Safety and efficacy of a small-aperture capsular bag-fixated intraocular lens in eyes with severe corneal irregularities.

PURPOSE: To implant a small-aperture intraocular lens (IOL) (IC-8) in eyes with severe corneal irregularities to reduce higher-order aberrations and provide better central visual acuity. SETTING: University Hospital, LMU Munich, Germany. DESIGN: Prospective nonrandomized interventional case series. METHODS: Eyes with severe corneal irregularities due to keratoconus, previous penetrating keratoplasty, status postradial keratotomy, or scarring after ocular trauma were enrolled. Exclusion criteria were progressive keratoconus, pseudoexfoliation, glaucoma, maculopathy, reduced endothelial cells (<1800 cells/mm), and central corneal opacity. Conventional phacoemulsification with implantation of the small-aperture IOL was performed. The primary efficacy endpoint was corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), and uncorrected near visual acuity (UNVA). Secondary endpoints were life quality assessment using the Visual Function Questionnaire-25 and determination of the refractive defocus curve. RESULTS: Seventeen eyes of 17 patients were enrolled. In all 17 patients, CDVA improved from 0.37 ± 0.09 to 0.19 ± 0.06 logarithm of the minimum angle of resolution (logMAR) 3 months postoperatively (P < .0001). Similarly, postoperative UDVA, UIVA, and UNVA improved significantly in 100%, 88%, and 88%, respectively. The defocus curve showed best results at 0.17 logMAR with a defocus of -0.5 diopter. In addition, overall life quality analyses reported less difficulty with activities under reduced optical phenomena conditions. CONCLUSIONS: The small-aperture IOL was a useful option in eyes with severe corneal irregularities, had a high safety index and a high satisfaction rate, and can lead to better visual quality in these cases. Further studies are needed to improve power calculation of this IOL.

Application of Purkinje images for pinhole pupilloplasty and relevance to chord length mu.

PURPOSE: To evaluate the results of pinhole pupilloplasty in cases with high astigmatism and higher-order aberrations (HOAs). SETTING: Dr. Agarwal's Eye Hospital & Research Centre, Chennai. DESIGN: Case series. METHODS: Pinhole pupilloplasty was performed based on the Purkinje 1 (P1) images formed from the light source of a Lumera surgical microscope; the images served as a reference marker for centration. A single-pass 4-throw technique was used to achieve a pinhole pupil. The preoperative and postoperative pupil diameter, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, simulated keratometry (K), and chord length mu (µ) were assessed, the latter using a Pentacam rotating Scheimpflug camera. RESULTS: Pinhole pupilloplasty was performed in 8 eyes (8 patients). There was a statistically significant reduction in the mean horizontal and vertical pupil diameters and in the mean pupil diameter from preoperatively to postoperatively (both P < .001). Although the improvement in UDVA was statistically significant (P < .001), the change in CDVA was not. The mean simulated K and mean chord length µ values were significantly lower postoperatively (P = .024 and P < .001, respectively). The reduction in pupil size was more apparent than the reduction in chord length µ. The correlation between the change in chord length µ and the change in pupil size was not significant (r = -0.067, P = .874). The pupil was well centered on the P1 images. No major adverse events or complications occurred postoperatively. CONCLUSION: Postoperative results showed a correlation between the improvement in visual acuity and the decrease in pupil size and chord length µ.

Analysis of corneal higher-order aberrations in cataract patients with high myopia.

PURPOSE: To evaluate the differences in corneal higher-order aberrations (HOAs) between cataract patients with high axial myopia and normal cataract patients, and to identify the associated factors. SETTING: Department of Ophthalmology and Vision Science of the Eye and ENT Hospital of Fudan University, Shanghai, China. DESIGN: Retrospective case series. METHODS: Corneal aberrations and axial lengths (ALs) were measured using a rotating Scheimpflug camera (Pentacam) and partial coherence interferometry (IOLMaster) in the high myopia group and the control group. RESULTS: The study comprised 287 patients (520 eyes). There were 194 eyes in the high myopia group and 326 eyes in the control group. The 5 anterior corneal aberrations-vertical coma, vertical trefoil, horizontal coma, oblique trefoil, and primary spherical aberration-in the high myopia group were 0.07 µm ± 0.38 (SD), -0.11 ± 0.23 µm, 0.07 ± 0.28 µm, -0.02 ± 0.18 µm, and 0.39 ± 0.19 µm, respectively. No negative primary spherical aberrations of the total or anterior corneal surface were found in the high myopia group. Differences between the 2 groups were found in terms of central corneal thickness, astigmatism, primary spherical aberration, vertical coma, and oblique trefoil; however, these differences were not consistent between different age subgroups. Higher-order aberrations were correlated with age. Posterior corneal vertical coma was correlated with AL (Pearson correlation = -0.188, P = .047). CONCLUSIONS: Negative primary spherical aberrations of the anterior or total corneal surface were not found in the high myopia group. Age showed a strong relationship with HOAs. For cataract patients with high myopia, aspheric intraocular lens implantation is recommended.

Extended depth of focus contact lenses vs. two commercial multifocals: Part 1. Optical performance evaluation via computed through-focus retinal image quality metrics / Lentes de contacto de profundidad de foco extendido vs. dos lentes multifocales comerciales: Parte 1. Evaluación del rendimiento óptico del enfoque computarizado mediante métricas de calidad de imagen retinianas

Purpose: To compare the computed optical performance of prototype lenses designed using deliberate manipulation of higher-order spherical aberrations to extend depth-of-focus (EDOF) with two commercial multifocals. Methods: Emmetropic, presbyopic, schematic eyes were coupled with prototype EDOF and commercial multifocal lenses (Acuvue Oasys for presbyopia, AOP, Johnson & Johnson & Air Optix Aqua multifocal, AOMF, Alcon). For each test configuration, the through-focus retinal image quality (TFRIQ) values were computed over 21 vergences, ranging from -0.50 to 2.00 D, in 0.125 D steps. Analysis was performed considering eyes with three different inherent aberration profiles: five different pupils and five different lens decentration levels. Results: Except the LOW design, the AOP lenses offered ‘bifocal’ like TFRIQ performance. Lens performance was relatively independent to pupil and aberrations but not centration. Contrastingly, AOMF demonstrated distance centric performance, most dominant in LOW followed by MED and HIGH designs. AOMF lenses were the most sensitive to pupil, aberrations and centration. The prototypes demonstrated a ‘lift-off’ in the TFRIQ performance, particularly at intermediate and near, without trading performance at distance. When compared with AOP and AOMF, EDOF lenses demonstrated reduced sensitivity to pupil, aberrations and centration. Conclusion: With the through focus retinal image quality as the gauge of optical performance, we demonstrated that the prototype EDOF designs were less susceptible to variations in pupil, inherent ocular aberrations and decentration, compared to the commercial designs. To ascertain whether these incremental improvements translate to a clinically palpable outcome requires investigation through human trials (AU)

Objetivo: Comparar el rendimiento óptico computado de los prototipos de lentes de contacto diseñadas mediante manipulación deliberada de aberraciones esféricas de alto orden para conseguir la profundidad de foco extendida (EDOF) con dos lentes multifocales comerciales. Métodos: Se adaptaron lentes de contacto con prototipo EDOF, y lentes multifocales comerciales a ojos esquemáticos présbitas emétropes (Acuvue Oasys para presbicia, AOP, Johnson & Johnson & Air Optix Aqua multifocal, AOMF, Alcon). Para cada configuración de la prueba se obtuvieron los valores de la calidad de imagen de la retina a través del foco (TFRIQ) en 21 vergencias, que oscilaron entre -0,5 y 2D, en pasos de 0,125D. Se llevó a cabo el análisis considerando los ojos con tres perfiles de aberración diferentes: cinco pupilas diferentes y cinco niveles de descentramiento de lentes distintos. Resultados: Exceptuando el diseño LOW, las lentes AOP aportaron un rendimiento TFRIQ de tipo ‘bifocal’. El desempeño de las lentes fue relativamente independiente de la pupila y aberraciones, pero no del descentramiento. Por contra, AOMF demostró un rendimiento céntrico en visión lejana, más dominante en el diseño LOW, seguido de los diseños MED y HIGH. Las lentes AOMF fueron más sensibles a la pupila, aberraciones y centrado. Los prototipos demostraron un efecto de mejora en el rendimiento TFRIQ, particularmente en visión intermedia y próxima, sin pérdida de rendimiento en visión lejana. Al compararlas con las lentes AOP y AOMF, las lentes EDOF demostraron una reducción de la sensibilidad al factor pupila, las aberraciones y el centrado. Conclusión: Con la calidad de imagen de la retina a través del foco, como medida del rendimiento óptico, demostramos que los diseños del prototipo EDOF fueron menos susceptibles a las variaciones de la pupila, las aberraciones oculares inherentes, y al descentramiento, en comparación a los diseños comerciales. Se precisa más investigación futura, mediante ensayos en humanos, para verificar si estas mejoras incrementales se trasladan a resultados clínicamente evaluables (AU)

Refractive outcome of wavefront guided laser in situ keratomileusis and wavefront guided photorefractive keratectomy in high pre-existing higher order aberration.

PURPOSE: To compare visual outcome and higher order aberrations (HOA) between wavefront-guided LASIK (WF-LASIK) and wavefront guided PRK (WF-PRK) in patients with high preoperative HOA. METHODS: Randomized prospective interventional study. Conducted at Guru Nanak Eye Centre, Maulana Azad Medical College, Delhi, India. Eighty myopic eyes of forty patients were included. INCLUSION CRITERIA: age more than 21 years, best corrected visual acuity of 20/20 or better, a stable refraction, to be off soft contact lens for minimum 14 days prior to preoperative examination, preoperative RMS HOA more than 0.35 µ, preoperative central corneal thickness at least 500 µm, estimated residual stromal bed thickness of at least 275 µm in patients undergoing WF-LASIK and 350 µm in patients undergoing WF-PRK. Exclusion criteria were severe dry eye, blepharitis, corneal disease and warpage, uveitis, posterior segment abnormalities involving the macula or optic nerve and systemic diseases. Patients were randomly divided into two groups. They underwent either WF-LASIK (group A) or WF-PRK (group B) over 2 years (40 eyes each). Patients were followed up for 6 months. Main outcome measures were efficacy, safety, stability, predictability and HOA. RESULTS: At 6 months mean uncorrected visual acuity (logMAR) in group A was -0.01 ± 0.04 and group B was 0.00 ± 0.07 (P = 0.23). HOA RMS (6mm pupil) in group A was 0.61 ± 0.24 µm and group B was 0.55 ± 0.25 µm. The increase was statistically significant in both the groups (P < 0.05). Both the groups showed similar efficacy, predictability and safety. CONCLUSION: WF-LASIK and WF-PRK have similar efficacy, safety and predictability, though WF-PRK induces less HOA.

Higher order ocular aberrations and their relation to refractive error and ocular biometry in children.

PURPOSE: The interaction between higher order ocular aberrations (HOA) and refractive error is not yet fully understood. This study investigated HOA in relation to refractive error and ocular biometric parameters in a population with a high prevalence of ametropia. METHODS: The HOA were investigated in two cohorts of Caucasian children aged 9 to 10 and 15 to 16 years (n = 313). These aberrations were measured for a 5-mm pupil with the IRX3 aberrometer. Cycloplegic refractive error and ocular biometry measures, including axial length and corneal curvature, also were assessed with the Shin-Nippon SRW-5000 auto-refractor and Zeiss IOLMaster, respectively. Participants were divided into refractive groups for analysis of HOA. RESULTS: The magnitude of total HOA was higher in this population at 0.27 µm (interquartile range [IQR], 0.22-0.32 µm) than other HOA reported in the literature. The profile of HOA was not significantly different across the two age cohorts or across refractive groups, nor did spherical aberration differ significantly with age (Z4° = 0.07 µm for both cohorts). Multivariate linear regression analysis demonstrated spherical aberration was significantly related to axial length (but not refractive grouping), with longer eyes having less positive values of fourth order and root mean square (RMS) spherical aberration. CONCLUSIONS: This study found no significant difference in HOA across refractive groups. The current study also highlights the importance of knowledge of axial length when analyzing HOA.

Intraoperative, real-time aberrometry during refractive cataract surgery with a sequentially shifting wavefront device.

PURPOSE: To introduce a new sequential wavefront device with rapid sampling that can be used as an intraoperative, real-time aberrometer/refractometer for immediate diagnosis and management of refractive outcomes during cataract surgery. METHODS: A unique wavefront device uses a rotating prismatic mirror to rapidly shift the incident wavefront emanating from the eye through an aperture for analysis of a sequentially sampled wavefront segment. The sampled segment is then focused onto a quad detector that localizes its angular displacement of the sampled segment's wavefront gradient. Although the device's capability is higher for other applications, the wavefront is herein rapidly sampled at 200 Hz (frames/second), with a 2-mm aperture that moves along a 5-mm outer diameter annulus to capture a real-time analysis of refractive error for intraoperative application (ie, an intraoperative wavefront movie). The prototype wavefront device has been miniaturized into a narrow profile attachment that can be fixed to an operating microscope. In pilot analysis, several eyes undergoing cataract surgery were analyzed to determine both the qualitative and quantitative change in refraction with surgical intervention in an effort to document and improve outcomes intraoperatively. RESULTS: Clinical application of the device was easily implemented without changing or limiting the working distance, magnification, or illumination of the surgeon's ergonomics intraoperatively. The real-time wavefront outcome was visualized overlaying a live eye image, presenting the refractive error both qualitatively and quantitatively. Qualitative representation of spherical refractive error was seen as a circle, cylinder as a thin ellipse, and emmetropia as a dot. Localization of lower-order aberrations with a practical sample rate of 200 frames/ second enables a real-time visualization of qualitative refractive data coaxially aligned with the eye image and quantitatively as sphere, cylinder, and axis at the bottom of the screen. Practical evaluation of residual cylinder prior to and during limbal relaxing incision placement, rotational accuracy during toric intraocular lens alignment, and refractive effect of subtle surgical maneuvers were all achieved with this device. CONCLUSION: Real-time, intraoperative refraction and visualization is possible with a new sequential wavefront device attached to the operating microscope. The precision and accuracy of intraoperative documentation and refinement of outcomes is likely to be enhanced, making this an important future tool for optimizing cataract surgery outcomes.

The influence of intraocular pressure on wavefront aberrations in patients undergoing laser-assisted in situ keratomileusis.

PURPOSE: To investigate the effect of intraocular pressure (IOP) on wavefront aberrations in the anterior cornea, the internal optics, and the whole eye for myopic patients undergoing laser-assisted in situ keratomileusis (LASIK) surgery. METHODS: Fifty-seven myopic subjects were tested for wavefront aberrations in the anterior corneal surface and the whole eye using a corneal topographer and a wavefront analyzer, respectively, pre- and post-LASIK. The IOP and central corneal thickness (CCT) were measured with a noncontact tonometer and a pachymeter, respectively. Pre- and postoperative wavefront aberrations were compared, and the correlation between changes in the Zernike aberrations and the IOP was statistically tested. RESULTS: The mean root mean square (RMS) values of the higher-order aberrations (HOAs) were significantly increased in the anterior cornea, the internal optics, and the whole eye. The mean RMS values for a majority of Zernike terms were significantly increased, and systematic increases in the spherical aberrations were found in both the cornea and the whole eye. The spherical aberrations after LASIK were significantly correlated to the IOP (r = 0.59, P < 0.01, for oculus dexter [OD, right eye] and r = 0.49, P < 0.01, for oculus sinister [OS, left eye] in the cornea; r = 0.38, P < 0.01, for OD and r = 0.46, P < 0.01, for OS in the whole eye). CONCLUSIONS: IOP contributes to LASIK-induced HOAs, particularly spherical aberrations. To control the HOAs after LASIK, a new algorithm should include the IOP as a variable for laser surgery.

Adapting to blur produced by ocular high-order aberrations.

The perceived focus of an image can be strongly biased by prior adaptation to a blurred or sharpened image. We examined whether these adaptation effects can occur for the natural patterns of retinal image blur produced by high-order aberrations (HOAs) in the optics of the eye. Focus judgments were measured for 4 subjects to estimate in a forced choice procedure (sharp/blurred) their neutral point after adaptation to different levels of blur produced by scaled increases or decreases in their HOAs. The optical blur was simulated by convolution of the PSFs from the 4 different HOA patterns, with Zernike coefficients (excluding tilt, defocus, and astigmatism) multiplied by a factor between 0 (diffraction limited) and 2 (double amount of natural blur). Observers viewed the images through an Adaptive Optics system that corrected their aberrations and made settings under neutral adaptation to a gray field or after adapting to 5 different blur levels. All subjects adapted to changes in the level of blur imposed by HOA regardless of which observer's HOA was used to generate the stimuli, with the perceived neutral point proportional to the amount of blur in the adapting image.

Effects of pterygium on ocular aberrations.

PURPOSE: To compare high-order aberration between the eyes with pterygium and normal fellow eyes. SETTING: Ophthalmic Research Center and Department of Ophthalmology Labbafinejad Medical Center Shahid Beheshti University of Medical Sciences Tehran, Iran. METHOD: This comparative cross-sectional study comprised 31 patients with unilateral pterygium. NIDEK OPD-Scan wavefront aberrometry was performed in all patients in both eyes. Then, aberometric parameters were compared between the eyes. RESULTS: Sixty-two eyes of 31 patients (23 men and 8 women) with a mean age of 42.5 ± 5.9 years were included in the study. Root mean square (RMS) of total higher-order aberration increased statistically significantly in the involved eyes compared with normal fellow eyes (1.85 ± 2.22 and 0.36 ± 0.44 µm; P = 0.001). All RMS of Zernike orders and all RMS of different aberrations were higher in the involved eyes group and were statistically significant except for spherical aberration. The most significant differences belonged to RMS of total trefoil (1.37 vs. 0.25 µm) and RMS of total coma (0.37 vs. 0.14 µm) (P = 0.0001). With decreasing the uninvolved optical zone (increasing the size of pterygium), RMS of all aberrations increased and the differences were statistically significant except for spherical aberration. CONCLUSION: Pterygium and its size have significant influence on high-order aberrations of the eye especially on measured total coma and total trefoil in compared with normal fellow eye.

Outcomes of corneal spherical aberration-guided cataract surgery measured by the OPD-scan.

PURPOSE: To determine based on preoperative corneal spherical aberration, the practicality of targeting zero total ocular postoperative spherical aberration when selecting an aspheric intraocular lens (IOL). METHODS: Consecutive cataract patients were selected to receive an aspheric IOL based on corneal spherical aberration. A target of zero postoperative total spherical aberration Z(4,0) was calculated. One of three IOLs was chosen, based on the corneal spherical aberration Z(4,0) measurement at the 6-mm optical zone. The IOL was selected based on the summation of the corneal spherical aberration and the aspheric value of the prolate optic. The intention was an absolute value of zero total spherical aberration. Statistical analysis of the postoperative total ocular wavefront profile was performed to assess the accuracy of aspheric IOL selection. RESULTS: Forty eyes of 40 patients were available for postoperative assessment. The Tecnis Z9003 (Abbott Medical Optics) was implanted in 25 eyes with a preoperative corneal spherical aberration of +0.311±0.054 µm, the AcrySof IQ (Alcon Laboratories Inc) in 13 eyes (+0.188±0.034 µm), and the SofPort-Advanced Optic with Violet Shield (Bausch & Lomb) was implanted in 2 eyes (+0.0915 µm). Total postoperative ocular spherical aberration for the entire group measured +0.019±0.051 µm (Tecnis: +0.024±0.058 µm; AcrySof IQ: +0.010±0.035 µm; and SofPort AOV: +0.037 µm). Mean absolute predictive error, for the entire group, measured +0.025±0.020 µm. CONCLUSIONS: Skiascopy-derived total wavefront measurement of spherical aberration is a reproducible method of aspheric IOL selection and permits more precise control of total ocular spherical aberration.

Corneal thickness association with ocular and corneal high-order aberrations.

PURPOSE: To investigate the association among central corneal thickness, peripheral corneal thickness (PCT), and wavefront aberrations in the anterior cornea, posterior cornea and the whole eye in myopia. METHODS: Sixty-four eyes of 64 myopic subjects were evaluated with a Pentacam rotating Scheimpflug camera (Oculus, Inc., WA) corneal topographer for: (1) wavefront aberrations from the anterior and posterior corneal surface, (2) corneal thickness (central and peripheral), and (3) with a wavefront aberration-supported cornea ablation wavefront analyzer (Wavescan, Visx, Inc., Santa Clara, CA) for wavefront aberrations generated in the whole eye. Relationships between the wavefront aberrations and corneal thickness were analyzed. RESULTS: The mean age of subjects was 34.75 +/- 10.08 years. The central corneal thickness was 550.5 +/- 28.459 microm. The mean peripheral thickness was 629.9 +/- 32.1 microm. Central and PCTs were not significantly correlated with corneal or ocular high-order aberrations. Intraocular pressure was significantly correlated with ocular trefoil (r = -0.307, P=0.001). CONCLUSIONS: Central and PCT were not significantly associated with either anterior or posterior corneal Zernike aberrations; in addition, no association with the whole ocular wavefront aberrations was found.