a noncontact tonometer comprises an air current blowing means for blowing an air current against an eye , a cornea deformation measuring means for optically measuring a change in the shape of the cornea caused by the air current blowing means , and an arithmetic means capable of calculating the intraocular tension of the eye on the basis of the change in the shape of the cornea . since the intraocular tension of the eye can be calculated on the basis of the change in the shape of the cornea by the arithmetic means , the pressure of the air current blown against the eye need not be high , which lightens load on the subject .