Potential acuity meter for predicting postoperative visual acuity in penetrating keratoplasty. A new method using a hard contact lens

William E Smiddy, T. H. Horowitz, W. J. Stark, P. Klein, G. P. Kracher, A. E. Maumenee

Research output: Contribution to journalArticle

4 Scopus citations


An irregular corneal surface degrades the optical transmission and limits the effectiveness of the potential acuity meter (PAM) in predicting post-keratoplasty visual acuity. The authors investigated the efficacy of using a temporarily placed hard contact lens to neutralize surface irregularities in conjunction with the PAM in predicting post-keratoplasty visual acuity. A prospective evaluation was performed on 40 keratoplasty patients with a mean follow-up of 10.4 months. Of 27 patients with corneas clear enough to permit them to read letters on the PAM chart, 17 (63%) had very accurately predicted visual acuities by this new method, compared to only eight patients (30%) with the PAM alone. Three patients had predicted visions better than final vision, but this was due to a concurrent cataract in two cases and chronic cystoid macular edema (CME) in the third case. This study indicates that temporarily placing a hard contact lens for use with the PAM can increase its accuracy in predicting final visual acuity after penetrating keratoplasty.

Original languageEnglish
Pages (from-to)12-16
Number of pages5
Issue number1
StatePublished - Apr 17 1987
Externally publishedYes


ASJC Scopus subject areas

  • Ophthalmology

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