Astigmatism

"Functionally significant irregular astigmatism occurs most commonly in eyes that have had repeated operations or "creative keratotomy," consisting of intersecting radial and transverse incisions, combined radial and circumferential incisions, or incisions that extend too close to the line of sight. Such irregular astigmatism can greatly reduce visual function, not only decreasing spectacle-corrected visual acuity, but also producing glare and light sensitivity."

Dr George O Waring III, Refractive Keratotomy - 1992

"The most common examples, of improper RK technique are too many re operations and transverse incisions that cross or touch radial incisions. Both of these can lead to improper wound healing and frequently irregular astigmatism"

Dr Frank Thompson, Myopia Surgery - 1990

"Early techniques frequently used 16 and occasionally 32 incisions.  The profound corneal instability and irregular astigmatism that resulted from these additional incisions became increasingly undesirable and unnecessary as better results were obtained from eight, six, and often four-incision techniques."

Smolin and Thoft, The Cornea - 1994


Irregular astigmatism after radial and astigmatic keratotomy.

McDonnell PJ, Caroline PJ, Salz J

Source

Doheny Eye Institute, University of Southern California, School of Medicine, Los Angeles. 

Abstract

Eleven eyes of six patients, who had been referred for management of irregular astigmatism after receiving crossed incisions for myopic astigmatism, had moderate to marked irregular corneal astigmatism with marked flattening in the meridians of intersecting incisions. All six patients had a decrease in best-corrected visual acuity with spectacles after surgery. Visual acuity with spectacles was 20/40 in five of 11 eyes; with contact lenses it reached 20/40 in ten of 11 eyes. However, two patients could not wear the contact lenses because of lens decentration caused by the marked distortion in corneal topography. Even with contact lenses, visual acuity could only be improved to 20/25 or better in six of 11 eyes.

PMID:

2912115 [PubMed - indexed for MEDLINE]