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Use of a urinary catheter to prevent fogging of the BIOM lens during vitrectomy

      The use of noncontact wide-angle viewing systems to perform vitrectomies has been widely adopted by vitreoretinal surgeons.

      American Society of Retina Specialists. Annual Preferences and Trends Survey, 2005. Slide 31. 〈www.asrs.org〉 (access for members only).

      Fogging of the Binocular Indirect Ophthalmo Microscope (BIOM 4; Oculus Surgical, Port St. Lucie, Fla.) lens during vitrectomy can be a problem in patients with deep-set orbits and in patients with small pupils in whom the BIOM lens has to be placed in close proximity to the cornea.
      • Murthy R.K.
      • Chalam K.V.
      Viewing systems for vitrectomy.
      Fogging is thought to be caused by humidity originating from the surface of the eye condensing on the cold BIOM lens. Antifogging agents applied to the BIOM lens have limited efficacy, and previously reported warming of the BIOM lens prevents buildup of condensation only when the procedure is short.
      • Gale J.S.
      • Oliver A.
      • Maunder L.M.
      Correspondence.
      We describe an alternative simple method to avoid fogging of the BIOM lens.
      The tip of a 14FR red latex urethral catheter is trimmed tangentially, leaving a rectangular opening on one side of the catheter. After proper draping of the surgical eye, and after placing the speculum, the trimmed tip is taped to the surgical drape as close to the medial canthus as possible using Steri-StripTM skin adhesives (3M, Minneapolis, Minn.) (Fig. 1). The other end of the catheter is connected with tubing to a wall suction outlet. The vacuum generated at the tip of the catheter in the medial canthal area removes the moisture generated by the ocular surface, and prevents the buildup of condensation on the viewing lens.
      Figure thumbnail gr1
      Fig. 1Trimmed edge of the urinary catheter taped the medial canthus, with the BIOM lens in position.
      We have used this technique during vitrectomy in around 400 cases. We have noted that the lens remains free of moisture for extended periods, even when it is in proximity to the cornea. When properly placed, the tube does not interfere with the movement of the BIOM lens or with instrument exchange in the nasal trocar. We also noted that the hissing sound generated by the vacuum at the tip of the catheter can be adjusted by decreasing the level of vacuum in the wall suction outlet without compromising the defogging ability of the catheter. The cost of a single sterile 14FR urinary catheter is around US $23.00, adding a minimal amount to the cost of surgery.
      The use of a 14FR urinary catheter connected to suction is a simple and affordable technique to prevent fogging of the BIOM lens during vitrectomy surgery.

      Acknowledgements

      Supported in part by Research to Prevent Blindness and the Pat & Willard Walker Eye Research Center.

      References

      1. American Society of Retina Specialists. Annual Preferences and Trends Survey, 2005. Slide 31. 〈www.asrs.org〉 (access for members only).

        • Murthy R.K.
        • Chalam K.V.
        Viewing systems for vitrectomy.
        in: Narendran V. Kothari A.R. Principles and practice of vitreoretinal surgery. Jaypee Brothers Medical Publishers, Delhi2014: 77
        • Gale J.S.
        • Oliver A.
        • Maunder L.M.
        Correspondence.
        Retina. 2008; 28: 784