Laser correction of refractive disorders and intraocular lens reshaping

Session Details

Session Title: Refractive
Session Date/Time: Sunday 22/02/2015 | 08:30-11:00
Paper Time: 10:03
Venue: Sadirvan A
Co Author(s): :                  

Abstract Details


Human prosthetic lens replacements are the most efficient technique to restore vision after cataract surgery or in cases of high levels myopia or hyperopia. Correction of high myopic refractive errors with excimer laser corneal surgery requires extensive ablation of corneal tissue, with resultant less predictable refractive outcomes.Our goal is to study the possibility of applying “refractive surgery” on artificial lens and is based on the idea of using laser ablation to modify the surface of intraocular lenses, as it seems very intriguing to apply laser radiation for the creation of micron-sized apodized patterns in soft polymers, instead of corneas.


Ablation experiments have already done on PMMA and acrylic IOL’s with 355 nm,λ=266 nm and λ=213 nm,pulse duration 6 ns. Nd:YAG laser with 35ps pulses, Er:YAG laser λ=2.94 μm, tp=180 ns and femtosecond lasers at λ = 800 nm and λ = 400 nm have been also used.


An overview of experimental efforts on IOLs laser reshaping is discussed. The ablation rates have to be measured and correlated with mathematical models for the optimum dosimetry of the ablation procedure. The laser beam uniformity has been checked before each procedure with a 3-D beam analyzer. It may also be checked during the procedure to ensure optimum results.


The ablation rate versus laser energy fluence of PMMA and acrylic IOL presents a logarithmic behavior in both cases. Crater walls present varied micro structure (e.g folds, holes) and the crater morphology reflect the profile of the laser beam. In some samples, the limits between irradiated and no irradiated surface appears elevated with debris deposited around the crater edges.


Quantitative and qualitative results of laser ablated intraocular lenses varied for each IOL type and laser wavelength, due to their different physical properties and UV absorption characteristics. It seems that for both types of intraocular lenses tends to saturate for the same laser fluence. The crater morphology reflects the laser beam profile, very important for IOL surface modulation.

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