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) Larger capsules (myopes) allow greater forward displacement. (Heatley, Marshall, 2004) Capsule shrinks with surgery. Capsule shrinks with surgery. Calculated diameter based on axial length & keratometry. (Tehrani 2003) Calculated diameter based on axial length & keratometry. (Tehrani 2003)

EFFICACY: ANATOMIC FACTORS Thickness & elasticity of capsule: Thicker & less elastic reduces movement. Thicker & less elastic reduces movement. Capsule thinner posteriorly & thicker at equator. Age (>35) doesn’t affect elasticity. (Krag & Andreassen, 2003) 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 H 2 0 (average 4 cm H 2 0 ).

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 mm 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 SRK/T 24.5mm SRK/T - Select IOL size: Tehrani formula CBD = (0.277-( xAL 2 ) + (0.58xAL) + ( xD) - 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 ( ) Preoperative BCVA: 0.65 ( ) 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 Push up / down Pupil Pupil Light Light Training & memory Training & memory End point 6/12, N8 … End point 6/12, N8 … RAF rule RAF rule

Subjective measures of accommodation AFFECTED BY: Push up / down Push up / down Pupil Pupil Light Light Training & memory Training & memory End point 6/12, N8 … End point 6/12, N8 … RAF rule RAF rule Defocus curves Defocus curves

Objective measures of accommodation Ideal instrument Truly objective Truly objective Validated:subjective results Validated:subjective results eyes being examined Tolerant to eye & head movements Tolerant to eye & head movements Accommodative stimulation Natural target / pharmacologically induced Instruments Purkinje imagesScheiner’s principleAnt chamber depth PhotorefractorsFundus light intensity- Scheimflug AberrometryImage size- IOL Master

PLUSOPTIX Objective Objective Binocular auto-refractometer is placed 1 meter in front of the patient Binocular auto-refractometer is placed 1 meter in front of the patient Fixation target is moved towards the patient Fixation target is moved towards the patient Changes in eye refraction are recorded – refraction difference between short and long distance 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. OBJECTIVE: Measure dioptric change in the power of the eye. SUBJECTIVE: Measure a combination of: 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 DAYS3.9 (1-5) 1 MONTH3.5 (1-5) 3 MONTH4.2 (1-5)

RESULTS: Dioptres of accommodation PUSH UPDEFOCUS 7 DAYS3.9 (1-5) 0.8 ( ) 1 MONTH3.5 (1-5) 0.9 ( ) 3 MONTH4.2 (1-5) 0.9 ( )

RESULTS: Dioptres of accommodation PUSH UPDEFOCUSPLUSOPTIX 7 DAYS3.9 (1-5) 0.8 ( ) 1.9 ( ) 1 MONTH3.5 (1-5) 0.9 ( ) 2.2 ( ) 3 MONTH4.2 (1-5) 0.9 ( ) 2.2 ( )

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 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 Tek-Clear Accommodative IOL is manufactured by: TEKIA, INC.