César Albarrán-Diego

Long-term comparison of corneal aberration changes after laser in situ keratomileusis: Mechanical microkeratome versus femtosecond laser flap creation

PURPOSE: To compute and compare visual acuity, refractive outcomes, and anterior corneal aberration changes after myopic laser in situ keratomileusis (LASIK) with flap creation by a mechanical microkeratome and by a femtosecond laser. SETTING: Private practice refractive surgery center, Valencia, Spain. DESIGN: Comparative case series. METHODS: Patients were assigned to have LASIK flap creation with a mechanical microkeratome (Carriazo‐Barraquer) or a femtosecond laser (IntraLase). The Visx S2 excimer laser was used for myopic ablation in all cases. Main outcome measures included uncorrected and corrected distance visual acuities and the defocus equivalent. Higher‐order aberrations (HOAs) were computed from the anterior corneal surface measured with topography for 4.0 mm and 6.0 mm pupil diameters before and 48 months after surgery. RESULTS: The study evaluated 50 patients (98 eyes). The root mean square of HOAs increased postoperatively by a factor of approximately 1.9 in both groups and with both pupil diameters. There were no statistically significant differences between the 2 groups in the increase in anterior corneal aberrations, mean postoperative visual acuity, or residual refraction. All visual and optical performance metrics remained stable throughout the 4‐year follow‐up. There were no complications with flap creation and no postoperative complications. CONCLUSIONS: The increase in anterior corneal aberrations after myopic LASIK was similar after mechanical microkeratome and femtosecond laser flap creation. Visual acuity, refraction, and the optical quality of the cornea after LASIK remained stable through 4 years postoperatively in both groups. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Combining Zonal Refractive and Diffractive Aspheric Multifocal Intraocular Lenses

PURPOSEnTo assess visual performance with the combination of a zonal refractive aspheric multifocal intraocular lens (MIOL) (Lentis Mplus, Oculentis GmbH) and a diffractive aspheric MIOL (Acri.Lisa 366, Acri.Tech GmbH).nnnMETHODSnThis prospective interventional cohort study comprised 80 eyes from 40 cataract patients (mean age: 65.5±7.3 years) who underwent implantation of the Lentis Mplus MIOL in one eye and Acri.Lisa 366 MIOL in the fellow eye. The main outcome measures were refraction; monocular and binocular uncorrected and corrected distance, intermediate, and near visual acuities; monocular and binocular defocus curves; binocular photopic contrast sensitivity function compared to a monofocal intraocular lens (IOL) control group (40 age-matched pseudophakic patients implanted with the AR-40e [Abbott Medical Optics]); and quality of vision questionnaire.nnnRESULTSnBinocular uncorrected visual acuities were 0.12 logMAR (0.76 decimal) or better at all distances measured between 6 m and 33 cm. The Lentis Mplus provided statistically significant better vision than the Acri.Lisa at distances between 2 m and 40 cm, and the Acri.Lisa provided statistically significant better vision than the Lentis Mplus at 33 cm. Binocular defocus curve showed little drop-off at intermediate distances. Photopic contrast sensitivity function for distance and near were similar to the monofocal IOL control group except for higher frequencies. Moderate glare (15%), night vision problems (12.5%), and halos (10%) were reported. Complete independence of spectacles was achieved by 92.5% of patients.nnnCONCLUSIONSnThe combination of zonal refractive aspheric and diffractive aspheric MIOLs resulted in excellent uncorrected binocular distance, intermediate, and near vision, with low incidence of significant photic phenomena and high patient satisfaction.

Visual performance of two simultaneous vision multifocal contact lenses

To evaluate and compare the visual performance of two simultaneous vision multifocal contact lenses (CLs).

Visual and optical performance with the ReZoom multifocal intraocular lens.

Purpose This study evaluated visual acuity, contrast sensitivity, and wavefront aberrations after refractive multifocal intraocular lens (IOL) implantation. Methods A prospective study comprising 174 eyes of 87 patients who had bilateral implantation of a multifocal IOL was carried out. A control group of 100 eyes of 50 age-matched patients with a monofocal IOL was used for comparison. Uncorrected and corrected distance and near visual acuity, contrast sensitivity (CS), and wavefront analysis (Hartmann-Shack) was performed 6 months after surgery. Contrast sensitivity was tested for distance and near under mesopic (2 cd/m2) and photopic conditions (90 cd/m2). Results Distance photopic CS was not significantly different from the monofocal group, while distant mesopic CS and near photopic and mesopic CS were significantly lower. Mean aberration root mean square (RMS) values for the multifocal IOL group were 0.229±0.103 µm for coma, 0.137±0.067 µm for spherical aberration (SA), and 0.301±0.133 µm for higher order aberrations (HOAs). Strehl ratio averaged 0.096±0.045. Conclusions Distant visual performance with the multifocal IOL was excellent under photopic conditions, but was reduced under mesopic levels. Near vision showed suboptimal results in both photopic and mesopic conditions. Coma, SA, and HOAs with the multifocal IOL were higher than those reported previously, with a lower Strehl ratio.

Optical quality comparison between spherical and aspheric toric intraocular lenses

Purpose To measure and compare the optical quality of spherical and aspheric toric intraocular lenses (IOLs). Methods Wavefront aberrations of AcrySof Toric and IQ Toric IOLs (Alcon Laboratories) for different powers were measured at 3- and 5-mm pupils by Nimo TR0805 instrument. The Zernike coefficients of trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were evaluated. The point spread functions (PSFs) of each IOL evaluated were calculated from the wavefront aberrations. The PSF images also were calculated from the IOL wavefront aberrations, adding the corneas aberrations to simulate the optical quality after their implantation. Results Spherical toric IOLs showed positive and aspheric toric IOLs negative spherical aberrations. Statistically significant differences were found in spherical aberration root mean square (RMS) values between spherical and aspheric IOLs for both pupil sizes (p<0.05). Aspheric toric IOLs showed higher spherical aberration RMS values. We found differences in PSF images between both IOL designs at 5-mm pupil. The PSFs corresponding to the aspheric toric IOLs showed more spread out than the PSFs corresponding to the spherical toric IOLs. However, when corneal aberrations were added, aspheric toric IOLs showed better optical quality than spherical toric IOLs. Conclusions At 3-mm pupil, the optical quality between the IOL designs was similar, but at 5-mm pupil the optical quality was higher for spherical IOLs than aspheric IOLs. However, when theoretical corneal aberrations were added, aspheric toric IOLs showed better optical quality than spherical toric IOLs, due to the compensation between aspheric toric IOL negative spherical aberration and corneal positive spherical aberration.

Corneal thickness differences between sexes after oxybuprocaine eye drops.

Purpose We aimed to analyze the corneal thickness (CT) values of female and male subjects before and after instillation of oxybuprocaine 0.4% anesthetic eye drops. Methods The CT of 30 female subjects and 28 male subjects was measured using scanning-slit corneal topography (Orbscan Topography System II, Orbscan, Inc, Salt Lake City, UT). Measurements were carried out before and 3 minutes after the instillation of oxybuprocaine 0.4% eye drops. Results The difference between the baseline values and those obtained after anesthesia ranged as follows: male subjects: central, −26 to +24 &mgr;m; superior, −24 to +23 &mgr;m; inferior, −19 to +20 &mgr;m; nasal, −25 to +30 &mgr;m; and temporal, −21 to +20 &mgr;m; female subjects: central, −16 to +24 &mgr;m; superior, −19 to +32 &mgr;m; inferior, −14 to +34 &mgr;m; nasal, −19 to +33 &mgr;m; and temporal, −36 to +16 &mgr;m. No significant differences were found in any corneal location in male subjects. The differences were significant at inferior (p = 0.001) and nasal (p = 0.011) corneal sites in female subjects. Conclusions Oxybuprocaine anesthetic eye drops induce significant CT increases in female subjects but not in male subjects.

Intrasubject repeatability of corneal power, thickness, and wavefront aberrations with a new version of a dual rotating Scheimpflug–Placido system

Purpose To determine the intrasubject repeatability of a recently introduced dual‐camera rotating Scheimpflug–Placido imaging system (Galilei G4) in determining corneal thickness, power, and wavefront aberrations in young healthy subjects. Setting University of Valencia, Valencia, Spain. Design Prospective evaluation of diagnostic technology. Methods The study comprised right eyes of 25 subjects aged 20 to 40 years with a spherical equivalent ranging from −4.25 to +1.00 diopters. The central corneal thickness, thinnest point value and location, anterior and posterior surface curvatures, total corneal power, and corneal wavefront aberrations were measured for distance vision using the dual Scheimpflug–Placido system. Three consecutive measurements were taken in each eye. Results Twenty‐five eyes were evaluated. Repeated‐measures analysis of variance showed the only statistically significant difference between the 3 repeated measures to be in trefoil aberration. Intraclass correlation coefficients (ICCs) were higher than 0.950 for all the parameters except the thinnest point chord distance to geometric corneal center (0.528) and chord angle (0.742), corneal astigmatism (0.811) and its vector components J0 (0.891) and J45 (0.724), and all wavefront aberrations. Conclusions The new dual Scheimpflug–Placido system had high intraobserver repeatability for corneal power and thickness and moderate repeatability for corneal astigmatism and corneal wavefront aberrations in healthy corneas with low astigmatism. This iteration of the device performed better in young healthy corneas than preceding versions. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Visual performance comparison between contact lens-based pinhole and simultaneous vision contact lenses

The aim was to evaluate the visual performance provided with a contact lens‐based pinhole design against a simultaneous vision multifocal contact lens.

Iris-fixated toric phakic intraocular lens for myopic astigmatism

PURPOSE: To evaluate the efficacy, predictability, safety, stability, and complications of the Artiflex toric iris‐fixated phakic intraocular lens (pIOL) for myopic astigmatism. SETTING: Private practice surgery centers, Valencia and Terrassa, Spain. DESIGN: Cohort study. METHODS: At 12 months, refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, complications, pIOL misalignment, and endothelial cell count (ECC) were evaluated. Indices of success and misalignment were calculated using vector analysis. RESULTS: The study enrolled 42 eyes in 25 patients aged 21 to 39 years. The mean spherical equivalent decreased from −8.85 diopters (D) ± 2.71 (SD) to −0.37 ± 0.46 D, with 66.7% of the eyes within ±0.50 D. The mean cylinder power decreased from −2.90 D (range −1.50 to −5.00 D) to −0.39 D (range 0.00 to −1.50 D); refraction was highly stable. All eyes achieved a decimal UDVA of 0.5 or better and a CDVA of 0.8 or better. A gain of 1 line or more of CDVA was found in 69.1% of eyes. The mean clinical pIOL misalignment was 2.6 ± 1.8 degrees; 1 eye (2.4%) required surgical repositioning of the pIOL. The mean ECC decrease was 9.3% ± 1.8%; iris pigment precipitates were observed in 16.7% of eyes. Vector analysis showed excellent mean indices of success for overall (0.94 ± 0.04), spherical (0.96 ± 0.05), and astigmatic (0.95 ± 0.16) corrections; the mean angle of error was 1.8 ± 2.7 degrees. CONCLUSION: Implantation of the toric pIOL was effective, predictable, safe, and stable for the correction of myopic astigmatism. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Contrast sensitivity after refractive lens exchange with a multifocal diffractive aspheric intraocular lens

PURPOSEnTo evaluate distance and near contrast sensitivity (CS) under photopic and mesopic conditions before and after refractive lens exchange (RLE) and implantation of the aspheric AcrySofReSTOR (SN6AD3 model) intraocular lens (IOL).nnnMETHODSnSeventy-four eyes of 37 patients after RLE underwent bilateral implantation with the aspheric AcrySof ReSTOR IOL. The patient sample was divided into myopic and hyperopic groups. Monocular uncorrected visual acuity at distance and near (UCVA and UCNVA, respectively) and monocular best corrected visual acuity at distance and near (BCVA and BCNVA, respectively) were measured before and 6 months postoperatively. Monocular CS function was measured at three different luminance levels (85, 5 and 2.5 cd/m²) before and after RLE. Post-implantation results at 6 months were compared with those found before surgery.nnnRESULTSnOur results revealed that patients in both groups obtained good UCVA and BCVA after RLE at distance and near vision in relation to pre-surgery values. No statistically significant differences were found between the values of CS pre and post-RLE at distance and near, at any lighting condition and spatial frequency (p>0.002).nnnCONCLUSIONSnRefractive lens exchange with aspheric AcrySof ReSTOR IOL in myopic and hyperopic population provided good visual function and yield good distance and near CS under photopic and mesopic conditions.