Predescemetic Deep Anterior Lamellar Keratoplasty Research Articles

Outcomes of big-bubble deep anterior lamellar keratoplasty for pediatric keratoconus.

To evaluate the outcomes and complications of deep anterior lamellar keratoplasty (DALK) performed for pediatric keratoconus. This retrospective study enrolled 44 consecutive eyes of 39 keratoconus-affected children (≤ 18years of age). All patients underwent big-bubble DALK from March 2004 to June 2016. The outcome measures included postoperative best spectacle-corrected visual acuity (BSCVA), manifest refraction, keratometry readings, and complications. The mean participant age was 16.8 ± 1.4years, and the mean follow-up period was 68.5 ± 39.9months. Successful big bubble was achieved in 33 eyes (75.0%), while the surgical technique was predescemetic DALK in 11 (25.0%). The mean BSCVA changed from 1.34 ± 0.49 LogMAR preoperatively to 0.24 ± 0.10 LogMAR postoperatively (P < 0.001). The mean keratometry decreased from 59.54 ± 5.17D preoperatively to 46.23 ± 2.17D postoperatively (P < 0.001). The complications encountered during the study period were intraoperative Descemet's membrane perforation (n = 5, 11.4%), the Urrets Zavalia syndrome (n = 1, 2.3%), graft epithelial problems (n = 3, 6.8%), subepithelial graft rejection (n = 5, 11.4%), high intraocular pressure (n = 8, 18.2%), and traumatic wound dehiscence (n = 2, 4.6%). Suture-related complications included premature loosening (n = 13, 29.6%), broken sutures (n = 12, 27.3%), suture-tract vascularization (n = 6, 13.6%), suture-associated abscesses (n = 5, 11.4%), and suture cheese wiring (n = 2, 4.6%). A clear graft was found in 40 eyes (90.9%) at the last follow-up examination. This study showed promising results with big-bubble DALK in keratoconus-affected children. A frequent and close follow-up with dedicated parental involvement is essential for the early recognition and management of postoperative complications.

Surgical Corneal Anatomy in Deep Anterior Lamellar Keratoplasty: Suggestion of New Acronyms.

Deep anterior lamellar keratoplasty (DALK) is the ideal surgery for corneal stromal diseases with a healthy endothelium. This technique offers substantial advantages compared with penetrating keratoplasty, primarily the avoidance of endothelial rejection and longer graft survival. Several DALK techniques have been described and classified into 2 categories, descemetic DALK (dDALK) and predescemetic DALK (pdDALK) depending on whether Descemet membrane-endothelium was thought to be exposed or minimal residual stroma was left behind. This classification was crucial to identify the conditions to achieve good visual outcomes with pdDALK techniques. The recent description of Dua's layer, also known as the pre-Descemet layer, has demonstrated that a very thin layer of stroma exists in some instances where Descemet membrane was thought to be completely exposed. This concept has generated a discrepancy between the previous and current applications of the terms "dDALK" and "pdDALK." We offer a summary of the published literature and a proposal for a new and more appropriate DALK nomenclature. We suggest adding the terms subtotal anterior lamellar keratoplasty (STALK) and total anterior lamellar keratoplasty (TALK).

Primary Modified Predescemetic Deep Anterior Lamellar Keratoplasty in Acute Corneal Hydrops

To report primary treatment of acute corneal hydrops (CH) with a modified technique of predescemetic deep anterior lamellar keratoplasty (pdDALK). This prospective interventional case series included 9 eyes with acute CH that underwent pdDALK as primary treatment. Technique modifications included a bevel-up needle, creating tissue emphysema as a guide for dissection, using small aliquots of air directed away from break, manual deeper dissection using a blunt dissector, centripetal dissection leaving the area of Descemet membrane (DM) break for last, retention of minimal stroma above DM tear, and tamponade of DM tear with air in the anterior chamber. In eyes with extensive area of edema or thin residual stroma, an inked trephine mark was manually deepened with a sharp crescent blade, followed by other modifications. All patients underwent uneventful surgery without enlargement of DM tear. The average follow-up period was 18 ± 13 months. All showed a clear, nonedematous graft with an area of DM defect seen and overlying cornea continuing to remain clear at final postoperative follow-up. ASOCT showed 90.8 ± 32 μm residual predescemetic host stroma on either side of the defect. CDVA improved from 0.002 ± 0.005 preoperatively to 0.35 ± 0.1 by an average of 2.3 ± 0.8 weeks and to 0.52 ± 0.13 at final postoperative follow-up. Primary pdDALK was possible as single-stage definitive treatment with early visual rehabilitation and avoidance of scarring in our case series. Simultaneous correction of pathology by closure of DM break, anatomical correction of ectasia and thinning, optical correction by improved corneal topography and by regaining corneal structure and transparency, and retention of host DM and endothelium are advantages. Advanced DALK surgeons may use this technique.

Intraoperative management of macroperforations of Descemet's membrane in deep anterior lamellar keratoplasty.

SummaryBackgroundTo describe a surgical approach for the completion of pre-descemetic deep anterior lamellar keratoplasty (pdDALK) in the presence of a macroperforation of Descemet’s membrane (DM).MethodsUsing case notes, we recorded the details of the intra- and perioperative course of patients who underwent successful pdDALK in the presence of macroperforation. A literature search of pdDALK techniques available to the corneal surgeon in a similar scenario was undertaken.ResultsIn two very different scenarios with intra- or preoperative perforation of DM, a centripetal layered lamellar dissection was performed and allowed completion of pdDALK with a residual recipient central stromal thickness of 36 and 115 µm and good visual outcome.ConclusionDespite very different scenarios, a centripetal layered lamellar dissection offers an approach for the completion of pdDALK in the presence of a macroperforation.

Early Deep Anterior Lamellar Keratoplasty (DALK) for Acanthamoeba Keratitis Poorly Responsive to Medical Treatment.

To evaluate the success (eradication of infection) or failure (recurrence of infection in the cornea or sclera, or endophthalmitis) of early therapeutic deep anterior lamellar keratoplasty (DALK) for active Acanthamoeba keratitis (AK) poorly responsive to medical treatment. Retrospective, noncomparative case series of 11 patients (11 eyes) affected by active AK poorly responsive to medical treatment who underwent early therapeutic DALK. Surgery was performed in all cases within 30 to 60 days from the onset of symptoms. Corneal ulcer depth was less than 300 μm in all cases. A 3-drug combination (chlorhexidine gluconate, propamidine isethionate, and neomycin sulfate) was the antiamoebic protocol used preoperatively and postoperatively. Cannula big bubble and "layer-by-layer" manual dissection techniques were performed. Eradication of infection, episodes of rejection, postoperative endothelial cell density, and the best spectacle-corrected visual acuity were evaluated. Histologic examination of surgical margins was performed, and margin clearance was assessed. Mean follow-up was approximately 2 years. Four descemetic DALK and 7 predescemetic DALK were performed. One small Descemet membrane rupture occurred. Peripheral surgical margins were free of infection in all cases. Deep surgical margins not free from infection were found in 2 cases. However, no episode of infection recurrence was observed. The postoperative average best spectacle-corrected visual acuity was 0.8 (range, 0.6-1.0). No case of rejection was recorded. Early therapeutic DALK could be considered a new approach to eradicate active infection in AK cases poorly responsive to medical treatment, with significant ulcer in the optical zone. Further studies are needed to validate this new indication for DALK.

Descemetic and predescemetic DALK in keratoconus patients: a clinical and confocal perspective study.

Purpose. To evaluate the clinical outcomes and in vivo confocal microscopy (IVCM) features of keratoconus patients who underwent deep anterior lamellar keratoplasty (DALK). Methods. DALK was performed using the big bubble technique in all the patients. If the bubble was not successful to bare the descemet membrane, a manual dissection layer-by layer was performed to expose a deep stromal plane close to the DM. The patients were divided in two groups depending on the intraoperative baring of the descemet membrane: predescemetic DALK (PD-DALK) and descemetic DALK (D-DALK) group. Results. One month after surgery the D-DALK patients show an increase of mean BCVA. In the PD-DALK group mean BCVA did not show significant improvement as compared to preoperative values. At 6 months after surgery mean BCVA was found to be similar in both groups. At 1 month IVCM the peak of reflectivity of the interface was lower in D-DALK group compared to PD-DALK. At 6 months the values of reflectivity were comparable. Conclusions. At 1 month D-DALK seems to lead to a minor interface reflectivity and to a better BCVA; these differences disappear after 6 months and the values of interface reflectivity and BCVA are comparable between D-DALK and PD-DALK.

Descemetic Versus Pre-Descemetic Lamellar Keratoplasty: Clinical and Confocal Study

To compare the clinical findings and confocal microscopic features of the lamellar interface after 2 types of deep anterior lamellar keratoplasty (DALK): Descemetic with total stromal resection versus pre-Descemetic with deep stromal dissection. Twenty eyes of 20 patients who had corneal disease with healthy endothelium were treated by DALK using the air technique. Baring of Descemet membrane (DM) was achieved for 12 eyes (Descemetic group). A fine stromal layer was left in 8 eyes (pre-Descemetic group). Visual acuity, interface clarity, corneal topography, confocal microscopy, and endothelial cell count were analyzed. DM microperforation occurred in 2 eyes (10%). No patient required conversion to penetrating keratoplasty (PKP) intraoperatively. Presumed stromal rejection occurred in 1 eye that was excluded from the study. In the Descemetic group, 90.9% achieved final best-corrected visual acuity (BCVA) of 20/30 or better; in the pre-Descemetic group, 75% achieved final BCVA of 20/30 or better. No statistically significant difference in mean visual outcomes was found between groups. The reflectivity of activated keratocytes at the interface was less in the Descemetic than that in the pre-Descemetic group. Ten to 12 weeks after pre-Descemetic DALK and 4 to 6 weeks after Descemetic DALK, keratocyte morphology and reflectivity had returned to normal. Mean combined topographic astigmatism was 2.17 ± 0.75 diopters (D) at 6 months (sutures out). The depth of the lamellar bed, smoothness, and healing process at the interface are the keys to optimal visual acuity. Although dissection to bare DM is more difficult, keratocyte activation and interface haze were less, but differences in final visual acuity were not significant.

Deep Anterior Lamellar Keratoplasty Using Big-Bubble Technique for Treatment of Corneal Stromal Scars

To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) in patients with anterior corneal stromal scars associated with various etiologies. A total of 79 eyes of 79 patients with corneal stromal scars sparing the Descemet membrane and the endothelium underwent DALK by using big-bubble technique. The main outcome measures of the study were the ability to successfully complete DALK, intraoperative and postoperative complications, best spectacle-corrected visual acuity, refraction, and graft clarity. Seventy-two of the surgical procedures were carried out as DALK, and the mean follow-up time was 28.1 ± 17.9 months (range, 12-78 months). The most frequent indication for DALK surgery was postherpetic keratitis (44%). Complete Descemet membrane exposure via big bubble (descemetic DALK) could be achieved in 57 cases (79%). Fifteen eyes (21%) required layer-by-layer manual dissection (predescemetic DALK). Best spectacle-corrected visual acuity of 6/12 or better was present in 59 eyes (82%) postoperatively. The mean spherical equivalent and topographic astigmatism were -3.32 ± 2.13 (range, -9.13 to +4.75) and -2.97 ± 1.94 (range, -8.0 to +4.50) diopter, respectively. There were 2 instances of stromal graft rejection, which responded to medical therapy. DALK big-bubble technique may be a valuable and safe treatment in patients with corneal stromal scar with healthy endothelium. The visual and refractive outcomes are comparable to standard penetrating keratoplasty, avoiding the risk of endothelial rejection.

Descemetic DALK and Predescemetic DALK: Outcomes in 236 Cases of Keratoconus

To report the outcomes of our experience with deep anterior lamellar keratoplasty (DALK) in patients with keratoconus. A retrospective evaluation of 236 eyes of 198 patients that have undergone DALK between 2000 and 2006 using the Tsubota, Sugita, Melles, or Anwar technique. We analyzed the frequency of true Descemet membrane exposure, which we termed dDALK, and the number of eyes in which a predescemetic plane was achieved, which we termed pdDALK. Pre- and postoperative visual acuity, endothelial cell count, and central corneal thickness were evaluated on 120 eyes followed in our department. A total of 139 of 236 (59%) eyes were classified as dDALK, with the Anwar technique showing the highest incidence of exposure of Descemet's membrane (127 of 164, 77%). Descemet ruptures occurred in 25 of 236 cases (10.5%). Three ruptures were converted to penetrating keratoplasty (PK). There was no difference in visual acuity between the pdDALK and dDALK groups at an average follow-up of 30.4 months, although the eyes in the dDALK group seemed to have faster visual recovery. Best spectacle corrected visual acuity postoperatively was at least 20/30 in 80-85% of eyes at the patient's last visit. Endothelial cell loss was 11-13%, with most of the loss occurring in the first 6 months. Performing DALK, we had the greatest likelihood of reaching Descemet's membrane with the Anwar Big Bubble technique. The visual outcomes are comparable to standard PK, avoiding the risk of endothelial rejection. Endothelial cell loss was low and the cell count was stable after 6 months.