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Larissa Gouvea,1,2 Kareem Sioufi,3 Colin E Brown,3 George Waring IV,4 Wallace Chamon,2 Karolinne Maia Rocha3 1Department of Ophthalmology and Visual Sciences, University of Toronto, Toronto, ON, Canada; 2Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo, Brazil; 3Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA; 4Waring Vision Institute, Mount Pleasant, SC, USACorrespondence: Larissa Gouvea Toronto Western Hospital - 399 Bathurst Street, 6th Floor East Wing, Reception 1, Toronto, ON, M5T 2S8, CanadaTel +1 416 603-5401Fax +1 416 603-1993Email gouveaalarissa@gmail.comPurpose: To compare the refractive predictability of intraoperative aberrometry (IA, ORA, Alcon) and Barrett True-K/Universal II formulas for intraocular lens (IOL) power calculations in post-corneal refractive surgery and normal eyes.Methods: Retrospective study of normal and post-corneal refractive surgery eyes that underwent cataract surgery with IA at tertiary academic center. Preoperatively, IOL power calculations were performed using Barrett Universal II (normal eyes) or Barrett True-K (post-corneal refractive surgery eyes) formulas. Intraoperatively, aphakic IA measurements were used for IOL power calculations. Mean absolute refractive prediction error (MAE) and the percentage of eyes with prediction error within ± 0.50, ± 0.75 and ± 1.00 D were calculated. Refractive predictability was also evaluated in short, normal, and long eyes.Results: Two hundred and seventy-three eyes were included in the analysis. No statistically significant differences were observed between the MAE of preoperative formulas and IA for post-hyperopic laser vision correction (LVC), post-myopic LVC, post-radial keratotomy (RK) and normal eyes. For prediction error within ± 0.5 D in post-corneal refractive surgery eyes, range of agreement between Barrett True-K and IA ranged from 28% (7/25) of the time in post-RK eyes to 49% (40/81) of the time in post-hyperopic LVC; the corresponding value for Barrett Universal II/IA was 62% (64/103) in normal eyes. When there was disagreement, IA outperformed Barrett True-K in post-hyperopic LVC eyes and Barrett formula outperformed IA in post-myopic LVC, post-RK, and normal eyes.Conclusion: IA appears to be comparable to Barrett formulas for IOL power calculations in post-corneal refractive surgery and normal eyes. In post-hyperopic LVC, IA yields better results compared to Barrett True-K formula; in real-life scenarios, IA reveals statistical advantage over the Barrett True-K no history formula for eyes post-hyperopic LVC.Keywords: intraoperative aberrometry, eyes post refractive surgery, refractive outcomes, Barrett True-K formula

PURPOSE: To evaluate an automated method for detecting the cone shape characteristics and to assess the cornea specialists' subjective variability of these measures using different maps. METHODS: Topographic images of the anterior and posterior surface of each eye were presented to 12 clinicians in two different types of map: tangential curvature and relative elevation to the best-fit sphere. They were asked to mark the cone center and its boundaries in the two maps without knowing that they belonged to the same patient. The results between the maps were compared to assess the subjective variability dependent on the map type and the automated method was compared against both estimations to assess its accuracy. RESULTS: Considering the results of anterior and posterior surfaces, there was low agreement between the cone center estimations using different types of maps for 10 of the 12 cases ( P < .05), whereas the comparison between the automated method and the two map estimations did not show differences in 11 of the 12 cases ( P > .05). There was high variability, up to 55%, among clinicians' estimations of the cone area. The results of the automated method were within the range of the expert's estimations. CONCLUSIONS: An objective, mathematically derived method of determining morphological dimensions of the cone was consistent with clinicians' evaluations. Although there was high variability among the experts' subjective estimates, which were highly influenced by the type of map, the objective method provided a reliable evaluation of the keratoconus shape independent of maps or color scale. [ J Refract Surg . 2021;37(6):414–421.]

PURPOSE To analyze factors affecting depth of focus (DOF) and near vision functionality in eyes implanted with aspheric monofocal intraocular lenses (IOLs). METHODS This prospective study included 111 eyes of 74 patients that underwent phacoemulsification with monofocal IOL implantation. Ninety-one normal eyes were randomized to receive aberration-free (n = 30) or negative-spherical aberration (SA) IOLs (n = 61). Twenty post-hyperopic femto-LASIK eyes received aberration-free IOLs. Corneal higher-order aberrations (SA, coma, trefoil, and corneal asphericity) for a 6 mm pupil were measured by Scheimpflug tomography. Ray-tracing metrics (visual Strehl optical transfer function [VSOTF], effective range of focus [EROF], sphere shift [SS], EROF-SS), pupil size measurements at far and near, and ocular and corneal SA were obtained using ray-tracing aberrometry. Distance-corrected near visual acuity (DCNVA) and subjective defocus curves up to ±4.0 diopters were evaluated. RESULTS Multivariable logistic regression found corneal profile and IOL type to be determinants of extended DOF with monofocal IOLs. The aberration-free IOL group showed significantly better DCNVA and higher total SA than the negative-SA group. Post-hyperopic LASIK eyes showed significantly better DCNVA; higher negative SA, coma, and Q value (P < .05), and smaller pupil size (P = .05) than normal eyes implanted with aberration-free IOLs. CONCLUSION Corneal profile and type of IOL implanted were the most important factors influencing near vision functionality with aspheric monofocal IOLs. Higher positive SA in the aberration-free group potentially led to better DCNVA than the negative-SA group in normal eyes. Hyperprolate corneas had better DOF curves and DCNVA than normal corneas. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

PURPOSE: To compare ray-tracing aberrometry, Hartmann-Shack wavefront analysis, automated refraction, and manifest refraction in patients with echelette diffractive intraocular lenses (IOLs) and patients with monofocal IOLs with negative spherical aberration. METHODS: Pseudophakic patients implanted with an echelette diffractive IOL (Tecnis ZXR00; Johnson & Johnson Vision) and a control group consisting of patients implanted with a negative spherical aberration monofocal IOL (Tecnis ZCBOO, Johnson & Johnson Vision) were included in this study. Ray-tracing aberrometry (iTrace; Tracey Technologies Corp.), Hartmann-Shack wavefront analysis (LADARWave; Alcon Laboratories, Inc.), automated refraction (Topcon KR-8800; Topcon Medical Systems, Inc.), and manifest refraction spherical equivalent were performed 1 to 3 months postoperatively. RESULTS: Thirty-two eyes implanted with a ZXR00 IOL and 30 eyes implanted with a ZCBOO IOL were enrolled in this study. The ZXR00 IOL group yielded more myopic results with automated refactions (−0.62 ± 0.41 diopters [D]), Hartmann-Shack wavefront analysis (−0.85 ± 0.40 D), and ray-tracing aberrometry (−0.45 ± 0.64 D), compared to manifest refraction (−0.12 ± 0.44 D) ( P < .001). Hartmann-Shack wavefront analysis showed a statistically significant myopic shift (−0.39 ± 0.47 D) in the ZCBOO group compared to ray-tracing aberrometry, automated refraction, and manifest refraction spherical equivalent (−0.14 ± 0.56, −0.14 ± 0.50, and −0.06 ± 0.44 D, respectively; P < .001). CONCLUSIONS: Manifest refraction techniques unique to echelette technology should be used to avoid over-minus end points. Autorefractors and aberrometers commonly use near-infrared light; thus, myopic results are expected with echelette achromatic technology. [ J Refract Surg . 2020;36(5):334–339.]

The term dysfunctional lens syndrome has gained acceptance in the field and encompasses natural changes due to aging of crystalline lens. The evolution of diagnostic devices has been a key factor in better staging, understanding and characterizing of these degenerative changes. Even with these technological advances and the use of subjective classifications, such as the classic Lens Opacities Classification System, an objective staging of early dysfunctional lens syndrome has yet to be established. Ocular wavefront aberrometry and objective scatter index, associated with Scheimpflug backscatter densitometry, have proven instrumental in detecting early dysfunctional lens syndrome. Staging of early dysfunctional lens syndrome has been proposed in the literature, but no classification has been recognized worldwide. The purpose of this literature review is to assess the current state of dysfunctional lens syndrome from a technological perspective and propose a new staging system to assist surgeons in making surgical decisions. RESUMO O termo “síndrome disfuncional do cristalino” tem sido mais aceito na área e engloba mudanças naturais devido ao envelhecimento do cristalino. A evolução dos dispositivos diagnósticos tem sido fator fundamental para melhor estadiamento, compreensão e caracterização dessas alterações. Mesmo com esses avanços tecnológicos e o uso de classificações subjetivas, como o Lens Opacities Classification System , um estadiamento objetivo da síndrome disfuncional do cristalino precoce ainda não foi estabelecido. A aberrometria ocular total e o índice de superfície ocular, associado à densitometria de Scheimpflug, mostraram-se instrumentais na detecção da síndrome disfuncional do cristalino precoce. Embora estadiamentos precoces de síndrome disfuncional do cristalino tenham sido propostos na literatura, nenhum foi reconhecido mundialmente até o momento. O objetivo desta revisão de literatura é avaliar o estado atual da síndrome disfuncional do cristalino a partir de uma perspectiva tecnológica, e propor um novo sistema de estadiamento para auxiliar os cirurgiões na tomada de decisões cirúrgicas.

Purpose: To report clinical outcomes and surgical technique of flanged intrascleral intraocular lens fixation with double-needle combined with either penetrating keratoplasty (PKP) or ultrathin Descemet-stripping automated endothelial keratoplasty (UT-DSAEK). Observations: Five patients underwent combined flanged intrascleral intraocular lens fixation with double-needle technique and keratoplasty. Three patients underwent triple procedure (open sky intrascleral intraocular lens fixation with double-needle and PKP) secondary to ocular trauma or a failed corneal transplant. Two patients underwent combined UT-DSAEK and intrascleral intraocular lens fixation for pseudophakic bullous keratopathy (PBK) and anterior chamber intraocular lens (AC IOL). Conclusion: Flanged intrascleral intraocular lens fixation with double-needle technique combined with PKP or UT-DSAEK was shown to be a safe and effective method of visual rehabilitation without additional intraoperative complications. Keywords: Corneal transplant, Flanged intrascleral intraocular lens fixation, Cataract surgery

Purpose To study correlations of crystalline lens anatomy and position parameters obtained using intraoperative spectral-domain (SD) optical coherence tomography (OCT) in cataract patients. Methods This retrospective study evaluated biometry data from 600 eyes of 399 cataract patients (mean age: 69±8.4 years) using intraoperative anterior segment SD-OCT during femtosecond laser-assisted cataract surgery. Lens anatomy and position parameters (anterior chamber depth [ACD] - center of the anterior cornea to the anterior lens capsule, lens thickness [LT] - distance between anterior and posterior lens capsules, and lens meridian position [LMP] - distance from center of the anterior cornea to intersection of the anterior and posterior lens) obtained with intraoperative SD-OCT, were correlated among themselves and with noncontact axial length (AL). Equatorial plane position (EPP) (distance between the plane of the lens equator and anterior capsule) was also studied. Pearson's coefficients (r-values) were determined for all correlation pairs. Results There was a moderate correlation between AL and ACD (r=0.451; P

Presbyopia affects 1.8 billion people worldwide. This reduction in distance corrected near visual acuity impacts quality of life, which prompts patients to seek treatment. Presbyopia is an early manifestation of the “crystalline lens optical dysfunction through aging,” or dysfunctional lens syndrome, and appropriate management of presbyopia is dependent on coexisting factors such as increased higher order aberrations, reduced contrast sensitivity, light scatter, and lenticular opacification. This review of published literature (PubMed and MEDLINE) is presented in narrative format and discusses medical and surgical treatments available to patients who experience presbyopia, while highlighting future therapies. Numerous strategies exist for the management of presbyopia. These strategies include pharmacological therapy, glasses and contact lenses, corneal, scleral, and lenticular procedures. This article discusses the role of several new and existing presbyopia treatments, as well as which patients are candidates for these novel therapies. Although no single treatment is ideal for all patients with presbyopia, new medical and surgical strategies increase the number of options available when addressing different stages of presbyopia and dysfunctional lens syndrome. [ J Refract Surg . 2021;37(6 Suppl):S28–S34.]

Purpose of review This review outlines ophthalmic diagnostic systems, which objectively evaluates the human visual system and its potential beyond that of Snellen acuity. Recent findings Advances in ophthalmic diagnostic systems have allowed for a deeper understanding of the optical principles of the human eye and have created the opportunity to evolve our current standards of vision assessment beyond Snellen acuity charts. Definitive comparative and validation trials will continue to be necessary in order for these advanced diagnostics to gain more widespread acceptance in the specialty, in addition to providing the guidance on the specific indications and utilities. Summary Advancements in wavefront analysis, light scatter measurements, and adaptive optics technologies can provide greater insight into an individual optical system's potential and irregularities. Modalities that test for anterior corneal surface and whole eye aberrations, light scatter and contrast sensitivity can be an excellent educational tool for our patients to help them better understand their visual dysfunction and can prove useful for medical or surgical decision-making.

Purpose Report a case of corneal melt in a patient with conjunctival intraepithelial neoplasia (CIN) treated with topical interferon (IFN) alpha-2B. Observations An 89-year-old man presented with gelatinous paralimbal lesions of the left eye extending onto the cornea with corneal neovascularization extending 5–6 clock hours. Nasally there was mild absence of the terminal vascular loops of the limbal palisades of Vogt and conjunctivalization. Diffuse punctate epithelial erosions were noted. The corneal graft displayed subepithelial and stromal edema. Anterior segment optical coherence tomography detected hyperreflectivity, sectional thickened epithelium, and abrupt transitions from normal to abnormal tissue. The patient was treated with excision of the corneal and conjunctival lesions with cryotherapy to the conjunctival borders. Excisional biopsy revealed CIN Grade 3 and carcinoma in situ of the cornea. Topical IFN alpha-2B four times daily was initiated postoperatively. Two months later, a central epithelial defect developed. The cornea progressively thinned and corneal melt ensued. The patient had several risk factors for corneal melt including neurotrophic cornea, early limbal stem cell deficiency, history of cryotherapy, keratoconjunctivitis sicca, and chronic use of glaucoma medications and steroid medications. Conclusions Interferon alpha-2B is an effective first line treatment for CIN with few side effects. It's side effects include punctate epithelial erosions, conjunctival hyperemia, and follicular conjunctivitis. We report a case of pre-existing keratoconjunctivitis sicca, early limbal stem cell deficiency, neurotrophic cornea, and newly diagnosed CIN Grade 3; it was treated with surgical excision, cryotherapy, and topical IFN alpha-2b with development of corneal melt 2 months later. Caution should be taken when using interferon alpha -2b in patients with pre-existing keratoconjunctivitis sicca, neurotrophic cornea, or limbal stem cell deficiency as it could exacerbate these conditions resulting in corneal melt.

To characterize the dysfunctional lens syndrome and review the literature on the topic. Diagnostic devices may be used to objectively evaluate the aging changes of the crystalline lens in order to better characterize the entity. Opportunities exist for future evaluation of this emerging concept. The term dysfunctional lens syndrome is gaining acceptance in our field. Objective diagnostic evaluation of aging crystalline lenses has been demonstrated to be useful in identification and characterization of the dysfunctional lens.

Presbyopia corrections traditionally have been approached with attempts to exchange power, either at the cornea or the lens planes, inducing multifocality, or altering asphericity to impact the optical system. Treatments that affect the visual axis, such as spectacle and contact lens correction, refractive surgeries, corneal onlays and inlays, and intraocular lenses are typically unable to restore true accommodation to the presbyopic eye. Their aim is instead to enhance ‘pseudoaccommodation’ by facilitating an extended depth-of-focus for which vision is sufficient. There is a true lack of technology that approaches presbyopia from a treatment based or therapy based solution, rather than a ‘vision correction’ solution that compromises other components of the optical system. Scleral surgical procedures seek to restore true accommodation combined with pseudoaccommodation and have several advantages over other more invasive options to treat presbyopia. While the theoretical justification of scleral surgical procedures remains controversial, there has nevertheless been increasing interest and evidence to support scleral surgical and therapeutic approaches to treat presbyopia. Enormous progress in scleral surgery techniques and understanding of the mechanisms of action have been achieved since the 1970s, and this remains an active area of research. In this article, we discuss the historic scleral surgical procedures, the two scleral procedures currently available, as well as an outlook of the future for the scleral surgical space for treating presbyopia.

Diffusion is an important mechanism of transport for nutrients and drugs throughout the avascular corneal stroma. The purpose of this study was to investigate the depth- and direction-dependent changes in stromal transport properties and their relationship to changes in collagen structure following ultraviolet A (UVA)-riboflavin induced corneal collagen cross-linking (CXL). After cross-linking in ex vivo porcine eyes, fluorescence recovery after photobleaching (FRAP) was performed to measure fluorescein diffusion in the nasal-temporal (NT) and anterior-posterior (AP) directions at corneal depths of 100, 200, and 300 μm. Second harmonic generation (SHG) imaging was also performed at these three corneal depths to quantify fiber alignment. For additional confirmation, an electrical conductivity method was employed to quantify ion permeability in the AP direction in corneal buttons and immunohistochemistry (IHC) was used to image collagen structure. Cross-linked corneas were compared to a control treatment that received the riboflavin solution without UVA light (SHAM). The results of FRAP revealed that fluorescein diffusivity decreased from 23.39 ± 11.60 μm2/s in the SHAM group to 19.87 ± 10.10 μm2/s in the CXL group. This change was dependent on depth and direction: the decrease was more pronounced in the 100 μm depth (P = 0.0005) and AP direction (P = 0.001) when compared to the effect in deeper locations and in the NT direction, respectively. Conductivity experiments confirmed a decrease in solute transport in the AP direction (P

Since the introduction of femtosecond laser (FS) systems for corneal flap creation in laser-assisted in-situ keratomileusis there have been numerous applications for FS laser in corneal surgery. This manuscript details the utility of FS lasers in corneal surgical procedures including refractive laser surgeries, intracorneal ring segment tunnels, presbyopic treatments, and FS-assisted keratoplasty. We also review the role of FS lasers in diagnostic procedures such as two photon excitation fluorescence and second harmonic generation.

PURPOSE: To measure retinal image quality using point spread function (PSF) analysis by double-pass retina point imaging in patients with keratoconus and to correlate visual quality with disease severity. METHODS: Patients diagnosed as having keratoconus by clinical examination, topography, and tomography and normal eyes were included in this study. A commercially available double-pass retina point imaging instrument (OQAS 108 II AcuTarget HD; Visiometrics S.L., Terrassa, Spain) was used to collect Objective Scatter Index (OSI) values in 21 keratoconic and 22 normal eyes. Eyes were also subjected to corneal topography and tomography, and staged using the Keratoconus Severity Score (KSS) and Amsler–Krumeich (AK) scales. RESULTS: The OSI was increased in keratoconic eyes (5.85 ± 0.98) versus control eyes (0.83 ± 0.12; mean ± SEM), in AK stages 1 to 4, and KSS stages 3 and 4. Receiver-operator characteristic analysis obtained an area under the curve (AUC) of 0.859 when evaluating the OSI as a unimodal diagnostic indicator for any KSS stage and 0.993 for KSS stages 3 and higher. An AUC of 0.949 was obtained in comparing eyes with lower severity topographic aberrations (KSS 1 and 2) versus mild to moderate keratoconus (KSS 3 and 4). Increasing corneal steepening patterns on tomography and topography were associated with PSF broadening and increased OSI. CONCLUSIONS: Double-pass retina point imaging is useful in correlating retinal image quality with keratoconus severity. The OSI may represent a clinically significant parameter for staging keratoconus with a unique ability to directly evaluate quality of vision in this population. [ J Refract Surg. 2016;32(11):760–765.]

Purpose of review This review outlines concepts in intraocular lens (IOL) optics and aberrations important both for current IOLs and for new IOLs in development. Recent findings Optical aberrations make a significant impact on the laboratory and clinical performance of IOLs, especially under mesopic and low-contrast conditions. Minimizing or correcting these aberrations can potentially improve visual function. Strategic management of aberrations can have clinical utility for extended depth of focus and presbyopia correction. Summary All IOLs affect ocular aberrations in some manner. It is important for clinicians and researchers to understand the implications how any residual aberrations could affect visual quality, visual side-effects, and depth of focus.

To assess changes in Ocular Response Analyzer (ORA) waveforms after UVA/riboflavin corneal collagen cross-linking (CXL) using investigator-derived and manufacturer-supplied morphometric variables in patients with keratoconus (KC) and postrefractive surgery ectasia.Prospective randomized trial of a standard epithelium-off CXL protocol.Patients with progressive KC (24 eyes of 21 patients) or postrefractive surgery ectasia (27 eyes of 23 patients) were enrolled.Replicate ORA measurements were obtained before and 3 months after CXL. Pretreatment and posttreatment waveform variables were analyzed for differences by paired Student t tests using measurements with the highest waveform scores.Corneal hysteresis, corneal resistance factor, 37-s generation manufacturer-supplied ORA variables, and 15 investigator-derived ORA variables.No variables were significantly different 3 months after CXL in the KC group, and no manufacturer-supplied variables changed significantly in the postrefractive surgery ectasia group. Four custom variables (ApplanationOnsetTime, P1P2avg, Impulse, and Pmax) increased by small but statistically significant margins after CXL in the postrefractive surgery ectasia group.Changes in a small subset of investigator-derived variables suggested an increase in corneal bending resistance after CXL. However, the magnitudes of these changes were low and not commensurate with the degree of clinical improvement or prior computational estimates of corneal stiffening in the same cohort over the same period. Available air-puff-derived measures of the corneal deformation response underestimate the biomechanical changes produced by CXL.

PURPOSE: To evaluate changes in corneal epithelial and stromal thickness after corneal collagen cross-linking (CXL) in eyes with keratoconus and postoperative corneal ectasia using spectral-domain optical coherence tomography (SD-OCT). METHODS: Anterior segment SD-OCT (RTVue-100; Optovue, Inc., Fremont, CA) was used to compare regional corneal epithelial and stromal thickness in eyes with keratoconus and ectasia before CXL and 1 and 3 months after CXL. The anterior surface of the cornea, epithelium–Bowman’s layer interface, and posterior reflective surface were used as anatomical landmarks to measure epithelial and stromal thickness, respectively. Regional thickness was assessed centrally and at 21 points 0.5 mm apart across the central 6 mm of the corneal vertex in the horizontal and vertical meridians. RESULTS: Thirty-one eyes from 30 patients were evaluated, including 17 eyes (17 patients) with keratoconus and 14 eyes (13 patients) with ectasia. Preoperatively, a highly irregular epithelial thickness profile and distribution was observed in both groups. After CXL, epithelial thickness was significantly thinner 2.5 and 2 mm below and 1.5 mm above the corneal apex (49.26 ± 5.69 μ m; range: 43 to 62 μ m), and 2.5 and 1 mm nasal and 2 mm temporal to the corneal apex (46.66 ± 4.53 μ m; range: 39 to 57 μ m) compared to preoperative values ( P < .05 for all measurements). Epithelial thickness standard deviations were significantly lower (by 3 to 6 μ m) 3 months after CXL, compared to ranges before CXL in both the vertical and horizontal meridians for keratoconus and ectasia ( P = .048). No significant differences were found between epithelial remodeling in keratoconus and corneal ectasia ( P = .98). No significant or consistent stromal changes were found for either group. CONCLUSIONS: Significant epithelial remodeling occurs after CXL in eyes with keratoconus and corneal ectasia, creating a similar, more regularized thickness profile in all meridians in the early postoperative period. This pattern of remodeling may facilitate interpretation of corneal curvature and thickness changes after CXL and may be related to visual acuity after CXL. [ J Refract Surg. 2014;30(2):122–127.]

To compare central (CCT) and peripheral corneal thickness (PCT) using Scheimpflug imaging (Pentacam), high-speed optical coherence tomography (Visante OCT), and ultrasound (US) pachymetry (Sonogage Corneo-Gage Plus) in normal, keratoconus-suspect, and post-laser in situ keratomileusis (LASIK) eyes.Department of Refractive Surgery, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA.The CCT and PCT were retrospectively measured using US pachymetry, Scheimpflug imaging, and high-speed OCT from January 2006 to March 2008. The influence of age and absolute magnitude of corneal thickness were also analyzed. Analysis was by multivariate generalized estimating equations, multivariate linear regression, and linear regression plots.One hundred sixty-three eyes were analyzed. Ultrasound pachymetry CCT measurements were consistently higher than Scheimpflug and OCT measurements (mean difference 6.5 microm +/- 1.8 [SD] and 7.5 +/- 1.4 microm, respectively) (both P.0005) in normal eyes; the difference was statistically similar and not greater with keratoconus suspicion, age, or absolute magnitude of corneal thickness (P.05). Scheimpflug measurements were significantly lower than US pachymetry in post-LASIK eyes (P.0005). There was no statistically significant difference (mean 0.9 +/- 1.4 microm) in Scheimpflug and OCT CCT measurements (P.5), although Scheimpflug measurements were significantly lower in post-LASIK eyes (P.0005). Scheimpflug PCT measurements were higher than OCT measurements, showing more agreement with increasing age (P = .017).Scheimpflug and OCT CCT measurements were reproducible but always thinner than US pachymetry in normal and keratoconus-suspect eyes. In post-LASIK eyes, OCT pachymetry maps were more accurate than Scheimpflug maps. The influence of age on PCT requires further study.

To analyze higher-order aberrations induced by different types of lenticular opacities.Federal University of São Paulo, São Paulo, Brazil.One hundred thirty-eyes of 65 patients with bilateral cataract, classified according to the Lens Opacities Classification System III (LOCS III), had complete ophthalmic examinations, corneal topography (EyeSys Technologies), and wavefront analysis (LADARWave, Alcon Laboratories). Patients with cataracts that could not be measured by a Hartmann-Shack sensor or those with coexisting ocular disease were excluded. Higher-order aberrations were compared between the nuclear, cortical, and posterior subcapsular groups for statistical significance.One hundred five eyes of 65 patients were assessed. Twenty-eight eyes (23.33%) had predominantly nuclear opacification (NO1-NO6 and C1-2), and 13 (10.83%) had mainly cortical opacification (C1-4). Sixty-four eyes (65.83%) had a mixed pattern of LOCS III classification, which hindered the establishment of a correlation between the aberrometry and cataract type. Eighteen eyes that presented with dense posterior subcapsular cataract (P4-5) and 7 eyes with cortical C5 LOCS III classification were excluded. In eyes with nuclear opacification, the mean spherical aberration with a 6.0 mm pupil was 0.45 microm +/- 0.17 (SD) and the mean coma was 0.29 +/- 0.13 microm. In eyes with predominantly cortical cataract, the mean spherical aberration was 0.12 +/- 0.10 microm and the mean coma was 0.49 +/- 0.23 microm. The cortical cataract group had statistically significantly higher coma than the other groups (P.001). The nuclear cataract group had statistically significantly higher spherical aberrations than the other groups (P.001).Different types of early lenticular opacities induced different wavefront aberration profiles. Coma predominated in the cortical cataract group, and spherical aberration predominated in the nuclear cataract group.

PURPOSE: To assess the corneal architecture and reproducibility of LASIK flap thickness created by the Amadeus II mechanical microkeratome (Ziemer Ophthalmic Systems AG) using Fourier-domain optical coherence tomography (OCT; Optovue Inc). METHODS: Anterior segment Fourier-domain OCT was used to analyze the morphology of 58 LASIK flaps from 30 patients created with the Amadeus II microkeratome 140-μm head and ML7090CLB blades (Med-Logics Inc) at 2 weeks postoperatively. Flap thickness was assessed at 10 points across the central 6 mm of the cornea (horizontal and vertical meridians). Postoperative central corneal flap thickness measured by Fourier-domain OCT was compared with intraoperative ultrasound pachymetry measurements. RESULTS: No significant difference was noted between central flap thickness measured by intraoperative pachymetry (107.2±14 μm) and postoperative OCT (111.7±11 μm; P =.07, correlation coefficient=0.86). Fourier-domain OCT measurements demonstrated functionally planar flap architecture (standard deviation [SD] of thickness across the flap=4.9 μm, SD range across the flap=2 to 9 μm) for the microkeratome flaps. CONCLUSIONS: The Amadeus II microkeratome with Med-Logics blades created thin, reproducible, functionally planar flaps as measured by Fourier-domain OCT. Central flap thickness measured by intraoperative ultrasound pachymetry was equivalent to that measured 2 weeks postoperatively by OCT.

PURPOSE: To compare visual acuity, aberrometry, and contrast sensitivity in patients who had a spherical intraocular lens (IOL) (SoFlex SE, Bausch & Lomb) implanted in one eye and an aspheric IOL (SofPort AO, Bausch & Lomb) implanted in the fellow eye during uncomplicated cataract surgery. METHODS: A prospective, multicenter, double-blind study was performed. Forty patients (80 eyes) underwent bilateral phacoemulsification with implantation of a spherical IOL in one eye and an aspheric IOL in the fellow eye. Postoperatively, visual acuity, aberrometry, and contrast sensitivity tests were performed. Statistical analyses were performed using Student t and Wilcoxon tests, and mixed effects were used for each contrast condition situation. RESULTS: Thirty-nine patients (30 women, 9 men; 78 eyes) with a mean age of 69.3±6.17 years (range: 51 to 82 years) completed the study. No statistical differences were found regarding visual acuity among eyes. Lower levels of higher order aberrations were achieved in the aspheric group. No statistical difference between groups under photopic conditions was noted. In low spatial frequencies, better performance was observed with the aspheric IOL under mesopic conditions. In high spatial frequencies, the spherical IOL produced better quality of vision. Comparing mesopic conditions with glare, visual performance was statistically better using the aspheric IOL. CONCLUSIONS: Cataract surgery results cannot be measured by means of visual acuity alone. Quality of vision must be considered, and implantation of IOLs with low levels of spherical aberrations and better contrast sensitivity are preferred. In this study, the aspheric IOL demonstrated better visual function, especially at night, when compared with spherical IOLs.

PURPOSE To evaluate the clinical outcomes of custom topographic neutralizing technique in treating highly aberrated eyes using the WaveLight ALLEGRETTO WAVE Excimer Laser. METHODS A retrospective consecutive case series of 67 eyes with decentered ablations and 48 eyes with symptomatic small optical zones after previous LASIK underwent topography-guided retreatment with the ALLEGRETTO WAVE. Sixteen keratoconus eyes underwent topographic neutralizing technique photorefractive keratectomy (PRK). The study assessed preoperative and 6-month and 1-year postoperative results regarding best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), topography, and predictability. RESULTS Sixty-seven eyes with previously decentered optical zones had an improvement of centration from 0.92 mm preoperatively to 0.30 mm postoperatively relative to pupil center (PP CONCLUSIONS Management of some highly aberrated eyes is now possible with topography-guided ablation using the WaveLight ALLEGRETTO platform and custom topographic neutralizing technique. Safety was acceptable for small optical zone and decentered ablation retreatments. The topography-guided ablation could be an alternative treatment for keratoconus patients if keratoplasty is otherwise indicated. The algorithms for custom topographic neutralizing technique need further refinement. [J Refract Surg. 2008;24:S439-S445.] ABOUT THE AUTHORS From the University of British Columbia and Pacific Laser Eye Centre, Vancouver, British Columbia, Canada (Lin, Holland); and the Department of Refractive Surgery, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (Rocha, Krueger). This study was supported by a Cleveland Clinic institutional grant from Research to Prevent Blindness Inc, New York, NY. Drs Lin, Holland, and Rocha have no financial interest in the materials presented herein. Dr Krueger receives consulting and research funds from Alcon Laboratories Inc, Ft Worth, Tex. Correspondence: David T.C. Lin, MD, FRCSC, 5/F, 1401 W Broadway, Vancouver, BC, Canada V6H 1H6. E-mail: tclin@shaw.ca

PURPOSE: This study measured the changes in visual acuity induced by individual Zernike ocular aberrations of various root-mean-square (RMS) magnitudes. METHODS: A crxl Adaptive Optics Visual Simulator (Imagine Eyes) was used to modify the wavefront aberrations in nine eyes. After measuring ocular aberrations, the device was programmed to compensate for the eye's wavefront error up to the 4th order and successively apply different individual Zernike aberrations using a 5-mm pupil. The generated aberrations included defocus, astigmatism, coma, trefoil, and spherical aberration at a level of 0.1, 0.3, and 0.9 µm. Monocular visual acuity was assessed using computer-generated Lando It-C optotypes. RESULTS: Correction of the patients' aberrations improved visual acuity by a mean of 1 line (-0.1 logMAR) compared to best sphero-cylinder correction. Aberrations of 0.1 µm RMS resulted in a limited decrease in visual acuity (mean +0.05 logMAR), whereas aberrations of 0.3 µm RMS induced significant visual acuity losses with a mean reduction of 1.5 lines (+0.15 logMAR). Larger aberrations of 0.9 µm RMS resulted in greater visual acuity losses that were more pronounced with spherical aberration (+0.64 logMAR) and defocus (+0.62 logMAR), whereas trefoil (+0.22 logMAR) was found to be better tolerated. CONCLUSIONS: The electromagnetic adaptive optics visual simulator effectively corrected and generated wavefront aberrations up to the 4th order. Custom wavefront correction significantly improved visual acuity compared to best-spectacle correction. Symmetric aberrations (eg, defocus and spherical aberration) were more detrimental to visual performance. [J Refract Surg. 2007;23:953-959.]

Purpose: To present the prospective application of the Orbscan II central 2-mm total-mean corneal power obtained by quantitative area topography in intraocular lens (IOL) calculation after refractive surgery. Methods: Calculated and achieved refraction and the difference between them were studied in 77 eyes of 61 patients with previous radial keratotomy (RK), RK and additional surgeries, myopic LASIK, myopic photo-refractive keratectomy (PRK), or hyperopic LASIK who underwent phacoemulsification without complications in 3 eye centers. All IOL calculations used the average from the central 2-mm Orbscan II total-mean power of maps centered on the pupil without the use of previous refractive data. Six IOL styles implanted within the bag were used. Results: Using the SRK-T formula, the overall calculated refraction was −0.64±0.93 diopters (D). The overall achieved spherical equivalent refraction (−0.52±0.79 D; range: −3.12 to 1.25 D; 95% confidence interval [CI]: −0.70/−0.34 D) was ±0.50 D in 53% of eyes, ±1.00 D in 78% of eyes, and ±2.00 D in 99% of eyes. The overall difference between the calculated and achieved refraction (0.12±0.93 D, P =.27; range: −2.18 to 2.62 D; 95% CI: 0.09/0.33 D) was ±0.50 D in 39% of eyes, ±1.00 D in 77% of eyes, and ±2.00 D in 96% of eyes. This difference was ±1.00 D in 77% of eyes with RK ( P =.70), 82% of eyes with myopic LASIK ( P =.34), and 90% of eyes with myopic PRK ( P =.96). In eyes with RK followed by LASIK, a trend toward undercorrection was noted ( P =.03). In eyes with hyperopic LASIK, a trend toward overcorrection was noted ( P =.005). Conclusions: In eyes with previous corneal refractive surgery, IOL power calculation can be performed with reasonable accuracy using the Orbscan II central 2-mm total-mean power. This method had better outcomes in eyes with previous RK, myopic LASIK, and myopic PRK than in eyes with hyperopic LASIK or RK with LASIK. [ J Refract Surg . 2009;25:1061–1074.]

PURPOSE: To compare visual acuity, total and high order wavefront aberrations (coma, spherical aberration, and other terms of high order aberration), and contrast sensitivity in 105 eyes implanted with 4 different types of intraocular lenses (IOLs) (1 multifocal apodized diffractive IOL and 3 monofocal IOLs). METHODS: A prospective study comparing four types of IOLs (Alcon ReSTOR [50 eyes], Alcon Acrysof MA30AC [20 eyes], Alcon Acrysof SA60AT [20 eyes], and Mediphacos Acqua IOL [15 eyes]) was carried out. All eyes were targeted for emmetropia. Complete ophtha lmological examination, including uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), contrast sensitivity (Pelli- Robson chart), and wavefront analysis, was performed 2 months postoperatively. RESULTS: All eyes in all groups had BSCVA ≥20/32 postoperatively. Mean total aberration root-meansquare (RMS) values were: 0.72?0.25 µm (ReSTOR), 0.94?0.26 µm (MA30), 0.84?0.23 µm) (SA60), and 2. 04 ?0.77 µm (Acqua). Mean higher order aberration values were: 0.35?0.15 µm (ReSTOR), 0.41 ± 0.12 µm (MA30), 0.43±0.13 µm) (SA60), and 0.85±0.50 µm) (Acqua). The Acqua IOL showed statistically significant more total and higher order aberrations when compared with the other IOLs (P CONCLUSIONS: Different types of IOLs resulted in measurably different postoperative higher order aberration patterns. The multifocal apodized diffractive IOL (ReSTOR) induced significantly less spherical aberration compared to the monofocal IOLs. Contrast sensitivity revealed better values with MA30 and SA60 IOLs when compared to ReSTOR. The integration of wavefront technology in evaluating Pseudophakie patients represents a step towards better understanding and analyzing postoperative visual quality. [J Refract Surg. 2005;21: S808-S812.]

To compare visual performance, total and high order wavefront aberrations (coma, spherical aberration, and other terms), and contrast sensitivity in 120 eyes implanted with one monofocal aspheric intraocular lens (IOL) and two spherical IOLs.Randomized prospective study.Sixty patients were randomized to receive three IOL types: Alcon AcrySofIQ (40 eyes), AcrySofNatural (40 eyes), and advanced medical optic (AMO)Sensar (40 eyes). Complete ophthalmologic examination including uncorrected visual acuity (UCVA), best-spectacle corrected visual acuity (BSCVA), corneal topography, and wavefront analysis were performed preoperatively, 30 days, and 90 days postoperatively. Pelli-Robson chart test and functional acuity contrast testing (FACT-Optec6500) were performed approximately 50 days after surgery. Statistical analyses were performed using analysis chi(2), analysis of variance (ANOVA), and multiple comparisons Tukey test.After 90 days, all eyes had postoperative BSCVAor =20/32. The AcrySofIQ IOL showed statistically significant less induction of spherical aberration (P.001) when compared with the AMOSensar and the AcrySofNatural IOLs. The AMOSensar presented significantly less spherical aberration then the AcrySofNatural (P.05). The AcrySofIQ also had lower values of total and high-order aberration (HOA) (P.05) when compared with the AMOSensar and the AcrySofNatural. The mean values of trefoil 9, coma, and HOA root mean square (RMS) decreased between one and three months (P.001, P.001, P = .023, P.001, respectively) in all groups. Mean Pelli-Robson contrast sensitivity values in photopic condition were similar between the groups. The AcrySofIQ showed better results in 3cpd spatial frequency in mesopic condition using FACT-Optec 6500 (P = .008), although there were no statistical differences in photopic and mesopic with glare conditions.