl solutionat equilibrium, no water movement in and out of IOL
❖ In aqueous humor: 0.9% salinityagain, no water movement in and out of IOL
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
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.
Grading Scale N % N %
Trace 0 0.0 0 0.0
Mild 0 0.0 0 0.0
Moderate 0 0.0 0 0.0
Severe 0 0.0 0 0.0
Very severe 0 0.0 0 0.0
None 122 100 118 100
Total graded 122 118
Visit 3 (4 Months)
Visit 4 (6 Months)
enVista US Pivotal Study1
Posterior Capsular OpacificationDesigned to Minimise PCO
Modified‐C hapticsposterior vault, tight optic‐capsule contact
360o square posterior edge
inhibits LEC migration
Hydrophobic, capsule‐friendly
EPCO Capsulorhexis Scorea Form 4 (Days 120-180)Mean (SD) 0.032 (0.101)
Min, Max (0.000, 0.726)
95% CI (0.013, 0.050)
Distribution of Scores (n, [%])
Within 0.5 116 (98.3)
Within 1.0 118 (100.0)
Nb 118
N missingc 3
Totald 121
•The mean EPCO score at Form 4 (6 months) was 0.032 (SD = 0.101)1
1Data 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.
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