Transcript TEK - CLEAR - NewTech s.p.a.

TEK-CLEAR ACCOMMODATIVE IOL
Dr. Mark Wevill, Ultralase, UK
Presbyopia International Barcelona 2009
No financial disclosures
FEATURES
Single piece accommodative hydrophilic acrylic IOL (26%
water content)
5.5 mm optic, 10.0 to 11.0 mm haptic diameter
Square-edge optic and haptic
2.8 mm incision size
+17.0D to +30.0D (0.5D steps)
MECHANISM
OF ACTION
EFFICACY: ANATOMIC FACTORS
Diameter of the capsular bag:
•
•
•
Larger capsules (myopes) allow greater forward
displacement. (Heatley, Marshall, 2004)
Capsule shrinks with surgery.
Calculated diameter based on axial length &
keratometry. (Tehrani 2003)
EFFICACY: ANATOMIC FACTORS
Thickness & elasticity of capsule:
•
•
Thicker & less elastic reduces
movement.
Capsule thinner posteriorly &
thicker at equator. Age (>35)
doesn’t affect elasticity.
(Krag & Andreassen, 2003)
EFFICACY: ANATOMIC FACTORS
Vitreous pressure exerted on the capsule:
2-10 cm H20 (average 4 cm H20 ).
EFFICACY: BIOMETRIC FACTORS
Missotten 2004 Accommodative amplitude (AA)
decreases with longer axial length and higher
average keratometry (Km). e.g. Km 43D
AL 20mm, 1mm IOL ant shift = AA 2.4D
AL 28mm, 1mm IOL ant shift = AA 0.37D
Nawa 2003 Per mm anterior displacement:
AA 0.8D for 11D IOL and 2.3D for 30D IOL
EFFICACY: BIOMETRIC FACTORS
Haptic length: Greater haptic length increases
potential displacement of optic.
Increased haptic length requires smaller optic
diameter.
Crystalens AT-45
4.5mm optic
10.5 mm haptic
HAPTIC: 3mm
Akkommodative
1CU
5.5mm optic
9.8 mm haptic
HAPTIC: 2.15
mm
EFFICACY: BIOMETRIC FACTORS
TEK-CLEAR:
5.5 mm optic
10 / 11 mm haptic
HAPTIC: 2.25 /
2.75mm
EFFICACY: PCO
Anterior & posterior opacification limits IOL
accommodation. (Mastropasqua, 2007)
EFFICACY: PCO & Tek-clear
Square IOL optic edge induces contact inhibition to
migrating LEC’s & reduces PCO. (Nishi 1998)
SURGICAL ISSUES
- Select IOL power:
<24.5mm HofferQ, >24.5mm SRK/T
- Select IOL size: Tehrani formula
CBD = (0.277-(0.00973xAL2) + (0.58xAL) + (0.04313xD)
-
3mm incision
Astigmatism control
6mm capsulorhexis
In the bag fixation
POST OP FOLLOW UP
- Cycloplegic 3-5 days
- Delay YAG until at least 3/12
- Yag <4.0mm
STUDY:
Studený P et al, May 2009
Number of patients: 18 (32 eyes)
Average age of patients: 60.6 (28-81)
Follow up time: minimum 3 months
Preoperative UCVA: 0.28 (0.05- 0.7)
Preoperative BCVA: 0.65 (0.05-1.0)
Examination objectives: UCVA, BCVA, accommodative
amplitude
POSTOP ACCOMMODATION
ASSESSMENT
Push-up test (Subjective)
Defocus (Subjective)
Plusoptix (Objective)
Subjective measures of accommodation
AFFECTED BY:
 Push up / down
 Pupil
 Light
 Training & memory
 End point 6/12, N8 …

RAF rule
Subjective measures of accommodation
AFFECTED BY:
 Push up / down
 Pupil
 Light
 Training & memory
 End point 6/12, N8 …


RAF rule
Defocus curves
Objective measures of accommodation
Ideal instrument



Truly objective
Validated: subjective results
eyes being examined
Tolerant to eye & head movements
Accommodative stimulation
Natural target / pharmacologically induced
Instruments
Purkinje images
Photorefractors
Aberrometry
Scheiner’s principle
Fundus light intensity
Image size
Ant chamber depth
- Scheimflug
- IOL Master
PLUSOPTIX




Objective
Binocular auto-refractometer is placed 1 meter in front
of the patient
Fixation target is moved towards the patient
Changes in eye refraction are recorded – refraction
difference between short and long distance
Subjective vs Objective
accommodation measurements


OBJECTIVE: Measure dioptric change in the
power of the eye.
SUBJECTIVE: Measure a combination of:
- Effects of aberrations
- Blur perception
- Depth of field
- Dioptric change
Subjective tests overestimate accommodative response by
2.00 to 3.00D. Win-Hall & Glasser, JCRS Feb 09
RESULTS:
Dioptres of accommodation
PUSH UP
7 DAYS
3.9
(1-5)
1 MONTH 3.5
(1-5)
3 MONTH 4.2
(1-5)
RESULTS:
Dioptres of accommodation
PUSH UP
DEFOCUS
3.9
(1-5)
0.8
(0.5-1.25)
1 MONTH 3.5
(1-5)
0.9
(0.5-1.25)
3 MONTH 4.2
(1-5)
0.9
(0.5-1.5)
7 DAYS
RESULTS:
Dioptres of accommodation
PUSH UP
DEFOCUS
PLUSOPTIX
3.9
(1-5)
0.8
(0.5-1.25)
1.9
(0.9-3.0)
1 MONTH 3.5
(1-5)
0.9
(0.5-1.25)
2.2
(0.9-4.2)
3 MONTH 4.2
(1-5)
0.9
(0.5-1.5)
2.2
(1.0-3.6)
7 DAYS
CONCLUSION
The Tek-Clear IOL:
- Effectively produces pseudo-accommodation
- Customised size and powers according to patient
specifications
- Square edge technology to minimise PCO
- Large scale, longer term study published in the
peer review literature needed & is pending
Thank you
Tek-Clear Accommodative IOL is
manufactured by:
TEKIA, INC.
www.tekia.com
With thanks to:
Studený P. , Dědková B., Farkaš A., Vokrojová M., Siveková D., Břešťák M.
Oční klinika FNKV a 3 LF UK Praha
Oční oddělení , Karlovarská krajská nemocnice a.s.
Centrum Fetální medicíny Praha