Technique Of Deep Anterior Lamellar Keratoplasty Research Articles

Sarnicola Air–Visco Bubble Technique in Deep Anterior Lamellar Keratoplasty

The purpose of this study was to describe a new modification for big-bubble deep anterior lamellar keratoplasty (DALK) using pneumatic pressure to detach Descemet membrane (DM) via air injection followed by ophthalmic viscoelastic device (OVD) injection. After failure of big-bubble formation after air injection, OVD was injected from a different site other than the previous air injection using a 27-gauge cannula to detach DM, called air-visco bubble (AVB) DALK technique. The technique was used in 7 human corneoscleral rims that were investigated with anterior segment optical coherence tomography and histopathology and in 69 eyes that underwent DALK surgeries. Big-bubble formation was noted in 4 of 7 of the donor corneoscleral rims. The anterior segment optical coherence tomography showed big-bubble formations together with intrastromal OVD accumulation. The histology of the donor corneas showed microdetachments at the DM in the periphery, deep intrastromal separation, and big-bubble formation filled with OVD. One hundred forty-one of 210 eyes (67%) underwent successful DALK with only air injection, and 69 of 210 eyes (33%) underwent AVB technique when a big bubble was not achieved with only air injection. All the corneas showed a clear interface with good wound healing when DM was bared with the AVB DALK technique. Additional OVD injection to detach DM may be useful in cases where air injection fails. Also, creating small DM detachments with air injection may facilitate the formation of a big bubble with further OVD injection.

Light microscopic evaluation and scanning electron microscopic analysis of horse eyes following deep anterior lamellar keratectomy

OBJECTIVE To describe the technique of deep anterior lamellar keratoplasty (DALK) with Descemet's membrane (DM) exposure in horse eyes. Also, to compare the efficacy and safety of viscodissection and big-bubble techniques for DALK. ANIMALS STUDIED Thirty-four ex vivo horse eyes. PROCEDURE Deep anterior lamellar keratoplasty was performed in 34 ex vivo horse eyes. Two groups (Group V--viscodissection--2% sodium hyaluronate; Group A--air--big-bubble) of 17 eyes were studied. Other than the substance used, the surgical technique was similar for both groups. Nonperforated eyes were submitted for light microscopic histologic evaluation and scanning electron microscopic (SEM) analysis. RESULTS Group V--Perforations occurred in 18% of the eyes during surgery. Light microscopy revealed exposure of DM in 28% of the eyes with mean thickness of the remaining stroma being 70.4 μm. Group A--Perforations occurred in 42% of the eyes. Light microscopy revealed exposure of DM in 60% of the eyes with mean thickness of the remaining stroma being 23.3 μm. No significant differences in safety, efficacy and thickness of the remaining stroma (including all eyes or excluding those with DM exposure) were observed. SEM of the surgical site revealed a more even surface in those eyes with DM exposure compared to eyes with thicker remaining stroma in both groups. CONCLUSIONs We describe two DALK techniques (viscodissection and big-bubble) for use in horses. No significant differences in safety, efficacy and thickness of the remaining stroma were observed. However, a nonsignificant trend toward the big-bubble technique being more efficacious but less safe was observed.

Femtosecond laser and big-bubble deep anterior lamellar keratoplasty: a new chance.

Purpose. To report the 12-month follow-up after big-bubble deep anterior lamellar keratoplasty (DALK) assisted by femtosecond laser that we have called IntraBubble. Methods. A 60 kHz IntraLase femtosecond laser (Abbott Medical Optics) firstly created a 30° angled intrastromal channel to insert the air injection cannula, 50 μ above the thinnest corneal site measured by Sirius Scheimpflug camera (CSO, Firenze, Italy), then performed a full lamellar cut 100 μ above the thinnest corneal point, and from the same corneal depth, created a mushroom incision. The lamella was removed, and the smooth cannula of Fogla was inserted into the stromal channel and air was injected to achieve a big bubble. The follow up is 12 months, and sutures were removed by the 10th postoperative month in all patients. Best Corrected Visual Acuity (BCVA), spherical equivalent and, by Sirius Scheimpflug camera (CSO, Firenze, Italy) keratometric astigmatism were evaluated. Results. All procedures were completed as DALK except 2 converted to PK because an inadvertent intraoperative macroperforation occurred. Mean postoperative BCVA was 0.8, mean spherical equivalent was -3.5 ± 1.7 D, and mean keratometric astigmatism was 4.8 ± 3.1 D. Conclusion. The femtosecond laser could standardize the big-bubble technique in DALK, reducing the risk of intraoperative complications and allowing good refractive outcomes.

Modified Deep Anterior Lamellar Keratoplasty in the Management of Small and Large Epithelialized Descemetoceles

Descemetocele is a severe complication of corneal ulceration associated with a high risk of perforation. We describe a modified air-assisted deep anterior lamellar keratoplasty (DALK) technique for the surgical management of small and large epithelialized descemetoceles. Two representative cases are presented, one with a small (2 mm) and one with a large (4 mm) descemetocele. In both cases, the air-assisted lamellar dissection allowed a superficial keratectomy and access to the Descemet membrane. Viscoelastic was then directly injected through the stromal hole to separate the Descemet membrane from the posterior stroma, thereby allowing its complete removal. DALK was successfully performed using this modified air-assisted DALK technique. Visual acuity improved from counting fingers and hand motion to 20/40 and was maintained for at least 1 year after surgery. These cases demonstrate that the modified air-assisted DALK technique may be proposed for the management of small and large descemetoceles, allowing both tectonic and visual rehabilitation.

“Double bubble” deep anterior lamellar keratoplasty for management of corneal stromal pathologies

'Big Bubble' deep anterior lamellar keratoplasty (DALK) is becoming an accepted corneal transplantation technique for keratoconus and other anterior stromal corneal pathologies that spare the Descemet's membrane (DM) and endothelium. However, it is not always possible to conclusively recognise formation and identification of the 'Big Bubble'. We describe the surgical technique of DALK called 'Double Bubble' technique that allows the surgeon to definitely and immediately identify the formation of an adequate big bubble. DALK was performed using the 'Double Bubble' technique in twelve eyes of twelve patients with corneal stromal pathologies (keratoconus, 9 eyes; macular corneal dystrophy, 2 eyes; postinfectious keratitis corneal stromal scar, 1 eye) at the Royal Victorian Eye and Ear Hospital, Melbourne. Big bubble was successfully formed in 10 eyes. Maximum-depth deep lamellar keratoplasty was performed in two eyes. There were no instances of intraoperative perforation of the DM. All grafts were clear at last follow-up. Best-corrected visual acuity of≥20/40 was achieved in all the cases at last follow-up (6-12months). 'Double Bubble' DALK helps in identification of the big bubble and has the potential to increase the success of standard 'Big Bubble' DALK in patients with corneal stromal pathologies sparing the DM and endothelium.

Influence of Graft–Host Interface on the Quality of Vision After Deep Anterior Lamellar Keratoplasty in Patients With Keratoconus

To investigate the influence of graft–host interface on the quality of vision after deep anterior lamellar keratoplasty (DALK). Retrospective, nonrandomized, comparative case series. Sixty patients (60 eyes) with advanced keratoconus underwent DALK using the big-bubble technique. Twenty-eight patients had complete stromal excision with Descemet membrane (DM) exposure[DALK with DM baring (DM-DALK)], whereas in 32 cases, a layer of stroma was left adherent to the recipient DM [DALK without DM baring (pre-DM-DALK)]. Twenty-two patients with keratoconus (22 eyes) who underwent penetrating keratoplasty (PK) were chosen for comparison. Main outcome measures were uncorrected visual acuity, best spectacle-corrected visual acuity, low-contrast visual acuity(LCVA), and Pelli-Robson contrast sensitivity. Uncorrected visual acuity was equal in the 3 groups. Median best spectacle–corrected visual acuity was 0.1 logarithm of the minimum angle of resolution (logMAR) in the PK group, compared with 0.06 logMAR in the DM-DALK group (P = 0.66) and 0.12 logMAR in the pre-DM-DALK group (P = 0.016). Pre-DM-DALK patients exhibited worse LCVA than PK (P = 0.029) and DM-DALK patients (P = 0.022), whereas PK and DM-DALK patients showed comparable LCVA (P = 0.974). Pelli-Robson contrast sensitivity was equivalent in PK and DM-DALK groups (P = 0.408) and greater in DM-DALK group than in pre-DM-DALK group (P = 0.038). In selected patients, quality of vision after DALK was comparable to that after PK when stromal excision was extended to the DM and inferior to vision after PK when layers of stroma were left adherent to the DM. Advances in DALK technique are required to allow easier and repeatable baring of the DM.

Standardized big-bubble technique in deep anterior lamellar keratoplasty assisted by the femtosecond laser

We describe a variant of the big-bubble technique in deep anterior lamellar keratoplasty (DALK) assisted by the IntraLase femtosecond laser, which we call IntraBubble. The use of the 60 kHz IntraLase femtosecond laser allows dissection of the pre-Descemet-plane lamella to a predefined corneal depth and creation of a channel in the posterior stroma 50 μm above the endothelium into which a smooth cannula for air injection can be introduced. We lengthened the channel created by the laser using a pointed dissector. Eleven consecutive patients with keratoconus were treated, and all procedures were completed as DALK. The big bubble was achieved in 8 eyes (73%). In 3 cases (27%), intraoperative microperforations occurred and the procedures were completed with hand dissection without complications. This new application of femtosecond laser technology could lead to standardization of the big-bubble technique in DALK.

Traumatic wound dehiscence after deep anterior lamellar keratoplasty

We report the case of a 12-year-old boy with severe keratoconus who had uneventful deep anterior lamellar keratoplasty (DALK) using the big-bubble technique in the left eye for severe loss of best spectacle-corrected visual acuity and contact lens intolerance. Two weeks after surgery, the patient experienced accidental blunt trauma to the operative eye and developed a traumatic 180-degree superior wound dehiscence of the lamellar graft without perforation into the anterior chamber. The DALK technique provided adequate tectonic support to prevent a ruptured globe throughout the traumatic event in contrast to penetrating keratoplasty, which can lead to devastating vision damage after blunt trauma. The traumatic wound dehiscence was repaired without entry into the anterior chamber, and the patient had a successful, quick recovery in visual acuity with no permanent damage to the eye.

Simplified Technique for Deep Anterior Lamellar Keratoplasty

To describe a new technique for performing deep anterior lamellar keratoplasty (DALK) that can be done without special instruments and where deep stromal dissection can be performed under direct visualization. In this prospective, noncomparative case series, DALK was performed by first creating a scleral pocket incision to initiate corneal dissection and continuing further dissection under direct visualization after partial trephination. Fourteen eyes of 13 patients with corneal pathology not involving endothelium were operated on by using the new technique. Accidental entry into the anterior chamber occurred in only 1 eye (7.1%). After a mean follow-up of 10.3 +/- 4 months, the graft was clear in 12 eyes (92.3%), and all 12 eyes had a best-corrected visual acuity of 20/60 or better at this time. Our technique for DALK offers an alternative to the currently used techniques.

Deep Anterior Lamellar Keratoplasty for Post-LASIK Ectasia

To describe 2 cases of post-laser in situ keratomileusis (LASIK) ectasia managed with deep anterior lamellar keratoplasty (DALK). Clinical findings, surgical interventions, and outcomes are reported. The surgical technique of DALK is described. Two patients developed progressive loss of vision after LASIK surgery with enhancement procedure(s). Corneal ectasia was diagnosed on the basis of clinical findings, progressive central corneal thinning on pachymetry, and topographical changes with irregular astigmatism and inferior corneal steepening. Both patients underwent uneventful DALK surgery, in which the anterior 80% of the central corneal stroma was replaced by a donor button and sutured in place. The postoperative recovery was uneventful, except for mild interface haze in 1 case, which resolved within 2 weeks of surgery. However, 1 patient underwent additional surgery, including clear lens extraction with intraocular lens placement, astigmatic keratotomies, and photorefractive keratectomy (PRK) to achieve good unaided visual acuity. At last follow-up, at least 2 years after DALK, both patients were satisfied with their vision. Their uncorrected visual acuity (UCVA) was 20/60+ and 20/40- in their operated eyes, improving to 20/40+ and 20/30- with minimal refractive corrections. The grafts and lamellar interfaces were clear. We believe that DALK should be considered as an alternative to penetrating keratoplasty for the surgical management of post-LASIK ectasia.