Oedematous corneal response of the fellow control eye to lotrafilcon a and vifilcon a hydrogel contact lenses in the rabbit.

Purpose: To compare central corneal swelling after 24 h in eyes wearing Lotrafilcon A (high Dk silicone hydrogel) and Vifilcon A (low Dk hydrogel) lenses and the fellow control eyes of rabbits.

Methods: 24 New Zealand albino rabbits, free of corneal and conjunctival disease, were anaesthetised with ketamine and xylazin. In 12 rabbits, the right eye was fit with the high Dk Lotrafilcon A silicone hydrogel lens. In the other 12 rabbits, the right eye was fit with the low Dk Vifilcon A hydrogel lens, whereas the left eyes were kept as control eyes. Thereafter, the lens-fitted eyes had partial tarsorrhaphy that left a central gap of approximately 4 mm in length. After 24 h the eyelids were opened and the lenses removed. Central corneal thickness was measured using an ultrasonic pachymeter (Mentor O&O-Advent).

Results: Central corneal oedema induced by Vifilcon A lens was significantly higher than that with the Lotrafilcon A lens (p < 0.0001). The oedema of the fellow eyes paired with the Vifilcon A lens-wearing eyes was also higher than that of the fellow eyes paired with the Lotrafilcon A lens-wearing eyes (p < 0.01).

Conclusions: The Lotrafilcon A lens induced significantly less corneal oedema than the Vifilcon A lens. Corneal oedema of the fellow eyes appears to be influenced by the swelling of the contralateral lens-wearing eyes. The oedema of the fellow control eye was significantly lower when there was less oedema in the contralateral eye wearing a high Dk silicone hydrogel lens. This may be a sympathetic physiological response. The presence of silicone in the high Dk hydrogel lens may suppress corneal oedema in the lens-wearing eye, thus affecting the fellow eye.