PubMed · 12982884
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G H JONKERS. 1952-06-07. [An improved accomodometer].. https://pubmed.ncbi.nlm.nih.gov/12982884/
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PURPOSE: To assess and correct images of the eye for movements that can confound the evaluation of the presence, direction, and magnitude of intraocular movement of the crystalline lens equator during centrally induced ciliary muscle contraction (accommodation). METHOD: Ultrasound biomicroscopic (UBM) video images of a cynomologus monkey crystalline lens were obtained from an independent source. The images, prior to, during, and following electrical stimulation of the Edinger-Westphal (EW) nucleus were compared for evidence of movement of the crystalline lens equator. Extraocular eye movements were assessed by use of objective computer imaging analysis techniques. RESULTS: Extraocular eye movements were identified and reduced by using objective computer imaging analysis techniques to register and realign the corneal images. Highly significant corrections are required to effect corneal realignment. Analysis of paired and registered images from this data source indicates that any movements of the primate lens equator are not detectable when maximum accommodation was induced by EW stimulation. CONCLUSION: The displacement of the edge of the primate crystalline lens equator during electrically induced contraction of the ciliary muscle is a small displacement phenomenon, only analysable after confounding extraocular movements are removed from the compared images.
PURPOSE: To compare the amplitude of apparent accommodation in eyes with monofocal intraocular lenses with that of normal accommodation in the phakic fellow eyes in various age groups. PATIENTS AND METHODS: In all, 130 eyes of 130 patients scheduled to undergo cataract surgery, and 130 fellow eyes that had little cataract and good visual acuity of 20/33 or better were studied. The following groups were studied: in their 40s and younger (n = 20) or in their 50s (n = 30), 60s (n = 30), 70s (n = 30), and 80s (n = 20). Using an accommodometer (Kowa HS-9E), the accommodative amplitude was measured at 1 month after surgery. RESULTS: In the patients in their 40s and younger or in their 50s, the amplitude of apparent accommodation was significantly less than that of normal accommodation; no significant difference was observed in the patients in their 60s, 70s, or 80s. The incidence of patients in whom the amplitude of apparent accommodation was more than that of normal accommodation was greater in the patients in their 60s, 70s, and 80s than in the patients in their 40s and younger and in their 50s. CONCLUSION: The amplitude of apparent accommodation is virtually equivalent to that of normal accommodation in patients older than 60 years of age.
BACKGROUND: Eye preference refers to an asymmetric use of the two eyes, but it does not imply a unitary asymmetry between the eyes. Many different methods are used to assess eye preference, including eyedness questionnaires and sighting tasks that require binocular and monocular alignment of a target through a hole in the middle of a card or funnel. The results of these coarse accounts of eye preference are useful as a first screening, but do not allow for graded quantification of the manifested asymmetry in binocular vision. Moreover, they often concern only a rather selective range of binocular functions. The aim of the present study was to further differentiate eye preference within the context of other binocular functions as measured in standard optometric tests, and to validate their relation to questionnaire data of eyedness. METHODS: Conventional accounts of eye preference (German adaptation of Coren's questionnaire and a sighting task) were compared with various optometric tests of binocular function within a sample of 103 subjects. Examination included visual acuity and accommodation in each eye, stereoscopic prevalence, suppression due to binocular rivalry, fixation disparity (Mallett test). RESULTS: Sighting dominance was leftward in 32% and rightward in 68% of the cases and was highly correlated (Kendall's tau(b)=0.70) with eyedness. Further significant associations were restricted to stereoscopic prevalence which correlated with sighting dominance (tau(b)=0.55), eyedness (tau(b)=0.50), and rivalry dominance (tau(b)=0.28). CONCLUSION: Eye preference seems to be essentially reflected by eyedness, sighting dominance, and stereoscopic prevalence, but largely unrelated to fixation disparity, accommodation, and visual acuity.