Overestimation of Intraocular Pressure by Goldmann Applanation Tonometry Without Astigmatic Correction

A man in his mid-50s underwent 2 successive emergency penetrating keratoplasties for Candidal keratitis in his left eye. Significant postoperative astigmatism (K1 = 34.7@117, K2 = 45.2@27) led to marked overestimation of the intraocular pressure (56 mm Hg) as measured with Goldmann applanation tonometry with the mires in the standard horizontal position (Figure, A). With astigmatic correction, rotating the mires to 43° with respect to the more weakly refracting meridian,¹ the pressure measured 20 mm Hg (Figure, B), which was confirmed by rebound tonometry (17 mm Hg).