Use of hydroxypropylmethylcellulose 2% for removing adherent silicone oil from silicone intraocular lenses

Background/aims: To investigate the effect of hydroxypropylmethylcellulose (HPMC) on the physical interaction (contact angle) between silicone oil and a silicone intraocular lens (IOL). Methods: In vitro experiments were performed, to determine the effect of HPMC (0.5%, 1% or 2%), with or without an additional simple mechanical manoeuvre, on the contact angle of silicone oil at the surface of both silicone and acrylic (control) IOLs. A balanced salt solution chamber was used. The study group comprised 21 silicone and nine acrylic IOLs. Results: The median contact angle of silicone oil on silicone IOL was 99 degrees. The addition of HPMC 2% alone did not significantly alter the contact angle. HPMC 2% combined with an additional single mechanical manoeuvre increased the contact angle to 180 degrees (greater non-wetting), with complete separation of silicone oil from silicone IOL within 1 min. The manoeuvre alone, or in conjunction with a lower concentration of HPMC (0.5 or 1%), was ineffective in increasing the contact angle. Conclusion: We present a novel, non-toxic technique of using hydroxypropylmethylcellulose 2% combined with a simple mechanical manoeuvre, for the removal of adherent silicone oil droplets from silicone intraocular lenses.