Magnetic resonance imaging of aging, accommodating, phakic, and pseudophakic ciliary muscle diameters.

摘要: New strategies, including lens softening, refilling, scleral expansion, and potentially accommodating intraocular lenses (IOLs), are being developed to restore accommodation in presbyopic eyes.1–11 Because a functioning ciliary muscle is key each procedure or device, it increasingly important quantify vivo accommodative changes the aging of phakic pseudophakic eyes. Although iris obscures direct observation normal, intact human eye, magnetic resonance imaging (MRI) not impeded by allows complete visualization anterior segment. Although MRI used clinically diagnose number ocular disorders, because its expense unlikely at present be preoperatively for IOL sizing postoperatively clinical evaluation. Research applications include high-resolution retinal study extraocular muscles.12–20 In addition, Strenk et al.21 segment techniques instrumentation that permit geometric relationship between structures during with rest. These studies yielded new information on growth22 theory presbyopia development: Life-long increases thickness indirectly decrease circumlental space displacing and, hence, muscle, ultimately leading decreasing zonular tension response.23 This ability observe has also provided only statistically significant demonstration Helmholtz theory24 correct. found response an stimulus, ring diameter equatorial occurred, corresponding increase thickness. lenticular decreased advancing age, change was undiminished throughout life, mean value 0.661 mm. A possible trend toward slight contraction age but significant. However, limited people advanced were enrolled. The 25 subjects 39.10 years (range 22 83 years). Only 1 subject older than 62 years. Here, we expand range 91 provide more uniform distribution determine whether remains constant eye. Also, most strategies correction remove alter crystalline lens, additional preliminary data from subset presented.