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Purpose: This study aimed to investigate the choroidal thickness (ChT) distribution in adult myopic eyes, focusing on the macular, nasal midperiphery, and temporal midperiphery regions, and to explore its relationship with axial length (AL) and refractive error., Study Design: A cross-sectional, observational study., Methods: Twenty-nine eyes of 29 adult volunteers were examined. ChT was measured using high-speed swept-source optical coherence tomography covering an area of 50 degrees in three different regions: centered at macular, nasal side at 33 degrees, and temporal side at 33 degrees. Statistical analyses were performed to assess differences in ChT between regions and correlations with AL and spherical equivalent (SE)., Results: ChT was found to be thickest in the macular region, followed by the nasal and temporal midperiphery regions. Significant correlations were observed between AL/SE and ChT in the macular and temporal regions, but not in the nasal region. The temporal midperiphery showed the strongest correlation with AL and SE., Conclusion: This study revealed a nasal-temporal asymmetry in ChT distribution in myopic eyes, with the temporal midperiphery showing the thinnest ChT. The strong correlations between ChT in the temporal midperiphery and AL/SE suggest a role for the temporal choroid in axial elongation and myopia progression. These findings highlight the importance of considering peripheral ChT in understanding ocular growth and myopia management., (© 2024. Japanese Ophthalmological Society.)

Purpose: This study aimed to investigate the changes in ocular refraction and pupillary diameter during fixation on augmented reality (AR) images using a Maxwellian display., Methods: Twenty-two healthy young volunteers (average age, 20.7 ± 0.5 years) wore a Maxwellian display device in front of their right eye and fixated on an asterisk displayed on both a liquid-crystal display (real target) and a Maxwellian display (AR target) for 29 seconds (real as a baseline for 3 seconds, AR for 13 seconds, and real for 13 seconds) at distances of 5.0, 0.5, 0.33, and 0.2 meters. A binocular open-view autorefractometer was used to measure the ocular refraction and pupillary diameter of the left eye., Results: Accommodative (5.0 meters, 0.28 ± 0.29 diopter [D]; 0.5 meter, -0.12 ± 0.35 D; 0.33 meter, -0.43 ± 0.57 D; 0.2 meter, -1.20 ± 0.82 D) and pupillary (5.0 meters, 0.07 ± 0.22 mm; 0.5 meter, -0.08 ± 0.17 mm; 0.33 meter, -0.16 ± 0.20 mm; 0.2 meter, -0.25 ± 0.24 mm) responses were negative when the real target distances were farther away. The accommodative response was significantly and positively correlated with the pupillary response during fixation on the AR target (R2 = 0.187, P < 0.001)., Conclusions: Fixating on AR images using a Maxwellian display induces accommodative and pupillary responses. Accommodative responses depend on the distance between real objects. Overall, the Maxwellian display does not completely eliminate accommodation in real space.

Objectives: To characterize higher-order aberrations (HOAs) in different severities of keratoconus (KC) from the anterior and posterior corneal surfaces and whole eye using an integrated Scheimpflug corneal tomographer/Hartmann-Shack wavefront aberrometer., Methods: This study included eyes with clinical KC, topographic KC (no clinical signs), fellow eyes with very asymmetric ectasia with normal topography and no clinical signs (VAE-NT), and control eyes. Corneal and ocular wavefront aberrations were obtained using an integrated Scheimpflug tomographer/Hartmann-Shack wavefront aberrometer. The diagnostic capability of distinguishing VAE-NT from the control was also tested., Results: This study included 68 eyes with clinical KC, 44 with topographic KC, 26 with VAE-NT, and 45 controls. Clinical KC had significantly greater total HOAs and coma from the anterior and posterior corneal surfaces and whole eye than the other groups ( P <0.05). Although topographic KC had significantly greater values in all wavefront parameters than the control ( P <0.05), ocular and corneal HOAs did not differ between the VAE-NT and control groups. The coma from the anterior cornea in topographic KC was significantly greater than that in VAE-NT ( P <0.05); the coma from the posterior cornea and whole eye did not differ. Total HOAs from the anterior corneal surface exhibited the highest area under the receiver operating characteristic curve value of 0.774 (sensitivity, 73%; specificity, 78%)., Conclusion: A comprehensive wavefront assessment can be used to quantitatively evaluate corneal and ocular HOAs across various severity of KC. Total HOAs from the anterior corneal surface exhibited the potential ability in distinguishing VAE-NT from the control eyes., (Copyright © 2023 Contact Lens Association of Ophthalmologists.)

Anisometropic amblyopia is decreased visual acuity in one eye, and treatment consists of wearing complete corrective spectacles. Aniseikonia occurs with complete correction of anisometropia using spectacles. Aniseikonia has been ignored when treating pediatric anisometropic amblyopia because of the prevailing belief that anisometropic symptoms are suppressed by adaptation. However, the conventional direct comparison method for evaluating aniseikonia significantly underestimates the degree of aniseikonia. This study investigated whether the adaptation occurs due to long-term anisometropic amblyopia treatment in patients who have had successful amblyopia treatment using a spatial aniseikonia test with high accuracy and repeatability compared with the conventional direct comparison method. The amount of aniseikonia was not significantly different between the patients with successful amblyopia treatment and individuals with anisometropia without a history of amblyopia. In both groups, the aniseikonia per 1.00 D of anisometropia and the aniseikonia per 1.00 mm of aniso-axial length were comparable. The repeatability of the amount of aniseikonia using the spatial aniseikonia test did not differ significantly between the two groups, indicating a high degree of agreement. These findings suggest that aniseikonia is not adapted to amblyopia treatment and that aniseikonia increases as the difference between spherical equivalent and axial length increases.

Objectives: To assess agreement between measurements of ocular wavefront aberrations obtained using the Pentacam AXL Wave (Oculus Optikgeräte GmbH) (Aberrometer A) and KR-1W (Topcon Corp) (Aberrometer B), both of which are based on the Hartmann-Shack principle., Methods: In this prospective case-control study, ocular wavefront aberrations measurements were obtained using both aberrometers in patients with keratoconus (KC) and control participants. Ocular wavefront aberrations were measured through the natural pupil without dilation using both devices in a dark room. For both aberrometers, accommodation was inhibited by automatically adding fogging. The individual Zernike coefficients from the second to fourth order were compared between the two aberrometers for a 4-mm pupil diameter., Results: Twenty-six KC and 29 control eyes were assessed. Statistically significant correlations ( P <0.05) were observed for all Zernike coefficients, except for Z 4-2 in the control group. Bland-Altman analysis indicated good agreement between aberrometers and no statistically significant differences in the control group. However, in the KC group, patterns of proportional error were observed in vertical coma Z 3-1 (r=0.338, P =0.008), trefoil Z 4-4 (r=0.701, P =0.003), secondary astigmatism Z 4-2 (r=0.348, P =0.025), and spherical aberrations Z 40 (r=0.407, P =0.012)., Conclusions: The Zernike coefficient values measured by the two aberrometers were well correlated in the control and KC groups. However, in eyes with KC, Aberrometer B tended to present greater values in several Zernike coefficients than Aberrometer A, suggesting that wavefront measurements obtained using the two aberrometers are not interchangeable in patients with KC., (Copyright © 2022 Contact Lens Association of Ophthalmologists.)

This prospective observational study aimed to evaluate the ocular biometry of Japanese people through a multicenter approach. The uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively) in the log minimum angle of resolution (logMAR), subjective and objective spherical equivalent values (SE) of ocular refraction, anterior and posterior corneal curvature (ACC and PCC, respectively), anterior and posterior corneal asphericity (ACA and PCA, respectively), central corneal thickness (CCT), anterior chamber depth (ACD), and ocular axial length (AL) were measured in the eyes of 250 participants (mean age = 46.5 ± 18.0 years, range: 20-90 years) across five institutions in Japan. The mean UDVA, CDVA, subjective SE, objective SE, ACC, PCC, ACA, PCA, CCT, ACD, and AL were 0.68, -0.08, -2.42 D, -2.66 D, 7.77 mm, 6.33 mm, -0.31, -0.39, 0.55 mm, 2.92 mm, and 24.78 mm, respectively. Age-related changes and sex-based differences were noted in the visual acuity, refraction, corneal shape, ACD, and AL. Our results serve as basis for future studies aiming to develop refractive correction methods and various vision-related fields., Competing Interests: The authors declare no conflict of interest.

Objectives: To characterize higher-order aberrations (HOAs) in clinical and subclinical keratoconus (KC)., Methods: The study included 33, 36, and 26 patients with clinical, topographic (no clinical signs), and pretopographic (normal topography and no clinical signs) KC and 30 controls. Ocular and corneal HOAs for the 4-mm pupils were measured using a wavefront sensor and expanded up to the sixth order of Zernike polynomials. The magnitudes of trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were calculated via Zernike vector analysis and used as HOA parameters along with total HOAs. Area under the receiver operating characteristic curve (AUROC) values for each wavefront parameter for pretopographic KC were compared., Results: Control eyes and eyes with pretopographic KC had significantly lower ocular or corneal total HOAs and Zernike vector terms than those with clinical KC and topographic KC, except for ocular tetrafoil between topographic KC and pretopographic KC and spherical aberration among all groups. The AUROCs for corneal total HOAs and corneal coma for pretopographic KC and control eyes were 0.781 (100% sensitivity and 47% specificity) and 0.735 (73% sensitivity and 73% specificity), respectively., Conclusion: Corneal total HOAs and corneal coma exhibited a potential ability to discriminate pretopographic KC from normal control eyes., (Copyright © 2022 Contact Lens Association of Ophthalmologists.)

The current method of controlling the focus of an accommodating intraocular lens is based on ciliary muscle contraction and cannot be used in older patients with presbyopia. We aimed to develop a dynamically accommodating intraocular lens powered by a membrane-shaped ion polymer metal composite actuator that is thin enough to be inserted in the eye. This study addresses two key problems identified in our previous accommodating intraocular lens prototype: the lack of repeatability due to the use of swine lenses instead of artificial lenses and the occurrence of a sixth order aberration. Thus, we present a new accommodating intraocular lens design and a method to transfer energy to actuators. To accommodate lens deformation and depth of focus, we used a membrane-shaped ion polymer metal composite actuator, thin enough to be inserted in the eye, and used an artificial silicone lens. To prevent the sixth order aberration, we included a ring between the ion polymer metal composite actuator and the lens. Different voltage patterns were applied to the IPMC actuator and changes in focus were observed. We were able to obtain repeatability and prevent the sixth order aberration. The dioptric power changed to ±0.23 D when ±1.5 V was used; however, at >1.5 V, a large accommodating range occurred, in addition to astigmatic vision. Thus, we have developed a novel prototype that is completely artificial, allowing reproducible and repeatable results. Visual accommodative demands were successfully met; however, although astigmatic vision was lessened, it was not completely eradicated., Competing Interests: The authors have declared that no competing interests exist.

This study aimed to investigate the influence of refractive status and age of patients on corneal higher-order aberrations (HOAs). Four hundred and twenty-six right eyes of 426 patients were enrolled in this study. The mean and standard deviation of patient age was 47.7 ± 22.1 years. Total HOAs, spherical-like aberration, coma-like aberration, Z -1 3 , Z 1 3 , Z -3 3 , Z -3 3 and spherical aberration (Z 0 4 ) for 6-mm pupil were measured using anterior segment optical coherence tomography (AS-OCT). Subjects were classified into three groups according to the amount of spherical equivalent refractive error (SE): myopia (<-0.5 D), emmetropia (-0.5 to 0.5 D), and hyperopia (>0.5 D). The amount of corneal astigmatism was recorded. Relationship between corneal aberrations, refractive status, astigmatism, and age was analyzed. In total, total HOAs, spherical-like aberration and amount of Z -3 3 and Z 0 4 were significantly larger in the hyperopia group than in the myopia group. After adjustment for age, however, aberration components did not differ among the three refractive groups. In multiple regression analysis, age and corneal astigmatism showed significant correlation with aberrations, whereas amount of SE and refractive status did not. The current study indicated that age and amount of corneal astigmatism have significant influence on corneal HOAs, but refractive status (myopia, emmetropia, or hyperopia) is not associated with corneal HOAs., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The key determinants of the range of clear focus in pre-presbyopes and their relative contributions to the difference between subjective range of focus and objective accommodation assessments have not been previously quantified. Fifty participants (aged 33.0 ± 6.4 years) underwent simultaneous monocular subjective (visual acuity measured with an electronic test-chart) and objective (dynamic accommodation measured with an Aston open-field aberrometer) defocus curve testing for lenses between +2.00 to -10.00 DS in +0.50 DS steps in a randomized order. Pupil diameter and ocular aberrations (converted to visual metrics normalized for pupil size) at each level of blur were measured. The difference between objective range over which the power of the crystalline lens changes and the subjective range of clear focus was quantified and the results modelled using pupil size, refractive error, tolerance to blur, and ocular aberrations. The subjective range of clear focus was principally accounted for by age (46.4%) and pupil size (19.3%). The objectively assessed accommodative range was also principally accounted for by age (27.6%) and pupil size (15.4%). Over one-quarter (26.0%) of the difference between objective accommodation and subjective range of clear focus was accounted for by age (14.0%) and spherical aberration at maximum accommodation (12.0%). There was no significant change in the objective accommodative response (F = 1.426, p = 0.229) or pupil size (F = 0.799, p = 0.554) of participants for levels of defocus above their amplitude of accommodation. Pre-presbyopes benefit from an increased subjective range of clear vision beyond their objective accommodation due in part to neural factors, resulting in a measured depth-of-focus of, on average, 1.0 D.

Purpose: To compare rates of myopia progression and adverse events between orthokeratology (OK) and soft contact lens (SCL) wearers over a 10-year period in schoolchildren., Methods: Medical records of consecutive patients (≤16 years of age at baseline) who started OK for myopia correction and continued the treatment for 10 years were retrospectively reviewed. For the control group, patients who started using soft contact lenses (SCLs) for myopia correction and continued to use them for 10 years were also reviewed. Clinical data, including sex, age, manifest refraction, visual acuity, prescription lens power, and adverse events during the 10-year period, were recorded. Estimated myopia progression was calculated as the sum of 'changes in prescription lens power during 10 years' and 'residual refractive errors at the 10-year visit,' and was compared between groups. We also compared the incidence of adverse events between groups over the 10-year study period., Results: A total of 104 eyes of 53 patients who underwent OK treatment and 78 eyes of 39 patients who wore SCLs fulfilled the criteria. The estimated myopia progression over the 10-year period found in the OK and SCL groups were -1.26 ± 0.98 and -1.79 ± 1.24 days, respectively; this difference was statistically significant (p = 0.001). Additionally, lower myopia progression was found in the OK in comparison to the SCL group at all baseline ages (p = 0.003 to p = 0.049) except at 16 years old (p = 0.41). No significant difference was found in the number of adverse events found between the OK (119) and SCL (103) groups (p = 0.72)., Conclusions: The results of this study supports the long-term efficacy and safety of OK lens wear in reducing myopia progression in schoolchildren., (© 2018 The Authors Ophthalmic & Physiological Optics © 2018 The College of Optometrists.)

We present an opto-mechanical artificial eye that can be used for examining multi-wavelength ophthalmic instruments. Standard off-the-shelf lenses and a refractive-index-matching fluid were used in the creation of the artificial eye. In addition to dispersive properties, the artificial eye can be used to simulate refractive error. To analyze the artificial eye, a multi-wavelength Hartmann-Shack aberrometer was used to measure the longitudinal chromatic aberration and the possibility of inducing refractive error. Off-axis chromatic aberrations were also analyzed by imaging through the artificial eye at two discrete wavelengths. Possible extensions to the dispersive artificial eye are also discussed.

Purpose: To evaluate the influence of increases in light scattering on intraocular lens (IOL) surfaces on paraxial forward scattering using goniophotometry and Hartmann-Shack wavefront aberrometry., Methods: Surface light scattering was reproduced experimentally by acceleratedly aging 4 intraocular lenses by 0, 3, 5, and 10 years each. Light scattering from both IOL surfaces was measured using Scheimpflug photography. The paraxial forward scattering from the aged IOLs was measured using a goniophotometer with a halogen light source (wavelength: 350-850 nm) and telecentric optics, and changes in the maximum intensity and full width at 10% of maximum intensity (FW10%) were evaluated. The influences on the retina image were examined using a Hartmann-Shack aberrometer (wavelength: 840 nm). The contrast and difference from the point spread function of the central centroids were evaluated., Results: The mean surface light scattering from both IOL surfaces ranged from 30.0 to 118.3 computer compatible tape (CCT) and increased with each aging year. Evaluations using the goniophotometer and the Hartmann-Shack aberrometer showed no significant change in the paraxial forward scattering with the aging year (P > .45, Kruskal-Wallis test), and no association with the surface light scattering intensity was found (P > .75, Spearman rank correlation)., Conclusion: This experimental study using aged IOLs demonstrated that surface light scattering does not influence paraxial forward scattering.

Surgeons treat cataracts by replacing the clouded lens with an intraocular lens (IOL), but patients are required to wear reading glasses for tasks requiring near vision. We suggest a new voltage-controlled accommodating IOL made of an ionic polymer metal composite (IPMC) actuator to change focus. An in vitro experiment was conducted where an actuator was placed inside the eye and moved with applied voltage. The lens attached to the actuator was deformed by its movement to change the patient's focus. The results showed that this system can accommodate a change of approximately 0.8 diopters under an applied voltage of ± 1.3 V.

Several researchers have studied the longitudinal chromatic aberration (LCA) of eyes implanted with an intraocular lens (IOL). We investigated the LCA of eyes implanted with yellow-colored IOLs from three different manufacturers: Alcon Inc., HOYA Corp., and AMO Inc. The number of subjects was 11, 16, and 16, respectively. The LCA of eyes implanted with SN60WF and SN60AT (Alcon Inc.), and with XY-1 (HOYA Corp.), was the same as that of phakic eyes. The LCA of eyes with ZCB00V (AMO Inc.) was smaller than that of phakic eyes. The LCA of eyes implanted with Alcon's and HOYA's IOLs, but not the LCA of eyes implanted with AMO's IOLs, was positively correlated with the powers of the IOLs. We also performed simulations to verify the impacts of LCA on visual performance for 4-mm pupil diameter; the simulations were a polychromatic modulation transfer function (MTF) and a visual Strehl ratio computed on the basis of an optical transfer function (VSOTF). We concluded that the differences between the LCA of different manufacturers do not affect visual performances when some extent of higher-order aberration (HOA) exists. The smaller HOA of AMO IOLs may enhance visual performance.

Several researchers studied the longitudinal chromatic aberration (LCA) of the human eye and observed that it does not change due to age. We measured the LCA of 45 subjects' normal right eyes at three distinct wavelengths (561, 690, and 840 nm) using a Hartmann-Shack wavefront aberrometer (HSWA) while consecutively switching between three light sources for wavefront sensing. We confirmed that the LCA of the human eye does not change due to age between 22 and 57 years.

To investigate the changes in the wavefront aberrations and pupillary shape in response to electrical stimulation of the branches of the ciliary nerves in cats. Seven eyes of seven cats were studied under general anesthesia. Trains of monophasic pulses (current, 0.1 to 1.0 mA; duration, 0.5 ms/phase; frequency, 5 to 40 Hz) were applied to the lateral or medial branch of the short ciliary nerve near the posterior pole of the eye. A pair of electrodes was hooked onto one or both branch of the short ciliary nerve. The electrodes were placed about 5 mm from the scleral surface. The wavefront aberrations were recorded continuously for 2 seconds before, 8 seconds during, and for 20 seconds after the electrical stimulation. The pupillary images were simultaneously recorded during the stimulation period. Both the wavefront aberrations and the pupillary images were obtained 10 times/sec with a custom-built wavefront aberrometer. The maximum accommodative amplitude was 1.19 diopters (D) produced by electrical stimulation of the short ciliary nerves. The latency of the accommodative changes was very short, and the accommodative level gradually increased up to 4 seconds and reached a plateau. When only one branch of the ciliary nerve was stimulated, the pupil dilated asymmetrically, and the oblique astigmatism and one of the asymmetrical wavefront terms was also altered. Our results showed that the wavefront aberrations and pupillary dilations can be measured simultaneously and serially with a compact wavefront aberrometer. The asymmetric pupil dilation and asymmetric changes of the wavefront aberrations suggest that each branch of the ciliary nerve innervates specific segments of the ciliary muscle and dilator muscle of the pupil.

Purpose: Our goal was to determine the feasibility of using electrochemically treated bulk platinum electrodes with large charge injection capacity for a retinal prosthesis., Methods: Seven eyes of seven cats were studied. Small retinal areas were focally stimulated with electrochemically treated bulk electrodes (φ = 500 µm) placed in a scleral pocket. Fundus images with near-infrared (800-880 nm) light were recorded, and a 2D map of the reflectance changes elicited by the electrical currents was constructed by subtracting the images taken before stimulation from those taken after stimulation. The impedance of each electrode was measured at 1 kHz. The degree of retinal elevation by the electrode was measured by optical coherence tomography. Scleral thickness where the electrode array was inserted was measured in histologic sections., Results: The diameter of reflectance changes (full width at half maximum) was 0.42 ± 0.22 mm [mean ± standard deviation (SD)] in minor axes and 1.46 ± 0.82 mm in major axes. The threshold current decreased with a reduction in the residual scleral thickness (R (2) = 0.9215; P = 0.0002); it also decreased with an increase in retinal elevation (R (2) = 0.6259; P = 0.0111).The threshold current also decreased with an increase in electrode impedance (R (2) = 0.2554; P = 0.0147)., Conclusions: Electrochemically treated porous platinum electrodes can stimulate localized retinal areas. The threshold current necessary to stimulate the retina was influenced by residual scleral thickness and the electrode tightness of fit against the sclera.

Transcorneal electrical stimulation (TES) activates retinal neurons leading to visual sensations. How the retinal cells are activated by TES has not been definitively determined. Investigating the reflectance changes of the retina is an established technique and has been used to determine the mechanism of retinal activation. The purpose of this study was to evaluate the reflectance changes elicited by TES in cat eyes. Eight eyes of Eight cats were studied under general anesthesia. Biphasic electrical pulses were delivered transcornealy. The fundus images observed with near-infrared light (800-880 nm) were recorded every 25 ms for 26 s. To improve the signal-to-noise ratio, the images of 10 consecutive recordings were averaged. Two-dimensional topographic maps of the reflective changes were constructed by subtracting images before from those after the TES. The effects of different stimulus parameters, e.g., current intensity, pulse duration, frequency, and stimulus duration, on the reflective changes were studied. Our results showed that after TES, the reflective changes appeared on the retinal vessels and optic disc. The intensity of reflectance changes increased as the current intensity, pulse duration, and stimulation duration increased (P<0.05 for all). The maximum intensity of the reflective change was obtained when the stimulus frequency was 20 Hz. The time course of the reflectance changes was also altered by the stimulation parameters. The response started earlier and returned to the baseline later with higher current intensities, longer pulse durations, but the time of the peak of the response was not changed. These results showed that the reflective changes were due to the activation of retinal neurons by TES and might involve the vascular changes induced by an activation of the retinal neurons.

Purpose: We compared the ability of four discriminant models to detect keratoconus (KC) using Zernike coefficients of corneal aberrations., Methods: We studied 51 eyes with KC, 46 with KC suspect, 50 after laser in situ keratomileusis, and 65 normal eyes. Four statistical discriminant analyses-linear discriminant analysis, k-nearest neighbor algorithm, Mahalanobis distance method, and neural network method-were performed using Zernike coefficients of corneal aberrations obtained by a Placido-based topographer. The detection scheme was constructed using a training set of data from one half of the randomly selected study participants, and performance was evaluated by a validation set in the other half., Results: Performance of the four models was different when <12 explanatory variables were included. Performance using the 2nd- to 4th-order Zernike terms did not differ significantly among models; average accuracy was 79 %., Conclusions: Determining explanatory variables of Zernike expansion coefficients of the corneal topography in discriminant models may contribute to improving accuracy of KC detection over the discriminant model, as appropriate selection of explanatory variables gave similar results despite different discriminant models.

We examined the intrinsic signals in response to grating stimuli in order to determine whether the light-evoked intrinsic signals of the retina are due to changes in the photoreceptor activities induced by the image projected on to the retina or are due to neural activities of the inner retina. The retinas of the left eye of 12 cats under general anesthesia were examined by a functional imaging fundus camera. Near infrared light was used to monitor the reflectance changes (RCs) of the retina. Vertical grating were used to stimulate the retina at 4 Hz. The spatial frequencies of the gratings were 0.05, 0.11, 0.22, 0.43, 0.86, 1.73, and 3.46 cycles/degree (cpd). Ten images were averaged and used to analyze the RCs to obtain the peak value (PV) of a two dimensional fast Fourier transfer of the RCs. The wavefront aberrations (WA) were measured with a compact wavefront aberrometer and the spatial modulation transfer function (MTF) of the eye was calculated. The retinal reflectance image had a grating pattern. The PV of the spatial sensitivity curve was highest at low spatial frequencies (0.05 and 0.11 cpd), and the sensitivity decreased steeply with an increase in the spatial frequency. RCs were not detectable at 3.46 cpd. The MTF decreased gradually with increases in the spatial frequencies and was 0.68 at 3.46 cpd. The reflectance pattern of the retinal intrinsic signal elicited by grating stimuli of different spatial frequencies was different from that of the MTF. This suggests that the intrinsic signal represents not only the response of the photoreceptors but also other neuronal or vascular changes in the retina., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Purpose: To design and validate a new miniaturized open-field wavefront device that can be attached to an ophthalmic surgical microscope or slitlamp., Setting: Solihull Hospital and Aston University, Birmingham, United Kingdom., Design: Comparative noninterventional study., Methods: The dynamic range of the Aston aberrometer was assessed using a calibrated model eye. The validity was compared with that of a conventional desk-mounted Hartmann-Shack aberrometer (Topcon KR1W) in dilated eyes. The instruments were used in random order, with measurements repeated 5 times to assess intrasession repeatability., Results: The open-field aberrometer had a large dynamic range of at least +21.0 diopters (D) to -25.0 D. It gave similar measurements to the conventional aberrometer for mean spherical equivalent (SE) (mean difference 0.02 D ± 0.49 [95% confidence interval]; correlation r = 0.995; P<.001), astigmatic components (J0: 0.02 ± 0.15 D; r = 0.977, P<.001; J45: 0.03 ± 0.28, r = 0.666, P<.001), and higher-order aberration (HOA) root mean square (RMS) (0.02 ± 0.20 D, r = 0.620, P<.001). Intraclass correlation coefficient assessments of intrasession repeatability were excellent (SE = 1.000, P<.001; J0 = 0.998, P<.001; J45 = 0.980, P<.01; HOA RMS = 0.961, P<.001)., Conclusions: The new aberrometer gave valid, repeatable measurements of refractive error and HOAs over a large range. It can measure continuously, thus providing direct feedback on the optical status of the visual system to surgeons during intraocular lens implantation and corneal surgery., (Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate the serial changes of accommodation and spherical aberration in eyes with accommodative spasm., Methods: Four patients with accommodative spasm and ten healthy subjects were studied. The ocular refractive power (spherical equivalent) and spherical aberration were measured serially with an open-field, binocular Hartmann-Shack wavefront aberrometer. Patients and subjects wore full-correction lenses and were instructed to fixate a target set at 50 cm from the eye. The time-average of the refractive power, spherical aberration, and fluctuations of accommodation analyzed by the fast Fourier transform (FFT) of the two groups were compared., Results: The average ± standard deviation refractive power in the patients was significantly more negative than that in the healthy subject (-3.12 ± 1.06 vs. -1.49 ± 0.17 D). The integrated intensity of the FFT from 1 to 4 Hz was significantly higher in the patients than in the healthy subjects. The spherical aberration in patients was more negative than that in the healthy subjects (-0.033 ± 0.048 μm vs. 0.002 ± 0.027 μm)., Conclusions: Eyes with accommodative spasm are characterized by a lead of accommodation with greater fluctuations and negative spherical aberrations. Excessive accommodation can be measured objectively in such eyes with a binocular wavefront aberrometer without cycloplegics.

We introduce a newly developed adaptive optics dioptric scanning ophthalmoscope (AO-DSO) in which all powered optical parts were refractive lenses instead of concave or convex mirrors. By designing dioptric optics, we were able to achieve a compact instrument with a 10 deg field of view (FOV10) and 1.5 deg field of view (FOV1.5) high-resolution imaging. Although the resolution of FOV10 was sacrificed because of the variation of aberrations of the eye over the 10 deg field, our system works with AO in the case of FOV1.5 and can be used as a scanning laser ophthalmoscope with good optical slicing in the case of FOV10. To test the ability of the AO-DSO, we performed imaging on a normal subject and on a patient with occult macular dystrophy.

Purpose: To investigate the corneal higher-order aberrations (HOAs) of the anterior and posterior corneal surfaces in eyes that underwent penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and Descemet stripping automated endothelial keratoplasty (DSAEK)., Design: Retrospective, case-control study., Methods: study population: Twenty-four eyes underwent PK, 28 eyes underwent DALK, and 19 eyes underwent DSAEK; 29 normal eyes served as controls. observation procedures: The anterior and posterior corneal heights and pachymetric data were obtained with a Scheimpflug-based corneal topographer. Corneal HOAs for 4-mm pupils were calculated from the height data and were expanded with normalized Zernike polynomials. The HOAs resulting from the anterior and posterior corneal surfaces were compared among the procedures. main outcome measures: Anterior and posterior corneal HOAs (root mean square)., Results: Control eyes had significantly lower total HOAs and Zernike vector terms of the anterior and posterior surfaces than the other groups, except for spherical aberration. The mean anterior corneal surface total HOAs in the PK, DALK, DSAEK, and control groups were 1.38 ± 0.67 μm, 1.19 ± 0.57 μm, 0.61 ± 0.33 μm, and 0.21 ± 0.07 μm, respectively. The anterior corneal HOAs in the DSAEK group were significantly less than those in the PK group (P < .001) and DALK group (P < .001). The mean posterior corneal surface total HOAs were, respectively, 0.20 ± 0.09 μm, 0.24 ± 0.11 μm, 0.27 ± 0.15 μm, and 0.07 ± 0.02 μm. There were no significant differences in the posterior corneal HOAs among the treatment groups., Conclusions: Because the refractive indices between the anterior and the posterior surfaces differed greatly, eyes that undergo DSAEK have lower anterior corneal HOAs compared with PK or DALK eyes. However, the anterior and posterior corneal HOAs in DSAEK eyes still were greater than those in control eyes., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Purpose: To evaluate the quality of the image of a grating target placed in a model eye viewed through multifocal intraocular lenses (IOLs)., Design: Laboratory investigation., Methods: Refractive (NXG1 or PY60MV) or diffractive (ZM900 or SA60D3) multifocal IOLs were placed in a fluid-filled model eye with human corneal aberrations. A United States Air Force resolution target was placed on the posterior surface of the model eye. A flat contact lens or a wide-field contact lens was placed on the cornea. The contrasts of the gratings were evaluated under endoillumination and compared to those obtained through a monofocal IOL., Results: The grating images were clear when viewed through the flat contact lens and through the central far-vision zone of the NXG1 and PY60MV, although those through the near-vision zone were blurred and doubled. The images observed through the central area of the ZM900 with flat contact lens were slightly defocused but the images in the periphery were very blurred. The contrast decreased significantly in low frequencies (P<.001). The images observed through the central diffractive zone of the SA60D3 were slightly blurred, although the images in the periphery were clearer than that of the ZM900. The images were less blurred in all of the refractive and diffractive IOLs with the wide-field contact lens., Conclusion: Refractive and diffractive multifocal IOLs blur the grating target but less with the wide-angle viewing system. The peripheral multifocal optical zone may be more influential on the quality of the images with contact lens system., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Purpose: To investigate the structural changes in the photoreceptors by adaptive optics (AO) fundus imaging and Fourier-domain optical coherence tomography (FD-OCT) in eyes with occult macular dystrophy (OMD)., Design: Observational case reports., Methods: Eight eyes of four patients who were diagnosed with OMD were examined. All eyes had a complete ophthalmological examination. Multifocal electroretinograms (mfERGs) were recorded from all eyes. AO and FD-OCT images of foveal photoreceptors were obtained., Results: The best-corrected visual acuity (BCVA) of these eyes ranged from 20/20 to 20/200, and the ocular fundus was normal by conventional ocular examination in all eyes. The amplitudes of the mfERGs were decreased in the foveal area. The inner and outer segment (IS/OS) junction of the photoreceptors in the foveal area was disrupted. The IS/OS junction was intact in one eye with a BCVA of 20/20, and the outer segment layer between the IS/OS junction and retinal pigment epithelium of the FD-OCT images was identified only in the center of the fovea. The AO images showed patchy dark areas in all eyes, which indicated a disruption of the mosaic of bright spots in the fovea., Conclusion: Structural changes of photoreceptors in OMD patients were detected tangentially by FD-OCT and en face by AO.

Purpose: To compare retinal reflectance changes (RCs) elicited by transcorneal electrical stimulation (TES) to those elicited by electrical stimulation of the optic chiasma (OX)., Methods: Two eyes of two cats were studied under general anesthesia. Biphasic electrical pulses at 20 Hz were applied for 5 ms in TES, and monophasic pulses were applied for 50 μs at 100 Hz in OX stimulation. Fundus images observed with near-infrared light (800-880 nm) were recorded every 25 ms for 26 s, beginning 2 s before and ending 20 s after the electrical stimulation. To improve the signal-to-noise ratio, the images of ten consecutive recordings were averaged. Two-dimensional topographic maps of the RCs were constructed by subtracting images before the stimulation from those after the stimulation. The electrically evoked potentials (EEPs) were recorded at the OX. The effect of an intravitreal injection of tetrodotoxin (TTX) on the RCs elicited by electrical stimulation was also determined., Results: After electrical stimulation, RCs were observed at the optic disc, retinal arteries, and retinal veins. The two-dimensional maps of the RCs elicited by both TES and OX stimulation were similar. The latency of the RCs ranged from 2.0 to 4.0 s, and the peak occurred 6 to 9 s after the onset of the ES. The intensity of the RCs was correlated with the amplitude of EEP elicited by TES stimulation. The RCs disappeared after the TTX injection in both TES and OX stimulation., Conclusions: TES activates principally the retinal ganglion cells, and a change in the blood flow is initiated thereafter., (© Japanese Ophthalmological Society 2011.)

Purpose: To investigate the mechanism of action of the Tetraflex (Lenstec Kellen KH-3500) accommodative intraocular lens (IOL)., Methods: Thirteen eyes of eight patients implanted with the Tetraflex accommodating IOL for at least 2 years underwent assessment of their objective amplitude-of-accommodation by autorefraction, anterior chamber depth and pupil size with optical coherence tomography, and IOL flexure with aberrometry, each viewing a target at 0.0 to 4.00 diopters of accommodative demand., Results: Pupil size decreased by 0.62 ± 0.41 mm on increasing accommodative demand, but the Tetraflex IOL was relatively fixed in position within the eye. The ocular aberrations of the eye changed with increased accommodative demand, but not in a consistent manner among individuals. Those aberrations that appeared to be most affected were defocus, vertical primary and secondary astigmatism, vertical coma, horizontal and vertical primary and secondary trefoil, and spherical aberration., Conclusions: Some of the reported near vision benefits of the Tetraflex accommodating IOL appear to be due to changes in the optical aberrations because of the flexure of the IOL on accommodative effort rather than forward movement within the capsular bag., (Copyright 2010, SLACK Incorporated.)

Aims: To investigate the influence of 0.5% timolol gel-forming solution on ocular wavefront aberrations., Methods: In 17 normal volunteers, ocular aberration was assessed before and 5 min, 30 min, 1 h, 2 h, 3 h, 6 h and 12 h after instillation of timolol gel-forming solution. Ocular aberration was sequentially measured over a period of 10 s, and the root-mean-square (RMS) of the second-, third-, fourth- and total higher-order aberrations (HOAs) were determined. From the time course of changes in total HOAs in 10 s, the stability index (SI) and fluctuation index (FI) were calculated. The authors also investigated sequential changes in specific Zernike components such as vertical coma, horizontal coma and spherical aberration., Results: No significant changes in second-order RMS were observed (p=0.452, repeated-measures ANOVA). Topical instillation significantly increased HOAs such as third-, fourth- and total higher-order RMS (p=0.023, p=0.007 and p=0.003, respectively). Multiple comparison analysis revealed significant increases in HOAs 5 min after instillation (p=0.005 for third-, p=0.001 for fourth- and p<0.001 for total higher-order RMS, Dunnett post hoc test). FI increased significantly 5 min after instillation (p=0.013), but SI did not change significantly. With respect to sequential changes in specific components, significant changes were observed in vertical coma (p=0.004, repeated-measures ANOVA) and horizontal coma (p=0.005), but not in spherical aberration., Conclusion: Instillation of timolol gel-forming solution significantly degrades optical quality of the eye for approximately 5 min by increasing HOAs, which may cause blurred vision.

Purpose: To quantitatively evaluate the effect of overnight orthokeratology lenses intentionally left decentered after 3 months of wear and assess the influence on clinical outcomes such as ocular higher-order wavefront aberrations and contrast sensitivity function., Setting: Department of Ophthalmology, Tsukuba University Hospital, Ibaraki, Japan., Methods: This prospective study assessed refraction, visual acuity, corneal topography, wavefront aberration, and contrast sensitivity function before and 3 months after overnight orthokeratology treatment. Decentration of the treatment zone from the center of the entrance pupil was determined using computerized videokeratography (TMS-4) and data-analysis software (MatLab). The relationship between decentration and the clinical parameters was analyzed., Results: The mean age of the 23 patients (46 eyes) was 24.2 years+/-3.3 (SD) and the mean spherical equivalent refraction before treatment, -2.38+/-0.98 diopters. The mean magnitude of decentration (0.85+/-0.51 mm) was statistically significantly correlated with the amount of myopic correction (P<.05), increases in coma-like aberration (P<.01), increases in spherical-like aberration (P<.01), and reductions in contrast sensitivity function (P<.0001). Changes in contrast sensitivity function were also statistically significantly correlated with the amount of myopic correction (P<.05), changes in coma-like aberration (P<.01), and changes in spherical-like aberration (P<.01). Stepwise multiple regression analysis showed that the magnitude of decentration was the only explanatory variable related to contrast sensitivity function (P<.0001)., Conclusion: Decentered treatment of orthokeratology resulted in decreased contrast sensitivity after treatment, showing that centration of the procedure is crucial to good outcomes.

Purpose: To examine and observe the subtle retinal injuries caused by a titanium:sapphire laser with a high-resolution adaptive optics (AO) fundus camera and with Fourier-domain optical coherence tomography (FD-OCT)., Design: Observational case series., Methods: Four eyes of 2 individuals who experienced an accidental exposure to reflected light from a titanium:sapphire laser were examined. High-resolution retinal images were obtained with the AO fundus camera and by FD-OCT, and the images were compared with the findings obtained by standard clinical tests, including the Amsler test and fluorescein angiography (FA)., Results: The photoreceptor mosaic was absent in a localized area of the fovea in the images obtained by the AO fundus camera, and the photoreceptor outer segments (OS) were disrupted at the corresponding area in the FD-OCT images. The changes were detected not only in the symptomatic eye but also in the asymptomatic fellow eye in both patients. In 3 eyes, the geographic dark area in the AO image decreased during the follow-up examinations., Conclusions: Very small, localized photoreceptor disruptions can be detected in patients with minimal titanium:sapphire laser injury by cross-sectional imaging using OCT, but their extent was delineated more precisely by en face AO imaging. Because the area of the photoreceptor disruption is very small, especially in the nonsymptomatic fellow eye, it is strongly recommended that laser workers--even those without visual symptoms--be examined by FD-OCT, an AO camera, or both if they have not worn protective goggles while using a laser.

Purpose: This study was designed to investigate higher-order aberrations (HOAs) due to the posterior corneal surface in keratoconic eyes compared with normal eyes., Methods: We studied 24 normal and 28 keratoconic eyes. The anterior/posterior corneal heights and pachymetric data were obtained with a rotating Scheimpflug camera. HOAs for 6 mm pupils were calculated from the differences between the height data and the best-fit sphere, using an original program for each corneal surface. The reference axes of the measurements were aligned with the primary line of sight. The HOAs were expanded with normalized Zernike polynomials. For each pair of standard Zernike terms for trefoil, coma, tetrafoil, and secondary astigmatism, one value for the magnitude and axis was calculated by Zernike vector analysis., Results: The mean total corneal HOAs (root mean square [microm]) from the anterior/posterior surfaces were significantly (P < 0.001) higher in keratoconic (4.34/1.09, respectively) than in control eyes (0.46/0.15). The mean magnitude of each Zernike vector terms for trefoil, coma, and spherical aberration from the anterior/posterior surfaces was significantly (P < 0.001) higher in keratoconic (0.77/0.19, 3.57/0.87, -0.44/0.17) than control eyes (0.09/0.04, 0.33/0.07, 0.25/-0.07), respectively. The mean axes by vector calculation for coma due to the anterior (63.6 degrees ) and posterior surfaces (241.9 degrees ) were in opposite directions., Conclusions: Corneal HOAs on both corneal surfaces in keratoconic eyes were higher than in control eyes. Coma from the posterior surface compensated partly for that from the anterior surface. Residual irregular astigmatism in patients with keratoconus wearing rigid gas permeable contact lenses can be estimated by measuring the HOA from the posterior corneal surface.

Purpose: To evaluate the characteristics of higher-order aberrations (HOAs) in eyes with pellucid marginal corneal degeneration (PMCD)., Setting: Department of Ophthalmology, Osaka University Medical School, Osaka, Japan., Methods: Ocular HOAs were measured by aberrometry in 20 eyes with PMCD (PMCD group), 76 eyes with keratoconus (KC group), and 105 normal eyes (control group) with a 4.0 mm pupil. The magnitudes and axes of trefoil, coma, tetrafoil, and secondary astigmatism and the magnitude of spherical aberration were compared between the 3 groups using vector analysis of Zernike terms., Results: The mean axes of coma in the PMCD group (85.5 degrees) and KC group (82.5 degrees) were opposite the axis in the control group (253.7 degrees). The magnitude of coma was significantly lower in the PMCD group (0.27 microm +/- 0.19 [SD]) than in the KC group (0.70 +/- 0.37 microm) (P < .05). The mean axes of trefoil in the PMCD group (27.1 degrees) and control group (35.4 degrees) were opposite the axis in the KC group (93.8 degrees). The magnitude of spherical aberration was significantly higher in the PMCD group (0.086 +/- 0.10 microm) than in the KC group (-0.030 +/- 0.13 microm) (P < .05); the spherical aberration signs were opposite in the groups., Conclusions: Although PMCD and KC are categorized as noninflammatory corneal thinning disorders, the HOA patterns in the 2 groups differed, possibly due to differences in the positions of the corneal apex. PMCD and KC may cause distinctively different deterioration in the quality of vision.

Purpose: To examine highly localized photoreceptor disruptions in the fovea by a high-resolution adaptive optics (AO) fundus camera combined with Fourier-domain optical coherence tomography (FD OCT)., Design: Observational case series., Participants: Three eyes of 3 patients who showed dark foveal spots by slit-lamp biomicroscopy., Methods: Three patients who reported metamorphopsia but showed no changes in the retina in conventional fundus photographs were examined. High-resolution retinal images were obtained with the AO fundus camera and by FD OCT. The images were compared with the findings obtained by standard clinical tests, including Amsler charts and fluorescein angiography (FA)., Main Outcome Measures: Quantitative measurements of the area of photoreceptor disruption., Results: Slit-lamp biomicroscopy revealed an irregularly shaped dark spot in the fovea centralis but no changes in FA in the 3 cases. The photoreceptor mosaic was absent in a highly localized area of the fovea in the images obtained by the AO fundus camera, and the photoreceptor outer segment was absent or disturbed at the corresponding area by FD OCT in all 3 cases. The horizontal and vertical sizes of the area of disturbance of the photoreceptor mosaic in the AO images in the 3 eyes were 400x200 microm, 300x120 microm, and 300x200 microm. These sizes were comparable to the photoreceptor outer segment disturbances in the OCT images which were 330x150 microm, 280x100 microm, 200x150 microm, respectively., Conclusions: Localized OS disturbances were able to be detected in eyes with a dark foveal spot by AO fundus camera 2-dimensionally and by FD OCT axially. The good correspondence of the sizes of the area of photoreceptor disturbances obtained by AO images to those by FD OCT images indicate that the AO images can be used to evaluate and follow the 2-dimensional area of focal changes of the photoreceptors in the fovea quantitatively.

Purpose: To report on images of the human photoreceptor mosaic acquired in vivo with a newly developed, compact adaptive optics (AO) fundus camera., Methods: The photoreceptors of two normal subjects and a patient with macular dystrophy were examined by using an AO fundus camera equipped with a liquid crystal phase modulator. In the eye with macular dystrophy, the fixation point in the AO images was identified using scanning laser ophthalmoscope (SLO) microperimetric image superimposed on a color fundus photograph., Results: Photoreceptor cells were detected as bright dots approximately 4 microm in diameter in normal subjects. In the eye with macular dystrophy, the fixation point was located within the bull's eye lesion and uniform small whitish spots with irregular patchiness were observed in the AO images of this area. The distance between the small spots was 3-4 microm. In other parts of the bull's eye retinal lesion, the whitish spots were larger and of different sizes., Conclusions: The photoreceptor mosaic could be identified in photographs of eyes of normal subjects and an eye with macular dystrophy in vivo by an AO fundus camera. In the eye with macular dystrophy, a relatively uniform photoreceptor mosaic was observed around the fixation point, whereas presumed debris of photoreceptor degradation was observed in the other bull's eye retinal lesion.

We have developed a binocular open-view Shack-Hartmann wavefront sensor for measuring time variation of binocular accommodation, vergence, pupil sizes (i.e., the binocular near triad), and monochromatic aberrations. The device measures these values16 times per second for up to 1 min. Our purpose is to introduce the new instrument. We have confirmed the accuracy of the device. Refractions for a 4 mm pupil were accurate across the range of measurements of model eyes and normal human eyes. We measured binocular dynamics of accommodation, vergence, and spherical aberrations.

Purpose: To study the effects of suppression of blinking on quality of vision in borderline cases of evaporative dry eye., Methods: Ocular higher-order aberrations (HOAs) were measured sequentially for 30 seconds in 10 eyes with a short tear film breakup time (TBUT; 3.0 +/- 0.6 seconds) without ocular surface staining or tear deficiency. During measurements, the subjects suppressed blinking to every 10 seconds, which is more than double the TBUT. The aberration data were analyzed for comalike and spherical-like aberrations and total HOAs to the sixth-order Zernike polynomials., Results: Sequential changes in total HOAs in subjects with a short TBUT showed a sawtooth pattern with a marked upward curve that increased after blinking. From 5 to 9 seconds after blinking, the total HOAs were significantly higher than immediately after blinking (P < 0.001)., Conclusions: Serial HOA measurements showed that optical quality might deteriorate in subjects with a short TBUT by suppressed blinking, such as when gazing at a video display terminal, even with sufficient tear volume.

Purpose: To investigate whether the polymer composition of disposable soft contact lenses affects sequential changes in higher-order aberrations (HOAs)., Methods: Fifteen subjects who wore disposable soft contact lenses with dryness-related symptoms and 15 non-contact lens wearers were enrolled in this study. Ocular HOAs were measured for 60 seconds in each subject wearing a disposable etafilcon A lens (conventional lens) or a disposable etafilcon A lens with polyvinyl pyrrolidone (PVP) (lens with PVP) after 1 hour of contact lens wear. During the measurement, subjects were forced to blink every 10 seconds. The aberration data were analyzed in the central 4-mm diameter up to the sixth-order Zernike polynomials. Total HOAs, the fluctuation index (FI), and the stability index (SI) of the total HOAs over time were compared between the two groups. The subjective ocular dryness also was scored., Results: In symptomatic wearers of disposable soft contact lenses, the total HOAs, the FI, and the SI with the lens with PVP were significantly (P=0.013, P=0.014, P=0.019, respectively) lower than with the conventional lens, whereas a significant (P=0.018) difference between the two lenses was observed only in the FI in non-contact lens wearers. Subjective ocular dryness with the lens with PVP significantly decreased compared with the conventional lens in both groups., Conclusions: Sequential measurement of HOAs may be a useful objective method to evaluate the effect of internal lubricating agents of disposable soft contact lenses on optical quality.

Purpose: To study the sequential postblink changes in ocular higher-order aberrations (HOAs) in patients with dry eye., Methods: A wavefront sensor was used to measure HOAs sequentially for 30 seconds in 20 eyes of 20 patients with dry eye. The 20 eyes were classified into two groups, with or without superficial punctate keratopathy (SPK) in the central cornea. During the measurement, subjects were required to blink every 10 seconds. The aberration data were analyzed in the central 4-mm diameter for coma-like, spherical-like, and total HOAs up to sixth-order Zernike polynomials. Total HOAs, as well as fluctuation index (FI) and stability index (SI) of the total HOAs over time were compared between the two groups. The sequential changes in coma-like aberration, spherical-like aberration, and total HOAs were also investigated., Results: The total ocular HOAs were significantly (P = 0.001) greater in dry eyes with central SPK than in dry eyes without central SPK. The sequential pattern of the total ocular HOAs had higher initial and consistently higher values in dry eyes with central SPK, whereas that of dry eyes without central SPK showed consistently lower total HOAs that were similar to the pattern of normal eyes., Conclusions: Increased HOAs in dry eye at least partially result from SPK above the optical zone. The low tear volume in dry eye may not cause sequential increases in HOAs after blinking. Sequential measurement of HOAs may be useful for evaluating the sequential changes in optical quality in patients with dry eye.

Purpose: To determine the cone spacing in normal and myopic eyes from the images obtained by an adaptive optics (AO) fundus camera., Methods: Nineteen eyes of 19 healthy volunteers with a mean +/- SD spherical equivalent refractive error of -3.7 +/- 3.3 diopters (D) (range, -0.3 to -11.1 D) and a mean axial length of 25.4 +/- 1.61 mm (range, 23.4-28.0 mm) were investigated in a prospective cross-sectional study. An AO fundus camera equipped with a liquid crystal phase modulator was used to obtain the images of the photoreceptor mosaic. The spacing between the cones was calculated manually at a retinal locus 2 degrees temporal from the center of the fovea. The magnification of the image was calculated by the axial length measured with an IOL Master., Results: The axial length was correlated with the refractive error (Pearson, r = -0.869; P < 0.001). The average cone spacing in the moderate- to high-myopia group (-6.5 +/- 2.3 D, n = 9) was 4.71 +/- 0.44 microm, which was significantly greater (P = 0.002) than the 3.90 +/- 0.47 microm in the normal and low-myopia groups (-1.1 +/- 0.9 D, n = 10). The cone spacing was significantly correlated with the axial length (r = 0.77, P < 0.001)., Conclusions: The AO fundus camera is capable of acquiring images of the photoreceptors in normal and myopic eyes. The greater spacing between cones in the myopia group is consistent with histological findings. These results suggest that retinal expansion should be considered in addition to Knapp's law when aniseikonia is evaluated in axial myopia., ((c) Japanese Ophthalmological Society 2007)

Purpose: To determine whether reflectance changes of the retina after electrical suprachoroidal-transretinal stimulation (STS) can be detected with a newly developed optical imaging fundus camera., Methods: Ten eyes of 10 cats were studied. A small retinal area was focally stimulated with electric currents passing between an active electrode placed in the fenestrated sclera and a reference electrode in the vitreous. Biphasic pulses were applied for 4 seconds with a current up to 500 muA. Images of the fundus illuminated with near-infrared (800-880 nm) light were obtained every 20 msec for 26 seconds between 2 seconds before and 20 seconds after the STS. Twenty images of 20 consecutive experiments were averaged. A two-dimensional map of the reflectance changes was constructed by subtracting the images before the stimulation from those after the stimulation. STS-evoked potentials (EPs) were recorded from the optic chiasma., Results: Approximately 0.5 second after the onset of STS, reflectance changes were observed around the retinal locus, where the stimulating electrodes were positioned. The intensity of the reflectance changes was correlated with the intensity of the stimulus current. The area of the reflectance change increased as the current intensity increased and was correlated with the amplitude of the EPs (R(2) = 0.82)., Conclusions: Reflectance changes after STS were localized to the area around the electrode. The strong correlation between the area of the reflectance changes and the amplitude of the EPs suggested that the reflectance changes reflected the activity of retinal neurons elicited by electrical stimulation.

Purpose: To measure the magnitude and orientation of the Zernike terms in keratoconic eyes, with and without rigid gas-permeable (RGP) contact lenses., Methods: A total of 76 eyes with keratoconus, 58 eyes with keratoconus suspect, and 105 normal eyes were studied. To determine the effect of RGP lenses, 19 eyes with keratoconus, 9 eyes with keratoconus suspect, and 17 normal eyes, with and without an RGP lenses, were compared. Ocular higher-order aberrations (HOAs) were measured with a wavefront sensor for a 4-mm-diameter pupil, and the magnitudes, axes of trefoil, and coma were calculated by vector analysis., Results: Zernike vector analysis showed prominent vertical coma with an inferior slow pattern, with mean axes of 82.5 degrees or 91.0 degrees in the patients with keratoconus or keratoconus suspect, respectively. The mean axes of trefoil in patients with keratoconus (93.8 degrees ) and keratoconus suspect (100.6 degrees ) differed from that in normal subjects (35.4 degrees ), indicating that keratoconus has a reverse trefoil pattern from that of normal eyes. Although the total HOAs were significantly (keratoconus and keratoconus suspect, P < 0.001 and P = 0.012, respectively) reduced with an RGP lens, the patterns of the axes of coma and trefoil were reversed with the lens., Conclusions: In addition to the larger amount of trefoil, coma, tetrafoil, and secondary astigmatism, keratoconic eyes tend to have a reverse coma pattern and reverse trefoil aberrations compared with normal eyes. Although RGP lenses correct the irregular astigmatism, smaller comet-like retinal images in the opposite direction remain due to residual vertical coma.

Purpose: Wavefront aberrations (WFAs) of the eye vary with time because of the tear film dynamics. We investigated, using a simulation method, the variation of optical quality with time-varying wavefront measurements of 13 eyes with different refractions., Methods: WFAs of 13 normal eyes of 13 subjects were measured every second for 10 s. First, we simulated WFAs with conventional corneal laser refractive surgery by subtracting the second-order aberrations of the least aberrated measurement from measured consecutive WFAs. Second, we simulated customized refractive surgery by subtracting the second- to sixth-order aberrations of the least aberrated measurement from measured consecutive WFAs. We calculated Strehl ratios and retinal images from these corrected consecutive WFAs., Results: In one eye, the root mean square (RMS) values of WFAs with a second-order correction were sometimes smaller than those of WFAs with a second- to sixth-order correction, when these were compared at the same time point after a blink. However, in the other 12 eyes, the RMS values with second- to sixth-order corrections were smaller than those with only a second-order correction. In eight eyes, the Strehl ratios with second- to sixth-order corrections were larger than those with second-order corrections. In the remaining five eyes, Strehl ratios with second- to sixth-order corrections were sometimes smaller than those with second-order corrections., Conclusions: In a simulation, the correction of time-invariant higher order aberrations usually reduced RMS values, but it did not always result in higher Strehl ratios than those obtained with only second-order corrections.

Purpose: To investigate sequential changes in the optical quality of normal eyes associated with blinking., Methods: Ocular higher-order aberrations (HOAs) were measured sequentially by using a wavefront sensor for 30 seconds in 20 eyes of 20 normal subjects. During the measurement, subjects were forced to blink every 10 seconds. The obtained aberration data were analyzed in the central 4-mm diameter for coma-like, spherical-like, and total HOAs up to the sixth-order Zernike polynomials., Results: The serial changes in the HOAs with blinking were classified into four groups by pattern: stable (25%), small-fluctuation (45%), sawtooth (20%), and others (10%). In the subjects with the sawtooth pattern, the total HOAs increased significantly (P < 0.001, one-way repeated-measures ANOVA) with time between blinks. Increased total HOAs and coma-like aberrations in the subjects with the sawtooth pattern suggested that the inferosuperior asymmetric change in tear film thickness is responsible., Conclusions: Dynamic changes in HOAs after blinking showed variations even in clinically normal subjects. Serial measurements of HOAs may be useful in evaluating the dynamic changes in tear film and the effects on the quality of vision after blinking.

Purpose: A clinical investigation of novel methods for evaluating light scattering using a Hartmann-Shack aberrometer., Methods: Aberrometry was performed on normal eyes (n=7; patient age, 26.7+/-2.5 years, mean+/-SD), eyes with keratoconus (n=22; patient age, 26.1+/-8.1 years), and eyes with cataract (n=17; patient age, 56.5+/-16.9 years) using a Hartmann-Shack wavefront aberrometer. We introduced two methods: (1) a contrast method, in which we calculated the inverse of contrast of the local images around 12 spots in a Hartmann-Shack image, and (2) a difference of point spread function (PSF) method, in which we analyzed the difference between the width of the PSF computed with aberration information and the width of the measured PSF, which contains both aberration and light scattering information., Results: The inverse contrast in cataractous eyes (5.04+/-3.06 inverse contrast units) was significantly larger than that in normal eyes (1.57+/-0.56) or keratoconic eyes (1.83+/-0.79). The difference of PSF in cataractous eyes (81.8+/-65.2 microm) was also significantly larger than that in normal eyes (9.3+/-4.3 microm) or keratoconic eyes (30.0+/-20.1 microm). The inverse contrast and the difference in the PSF were highly correlated (r=0.89, P<0.0001)., Conclusions: The two methods introduced here successfully distinguished cataractous eyes from normal and keratoconic eyes. After the results were analyzed by a discriminant analysis, the separation of the three categories proved to be excellent., (Copyright (c) Japanese Ophthalmological Society 2006.)

Purpose: To determine the effects of the reference axes used during the measurements of ocular and corneal higher-order aberrations (HOAs) in patients before and after laser in situ keratomileusis (LASIK)., Methods: Wavefront sensing and corneal topography were determined for 29 eyes of 15 patients before and after LASIK. Ocular and corneal HOAs were calculated for 4-mm- and 6-mm-diameter pupils with the instrument aligned with the line of sight (LOS) or with the vertex normal (VN)., Results: For ocular HOAs after surgery, the spherical-like aberration was significantly larger when the VN axis rather than the LOS axis was used for pupils of both diameters. For corneal HOAs before surgery, in addition to the larger spherical-like aberration for VN, coma-like aberrations were significantly larger with LOS than with VN for both pupil diameters. For corneal HOAs after surgery, the spherical-like aberrations and total HOAs for 4-mm-diameter pupils with VN were significantly larger than those with LOS., Conclusions: The HOAs were significantly different depending on the axes used and should be described on the basis of a common axis. These results suggest that the anterior surface of the normal or post-LASIK cornea is more rotationally symmetrical along the VN than along the LOS., (Copyright (c) Japanese Ophthalmological Society 2006.)

Purpose: To determine whether higher-order aberrations can explain the monocular diplopia reported by a patient., Design: Observational case report., Methods: A patient complaining of monocular diplopia was examined with the Hartmann-Shack aberrometer to determine if the higher-order wavefront aberrations could account for the diplopia. The patient had a mild cortical cataract, and measurements were made before and after lensectomy. In addition, the retinal image was simulated using Zernike polynomials., Results: Spherical aberration (0.20 microm for 4-mm pupil) and secondary astigmatism (-0.12 microm) were increased in the eye. The simulated retinal image had a double configuration that was approximately the same as the subjective image reported by the patient. After cataract surgery, the diplopia disappeared, and the spherical aberrations and secondary astigmatism were considerably decreased., Conclusions: The monocular diplopia probably stemmed from the combined effects of spherical aberration and secondary astigmatism caused by the cortical cataract.

We report a paradoxical increase in visual impairment after punctal plug placement despite improvement in corneal epithelial damage caused by mild dry eye. Ocular higher-order aberrations (HOAs) were measured sequentially with a wavefront sensor before and after punctal plug insertion in a patient with mild dry eye. Although postblink HOAs tend to increase in normal subjects or patients with dry eye, after treatment there was a maximum spike in HOAs for a few seconds that decreased gradually. Excessive retention of tear film by punctal occlusion may cause inferosuperior asymmetrical distribution in precorneal tear-film thickness, possibly leading to slower wavefront on the inferior cornea and increased coma-like aberrations. Increased visual impairment might occur paradoxically despite improvement in the corneal epithelial damage caused by dry eye.