Photorefractive Keratectomy for Correction of Epikeratophakia
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CASE REPORTS AND SMALL CASE SERIES high myopia resulting from poste- results might be related to the pre- Photorefractive Keratectomy rior lenticonus. Postsurgical refrac- existing corneal stromal abnormali- for Correction of tion was stable for 8 years, then a ties in their patients, which were not Epikeratophakia Regression rapid myopic regression of the epi- observed in our group. Thus, PRK keratophakic lenses was observed can effectively be used to treat epi- Excimer laser photorefractive kera- the following year (Table). In- keratophakic regressed lenses in a se- tectomy (PRK) is widely used for the stead of removing the failed epikera- lected group of patients in whom correction of myopia, astigmatism, tophakic lenses, we performed PRK both the epikeratograft and the sur- and hyperopia.1,2 It has also been on the eyes. rounding cornea are clear. This used for correction of astigmatism method eliminates the need for re- after penetrating keratoplasty.3 Results. Two and a half years after moval of the epikeratograft and ex- Epikeratophakia has been used PRK, the refraction in all 4 eyes is posing the patient to the risks of suc- in the treatment of nontolerant con- stable and the epigrafts are clear. The cessive penetrating keratoplasty. tact lens keratoconous patients.4,5 Table presents the refraction and vi- The epigrafts were made from ma- sual acuity results for the eyes be- Hirsh Ami, MD chined corneal tissue that was found fore PRK and at 3 months, 1 year, Solberg Yoram, MD, PhD unsuitable for penetrating kerato- and 21⁄2 years after PRK. No haze has Cahana Michael, MD plasty. Long-term follow-up of pe- developed during this period. In all Avni Isaac, MD diatric patients who underwent epi- 4 eyes, a thin brown deposit ring was Tel-Hashomer, Israel keratoplasty for optical correction of formed on the edge of the treated op- aphakia and were corrected for em- tical zone. Corresponding author: Yoram Sol- metropia revealed that later in life berg, MD, PhD, The Goldschleger there is delayed myopic regression Comment. We describe herein our Eye Institute, Sheba Medical Center, of the treated eye, which required successful experience with PRK for Tel-Hashomer 52621, Israel (e-mail: further correction.6,7 In their pa- regressed epikeratophakic lenses. Af- [email protected]). 8 1 tients, Colin et al failed to correct ter a follow-up of 2 ⁄2 years, the re- 1. Seiler T, McDonnell P. Excimer laser photore- this myopic regression with PRK. sults were stable and the epigrafts fractive keratectomy: major review. Surv Oph- thalmol. 1995;40:89-110. We describe our experience with were clear. The eyes were also stable 2. Wu HK, Remers PZ. Photorefractive keratectomy PRK for correction of delayed my- with regard to the best-corrected vi- for myopia. Ophthalmic Surg Lasers. 1996;27: opic regression of epikeratophakia sual acuity. 29-44. 8 3. Campos M, Hertzog L, Garbus J, Lee M, McDon- in 4 eyes. Colin et al reported on 5 eyes nell P. Photorefractive keratectomy for severe kera- with delayed refractive regression toplasty astigmatism. Am J Ophthalmol. 1992;114: Design. All procedures were per- following myopic epikeratoplasty 429-436. 4. Kaufman HE, Werblin TP. Epikeratophakia for formed in the cornea and refractive that were treated with PRK. Al- the treatment of keratoconous. Am J Ophthal- surgery unit of The Goldschleger Eye though the eyes were successfully mol. 1982;93:342-347. 5. McDonald MB, Koling SB, Sabir A, Kaufman HE. Institute, Sheba Medical Center, Tel- corrected for emmetropia, all of them On-lay lamellar keratoplasty for the treatment of Hashomer, Israel. developed substantial subepithe- keratoconous. Br J Ophthalmol. 1983;67:615-618. Four eyes of 2 twin sisters un- lial haze with poor visual acuity, and 6. Arffa RC, Marelli TL. Long term follow-up of refractive and keratometric results of pediatric derwent epikeratoplasty at the ages the epikeratophakic lenses had to be epikeratophakia. Arch Ophthalmol. 1986;104: of 8 and 9 years old because of very removed. It is possible that their poor 668-670. Refraction and Visual Acuity Results Refraction, Degrees (Visual Acuity) Patient 1 Patient 2 Time Right Eye Left Eye Right Eye Left Eye Before epikeratophakia −12.50 −11.00 −16.00 −15.00 5 y after epikeratophakia −3.5 −2.0 3 30 (6/15p) −3.5 −1.0 3 100 (6/20) −5.0 −1.0 3 100 (6/15) −5.0 −3.0 3 180 (6/12) Before PRK −17.00 (6/12) −11.00 (6/12p) −17.00 (6/12p) −16.00 (6/12p) 3 mo after PRK −0.75 −2.0 3 15 (6/12+) −3.0 −3.5 3 160 (6/15) −3.75 −2.0 3 15 (6/12) −4.0 −3.0 3 170 (6/15) 1 y after PRK −1.0 −2.0 3 45 (6/12+) −2.0 −3.0 3 135 (6/12) −4.0 −2.0 3 25 (6/12p) −5.0 −3.0 3 170 (6/12+) 21⁄2 y after PRK −3.00 (6/15+) −2.5 −2.5 3 135 (6/12) −3.00 (6/12p) −4.0 −2.0 3 180 (6/12p) *PRK indicates photorefractive keratectomy; p, partial. Boldface items indicate best-corrected visual acuity. ARCH OPHTHALMOL / VOL 118, FEB 2000 WWW.ARCHOPHTHALMOL.COM 281 ©2000 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 7. Neumann AC, McCarty G, Sanders DV. Delayed regression of effect in myopic keratophakia ver- sus myopic keratomileusis for high myopia. Re- 101.5 3.3 101.5 3.3 fract Corneal Surg. 1989;5:161-166. 96.5 3.5 96.5 3.5 8. Colin J, Sangiuolo R, Malet F, Volant A. Photore- fractive keratectomy following undercorrected 91.5 3.7 91.5 3.7 myopic epikeratoplasties. J Fr Ophthalmol. 1992; 86.5 3.9 86.5 3.9 15:384-388. 81.5 4.1 81.5 4.1 76.5 4.4 76.5 4.4 71.5 4.7 71.5 4.7 Iatrogenic Keratoconus: 66.5 5.1 66.5 5.1 Corneal Ectasia Following 61.5 5.5 61.5 5.5 Laser In Situ Keratomileusis 56.5 6.0 56.5 6.0 50.5 6.7 50.5 6.7 for Myopia 49.0 6.9 49.0 6.9 47.5 7.1 47.5 7.1 Laser in situ keratomileusis (LASIK) 46.0 7.3 46.0 7.3 to correct myopia is performed by par- 44.5 7.6 44.5 7.6 tially resecting a prescribed thick- ness of stroma, removing corneal tis- 43.0 7.8 43.0 7.8 sue from the exposed stromal bed 41.5 8.1 41.5 8.1 using the excimer laser, and then re- 40.0 8.4 40.0 8.4 placing the resected stromal tissue. 38.5 8.8 38.5 8.8 This results in a substantial reduc- 37.0 9.1 37.0 9.1 tion of the biomechanically effective 35.5 9.5 35.5 9.5 stress-bearing thickness of cornea pro- 29.0 11.6 29.0 11.6 vided by the residual stromal bed. 24.0 14.1 24.0 14.1 There is concern that at some point, 19.0 17.8 19.0 17.8 the tensile strength of the cornea 14.0 24.1 14.0 24.1 might be reduced to the degree that 9.0 37.5 9.0 37.5 progressive ectasia ensues, thereby Diop mm Diop mm resulting in steepening of the cor- nea, irregular astigmatism, and pro- Figure 1. Top, Preoperative corneal topographic map of the right eye demonstrating focal inferonasal steepening. Bottom, Preoperative corneal topographic map of the left eye demonstrating a gressive myopia. This becomes a par- homogeneously regular central corneal contour. Drop indicates diopters. ticularly contentious issue when, in the absence of classic clinical evi- gery demonstrated mild inferona- Technologies, Waltham, Mass) in dence of keratoconus, inferior steep- sal steepening with a maximum the stromal beds of the right and left ening of the cornea seen on corneal power of 44.5 diopters (D), simu- eyes, respectively, estimated to leave topographic scan suggests the possi- lated keratometry readings of residual stromal beds of 260 µm OD bility of subclinical keratoconus. 43.0 3 134/41.5 3 44, and a mini- and 290 µm OS. On the first post- Herein, we report such a case of pro- mum keratometry reading of operative day, the patient’s uncor- gressive ectasia following LASIK. 41.3 3 37 (Figure 1, top). Kera- rected visual acuity was 20/40 OD toconus screening by Rabinowitz/ and 20/60 OS, but at the next ex- Report of a Case. A 23-year-old His- McDonnell criteria suggested the amination 6 weeks later, it had de- panic man sought refractive surgery presence of keratoconus, while creased to 20/400 OU, and his cor- to correct myopia. Prior to surgery, screening by Klyce/Maeda criteria rected visual acuity was 20/400 OD he relied on spectacles to correct his identified a 15% similarity to kera- and 20/30 OS with a refraction of vision. He reported infrequent toconus. Corneal topographic scans –5.50 sphere OU. A bilateral simul- changes in his prescription and good of the left eye showed a homoge- taneous enhancement procedure was visual acuity in the years prior to con- neously regular central corneal performed under the flaps to fully sultation. His optometrist’s records contour with a central corneal correct the estimated residual myo- prior to surgery documented a re- power of approximately 41.28 D pia, and on the next examination 2 fraction of –12.75 – 2.25 3 65 OD (Figure 1, bottom).