To the Editor.
—Examination of the retina and the anterior angle with a contact lens provides a clear view of ocular structures. The examination requires use of a transparent medium to form a bond between the lens and cornea. Currently, normal saline, 2.0% to 2.5% hydroxypropyl methylcellulose (Methocel, Gonak, or Goniosol), and a hydroxyethyl cellulose lubricant (K-Y jelly) are used.1There are disadvantages, however, to the use of these materials. First, the more viscous preparations are not easily washed away and leave a residue on the cornea, causing a minor change in visual acuity and degrading subsequent observations. Second, the residue causes photography and angiography to be of suboptimal quality, necessitating return visits for the patient. This is bothersome for both the patient and physician, and in rare instances progression of the ocular condition may occur during this interval. Third, some of these media contain preservatives, such as benzalkonium
Moffett DG. A New Lubricant (Carboxymethylcellulose) for Contact Lens Examination. Arch Ophthalmol. 1991;109(2):173. doi:10.1001/archopht.1991.01080020019003