Mechanical components of human eye movements

Robinson, David A.; O'Meara, David M.; Scott, Alan B.; Collins, Carter C.

doi:10.1152/jappl.1969.26.5.548

Cited by 149 publications

(83 citation statements)

References 16 publications

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“…Most of the available experiments are limited to the cases of the dead animal eyes see for example the work by Schoemaker et al 2006 . Only a few of the experiments are done on live human eye such as Robinson et al 1969 . The dead organ characteristics vary based on how they are preserved in laboratory till the experiment is done see Schoemaker et al 2006 .…”

Section: Materials Properties and Mechanical Characteristicsmentioning

confidence: 99%

“…Many of these features are not studied till now. Meanwhile reliable available experimental data about the eye parts mechanical characteristics are limited details can be found in works by Schoemaker et al 2006, Robinson et al 1969and Yoo et al 2011 . We are intended to obtain some information which are not convenient through the conventional experiments through our model.…”

Section: Introductionmentioning

confidence: 99%

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Simulation of Active Eye Motion Using Finite Element Modelling

Karami

Eghtesad

2018

Lat. Am. j. solids struct.

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Dynamic simulation of human eye movements can significantly improve our understanding about the visuomotor system and also may be used for clinical applications. In this study we have developed a 3D finite element model of the eye orbit. The major novel issues which are considered in this work are using dynamic finite element method for properly mass distribution modelling during simulation and active motion simulation by employing muscle activation parameter. In this modelling, extraocular muscles are modelled using a continuum constitutive hyper-elastic energy function. Simulation results of force duction and active motion are presented and compared with the experimental results to verify the accuracy and reliability of the proposed modelling. Then, orbital fat deformation during eye motion is studied through various simulations and compared with experimental results. Finally, the proposed eye model and available experimental data are exploited to investigate more details about eye suspension deformation and extraocular muscles characteristics. Keywords eye orbit, finite element, active motion, hyper-elastic muscle model.

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Section: Materials Properties and Mechanical Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulation of Active Eye Motion Using Finite Element Modelling

Karami

Eghtesad

2018

Lat. Am. j. solids struct.

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“…With regard to muscle stiffness, Robinson [34], Collins [17] and Simonsz [18] found that the relation between length and force of a contracting eye muscle is approximately linear, whether it contracts moderately or strongly. Force development by the muscles is therefore only dependent on elongation and activation in the static gaze.…”

Section: Appendix Amentioning

confidence: 99%

Human error in strabismus surgery: quantification with a sensitivity analysis

Schutte

Polling

Helm

et al. 2008

Graefes Arch Clin Exp Ophthalmol

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Background Reoperations are frequently necessary in strabismus surgery. The goal of this study was to analyze human-error related factors that introduce variability in the results of strabismus surgery in a systematic fashion. Methods We identified the primary factors that influence the outcome of strabismus surgery. For each of the human-error related factors we quantified variation with clinical assessments: measurement of the angle of strabismus, surgical strategy and surgical accuracy. Firstly, six patients were examined by six orthoptists, and accuracy of prism cover tests was assessed. Secondly, a questionnaire with sample cases (10°, 15°and 20°of infantile esotropia) was put to orthoptists, to determine variation in current surgical strategy. Finally, photographs made during surgery were analyzed to assess surgical accuracy. The influence of human-error related factors was related to the influence of inter-patient differences with a mechanical model. The relative contribution of all factors was assessed with a sensitivity analysis, and results were compared to clinical studies. Results The surgical trajectory of strabismus surgery could be modeled mathematically. Measurement of angle of strabismus, surgical technique, anatomy and physiology were considered. Variations in the human-error related factors were: (1) the latent angle at distant fixation was measured with a 90% confidence interval of 5°, and comprised 20% of the total variance of the postoperative angle, (2) orthoptists decided for bilateral recessions of, respectively, 7.3±1.7 mm (total amount of two recessions), 9.1±1.2 mm and 10.3±1.3 mm, which comprised 15% of the total variance, and (3) surgical accuracy was estimated at ±0.5 mm, which comprised 20% of the total variance. Conclusion The human error in strabismus surgery could be quantified with a sensitivity analysis. Approximately half of the reoperations in strabismus surgery are caused by inaccuracy in the measurement of the angle of strabismus, variability in surgical strategy and imprecise surgery.

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“…The contractile force of the extraocular muscles (EOMs) is positively correlated to the EOM length. 6,7 Proliferative retrobulbar tissue pushes the eyeball forward and elongates the four rectus muscles, causing them to pull the eyeball more strongly posterior. Therefore, the direction of the final vector on the eyeball results in a compressive force parallel to the visual axis, increasing the amplitude of the vector.…”

Section: Introductionmentioning

confidence: 99%

Biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy

Kim

Chun

Cho

et al. 2015

Eye

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Purpose To determine the biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy (TAO). Methods Retrospective, observational study (between October 2012 and September 2014) was performed. Patients with TAO undergoing orbital decompression for stable proptosis received ophthalmic examinations, including Hertel exophthalmometry, A-scan biometry, autorefraction measures, corneal topography, and wavefront aberration measures, before orbital decompression and again 2 months after surgery. Results Included in the study were 43 eyes from 23 patients. The mean exophthalmometric value decreased by 4.1 mm 2 months after orbital decompression (Po0.001). On average, axial length (AL) increased significantly by 0.08 mm (Po0.001); specifically, 37 (86%) of the 43 eyes had increased AL. Whereas anterior chamber depth and lens thickness showed no significant changes (P = 0.086 and P = 0.905, respectively), the mean spherical refraction and spherical equivalent (SE) decreased by 0.35 and 0.48 D, respectively (P = 0.008 and Po0.001, respectively). However, cylindrical refraction and axis showed no significant changes (P = 0.057 and P = 0.218, respectively). The changes in AL and SE were significantly correlated (R = − 0.411, P = 0.009). Notably, there were no changes in corneal topography or wavefront aberration after orbital decompression. Conclusions TAO patients who underwent orbital decompression showed myopic refractive change via increase in AL. Possible refractive changes should be considered in cases of TAO complaining of decreased visual acuity after orbital decompression.

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Mechanical components of human eye movements

Cited by 149 publications

References 16 publications

Simulation of Active Eye Motion Using Finite Element Modelling

Simulation of Active Eye Motion Using Finite Element Modelling

Human error in strabismus surgery: quantification with a sensitivity analysis

Biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy

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