Big-Bubble Deep Anterior Lamellar Keratoplasty Assisted by Femtosecond Laser in Children

Update on Pediatric Corneal Diseases and Keratoplasty

Managing pediatric corneal disorders is challenging as the prognosis of pediatric keratoplasty depends on several factors. Advancements in the genetic basis of congenital corneal diseases and investigations in congenital corneal conditions provide a better understanding of pediatric corneal conditions. Surgeons performing keratoplasty in children now have a choice of various techniques. Evolving surgical techniques of anterior lamellar and endothelial keratoplasties has expanded the management interventions in these pediatric corneal morbidity conditions; however, considerable concerns still exist in association with corneal transplantation in infants and children. Outcomes in pediatric keratoplasty depend upon the preoperative indications, the timing of surgical intervention, intraoperative and postoperative factors including the patient/care givers' compliance. Factors such as low scleral rigidity, higher rate of graft failure, need for frequent examinations under anesthesia, and difficulty in optimal visual acuity assessment still remain a considerable challenge in pediatric scenarios. In children, deprivation amblyopia as a result of the corneal opacification can adversely affect visual development, causing dense amblyopia. Outcomes to surgical interventions for management of corneal opacification in children is further compromised by the pre-existing amblyopia apart from the concerns of refractive outcome of the graft. Graft rejection, graft infection, amblyopia, and glaucoma continue to be serious concerns. In recent years both anterior and posterior lamellar keratoplasty techniques are being increasingly performed in pediatric eyes, which offer advantages in the form of lower risk of graft rejection. The timing of surgery, careful case selection, cautious intraoperative approach, and optimal postoperative management can improve the anatomical and functional outcome in difficult cases.

Shaped corneal transplantation surgery

Since its inception in 1905, keratoplasty techniques have continuously evolved. Shaped keratoplasty procedures have allowed corneal surgeons to use complex graft-host junctions and non-circular graft designs to optimise wound strength and healing, facilitate early suture removal and expedite visual rehabilitation. While this was initially limited to penetrating procedures, shaped lamellar keratoplasty techniques have since emerged. Furthermore, the arrival of femtosecond laser has dramatically increased the range of graft designs available to surgeons, due to the technology's ability to precisely cut complex wound edges. This review describes the broad range of shaped keratoplasty grafts currently available and elaborates on their respective advantages and disadvantages in relation to conventional keratoplasty.

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

PURPOSE

To evaluate the outcomes and complications of deep anterior lamellar keratoplasty (DALK) performed for pediatric keratoconus.

METHODS

This retrospective study enrolled 44 consecutive eyes of 39 keratoconus-affected children (≤ 18 years 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.

RESULTS

The mean participant age was 16.8 ± 1.4 years, and the mean follow-up period was 68.5 ± 39.9 months. 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 ± 5.17 D preoperatively to 46.23 ± 2.17 D 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.

CONCLUSION

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.

Single-piece femtosecond-assisted mushroom keratoplasty in children

PURPOSE

To report outcomes of femtosecond-assisted single-piece mushroom keratoplasty for the treatment of full-thickness corneal disease in pediatric patients with healthy endothelium.

METHODS

Femtosecond-assisted mushroom keratoplasty was performed in 8 eyes of 8 patients (age range, 8-17 years) with central full-thickness corneal opacity. The single-piece mushroom-shaped graft consisted of a large anterior portion (9 mm in diameter; 250 μm in thickness) and a small posterior portion (6-6.5 mm). Donor and recipient corneas were prepared using the WaveLight FS200 laser (Alcon Laboratories, Fort Worth, TX). The donor cornea was oversized by 0.2 mm. Outcome measures were best spectacle-corrected visual acuity, spectacle refraction, topographic astigmatism, endothelial cell density, graft rejection, and graft failure at 1, 3, 6, and 12 months.

RESULTS

Mean best spectacle-corrected visual acuity at 1, 3, 6, and 12 months was 0.28, 0.16, 0.13, and 0.10 logMAR; all patients achieved logMAR of at least 0.4 at 1, 3, 6, and 12 months. The mean refractive cylinder was 2.6 D, and mean endothelial cell loss was 13.3% at 12 months postoperatively. Two eyes had immunologic rejection episodes that were reversed with topical steroids. All corneas remained clear at final follow-up.

CONCLUSIONS

Femtosecond-assisted mushroom keratoplasty is a viable surgical option for eyes of older pediatric patients with full-thickness corneal stromal disease and healthy endothelium. Mushroom keratoplasty combines the refractive advantage of a large keratoplasty with the immunologic advantage of a small keratoplasty. Single-piece femtosecond-assisted mushroom keratoplasty may have a mechanical advantage over regular penetrating keratoplasty.

Refractive outcome of keratoconus treated by big-bubble deep anterior lamellar keratoplasty in pediatric patients: two-year follow-up comparison between mechanical trephine and femtosecond laser assisted techniques

Background

To evaluate refractive outcome 24 months after Deep Anterior Lamellar Keratoplasty (DALK) in pediatric patients by comparing results achieved using mechanical trephine and femtosecond laser.

Methods

Twenty eyes of 20 patients affected by keratoconus were evaluated. To perform big-bubble DALK, 10 eyes (Group 1; mean age 11.2 ± 2.2 years) were subjected to the Hessburg-Barron mechanical trephine and the remaining 10 eyes (Group 2; mean age 11.3 ± 3.1 years) to a 150 kHz femtosecond laser that performed mushroom incisions. Preoperative thinnest point in the corneal thickness map and K readings were measured by the Sirius Scheimpflug camera. We also evaluated corrected distance visual acuity (CDVA) as logMAR value using spectacles, spherical equivalent and refractive astigmatism.

Results

Mean preoperative thinnest point and pre- and post-operative K readings did not show significant difference (P > 0.05) between the two groups. CDVA, spherical equivalent and refractive astigmatism were respectively, 0.14 ± 0.08 logMAR and 0.13 ± 0.10 logMAR (P = 0.8), − 4.2 ± 1.1 D and − 2.8 ± 1.2 D (P = 0.03), 4.4 ± 2.0 D and 3.6 ± 1.2 D (P = 0.4) in Groups 1 and 2. All DALK procedures were uneventful.

Conclusion

Our findings suggest that femtosecond laser compared to mechanical trephine could significantly reduce the spherical equivalent amount in pediatric big-bubble DALK.

Femtosecond laser-assisted deep anterior lamellar keratoplasty with big-bubble technique for keratoconus

Purpose:

The purpose of this study was to evaluate the clinical results after deep anterior lamellar keratoplasty (DALK) assisted by the femtosecond laser with big-bubble technique for keratoconus.

Methods:

A case series of 22 eyes in 19 patients with keratoconus was enrolled in the study. The 500-kHz VisuMax femtosecond laser (Carl Zeiss Meditec AG, Jena, Germany) was used to create a vertical side cut on donor and recipient corneas. Intraoperative and postoperative complications, uncorrected visual acuity, best-corrected visual acuity, corneal curvature, and central corneal thickness were evaluated in all patients.

Results:

Big-bubble and naked Descemet's membrane (DM) were successfully achieved in twenty eyes (90.9%). Intraoperative macroperforation of DM occurred in two cases and converted to full-thickness keratoplasty. The mean follow-up time was 18.8 ± 5.3 months. The best-corrected visual acuity was increased from 0.3 to 1.0, mean corneal curvature was 43.0 ± 2.3D, and mean central corneal thickness was 508.9 ± 60.1 μm (range, from 430 to 600 μm) postoperatively.

Conclusion:

Our results indicate that femtosecond laser-assisted DALK with big-bubble technique is an accurate, safe, and effective method to treat the patients with keratoconus.

The challenging management of pediatric corneal transplantation: an overview of surgical and clinical experiences

PURPOSE

Pediatric keratoplasty is an immense challenge because of the technical complexity of the procedure and the high risk of rejection in young graft recipients. Our aim is to describe the major indications and appropriate timing of corneal transplantation intervention, including a report of our experience and surgical tips, in conjunction with the current literature.

METHODS

Review of the literature on indications for keratoplasty in pediatric patients classified as: congenital, traumatic and acquired non-traumatic opacities. We additionally explored the challenges corneal surgeons face in performing this type of surgery and review the most pressing transplant-related problems and their management.

RESULTS

Outcomes after pediatric keratoplasty, in terms of visual development, restoration and clarity of the graft, are influenced by peri-operative local and systemic conditions and factors, and by intraoperative management of the transplantation procedure itself.

CONCLUSION

Pediatric corneal transplantation is a critical tool for visual restoration and development in young patients with corneal opacities, particularly during the critical period of visual development. Successful management of the significant challenges associated with pediatric keratoplasty requires customized clinical and surgical management of each patient with particular attention paid to proper post-operative rehabilitation.

Four years of corneal keratoplasty in Italian paediatric patients: indications and clinical outcomes

PURPOSE

The purpose was to evaluate indications and clinical outcomes in paediatric corneal keratoplasty.

METHODS

Fifty-four eyes of 43 patients who underwent corneal keratoplasty from the 1^st of January 2010 through the 31^st of December 2013 at the Bambino Gesù Children's Hospital in Rome, Italy, were retrospectively evaluated. To assess the effect of age on graft failure rate, the recipient age was considered as a dichotomous variable (≤5 or >5 years) and a 2X2 table was developed, using the chi-square test for testing the statistical significance. Furthermore, two separate subgroup analyses were conducted on patients of ≤5 years and those of >5 years, to evaluate the effect of penetrating keratoplasty (PK) or deep anterior lamellar keratoplasty (DALK) on the graft failure rate. The level of statistical significance was set at p < 0.05 RESULTS: Mean recipient age was 8.9 ± 5.7 [SD] years. Mean follow-up time was 22.8 months. Main preoperative diagnoses were keratoconus (37 %) and congenital glaucoma (20 %). Patients ≤5 years showed a higher percentage of graft failure (p = 0.0008). PK and DALK did not show statistically significant differences regarding the graft failure in both subgroups (p = 0.15 for ≤5 years group and p = 0.27 for >5 years group, respectively). However, across groups DALK provided a lower rate of graft failure.

CONCLUSIONS

Our findings suggest that children older than 5 years show a significantly better graft outcome and that DALK seems to offer greatest benefits in terms of failure risk in paediatric patients.

Treatment options for advanced keratoconus: A review

Traditionally, the mainstay of treatment for advanced keratoconus (KC) has been either penetrating or deep anterior lamellar keratoplasty (PK or DALK, respectively). The success of both operations, however, has been somewhat tempered by potential difficulties and complications, both intraoperatively and postoperatively. These include suture and wound-healing problems, progression of disease in the recipient rim, allograft reaction, and persistent irregular astigmatism. Taken together, these have been the inspiration for an ongoing search for less troublesome therapeutic alternatives. These include ultraviolet crosslinking and intracorneal ring segments, both of which were originally constrained in their indication exclusively to eyes with mild to moderate disease. More recently, Bowman layer transplantation has been introduced for reversing corneal ectasia in eyes with advanced KC, re-enabling comfortable contact lens wear and permitting PK and DALK to be postponed or avoided entirely. We offer a summary of the current and emerging treatment options for advanced KC, aiming to provide the corneal specialist useful information in selecting the optimal therapy for individual patients.

Femtosecond laser-assisted deep anterior lamellar keratoplasty for keratoconus and keratectasia

AIM

To describe the initial outcomes and safety of femtosecond laser-assisted deep anterior lamellar keratoplasty (DALK) for keratoconus and post-LASIK keratectasia.

METHODS

In this non-comparative case series, 10 eyes of 9 patients underwent DALK procedures with a femtosecond laser (Carl Zeiss Meditec AG, Jena, Germany). Of the 9 patients, 7 had keratoconus and 2 had post-LASIK keratectasia. A 500 kHz VisuMax femtosecond laser was used to perform corneal cuts on both donor and recipient corneas. The outcome measures were the uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), corneal thickness, astigmatism, endothelial density count (EDC), and corneal power.

RESULTS

All eyes were successfully treated. Early postoperative evaluation showed a clear graft in all cases. Intraoperative complications included one case of a small Descemet's membrane perforation. Postoperatively, there was one case of stromal rejection, one of loosened sutures, and one of wound dehiscence. A normal corneal pattern topography and transparency were restored, UCVA and BCVA improved significantly, and astigmatism improved slightly. There was no statistically significant decrease in EDC.

CONCLUSION

Our early results indicate that femtosecond laser-assisted deep anterior lamellar keratoplasty could improve UCVA and BCVA in patients with anterior corneal pathology. This approach shows promise as a safe and effective surgical choice in the treatment of keratoconus and post-LASIK keratectasia.

Deep anterior lamellar keratoplasty in case of Hurler-Scheie syndrome

A 12-year-old boy with Hurler-Scheie syndrome (H/S syndrome) reported with reduced vision in both the eyes for past few years. Deep anterior lamellar keratoplasty (DALK) was performed for visual rehabilitation in his left eye. During surgery, the predescemet's plane was reached by meticulously dissecting the lamellar fibres using a manual technique. Histopathology of the dissected cornea showed the presence of numerous alcian blue positive deposits corroborating with the diagnosis of mucopolysaccharidosis (MPS). Postoperative course was uneventful. One year following surgery, the graft was clear and had a visual acuity of 20/50 with +1.00 170° - 0.75 refractive correction. Endothelial cell count, as measured by non-contact specular microscopy, was 2473.4 cells/mm(2). This case report highlights the application of DALK in a case of MPS-related corneal stromal opacification.

One Year of Cornea Research in Review-2012

PURPOSE

The purpose of this study was to provide an update of significant cornea literature published in the past 1 year.

DESIGN

This was a literature review.

METHODS

The authors conducted a 1-year English-language literature search on PubMed, from January 1, 2012, to December 31, 2012, using the following terms: corneal transplantation, anterior lamellar keratoplasty, penetrating keratoplasty, endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty, Descemet membrane endothelial keratoplasty, Descemet membrane endothelial transfer, ocular surface epithelial transplantation, limbal epithelial transplantation, cultivated oral mucosal epithelial transplantation, keratoprosthesis, infectious keratitis, cross-linking, keratoconus, corneal neovascularization, corneal imaging, optical coherence tomography, Pentacam Scheimpflug imaging, and in vivo confocal microscopy.

RESULTS

This review includes original articles and review articles that contain significant updates and novel aspects in the field of cornea from the following journals: American Journal of Ophthalmology, British Journal of Ophthalmology, Ophthalmology, Investigative Ophthalmology and Visual Science, and Cornea. Letters to the editor, unpublished work, manuscripts not in English, and abstracts were not included.

CONCLUSIONS

This review highlights significant literature that is applicable to the practicing ophthalmologist.

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.