Lens induced aniso-accommodation

Despite the evidence for consensual accommodation in response to consensual accommodative stimuli, only a few studies have investigated the binocular accommodative response to unequal (aniso) accommodative stimuli. Past studies investigating an unequal binocular accommodative response (aniso-accommodation) to aniso-accommodative stimuli have been limited by viewing conditions and measurement technique making the results, which were equivocal, difficult to interpret. This investigation addressed these limitations by the following design parameters: (1) monocular dichoptic blur cuese were provided in the binocular stimulus target to provide subjects feedback on their aniso-accommodative response and to alert the investigator of a monocular blur suppression response; (2) a training period was provided; (3) in the subjective method, each eye's stigma was positioned near the dichoptic letter viewed by the other eye. By this method, a true aniso-accommodative response could be differentiated from successive consensual responses; (4) a large range of aniso-accommodative stimuli was used, 0.50-3.0 D, presented in incremental steps of 0.5 D, allowing measurement of an average 0.75 D aniso-accommodative response for the highest (3.0 D) aniso-accommodative stimulus; (5) aniso-accommodation was measured as a function of viewing distance. For four of seven subjects, the gain of the aniso-accommodative response was significantly greater at near than at far viewing distances; (6) aniso-accommodation was confirmed objectively with measures of the response to steady state and step aniso-accommodative stimuli, using a binocular SRI Dual Purkinje Eye Tracker Optometer System. The aniso-accommodative response to step stimuli showed a very long latency period (about 11 s) and a response time of 4.5 s. A potential benefit of aniso-accommodation would be to overcome small amounts of uncorrected anisometropic refractive error. This would preserve fine stereo acuity which is impaired by unequal intraocular image contrast. Aniso-accommodation also may provide an appropriate efferent feedback signal for each eye's unique refractive error which could be used to guide developmental isometropization (attainment of equal refractive error in the two eyes.).

[1]  D. Flitcroft,et al.  Binocular interactions in accommodation control: effects of anisometropic stimuli , 1992, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[2]  K. Ciuffreda,et al.  MEASUREMENT OF ACCOMMODATIVE AMPLITUDE IN AMBLYOPIA , 1982, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[3]  E. Ball,et al.  A study of consensual accommodation. , 1952, American journal of optometry and archives of American Academy of Optometry.

[4]  P. Hendrickson,et al.  Accommodation demand and deprivation in kitten ocular development. , 1985, Investigative ophthalmology & visual science.

[5]  E B Glick,et al.  Stereoscopic perception and Snellen visual acuity. , 1974, American journal of ophthalmology.

[6]  George K. Hung,et al.  Static Behavior of Accommodation and Vergence: Computer Simulation of an Interactive Dual-Feedback System , 1980, IEEE Transactions on Biomedical Engineering.

[7]  J. Cardell,et al.  CLINICAL REFRACTION , 1959 .

[8]  W. Wilson,et al.  ACCOMMODATIVE RESPONSE IN ASYMMETRIC CONVERGENCE , 1954 .

[9]  G Westheimer,et al.  The parasympathetic pathways to internal eye muscles. , 1973, Investigative ophthalmology.

[10]  R. Jampel,et al.  The nucleus for accommodation in the midbrain of the macaque. , 1967, Investigative ophthalmology.

[11]  Miller Rj.  Temporal stability of the dark focus of accommodation. , 1978 .

[12]  C M Schor,et al.  Fatigue of accommodation and vergence modifies their mutual interactions. , 1987, Investigative ophthalmology & visual science.

[13]  N. Flax,et al.  Accommodative levels under conditions of asymmetric convergence. , 1953, American journal of optometry and archives of American Academy of Optometry.

[14]  K J Ciuffreda,et al.  INTEROCULAR EQUALITY OF TONIC ACCOMMODATION AND CONSENSUALITY OF ACCOMMODATIVE HYSTERESIS * , 1987, Ophthalmic & physiological optics.

[15]  Meredith W. Morgan,et al.  Analysis Of Clinical Data , 1944 .

[16]  H E Bedell,et al.  Identifying Amblyopia Using Associated Conditions, Acuity, and Nonacuity Features , 1985, American journal of optometry and physiological optics.

[17]  D. Goss,et al.  Prevalence of Monocular Amblyopia among Anisometropes , 1979, American journal of optometry and physiological optics.

[18]  G. V. van Alphen.  Choroidal stress and emmetropization. , 1986, Vision research.

[19]  H. D. Crane,et al.  Accurate three-dimensional eyetracker. , 1978, Applied optics.

[20]  S. McKee,et al.  Stereoscopic acuity with defocused and spatially filtered retinal images , 1980 .

[21]  G. V. Alphen.  Choroidal stress and emmetropization , 1986, Vision Research.

[22]  Kenneth N. Ogle,et al.  RELATIVE SIZES OF OCULAR IMAGES OF THE TWO EYES IN ASYMMETRIC CONVERGENCE , 1939 .

[23]  F. Schaeffel,et al.  Mathematical model of emmetropization in the chicken. , 1988, Journal of the Optical Society of America. A, Optics and image science.

[24]  M Millodot,et al.  THE EFFECT OF REFRACTIVE ERROR ON THE ACCOMMODATIVE RESPONSE GRADIENT * , 1986, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[25]  Earl L. Smith,et al.  Spectacle lenses alter eye growth and the refractive status of young monkeys , 1995, Nature Medicine.

[26]  F. Campbell,et al.  Correlation of accommodation between the two eyes. , 1960, Journal of the Optical Society of America.

[27]  H D Crane,et al.  Servo-controlled infrared optometer. , 1970, Journal of the Optical Society of America.

[28]  K J Ciuffreda,et al.  Effect of surround propinquity on the open-loop accommodative response. , 1991, Investigative ophthalmology & visual science.

[29]  Mark Rosenfield,et al.  Tonic accommodation: a review I. Basic aspects , 1993, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[30]  R. Ingram,et al.  Refraction as a means of predicting squint or amblyopia in preschool siblings of children known to have these defects. , 1979, The British journal of ophthalmology.

[31]  P. Kiely,et al.  A comparison of ocular development of the Cynomolgus monkey and man , 1987 .