Abstract
Purpose: :
To demonstrate the ability to restore accommodation by injecting a selected polymer in the emptied capsular bag of a living monkey eye.
Methods: :
After removing the natural lens of a rhesus monkey through a small peripheral rhexis, the capsular bag is treated with a modified viscoelastic solution to prevent LEC proliferation. Subsequently the bag is filled with a 2–component silicon polymer mixture and closed with a plug. The polymer mixture is cured at eye temperature into a polymer network with optical and mechanical properties similar to that of a 20 year old human lens. The operated eye receives three daily treatments with dexamethasone and gentamycine eye drops for as period of 2 weeks in order to prevent post–op inflammation.The refraction of the eye is measured with a Hartinger refractometer before and after pharmacological stimulation of accommodation. The lens thickness is measured with A–scan. The speed of sound of the artificial lens material is 1066 m/s.
Results: :
Postoperatively, the eyes were clear and Hartinger refraction measurements showed a good optical quality of the operated eye. Maximum accommodation amplitudes of 6D and maximum lens thickness changes of 0.5 mm were recorded. Nine months postoperatively accommodation amplitudes of 3 – 4 D were still measured.
Conclusions: :
A significant amount of accommodation can be restored in a rhesus monkey eye by replacing the natural crystalline lens with a full size polymer lens. This suggests that it must be possible to restore a functional level of human accommodation with injectable lenses.
Keywords: presbyopia • small incision cataract surgery • crystalline lens