Kata Miháltz

Femtosecond Laser Capsulotomy and Manual Continuous Curvilinear Capsulorrhexis Parameters and Their Effects on Intraocular Lens Centration

PURPOSE To measure and compare sizing and positioning parameters of femtosecond laser capsulotomy with manual continuous curvilinear capsulorrhexis (CCC). METHODS Femtosecond capsulotomies (Alcon-LenSx Lasers Inc) and CCC were carried out in 20 eyes of 20 patients, respectively. Intraocular lens (IOL) decentration, circularity, vertical and horizontal diameters of capsulotomies, and capsule overlap were measured with Adobe Photoshop (Adobe Systems Inc) 1 week, 1 month, and 1 year after surgery. Between-group differences of parameters and predictors of IOL decentration were determined with repeated measures analysis of variance, chi-square test, and logistic regression analyses. RESULTS Vertical diameter of CCC was statistically significantly higher in the first week and month. Significantly higher values of capsule overlap over 1 year and circularity in the first week showed more regular femtosecond capsulotomies. Horizontal IOL decentration was statistically significantly higher in the CCC group over 1 year. A significant difference was noted between the two groups in dichotomized horizontal decentration values at 0.4 mm with chi-square test after 1 week and 1 year (P=.035 and P=.016, respectively). In univariable general estimating equation models, type of capsulorrhexis (P<.01) and capsule overlap (P=.002) were significant predictors of horizontal decentration. Vertical diameter showed significant correlation to the overlap in the CCC group (1 week: r=-0.91; 1 month: r=-0.76, P<.01; 1 year: r=-0.62, P<.01), whereas no significant correlation was noted in the femtosecond group (P>.05). CONCLUSIONS More precise capsulotomy sizing and centering can be achieved with femtosecond laser. Properly sized, shaped, and centered femtosecond laser capsulotomies resulted in better overlap parameters that help maintain proper positioning of the IOL.

Comparison of Intraocular Lens Decentration Parameters After Femtosecond and Manual Capsulotomies

PURPOSE To evaluate a laser technique and manual technique to perform capsulorrhexis in cataract eyes. METHODS Anterior capsulotomy was performed with an intraocular femtosecond laser (LenSx Lasers Inc) in 54 eyes (FS group) and manual continuous curvilinear capsulorrhexis was performed in 57 eyes (CCC group). Circularity and area of capsulotomy and IOL decentration were measured using Photoshop CS4 Extended (Adobe Systems Inc) 1 week after surgery. Average keratometry, axial length, and preoperative anterior chamber depth were examined with the Lenstar LS 900 (Haag-Streit AG). RESULTS No statistically significant differences were noted between groups in axial length, preoperative refractive state, and in the area of capsulotomy. Circularity values were significantly better in the FS group (P=.032). We found incomplete overlap of capsulotomies in 28% of eyes in the CCC group and 11% in the FS group (P=.033). Significant correlations were noted between axial length and area of capsulotomy, and between average keratometry and area of the capsulotomy in the CCC group (R=0.278, P=.036; and R=-0.29, P=.033, respectively), but both did not correlate in the FS group (P>.05). In the CCC group, the pupillary area correlated significantly with the area of the capsulotomy (R=0.27, P=.039). Significant correlation was noted between IOL decentration and axial length in the CCC group (R=0.30, P=.026), but there was no correlation in the FS group (P>.05). CONCLUSIONS Femtosecond laser capsulorrhexis was more regularly shaped, showed better centration, and showed a better intraocular lens/capsule overlap than manual capsulorrhexis.

Central corneal volume and endothelial cell count following femtosecond laser-assisted refractive cataract surgery compared to conventional phacoemulsification

PURPOSE To compare the effect of conventional phacoemulsification and femtosecond laser-assisted cataract surgery on the cornea using Scheimpflug imaging and noncontact specular microscopy. METHODS In each group, 38 eyes (38 patients) underwent cataract surgery using either femtosecond laser-assisted (Alcon LenSx laser) (femtolaser group) or conventional phacoemulsification (phaco group). Central corneal thickness, 3-mm corneal volume, and Pentacam Nucleus Staging (PNS) were determined by a rotating Scheimpflug camera (Pentacam HR, Oculus Optikgeräte GmbH), and the volume stress index was calculated at 1 day and 1 month postoperatively. Endothelial cell count was measured by noncontact specular microscopy preoperatively, 1 day, 1 week, and 1 month postoperatively. RESULTS Central corneal thickness was significantly higher in the phaco group (607±91 μm) than in the femtolaser group (580±42 μm) on day 1, but did not differ significantly preoperatively and at 1 week and 1 month. Volume stress index at day 1 was significantly lower in the femtolaser group than in the phaco group (P<.05) but did not differ significantly at 1 month. Multivariate regression analysis showed that the type of surgery had a significant effect on central corneal thickness. CONCLUSIONS Femtosecond laser-assisted cataract surgery causes less corneal swelling in the early postoperative period and may cause less trauma to corneal endothelial cells than manual phacoemulsification.

Intraocular lens tilt and decentration measured by scheimpflug camera following manual or femtosecond laser-created continuous circular capsulotomy

PURPOSE To compare intraocular lens (IOL) decentration and tilt following a circular capsulotomy created with a femtosecond laser (laser CCC) to a manually performed continuous curvilinear capsulorrhexis (manual CCC). METHODS In a prospective, randomized study, a laser CCC (Alcon LenSx Inc) was performed in 20 eyes from 20 patients and a manual CCC was performed in 25 eyes from 25 patients. Intraocular lens decentration and tilt were measured using a Scheimpflug camera (Pentacam, Oculus Optikgeräte GmbH) 1 year after surgery. Uncorrected (UDVA) and corrected distance visual acuity (CDVA) and manifest refraction were also determined postoperatively. Between-group differences of IOL decentration and tilt as well as the correlation between IOL decentration and postoperative refractive changes and between IOL tilt and visual acuity were analyzed. RESULTS Horizontal and vertical tilt were significantly higher in the manual CCC group (P=.007 and P<.001, respectively). Lenses implanted after manual CCC showed greater horizontal and total decentration (P=.034 and P=.022, respectively). Significant differences were found in the homogeneity of dichotomized IOL vertical tilt and both horizontal and total decentration distribution (P=.008, P=.036, and P=.017, respectively). Total IOL decentration showed a significant correlation with changes in manifest refraction values between 1 month and 1 year after surgery (R=0.33, P=.032). A significant correlation was noted between IOL vertical tilt and CDVA (R(2)=0.17, β=-0.41, 95% confidence limit: -0.69 to -0.13, P=.005). CONCLUSIONS Continuous curvilinear capsulorrhexis created with a femtosecond laser resulted in a more stable refractive result and less IOL tilt and decentration than manual CCC.

Internal Aberrations and Optical Quality After Femtosecond Laser Anterior Capsulotomy in Cataract Surgery

PURPOSE To compare ocular and internal aberrations after femtosecond laser anterior capsulotomy and continuous curvilinear capsulorrhexis in cataract surgery. METHODS In this prospective study, anterior capsulotomy was performed during cataract surgery with an intraocular femtosecond (FS) laser (Alcon LenSx Inc) in 48 eyes. As a control group, continuous curvilinear capsulorrhexis (CCC) was performed in 51 eyes. Wavefront aberrometry, corneal topography, and objective visual quality were measured using the OPD-Scan (NIDEK Co Ltd). Vertical and horizontal tilt, coma, and visual quality metrics were evaluated separately to determine whether the source of aberrations was ocular or internal. Main outcome measures included postoperative residual refraction, uncorrected and corrected visual acuities, ocular and internal aberrations, Strehl ratio, and modulation transfer function (MTF). RESULTS No statistically significant differences were noted between the FS and CCC groups, respectively, in postoperative sphere (-0.60 ± 1.50 vs -0.50 ± 1.40 diopters [D]), postoperative cylinder (1.30 ± 1.01 vs 1.10 ± 1.10 D), uncorrected distance visual acuity (0.86 ± 0.15 vs 0.88 ± 0.08), or corrected distance visual acuity (0.97 ± 0.08 vs 0.97 ± 0.06). The FS group had significantly lower values of intraocular vertical tilt (-0.05 ± 0.36 vs 0.27 ± 0.57) and coma (-0.003 ± 0.11 vs 0.1 ± 0.15), and significantly higher Strehl ratios (0.02 ± 0.02 vs 0.01 ± 0.01) and MTF values at all measured cycles per degree, compared to the CCC group. CONCLUSIONS Capsulotomy performed with an intraocular FS laser induced significantly less internal aberrations measured by the NIDEK OPD-Scan aberrometer compared to eyes that underwent CCC, which may result in better optical quality after the procedure.

Evaluation of keratometric, pachymetric, and elevation parameters of keratoconic corneas with pentacam

Purpose: The purpose of this study was to evaluate the alteration of keratometric, pachymetric, and elevation parameters of keratoconic and normal corneas with the Pentacam Scheimpflug camera. Methods: Pentacam measurements were performed on 41 eyes of 24 patients with keratoconus and 70 eyes of 41 normal subjects. In each eye, keratometric values, central and minimal pachymetry, and anterior and posterior elevation were evaluated. Receiver operating characteristic curves were used to compare the sensitivity and specificity of the different parameters. Predictors of keratometric, pachymetric, and elevation data were evaluated by logistic regression analysis. Confirmatory factor analysis was performed in the keratoconus group to quantify the validity of critical parameters for keratoconus. Results: All parameters were significantly different in the keratoconus group compared with the normal control group. Receiver operating characteristic curve analyses showed the best predictive accuracy for posterior and anterior elevation (area under the curve, 0.97 and 0.96) followed by minimal and central pachymetry (0.89 and 0.88). The optimal cutoff point for posterior elevation was 15.5 μm for the discrimination of keratoconus corneas from normal. Logistic regression analysis showed best fit to the data for the model completed with the height data of the Pentacam. Confirmatory factor analysis explained a 3-factor model satisfactorily showing minimal pachymetry (-0.99), anterior elevation (0.98), and keratometry (0.95) as the most representative clinical variables of the disease. Conclusion: Posterior and anterior elevation, pachymetric, and keratometric parameters measured by the Pentacam camera can effectively discriminate keratoconus from normal corneas serving as a useful diagnostic tool for disease staging.

Effect of Femtosecond Laser Cataract Surgery on the Macula

PURPOSE To compare the effect of conventional and femtosecond laser-assisted (Alcon LenSx Inc) phacoemulsification on the macula using optical coherence tomography (OCT). METHODS Twenty eyes of 20 patients underwent uneventful cataract surgery in both study groups: femtosecond laser-assisted (laser group) and conventional phacoemulsification (control group). Macular thickness and volume were evaluated by OCT preoperatively and 1 week and 1 month postoperatively. Primary outcomes were OCT retinal thickness in 3 macular areas and total macular volume at 1 week and 1 month postoperative. Secondary outcomes were changes in retinal thickness at 1 week and 1 month postoperatively, with respect to preoperative retinal thickness values and effective phacoemulsification time. RESULTS Multivariable modeling of the effect of surgery on postoperative macular thickness showed significantly lower macular thickness in the inner retinal ring in the laser group after adjusting for age and preoperative thickness across the time course (P=.002). In the control group, the inner macular ring was significantly thicker at 1 week (mean: 21.68 μm; 95% confidence limit [CL]: 11.93-31.44 μm, P<.001). After 1 month, this difference decreased to a mean of 17.56 μm (95% CL: -3.21-38.32 μm, P=.09) and became marginally significant. CONCLUSIONS Results of this study suggest that femtosecond laser-assisted cataract extraction does not differ in postoperative macular thickness as compared with standard ultrasound phacoemulsification.

Comparison of long-term visual outcome and IOL position with a single-optic accommodating IOL After 5.5- or 6.0-mm Femtosecond laser capsulotomy.

PURPOSE To evaluate the long-term visual outcome and intraocular (IOL) position parameters with a single-optic accommodating IOL after 5.5- or 6.0-mm femtosecond laser capsulotomy. METHODS This prospective, randomized, pilot study comprised 17 eyes from 11 patients (7 men) with a mean age of 65.82±10.64 years (range: 51 to 79 years). All patients received a Crystalens AT-50AO (Bausch & Lomb) accommodating IOL after femtosecond laser refractive cataract surgery using either a 5.5-mm capsulotomy (5.5-mm group; 9 eyes) or 6.0-mm capsulotomy (6.0-mm group; 8 eyes). Near and distance visual acuities, manifest refraction spherical equivalent (MRSE), and IOL tilt and decentration were evaluated 1 year postoperatively. RESULTS No significant differences were noted between groups for postoperative uncorrected distance visual acuity, uncorrected near visual acuity, distance-corrected near visual acuity, and MRSE. Vertical and horizontal tilt were significantly higher in the 6.0-mm group than in the 5.5-mm group (P=.014 and P=.015, respectively). No significant difference was observed between groups regarding IOL decentration. CONCLUSIONS A 5.5-mm capsulotomy created with a femtosecond laser is associated with less IOL tilt and therefore may be superior to a 6.0-mm capsulotomy when implanting a single-optic accommodating IOL.

Anterior chamber characteristics of keratoconus assessed by rotating Scheimpflug imaging

PURPOSE: To compare anterior chamber parameters in normal eyes and eyes with mild to moderate keratoconus corneas using rotating Scheimpflug imaging and evaluate trends in corneal protrusion progression. SETTING: Department of Ophthalmology, Semmelweis University, Budapest, Hungary. METHODS: The anterior chamber depth (ACD) at the corneal center, thinnest point of the cornea, and 1.0 mm, 2.0 mm, and 3.0 mm paracentrally; central pachymetry; and posterior elevation were measured by Scheimpflug imaging (Pentacam) in eyes with keratoconus and eyes of refractive surgery candidates. A generalized estimating equation (GEE) was used to identify predictors of keratoconus. Correlations between posterior elevation and ACD at minimum pachymetry were analyzed by linear and piecewise linear regression. RESULTS: The keratoconus group comprised 41 eyes (24 patients) and the control group, 70 eyes (41 patients). The ACD was significantly deeper in the keratoconus group than in the control group (P<.05) and was significantly correlated with posterior elevation. In the multivariable GEE model, posterior elevation (odds ratio [OR], 1.46; P<.001) and ACD at minimum pachymetry (OR, 7.54; 95% confidence interval, 1.35‐42.05) were significant predictors of keratoconus. Segmented analysis of the correlation between posterior elevation and central ACD showed a better fit to data than linear regression and identified a 40 μm threshold level for posterior elevation. The GEE determined 450 μm as a similar threshold for central corneal thickness. CONCLUSION: There was a threshold level of posterior corneal elevation and corneal thickness values beyond which the level of corneal protrusion in keratoconus accelerated. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Corneal density with the Pentacam after photorefractive keratectomy.

PURPOSE To measure corneal density and evaluate corneal haze in unoperated eyes and in eyes after photorefractive keratectomy (PRK). METHODS Forty-nine patients (91 eyes) who underwent PRK and 48 control patients (76 unoperated eyes) were measured with the densitometry program of the Pentacam Scheimpflug imaging system (Oculus Optikgeräte GmbH) (0=no clouding, 100=tissue completely opaque). Eyes were categorized as myopic or hyperopic (myopia group and hyperopia group), with subgroups defined as unoperated (unoperated myopia group and unoperated hyperopia group), postoperative clear corneas (clear cornea myopia group and clear cornea hyperopia group), and postoperative with haze (myopia haze group and hyperopia haze group). The ANOVA option of the Statistica 8.1 program package (StatSoft Inc) was used to compare subgroups. RESULTS Maximum density of postoperative corneas with haze (myopia haze group, 46.2±16.2; hyperopia haze group, 50.2±25.8) was higher than in postoperative clear corneas (clear cornea myopia group, 29.9±8.7; clear cornea hyperopia group, 22.9±3.1), but maximum corneal density in the latter subgroups showed no difference compared with unoperated controls (unoperated myopia group, 25.1±2.4; unoperated hyperopia group, 22.8±3.2). Differences among subgroups were not found outside the 6-mm diameter ablation zone. In hazy myopic corneas, there was a strong decreasing density trend from the apex to the 3-mm radius (P<.001, R=-0.5), which continued towards the periphery at 4.5 mm (P=.019, R=-0.21). Hyperopic mild hazy corneas showed a density increase from the apex to 3 mm (P<.001, R=0.4), followed by a decrease towards the periphery (P<.01, R=-0.4). CONCLUSIONS The densitometry program of the Pentacam can provide a useful objective measure of postoperative and other mild corneal haze.