Accommodative State Research Articles

Night myopia is reduced in binocular vision.

Night myopia, which is a shift in refraction with light level, has been widely studied but still lacks a complete understanding. We used a new infrared open-view binocular Hartmann-Shack wave front sensor to quantify night myopia under monocular and natural binocular viewing conditions. Both eyes' accommodative response, aberrations, pupil diameter, and convergence were simultaneously measured at light levels ranging from photopic to scotopic conditions to total darkness. For monocular vision, reducing the stimulus luminance resulted in a progression of the accommodative state that tends toward the subject's dark focus or tonic accommodation and a change in convergence following the induced accommodative error. Most subjects presented a myopic shift of accommodation that was mitigated in binocular vision. The impact of spherical aberration on the focus shift was relatively small. Our results in monocular conditions support the hypothesis that night myopia has an accommodative origin as the eye progressively changes its accommodation state with decreasing luminance toward its resting state in total darkness. On the other hand, binocularity restrains night myopia, possibly by using fusional convergence as an additional accommodative cue, thus reducing the potential impact of night myopia on vision at low light levels.

Quantification of the ciliary muscle and crystalline lens interaction during accommodation with synchronous OCT imaging.

Two SD-OCT systems and a dual channel accommodation target were combined and precisely synchronized to simultaneously image the anterior segment and the ciliary muscle during dynamic accommodation. The imaging system simultaneously generates two synchronized OCT image sequences of the anterior segment and ciliary muscle with an imaging speed of 13 frames per second. The system was used to acquire OCT image sequences of a non-presbyopic and a pre-presbyopic subject accommodating in response to step changes in vergence. The image sequences were processed to extract dynamic morphological data from the crystalline lens and the ciliary muscle. The synchronization between the OCT systems allowed the precise correlation of anatomical changes occurring in the crystalline lens and ciliary muscle at identical time points during accommodation. To describe the dynamic interaction between the crystalline lens and ciliary muscle, we introduce accommodation state diagrams that display the relation between anatomical changes occurring in the accommodating crystalline lens and ciliary muscle.

Uniformity of accommodation across the visual field.

We asked the question: Does accommodation change the eye's focusing power equally over the central visual field in emmetropic and myopic adult eyes? To answer this question we modified our laboratory scanning wavefront aberrometer to rapidly measure ocular refractive state over the central 30° diameter of visual field as a function of foveal accommodative demand. On average, ocular refractive state changed uniformly over the central visual field as the eye accommodated up to 6 D. Visual field maps of accommodative error (relative to a spherical target surface of constant vergence) reveal subtle patterns of deviation on the order of ± 0.5 D that are unique to the individual and relatively invariant to changes in accommodative state. Population mean maps for accommodative error are remarkably uniform across the central visual field, indicating the retina of the hypothetical "average eye" is conjugate to a sphere of constant target vergence for all states of accommodation, even though individual eyes might deviate from the mean due to random variations. No systematic difference between emmetropic and myopic eyes was evident. Since accuracy of accommodation across the central visual field is similar to that measured in the fovea, loss of image quality due to accommodative errors, which potentially drives myopia and may affect many aspects of visual function, will be similar across the central retina.

Влияние физической нагрузки на состояние аккомодации, рефрактогенеза и регуляцию вегетативной нервной системы у детей и подростков

Влияние физической нагрузки на состояние аккомодации, рефрактогенеза и регуляцию вегетативной нервной системы у детей и подростков

Влияние физической нагрузки на состояние аккомодации, рефрактогенеза и регуляцию вегетативной нервной системы у детей и подростков

Влияние физической нагрузки на состояние аккомодации, рефрактогенеза и регуляцию вегетативной нервной системы у детей и подростков

The Value of an ARK-1s Advanced Objective Accommodometer in Measurement of Accommodation Variation in the Resting State of Accommodation

The Value of an ARK-1s Advanced Objective Accommodometer in Measurement of Accommodation Variation in the Resting State of Accommodation

Repeatability of axial length measurement under the accommodation in pseudophakic patients using ultra-long scan depth OCT

Background Accommodation is the ability of human eye to change refractive power to see near target clearly. Objective This study was to investigate the repeatability of imaging axial length (AL) under the pilocarpine-induced accommodation in pseudophakic patients using ultra-long scan depth OCT (UL-OCT). Methods A prospective study was carried out.Twenty eyes of 12 subjects who received monofocal intraocular lens (IOL) implantation were incuded in the Eye Hospital of Wenzhou Medical University from October 2014 to January 2015.The patients aged from 56 to 84 years (mean: [69.9±7.6] years). A self-built UL-OCT, with center wave length 840 nm and the axial resolution 7 μm and scan depth 37.71 mm (in the air), was employed to image the whole eye picture through the pupil in relax and accommodative states.The images were analyzed by a self-developed software to acquire the central corneal thickness (CCT), anterior chamber depth (ACD), IOL thickness, vitreous length (VL) and AL.The parameters were repeatly measured for two times, and the percentage of coefficient of repeatability (COR) was calculated.The consistency between the two measurements was evaluated by Bland-Altman agreement test. Results The average AL value was (23.241±0.882)mm, and the difference of repeated measurement values was (-0.008±0.026)mm under the relax state, without statistical difference between two measurements (P=0.283). The average AL value was (23.274±0.889)mm, and the difference of repeated measurement values was (0.002±0.028)mm under the accommodation state, without statistical difference between two measurement values (P=0.724). AL increased by (32±35)μm after the accommodation.The CORs were 0.222 and 0.240, and the COR percentages were 1.03% and 0.96% under the relax condition and accommodation condition, respectively.The Bland-Altman plots showed that the mean differences between the two repeated measurement values were close to zero in the relax condition and accommodation condition. Conclusions UL-OCT is a potential tool of obtaining AL of whole eye in pseudophakic eyes. Key words: Biomeasurement; Pseudophakic; Accommodation; Axial length; Tomography, optical coherence

Measurement of Ex Vivo Porcine Lens Shape During Simulated Accommodation, Before and After fs-Laser Treatment.

According to Helmholtz, accommodation is based on the flexibility of the crystalline lens, which decreases with age, causing presbyopia. With femtosecond (fs)-lentotomy treatment, it is possible to restore the flexibility of presbyopic lenses. The efficiency of the treatment can be systematically evaluated using the finite element method based on experimental data. The purpose of this study was to quantify the shape change of ex vivo lenses in different accommodation states according to the fs-lentotomy treatment. Five lenses with ciliary body excised from ex vivo porcine eyes (age: approximately 6 months, exact age unknown) were stretched in an accommodation device before and after laser treatment. Depending on the accommodation state, the lens shape, reconstructed from lens thickness, diameter, and anterior and posterior curvature, was measured using optical coherence tomography (OCT). The complete lens shape was parameterized and each measured parameter was compared to the results of a control group (n = 5, age: approximately 6 months, exact age unknown) without treatment. The amplitudes of the parameters thickness (+140%), diameter (+54%), and anterior radius of curvature (+57%) significantly increased after treatment (P < 0.05), and showed no significant change for the control group. By contrast, the amplitude of the posterior radius of curvature showed no change after treatment (P > 0.05). Measurement of the lens shape in different accommodation states was successful and showed significant changes after the treatment. The resulting data will be utilized as input for a finite element model to systematically evaluate the effect of fs-lentotomy treatment in future work.

Opto-mechanical artificial eye with accommodative ability.

The purpose of this study was to describe the design and characterization of a new opto-mechanical artificial eye (OMAE) with accommodative ability. The OMAE design is based on a second-pass configuration where a small source of light is used at the artificial retina plane. A lens whose focal length can be changed electronically was used to add the accommodation capability. The changes in the OMAE's aberrations with the lens focal length, which effectively changes the accommodative state of the OMAE, were measured with a commercial aberrometer. Changes in power and aberrations with room temperature were also measured. The OMAE's higher-order aberrations (HOAs) were similar to the ones of the human eye, including the rate at which fourth-order spherical aberration decreased with accommodation. The OMAE design proposed here is simple, and it can be implemented in an optical system to mimic the optics of the human eye.

The Relationship Between the Status of Unnecessary Accommodations Being Made to Unconfirmed Food Allergy Students and the Presence or Absence of a Doctor's Diagnosis.

The present study investigated the current state of unnecessary children food allergy accommodation and the medical efforts to confirm the existence of food allergies in school lunch service kitchens in Okinawa, Japan, including kitchens accommodating food allergy students by requiring medical documentation at the start and during provisions being made (Double Diagnosis), requiring medical documentation at the start only (Single Diagnosis), and with no medical documentation (Non-Diagnosis). Unnecessary accommodations are being made to unconfirmed food allergy students, wherein the more medical consultation was required, the lower the food allergy incident rate was and the more food allergens were diagnosed (Non-Diagnosis > Single Diagnosis > Double Diagnosis). This study suggests the possibility that unconfirmed food allergy students may be receiving unnecessary food allergy accommodations per school lunches, and the number of unnecessary food allergy provisions being made could be reduced by requiring medical documentation at the start and during these provisions.

Root inoculation with Pseudomonas putida KT2440 induces transcriptional and metabolic changes and systemic resistance in maize plants.

Pseudomonas putida KT2440 (KT2440) rhizobacteria colonize a wide range of plants. They have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. However, the response of maize plants to KT2440 colonization has not been investigated yet. Maize roots were inoculated with KT2440 and the local (roots) and systemic (leaves) early plant responses were investigated. The colonization behavior of KT2440 following application to maize seedlings was investigated and transcriptional analysis of stress- and defense-related genes as well as metabolite profiling of local and systemic maize tissues of KT2440-inoculated were performed. The local and systemic responses differed and more pronounced changes were observed in roots compared to leaves. Early in the interaction roots responded via jasmonic acid- and abscisic acid-dependent signaling. Interestingly, during later steps, the salicylic acid pathway was suppressed. Metabolite profiling revealed the importance of plant phospholipids in KT2440-maize interactions. An additional important maize secondary metabolite, a form of benzoxazinone, was also found to be differently abundant in roots 3 days after KT2440 inoculation. However, the transcriptional and metabolic changes observed in bacterized plants early during the interaction were minor and became even less pronounced with time, indicating an accommodation state of the plant to the presence of KT2440. Since the maize plants reacted to the presence of KT2440 in the rhizosphere, we also investigated the ability of these bacteria to trigger induced systemic resistance (ISR) against the maize anthracnose fungus Colletotrichum graminicola. The observed resistance was expressed as strongly reduced leaf necrosis and fungal growth in infected bacterized plants compared to non-bacterized controls, showing the potential of KT2440 to act as resistance inducers.

The influence of crystalline lens accommodation on post-saccadic oscillations in pupil-based eye trackers

It is well known that the crystalline lens (henceforth lens) can oscillate (or ‘wobble’) relative to the eyeball at the end of saccades. Recent research has proposed that such wobbling of the lens is a source of post-saccadic oscillations (PSOs) seen in data recorded by eye trackers that estimate gaze direction from the location of the pupil. Since the size of the lens wobbles increases with accommodative effort, one would predict a similar increase of PSO-amplitude in data recorded with a pupil based eye tracker. In four experiments, we investigated the role of lens accommodation on PSOs in a video-based eye tracker. In Experiment 1, we replicated previous results showing that PSO-amplitudes increase at near viewing distances (large vergence angles), when the lens is highly accommodated. In Experiment 2a, we manipulated the accommodative state of the lens pharmacologically using eye drops at a fixed viewing distance and found, in contrast to Experiment 1, no significant difference in PSO-amplitude related to the accommodative state of the lens. Finally, in Experiment 2b, the effect of vergence angle was investigated by comparing PSO-amplitudes at near and far while maintaining a fixed lens accommodation. Despite the pharmacologically fixed degree of accommodation, PSO-amplitudes were systematically larger in the near condition. In summary, PSOs cannot exhaustively be explained by lens wobbles. Possible confounds related to pupil size and eye-camera angle are investigated in Experiments 3 and 4, and alternative mechanisms behind PSOs are probed in the discussion.

The Development of Tourist Space in Polish Port Cities

The main aim of this article is to present the results of the analysis of tourist space in Polish port cities. Particular attention has been paid to the aspect of tourism development in four cities (Szczecin, Świnoujście, Gdańsk and Gdynia). They are cities where ports of major importance for the national economy are located. This area is also characterized by significant tourist traffic. The state of tourist accommodation and tourist traffic intensity in four Polish port cities, according to some criteria, has been examined. It is indicated that the formation of tourism development is also dependent on the creation and implementation of policy. Due to the close relationship between effective transport and tourism, aspects of city logistics should be taken into account as well as others.

Comparison of four different binocular balancing techniques

BackgroundSeveral techniques of balancing have been proposed for the equalisation of the accommodative state between the two eyes. This study was designed to compare the results of different balancing techniques.MethodsIn this study, 60 subjects participated. Refractive errors were determined using retinoscopy and results were refined with monocular subjective refraction to determine the ametropia with the most plus lens and this was used as the starting point for balancing. The monocular refractive values before the balance were the same for all balancing procedures. Four balancing techniques, three dissociated and one associated, (alternate occlusion, prism‐dissociated blur balance, prism‐dissociated red‐green balance and Humphriss immediate contrast method) were used for the final refinement of findings. Results were analysed as the interocular spherical difference (IOSD) after the completion of each balance procedure. The interocular spherical difference was defined as the right eye sphere minus the left eye sphere. Data were analysed in SPSS.17 software using the paired samples t‐test, the Pearson correlation, repeated measures ANOVA and ‘intraclass correlation coefficient’ (ICC) tests.ResultsThe lowest mean difference was related to the alternate occlusion with the prism‐dissociated blur balance techniques. The lowest 95% limits of agreement were related to the prism‐dissociated red‐green balance with the Humphriss immediate contrast methods. The highest correlation and intraclass correlation coefficient were related to the prism‐dissociated red‐green balance with the Humphriss immediate contrast methods.ConclusionsThe four balancing methods yield very similar results. The balance findings with red‐green dissociated method and the Humphriss immediate contrast technique can be considered interchangeable and the other pairs of comparisons very nearly so.

Using individual DSA titers to assess for accommodation after late humoral rejection

Management of late humoral rejection remains challenging, and DSA may persist. A case report illustrates how individual DSA titers using solid-phase-based assays may help to assess for accommodation. A male cystinosis patient received a cadaveric renal transplant at the age of 12 yr with a daclizumab, tacrolimus, MMF, and steroids-based immunosuppression. After three acute rejection episodes over the first eight months, interstitial fibrosis/tubular atrophy (IF/TA) was diagnosed on biopsy, while the immunosuppression was left unchanged with a high target exposure for both tacrolimus and MPA. One yr later, AMR type III (C4d and DSA positive) was treated with daily plasmapheresis, IVIG 100 mg/kg and pulse steroids 5 mg/kg. DSA (DR 53, DQ4, and DQ 2) were not responding until the plasma volume was increased to 2.5 plasma volumes. A second rise of creatinine confirmed worse humoral rejection; daily plasma exchange was resumed, and two doses of rituximab (375 mg/m(2)) were given. Subsequently, all DSA dropped, but only DR53 DSA remained unchanged, whereas the DQ antibodies rebounded to very strong titers. With a follow-up of over 120 days after recovery of the CD19 count, off all additional treatment and on identical immunosuppression with tacrolimus and MMF and prednisone, the patient's creatinine remained stable between 45 and 50 um while DQ DSA remain strong to very strong. We conclude that the patient is in a state of accommodation. DSA titers should be monitored when managing late humoral rejection.

Whole Eye Axial Biometry During Accommodation Using Ultra-long Scan Depth Optical Coherence Tomography

To investigate changes of whole eye axial biometry during accommodation using ultra-long scan depth optical coherence tomography (UL-OCT). Prospective, observational case series. Twenty-one adult subjects were enrolled. Using UL-OCT, the left eye of each subject was imaged with relaxed diopters (0 D) and accommodative stimuli (+6 D). Full eye biometry included central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness, vitreous length, and axial length (AL). During accommodation (+6 D), the axial biometry of the whole eye changed significantly. Compared to the rest state, ACD at the accommodative state decreased significantly from 3.128 ± 0.305mm to 2.961 ± 0.298mm (paired t test, P < .001). The lens thickness increased significantly from 3.723 ± 0.237mm to 3.963 ± 0.234mm (P < .001). The vitreous length decreased significantly from 17.129 ± 0.864mm to 17.057 ± 0.848mm (P < .001). AL was 24.519 ± 0.917mm at the rest state and increased to 24.545 ± 0.915mm with+6 D accommodation stimulus. The elongated AL of 26.1 ± 13.4μm between the rest and accommodative states was significant (P < .001). During accommodation, whole eye axial biometry changed, including a decrease in ACD and vitreous length and an increase in lens thickness and AL. UL-OCT provides an alternative method thatis suitable for full eye biometry during accommodation.

Fully Automated Biometry of In Situ Intraocular Lenses Using Long Scan Depth Spectral-Domain Optical Coherence Tomography

Spectral-domain optical coherence tomography (SD-OCT) was used to automatically measure accommodative biometric changes in the anterior segment of eyes implanted with an intraocular lens (IOL). The repeatability and reliability of the automated measurements were also evaluated. Long scan depth SD-OCT was used to image the anterior segment of eyes implanted with IOLs. A fully automated algorithm was used to detect the boundaries of the cornea and IOL and yielded the measurements. The results included anterior segment dimensions in IOL eyes and the deflection of the IOLs. Automated measurements were validated in vitro and compared with the manual results in vivo on 15 cross-sectional images from patients with IOLs. Five eyes with five different types of IOLs, respectively, were enrolled to test the repeatability of the automated measurements during accommodation. Intraocular lens central thickness and anterior and posterior curvature radii measured by long scan depth SD-OCT in vitro and in a model eye matched well with those determined by a micrometer caliper and interferometer. In vivo, there was good correlation of the biometric data determined by automated and manual segmentations (P<0.05, r-value range: 0.635-0.997). There were no significant differences for any variable between the two measurements at each accommodative state (P>0.05). Anterior chamber depth and pupil diameter showed significant changes between the nonaccommodative and 2.5-D accommodative states (P<0.05), whereas the shape of the IOLs did not change significantly (P>0.05). The long scan depth SD-OCT with the automated algorithm was verified to have a great potential in studying accommodative biometric changes of the anterior segment in eyes with IOLs and IOL deflections.

Crystalens HD Intraocular Lens Analysis Using an Adaptive Optics Visual Simulator

To compare visual and optical quality of the Crystalens HD intraocular lens (IOL) with that of a monofocal IOL. The wavefront aberration patterns of the monocular Akreos Adapt AO IOL and the single-optic accommodating Crystalens HD IOL were measured in a model eye. The Crystalens IOL was measured in its nonaccommodative state and then, after flexing the haptic to produce 1.4 mm of movement, in its accommodative state. Using an adaptive optics system, subjects' aberrations were removed and replaced with those of pseudophakes viewing with either lens. Monocular distance visual acuity (DVA) at high (100%), medium (50%), and low (10%) contrast and contrast sensitivity (CS) were measured for both IOL optics. Near VA (NVA) and CS were measured for the Crystalens HD IOL in its accommodative state. Depth of focus around the distance and near focus was also evaluated for the Crystalens HD IOL. Modulation transfer function (MTF), point spread function (PSF), and Strehl ratio were also calculated. All measures were taken for 3- and 5-mm pupils. The MTF, PSF, and Strehl ratio showed comparable values between IOLs (p > 0.05). There were no significant differences in DVA and CS between IOLs for all contrasts and pupils (p > 0.05). When spherically focused, mean DVA and NVA with the Crystalens HD IOL were ≥20/20 at 100 and 50% contrasts for both pupils. Monocular DVA, NVA, and CS were slightly better with 3- than 5-mm pupils, but without statistically significant differences. The Crystalens HD IOL showed about 0.75 and 0.50 D of depth of focus in its accommodative state and nonaccommodative state, respectively. The optical and visual quality with the nonaccommodatied Crystalens HD IOL was comparable to that of a monofocal IOL. If this lens can move 1.4 mm in the eye, it will provide high-quality optics for near vision as well.

Comprehensive investigation of subjective and objective accommodation parameters in children and teenagers with myopia

The accommodation tonus, subjective and objective parameters of accommodation were examined in 130 patients aged 6–18 years (average age 11.26 ± 0.2) with various degrees of myopia. The accommodation state was determined using subjective methods (relative accommodation reserves, amplitude of accommodation) and objective methods (binocular and monocular accommodative responses, the objective relative accommodation reserves, the habitual tonus of accommodation in the open field, tonus of accommodation rest). It was revealed, that accommodation tonus measured in the virtual, open and non-oriented spaces had different values. Myopic patients showed the highest values of the tonus accommodation rest (–0.77 ± 0.03) and the lowest values (–0.17 ± 0.02) of the habitual tonus of accommodation in the open field. A synchronic decrease of subjective and objective parameters of accommodation was revealed in children and teenagers with myopia. The subjective-measured accommodation reserves showed higher values compared to objective-measured ones. A significant difference of examined parameters between fellow eyes was revealed in anisometropic myopia: the common tonus of accommodation in virtual, as well as in real space was higher in eyes with lower myopia; in eyes with higher myopia, the tonus showed negative values in both cases. The monocular accommodative response was the same in the paired eyes, the binocular accommodative response was significantly higher in eyes with higher myopia.

Visual Discomfort and Depth-of-Field

Visual discomfort has been reported for certain visual stimuli and under particular viewing conditions, such as stereoscopic viewing. In stereoscopic viewing, visual discomfort can be caused by a conflict between accommodation and convergence cues that may specify different distances in depth. Earlier research has shown that depth-of-field, which is the distance range in depth in the scene that is perceived to be sharp, influences both the perception of egocentric distance to the focal plane, and the distance range in depth between objects in the scene. Because depth-of-field may also be in conflict with convergence and the accommodative state of the eyes, we raised the question of whether depth-of-field affects discomfort when viewing stereoscopic photographs. The first experiment assessed whether discomfort increases when depth-of-field is in conflict with coherent accommodation–convergence cues to distance in depth. The second experiment assessed whether depth-of-field influences discomfort from a pre-existing accommodation–convergence conflict. Results showed no effect of depth-of-field on visual discomfort. These results suggest therefore that depth-of-field can be used as a cue to depth without inducing discomfort in the viewer, even when cue conflicts are large.