The use of corticosteroid/beta-blocker combinations in the management of regression after PRK for high myopia.

After nearly 8 years of clinical experience, and with conflicting evidence from trials with and without corticosteroids, there is still no single, universally agreed postoperative management regimen for photorefractive keratectomy (PRK). All agree that corticosteroids will reverse sudden regressions, and so most still use varying corticosteroid regimens. In Hong Kong we are faced with many patients whose myopia is greater than -6 diopters (D), and we agree with the general observation that the regression/haze rate is much greater for these higher errors, and that increased intraocular pressure (IOP) seems to be associated with increased haze. We placed our high myopia group (greater than -6.00D) on corticosteroid/beta-blocker combinations and observed a much lower incidence of haze and regression from this group. We use this regimen now on all our patients and are achieving more accurate endpoint refraction and less haze. Our hypothesis is that lowering the IOP to less than 16 mm Hg reduces keratocyte migration by "tightening" the corneal lamellae, thus dampening the healing response. Case studies are presented to illustrate this relationship.