Magnetic resonance imaging of aging, accommodating, phakic, and pseudophakic ciliary muscle diameters
Accepted 27 May 2006.
Purpose
To quantify in vivo accommodative changes in the aging human ciliary muscle diameter in phakic and pseudophakic eyes.
Setting
Department of Surgery/Bioengineering, UMDNJ–Robert Wood Johnson Medical School, Piscataway, and the Institute of Ophthalmology and Visual Science UMDNJ–New Jersey Medical School, Newark, New Jersey, USA.
Methods
Images were acquired from 48 eyes of 40 people between the ages of 22 and 91 years, 1 eye of 32 phakic volunteers and both eyes of 8 patients who had monocular implantation of a single-piece AcrySof intraocular lens (IOL) (Alcon Laboratories). Images were acquired during physiological accommodation and with accommodation at rest, and the diameter of the ciliary muscle ring was measured.
Results
Results show the ciliary muscle remains active throughout life. The accommodative change in its diameter (mean 0.64 mm) (P<.00001) was undiminished by age or IOL implantation. Preliminary data showed that the accommodative decrease in muscle diameter in phakic and pseudophakic eyes was statistically identical. The phakic eyes had a marked decrease in ciliary muscle diameter with advancing age for both accommodative states (P<.000001 and P<.000001), which did not appear to be altered by IOL implantation. The lens equator was constant with age in the unaccommodated human eye, resulting in decreased circumlental space with advancing age in the phakic eyes.
Conclusion
Although the undiminished ability of the ciliary muscle to decrease its diameter with accommodation can be relied on in strategies for presbyopia correction, even in advanced presbyopia, the decreasing circumlental space and its potential effects on zonular tension must also be considered.
From the Department of Surgery/Bioengineering (S. Strenk), University of Medicine and Dentistry of New Jersey (UMDNJ)–Robert Wood Johnson Medical School, Piscataway, Institute of Ophthalmology and Visual Science (Guo), UMDNJ–New Jersey Medical School, Newark, and the Department of Biomedical Engineering (S. Strenk), Rutgers University, Piscataway, New Jersey, and MRI Research, Inc. (L. Strenk, S. Strenk), Cleveland, Ohio, USA
Corresponding author: S. Strenk, PhD, Department of Surgery/Bioengineering, UMDNJ–Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
Funded in part by National Eye Institute grants R43EY15655 (Dr. S.A. Strenk) and R01EY011529 (Dr. J. Semmlow).
No author has a financial or proprietary interest in any material or method mentioned.
ABSTRACT