放射状角膜切开术后矫正不足的再手术问题

Radial keratotomy:Reoperations After Undercorrection

27 radial keratotomy eyes underwent reoperations after undercorrection werereported.Reoperations were performed under the following circumstances:(1)morethan 1 year elapsed since the initial operation;(2)the uncorrected visual acuity wasworse than 4.7(20/40,0.5);(3)the spherical equivalent of the cycloplegic refractionwas greater than -1.00D of myopia.The methods of operation consisted of:(1)additionof 8 incisions to eyes that had an initial refractive error greater than-8.00D having hadan 8-incision procedure at the initial R K;(2)addition of 4 incisions to eyes that hadan initial myopia less than -4.00D and had a 4-incision procedure at the initial R K;(3)redeepening the initial shallow incisions which achievd a depth less than 75% of thecorneal thickness at the initial surgery;(4)proper centering the optical zone that waseccentrically placed at the initial operation.The average follow up after reoperation was18 months ranging from 6 months to 4 years.The average visual acuity increased by 4lines in 26 eyes ranging from 1 to 9 lines.All eyes became to have a lower myopiaafter reoperation,the average reduction was 2.3D ranging from 1 to 4D.