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D. G. Brady, A. Gwon, R. F. Steinert, R. Jain; Mechanics of the Capsular Bag and Zonules in Rabbit and Human Donor Eyes: A Comparative Study. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3828.
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© ARVO (1962-2015); The Authors (2016-present)
The present study is a continuation of a human donor eye study that assessed lens capsular bag elasticity with and without mechanical interaction of the zonules (ARVO 2006). As the rabbit is a good animal model for IOL studies, it is our goal to compare the mechanical properties of the young rabbit lens capsular bag to that of the aged human donor eye in order to better understand the dynamics of the capsular bag during accommodation in the non-aged human aphakic eye.
Six fresh New Zealand White (NZW) rabbit donor eyes from 3 rabbits approximately 3.5 months in age and 2.9 kg in weight and six fresh human donor eyes, ages 60 to 68 (approximately 72 hours postmortem) were studied. White-to-white diameter, equatorial diameter and axial length were measured. The cornea and iris were removed and the capsulorrhexis and the lens capsule bag diameter were measured in two axes before and after lens extraction. The same measurements were made ex vivo after cutting one-fourth, one-half or all of the zonules. All measurements were performed using digital calipers with an accuracy of ±0.01 mm.
The mean natural lens diameter of the NZW rabbit was 10.42 mm compared to 9.92 mm in the human eye. The mean lens capsule bag diameter slightly decreased following lens extraction to 10.33 mm in the rabbit and increased slightly in the human to 10.29 mm. Following refilling with Healon and complete zonular removal, the mean lens capsule bag diameter was 9.72 in the rabbit and 9.08 mm in the human. There is a mean difference of 0.7 mm between the natural lens of the young rabbit and a capsular bag that no longer has zonular attachments, which was similar to the aged human donor eye. Thus, without zonular attachment, the isolated capsular bag diameter decreases to less than its natural crystalline lens size by approximately 0.7 mm.
The 3.5 month old NZW rabbit eye appears to be similar to the aged human eye and may be a reasonable model for the evaluation of intraocular lenses designed to work with lens capsular elasticity in facilitating accommodation in the pseudophakic eye.
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