Emergence of the role of cataract and IOL surgery in the correction of refractive errors
The shifting trends in medical practice reflect the environmental factors that serve as the impetus for creative initiatives. In current cataract surgery, these factors include the excellent functional results of cataract surgical outcomes in eyes without significant comorbidities, the advances in technology for lens removal and for intraocular lens (IOL) materials and design, the desire of patients for functional vision that benefits their lifestyles, and, recently, the reduced reimbursement for cataract surgery. While any of these alone might have an effect on physicians' behaviors, the confluence of these factors has had an impact on the present view of cataract/IOL refractive surgery.
Refractive lens exchange is a viable technique that has emerged as a response to the factors enumerated above. Packer and coauthors1 have presented successful results of refractive lens exchange and implantation of a multifocal IOL in both myopic and hyperopic eyes. In this issue, Preetha et al. (pages 895–899) report their results of clear lens extraction with IOL implantation in hyperopic eyes. The results demonstrate improvement in visual acuity with good final refractive outcomes. Both publications suggest that refractive lens exchange offers greater predictability than alternative corneal refractive procedures. However, performing cataract surgery in eyes with high ametropia imposes technical considerations that should be recognized and included in the surgical plan during the evaluation process. Patient expectation of an excellent functional result is also high in this population.
Phakic IOL implantation is another procedure of growing interest in the United States. Most publications on this topic originate from work in South America and Europe. There are an increasing number of reports of successful implantation of anterior chamber and retroiridial phakic IOLs. The hope is that technical refinement and improvement of the design characteristics of these lenses will make this surgery a viable alternative to current refractive methods. This option is particularly attractive for eyes that cannot be satisfactorily treated with corneal refractive surgery. A concern with the implantable contact lens is cataract formation. Since the phakic IOL placed behind the iris may contact the surface of the crystalline lens, a localized cataract can develop. Gonvers and coauthors (pages 918–924) describe the relationship of phakic IOL vaulting to anterior subcapsular cataract (ASCC) formation. They conclude that cataract formation did not occur as a result of the surgical implantation since the crystalline lenses were clear at the 3-month evaluation and ASCCs developed subsequently. The authors recommend further modification of phakic IOL design to reduce the incidence of cataract formation that occurs because of contact between this particular phakic IOL and the clear lens.
Cataract surgery with IOL implantation is assuming its appropriate role in the spectrum of refractive surgical procedures. Many ophthalmologists accept refractive lens exchange as a procedure that offers a segment of their patient population the benefit of improved functional vision. Eyes with higher degrees of ametropia should achieve similar benefits once critical aspects of phakic IOL design are refined.
© 2003 by Lippincott Williams & Wilkins, Inc.
1. Packer M, Fine IH, Hoffman RS. Refractive lens exchange with the Array multifocal intraocular lens. J Cataract Refract Surg 2002; 28:421-424