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AIM: To evaluate the clinical efficacy of small-diameter acellular porcine corneal stroma (SAPS) for the treatment of peripheral corneal ulceration (PCU). METHODS: This retrospective clinical study included 18 patients (18 eyes) with PCU between April 2018 and December 2020. All patients had PCU and underwent lamellar keratoplasty with SAPS. Observation indicators included preoperative and postoperative best-corrected visual acuity (BCVA) and transparency of SAPS. The infection control rate in the surgical eye-lesion area was also calculated. RESULTS: Eighteen patients underwent lamellar keratoplasty with SAPS to treat PCU. None of the patients experienced rejection after 6mo (18/18) and 12mo (16/16) of follow-up. The BCVA (0.47±0.30) at the 6mo follow-up after operation was significantly improved compared with the baseline (0.99±0.80), and the difference was statistically significant (Z=-3.415, P

This review highlights the evolution in the scope of eye banking activities in India. The roles and responsibilities of the eye banks have expanded to match the requirements and necessities that arose because of advancements in keratoplasty techniques and the need for corneal surgeons. Adoption of different types of corneal preservation solutions and methods of donor cornea preservation was a consequence of the changing and unprecedented times. The growth of eye banking in India has been a commendable journey and has placed the country in an "almost sufficient" category in eye banking and corneal transplantation. There exists a potential to reach the status of cornea surplus country in the future. The rules and laws governing eye banking operations need dynamic amendments based on the trends in keratoplasty, surgical practice patterns, and status of self-sufficiency. Newer technological advances and quality measures must be adopted in donor cornea evaluation and tissue preparation. Research should be integrated as an important component of eye banking, especially in developing novel methods of donor preservation, and evaluating and validating the existing and changing practices of eye banking. [ABSTRACT FROM AUTHOR]

Purpose: To report the types of keratoplasty and analyze trends over a period of two decades in central and northern India. Methods: This was a retrospective review of eye bank registries of six tertiary eye care centers located in central and north India from 2005 to 2021. The indications and various keratoplasty procedures were compared between 2005–2012 and 2013–2021 to analyze the trend. Results: A total of 13,223 corneal grafts were performed, of which therapeutic penetrating keratoplasty (TPK) (5719, 43.3%) was the most common procedure, followed by optical penetrating keratoplasty (OPK) (5528, 41.8%), Descemet stripping endothelial keratoplasty (DSEK) (1279, 9.7%), deep anterior lamellar keratoplasty (DALK) (376, 2.8%), Descemet membrane endothelial keratoplasty (DMEK) (215, 1.6%), patch grafts (75, 0.6%), and keratoprostheses (31, 0.2%). Overall, OPK procedures decreased (−14.1%, P < 0.001), but TPK (+3.1%, P < 0.019), DSEK (+7.1%, P < 0.001), and DMEK (+1.9%, P < 0.001) procedures increased. Although there was an increasing trend in the use of DALK (+0.8%, P < 0.083) and keratoprostheses (+0.3%, P = 0.074) procedures, the trends were not statistically significant. Conclusion: In keeping with worldwide trends, an increasing trend in lamellar keratoplasties was observed in central and northern India during the past decade. The trend was significant for DSEK. However, as corneal ulcers and scars were the major indications for keratoplasty, TPK and OPK remained the most common procedures. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare four depths of manual dissection for the preparation of Descemet stripping endothelial keratoplasty lamellae. Methods: Eye bank corneas were randomized into four groups according to dissection depths: Pachy-100 (incision depth = central corneal thickness-safety margin of 100 µm), Pachy-50 (safety margin of 50 µm), Pachy-0 (no safety margin), and Pachy+50 (incision depth = central corneal thickness + 50 µm). All endothelial lamellae were prepared using a standardized method of manual dissection (Pachy-DSEK). The central, paracentral (3.0-mm zone), and peripheral (6.0-mm zone) lamella thicknesses and incision depths were measured by optical coherence tomography. The 3.0-mm and 6.0-mm zone central-to-peripheral thickness ratios were calculated. Results: Endothelial perforation occurred only in the Pachy+50 group (n=3, 30%). Central lamella's thickness in Pachy-100, Pachy-50, Pachy-0, and Pachy+50 groups measured 185 ± 42 µm, 122 ± 29 µm, 114 ± 29 µm, and 58 ± 31 µm, respectively (p<0.001). The overall 3.0- and 6.0-mm C/P ratios were 0.97 ± 0.06 and 0.92 ± 0.14, respectively. Preoperative donor characteristics were not correlated with most thickness outcomes. The planned incision depth correlated significantly with most lamella's thickness parameters (p<0.001). The overall thickness of the lamella negatively correlated with the planned incision depth (p<0.001, r=-0.580). The best outcome was found in the Pachy-0 group, as 75% of the lamellae measured <130 µm and there was no endothelial perforation. Conclusions: By using a standardized method of dissection, most manually prepared lamellae presented a planar shape. Setting the incision depth to the central corneal thickness did not result in endothelial perforation and a high percentage of ultrathin lamellae was achieved. [ABSTRACT FROM AUTHOR]

Abstract Purpose We describe the management of a case of severe corneal melting after corneal cross-linking (CXL) treated with a staged approach using a conjunctival flap followed by deep anterior lamellar keratoplasty (DALK). Methods A 12-year-old male developed severe corneal melting with pending perforation after an accelerated epithelium-off CXL protocol. We initially treated the patient with a conjunctival flap to prevent perforation. Three months later, we performed DALK to restore vision. Results Conjunctival flap surgery allowed us to avoid corneal perforation and penetrating keratoplasty (PK) à chaud. Once the inflammation had resolved, we recessed the conjunctiva and performed DALK for optical purposes. Twelve months later, the graft was clear and the corrected visual acuity was 20/25 (Snellen). No complications occurred after surgery. Conclusions Although CXL is considered a safe procedure, in rare cases it can lead to serious complications, such as corneal haze, infectious and non-infectious keratitis, stromal melting and perforation. Corneal melting and perforation are usually managed by emergency PK. Herein we suggest a staged approach involving an emergency conjunctival flap followed by DALK at a later time that allowed us to avoid PK à chaud.

Silvia Schrittenlocher,1 Jithmi Weliwitage,2 Mario Matthaei,1 Björn Bachmann,1 Claus Cursiefen1,3 1Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, NRW, Germany; 2University of Cologne, Institute for Medical Statistics and Computational Biology (IMSB), Cologne, NRW, Germany; 3University of Cologne, Center for Molecular Medicine Cologne (CMMC), Cologne, NRW, GermanyCorrespondence: Silvia Schrittenlocher, Kerpener Str. 62, Cologne, 50937, Germany, Tel +49 221– 4313, Fax +49 221– 3186, Email Silvia.Schrittenlocher@uk-koeln.dePurpose: To determine which donor characteristics, like previous diseases and surgeries, influence the severity of the DM/endothelial lamella preparation prior to DMEK-surgery.Patients and Methods: Retrospective cross-sectional single-center study is presented. Eight hundred and forty-six eyes with DMEK-surgery between 01/2018 and 01/2021 performed at the University Hospital Cologne, Germany, were included. Information regarding the donors’ previous diseases and surgeries were provided by a large database of a cornea bank (Multi Tissue Bank Mecklenburg-Vorpommern) and merged with the Cologne DMEK database, which contains information regarding preparation characteristics of the surgeon-prepared graft directly preoperatively. Three preparation groups (easy, difficult and very difficult) were correlated to the donors’ previous diseases and surgeries. The following characteristics were used for the assignment in one of the three groups: stripping difficulty, rolling and staining behavior, central and peripheral adherences, tissue fragility and DM-splitting.Results: Significant risk factors for DM-splitting were diabetes mellitus (DMel) type II, heart failure, chronic kidney disease and previous cataract surgery (p=0.022, p=0.012; p=0.047 and p< 0.001 respectively). Previous DMel (especially type 2) was significantly associated with the occurrence of central adherences (p=0.009). Several cardiovascular diseases (p-values between < 0.001 and p=0.038), DMel type II, chronic kidney disease and previous cataract-surgery were associated with peripheral adherences (p=0.004; p=0.020 and p< 0.001 respectively). Furthermore, pseudophakic donor eyes presented a higher degree of fragility of the graft (p< 0.001). Age was a significant risk factor for difficult preparation (p< 0.001). The staining of the graft was poorer in donors with chronic kidney disease (p=0.037).Conclusion: Donor diabetes mellitus type 2, heart failure, previous cataract surgery, chronic kidney disease and age are associated with a difficult DMEK graft preparation. For every one-year increment in donor age, the odds of having very difficult preparation were increased by 3%. Also, chronic kidney disease predisposes to a poor tissue staining with trypan blue during preparation.Keywords: DMEK, lamellar keratoplasty, donor, graft preparation, risk factors, cornea bank

Purpose: We describe the management of a case of severe corneal melting after corneal cross-linking (CXL) treated with a staged approach using a conjunctival flap followed by deep anterior lamellar keratoplasty (DALK). Methods: A 12-year-old male developed severe corneal melting with pending perforation after an accelerated epithelium-off CXL protocol. We initially treated the patient with a conjunctival flap to prevent perforation. Three months later, we performed DALK to restore vision. Results: Conjunctival flap surgery allowed us to avoid corneal perforation and penetrating keratoplasty (PK) à chaud. Once the inflammation had resolved, we recessed the conjunctiva and performed DALK for optical purposes. Twelve months later, the graft was clear and the corrected visual acuity was 20/25 (Snellen). No complications occurred after surgery. Conclusions: Although CXL is considered a safe procedure, in rare cases it can lead to serious complications, such as corneal haze, infectious and non-infectious keratitis, stromal melting and perforation. Corneal melting and perforation are usually managed by emergency PK. Herein we suggest a staged approach involving an emergency conjunctival flap followed by DALK at a later time that allowed us to avoid PK à chaud. [ABSTRACT FROM AUTHOR]

This article discusses a novel technique for performing deep anterior lamellar keratoplasty (DALK) using a femtosecond laser. DALK is a surgical procedure used to treat anterior corneal diseases, and the "big-bubble" technique is commonly used. However, this technique can be difficult and unpredictable. The authors present a case study of a 72-year-old woman with Schnyder dystrophy who underwent femtosecond laser-assisted DALK. The laser cut allowed for the direct removal of the lenticule without manual dissection and without affecting the endothelium. The patient experienced improved visual acuity after the procedure, and no complications were noted. The authors suggest that this technique shows promise for standardized use in the future. [Extracted from the article]

Purpose: To report the types of keratoplasty and analyze trends over a period of two decades in central and northern India. Methods: This was a retrospective review of eye bank registries of six tertiary eye care centers located in central and north India from 2005 to 2021. The indications and various keratoplasty procedures were compared between 2005–2012 and 2013–2021 to analyze the trend. Results: A total of 13,223 corneal grafts were performed, of which therapeutic penetrating keratoplasty (TPK) (5719, 43.3%) was the most common procedure, followed by optical penetrating keratoplasty (OPK) (5528, 41.8%), Descemet stripping endothelial keratoplasty (DSEK) (1279, 9.7%), deep anterior lamellar keratoplasty (DALK) (376, 2.8%), Descemet membrane endothelial keratoplasty (DMEK) (215, 1.6%), patch grafts (75, 0.6%), and keratoprostheses (31, 0.2%). Overall, OPK procedures decreased (−14.1%, P < 0.001), but TPK (+3.1%, P < 0.019), DSEK (+7.1%, P < 0.001), and DMEK (+1.9%, P < 0.001) procedures increased. Although there was an increasing trend in the use of DALK (+0.8%, P < 0.083) and keratoprostheses (+0.3%, P = 0.074) procedures, the trends were not statistically significant. Conclusion: In keeping with worldwide trends, an increasing trend in lamellar keratoplasties was observed in central and northern India during the past decade. The trend was significant for DSEK. However, as corneal ulcers and scars were the major indications for keratoplasty, TPK and OPK remained the most common procedures.

This review highlights the evolution in the scope of eye banking activities in India. The roles and responsibilities of the eye banks have expanded to match the requirements and necessities that arose because of advancements in keratoplasty techniques and the need for corneal surgeons. Adoption of different types of corneal preservation solutions and methods of donor cornea preservation was a consequence of the changing and unprecedented times. The growth of eye banking in India has been a commendable journey and has placed the country in an “almost sufficient” category in eye banking and corneal transplantation. There exists a potential to reach the status of cornea surplus country in the future. The rules and laws governing eye banking operations need dynamic amendments based on the trends in keratoplasty, surgical practice patterns, and status of self-sufficiency. Newer technological advances and quality measures must be adopted in donor cornea evaluation and tissue preparation. Research should be integrated as an important component of eye banking, especially in developing novel methods of donor preservation, and evaluating and validating the existing and changing practices of eye banking.

Late complications of radial keratotomy (RK), are as a rule caused by a change in the biomechanical properties of the cornea.Purpose: to study the long-term stabilizing effect of the Bowman’s layer (BL) transplantation after RK.Material and methods. In a limited, prospective, monocentric pilot study we operated 2 male patients (2 eyes) aged 60 and 55. The radial incisions had been performed 34 and 38 years ago. The indications for surgery were progressive biomechanical instability of the cornea and functional refractive visual fluctuations. Within 12 months after the operation, complications, corrected visual acuity, keratometric parameters, biomicroscopic transparency of the cornea, and patient satisfaction were assessed.Results. No complications were noted during the follow-up period, the cornea and graft retained transparency. The average thickness of the BS graft was 20±2.1 µm. The average visual acuity corrected by contact lenses increased from 0.4±0.3 to 0.65±0.1, the average indicator of keratometric astigmatism changed from 1.9±1.6 to 3.0 D, these indicators remained after 6, 9 and 12 months, which indicates that biomechanical stability of the cornea was achieved and that the refractive-visual fluctuations are absent.Conclusion. In late term RK complications, BS transplantation partially restores the normal anatomy of the anterior surface of the cornea and ensures its biomechanical stability during a 12-month follow-up period. For the conclusions to be maximally objective, more clinical cases should be studied within a longer observation period.

Background : Descemet membrane endothelial keratoplasty (DMEK) is increasingly favored in the treatment of endothelial dysfunction due to its benefits, which include swift visual rehabilitation and recovery, a relatively low rejection rate, and superior refractive stability. In this study, we examined alterations in corneal clarity among patients who underwent DMEK and correlated these densitometry findings with other optical parameters of corneal topography. Methods : The study incorporated 35 eyes from 35 patients who had previously undergone DMEK surgery for pseudophakic bullous keratopathy at Ankara Bilkent City Hospital. The results from these patients were compared with those from a healthy control group. The preoperative and postoperative optical parameters of the patients were assessed using Pentacam Scheimpflug topography (Oculus). Results : We observed significant decreases in corneal densitometry in the 0–2 mm and 2–6 mm zones of the anterior, posterior, central, and total layers at the sixth month postoperatively compared to the preoperative period (P

Abstract Objective Comparing results of two different DALK surgery techniques (big bubble vs. Melles) in patients with advanced keratoconus. Design a retrospective comparative clinical study. Participants This study conducted on 72 eyes of 72 participants. Introduction This study designed to compare the results of two different DALK surgery techniques (big bubble vs. Melles) in patients with advanced keratoconus. Method Thirty-seven eyes were treated using the big bubble DALK method, while 35 eyes were treated using the Melles approach. Uncorrected visual acuity (UCVA), best corrected spectacle visual acuity (BCSVA), manifest refraction, keratometric characteristics, contrast sensitivity, corneal aberrations, corneal biomechanical characteristics, and endothelial cell profile are the outcome measurements. Results Mean UCVA in big bubble group was 0.61 ± 25 LogMAR and in Melles group was 0.89 ± 0.41 LogMAR (p-value 0.043). Mean BCSVA in big bubble group (0.18 ± 0.12 Log MAR) was significantly better than Melles group (0.35 ± 0.16 Log MAR). Mean of sphere and cylinder refraction showed no significant difference between two groups. Comparing the endothelial cell profile, corneal aberrations, corneal biomechanical properties and keratometry had no significantdifferences. Contrast sensitivity reported as modulation transfer function (MTF) showed higher values in big bubble group and differences with Melles group weresignificant. Results of point spread function (PSF) in big bubble group had superiority to Melles group with considerable statistical P value of 0.023. Conclusion When opposed to the Melles approach, the big bubble technique generates a smooth interface with less stromal residue, which results in higher visual quality and contrast sensitivity.

Limbal dermoid is a congenital benign tumor of the limbus which is often managed by surgery if necessary. In dermoid lesions involving the deep stroma, tumor excision and reconstruction of the anterior segment with amniotic membrane transplantation or keratoplasty may be required. Herein, we present a case of deep limbal dermoid treated with surgical resection and lamellar keratoplasty using microkeratome-assisted anterior lamellar graft.

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The ability of the femtosecond laser (FSL) to create tissue incisions at desired depth and location with minimal collateral damage to surrounding tissue may offer potential advantages for corneal transplantation surgery. FSL may enable the precise and accurate preparation of both donor and recipient tissue, which can potentially result in enhanced wound integrity, facilitation of wound healing, and improved visual outcomes. Many studies have suggested that FSL may be a viable option in various corneal transplantation procedures, such as, penetrating keratoplasty, anterior lamellar keratoplasty, endothelial keratoplasty, and novel techniques, including Bowman layer transplantation and stromal lenticule addition keratoplasty. In this review, the author presents a brief overview on the application of FSL in various corneal transplantation procedures and discusses the results of studies regarding the safety and efficacy of FSL-assisted corneal transplantation procedures. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of therapeutic keratoplasty (TKP) in patients with severe Acanthamoeba keratitis (AK) and to analyse the clinical features and risk factors for recurrence. Methods: Clinical data of patients with severe AK treated with lamellar keratoplasty (LK) or penetrating keratoplasty (PK) due to ineffective drug therapy were analysed in this retrospective study. The effects of keratoplasty, clinical features, and risk factors for recurrence were analysed. Results: The cohort comprised of 58 patients (59 eyes). Of these, 36 eyes were treated with PK and 23 were treated with LK. The probabilities of successful globe salvage were 91.7% and 91.3%, respectively. The final visual acuity (VA) was ≥ 20/60 in 14 eyes (38.9%) that underwent PK and 15 eyes (65.2%) that underwent LK. Postoperative recurrence of Acanthamoeba infection was detected in 10 eyes; 6 eyes (16.7%) showed recurrence after PK, and 4 eyes (17.4%) showed recurrence after LK. Recurrence occurred between 3 and 80 days (median, 14.5 days) after the operation. The risk factors for recurrence after LK were topical corticosteroid use before diagnosis (p = 0.040) and hypopyon (p = 0.009), while those after PK were topical corticosteroid use before diagnosis (p = 0.045). Clinical manifestations of postoperative recurrence include greyish-white infiltration of the recipient bed, anterior chamber inflammation, graft oedema, and keratic precipitate. Conclusion: TKP is a treatment option for severe AK that responds poorly to antiamoebic therapy (AAT), although Acanthamoeba infection may relapse, and the visual prognosis is guarded. Topical corticosteroid use before AAT and hypopyon is the two risk factors for recurrence. [ABSTRACT FROM AUTHOR]

Among the various indications for keratoplasty, failed graft is one of the commonest indications in many published series. It is well known that the major cause of graft failure is endothelial rejection. In the last two decades, there has been a major paradigm shift in the surgical management of corneal diseases, and component keratoplasty has emerged from the concept of replacing the layer that is actually diseased, rather than replacing the full-thickness cornea with the traditional penetrating keratoplasty. This has resulted in improved outcomes and the risk of endothelial rejection has reduced drastically, thus expanding the survival time of the graft. In recent years, reports of graft rejection in component keratoplasty have emerged, with each having a different presentation and responding to a different line of treatment. This review aims to summarize the presentation, diagnosis, and management of graft rejections in component keratoplasty.

Carlos Lisa,1,* Ricardo Machado Soares,2,* Luis Fernández-Vega-Cueto,1 Belén Alfonso-Bartolozzi,1 Jose F Alfonso1 1Cornea and Lens Department, Fernández-Vega Ophthalmological Institute, Oviedo, Spain; 2Department of Ophthalmology, Centro Hospitalar de Vila Nova de Gaia e Espinho, Porto, Portugal*These authors contributed equally to this workCorrespondence: Ricardo Machado Soares, department of Ophthalmology, Centro Hospitalar de Vila Nova de Gaia e Espinho, Rua Conceição Fernandes, S/N, Vila Nova de Gaia, Porto, 4434-502, Portugal, Tel +35 1915045174, Email Ricardo.machado.soares@chvng.min-saude.ptPurpose: To describe a modified deep anterior lamellar keratoplasty (DALK) technique to rescue failed penetrating keratoplasty (PK) grafts and report its results.Patients and Methods: Retrospective, case-series analysis of patients who underwent modified DALK to rescue failed corneal grafts after PK was included. Every patient had corneal graft failure (GF) diagnosis due to anterior corneal (epithelium, Bowman’s, and stroma layers) or refraction disorders uncorrectable with conservative management. The main objective of the surgery and primary outcome of the study was the improvement of corrected distance visual acuity (CDVA). The study’s secondary outcome was the frequency of intra- and postoperative complications.Results: This series included four eyes from three patients with a mean age of 57.7 years (range: 51– 63 years). Mean follow-up of patients was thirteen months (range: 12– 15 months). During follow-up, continuous improvement of corneal transparency and CDVA was observed in every patient. The only intraoperative complication reported was a peripheric DM microperforations of previous graft–host junction in two eyes. No signs of double anterior chamber, endothelial failure, GF, glaucoma, or other side effects were reported.Conclusion: Our results suggest that modified DALK in patients with GF after PK, preserving a healthy endothelium, is surgically feasible. However, further studies are needed to compare this procedure to PK and other DALK technique variations.Keywords: corneal transplantation, lamellar keratoplasty, graft failure, corneal diseases

Among the various indications for keratoplasty, failed graft is one of the commonest indications in many published series. It is well known that the major cause of graft failure is endothelial rejection. In the last two decades, there has been a major paradigm shift in the surgical management of corneal diseases, and component keratoplasty has emerged from the concept of replacing the layer that is actually diseased, rather than replacing the full-thickness cornea with the traditional penetrating keratoplasty. This has resulted in improved outcomes and the risk of endothelial rejection has reduced drastically, thus expanding the survival time of the graft. In recent years, reports of graft rejection in component keratoplasty have emerged, with each having a different presentation and responding to a different line of treatment. This review aims to summarize the presentation, diagnosis, and management of graft rejections in component keratoplasty. [ABSTRACT FROM AUTHOR]

Objective: Comparing results of two different DALK surgery techniques (big bubble vs. Melles) in patients with advanced keratoconus. Design: a retrospective comparative clinical study. Participants: This study conducted on 72 eyes of 72 participants. Introduction: This study designed to compare the results of two different DALK surgery techniques (big bubble vs. Melles) in patients with advanced keratoconus. Method: Thirty-seven eyes were treated using the big bubble DALK method, while 35 eyes were treated using the Melles approach. Uncorrected visual acuity (UCVA), best corrected spectacle visual acuity (BCSVA), manifest refraction, keratometric characteristics, contrast sensitivity, corneal aberrations, corneal biomechanical characteristics, and endothelial cell profile are the outcome measurements. Results: Mean UCVA in big bubble group was 0.61 ± 25 LogMAR and in Melles group was 0.89 ± 0.41 LogMAR (p-value 0.043). Mean BCSVA in big bubble group (0.18 ± 0.12 Log MAR) was significantly better than Melles group (0.35 ± 0.16 Log MAR). Mean of sphere and cylinder refraction showed no significant difference between two groups. Comparing the endothelial cell profile, corneal aberrations, corneal biomechanical properties and keratometry had no significantdifferences. Contrast sensitivity reported as modulation transfer function (MTF) showed higher values in big bubble group and differences with Melles group weresignificant. Results of point spread function (PSF) in big bubble group had superiority to Melles group with considerable statistical P value of 0.023. Conclusion: When opposed to the Melles approach, the big bubble technique generates a smooth interface with less stromal residue, which results in higher visual quality and contrast sensitivity. [ABSTRACT FROM AUTHOR]

Purpose: Evaluating the learning curve of individual surgeons for Descemet Membrane Endothelial Keratoplasty (DMEK) and Triple-DMEK and assessing outcome with experience. Methods: The first 41 and the last 41 surgeries of each of the four surgeons were retrospectively included. Surgery duration and graft preparation time were recorded. Corrected distance visual acuity (CDVA, logMAR) and central corneal thickness (CCT, µm) were collected preoperatively after 6 and 12 months, as well as postoperative complications, e.g., re-bubbling or repeat penetrating keratoplasty. Results: Surgical duration for Triple-DMEK and DMEK decreased significantly by 21 min and 14 min between the two periods (p < 0.001; p < 0.001). Graft preparation time decreased significantly from 13.3 ± 5.2 min (95%CI 12.8–14.3) in period 1 to 10.7 ± 4.8 min (95%CI 10.2–11.4) in period 2 (p = 0.002). The postoperative changes in CDVA and CCT over both periods were not significant (p = 0.900; p = 0.263). The re-bubbling rate decreased significantly from 51.2% in period 1 to 26.2% in period 2 (p < 0.001). The repeat penetrating keratoplasty (PKP) was 7.3% in period 1 and 3.7% in period 2 (p = 0.146). Re-DMEK was necessary in 6.1% in period 1 and 4.9% in period 2 (p = 0.535). Several parameters showed significant differences between the surgeons in both periods (surgical duration: period 1: p < 0.001, period 2 p < 0.001; graft preparation: period 1: p < 0.001, period 2 p < 0.001). Conclusion: Significant decrease in surgery duration, graft preparation time, and the re-bubbling rate can be attributed to gained individual experience. [ABSTRACT FROM AUTHOR]

According to the advantages of ultrasonic vibration cutting, an ultrasound-assisted corneal trepanation robotic system is developed to improve the accuracy of corneal trephination depth and corneal incision quality in corneal trephination operations. Firstly, we analyzed the reasons for the difficulty in controlling the depth of trephination in corneal transplantations from the perspective of the biomechanical properties of the cornea. Based on the advantages of ultrasonic vibration cutting, we introduced an ultrasonic-vibration-assisted cutting method for corneal trephination and analyzed the cutting mechanism. Secondly, we described the surgical demands of corneal trephination and listed the design requirements of a robotic system. Thirdly, we introduced the design details of said system, including the system's overall structure, the ultrasound-assisted end effector, the key mechanisms of the robotic system, and the human–machine interaction interface. We designed the end effector based on ultrasonic vibration cutting and its eccentric adjustment system in an innovative way. Additionally, we then presented a procedure for robot-assisted corneal trephination. Finally, we performed several cutting experiments on grapes and porcine eyeballs in vitro. The results show that, compared with manual trephine, ultrasound-assisted corneal trephination has a better operation effect on the accuracy of corneal trephination depth and corneal incision quality. [ABSTRACT FROM AUTHOR]

Mooren's ulcer (MU) is a chronic and painful ulcerative keratitis that is difficult to diagnose, especially when concealed beneath the pterygium, which is a common, benign, wedge-shaped, fleshy tissue growth of the conjunctiva extending onto the cornea. The coexistence of MU and pterygium is extremely rare. A 41-year-old man presented with a 2-month history of unprovoked redness, pain, and blurred vision in the right eye. Corneal epithelial defects around the pterygium head were noted upon slit-lamp examination and fluorescein staining. The patient was initially misdiagnosed with a corneal epithelial defect and pterygium. The initial treatments with anti-inflammatory and corneal epithelial growth promotion tear agents failed. Anterior segment optical coherence tomography (AS-OCT) showed corneal stromal lysis thinning, and in vivo confocal microscopy (IVCM) revealed marked inflammatory cell infiltration and stromal degeneration. We suspected the pathology was an immune-related or tumor-related corneal ulcer. The MU concealed beneath the pterygium was diagnosed by histopathological examination of a biopsy specimen that presented typical localized loss of the corneal epithelium and Bowman's layer, stromal degeneration, and inflammatory cell infiltration. Finally, we performed lamellar keratoplasty (LKP) combined with pterygium excision surgery. The patient recovered with no complications or recurrence during the 1-year follow-up period. Few cases of MU concealed beneath the pterygium have been reported. It is beneficial to rule out the pathological changes concealed beneath the pterygium, combined with multiple means of examination such as slit-lamp examination, AS-OCT, and IVCM. A histopathological examination should be performed to establish a diagnosis. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the repeat corneal transplantation trend in France from 2004 to 2019. Methods: Review of the prospectively compiled French Biomedicine Agency electronic database containing all corneal transplantation records from 2004 to 2019. The surgical technique, demographic characteristics, diagnosis, and previous graft data were retrieved and analyzed using the Cochran-Armitage trend test. Results: A total of 66,584 corneal transplantations were performed, 51,260 of which were first grafts and 15,324 (23%) were regrafts. For regrafts, 77% were penetrating keratoplasties (PK) and 19.6% were lamellar keratoplasties (LK). Age, hypertonia, glaucoma, trauma, lens surgery, immune disorders, diameter > 8.5 mm, and neovessels in > 2 quadrants were associated with a higher rate of repeat keratoplasty. Keratoconus, secondary endothelial dystrophy, and Fuchs' dystrophy were the principal indications for regrafting. When a previous graft failed, it occurred earlier for patients with LK (4.6 years, median = 2, SD = 7.54) than PK (8.48 years, median = 5, SD = 9.51). Failure within a year was the reason why 28.3% of the LK regrafts and 12.5% of PK regrafts were performed, while for failure within two years these values were 49.9% and 27.8%, respectively. Graft survival decreased with the number of repeat keratoplasty, being more pronounced after a second LK regraft and after a first PK regraft. Conclusion: The number of LK regrafts increased continuously, and 1/3 were performed for failure within the year. This rate increased until 2015, after which it stabilized until 2019, probably due to the better mastery of the technique. [ABSTRACT FROM AUTHOR]

Objective: Evaluate the effects of corneoconjunctival transposition (CCT), posterior lamellar keratoplasty (PLK) and modified deep lamellar endothelial keratoplasty (DLEK) on streak retinoscopy in equine cadaver eyes. Methods: Intraocular pressure (IOP) was maintained at 25 ± 3 mmHg in 35 equine cadaver eyes. Streak retinoscopy was performed prior to (NO VISCO) and following (VISCO) intracameral injection of 1.0 ml of viscoelastic. Following optical coherence tomography (OCT), an axial CCT [n = 11] or PLK [n = 12], or peripheral DLEK [n = 12] was performed. Streak retinoscopy and OCT were repeated postoperatively. Results: Postsurgical net meridional and spherical refraction for CCT [Horizontal (H): 3.4 (95% CI 2.4–4.4) diopters (D), p <.001, Vertical (V): 3.5 (95% CI 2.7–4.4) D, p <.001, Spherical: 3.5 (95% CI 2.6–4.3) D, p <.001] and PLK [H: 3.2 (95% CI 2.2–4.1) D, p <.001, V: 2.8 (95% CI 2.0–3.6) D, p <.001, Spherical: 3.0 (95% CI 2.2–3.8) D, p <.001] were significantly increased from presurgical (VISCO) values. No difference between presurgical (VISCO) and postsurgical values were identified for the DLEK. Postoperative OCT revealed space between anterior and posterior corneal grafts and corneal undulation associated with suture placement. Conclusion: Meridional and spherical refraction had a hyperopic shift following CCT and PLK, with a significantly higher value in the vertical meridian for the CCT. Pre‐ and postoperative refraction was not significantly different for the DLEK. This supports that the DLEK has a lesser effect on immediate postoperative refraction compared with CCT or PLK. [ABSTRACT FROM AUTHOR]

Introduction: Deep anterior lamellar keratoplasty is a surgical procedure for removing the corneal stroma down to Descemet's membrane. It is most useful for the treatment of corneal disease in the setting of a normally functioning endothelium. Materials and Methods: Patients attending Sarojini Devi Eye Hospital were screened. Twenty-eight eyes of 23 patients with anterior corneal pathologies and who had a best-corrected visual acuity of less than 6/60 and not improving beyond it were included in the study. Results: Conditions in which the pathology is limited to the anterior stroma and sparing the endothelium, lamellar keratoplasty as a procedure offers many advantages with fewer risks of complications. Conclusion: Corneal pathologies involving anterior stroma are better treated with DALK with fewer complications.

Limbal dermoid is a congenital benign tumor of the limbus which is often managed by surgery if necessary. In dermoid lesions involving the deep stroma, tumor excision and reconstruction of the anterior segment with amniotic membrane transplantation or keratoplasty may be required. Herein, we present a case of deep limbal dermoid treated with surgical resection and lamellar keratoplasty using microkeratome-assisted anterior lamellar graft. [ABSTRACT FROM AUTHOR]

Background: Posterior lamellar keratoplasty and especially Descemet membrane endothelial keratoplasty (DMEK) are gaining interest worldwide. Little is known about the influence of donor factors on DMEK outcome. Here we provide an overview of the existing peer-reviewed literature on this topic and present the design of the upcoming cooperation study COMEDOS (Cologne-Mecklenburg-Vorpommern DMEK Donor Study). Methods: A literature search of PubMed and MEDLINE was conducted to retrieve articles published between September 2013 and May 2021. Seventeen peer-reviewed articles were selected. Design and concept of the prospective COMEDOS are outlined. Results: Main interest parameters were the donor diabetes mellitus status, age, and lens status. There is a large heterogeneity regarding the sample size, study design, and investigated parameters. There seems to be a consensus that younger donors are associated with tighter rolls, a more difficult preparation, and unfolding setting. Diabetic donors seem to increase the risk of tissue tearing due to adherences and result more frequently in preparation failure. The COMEDOS aims not only to analyze the diabetes status of the donor, but also to correlate all donor systemic comorbidities and their ophthalmologic history to the DMEK clinical outcome. Furthermore, a correlation of Descemet membrane lamella preparation and surgery outcome is planned. Conclusion: Currently, there is a lack of knowledge regarding the effect and impact of donor tissue characteristics on DMEK outcome and complications. An in-depth investigation is planned by the upcoming COMEDOS to close this knowledge gap. [ABSTRACT FROM AUTHOR]

Widespread adoption of modern lamellar procedures has altered the pattern of practice of corneal transplantation. Herein, we describe recent findings from the Australian Corneal Graft Registry and place these data into an international context. The total number of grafts reported to the Registry has doubled over the past decade. Deep anterior lamellar keratoplasty is increasingly used for keratoconus, while endokeratoplasty has displaced penetrating keratoplasty for Fuchs endothelial dystrophy. Graft survival and visual outcomes for modern lamellar procedures have shown improvement over time. First deep anterior lamellar and penetrating grafts for keratoconus show comparable survival and long‐term best‐corrected visual acuity is equivalent. Penetrating grafts for Fuchs endothelial dystrophy exhibit significantly better survival than do endokeratoplasties, largely because the latter undergo more early graft failures. However, visual rehabilitation is swifter in surviving endokeratoplasties. Significantly fewer recipients of a deep anterior lamellar graft or endokeratoplasty require spectacle or contact lens correction, compared with penetrating keratoplasty. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to assess the results, rebubbling rate, and graft survival after Descemet membrane endothelial keratoplasty (DMEK) with regard to the number and type of previous glaucoma surgeries. Methods: This is a clinical retrospective review of 1845 consecutive DMEK surgeries between 07/2011 and 08/2017 at the Department of Ophthalmology, University of Cologne. Sixty-six eyes were included: group 1 (eyes with previous glaucoma drainage devices (GDD); n = 27) and group 2 (eyes with previous trabeculectomy (TE); n = 39). Endothelial cell loss (ECL), central corneal thickness, graft failure, rebubbling rate, and best spectacle-corrected visual acuity (BSCVA) up to 3 years after DMEK were compared between subgroups of patients with different numbers of and the two most common types of glaucoma surgeries either GDD or TE or both. Results: Re-DMEK rate due to secondary graft failure was 55.6% (15/27) in group 1 and 35.9% in group 2. The mean graft survival time in group 1 was 25 ± 11 months and 31.3 ± 8.6 months in group 2 (p = 0.009). ECL in surviving grafts in group 1 was 35% (n = 13) at 6 months, 36% at 12 months (n = 8), and 27% (n = 4) at 2 years postoperatively. In group 2, ECL in surviving grafts was 41% (n = 10) at 6 months, 36% (n = 9) at 12 months, and 38% (n = 8) at 2 years postoperatively. Rebubbling rate in group 1 was 18.5% (5/27) and 35.9% (14/39) in group 2 (p = 0.079). Conclusion: Eyes with previous GDD had no higher risk for an increased rebubbling rate but a higher risk for a re-DMEK due to secondary graft failure with a mean transplant survival time of about 2 years. Compared to eyes with preexisting glaucoma drainage device, eyes after trabeculectomy had less secondary graft failures and a longer mean graft survival rate. [ABSTRACT FROM AUTHOR]

Ahmad AlAraj,1,2 Ahmad AlAmeer,1,3 Samar Al-Swailem1 1Anterior Segment Division, Department of Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Kingdom of Saudi Arabia; 2Department of Ophthalmology, College of Medicine, Qassim University, Qassim, Saudi Arabia; 3Ophthalmology Division, Surgery Department, King Abdullah bin Abdulaziz University Hospital, Riyadh, Saudi ArabiaCorrespondence: Samar Al-SwailemAnterior Segment Division, Department of Ophthalmology, King Khaled Eye Specialist Hospital, P.O. Box 7191, Riyadh, 11462, Kingdom of Saudi ArabiaTel +966-11-482-1234 ext.1152Email angelofsa@yahoo.comPurpose: To compare the postoperative outcomes of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) for macular corneal dystrophy (MCD).Design: Single-center, retrospective, interventional case series.Methods: A chart review was performed of 100 patients (157 eyes) who underwent primary DALK (DALK group) and PKP (PKP group) for histopathologically confirmed MCD for whom at least 12 months of follow-up were available. Between-group comparisons were performed of visual acuity (VA), graft survival, and postoperative complications.Results: There were 22 eyes in the DALK group and 135 in the PKP group. Postoperative best-corrected visual acuity (BCVA) of 20/40 or better was achieved in 90.9% of the DALK group and 76.3% of the PKP group (P=0.12). At last visit, graft survival was 95.5% (21 eyes) and 91.1% (123 eyes) in DALK and PKP groups, respectively (P=0.69, Log rank test). Corneal graft rejection episodes occurred in 1 (4.5%) DALK graft and 19 (14.1%) PKP grafts. Five of the 19 graft rejections in the PKP group were irreversible. Microbial keratitis and cataract occurred in 6 (4.5%) and 15 (11.1%) PKP eyes. One (4.5%) eye in the DALK group had cataract and none of the DALK cases developed microbial keratitis. Clinically significant recurrence was observed in 4 (2.9%) PKP eyes and 1 (4.5%) DALK eye (P=0.69), respectively.Conclusion: DALK is a viable option for MCD without Descemet membrane involvement. DALK had comparable medium-term visual and survival outcomes to PKP. DALK has the advantage of lower open sky intraoperative complications and lower graft rejection episodes.Keywords: macular corneal dystrophy, keratoplasty, lamellar keratoplasty, penetrating keratoplasty

Yingxin Chen, Linlin Zhang, Zhiling Liu, Qiming Liu, Minghong Gao Department of Ophthalmology, General Hospital of Northern Theater Command, Shenyang, People’s Republic of ChinaCorrespondence: Minghong GaoDepartment of Ophthalmology, General Hospital of Northern Theater Command, 83 Wenhua Road, Shenhe District, Shenyang, 110840, People’s Republic of ChinaTel +86-133-5245-9433Email gaominghong88@yeah.netBackground: The aim of this study was to investigate the efficacy of acellular porcine corneal stroma (APCS) transplantation in the treatment of infectious central and peripheral corneal ulcers.Methods: A total of 45 patients with infectious corneal ulcers who had undergone lamellar keratoplasty using APCS grafts were included. Among these, 24 had lesions located near the pupil (infectious central corneal ulcer group) and 21 had lesions located in the limbus or around the cornea (infectious peripheral corneal ulcer group). Efficacy was assessed in terms of best-corrected visual acuity, graft transparency, corneal neovascularization, corneal reepithelialization, survival rate, and postoperative complications.Results: Baseline characteristics showed that poor visual acuity and larger-diameter APCS graft in the infectious central corneal ulcer group were comparable with the infectious peripheral corneal ulcer grouper group (P< 0.05). After lamellar keratoplasty using APCS grafts, no obvious differences were observed in aspects of graft transparency, corneal neovascularization, or survival rate (P> 0.05). Postoperative complications, ie, delayed corneal epithelial healing, rejection episode, recurrence of infection, and graft melting, were not significantly different between the two groups (P> 0.05). Visual acuity in bothgroups had improved significantly at 3 months and 6 months postoperation, respectively.Conclusion: APCS transplantation is safe and efficacious for treating infectious central and peripheral corneal ulcers. Despite its good efficacy, APCS-graft size, implant position, patient indications, and postoperative management should be kept in mind in treatment for infectious corneal ulcers in different locations.Keywords: acellular porcine corneal stroma, lamellar keratoplasty, infectious central corneal ulcers, infectious peripheral corneal ulcers

Purpose: To evaluate the clinical results of a combined approach to the treatment of pellucid marginal degeneration, that includes femtolaser-assisted keratotomy, intrastromal lamellar keratoplasty with a use of refractive lenticule and a simultaneous intracorneal ring segment implantation, followed by a local collagen cross-linking.Patients and methods. An analysis of the outcomes of the surgical treatment performed in 20 eyes of 15 patients from 36 to 57 years old who were diagnosed with pellucid marginal degeneration in both of their eyes. During the first stage of the treatment patients underwent a femtolaser-assisted keratotomy in a steep meridian, intrastromal lamellar keratoplasty in the zone of corneal thinning and a simultaneous implantation of intracorneal ring segments with an arc-length of 80 to 160 degrees, followed by a local corneal cross-linking during the second stage. Refractive lenticules obtained during the ReLEx® SMILE procedure were used as a lamellar graft.Results. By the end of the follow-up period of 12 months the UCVA had improved from 0.1 ± 0.07 to 0.33 ± 0.23 and the BCVA from 0.4 ± 0.25 to 0.7 ± 0.28 (p < 0.05). The corneal topography demonstrated a decrease in maximum simulated keratometry values from 49.28 ± 2.57 D to 46.15 ± 1.73 D and an astigmatism reduction from 7.4 ± 3,9 D to 2.1 ± 0,53 D. The corneal thickness increased from 508.0 ± 31.0 μm to 606.0 ± 36.0 μm in the zone of the thinning.Conclusions. The analysis of the clinical outcomes has demonstrated the high efficacy of the combined approach to the treatment of pellucid marginal degeneration. The ICRS implantation allowed for a significant cylinder reduction and an improvement of visual acuity. The lamellar keratoplasty allowed for a reinforcement of the thinned cornea, and the subsequent local collagen cross-linking ensured corneal stability.

According to the advantages of ultrasonic vibration cutting, an ultrasound-assisted corneal trepanation robotic system is developed to improve the accuracy of corneal trephination depth and corneal incision quality in corneal trephination operations. Firstly, we analyzed the reasons for the difficulty in controlling the depth of trephination in corneal transplantations from the perspective of the biomechanical properties of the cornea. Based on the advantages of ultrasonic vibration cutting, we introduced an ultrasonic-vibration-assisted cutting method for corneal trephination and analyzed the cutting mechanism. Secondly, we described the surgical demands of corneal trephination and listed the design requirements of a robotic system. Thirdly, we introduced the design details of said system, including the system’s overall structure, the ultrasound-assisted end effector, the key mechanisms of the robotic system, and the human–machine interaction interface. We designed the end effector based on ultrasonic vibration cutting and its eccentric adjustment system in an innovative way. Additionally, we then presented a procedure for robot-assisted corneal trephination. Finally, we performed several cutting experiments on grapes and porcine eyeballs in vitro. The results show that, compared with manual trephine, ultrasound-assisted corneal trephination has a better operation effect on the accuracy of corneal trephination depth and corneal incision quality.

Intraoperative optical coherence tomography (iOCT) is a noninvasive imaging technique that gives real-time dynamic feedback on surgical procedures. iOCT was first employed in vitreoretinal surgery, but successively served as a guidance in several anterior segment surgical approaches: keratoplasty, implantable Collamer lens (ICL) implantation, and cataract surgery. Among all of those approaches, the unbeatable features of iOCT are fully exploited in anterior and posterior lamellar keratoplasty, and the purpose of this review is to focus on the advantages and shortfalls of iOCT in these techniques, in order to assess whether this technology could be a real step forward. In deep anterior lamellar keratoplasty (DALK), iOCT is useful to evaluate the needle depth into the corneal stroma, the big bubble dissection plane, and residual stromal bed, thus aiding the standardization of the technique and the reduction of failures. In Descemet stripping automated endothelial keratoplasty (DSAEK), iOCT allowed for clear visibility of fluid at the graft/host interface, allowing for immediate rescue maneuvers and granting the best graft apposition. In Descemet membrane endothelial keratoplasty (DMEK), iOCT can track the lenticule unfolding in real time and assess graft orientation even in severe hazy corneas, thus optimizing surgical times, as well as avoiding the use of potentially hazardous exterior markers (such as the "S" stamp) and preventing unnecessary manipulation of the graft. Overall, the role of iOCT appeared crucial in several complicated cases, overcoming the difficulties of poor visualization in a fast, non-invasive way, thus raising this approach as possible gold standard for challenging conditions. Further improvements in the technology may enable autonomous centering and tracking, overcoming the current constraint of instrument-induced shadowing. [ABSTRACT FROM AUTHOR]

Purpose: To describe the corneal calcification of acellular porcine corneal stroma (APCS) following lamellar keratoplasty (LKP) and identify risk factors. Methods: Two cases of APCS calcification were evaluated by slit‐lamp photography and anterior segment optical coherence tomography (AS‐OCT). von Kossa staining and scanning electron microscope/energy‐dispersive spectrometry (SEM/EDS) were performed on pathologic tissue. Associated graft and postoperative risk factors were analysed. Acellular porcine corneal stroma (APCS) cleanliness and element content after rinsing with sterilized water were observed by SEM/EDS and inductively coupled plasma mass spectrometry. Calcium metabolism‐related proteins were analysed by protein mass spectrometry. Corneal epithelial defects and postoperative medications were reviewed. Results: Two cases of APCS calcification occurred at 23 and 22 days postoperatively. Anterior segment optical coherence tomography (AS‐OCT) and von Kossa staining demonstrated calcium deposition in the superficial stroma composed of calcium, phosphorus and oxygen conforming to the Ca/P ratio of hydroxyapatite. Phosphate crystals were present on the APCS surface and decreased with number of rinsing times. The phosphorus content of APCS was minimal after rinsing 10 times and avoiding excessive corneal swelling. Calcium metabolism‐related proteins were downregulated in APCS. Patients with corneal calcification had 1‐week postoperative corneal epithelial defects and were treated with three types of phosphorous eyedrops. Conclusions: Acellular porcine corneal stroma (APCS) calcification occurs in the superficial corneal stroma about 1 month after LKP. The application of AS‐OCT, von Kossa staining and SEM/EDS provides a basis for the clinical and pathological diagnosis of corneal calcification. The associated risk factors were mainly high phosphorus content and downregulated calcium metabolism‐related proteins in APCS. Postoperative epithelial defects, inflammation and use of phosphorous eyedrops may promote corneal calcification. [ABSTRACT FROM AUTHOR]

Introduction: Deep anterior lamellar keratoplasty is a surgical procedure for removing the corneal stroma down to Descemet's membrane. It is most useful for the treatment of corneal disease in the setting of a normally functioning endothelium. Materials and Methods: Patients attending Sarojini Devi Eye Hospital were screened. Twenty-eight eyes of 23 patients with anterior corneal pathologies and who had a best-corrected visual acuity of less than 6/60 and not improving beyond it were included in the study. Results: Conditions in which the pathology is limited to the anterior stroma and sparing the endothelium, lamellar keratoplasty as a procedure offers many advantages with fewer risks of complications. Conclusion: Corneal pathologies involving anterior stroma are better treated with DALK with fewer complications. [ABSTRACT FROM AUTHOR]