Deep anterior lamellar keratoplasty for keratectasia after laser in situ keratomileusis

ARTICLE

Deep anterior lamellar keratoplasty for keratectasia after laser in situ keratomileusis Ramin Salouti, MD, Mohammad H. Nowroozzadeh, MD, Payam Makateb, MD, Mohammad Zamani, MD, Maryam Ghoreyshi, MD, Gerrit R.J. Melles, MD, PhD

PURPOSE: To assess the efficacy of deep anterior lamellar keratoplasty (DALK) for treating postLASIK keratectasia. SETTING: Poostchi Eye Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. DESIGN: Retrospective interventional cases series. METHODS: The same surgeon performed all DALK procedures using the Melles manual technique. The preoperative and postoperative corrected distance visual acuity (CDVA), spherical equivalent (SE) refraction, keratometry (K) readings, and endothelial cell profiles were compared. RESULTS: The cohort comprised 20 eyes of 18 patients (72% women) with a mean age of 29 years G 4 (SD). The mean follow-up was 31.8 G 17.0 months (range 6 to 60 months). The mean Snellen CDVA improved significantly from 20/191 before DALK to 20/23 after DALK (P < .001). The mean of the modulus of SE refraction was 11.9 G 6.6 diopters (D) and 11.4 G 4.3 D, respectively (P Z .446). The mean K value was 52.2 G 7.0 D before DALK and 46.0 G 1.9 D after DALK (P Z .001); the mean apical K value, 59.5 G 5.1 D and 49.9 G 2.8 D, respectively (P < .001); and the mean keratometric astigmatism, 4.3 G 2.4 D and 1.9 G 1.2 D, respectively (P Z .003). The endothelial cell profile did not change significantly, and no major complications related to DALK occurred. Twelve eyes had additional refractive procedures to correct residual ametropia. CONCLUSION: Deep anterior lamellar keratoplasty using the Melles manual technique was effective and safe in restoring CDVA in patients with post-LASIK keratectasia; however, high residual ametropia was a common finding. Financial Disclosure: Dr. Melles is a consultant to D.O.R.C. International/Dutch Ophthalmic USA. No author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2014; 40:2011–2018 Q 2014 ASCRS and ESCRS

Corneal ectasia after laser in situ keratomileusis (LASIK) refers to postoperative progressive stromal thinning and anterior and posterior corneal steepening that leads to progressive increases in myopia, irregular astigmatism, visual distortion, and loss of corrected distance visual acuity (CDVA).1,2 Excimer laser surgery is a subtractive corneal procedure that violates the structural stability of the cornea and induces postoperative corneal weakening, which can lead to keratectasia in susceptible patients.1,3 Risk factors for this complication include subnormal tensile strength of the cornea (eg, undiagnosed forme fruste Q 2014 ASCRS and ESCRS Published by Elsevier Inc.

keratoconus), low residual stromal bed thickness, and multiple enhancement procedures.4 Based on the severity of the condition, spectacles, rigid gas-permeable (RGP) contact lenses,5 and surgical interventions such as riboflavin and ultraviolet-A collagen crosslinking,6 corneal flap suturing,7 and intrastromal corneal ring segment implantation8,9 have been put to promising use. Until recently, penetrating keratoplasty (PKP)10,11 was the only definitive treatment for post-LASIK ectasia; however, because of potential serious complications, such as endothelial graft rejection, it was reserved for the most advanced cases. http://dx.doi.org/10.1016/j.jcrs.2014.04.029 0886-3350

2011

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DALK FOR POST-LASIK KERATECTASIA

Deep anterior lamellar keratoplasty (DALK), a partial-thickness graft that preserves the host endothelium and Descemet membrane, was introduced and has been used successfully as an alternate approach to treating corneal ectatic disorders and anterior corneal opacities.12,13 Although interface haze and irregularities have generated concern about the visual outcomes of this procedure, it has the major advantage of leaving the healthy endothelial cells in place, thus avoiding endothelial graft rejection. There are few reports of the use of DALK for the treatment of post-LASIK ectasia.14–16 In 2 of them14,15 (total of 7 eyes), DALK with the Melles manual technique was used, whereas in the other study16 (11 eyes), the Anwar big-bubble technique was used. Although seemingly promising, the small cohorts, particularly in the studies using the Melles manual technique, prohibit valid intragroup statistical analysis of the visual and topographic outcomes. In the present study, we evaluated the outcomes of DALK with the Melles manual technique for the treatment of post-LASIK ectasia in a larger cohort with long-term follow-up in some cases. PATIENTS AND METHODS In this interventional case series, the medical charts of patients who had DALK for post-LASIK ectasia were retrospectively reviewed. Post-LASIK keratectasia was defined as a progressive decrease in visual acuity; the regression of myopia, astigmatism, or both after successful LASIK; and topographic changes indicating ectasia, including irregular astigmatism and inferior corneal steepening. Indications for DALK were poor CDVA, RGP contact lens intolerance, or inappropriate contact lens fit. The Ethics Committee, Shiraz University of Medical Sciences, approved the study protocol.

Measurements A complete ophthalmic evaluation, including Snellen CDVA, slitlamp biomicroscopy, tonometry, dilated fundus

Submitted: October 18, 2013. Final revision submitted: March 20, 2014. Accepted: April 7, 2014. From Poostchi Ophthalmology Research Center (Salouti, Nowroozzadeh, Makateb, Ghoreyshi), Shiraz University of Medical Sciences, and Salouti Eye Research Center (Salouti, Zamani, Ghoreyshi), Salouti Eye Clinic, Shiraz, Iran; the Netherlands Institute for Innovative Ocular Surgery (Melles), Rotterdam, the Netherlands. Supported by Shiraz University of Medical Sciences (grant 2562). Corresponding author: Maryam Ghoreyshi, MD, Department of Ophthalmology, Poostchi Ophthalmology Research Center, Poostchi Clinic, Zand Street, Shiraz, Iran. E-mail: ghoreyshimaryam@ gmail.com.

examination, manifest refraction, and corneal topography, was performed before surgery. The central corneal thickness (CCT) and corneal endothelium were evaluated using a noncontact autofocus specular microscope (Topcon SP2000p, Topcon Corp.).17 Follow-up examinations were performed 3, 6, and 12 months after DALK as well as every 12 months thereafter. The postoperative assessment comprised CDVA, manifest refraction, tonometry, corneal topography, and specular microscopy. Intraoperative and postoperative complications were recorded. When additional surgical interventions such as phakic intraocular lens (pIOL) implantation were required, the results before the intervention were used in the analysis. The main outcome measures were CDVA, spherical equivalent (SE) refraction, and keratometric astigmatism. Secondary outcome measures included mean keratometry (K) values, apical K values, CCT, endothelial cell density, mean cell area, the standard deviation of the mean cell area, and the coefficient of variation of the cell area.

Surgical Technique The same experienced anterior segment surgeon (R.S.) performed all DALK procedures using general anesthesia and a technique reported by Melles et al.18 In brief, after a localized peritomy was performed 1.0 mm behind the superior limbus, a 5.0 mm incision (350 mm depth) was created with a diamond knife. The aqueous humor was replaced with air through a self-sealing side port to help the surgeon gauge the depth of the corneal lamellar dissection. The corneal dissection was initially made with a diamond crescent knife; subsequently, deep dissection was continued with a deep lamellar corneal dissector (#6-607, Duckworth & Kent). Next, the scleral tunnel was sutured with 10-0 nylon and the corneal pocket filled with an ophthalmic viscosurgical device. Then, the cornea was trephined with a HessburgBarron suction trephine and the Descemet membrane was bared using curved microscissors. Human cadaver donor eyes stored in cold-storage medium (Optisol) were obtained from the central eye bank of Iran. An 8.00 to 8.75 mm trephine was used to punch a 0.25 mm oversized donor button. The Descemet membrane with endothelium was gently stripped from the donor button using a cellulose sponge and a fine forceps. The donor button was sutured to the recipient stromal bed with 8 interrupted sutures and 2 rows of no-torque running 10-0 nylon sutures (Sharpoint, Angiotech).17 After surgery, patients were instructed to instill topical prednisolone acetate 1.0% 4 times daily during the first 2 weeks after surgery followed by a weekly tapering dose over the next 2 weeks. Subsequently, the patients received fluorometholone acetate 0.1% or loteprednol etabonate 0.5% 2 times daily for the next 3 months and then once daily thereafter until 12 months postoperatively. Topical chloramphenicol 0.5% was used 4 times daily during the first postoperative week, and topical lubricants were used as needed for several months. To account for surgery-induced corneal astigmatism, the interrupted sutures on the steep meridian (determined by corneal topography) were removed at the 3-month followup examination. Loose sutures or sutures with associated abscesses were removed on diagnosis. The running sutures were left in place until 18 to 24 months after surgery, when all sutures were removed.

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DALK FOR POST-LASIK KERATECTASIA

Statistical Analyses

Table 1. Patient data before LASIK.

Data were analyzed using SPSS software (version 17, SPSS, Inc.). The Wilcoxon signed-rank test was used to test the difference between measurements obtained before DALK and those obtained after DALK. The CDVA data were converted to logMAR values for statistical analysis. Because the post-LASIK keratectasia was asymmetric in the fellow eyes of the 2 patients with bilateral surgery, each eye was regarded as a separate identity in the analysis. A P value less than 0.05 was considered statistically significant.

RESULTS Data from 20 eyes of 18 patients were analyzed. Unilateral DALK was performed in 16 patients and bilateral DALK in 2 patients. The mean age of the patients at the time of DALK was 29 years G 4 (SD) (median 29 years; range 20 to 38 years), and 13 patients (72%) were women. The mean follow-up after DALK was 31.8 G 17.0 months (median 36 months; range 6 to 60 months). Table 1 shows the pre-LASIK data, which were available for 14 patients. Table 2 shows the pre-DALK and post-DALK measurements by individual patient. For the 14 patients (16 eyes) who had complete data, the mean of the modulus of SE refraction was 6.8 G 1.7 diopters (D) (median 6.8 D; range 4.5 to 10.5 D) before LASIK, 12.5 G 6.1 D (median 13.5 D; range 2.5 to 24.3 D) before DALK, and 11.2 G 4.0 D (median 11.6 D; range 3.3 to 17.3 D) after DALK (P Z .004, Friedman test) (P Z .004 for pre-LASIK versus preDALK, P Z .001 for pre-LASIK versus post-DALK, and P Z .187 for pre-DALK versus post-DALK; Wilcoxon signed-rank test). The mean K value in the 10 eyes with complete data was 43.6 G 1.1 D (median 43.7 D; range 42.4 to 46.1 D) before LASIK, 52.9 G 4.7 D (median 52.9 D; range 44.0 to 62.3 D) before DALK, and 45.5 G 2.1 D (median 44.8 D; range 43.6 to 49.1 D) after DALK (P ! .001, Friedman test) (P Z .005 for pre-LASIK versus pre-DALK, P Z .074 for pre-LASIK versus post-DALK, and P Z .005 for pre-DALK versus post-DALK; Wilcoxon signed-rank test). Table 3 shows the differences in SE refraction and mean K values between post-DALK measurements and pre-LASIK measurements in the 10 eyes. Table 4 shows a comparison of measurements before DALK and after DALK. There was a statistically significant improvement in Snellen CDVA from 20/191 before DALK to 20/23 after DALK (and after additional corrective procedures) (P ! .001). The corneal contour was significantly improved after DALK (Figure 1). The mean K, apical K, and keratometric astigmatism values decreased significantly after DALK. The change in the mean of the modulus of SE refraction was not statistically significant (P Z .446). At the last follow-up examination after DALK, the residual ametropia was 3.0 D

Pt 1 2 3 4 5 6* 7 8 9 10 11 12 13 13 14 14

Eye L R R L R L R R R L R L R L R L

Manifest Refraction (D)
7.00
1.75  120
4.00
0.75  179
6.75
4.50  60
5.00
5.00  170
4.50
1.50  5
6.75
1.75  114
6.50 C8.00
2.00  170 C7.75
0.50  160
3.50
2.5  10
4.50
3.00  5
6.00
1.00  NA
4.00
1.50  90
4.50
1.50  130
6.00
3.00  8
9.00
3.00  178

Mean K (D)

CCT (mm)

42.55 43 44.4 43.96 43.96 43.5 42.54 46.05 44.00 42.38 NA NA NA NA NA NA

506 544 571 524 519 507 524 541 550 510 566 NA 475 496 NA NA

CCT Z central corneal thickness; K Z keratometry; NA Z not available; Pt Z patient *Had enhancement procedure (laser in site keratomileusis)

or more in all eyes, 5.0 D or more in 17 eyes (85%), and 10.0 D or more in 15 eyes (75%). The endothelial cell measurements did not significantly change after DALK. There were no significant intraoperative complications (eg, Descemet membrane perforation) or postoperative complications (eg, ocular hypertension, rejection, Urrets-Zavalia syndrome). Postoperatively, 12 eyes had additional procedures for high residual ametropia or astigmatism; none of these eyes had a major intraoperative complication (Table 5). DISCUSSION This study evaluated the outcomes of DALK with the Melles technique in a cohort of patients with postLASIK ectasia. At the last follow-up examination, all eyes had a CDVA of 20/30 or better. The mean K, apical K, and keratometric astigmatism values were all significantly lower after surgery. However, the modulus of SE refraction did not change significantly after DALK and was substantial in most patients. Table 6 shows findings in previous studies of DALK for post-LASIK ectasia.14–16 Overall, the outcomes were favorable and the CDVA was remarkably improved postoperatively in all the studies. In the study by Javadi and Feizi,16 the difference in CDVA was statistically significant (P Z .007). Other studies did not have a sufficient sample size for statistical analysis.14,15 Altogether, DALK seems to be effective in improving CDVA in patients with post-LASIK ectasia. Despite the improvement in the CDVA, high residual myopia has been a consistent finding after DALK

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DALK FOR POST-LASIK KERATECTASIA

Table 2. Patient data before and after DALK by patient. Before DALK

After DALK

Pt

Eye

Corneal Suture

FU (Mo)

CDVA

SE (D)

K Value (D)

CDVA*

SE (D)†

K Value (D)†

1 2 3 4 5 6 7 8 9 10 11 12 13 13 14 14 15 16 17 18

L R R L R L L R R L R L R L R L R L L L

Out Out Out Out Out In place In place In place In place Out Out Out Out Out Out Out Out In place Out Out

36 24 48 48 36 6 12 12 12 36 24 24 60 48 48 36 60 6 36 24

20/200 20/100 20/100 20/70 CF at 1.5 m CF at 3 m 20/70 20/70 20/100 20/200 CF at 5 m 20/200 CF at 1 m CF at 4 m 20/100 20/70 CF at 3 m 20/100 20/200 CF at 3 m


15.75
7.00
16.13
16.00
14.25
11.75
20.50 NA C3.25
13.50
16.75
2.50
9.00
9.75
7.75
24.25
7.50
11.25
7.00
13.00

60.0/64.5 42.0/46.0 47.9/50.1 50.9/55.0 52.3/59.4 49.3/57.1 49.4/55.5 52.1/58.5 51.9/53.9 49.7/51.9 48.9/52.3 40.0/42.0 50.6/55.0 46.7/50.9 45.5/49.3 57.7/60.8 48.9/52.5 46.8/49.4 67.2/78.4 43.3/45.3

20/30 20/30z 20/25z 20/20z 20/20z 20/20 20/30 20/20z 20/20z 20/25 20/20z 20/20z 20/25 20/20 20/20z 20/20z 20/20 20/30 20/30z 20/20


13.50
9.00
11.50
12.25
11.25
11.75
15.25 C12.00 C7.13
10.50
17.25
14.50
3.25
3.50
11.50
15.50
3.50
16.63
10.63
17.00

46.2/50.9 42.1/45.0 42.9/46.9 45.2/47.7 43.2/44.1 46.5/47.7 48.6/49.5 43.3/43.8 43.6/44.2 43.3/46.1 47.3/49.9 44.5/47.6 45.2/45.4 44.7/45.1 46.4/48.8 47.2/48.7 44.0/45.1 45.1/47.4 44.9/46.0 47.3/49.5

CDVA Z corrected distance visual acuity (spectacles); CF Z counting fingers; DALK Z deep anterior lamellar keratoplasty; FU Z follow-up; Pt Z patient; SE Z spherical equivalent refraction *At last follow-up examination after any enhancement procedures (eg, phakic intraocular lens implantation) † At last follow-up examination after deep anterior lamellar keratoplasty before additional corrective procedures (eg, phakic intraocular lens implantation) z Had additional procedures for refractive correction after DALK (see Table 5)

for post-LASIK ectasia14–16 as well as after PKP.19,20 Javadi and Feizi16 postulate that a long axial length (AL) in myopic eyes having LASIK constitutes a major factor for the recurrence of myopia after DALK, which Table 3. Differences in post-DALK and pre-LASIK SE refraction and mean K measurements by patient. Post-DALK*
Pre-LASIK Pt

Pre-LASIK SE (D)

SE (D)

Mean K (D)

1 2 3 4 5 6 7 8 9 10


8.0
4.5
9.0
7.5
5.3
7.8
6.5 C7.0 C7.5
4.8


5.6
4.5
2.5
4.8
6.0
4.0
8.8 C5.0
0.38
5.8

6.1 0.6 0.5 2.5
0.3 3.6 6.5
2.5
0.1 2.3

DALK Z deep anterior lamellar keratoplasty; K Z keratometry; LASIK Z laser in situ keratomileusis; Pt Z patient; SE Z spherical equivalent refraction *Before any additional corrective procedure (eg, phakic intraocular lens implantation)

replaces the flattened cornea with a donor lenticule that has a normal curvature. They also state that the recipient–donor trephine size disparity might also contribute to the observed refractive surprise. Similarly, in our series, the post-DALK SE refraction reflected the pre-LASIK SE refraction (ie, hyperopic eyes remained hyperopic and myopic eyes remained myopic), confirming that pre-LASIK ametropia is the major determinant in post-DALK ametropia. However, the degree of post-DALK ametropia was considerably greater than that observed before LASIK and comparable to that of ectatic corneas before DALK. This finding was observed despite the use of an oversized donor lenticule (0.25 mm) in all cases. In our study, other than patients 9 and 13 (who had relatively comparable pre-LASIK and post-DALK SE refractions), all patients with available data had a remarkable increase in ametropia. Table 3 confirms that changes in K values alone do not explain the changes in SE in all patients. Together, these observations imply that factors other than AL, K values, and recipient–donor trephine size disparities (which primarily affect keratometry) contribute to high ametropia after DALK. We postulate that the peripheral corneal changes in post-LASIK ectasia, along with the

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DALK FOR POST-LASIK KERATECTASIA

Table 4. Comparison of mean pre-DALK and mean post-DALK measurements in all cases with post-LASIK keratectasia. Parameter Snellen CDVA* Mean G SD Median Range LogMAR CDVA Mean G SD Median Range Spherical equivalent (D)z Mean G SD Median Range Mean keratometry (D) Mean G SD Median Range Keratometric astigmatism (D) Mean G SD Median Range Apical keratometry (D) Mean G SD Median Range CCT (mm) Mean G SD Median Range ECD (cells/mm2) Mean G SD Median Range MCA (mm2) Mean G SD Median Range SDMCA Mean G SD Median Range CoV Mean G SD Median Range

Before DALK After DALK

P Value

20/191 20/200 20/1200, 20/70

20/23 20/20 20/30, 20/20†

d

0.98 G 0.39 1.00 0.54, 1.77

0.06 G 0.08 0.00 0.00, 0.17†

!.001

11.9 G 5.6 11.8 2.5, 24.3

11.4 G 4.3 11.6 3.3, 17.3x

.446

52.2 G 7.0 51.6 41.0, 72.8

46.0 G 1.9 45.8 43.6, 49.1x

.001

4.3 G 2.4 3.9 2.0, 11.2

1.9 G 1.2 1.9 0.2, 4.7x

.003

59.5 G 5.1 59.3 50.6, 68.4

49.9 G 2.8 49.5 44.9, 55.0x

!.001

444 G 58 426 343, 554

553 G 37 559 477, 620x

.001

2510 G 421 2557 1483, 3187

2594 G 315 2608 2099, 3037x

.744

406 G 90 386 312, 674

391 G 57 387 329, 476x

.647

141 G 37 139 73, 229

127 G 38 123 64, 217x

.124

34 G 9 33 23, 60

33 G 7 34 16, 46x

.602

CDVA Z corrected distance visual acuity (spectacles); CCT Z central corneal thickness; CoV Z coefficient of variation in mean cell area; DALK Z deep anterior lamellar keratoplasty; ECD Z endothelial cell density; MCA Z mean cell area; SDMCA Z standard deviation of MCA *Mean Snellen corrected distance visual acuity was retrieved by converting from the mean logMAR corrected distance visual acuity; thus, no standard deviation or P value provided. † At last follow-up examination after any additional corrective procedures (eg, phakic intraocular lens implantation) z Cohort included myopic and hyperopic eyes; thus, the modulus of spherical equivalent refraction was used as index for the magnitude of overall ametropia. x At last follow-up examination before any additional corrective procedures (eg, phakic intraocular lens implantation)

Figure 1. The pre-DALK (A) and post-DALK (B) Scheimpflug images of a patient with post-LASIK keratectasia. Note the normalization of the corneal contour after DALK, particularly on the endothelial side.

resulting alterations in the anterior chamber depth and nodal points of the eye, or the effect of the posterior corneal curvature, which is generally less affected than the anterior corneal curvature by DALK, may also have a role in post-DALK refractive surprises in eyes that develop ectasia after LASIK. The evaluation of these issues was beyond the aim of the present study and should be addressed in future studies. In the study by Javadi and Feizi,16 DALK did not alter the mean K or keratometric astigmatism values. In contrast, both parameters improved in our study. Although the post-DALK mean K measurements were comparable in the 2 studies (46.0 D in ours and 46.3 D in Javadi and Feizi), the pre-DALK readings were considerably higher in our study (52.2 D versus

Table 5. Patient data after secondary procedure. Pt

Eye

Secondary Procedure

2 3 4 5 6 8* 9* 11 12 14 14 17

R R L R L R R R L R L L

pIOL implantation pIOL implantation pIOL implantation pIOL implantation pIOL implantation RLE C IOL implantation RLE C IOL implantation pIOL implantation pIOL implantation C AK pIOL implantation pIOL implantation pIOL implantation

Manifest Refraction (D) Plano
0.75  160 Plano
1.0  180 Plano
1.25  60 Plano
2.75  180 C2.00
3.00  115 Plano
1.25  10 C0.75
1.50  60 Plano
1.25  60 Plano
5.00  90 Plano
1.25  55 Plano
2.25  50 Plano
1.00  90

AK Z arcuate keratotomy; IOL Z intraocular lens; pIOL Z phakic intraocular lens (nontoric iris fixated); Plano Z spherical refraction within G0.50 D; Pt Z patient; RLE Z refractive lens exchange *Suture removal performed at time of pIOL implantation

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Table 6. Results in previous studies of DALK for post-LASIK ectasia compared with results in the present study. Parameter Publication year Patients/eyes (n) Age (y) Mean G SD Range DALK method Follow-up (mo) Mean G SD Range Pre-LASIK SE (D) Mean G SD Range Pre-DALK CDVA Mean G SD Range SE (D) Mean G SD Range Km (D) Mean G SD Range Ka (D) Mean G SD Range Post-DALK CDVA Mean G SD Range SE (D) Mean G SD Range Km (D) Mean G SD Range Ka (D) Mean G SD Range Complications

Javadi and Feizi16

Villarrubia et al.14

McAllum et al.15

Present Study

2010 10/11

2007 4/5

2007 2/2 Case 1: NR; Case 2: 48

2014 18/20

32 G 7 25, 49 Big bubble

32 G 5 28, 40 Manual dissection

20.2 G 6.6 13, 30

14.4 G 6.9 6, 24


5.8 G 3.2
8.4,
1.8*


9.2 G 4.1
14.3,
5.0

Manual dissection Case 1: 24; Case 2: 6

29 G 4 20, 38 Manual dissection 31.8 G 17.0 6, 60

Case 1:
4.5; Case 2:
10.6

6.8 G 1.7k 4.5, 10.5

Case 1: 20/60C2†; Case 2: 20/200 20/160 CF 0.5 m, 20/40

20/125 20/200, 20/80


11.5 G 5.4
3.0,
21.0


12.9 G 6.2
7.0,
21.0

20/191 20/1200, 20/70 Case 1:
3.38; Case 2: 0.1

11.9 G 5.6k 2.5, 24.3

Case 1: 47.7; Case 2: 48.4 46.8 G 7.2 40.0, 65.0

NR NR

4.8 G 2.6 0.0, 9.8

NR NR

Case 1: 2.2; Case 2: 8.1

52.2 G 7.0 41.0, 72.8 4.3 G 2.4 2.0, 11.2

Case 1: 20/40C2z; Case 2: 20/40Cx 20/40 20/80, 20/20

20/29 20/40, 20/20


13.5 G 10.5
2.0,
31.0


7.1 G 5.7
1.5,
13.5

46.3 G 1.9 43.3, 49.3

NR NR

4.6 G 2.5 0.5, 8.5 None

NR NR None

20/23{ 20/30, 20/20 Case 1:
2.8; Case 2:
12.0 11.4 G 4.3k,# 3.3, 17.3 Case 1: 45.0; Case 2: NR 46.0 G 1.9 43.6, 49.1 Case 1: 1.9; Case 2: NR

None

1.9 G 1.2 0.2, 4.7 None

CDVA Z corrected distance visual acuity; CF Z counting fingers; DALK Z deep anterior lamellar keratoplasty; Ka Z keratometric astigmatism; Km Z mean keratometry; Manual dissection Z manual dissection using Melles technique; NR Z not reported; SE Z spherical equivalent refraction *Data were available for 6 patients. † Patient was pseudophakic and had posterior capsule opacity. z Laser posterior capsulotomy was also performed after DALK. x Data reported were from last follow-up after DALK but before additional corrective surgery. k Because the cohort included both myopic and hyperopic eyes, the modulus of SE was used as an index for the magnitude of overall ametropia. { Data reported were from last follow-up after additional corrective procedures such as phakic intraocular lens implantation. # Data reported were from last follow-up before additional corrective procedures such as phakic intraocular lens implantation.

46.8 D). This implies that the differences in the postDALK changes in mean K values between the 2 studies are rooted in the dissimilar preoperative characteristics of the cohorts rather than in the surgical technique. The final keratometric astigmatism was lower in our

series (1.9 D versus 4.6 D); this difference could be attributed to the differing DALK techniques, suturing (or suture removal) practices, or the duration of follow-up. The mean follow-up was 31.8 months in our series and 20.2 months in the study by Javadi

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and Feizi. Also, the sutures were completely removed in 15 eyes in our study. In the present study, the pre-DALK and post-DALK endothelial profile measurements were almost the same. Although a decrease in the actual number of endothelial cells as a result of surgical trauma was expected, the measurement may not show these differences because of reproducibility limitations of the measurement device or postoperative changes in corneal curvature, as described after DALK in eyes with keratoconus.17 The present study had the largest cohort to date of eyes in which DALK was performed for post-LASIK ectasia. In addition, previous studies evaluated DALK in myopic eyes that had been myopic before the procedure; our cohort included 2 cases (# 8 and #9) of hyperopic LASIK. The major limitation of this study was its lack of a parallel group, which could have been treated with classic PKP. Further studies to compare DALK and other standard treatments for post-LASIK ectasia are warranted. In conclusion, our study confirmed that DALK is effective and safe in restoring CDVA in patients with post-LASIK ectasia, although the refractive outcomes were fair. Many patients were dissatisfied with the final refractive outcome and requested further refractive surgery. Our experience with pIOL implantation was successful, and the patient satisfaction was improved significantly after the additional corrective procedure. In these cases, a thorough consultation is mandatory; patients should be informed that the DALK will improve their CDVA but most likely not their refractive errors and that they may require additional postoperative optical correction or surgical intervention to correct high ametropia. WHAT WAS KNOWN  For most severe cases of post-LASIK ectasia, PKP is the only definitive treatment; however, serious potential complications (in particular, endothelial graft rejection) exist.  Deep anterior lamellar keratoplasty has been used to avoid the complications of PKP. WHAT THIS PAPER ADDS  Results support using DALK instead of PKP as a treatment for advanced post-LASIK ectasia to eliminate the risk for corneal endothelial rejection.  In general, the refractive outcomes after DALK for postLASIK ectasia were poor. Many patients were dissatisfied with the final refractive outcome and requested further refractive surgery (eg, pIOL implantation).

2017

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First author: Ramin Salouti, MD Poostchi Ophthalmology Research Center, Shiraz, Iran