Surgical intervention and accommodative responses, I: centripetal ciliary body, capsule, and lens movements in rhesus monkeys of various ages.
OBJECTIVE
To determine how surgically altering the normal relationship between the lens and the ciliary body in rhesus monkeys affects centripetal ciliary body and lens movement.


METHODS
In 18 rhesus monkey eyes (aged 6-27 years), accommodation was induced before and after surgery by electrical stimulation of the Edinger-Westphal nucleus. Accommodative amplitude was measured by coincidence refractometry. Goniovideography was performed before and after intra- and extracapsular lens extraction (ICLE, ECLE) and anterior regional zonulolysis (ARZ). Centripetal lens/capsule movements, centripetal ciliary process (CP) movements, and circumlental space were measured by computerized image analysis of the goniovideography images.


RESULTS
Centripetal accommodative CP and capsule movement increased in velocity and amplitude after, compared with before, ECLE regardless of age (n = 5). The presence of the lens substance retarded capsule movement by approximately 21% in the young eyes and by approximately 62% in the older eyes. Post-ICLE compared with pre-ICLE centripetal accommodative CP movement was dampened in all eyes in which the anterior vitreous was disrupted (n = 7), but not in eyes in which the anterior vitreous was left intact (n = 2). After anterior regional zonulolysis (n = 4), lens position shifted toward the lysed quadrant during accommodation.


CONCLUSIONS
The presence of the lens substance, capsule zonular attachments, and Wieger's ligament may play a role in centripetal CP movement. The capsule is still capable of centripetal movement in the older eye (although at a reduced capacity) and may have the ability to produce approximately 6 D of accommodation in the presence of a normal, young crystalline lens or a similar surrogate.
Croft
Mary Ann
MA
Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA. macroft@wisc.edu
McDonald
Jared P
JP
James
Rebecca J
RJ
Heatley
Gregg A
GA
Lin
Ting-Li
TL
Lütjen-Drecoll
Elke
E
Kaufman
Paul L
PL
D000065:Accommodation, Ocular / Q000502:physiology*; D000375:Aging / Q000502:physiology*; D000818:Animals; D019923:Capsulorhexis / Q000379:methods; D002924:Ciliary Body / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006068:Gonioscopy; D007091:Image Processing, Computer-Assisted; D032801:Iridectomy / Q000379:methods; D007903:Lens Capsule, Crystalline / Q000502:physiology*; D007908:Lens, Crystalline / Q000502:physiology* / Q000601:surgery*; D008022:Ligaments / Q000502:physiology; D008253:Macaca mulatta; D008297:Male; D018918:Phacoemulsification / Q000379:methods; D012029:Refraction, Ocular