Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Matt Sheehan - PhD progress presentation
Document related concepts
no text concepts found
Transcript
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)
