To the Editor.
—This method can be used in the treatment of all cases of herpes keratitis. It is invaluable in the treatment of metaherpetic keratitis and keratitis profunda.Using multiple applications, the entire lesion is frozen and thawed at least three times under direct slip-lamp control with a cryoprobe having a very rapid defrost rate. A 2-mm retinal cryoprobe is applied warm, exerting a little pressure on the cornea. Application time is two to three seconds after actuation of the gas flow. The ice rim formed on the corneal surface around the probe helps in the assessment of the freezing depth. It is essential to freeze the entire depth of the lesion, stopping short of the endothelium in cases of deep stromal herpes. Nitrous oxide gas operating a cryoprobe (Joule Thomson) is used to give a probe tip temperature of−80 C.The patient arrives for the freezing treatment with
Amoils SP, Maier G. CRYOTHERAPY AND AUTOGENOUS SERUM THERAPY. Arch Ophthalmol. 1971;86(1):113-114. doi:10.1001/archopht.1971.01000010115021