Deep Anterior Lamellar Keratoplasty Group Research Articles

Long-term Results of Deep Anterior Lamellar versus Penetrating Keratoplasty

To compare deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in eyes with corneal diseases not involving the corneal endothelium (keratoconus, scars after infectious keratitis, stromal dystrophies, and trauma). Retrospective, comparative case series. One hundred forty-two consecutive DALK (DALK group; big-bubble technique or manual lamellar dissection using a slitlamp) and 142 matched PK (PK group). Three models were used to describe the postoperative outcomes of the endothelial cell density. A joint regression model was used to predict long-term graft survival. Visual acuity, ultrasound pachymetry, specular microscopy, and optical coherence tomography (OCT) findings were recorded. Postoperative endothelial cell loss and long-term predicted graft survival. The average 5-year postoperative endothelial cell loss was -22.3% in the DALK group and -50.1% in the PK group (P<0.0001). The early- and late-phase annual rates of endothelial cell loss were -8.3% and -3.9% per year, respectively, in the DALK group and -15.2% and -7.8% per year in the PK group (P<0.001; biphasic linear model). The median predicted graft survival was 49.0 years in the DALK group and 17.3 years in the PK group (P<0.0001). The average visual acuity was lower in the manual dissection subgroup compared with the PK group (average difference, 1.0 to 1.8 line) and with the big-bubble subgroup (average difference, 2.2 to 2.5 lines). The average central corneal thickness at 12 months was 536 μm in the PK group, 523 μm in the big-bubble subgroup, and 562 μm in the manual dissection subgroup (P<0.001). The average thickness of the residual recipient stroma measured by OCT was 87±26 μm in the manual dissection subgroup. No correlation was found between this figure and logarithm of the minimal angle of resolution at any postoperative time point (P>0.05). Long-term, model-predicted graft survival and endothelial densities are higher after DALK than after PK. The big-bubble technique gives better results than manual dissection and PK. Compared with PK, manual dissection provides higher survival of both the corneal endothelium and graft, but lower visual acuity.

Characteristic Higher-Order Aberrations of the Anterior and Posterior Corneal Surfaces in 3 Corneal Transplantation Techniques

To investigate the corneal higher-order aberrations (HOAs) of the anterior and posterior corneal surfaces in eyes that underwent penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and Descemet stripping automated endothelial keratoplasty (DSAEK). Retrospective, case-control study. study population: Twenty-four eyes underwent PK, 28 eyes underwent DALK, and 19 eyes underwent DSAEK; 29 normal eyes served as controls. observation procedures: The anterior and posterior corneal heights and pachymetric data were obtained with a Scheimpflug-based corneal topographer. Corneal HOAs for 4-mm pupils were calculated from the height data and were expanded with normalized Zernike polynomials. The HOAs resulting from the anterior and posterior corneal surfaces were compared among the procedures. main outcome measures: Anterior and posterior corneal HOAs (root mean square). Control eyes had significantly lower total HOAs and Zernike vector terms of the anterior and posterior surfaces than the other groups, except for spherical aberration. The mean anterior corneal surface total HOAs in the PK, DALK, DSAEK, and control groups were 1.38 ± 0.67 μm, 1.19 ± 0.57 μm, 0.61 ± 0.33 μm, and 0.21 ± 0.07 μm, respectively. The anterior corneal HOAs in the DSAEK group were significantly less than those in the PK group (P < .001) and DALK group (P < .001). The mean posterior corneal surface total HOAs were, respectively, 0.20 ± 0.09 μm, 0.24 ± 0.11 μm, 0.27 ± 0.15 μm, and 0.07 ± 0.02 μm. There were no significant differences in the posterior corneal HOAs among the treatment groups. Because the refractive indices between the anterior and the posterior surfaces differed greatly, eyes that undergo DSAEK have lower anterior corneal HOAs compared with PK or DALK eyes. However, the anterior and posterior corneal HOAs in DSAEK eyes still were greater than those in control eyes.

Endothelial cell loss after phacoemulsification in eyes with previous penetrating keratoplasty, previous deep anterior lamellar keratoplasty, or no previous surgery

To compare phacoemulsification-related endothelial cell loss in eyes with previous penetrating keratoplasty (PKP), previous deep anterior lamellar keratoplasty (DALK), or no previous corneal surgery. Ophthalmology Clinic, Haydarpasa Numune Education and Research Hospital, Istanbul, Turkey. Comparative case series. Eyes with previous PKP (Group 1), previous DALK (Group 2), or no previous ocular surgery (Group 3) had extracapsular cataract extraction by phacoemulsification. The endothelial cell count was evaluated 1, 3, 6, and 12 months after cataract surgery. Group 1 comprised 16 eyes and Group 2 and Group 3, 20 eyes each. The endothelial cell density (ECD) decreased progressively throughout the follow-up in all groups (P<.01). The amount of change in ECD was significantly greater in Group 1 than in Group 2 and Group 3 from preoperatively to 1 month postoperatively, from 1 to 3 months postoperatively, from 3 to 6 months postoperatively, and from 6 to 12 months postoperatively (all P<.01). The changes were similar in Group 2 and Group 3 at all time points (P>.05). Eyes with previous PKP had significantly greater endothelial cell loss than eyes with previous DALK or no previous surgery. Preservation of the patient's endothelium seems to be an advantage of DALK in terms of increasing corneal safety in future intraocular surgery. No author has a financial or proprietary interest in any material or method mentioned.

Outcomes of deep anterior lamellar keratoplasty versus intralase enabled penetrating keratoplasty in keratoconus

Objective To compare the visual and refractive outcomes after deep anterior lamellar keratoplasty (DALK) and intralase enabled keratoplasty (IEK) for keratoconus. Design A retrospective comparative case series. Participants Eighteen eyes that underwent DALK and 18 that had IEK for keratoconus. Methods Main outcome measures included preoperative and postoperative best spectacle corrected visual acuity (BSCVA), refraction, high-order aberrations (HOA), and complication rate were compared between the 2 groups after all suture removals. Results Mean time to all suture removal was 11.91 months for the DALK and 6.7 months for the IEK. The mean logMAR BSCVA of patients in the DALK group was 0.28 (20/38) and 0.37 (20/46) in the IEK group ( p < 0.211). The final sphere was −5.62 and −0.53 in the DALK and IEK groups, respectively ( p < 0.973). There was statistically significant difference in the astigmatism between the 2 groups with mean manifest cylinder of 3.13 in the DALK group and 5.78 in the IEK group ( p < 0.011).Total HOA (DALK 6.11 vs IEK 9.32, p < 0.036) and total spherical aberrations (DALK 0.44 vs IEK 0.71, p < 0.041) were both significantly higher in the IEK group. A total of 44.4% of eyes underwent astigmatic keratotomy after IEK compared to 5.6% of eyes in the DALK group ( p < 0.018; odds ratio = 13.6 [1.48, 125.31]). Overall complication rates were similar for DALK and IEK groups. Conclusions BSCVA and complication rates are similar after DALK and IEK, but each technique has its advantage. IEK offered shorter time to suture removal whereas DALK offered lower postoperative astigmatism and HOA rates.

Comparison of Macular Thickness Measured by Optical Coherence Tomography After Deep Anterior Lamellar Keratoplasty and Penetrating Keratoplasty

To compare the postoperative macular thickness changes using optical coherence tomography (OCT) in eyes that underwent deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP). Prospective, nonrandomized clinical trial. Sixty eyes of 60 patients (32 male, 28 female) with keratoconus who underwent corneal transplant surgery in an institutional setting were included in the study. Thirty eyes underwent DALK and 30 eyes underwent PKP. All eyes underwent corrected visual acuity (CVA) measurement and macular thickness measurement using spectral-domain OCT preoperatively, and 1 week, 1 month, 3 months, and 6 months postoperatively. The main outcome measures were CVA and macular thickness. The DALK group had significantly better mean CVA than that of the PKP group at 1-month (P < .001), 3-month (P = .002), and 6-month (P = .040) follow-ups. The mean macular thickness significantly increased at 1 week after PKP surgery, remained stable at 1-month follow-up, and decreased at 3- and 6-month follow-ups. On the other hand, the mean macular thickness remained stable during 6 months after DALK. Although there was no significant difference between groups preoperatively (P = .970) and at 6-month follow-up (P = .339), the PKP group had significantly higher mean macular thickness than that of the DALK group at 1-week (P < .001), 1-month (P < .001), and 3-month (P = .005) follow-ups. Although mean macular thickness increases and peaks around 1 month and returns back to normal levels at 6 months after PKP surgery, it does not change after DALK.

Comparing deep anterior lamellar keratoplasty and automated lamellar therapeutic keratoplasty in patients with keratoconus

We compared outcomes of deep anterior lamellar keratoplasty (DALK) and automated lamellar therapeutic keratoplasty (ALTK) in patients with keratoconus. Seventy eyes with keratoconus that underwent corneal transplantation using either DALK (n = 40) or ALTK (n = 30) were included in this retrospective study. DALK was performed with Anwar's big-bubble technique and ALTK using an ALTK system. Best-corrected visual acuity (BCVA), refractive results, and complications were analyzed. Mean follow-up in the DALK (16.68 ± 3.36 months) and ALTK (15.27 ± 2.50 months) groups were similar (p = 0.058). Mean final BCVA of patients in the DALK group was 0.31 ± 0.14 logarithm of the minimum angle of resolution (logMAR) and in the ALTK group 0.34 ± 0.15 logMAR, (p = 0.492). Corresponding figures for final postoperative spherical equivalents were -3.45 ± 0.77 D and -4.19 ± 0.99 D, respectively (p = 0.001). Final postoperative degree of astigmatism was similar in the two groups: DALK -4.28 ± 0.66 D; ALTK -4.50 ± 1.05 D (p = 0.307). Final visual acuity outcomes were comparable for the DALK and ALTK groups. Thus, ALTK seem to be as efficacious as DALK for surgical treatment of keratoconus.

Comparison of refractive changes after deep anterior lamellar keratoplasty and penetrating keratoplasty for keratoconus

To compare refractive changes occurring after deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PKP) in patients with keratoconus. We retrospectively reviewed the medical records of 57 patients with keratoconus who received DALK (19 eyes of 19 patients) or PKP (38 eyes of 38 patients) before and after surgery between January 1996 and January 2008, in an effort to evaluate the surgical results and clinical courses. The principal outcome measures were as follows: preoperative and postoperative uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest refraction, and corneal topography including anterior chamber depth (ACD). We noted no significant difference between the DALK and PKP groups in terms of postoperative UCVA, BCVA, astigmatism, or donor-recipient graft size disparities. For the PKP and DALK groups, the mean postoperative spheres were -1.64 D and -4.29 D at 6 months (P = 0.01) and -2.73 D and -4.22 D at 12 months, respectively (P = 0.04). Postoperative mean central corneal powers (3.0/5.0 mm zone) were 45.01/45.03 D and 46.94/47.84 D, respectively (P = 0.04 and P = 0.02). ACD after surgery was 3.25 and 3.37 mm at the final follow-up, respectively (P = 0.02). Although DALK is a safe alternative in cases of keratoconus, the DALK group evidenced significantly higher myopia than did the PKP group, which was related to steeper central corneal power and deeper ACD.

Comparison of Astigmatic Keratotomy Results in Deep Anterior Lamellar Keratoplasty and Penetrating Keratoplasty in Keratoconus

To compare astigmatic keratotomy (AK) outcomes in high astigmatism after deep anterior lamellar keratoplasty (DALK) and after penetrating keratoplasty (PK) in keratoconus patients. Prospective, comparative, interventional case series. This study comprised 20 eyes that underwent DALK and 24 eyes that underwent PK. After suture removal, all eyes had more than 5 diopters (D) of astigmatism and underwent standard manual 1-pair, 90-degree, and 90% corneal thickness AK incisions. The main outcome measures included preoperative and postoperative manifest refraction, uncorrected visual acuity, best spectacle-corrected visual acuity, surgically induced astigmatism, Orbscan II (Bausch & Lomb) corneal topography results, keratometric astigmatism, and complications. All eyes completed 6 months of follow-up. The overcorrection rate was 35% and 41.6% in the DALK and PK groups, respectively (P=.75). At 6 months after AK, logarithm of the minimal angle of resolution uncorrected visual acuity improved from 0.88 ± 0.20 to 0.54 ± 0.26 and from 1.0 ± 0.34 to 0.53 ± 0.26 in the DALK and PK groups, respectively (P=.01 to P<.01). Best spectacle-corrected visual acuity improved from 0.16 ± 0.09 to 0.13 ± 0.08 and from 0.16 ± 0.12 to 0.11 ± 0.08 in the DALK and PK groups, respectively (P=.13 to P=.01). The mean refractive cylinder was decreased 2.74 ± 1.44 D in the DALK group and 3.18 ± 2.96 D in the PK group (P=.35). Surgically induced astigmatism was 6.10 ± 3.27 D in the DALK group and 7.15 ± 2.98 D in the PK group (P=.36). The manual AK for the treatment of postkeratoplasty astigmatism after DALK and PK in keratoconus patients is a safe and effective surgical procedure, allowing similar refractive cylinder reduction and improvement in uncorrected visual acuity and best spectacle-corrected visual acuity.

Economic Evaluation of Deep Anterior Lamellar Keratoplasty Versus Penetrating Keratoplasty in The Netherlands

To evaluate the cost effectiveness of deep anterior lamellar keratoplasty (DALK) versus penetrating keratoplasty (PK) in The Netherlands. Cost-effectiveness analysis alongside a randomized, multicenter clinical trial. Fifty-three patients with corneal stromal pathologic features not affecting the endothelium were included with 28 patients in the DALK group and 25 in the PK group. Quality of life was measured before surgery and 3, 6, and 12 months after surgery. The main outcome measures were incremental cost-effectiveness ratios per clinically improved patient on the 25-item National Eye Institute Visual Functioning Questionnaire and per patient with endothelial cell loss of maximally 20% within the first year. Mean total bootstrapped costs per patient were €7607 (US$10,498) in the DALK group and €6552 (US$9042) in the PK group. The incremental cost-effectiveness ratios were €9977 (US$13,768) per clinically improved patient on the 25-item National Eye Institute Visual Functioning Questionnaire and €6900 (US$9522) per patient with cell loss of maximally 20%. In patients without perforation of the Descemet membrane, the incremental cost-effectiveness ratio was €5250 (US$7245) per patient. This study shows that DALK is more costly and more effective as compared with PK. Results on the 25-item National Eye Institute Visual Functioning Questionnaire were in favor of DALK, and endothelial cell loss in DALK patients remained stable after 6 months, whereas cell loss in PK patients continued. Furthermore, DALK procedures performed without perforation of the Descemet membrane were more effective. However, because it is unknown what society is willing to pay for an additional improved patient, cost effectiveness of DALK within a limited follow-up period of 12 months is unclear. Cost effectiveness of DALK may improve over time because of lower graft failure.

Deep Anterior Lamellar Keratoplasty as an Alternative to Penetrating Keratoplasty: A Report by the American Academy of Ophthalmology

To review the published literature on deep anterior lamellar keratoplasty (DALK) to compare DALK with penetrating keratoplasty (PK) for the outcomes of best spectacle-corrected visual acuity (BSCVA), refractive error, immune graft rejection, and graft survival. Searches of the peer-reviewed literature were conducted in the PubMed and the Cochrane Library databases. The searches were limited to citations starting in 1997, and the most recent search was in May 2009. The searches yielded 1024 citations in English-language journals. The abstracts of these articles were reviewed, and 162 articles were selected for possible clinical relevance, of which 55 were determined to be relevant to the assessment objective. Eleven DALK/PK comparative studies (level II and level III evidence) were identified that compared the results of DALK and PK procedures directly; they included 481 DALK eyes and 501 PK eyes. Of those studies reporting vision and refractive data, there was no significant difference in BSCVA between the 2 groups in 9 of the studies. There was no significant difference in spheroequivalent refraction in 6 of the studies, nor was there a significant difference in postoperative astigmatism in 9 of the studies, although the range of astigmatism was often large for both groups. Endothelial cell density (ECD) stabilized within 6 months after surgery in DALK eyes. Endothelial cell density values were higher in the DALK groups in all studies at study completion, and, in general, the ECD differences between DALK and PK groups were significant at all time points at 6 months or longer after surgery for all of the studies reporting data. On the basis of level II evidence in 1 study and level III evidence in 10 studies, DALK is equivalent to PK for the outcome measure of BSCVA, particularly if the surgical technique yields minimal residual host stromal thickness. There is no advantage to DALK for refractive error outcomes. Although improved graft survival in DALK has yet to be demonstrated, postoperative data indicate that DALK is superior to PK for preservation of ECD. Endothelial immune graft rejection cannot occur after DALK, which may simplify long-term management of DALK eyes compared with PK eyes. As an extraocular procedure, DALK has important theoretic safety advantages, and it is a good option for visual rehabilitation of corneal disease in patients whose endothelium is not compromised.

Changes in corneal biomechanics following different keratoplasty techniques

Purpose:To evaluate corneal biomechanics with the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments, Depew, NY) after penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK).Subjects and methods:Sixty-three eyes of 63 patients were included in this prospective comparative study. Patients were divided into 3 groups: the first included 21 eyes of normal subjects (control group); the second included 21 eyes with PK; the third included 21 eyes with DALK. ORA was performed 2 months postoperatively for all patients.Results:Both mean corneal hysteresis (CH) and mean corneal resistance factor (CRF) were significantly lower in the PK group than both the DALK group and matched controls. No statistically significant difference was found between mean CH and mean CRF between the DALK group and matched controlsConclusion:Corneas after PK have weaker biomechanical properties than normal corneas. DALK preserves the biomechanical strength of the corneas to almost normal values.

Penetrating keratoplasty versus deep anterior lamellar keratoplasty for the treatment of keratoconus

To compare the outcome of penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK) in the surgical management of keratoconus (KC). A retrospective review was conducted of the medical records of all patients treated with PKP or DALK for KC at University of Iowa Hospitals and Clinics from January 1, 2000, to December 31, 2006. The main outcome measures were visual outcome, graft survival, and complications. Cases with a minimum follow-up of 6 months were included in the statistical analysis. Of 41 eyes that met the inclusion criteria, 30 eyes were treated with PKP and 11 eyes were treated with DALK. The mean follow-up was almost identical for eyes treated with PKP or DALK (21.9 vs. 22.5 months, respectively). At the most recent examination, the mean best spectacle-corrected visual acuity (BSCVA) was 20/28 for the PKP group and 20/29 for the DALK group (P = 0.77). The percentage of eyes that achieved BSCVA of 20/25 or better was higher in the PKP group than in the DALK group (77.3 vs. 45.5%, respectively), but this difference was not statistically significant (P = 0.72). Endothelial rejection occurred in 4 (13.3%) eyes after PKP. Visually significant interface haze occurred in the early postoperative course in 2 (18.2%) eyes after DALK. No cases of late-onset endothelial failure were found in either group. Treatment of KC with PKP or DALK is associated with similar visual outcomes, graft survival, and prevalence of sight-threatening complications.

Endothelial Cell Loss and Visual Outcome of Deep Anterior Lamellar Keratoplasty versus Penetrating Keratoplasty: A Randomized Multicenter Clinical Trial

To compare endothelial cell (EC) loss, visual and refractive outcomes, and complications after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK). Randomized, multicenter clinical trial. Fifty-six eyes of 56 patients with a corneal stromal pathology not affecting the endothelium were randomized to DALK or PK. The DALK procedure was performed according to Anwar's big-bubble technique. Patients underwent an ophthalmic examination preoperatively and 3, 6, and 12 months postoperatively. Endothelial cell loss, refractive and topographic astigmatism, spherical equivalent, uncorrected visual acuity, and best spectacle-corrected visual acuity (BSCVA) were measured, and complications were recorded. Endothelial cell loss was significantly higher after PK compared with DALK procedures performed without perforation of Descemet's membrane (12 months: 27.7% ± 11.1% vs. 12.9% ± 17.6%). The BSCVA was significantly better in the PK group at 3 and 6 months after surgery but was not significantly different 12 months after surgery (0.39 ± 0.3 logarithm of the minimum angle of resolution [logMAR] in DALK and 0.31 ± 0.3 logMAR in PK). At 12 months postoperatively, refractive and topographic astigmatism in the DALK and PK groups were -3.37 ± 2.3 diopters (D) and -3.76 ± 2.1 D (P = 0.53), and 3.57 ± 2.3 D and 4.16 ± 2.0 D (P = 0.34), respectively. (Micro)perforation of the Descemet's membrane occurred in 32% (9/28) of the DALK eyes, and 18% (5/28) of the patients required conversion to PK. Endothelial cell loss was not significantly different between DALK and PK when cases with perforation of Descemet's membrane were included in the (intention-to-treat) analysis (12 months: 19.1 ± 21.6 vs. 27.7 ± 11.1 P = 0.112). Rejection episodes were reported in 1 patient in the DALK group (epithelial rejection) and 3 patients in the PK group (all endothelial rejections). No graft failure occurred. One year after DALK performed without perforation of Descemet's membrane, EC loss is significantly lower, whereas the BSCVA is comparable to that in the PK group. In addition, no endothelial rejection occurred in the DALK group. However, Descemet's membrane perforation remains a major complication in DALK and warrants improvements to standardize the big-bubble technique.

Cellular Changes of Donor Corneal Tissue After Deep Anterior Lamellar Keratoplasty Versus Penetrating Keratoplasty in Eyes With Keratoconus: A Confocal Study

To compare cellular changes of donor corneal tissue after deep anterior lamellar keratoplasty (DALK) with those after penetrating keratoplasty (PKP) performed in patients with keratoconus using confocal microscopy. In this nonrandomized cross-sectional comparative study, 26 eyes received DALK and 19 eyes had PKP for moderate to advanced keratoconus. A normal age-matched group consisting of 28 eyes was considered as the control. After complete suture removal, keratocyte cell density at 3 different layers (anterior, mid stroma, and posterior), corneal thickness in the 3 groups, and the features of the interface in the DALK group were evaluated with confocal microscopy. Mean participant age was 32.4 +/- 10.1, 28.5 +/- 7.5, and 32.2 +/- 6.4 years in the PKP, DALK, and normal groups, respectively (P = 0.15). Confocal microscopy was performed, on average, 24.6 +/- 3.5 months after PKP and 19.0 +/- 7.9 months after DALK (P = 0.32). The keratocyte density in the PKP group was comparable to those in the normal group in all 3 layers, whereas it was significantly reduced in the DALK group. Also, the normal reduction trend in keratocyte density from anterior to posterior stroma observed in the PKP and normal groups was not seen in the DALK group. The keratocyte density was significantly reduced, and their arrangement was profoundly altered after DALK. Such cellular changes of donor tissue after DALK can be contributed by some speculated mechanisms, including mechanical trauma to the tissue during the operation, transient dysfunction of the endothelial cells, and the presence of debris at the interface.

Deep Anterior Lamellar Keratoplasty Versus Penetrating Keratoplasty for Keratoconus: A Clinical Trial

To compare deep anterior lamellar keratoplasty (DALK) using the big-bubble technique to penetrating keratoplasty (PK) in patients with keratoconus. In this clinical trial, patients with moderate to advanced keratoconus with poor spectacle-corrected visual acuity and intolerant to contact lens wear were enrolled. DALK was performed using the big-bubble technique, and a full-thickness donor cornea without Descemet membrane was sutured to the recipient bed. PK was performed conventionally with a Hessburg-Barron suction trephine. Three types of suturing were used for both groups. Postoperative refractive errors, best-corrected visual acuity (BCVA), contrast sensitivity function (CSF), and higher order aberrations (HOAs) were compared between the study groups. The study included 81 eyes of 81 patients. Forty-six eyes underwent DALK from which 4 were excluded because of failure to achieve bared Descemet membrane. Thirty-five eyes received PK. Mean patient age was 26.91 ± 7.9 versus 30.89 ± 10.3 years in the DALK and PK groups, respectively (P = 0.06). Mean follow-up period was 22.0 ± 7.9 months in the DALK group and 24.6 ± 3.5 months in the PK group (P = 0.32). Mean postoperative spherical equivalent refractive error was -3.23 ± 3.4 diopters in the DALK group versus -2.22 ± 4.6 diopters in the PK group (P = 0.28), and mean postoperative BCVA was 0.18 ± 0.08 and 0.15 ± 0.10 logarithm of the minimum angle of resolution, respectively (P = 0.12). CSF and total aberrations and HOAs were comparable in the study groups. DALK is an effective alternative surgical procedure for patients with keratoconus; the outcomes are comparable to PK in terms of refractive errors, BCVA, CSF, and HOAs.

Comparison of Outcomes of Lamellar Keratoplasty and Penetrating Keratoplasty in Keratoconus

To compare outcomes after penetrating keratoplasty (PK) and two techniques of deep anterior lamellar keratoplasty (DALK) in patients with keratoconus. Retrospective cohort study. One hundred and twenty-five corneal transplantations comprising 100 PK and 25 DALK procedures for keratoconus at the Singapore National Eye Centre from April 1992 through December 2006 were included. DALK was performed with the modified Anwar technique (descemetic or DALKa group) in 14 eyes and manual lamellar keratoplasty (predescemetic or DALKm group) was performed in 11 eyes. At 12 months, the DALKa and PK groups achieved a logarithm of the minimum angle of resolution mean best spectacle-corrected visual acuity (BSCVA) of 0.15 and 0.27, respectively (P = .26), whereas the mean BSCVA of the DALKm group was 0.41 compared with the PK group (P = .12). Significance level was achieved between the DALKa and DALKm groups (P = .013). There was no significant difference in the mean spherical equivalent (P = .72) and astigmatism (P = .88) between the PK and DALK groups. The DALK group had a significantly lower incidence of complications compared with PK cases, including allograft rejection and glaucoma. Graft survival rate of both the PK and DALKa groups was 100%, whereas that of the DALKm group was 73% at 3 years after surgery (P = .000 between PK and DALKm groups). Visual acuity outcomes of the DALKa technique are comparable with those of PK for keratoconus, whereas DALK surgery results in fewer postoperative complications than PK. DALKa is emerging as a preferred choice among the lamellar techniques for better optical outcome. Further studies are required to provide long-term analysis of these results.

Comparison of Three Different Techniques of Corneal Transplantation for Keratoconus

To compare the visual outcomes following deep anterior lamellar keratoplasty (DALK), penetrating keratoplasty (PK), and manual top-hat PK (TH-PK) in subjects undergoing corneal transplantation for keratoconus (KC). A retrospective comparative case series. settings: Cornea clinic at the Toronto Western Hospital. study population: Fifty patients who underwent corneal transplantation for KC: 17 eyes underwent DALK, 20 eyes underwent traditional PK, and 13 had TH-PK. main outcome measures: Preoperative and postoperative uncorrected and best spectacle-corrected visual acuity (UCVA, BSCVA), high-order aberrations (HOA), complication rate, and endothelial cell counts. The median BSCVA at 12 months follow-up was 20/40 in the DALK eyes and 20/30 in the traditional PK and TH-PK eyes. The mean final spherical equivalent power in the three groups was less than -1 diopter (D). The median astigmatism was less than 3.5 D in the three groups. Complication rates were similar for three groups, although the DALK group tended toward more complications. Although DALK and TH-PK procedure results in significantly shorter time to suture removal (P < .01), they caused increased levels of HOAs (P = .02). Endothelial cell counts at 12 months were significantly higher in DALK and TH-PK eyes when compared to the traditional PK eyes (P < .001). DALK, PK, and TH-PK provide comparable visual outcomes in keratoconus patients. Although DALK and TH-PK induce more HOA, they speed up the time to suture removal and provide higher endothelial cell density at one year of follow-up.

Evaluation of Therapeutic Deep Anterior Lamellar Keratoplasty in Acute Ocular Chemical Burns

To evaluate the role of deep anterior lamellar keratoplasty (DALK) in acute ocular chemical burns. The study was conducted in 50 eyes of 50 patients (24 male, 26 female) with average age of 38.3+/-14.3 years. DALK in 5 eyes (10%), DALK with quadrant conjunctivo-limbal graft in 25 eyes (50%), and DALK with amniotic membrane in 20 eyes (40%) were performed along with conventional medical therapy. Controls who were matched in all respects (50 eyes) were given medical therapy only as they refused surgical intervention. Follow-up of cases ranged from 6 to 48 months (mean 21.5+/-14.18 months). Forty-three eyes (86%) could be restored with clear cornea as compared to 6% in control group. The visual acuity improvement was seen in 100% with good score (0.49+/-1.46) in DALK group as compared to 18% with low score (0.03+/-0.01) in control group (p<0.0001). Visual acuity improvement in DALK was 6/12 in 19 eyes (38%), 6/24 in 28 eyes (56%), and 6/36 in 3 eyes (6%) but was 3/60-6/60 in 6 eyes (12%) and finger counting only in 3 eyes (6%) in control group. Eyes with advanced grade II and grade III showed better improvement than those with burns of grade IV (p<0.05). The discomfort was relieved and epithelial healing was achieved immediately in DALK as compared to a prolonged course in control group (p<0.0001). Vascularization presented in 38% in DALK with least score (0.13+0.15) as compared to 100% in control group with high score (2.8+/-0.30). Perforation of cornea was seen only in 2 cases (4%) in DALK with low score (0.03+/-0.10) as compared to 88% in control group (1.33+/-0.20). Symblepharon was seen in 2% in DALK group as compared to 62% in control group. DALK with and without conjunctival or amniotic membrane transplantation is an effective technique in restoring the integrity of the eye with an excellent graft transparency in 86% and improvement in visual acuity in 100% of the acute chemical burns.

Comparison of Deep Anterior Lamellar Keratoplasty and Penetrating Keratoplasty for Keratoconus

Purpose: To compare the therapeutic outcomes after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) in patients with keratoconus. Methods: We retrospectively reviewed the clinical records of 57 patients diagnosed with keratoconus who had undergone DALK (19 eyes of 19 patients) and PKP (38 eyes of 38 patients) in Samsung medical center between January 1995 and January 2006. Results: The 19 and 38 patients with keratoconus who underwent DALK and PKP had mean ages of 25.3 (range: 17-46) and 26.2 (range: 12-51) years, respectively. These groups were followed up for mean times of 16.7 (range: 6-34) and 45.7 (range: 6-115) months after surgery, respectively. The DALK group showed significantly higher values of refractive power, central corneal thickness, and endothelial cell density, while two eyes (10.5%) in the DALK group developed stromal rejection, which resolved after steroid therapy. In the PKP group, eight eyes (21%) developed endothelial rejection, among whom one eye (2.6%) resulted in a graft failure of a patient who underwent re-PKP, and two eyes (5.3%) in the PKP group developed secondary glaucoma. Conclusions: DALK should be considered as the primary surgical technique in keratoconus, because the visual outcome is comparable with PKP and it reduces severe complications such as secondary glaucoma and the risk of graft failure by preserving the corneal endothelium compared to PKP.

Résultats de la kératoplastie lamellaire profonde pré-descemétique dans la prise en charge du kératocône chirurgical, en comparaison avec la kératoplastie transfixiante

To determine the advantages, safety, and accuracy of deep anterior lamellar keratoplasty (DLK) versus penetrating keratoplasty (PK) in terms of visual acuity, astigmatism, and endothelial preservation in corneal diseases with healthy endothelium. Of these candidates for keratoplasty, the study investigated keratoconus patients with no other ophthalmic abnormalities. This comparative nonrandomized retrospective study investigated 22 patients with keratoconus requiring surgery, who underwent keratoplasty in the Nantes University Hospital between 1 June 2002 and 1 January 2004. Ten DLK, ten PK and two PK converted DLK cases were analyzed. Follow-up at 2 weeks and at 3, 6, 9, and 18 months is reported for visual acuity, astigmatism, pachymetry, specular microscopy, and intraocular pressure (IOP). Data are compared before and after surgery at each follow-up date. Preoperative visual acuity improved in both groups from 0.14+/-0.13 to 0.8+/-0.17 postoperatively. There was no significant difference between the two groups before and at each time after surgery for visual acuity and astigmatism (3.5+/-2 diopters in the PK group and 3+/-0.9 D in the DLK group). There was a statistical difference for IOP with two occurrences of increased IOP up to 30 mmHg in the PK group. Endothelial cell count analysis showed an immediate postoperative decrease of 10% in the DLK group (versus approximately 40% in the PK group), remaining rather stable the 1st year (-3.3%), although cell loss in the PK group declined up to 10% more at 18 months. With no statistical difference between the two groups for visual acuity and astigmatism, DLK is effective. It is safer than PK in terms of IOP disturbance (leading cause of graft failure) and endothelial cell loss. DLK converted into PK (16%) showed the same profile as first-intention PK. Despite very similar effectiveness, DLK in keratoconus surgery should be proposed rather than PK because it appears safer not only in the short term but also probably in the long term, with no risk of endothelial cell rejection.