Edinger–Westphal stimulated accommodative dynamics in anesthetized, middle-aged rhesus monkeys

Baumeister, Martín; Wendt, Mark; Glasser, Adrian

doi:10.1016/j.exer.2007.09.002

Cited by 11 publications

(4 citation statements)

References 42 publications

(72 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3a, 3d, 3f). This suggests that the saturation of peak velocity observed here and in previous experiments17,33,35 does not reflect an upper limit of velocity that the accommodative system is capable of generating for a given response amplitude 36. There was no obvious correlation between the magnitude of adaptation and the subject's age (18–34 years) in the small number of individuals we tested ( n = 15).…”

Section: Discussioncontrasting

confidence: 48%

Short-Term Adaptive Modification of Dynamic Ocular Accommodation

Vedamurthy

Schor

2009

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

Purpose Indirect observations suggest that the neural control of accommodation may undergo adaptive recalibration in response to age-related biomechanical changes in the accommodative system. However, there has been no direct demonstration of such an adaptive capability. This investigation was conducted to demonstrate short-term adaptation of accommodative step response dynamics to optically induced changes in neuromuscular demands. Methods Repetitive changes in accommodative effort were induced in 15 subjects (18–34 years) with a double-step adaptation paradigm wherein an initial 2-D step change in blur was followed 350 ms later by either a 2-D step increase in blur (increasing-step paradigm) or a 1.75-D step decrease in blur (decreasing-step paradigm). Peak velocity, peak acceleration, and latency of 2-D single-step test responses were assessed before and after 1.5 hours of training with these paradigms. Results Peak velocity and peak acceleration of 2-D step responses increased after adaptation to the increasing-step paradigm (9/12 subjects), and they decreased after adaptation to the decreasing-step paradigm (4/9 subjects). Adaptive changes in peak velocity and peak acceleration generalized to responses that were smaller (1 D) and larger (3 D) than the 2-D adaptation stimulus. The magnitude of adaptation correlated poorly with the subject's age, but it was significantly negatively correlated with the preadaptation dynamics. Response latency decreased after adaptation, irrespective of the direction of adaptation. Conclusions Short-term adaptive changes in accommodative step response dynamics could be induced, at least in some of our subjects between 18 and 34 years, with a directional bias toward increasing rather than decreasing the dynamics.

show abstract

Section: Discussioncontrasting

confidence: 48%

Short-Term Adaptive Modification of Dynamic Ocular Accommodation

Vedamurthy

Schor

2009

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

show abstract

“…4 – 6 The parasympathetic innervation originating in the Edinger-Westphal nucleus carried by oculomotor nerve (cranial nerve 3) through the ciliary ganglion regulates the ciliary muscle. 7 – 9 Although there are aging changes in each of these components of accommodation, age-related changes in the lens correlate best with the age-dependent decrease in accommodative amplitude. 10 – 14 …”

mentioning

confidence: 99%

Protein Disulfide Levels and Lens Elasticity Modulation: Applications for Presbyopia

Garner¹,

Garner²

2016

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

PurposeThe purpose of the experiments described here was to determine the effects of lipoic acid (LA)-dependent disulfide reduction on mouse lens elasticity, to synthesize the choline ester of LA (LACE), and to characterize the effects of topical ocular doses of LACE on mouse lens elasticity.MethodsEight-month-old mouse lenses (C57BL/6J) were incubated for 12 hours in medium supplemented with selected levels (0–500 μM) of LA. Lens elasticity was measured using the coverslip method. After the elasticity measurements, P-SH and PSSP levels were determined in homogenates by differential alkylation before and after alkylation. Choline ester of LA was synthesized and characterized by mass spectrometry and HPLC. Eight-month-old C57BL/6J mice were treated with 2.5 μL of a formulation of 5% LACE three times per day at 8-hour intervals in the right eye (OD) for 5 weeks. After the final treatment, lenses were removed and placed in a cuvette containing buffer. Elasticity was determined with a computer-controlled instrument that provided Z-stage upward movements in 1-μm increments with concomitant force measurements with a Harvard Apparatus F10 isometric force transducer. The elasticity of lenses from 8-week-old C57BL/6J mice was determined for comparison.ResultsLipoic acid treatment led to a concentration-dependent decrease in lens protein disulfides concurrent with an increase in lens elasticity. The structure and purity of newly synthesized LACE was confirmed. Aqueous humor concentrations of LA were higher in eyes of mice following topical ocular treatment with LACE than in mice following topical ocular treatment with LA. The lenses of the treated eyes of the old mice were more elastic than the lenses of untreated eyes (i.e., the relative force required for similar Z displacements was higher in the lenses of untreated eyes). In most instances, the lenses of the treated eyes were even more elastic than the lenses of the 8-week-old mice.ConclusionsAs the elasticity of the human lens decreases with age, humans lose the ability to accommodate. The results, briefly described in this abstract, suggest a topical ocular treatment to increase lens elasticity through reduction of disulfides to restore accommodative amplitude.

show abstract

“…Finding a suitable model is difficult because there are considerable differences between species regarding the existence, the mechanism, and the amplitude of accommodation [66]. With such experiments, the linear dependence of biometric data such as lens thickness, lens diameter, and anterior chamber depth on the accommodative amplitude have been shown [68,69], and the relationship between amplitude and dynamics of accommodation have been characterized [70,71]. The most frequently used animal model for human accommodation is the rhesus monkey.…”

Section: Experimental Studies Of Accommodation In Vivomentioning

confidence: 99%

“…70 The second half of the IOL is then explanted. A Kuglen or Sinskey hook may also be used to position the segment for ease of removal as well as for counter-traction on the eye…”

mentioning

confidence: 99%