A Comprehensive Wavefront Assessment of Keratoconus Using an Integrated Scheimpflug Corneal Tomographer/Hartmann-Shack Wavefront Aberrometer.

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.

Comparison of Ocular Wavefront Aberration Measurements Obtained Using Two Hartmann-Shack Wavefront Aberrometers.

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.

Characteristics of Higher-Order Aberrations in Different Stages of Keratoconus.

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.

Safety and efficacy following 10-years of overnight orthokeratology for myopia control.

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.

Opto-mechanical design of a dispersive artificial eye.

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.

Voltage-controlled accommodating IOL system using an ion polymer metal composite actuator.

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.

Choroidal thickness in macular, nasal midperiphery, and temporal midperiphery regions and its relationship with axial length and refractive error.

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.

Ocular Accommodative and Pupillary Responses During Fixation on Augmented Reality With a Maxwellian Display.

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.

Evaluation of Aniseikonia in Patients with Successfully Treated Anisometropic Amblyopia Using Spatial Aniseikonia Test.

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.

Adaptive optics dioptric scanning ophthalmoscope with a wider field of view similar to those of normal ophthalmoscopes.

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.

Evaluation of ocular biometry in the Japanese population using a multicenter approach: Prospective observational study.

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.

Artificial accommodating intraocular lens powered by an ion polymer-metal composite actuator.

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.

Influence of refractive status and age on corneal higher-order aberration.

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-13, Z13, Z-33, Z-33 and spherical aberration (Z04) 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-33 and Z04 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.

Mechanism of action of the tetraflex accommodative intraocular lens.

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.

Factors Influencing Pseudo-Accommodation-The Difference between Subjectively Reported Range of Clear Focus and Objectively Measured Accommodation Range.

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.

Serial measurements of higher-order aberrations after blinking in patients with dry eye.

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.

Adaptive optics fundus camera to examine localized changes in the photoreceptor layer of the fovea.

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.

Characteristics of ocular higher-order aberrations in patients with pellucid marginal corneal degeneration.

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.

Effects of suppression of blinking on quality of vision in borderline cases of evaporative dry eye.

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.

Binocular open-view Shack-Hartmann wavefront sensor with consecutive measurements of near triad and spherical aberration.

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.