Purpose: To develop a model of post-surgical corneas and its application to analyze the outcomes of standard and custom myopic LASIK treatments. Methods: The optical zone (OZ), transition zone (TZ) and periphery are segmented automatically by a clustering algorithm. For each point, we compute three physical magnitudes: Gauss curvature, root-mean-square (RMS) fit error, and distance to the vertex, which are then used as local descriptors in the segmentation. Both pre-surgical and post-LASIK

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... al topographies were compared using monozone and multizone models. Three groups of patients (31 eyes) were studied according to the treatments applied: Allegretto (custom), Zyoptix (custom) and PlanoScan (standard). Results: The multizone model improved the goodness of fit from 2.4 ± 0.7 to 1.2 ± 0.4 μm (post-LASIK). The segmentation permitted us to estimate the diameter, shape and decentration of the different zones. The estimated central ablation (OZ) area was always lower than nominal value (average diameter 6.6 ± 0.3 mm versus 5.5 ± 0.4 mm) and showed elliptical shape (average e = 0.27). In the OZ, curvature radii increased after surgery, and conic constants (-0.41) became positive (+0.29). No significant differences were found between Zyoptix and PlanoScan: Corneal HOA increased by a factor of 2; for Allegretto HOA increased by 3. Conclusions: The analysis of the three different LASIK treatments showed no improvement of custom over standard treatments. The mutizone model shows a higher fidelity representation of the corneal topography and permits a deeper understanding of the post-surgical cornea. Purpose: To evaluate the changes in total and corneal aberrations and the compensation of aberrations within the human eye after conventional myopic laser in situ keratomileusis (LASIK). Methods: Total and corneal aberrations were measured preoperatively and 3 months postoperatively for 57 eyes. The NIDEK EC-5000 excimer laser was used for all treatments. Total and corneal aberrations root-mean-square (RMS) values were calculated out to the 6 th Zernike orders for a 6.0-mm pupil diameter. The percentage of increase after surgery was defined by the ratio between the RMS values preand postoperatively for each of the corneal and total eye aberration groups. The compensation between corneal and internal aberrations for a given aberration group was defined by the ratio:(corneal aberration group RMS-total eye aberration group RMS)/ corneal aberration group RMS). A p-value less than 0.05 was considered statistically significant. Results: Postoperatively, higher order aberrations showed a statistically significant increase after myopic LASIK by a factor of 1.77±1.26 (total) and 2.47±2.25 (corneal) (p <0.05). Coma aberration increased by 2.43±2.61 (total) and 2.56±2.66 (corneal) . Spherical aberration increased by a factor 1.46±1.83 (total) and 2.64±2.24 (cornea). The values of the ratio of compensation did not show statistically significant differences before and after LASIK for individual aberrations (p>0.05). Conclusions: Although myopic LASIK induced significant corneal aberrations, the level of partial compensation of corneal aberrations by internal structures remained unchanged. These results may suggest that a previously described emmetropization that is effective not only with developmental factors but also with acquired variations in corneal shape. Purpose:To verify whether there is any difference in visual outcome after performing WASCA (wavefront supported corneal ablation) and iris recognition guided WASCA (IR-WASCA) of the same patient 3 month after surgery. Methods: This was a prospective randomized study of 104 myopic eyes (52 patients) that had LASIK using the MEL80 excimer laser system. IR-WASCA was used in the first eye of the patient (study group) and the other eye of the same patient was operated with WASCA surgery (control group). Mean refractive error was similar between left and right eyes of the same patient. Higher order aberration(HOAs), Contrast sensitivity function(CSF), UCVA and BCVA were recorded preoperative and 1-month, 3-month postoperative. Corneal topographic maps were performed preoperative and 3-month postoperative. Results: The mean cyclorotation of IR-WASCA group was -2.0+/-4.2 degree(rang -11.2~7.9 degree). At 3 month after surgery, UCVA was 20/20 or better in 96.2% of IR-WASCA group and 90.3% of WASCA group. A significant difference in CSF was found between the two groups at 2.5, 1.6, 1.0 degree. Conclusions:IR-WASCA provides a better quality of vision as they detect and compensate cyclorotation to give a more precise ablation profile. Purpose: To evaluate and compare the relative impact on the vision quality caused by LASIK surgery, in patients with different optical quality at the pre-surgical stage. Methods: In this study we evaluate the changes in the eye's optical quality after LASIK surgery, taking into account the results reported for several groups of patients with different optical qualities at the pre-surgical stage. We analyze relative the improvement or worsening in the visual quality that take place in those different groups considered.The eye's optical quality is measured by means of the double-pass system OQAS (Optical Quality Analysis System, Visiometrics), which provides the OQAS VALUE (OV), parameter that accounts for the visual quality of the patients. Specifically, its standard values range from 0 to 2 approximately. Values higher than 1 are related to an acceptable visual quality.25 LASIK myopic patients were included in this study. Their eye's optical quality was analyzed by means of the OQAS VALUE and the Visual Acuity (BSCVA, best spectacle corrected visual acuity, and UCVA, uncorrected visual acuity), at the pre-surgical stage and one month after the intervention. Only patients with a preoperative BSCVA of 20/25 or better were included in the comparison. The following groups of patients' eyes with different optical quality ranges (presurgical) were considered: 5 eyes corresponding to patients with OV<0.6, 11 with 0.6 or = 20/16 and 94.3% > or = 20/20, and in the WFG-PRK group, 54% and 94.3%, respectively. The mean pretreatment total high-order aberrations (total HOA) was 0.334+/-0.07μm in the WFG-LASIK group and 0.359+/-0.11μm in the WFG-PRK group (P= .594). At six months, the mean total HOA was +0.455+/-0.13D and -0.441+/-0.15D, respectively (P= .688). Contrast sensitivity has improved similarly for both groups. Conclusions: RMS values of total HOA and other terms showed no statistically significant difference between custom LASIK and custom PRK. Contrast sensitivity has improved after wavefront-guided ablations without significant difference between LASIK and PRK. Both techniques were effective in correcting low myopia and myopic astigmatism with good high and low contrast visual acuity. Purpose: To evaluate stereoscopic vision after LASIK and the role of post-surgical interocular differences in higher-order eye aberrations, corneal asphericity, and initial anisometropia. Methods: We measured maximum disparity with a mirror stereoscope pre-(bestcorrected) and after LASIK for 30 patients. Their mean pre-operative spherical refractive error was -4.7±2.0 D, ranging from -1.0 to -8.0 D. Data on aberrometry were taken with a WASCA aberrometer. Corneal shape data were provided by a corneal topographer. For each patient, the anisometropia was computed as the difference between the spherical equivalent of each eye. Results: The results showed that stereoscopic vision is less effective after LASIK, since for 93% of the patients, maximum disparity diminished. This lower maximum disparity implies a reduction in the physical region where stereoscopic perception occurs and thus in the quality of stereopsis. We also found that the larger the interoculardifferences in post-surgical corneal asphericity the less effective the stereopsis (r=0.82, p<0.01); on the other hand, the greater the differences in the higher-order aberrations, the worse the quality of stereoscopic vision (r=0.85, p<0.01). Analyzing pre-LASIK anisometropia we found that maximum disparity diminishes for increasing values of initial anisometropia (r=0.87, p<0.01). Conclusions: Our results indicate that stereopsis deteriorates after LASIK. Ablation algorithms should minimize interocular-differences (aberrations and corneal aasphericity) to avoid a decrease in binocular visual performance. Purpose: Our study describes the results of a Phase III United States FDA investigation on the Artisan phakic intraocular lens (PIOL) for the correction of hyperopia up to +12.0 D. The endpoints focused on refraction efficacy, predictability, stability, and safety. Methods: The Artisan hyperopic PIOL is fabricated from ultraviolet-absorbing polymethylmethacrylate. It was implanted in 95 eyes of 60 subjects at 13 participating trial sites located throughout the United States. Inclusion criteria included endothelial cell counts (ECC) of at least 2000 cells/mm 2 and anterior chamber depth (ACD) of at least 3.2 mm. The goal of all surgeries was emmetropia. 46 eyes were followed for 3 years. Results: Implant diopter strength averaged 7.55 ± 2.04 D (range +4.0 to +12.0 D). Preoperative ACD averaged 3.40 ± 0.17 mm. The pre-operative mean spherical equivalent (MSE) averaged +5.47 ± 1.45 D, while the third post-operative year MSE averaged -0.56 ± 0.65 D. By this third post-operative year, 65.5% of eyes were within ± 0.5 D and 98.2% were within ± 1.0 D of the intended correction. Pre-operative best corrected visual acuity (BCVA) Purpose: To determine the changes in higher-order aberrations (HOA) following cataract surgery. Methods: The cohort comprised 39 eyes from 39 patients (mean age 73.1, SD 7.7) who had undergone cataract extraction by phacoemulsification and intra-ocular lens implantation. Eight HOAs (Total, TiltS1, High, TComa, TTrefoil, T4foil, TSph and HiAstg) were measured using the NIDEK Optical Path Difference Scanning System ARK-10000 aberrometer prior to surgery (Mean 3.5 weeks, SD 2.0), approximately 10 weeks post operatively (Mean 10.7 weeks, SD 7.6) (PO1) and approximately 18 months post-operatively (Mean 18.6 months, SD 3.5) (PO2). The root mean square (RMS) values for each HOA were separately compared over the three time periods. Results: Following cataract extraction and IOL implantation, the group mean RMS values for most HOAs progressively decreased in magnitude at PO1 and at PO2. However, the reductions in magnitude only reached statistical significance at PO1 for Total (p<0.001), Tilt (p=0.002), and High (p=0.039) and additionally at PO2 for T3foil (p=0.007), and TSph (p=0.004). The differences in magnitude between PO1 and PO2 did not reach statistical significance. Conclusions: As would be expected, cataract extraction and IOL implantation resulted in an improvement in most aberrations at PO1 and this improvement was maintained at PO2. However, Tcoma and Hi-Astig remained unchanged and would therefore appear to be largely independent of the crystalline lens. This latter finding has implications for the design of future IOLs.