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Updated: Aug 4, 2026

Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo
Published on: July 1, 2013
Swelling of collagen intracanalicular implants
1Borish Center for Ophthalmic Research, School of Optometry Indiana University, Bloomington, IN 47405, USA.
Background:
Absorbable intracanalicular collagen implants are used to attempt to determine if permanent closure of the tear drainage system will diminish or alleviate the signs and symptoms of dryness. The rate of swelling of the collagen implants was measured in vitro in this study.
Methods:
Collagen implants were submersed in saline, Refresh Plus artificial tears or Tobrex antibiotic solution on a hanging drop microscope slide. The diameter of the collagen rod was measured over time using videotaping and image processing.
Results:
The 0.3- and 0.4-mm diameter collagen implants swelled approximately 55% to 65% in Unisol 4 Preservative Free saline and Refresh Plus artificial tear solution, with the majority of the swelling occurring over the first 30 minutes. The 0.4-mm diameter implants took slightly longer to reach the fully swollen state than did the 0.3-mm implants. They swelled somewhat less in Tobrex Ophthalmic Solution.
Conclusions:
Collagen implants swell approximately 60%, with the majority of the swelling occurring in the first 30 minutes. Thus, it will take approximately 30 minutes after insertion of the implants for the full occlusive effect to occur.

