Customized Topography-guided Photorefractive Keratectomy With the MEL-70 Platform and Mitomycin C to Correct Hyperopia After Radial Keratotomy

Abstract

<h4>PURPOSE</h4><p>To evaluate topography-guided photorefractive keratectomy (PRK) for correcting hyperopia and astigmatism after radial keratotomy (RK).</p> <h4>METHODS</h4><p>Prospective study of 12 consecutive patients (19 eyes) who were treated with topography-guided PRK with 0.02% mitomycin C using an Asclepion-Meditec MEL-70 excimer laser with a 9.5-mm ablation zone. All eyes were operated by the same surgeon and followed for 1 year.</p> <h4>RESULTS</h4><p>Thirteen eyes had complete epithelialization by day 7 and all eyes by day 10. At 1 year, uncorrected visual acuity was 20/25 or better in 42.1% of eyes and 20/40 or better in 68.4%. Preoperative mean spherical equivalent refraction was +3.80±2.47 diopters (D) and +0.24±2.36 D (<i>P</i><.001) 1 year postoperative, with 47.4% of eyes being within ±1.00 D and 73.7% within ±2.00 D. Preoperative mean cylinder was –2.30±1.41 D and –0.62±0.73 D (<i>P</i><.001) 1 year postoperative. At 1 year, 68.4% of eyes gained at least 1 line of best-spectacle corrected visual acuity, 36.8% gained more than 1 line, and only 2 eyes lost 1 line (one due to corneal haze). Three eyes developed central haze. Mean regression from 6 to 12 months in these 3 eyes was +1.83 D and in the remaining 16 eyes was –0.50 D. </p> <h4>CONCLUSIONS</h4><p>Topography-guided PRK with mitomycin C was safe and reasonably effective for the treatment of hyperopia after RK. [<cite>J Refract Surg</cite>. 2008;24:911-922.]</p> <h4>AUTHORS</h4> <p>From Sadalla Amin Ghanem Eye Hospital, Joinville, SC, Brazil (R.C. Ghanem, V.C. Ghanem, Souza, E.A. Ghanem); Department of Ophthalmology, University of São Paulo, São Paulo, SP, Brazil (R.C. Ghanem, V.C. Ghanem, Kara-José); and Department of Ophthalmology, State University of Campinas, SP, Brazil (Kara-José).</p> <p>The authors have no commercial or proprietary interest in the materials presented herein.</p> <p>Correspondence: Ramon C. Ghanem, MD, Sadalla Amin Ghanem Eye Hospital, 172 Abdon Batista St, Joinville, SC 89201, Brazil. Tel: 55 47 3433 5333; Fax: 55 47 3433 5955; E-mail: <a href="mailto:ramonghanem@gmail.com">ramonghanem@gmail.com</a></p> <p>Received: May 25, 2007</p> <p>Accepted: November 27, 2007</p> <p><b>Posted online: April 30, 2008</b></p>

Photorefractive keratectomy in the management of postradial keratotomy hyperopia and astigmatism

“…In our study, 23% of patients achieved 20/20 UDVA, and 84% achieved 20/40. Such findings are in correspondence to other reports, in which a UDVA of 20/40 or better was observed in 70%;[ 19 ] 65%,[ 11 ] 82%,[ 9 ] 96%,[ 13 ] and 91%. [ 12 ]…”

“…[ 18 19 20 ] Although either mechanical microkeratome or the femtosecond LASIK surgeries have shown favorable initial outcomes, such methods are not without complications. [ 18 19 ] Flap-related issues, especially epithelial in growth and splitting RK incisions can cause flap fragmentation along with the possibility corneal ectasia. Due to such possibilities, some authors believe that LASIK should be avoided in eyes with more than 8 RK incisions.…”

“…Due to such possibilities, some authors believe that LASIK should be avoided in eyes with more than 8 RK incisions. [ 18 19 ] About the advantages of PRK over LASIK, the following points are noteworthy: first: PRK avoids additive weakening of the cornea, as a risk factor of ectasia; and second: PRK does not interrupt with RK incisions, saving the remaining corneal structural integrity. [ 20 ] Corneal ectasia has occurred neither in the present study nor in our daily practice over recent years.…”

Photorefractive keratectomy in the management of postradial keratotomy hyperopia and astigmatism

“…In our study, 23% of patients achieved 20/20 UDVA, and 84% achieved 20/40. Such findings are in correspondence to other reports, in which a UDVA of 20/40 or better was observed in 70%;[ 19 ] 65%,[ 11 ] 82%,[ 9 ] 96%,[ 13 ] and 91%. [ 12 ]…”

“…[ 18 19 20 ] Although either mechanical microkeratome or the femtosecond LASIK surgeries have shown favorable initial outcomes, such methods are not without complications. [ 18 19 ] Flap-related issues, especially epithelial in growth and splitting RK incisions can cause flap fragmentation along with the possibility corneal ectasia. Due to such possibilities, some authors believe that LASIK should be avoided in eyes with more than 8 RK incisions.…”

“…Due to such possibilities, some authors believe that LASIK should be avoided in eyes with more than 8 RK incisions. [ 18 19 ] About the advantages of PRK over LASIK, the following points are noteworthy: first: PRK avoids additive weakening of the cornea, as a risk factor of ectasia; and second: PRK does not interrupt with RK incisions, saving the remaining corneal structural integrity. [ 20 ] Corneal ectasia has occurred neither in the present study nor in our daily practice over recent years.…”

Sequential Customized Therapeutic Keratectomy in Patients With a History of Radial Keratotomy

“…Patients with reduced visual acuity and aberrations due to previous RK have been treated by photorefractive keratectomy (PRK), [21][22][23][24][25] LASIK, [26][27][28][29] corneal crosslinking, 30 deep anterior lamellar keratoplasty (DALK), 31 Bowman's layer onlay graft, 32 and corneal suturing or redeepening of the incisions. 33 Of these published studies, PRK was the most effective for overall visual acuity improvement, particularly when topography-guided procedures helped to increase surface regularity and improve predictability of results by customized ablation.…”

The Impact of Epithelial Remodeling on Surgical Techniques Used in Topography-guided Surface Ablation in Irregular Corneas

“…Unlike the current whole-eye wavefront-guided approaches, topography-guided ablation directly addresses corneal optical irregularities at their source, and is often the preferred method in therapeutic corneal refractive surgery 18,19,24. Still, suboptimal outcomes after surface ablation of irregular corneas with topography-guided PRK have been reported when mechanical or alcohol epithelial removal preceded the ablation,34,35 as in our conventional anterior topography-guided PRK (Type 1).…”

Photorefractive keratectomy in the management of postradial keratotomy hyperopia and astigmatism

“…In our study, 23% of patients achieved 20/20 UDVA, and 84% achieved 20/40. Such findings are in correspondence to other reports, in which a UDVA of 20/40 or better was observed in 70%;[ 19 ] 65%,[ 11 ] 82%,[ 9 ] 96%,[ 13 ] and 91%. [ 12 ]…”

“…[ 18 19 20 ] Although either mechanical microkeratome or the femtosecond LASIK surgeries have shown favorable initial outcomes, such methods are not without complications. [ 18 19 ] Flap-related issues, especially epithelial in growth and splitting RK incisions can cause flap fragmentation along with the possibility corneal ectasia. Due to such possibilities, some authors believe that LASIK should be avoided in eyes with more than 8 RK incisions.…”

“…Due to such possibilities, some authors believe that LASIK should be avoided in eyes with more than 8 RK incisions. [ 18 19 ] About the advantages of PRK over LASIK, the following points are noteworthy: first: PRK avoids additive weakening of the cornea, as a risk factor of ectasia; and second: PRK does not interrupt with RK incisions, saving the remaining corneal structural integrity. [ 20 ] Corneal ectasia has occurred neither in the present study nor in our daily practice over recent years.…”

Sequential Customized Therapeutic Keratectomy in Patients With a History of Radial Keratotomy

“…Patients with reduced visual acuity and aberrations due to previous RK have been treated by photorefractive keratectomy (PRK), [21][22][23][24][25] LASIK, [26][27][28][29] corneal crosslinking, 30 deep anterior lamellar keratoplasty (DALK), 31 Bowman's layer onlay graft, 32 and corneal suturing or redeepening of the incisions. 33 Of these published studies, PRK was the most effective for overall visual acuity improvement, particularly when topography-guided procedures helped to increase surface regularity and improve predictability of results by customized ablation.…”

The Impact of Epithelial Remodeling on Surgical Techniques Used in Topography-guided Surface Ablation in Irregular Corneas

“…Unlike the current whole-eye wavefront-guided approaches, topography-guided ablation directly addresses corneal optical irregularities at their source, and is often the preferred method in therapeutic corneal refractive surgery 18,19,24. Still, suboptimal outcomes after surface ablation of irregular corneas with topography-guided PRK have been reported when mechanical or alcohol epithelial removal preceded the ablation,34,35 as in our conventional anterior topography-guided PRK (Type 1).…”

Photorefractive keratectomy in the management of postradial keratotomy hyperopia and astigmatism

“…In our study, 23% of patients achieved 20/20 UDVA, and 84% achieved 20/40. Such findings are in correspondence to other reports, in which a UDVA of 20/40 or better was observed in 70%;[ 19 ] 65%,[ 11 ] 82%,[ 9 ] 96%,[ 13 ] and 91%. [ 12 ]…”

“…[ 18 19 20 ] Although either mechanical microkeratome or the femtosecond LASIK surgeries have shown favorable initial outcomes, such methods are not without complications. [ 18 19 ] Flap-related issues, especially epithelial in growth and splitting RK incisions can cause flap fragmentation along with the possibility corneal ectasia. Due to such possibilities, some authors believe that LASIK should be avoided in eyes with more than 8 RK incisions.…”

“…Due to such possibilities, some authors believe that LASIK should be avoided in eyes with more than 8 RK incisions. [ 18 19 ] About the advantages of PRK over LASIK, the following points are noteworthy: first: PRK avoids additive weakening of the cornea, as a risk factor of ectasia; and second: PRK does not interrupt with RK incisions, saving the remaining corneal structural integrity. [ 20 ] Corneal ectasia has occurred neither in the present study nor in our daily practice over recent years.…”

Sequential Customized Therapeutic Keratectomy in Patients With a History of Radial Keratotomy

“…Patients with reduced visual acuity and aberrations due to previous RK have been treated by photorefractive keratectomy (PRK), [21][22][23][24][25] LASIK, [26][27][28][29] corneal crosslinking, 30 deep anterior lamellar keratoplasty (DALK), 31 Bowman's layer onlay graft, 32 and corneal suturing or redeepening of the incisions. 33 Of these published studies, PRK was the most effective for overall visual acuity improvement, particularly when topography-guided procedures helped to increase surface regularity and improve predictability of results by customized ablation.…”

The Impact of Epithelial Remodeling on Surgical Techniques Used in Topography-guided Surface Ablation in Irregular Corneas

“…Unlike the current whole-eye wavefront-guided approaches, topography-guided ablation directly addresses corneal optical irregularities at their source, and is often the preferred method in therapeutic corneal refractive surgery 18,19,24. Still, suboptimal outcomes after surface ablation of irregular corneas with topography-guided PRK have been reported when mechanical or alcohol epithelial removal preceded the ablation,34,35 as in our conventional anterior topography-guided PRK (Type 1).…”