January 23, 2003
Decentered Hyperopic LASIK with an Existing Off-Center Corneal Apex
Review of Refractive Surgery,Jan,2003
Corneal topographies show the right and left eyes of a 40-year-old patient 12 months s/p bilateral hyperopic LASIK for +3 D in each eye. Preoperatively, the examination was unremarkable with 20/20 best corrected visual acuity OU.In contrast to the right eye which has excellent vision, the patient’s left eye has poor vision, with persistent multiple ghost images and a reduced BCVA of 20/50 (MR=+0.75+1x80(Figure 1. A postoperative corneal topography showing a well centered hyperopic LASIK treatment ) Corneal topography of the left eye revealed the etiology of the problem. The steep region corresponding to the hyperopic treatment in the left eye appears to be inferiorly decentered.(Figure 2. The postoperative corneal topography of the contralateral eye of the same patient, showing an inferiorly decentered “second apex” created by hyperopic LASIK and the “first apex” (preexisting superiorly decentered corneal apex preop).
There appear to be double apices created by the superiorly off-centered naturally existing corneal apex (the upper apex) and the newly created inferiorly decentered second apex generated by the hyperopic LASIK. In contrast to a myopic treatment in which the corneal apex is flattened, a hyperopic treatment creates a new corneal apex.If the new apex is not in the same location as the existing corneal apex double apices can occur, which can create irregular astigmatism and reduce vision.This case demonstrates how corneal topography can play a critical role in revealing the etiology of poor visual quality after refractive surgery. The cause of loss of vision in the left eye of this patient is due to irregular astigmatism arising from an inferiorly decentered hyperopic LASIK treatment coupled with an existing superiorly off-centered corneal apex preoperatively
Posted by M Khanlari MD
Posted by at January 23, 2003 08:49 PM