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Personalised eye modelling for customised intraocular lens designs Matthew Sheehan, Eamonn O’Donoghue, Conor Sheil and Alexander Goncharov Photonics Ireland, Dublin, Ireland, September 7th- 9th 2011 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 Intraocular lens power calculations • Geometrical optics equations - 1973 • Linear regression equations - 1980 • Modern formula - 1980s to 1990s What lens power should we use ? n aq n vit P l c (n aq /K) c P A 2.5l 0.9K Refractive surgery popularity increases Experiment 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 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) Final Goal • Aquire knowledge to perform personalised eye modelling for customised intraocular lens designs 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) Lens implantation depth Cornea ~ 500 microns Retina ~ 200 microns Cataractous Lens ~ 4 mm Vitreous ~ 16 mm Intraocular lens ~ 900 microns Predicting lens implantation depth Surgery-induced corneal topography changes Personalised eye modeling 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)