versão impressa ISSN 0004-2749versão On-line ISSN 1678-2925
Arq. Bras. Oftalmol. vol.61 no.1 São Paulo fev. 1998
To evaluate the safety and efficacy of repeated excimer laser for treatment of residual myopia and astigmatism.
Eleven eyes (ten patients) with age ranging from 20 to 46 years underwent reablation with excimer laser. Six eyes (54.54%) were treated using photorefractive keratectomy (PRK), two (18.18%) epithelial phototherapeutic keratectomy (PTK-e) followed by PRK, and two (18.18%) with photoastigmatic keratectomy (PARK). Retreatment was done 5 to 16 month after the first treatment (average 9.3 ± 3.4 months) and follow-up ranged from 6 to 23 months (average 9.2 ± 5.4 months). The laser used was the Apex plus Summit excimer laser. Refractive changes, visual acuity and corneal haze were evaluated.
Mean preoperative spherical equivalent was -8.50 ± 3.66D. After the first treatment there was a reduction in the mean spherical equivalent of 55%, -4.04 ± 2.42D, statistically significant (p = 0.0004). After retreatment there was a reduction in the mean spherical equivalent of 28%o compared to the first treatment but this reduction was not statistically significant (p = 0.09). Pre-operative astigmatism was -2.41 ± 1.84. After the first (-2.30 ± 1.70) and second treatment (-2.10 ± 0.80) there was no significant reduction (p = 0.19 e p = 0.30 respectively). After retreatment 36.36% of the eyes presented an uncorrected visual acuity ≥ 20/40 and 63.63% ≥ 20/60. Thirty three percent were within ±1 diopter of emmetropia and 54.54% within 2 diopters. Five eyes (45.54%) lost between one to five lines of the best spectacle-corrected visual acuity after retreatment when compared to preoperative.
Excimer laser retreatment lacks efectivity in cases of high refractive residual ametropies. Decrease in the best corrected visual acuity may be expected as a side effect in these cases.
Key words: Photorefractive keratectomy; Myopia; Cornea; Surgery; Re-intervention; Complication