PubMed · 7184838
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K A Hellner, K K Gauri. 1982. [Accommodation phosphenes].. https://pubmed.ncbi.nlm.nih.gov/7184838/
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The relationship between lenticular colloid osmotic (oncotic) pressure and intraocular pressure is discussed, with particular reference to a postulated buffering reservoir action of the lens in protecting against acute changes in intraocular pressure. A hypothesis is developed regarding acute lenticular volume changes in those species manifesting change in lens shape during accommodation. The unusually high colloid osmotic pressure of fish lenses is discussed and related to their unique means of accommodation and their susceptibility to cataract formation.
1. It has been hypothesized, but not verified empirically, that the control of human ocular accommodation is mediated by either the red-green or yellow-blue colour channels. Our goal was to determine experimentally whether the red-green channel by itself could influence the accommodative response. 2. To find out, we isolated the red-green channel through chromatic bandpass filtering and measured accommodation under dynamic and static conditions. The effect of this filtering was to modulate the red-green channel without disturbing either the yellow-blue or luminance channels. 3. Accommodative gain (ratio of response to stimulus amplitude) declined monotonically with decreasing bandwidth under dynamic conditions. Because the outputs of both the luminance and yellow-blue colour channels did not vary with bandwidth, the only explanation is that the red-green opponent process was responsible for the effect. 4. Under static conditions, however, accommodation was independent of bandwidth. This may be attributable to the decreased sensitivity to chromatic contrast that occurs at low temporal frequencies.
OBJECTIVES: To investigate the long-term motor stability and sensory outcome of patients with partly accommodative esotropia who were overcorrected surgically and in whom the hyperopic correction was reduced postoperatively, and to determine if those results depended on the amount of hyperopia present. DESIGN: A 15-year prospective study that analyzed 5-year outcome. Patients whose esotropia was not initially overcorrected were used as controls. PATIENTS: Of 382 patients who underwent surgery for partly accommodative esotropia, 22 were surgically overcorrected and were followed up for 5 years. RESULTS: Of the eight patients in the study group with 2.5 diopters or less of hyperopia in their fixing eye, seven had good motor alignment compared with four of 14 patients who had more than 2.5 diopters of hyperopia. Ninety-one percent (148/163) of the control patients who had greater than 2.5 diopters of hyperopia maintained good motor alignment 5 years after surgery compared with 29% of the study group patients. This difference was statistically significant. Of the eight study patients with less than 2.5 diopters of hyperopia, five developed good stereopsis compared with one of 14 patients with greater hyperopia. CONCLUSIONS: Surgical overcorrection in patients with partly accommodative esotropia with greater than 2.5 diopters of hyperopia may not be reversible by postoperative reduction in the hyperopic correction. It often is reversible, however, in patients with 2.5 diopters or less of hyperopia.