1. Personalised eye modelling for customised intraocular lens designs Matthew Sheehan, Eamonn O’Donoghue, Conor Sheil and Alexander Goncharov Photonics Ireland, Dublin, Ireland, September 7 th - 9 th 2011

2. History Ridley’s first intraocular lens – 1949 Kelman’s first phacoemulsification procedure - 1967 First FDA approval for an intraocular lens - 1981 Refractive surgery increases in popularity – 1990s Geometrical optics equations - 1973 Linear regression equations - 1980 Modern formula - 1980s to 1990s Intraocular lens power calculations

3. What lens power should we use ?

4. Refractive surgery popularity increases

5. Experiment Protocol – measurements performed pre and post cataract surgery Wavefront aberration of the eye (ZyWave) Refractive error and corneal curvature (Nidek ARK) Segmented axial length (Lenstar) Corneal topography (Atlas) Interferometry on the specific intraocular lenses (FISBA) Aims Investigate corneal shape changes due to the surgical incision Find parameters for predicting the implant resting position/depth Perform surface metrology for a specific implant design Final Goal Aquire knowledge to perform personalised eye modelling for customised intraocular lens designs

6. Biometry data summary 165 patients enrolled (64 males, 101 females) 33 excluded eyes 303 included suitable eyes (pre-surgery) age range: 32 to 98 years (mean 74 years) 88 eyes with usable post-surgery review data 74 eyes with usable single-echo implant data 14 eyes with usable double-echo implant data review period: 10 to 122 days (mean 31 days)

7. Lens implantation depth Cornea ~ 500 microns Cataractous Lens ~ 4 mm Retina ~ 200 microns Intraocular lens ~ 900 microns Vitreous ~ 16 mm

8. Predicting lens implantation depth

10. Surgery-induced corneal topography changes

11. Personalised eye modeling

12. Conclusions Early days for personalised eye modelling and customised intraocular lens designs Modern biometry instruments allow accurate measurement of two key parameters - optical segmented axial length - posterior corneal topography This methodology may be beneficial for typical cataract surgery patients as well as those with extreme ocular parameters (previous refractive surgery patients, high hyperopia)