• New forms of refractive surgery result in corneas that are nearly doubled in thickness. To test the reliability of standard instrumentation for the measurement of intraocular pressure in such eyes, the MacKay-Marg tonometer was used on eye bank eyes with and without epikeratophakia lenticules and/or bandage contact lenses. The Goldmann applanation prism in the hand-held Perkins portable tonometer and the MacKay-Marg tonometer were used to measure IOP in vivo in a primate eye with an epikeratophakia graft. Measurements were compared with actual intraocular readings from a transducer. The MacKay-Marg tonometer was reliable at pressures above 20 mm Hg; the extra thickness of the graft and/or the rigidity of the contact lens impaired the accuracy below 20 mm Hg. The Goldman tonometer was accurate over the entire range of pressures.
Olson PF, McDonald MB, Werblin TP, Kaufman HE. Measurement of Intraocular Pressure After Epikeratophakia. Arch Ophthalmol. 1983;101(7):1111-1112. doi:10.1001/archopht.1983.01040020113019