OBJECTIVE: The aim of the study was to analyze the techniques and outcomes of deep anterior lamellar keratoplasty (DALK) done in eyes with healed hydrops.
METHODS: Thirty-one eyes with paracentral scars following acute hydrops underwent DALK and were included in the study. Manual layer-by-layer dissection with stromal air injection was done in all cases, keeping dissection of the site of preexisting perforation to the end.
RESULTS: Out of the 31 eyes, in 28 eyes, DALK could be completed, and in 3 eyes, procedure had to be converted to penetrating keratoplasty. Visual outcomes in all cases were good, with 26 out of 28 eyes (92.8%) achieving a best-corrected visual acuity (BCVA) of 6/12 or better. Preoperative mean BCVA of LogMAR 1.19 ± 0.27 improved to a postoperative mean BCVA of LogMAR 0.23 ± 0.08 (P < 0.00001). Postoperative mean refractive astigmatism at the last follow-up was -2.69 ± 0.82 D with postoperative a spherical equivalent of -2.31 ± 0.7 D. Complications included double anterior chamber in one eye and secondary angle closure in two eyes. Stromal rejection in one eye was managed with steroids and one eye with suture infiltrate needed selective suture removal.
CONCLUSIONS: Layer-by-layer dissection with limited air injection into the stroma has shown good visual outcomes in patients undergoing DALK following healed hydrops, and DALK can very well be the primary treatment option even in such cases with a paracentral posthydrops scar.

The aim of our study is to investigate the feasibility and outcomes of using a femtosecond laser (FSL) platform (Ziemer LDV Z8) for deep anterior lamellar keratoplasty (DALK), enabling the creation of mushroom-shaped graft-host junctions, lamellar cuts, and intrastromal tunnels, to facilitate the big bubble, in one step. We included wet lab experiments on nine porcine eyes to assess the laser accuracy and cuts depth using an anterior segment (AS) OCT. This was followed by an interventional prospective case series on 10 eyes with variant corneal pathologies. The Z8 system, with in-built intraoperative optical coherence tomography (iOCT), guided corneal scans and directed the cuts. ASOCT showed visible mushroom configurations, lamellar cuts, and tunnels. Deviations from the target were 1.6%, 2.6%, and 3.5%. Anterior lamellar removal was easy in all clinical cases, including corneal scarring. The intrastromal tunnel was found at the preset location and the mushroom configuration was acquired. A big bubble was achieved in all cases. Type 1, 2, and 3 bubbles were formed in eight, one, and one case, respectively. We describe a new approach to DALK in which the in-built iOCT-guided FSL enables safe, precise, controlled, and reproducible desired cuts in one step. The preliminary clinical outcomes were favorable.

Partial-thickness corneal transplants using a deep anterior lamellar keratoplasty (DALK) approach has demonstrated better patient outcomes than a full-thickness cornea transplant. However, despite better clinical outcomes from the DALK procedure, adoption of the technique has been limited because the accurate insertion of the needle into the deep stroma remains technically challenging. In this work, we present a novel hands-free eye mountable robot for automatic needle placement in the cornea, AutoDALK, that has the potential to simplify this critical step in the DALK procedure. The system integrates dual light-weight linear piezo motors, an OCT A-scan distance sensor, and a vacuum trephine-inspired design to enable the safe, consistent, and controllable insertion of a needle into the cornea for the pneumodissection of the anterior cornea from the deep posterior cornea and Descemet\'s membrane. AutoDALK was designed with feedback from expert corneal surgeons and performance was evaluated by finite element analysis simulation, benchtop testing, and ex vivo experiments to demonstrate the feasibility of the system for clinical applications. The mean open-loop positional deviation was 9.39 µm, while the system repeatability and accuracy were 39.48 µm and 43.18 µm, respectively. The maximum combined thrust of the system was found to be 1.72 N, which exceeds the clinical penetration force of the cornea. In a head-to-head ex vivo comparison against an expert surgeon using a freehand approach, AutoDALK achieved more consistent needle depth, which resulted in fewer perforations of Descemet\'s membrane and significantly deeper pneumodissection of the stromal tissue. The results of this study indicate that robotic needle insertion has the potential to simplify the most challenging task of the DALK procedure, enable more consistent surgical outcomes for patients, and standardize partial-thickness corneal transplants as the gold standard of care if demonstrated to be more safe and more effective than penetrating keratoplasty.

Acanthamoeba keratitis (AK) is a rare, sight-threating corneal infection. The disease is challenging to diagnose and treat, and the amoeba can rapidly encyst, persisting in the tissue and causing recurrences. Medical therapy is conventionally considered the first line treatment, but advanced cases could require more invasive treatments like a \"chaud\" corneal transplant. We review the incidence of severe complications in patients affected by AK. Of 439 reports screened, 158 met our inclusion criteria. Incidence of severe complications was low, with 2.21 % patients developing perforation, 1 % requiring evisceration/enucleation and less than 1 % developing endophthalmitis. Corneal transplantation was required in 16.68 % of the cases. According to our results, and considering the reported incidences of these complications in other infectious keratitis, AK patients have an overall low risk of developing perforation, endophthalmitis, and enucleation/evisceration. Nevertheless, data available in the literature remain poor, and further randomized control trials are needed to confirm our findings.

Selective keratoplasty involves replacing the affected layers of the cornea with similar donor tissue. In case of pathological changes in the middle and posterior stroma, deep anterior lamellar keratoplasty (DALK) is performed. Chronic corneal edema caused by endothelial dysfunction is an indication for endothelial keratoplasty - Descemet membrane endothelial keratoplasty (DMEK) or Descemet Stripping Endothelial Keratoplasty (DSAEK). Compared to penetrating keratoplasty (PK), these operations are characterized by a low risk of damage to intraocular structures and a relatively short rehabilitation period. Complications of selective keratoplasty include the formation of a false chamber between the lamellar graft and the recipient\'s cornea, ocular hypertension during anterior chamber air tamponade. Persistent epithelial defect can be a sign of primary graft failure in DALK, DSAEK and DMEK. Selective keratoplasty is characterized by a lower incidence of immune rejection than PK. In some cases, DALK can be complicated by corneal changes related to suture fixation of the graft. Long-term postoperative use of topical glucocorticoids can cause ocular hypertension and cataracts.
Селективная кератопластика включает в себя замещение пораженных слоев роговицы аналогичной тканью донора. При патологических изменениях средних и задних отделов стромы выполняют глубокую переднюю послойную кератопластику (ГППК). Хронический отек роговицы, вызванный дисфункцией эндотелиального слоя, является показанием к проведению эндотелиальной кератопластики — трансплантации десцеметовой мембраны (ТДМ) или задней автоматизированной кератопластики (ЗАПК). По сравнению со сквозной кератопластикой (СКП) такие операции характеризуются низким риском повреждения интраокулярных структур и относительно коротким реабилитационным периодом. К осложнениям селективной кератопластики относят формирование ложной камеры между послойным трансплантатом и роговицей реципиента и офтальмогипертензию на этапе пневмотампонады передней камеры. Персистирующий эпителиальный дефект может быть признаком первичной несостоятельности трансплантата при ГППК, ЗАПК и ТДМ. Селективная кератопластика характеризуется более низкой частотой развития реакции иммунного отторжения трансплантата, чем СКП. При ГППК возможны изменения роговицы, обусловленные шовной фиксацией трансплантата. Длительное применение глюкокортикостероидов (в инстилляционной форме) после операции может быть причиной офтальмогипертензии и катаракты.

Deep anterior lamellar keratoplasty (DALK) involves the selective replacement of diseased corneal stroma while preserving healthy unaffected endothelium. While DALK has failed to gain widespread popularity, improved visual and refractive outcomes of large-diameter grafts, which patients directly perceive following suture removal, may represent a compelling reason to shift toward DALK. Since the unaffected host endothelium is retained, DALK offers the opportunity to use large-diameter grafts, which reliably achieves maximum visual potential without an increased risk of immune-mediated stromal rejection. In this narrative review, we evaluate the current evidence on large-diameter DALK including surgical technique and clinical outcomes.

Pediatric corneal transplant is a highly demanding and technically challenging procedure for the cornea surgeon in today\'s era. These cases pose unique challenges in clinical and surgical management. The indications of pediatric corneal transplant can be therapeutic, tectonic, optical, and cosmetic. Pediatric patients undergoing corneal transplants are at a high risk of graft infection, failure, rejection, dehiscence, and amblyopia due to young age, robust immune system, increased incidence of trauma, and compliance issues. The other factors contributing to graft failure can be allograft rejection, secondary glaucoma, corneal vascularization, multiple surgeries, vitreous prolapse, and lack of treatment compliance. A successful corneal transplant in children depends on meticulous preoperative evaluation, uneventful surgery, the expertise of a corneal surgeon, and regular and timely postoperative follow-up. Therapeutic and optical penetrating keratoplasty are the most commonly performed transplants in children. However, with the advancements in surgical technique and management protocol, the current focus has shifted toward lamellar keratoplasty. Lamellar keratoplasty offers early visual recovery and potentially fewer complications. Visual rehabilitation through corneal transplant in otherwise blind eyes can be a boon for the children. Recently, keratoprostheses have been promising in children with multiple graft failures. The current review gives insights into epidemiology, etiology, indications, clinical characteristics, investigations, management options, recent advances, and the future of pediatric corneal transplants. As surgical techniques continue to grow and comprehension of pediatric corneal transplants is improving, we can safeguard these eyes with the best possible anatomical and functional outcomes.

Pseudomonas keratitis is an aggressive form of bacterial keratitis that can have devastating consequences, such as corneal perforation, if not promptly identified and appropriately managed. The aim of this case report is to highlight key clinical features of Pseudomonas keratitis and evaluate the initial and long-term management options for this condition. We report a case of a 32-year-old female who presented with a large corneal abscess and hypopyon following contact lens wear. Corneal cultures confirmed Pseudomonas as the causative organism and she was treated with topical levofloxacin and gentamycin. Following sterilisation of the corneal ulcer, the patient was left with deep stromal scarring, peripheral corneal thinning as well as four-quadrant deep corneal vascularisation. She was listed for deep anterior lamellar keratoplasty surgery to clear her visual axis. We highlight some of the challenges that were faced both intra-operatively and post-operatively and how they were managed.

This report describes deep anterior lamellar keratoplasty over penetrating keratoplasty (DALK-over-PKP) as an alternative technique to mitigate complications related to positive vitreous pressure (PVP) during PKP. We accomplished this by repairing the punctured cornea and performing a modified DALK where a full-thickness donor graft is placed over the host Descemet membrane, which is then removed after partial suturing of the graft. This mitigates the driving force behind the PVP by maintaining a closed-anterior chamber.

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