Cataracts and the surgical control of astigmatism

guest editorial Cataracts and the surgical control of astigmatism Astigmatism is a unique refractive error that produces reduced visual acuity and symptoms such as glare, monocular dyplopia, asthenopia, and distortion. Even when fully corrected with glasses, astigmatism may cause off-axis blur, eye strain, glare, and visual field restriction. Modification and control of astigmatism has been a long-time goal of ophthalmology and a great concern to the cataract surgeon. With the advent of intraocular lenses, the problem has become more acute, and with the proven safety of modern cataract and lens implant surgery, surgeons are giving more attention to intraoperative and postoperative astigmatism control. Although improvements such as diamond blades, smaller corneal needles, better suture material, and surgical keratometry have reduced the incidence of high degrees of postoperative astigmatism, both preexisting and postoperative astigmatism remain a problem. Refractive surgery for astigmatism gained popularity in the 1960s when corneal wedge resection and corneal relaxing incisions were first used to correct astigmatism following keratoplasty and cataract surgery. The introduction of radial keratotomy increased our knowledge about modifying astigmatism by corneal incisional techniques, and analysis of cataract incision modifications has taught us much about astigmatism control in cataract surgery. But despite these advances, the management of astigmatism remains a problem and many questions are unanswered. In this special issue, we look at the surgical management of astigmatism from various perspectives. In the first section, several articles examine the basic analysis of corneal responses to relaxing incisions. Agapitos et

aI., Flaharty and Siepser, and Neumann et al. present basic studies in the evaluation of astigmatic keratotomy. Next, both Osher and Davison present methods of correcting preexisting astigmatism at the time of cataract surgery. This section concludes with a review of methods of astigmatism reduction in cataract surgery by Maloney et al. The next section begins with a look at the practical application of astigmatic procedures in correcting astigmatism in implant surgery with articles by Shepherd and Cory, with emphasis on small incision cataract surgery. Cravy then looks at the effect of sutures on astigmatism. Small incisions and scleral pocket incisions and their relationship to astigmatism are presented by Masket, Neumann et aI., and Shepherd and further studied in a case report by Kansas. In another case report, pathologic astigmatism and its correction is presented by Dubroff. A new instrument for improved accuracy in astigmatic keratotomy is presented, and to round out the issue, the consultation section presents a difficult case of management of partial wound dehiscence with significant uniocular against-the-rule astigmatism. We hope that this special issue will stimulate debate and further research as we seek to provide even better functional results from our cataract and refractive surgical procedures. Readers are encouraged to compare their experience with these authors and study their own cases. Data analysis of properly done studies will add to our understanding of this important subject.

J CATARACT REFRACT SURG-\'OL 15, JANUARY 1989

Spencer P. Thornton, M. D.

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