Use of the Perkins hand-held applanation tonometer in retinal detachment surgery.

The applanation method is generally accepted as being the most accurate for measuring intraocular pressure. Perkins (i965) described a hand-held portable applanation tonometer. Whitty (I969) reported his results using this tonometer: he found that readings with the hand applanator were slightly (I-I-5 mm.Hg) lower than those taken with the Haag-Streit tonometer, and he felt that this may have been caused by a slight defect in technique. There was no difference between the readings taken with the hand applanator when the patients were sitting and lying. In a list of uses to which the instrument may be put, Whitty mentioned the operating theatre. The purpose of this communication is to describe the indications and technique for its use in retinal detachment surgery. In this study, the battery-powered model (Fig. I, opposite) was used, and pressures were recorded in over fifty cases.