Autologous Contralateral and Ipsilateral Rotational Penetrating Keratoplasty - A Case Series and Mini-Review.

Corneal stromal opacities can severely impact visual acuity if they are located in the visual axis. Homologous penetrating keratoplasty (HPK) is usually the preferred surgical option in such clinical circumstances. However, autologous penetrating keratoplasty (APK) could be an immunologically safer alternative. The purpose of this study was to report the surgical technique, indications, and (dis)advantages of ipsilateral rotational and contralateral APK, as well as pre- and postoperative clinical findings of four patients who underwent contralateral APK. In ipsilateral rotational APK, eccentric trephination places the central corneal opacity at the excision edge, whereafter the corneal button is rotated to clear the visual axis. Contralateral APK is suitable for more specific clinical situations with corneal opacity in a functionally much better eye. Clear cornea of the (almost) blind eye suffering from a noncorneal pathology is transplanted to the potentially better seeing eye suffering from a corneal pathology, followed by HPK in the (almost) blind donor eye. After 18 months, potentially better-seeing eyes improved from logMAR 1.3 to 0.6 in visual acuity, with most HPK-treated weaker eyes matching preoperative levels. Considering ipsilateral rotational and contralateral APK before moving on straight towards HPK is crucial in select cases. Autologous contralateral keratoplasty should be preferred for patients with (1) corneal scars in a potentially better seeing eye and (2) a clear cornea in an (almost) blind eye, especially in cases of high risk for graft rejection.

Excimer Laser-Assisted Deep Anterior Lamellar Keratoplasty Versus Penetrating Keratoplasty for Patients With Keratoconus: A Retrospective Analysis From the Homburg Keratoconus Center.

PURPOSE: To evaluate the outcome of excimer laser-assisted deep anterior lamellar keratoplasty (Exc-DALK) and penetrating keratoplasty (Exc-PKP) for keratoconus (KC). METHODS: We included 123 eyes and compared the outcome of 30 eyes undergoing big-bubble Exc-DALK after stromal debulking (G1) against a matched group of 83 eyes undergoing Exc-PKP (G2) in our department. G2 was created after performing a pseudorandom stratified bootstrapping of our PKP database starting with 2802 surgeries with removal of any bias. Main outcomes included best corrected visual acuity (BCVA), spherical equivalent (SE), tomographic changes, and endothelial cell density (ECD). Data were compared preoperatively, postoperatively with 2 double-running cross-stitch sutures according to Hoffmann [2 and 10 months postoperatively (T1 and T2)], after first suture removal [15 months postoperatively (T3)], and after final suture removal [26 months postoperatively (T4)]. RESULTS: Preoperatively, all parameters were comparable without significant differences. At T1, G1 showed significantly better BCVA (P = 0.01), lower SE (P = 0.04), lower anterior and posterior topographic astigmatism (ATA and PTA, P < 0.01), lower maximal keratometry (P = 0.02), and lower central corneal thickness (P < 0.01). At T2, G1 showed significantly better BCVA (P = 0.04), lower PTA (P < 0.01), and higher ECD (P < 0.01). At T3, G1 showed significantly lower ATA (P = 0.01) and PTA (P < 0.01) and higher ECD (P = 0.02). At T4, G1 showed significantly lower PTA and higher ECD (P < 0.01) but no significant difference in BCVA (P = 0.07). CONCLUSIONS: Exc-DALK provided faster visual rehabilitation and represented an endothelial cell-sparing method compared with Exc-PKP. After final suture removal, Exc-DALK showed noninferior outcomes compared with Exc-PKP if the graft was placed on naked Descemet membrane.

Rethinking Keratoplasty for Patients with Acanthamoeba Keratitis: Early "Low Load Keratoplasty" in Contrast to Late Optical and Therapeutic Keratoplasty.

BACKGROUND: Early therapeutic penetrating keratoplasty (TKP) for Acanthamoeba keratitis (AK) is thought to have a worse visual prognosis than the delayed optical penetrating keratoplasty (OKP) after successful conservative treatment of AK. This has led to a tendency to prolong conservative therapy and delay penetrating keratoplasty in patients with AK. This retrospective series presents the results of patients with AK that underwent early penetrating keratoplasty after reducing the corneal amoeba load through intensive conservative therapy, so-called "low load keratoplasty" (LLKP). PATIENTS AND METHODS: The medical records of our department were screened for patients with AK, confirmed by histological examination and/or PCR and/or in vivo confocal microscopy, which underwent ab LLKP and had a follow-up time of at least one year between 2009 and 2023. Demographic data, best corrected visual acuity (BCVA) and intraocular pressure at first and last visit, secondary glaucoma (SG), and recurrence and graft survival rates were assessed. RESULTS: 28 eyes of 28 patients were included. The average time from initiation of therapy to penetrating keratoplasty (PKP) was 68 ± 113 days. The mean follow-up time after LLKP was 53 ± 42 months. BCVA (logMAR) improved from 1.9 ± 1 pre-operatively to 0.5 ± 0.6 at last visit (p < 0.001). A total of 14% of patients were under medical therapy for SG at the last visit, and two of them underwent glaucoma surgery. The recurrence rate was 4%. The Kaplan-Meier graft survival rate of the first graft at four years was 70%. The second graft survival rate at four years was 87.5%. CONCLUSION: LLKP appears to achieve a good visual prognosis with an earlier visual and psychological habilitation, as well as low recurrence and SG rates. These results should encourage us to reconsider the optimal timing of PKP in therapy-resistant AK.

Outcomes of manual arcuate keratotomy with compression sutures for high regular postkeratoplasty astigmatism.

PURPOSE: To report functional and refractive outcomes of manual arcuate keratotomy (AK) with compression sutures for high regular postkeratoplasty astigmatism.Setting: not specified (review). DESIGN: Retrospective analysis. METHODS: This study included 90 eyes with high regular postkeratoplasty astigmatism (>4 diopters, D) who received AK with compression sutures between 2010 and 2022. Functional and refractive outcomes were assessed by evaluating topographic indices and by performing vector astigmatism and Fourier analysis. RESULTS: At last follow-up (mean=13.7±16.6 months), BCDVA improved from 0.59±0.28 logMAR to 0.34±0.25 logMAR. Cylinder magnitude decreased from 9.91±2.88 D to 5.42±3.35 D. Surface Asymmetry Index, Irregular Astigmatism Index, Corneal Eccentricity Index were equal to preoperative values, whereas Surface Regularity Index approached normal values at last follow-up. Fourier analysis indicated a decrease in the regular astigmatic component, whereas non-regular components (asymmetry and higher-order irregularity) remained stable. In vector astigmatism analysis, Target Induced Astigmatism magnitude was 9.92±2.86 D and Surgically Induced Astigmatism magnitude was 10.16±4.86 D (Correction Index of 0.91±0.48) with a Difference Vector of 5.42±3.35 D at last follow-up. Correction of astigmatism magnitude was adequate in 40% of the eyes, under-corrected in 30% and over-corrected in 30%. Angle of Error was <|22.5°| in 88% resulting in a low risk of off-axis treatment. CONCLUSION: AK with compression sutures is a simple, relatively effective and safe surgical procedure for astigmatism reduction after keratoplasty. In case of regular astigmatism, the procedure does not increase corneal irregularities. The remaining refractive error might be further corrected by spectacles, contact lenses or toric IOL implantation (in-the-bag / add-on), thus reducing the need for repeat keratoplasty.

Impact of Donor, Host, and Surgical Parameters on High Endothelial Cell Density More Than 5 Years after Penetrating Keratoplasty.

OBJECTIVES: To investigate the correlation between postoperative endothelial cell loss (ECL) and donor, host, and surgical parameters, and to assess the clinical impact of maintaining a high endothelial cell density (ECD) of ≥ 1500 cells/mm2 5 years after penetrating keratoplasty (PKP). METHODS: This retrospective cohort study included 216 eyes with 5 years of follow-up, of which 94 had annual visits, and who underwent normal-risk elective PKP for noninfectious indications by one corneal microsurgeon (B. S.) between 2009 and 2016. RESULTS: Among the 216 eyes, ECL (39.1%) over 5 years postoperative exhibited weak positive correlations with storage solution time (p = 0.024) and postmortem time (p = 0.028), and moderately positively correlations with the preoperative ECD (p < 0.001). The 5-year postoperative ECL differed significantly between in domo-prepared (36.8%) and ex domo donor corneas (46.3%; p = 0.001). In the 94 eyes, no significant differences were found between the two groups for central pupil pachymetry (CCT) and BCVA (p > 0.074). However, CCT increased significantly between 1 and 4 years (p = 0.034) and 1 and 5 years postoperatively (p = 0.012), respectively. BCVA improved significantly at 1 year postoperatively and continued to improve until 2 years postoperatively (p < 0.001). CONCLUSION: The Lions corneal bank Saar-Lor-Lux achieved a significantly reduced ECL (36.8%) over 5 years compared to ex domo donor corneas (46.3%). A weak positive correlation was found between ECL with the storage solution time and the postmortem time, as well as a moderate positive correlation with the preoperative ECD. Although CCT increased significantly over 5 years, BCVA improved significantly from the first to the second postoperative year and remained stable thereafter.

[Bacterial keratitis : Clinical aspects, pathogens and treatment]. / Bakterielle Keratitis : Klinische Aspekte, Erreger und Therapie.

Bacterial infections are by far the most frequent cause of infectious keratitis in high-income countries. The clinical appearance can vary widely depending on the type and species of bacteria, ranging from small superficial infiltrates to necrotizing forms. The numerous classes of available antibiotics render the treatment scope diverse and complex, especially before the pathogen has been specified and the sensitivity to antibiotics has been tested. New therapeutic approaches to reduce bacterial virulence are in development. This CME article focuses on the clinical, diagnostic and therapeutic approaches to recognize and treat bacterial keratitis.

Comparison of Scheimpflug Imaging (Pentacam HR) and Swept-Source Optical Coherence Tomography (CASIA2) in Eyes With Macular Corneal Dystrophy.

PURPOSE: Assessment of tomographic characteristics and interdevice comparability between Scheimpflug imaging (Pentacam HR, Oculus Optikgeräte GmbH, Wetzlar, Germany) and swept-source optical coherence tomography (CASIA2, Tomey Corp., Nagoya, Japan) in eyes with macular corneal dystrophy (MCD). METHODS: Eyes with MCD were examined by Pentacam HR and CASIA2. Interdevice comparison was performed using a Wilcoxon matched pairs test and Bland-Altman plots with 95% limit of agreement. A Spearman rank correlation coefficient was used for correlating indices of both devices. RESULTS: This retrospective study included 31 eyes of 18 patients (mean age: 32.1 ± 10.7 years). Eyes with MCD demonstrated a moderate astigmatism with a Cylinder anterior of 2.56 ± 1.50 D (Pentacam HR) and 2.52 ± 1.57 D (CASIA2) without a difference between both devices. CASIA2 (0.34 ± 0.14 D) measured lower values of Cylinder posterior compared with Pentacam HR (0.96 ± 0.66 D) (P < 0.0001). Comparison of pachymetry (Pentacam HR vs. CASIA2) showed higher values of the central corneal thickness (619 ± 227 µm vs. 445 ± 67 µm, P = 0.0001) and the thinnest corneal thickness (499 ± 165 µm vs. 430 ± 60 µm, P = 0.0167) for Pentacam HR. Corneal densitometry measurement revealed that increasing gray scale units caused a greater interdevice difference for pachymetry values, as Pentacam HR measured higher than CASIA2 for more opaque corneas. CONCLUSIONS: Eyes with MCD tend to have thinner corneas and a higher amount of corneal astigmatism than healthy eyes. In advanced MCD, Scheimpflug technology may mistakenly overestimate corneal thickness. The pachymetry measurement of the optical coherence tomography should be used when planning corneal surgery such as excimer laser-assisted phototherapeutic keratectomy to determine the ablation depth.

Subfoveal choroidal thickness increases after excimer laser-assisted penetrating keratoplasty but not after excimer laser-assisted deep anterior lamellar keratoplasty.

To evaluate the impact of excimer laser-assisted deep anterior lamellar keratoplasty (Exc-DALK) and excimer laser-assisted penetrating keratoplasty (Exc-PKP) on subfoveal choroidal thickness (SFCT) in eyes with advanced keratoconus. A retrospective comparative clinical study, which compares the outcomes of 24 eyes treated with Exc-DALK (G1) against matched group of 43 eyes treated with Exc-PKP (G2) at both 2 months (T1) and 2 years (T2) postoperatively. Main outcomes included best-corrected visual acuity (BCVA), central macular thickness (CMT), and SFCT. Preoperatively, there were no significant differences between both groups regarding BCVA, CMT or SFCT (p > 0.05). There were no significant differences between both groups regarding BCVA at both follow-ups (p > 0.05). There were no significant differences between both groups regarding CMT at both follow-ups (p > 0.05). SFCT was higher in G2 than G1 at both follow-ups (p < 0.01). Compared to preoperative SFCT, there were no significant changes in SFCT in G1 at both follow-ups (p > 0.05). In G2, SFCT increased significantly at T1 (p < 0.01) and did not differ significantly at T2 (p = 0.17). SFCT increased significantly after Exc-PKP but not after Exc-DALK, which might indicate that Exc-DALK affects the choroid less and thus could represent a less traumatic approach to ocular tissue than Exc-PKP.

Evaluation of dynamic corneal response parameters and the biomechanical E-staging after Intacs® SK implantation in keratoconus.

PURPOSE: This retrospective longitudinal study evaluated the biomechanical E-staging in KC corneas before and after intracorneal ring segment (ICRS) implantation (Intacs® SK, Addition Technology, Illinois, United States). METHODS: Biomechanical E-staging for ectatic corneal diseases was applied retrospectively on 49 KC corneas of 41 patients who underwent ICRS implantation. The main outcome parameters included the Corvis Biomechanical Factor (CBiF, the linearized Corvis Biomechanical Index and the biomechanical parameters included), the resulting biomechanical E-staging, the stress-strain index, thinnest corneal thickness (TCT), maximal anterior keratometry (Kmax), and the anterior radius of curvature (ARC). They were evaluated at 1.9 ± 1.1 months preoperatively and postoperatively after 2.8 ± 0.7, 5.8 ± 1.0, and 10.6 ± 2.3 months. RESULTS: The CBiF decreased (4.9 ± 0.5 | 4.7 ± 0.5, P = 0.0013), and the E-staging increased significantly (2.8 ± 0.8 | 3.1 ± 0.9, P = 0.0012, paired t-test) from preoperatively to the first postoperative follow-up. The difference remained significant after 6 months; however, there was no more difference after 11 months. TCT was stable, whereas Kmax and ARC significantly decreased after ICRS implantation (TCT: 464 ± 49, 470 ± 51, 467 ± 38, 461 ± 48; Kmax: 56.3 ± 4.5, 54.7 ± 4.5, 54.2 ± 4.8, 54.1 ± 4.3; ARC: 51.5 ± 3.4, 48.3 ± 3.8, 48.6 ± 3.0, 48.6 ± 3.2 preoperatively and 3, 6, and 11 months postoperatively, respectively). Besides Kmax and ARC, Ambrósio's relational thickness to the horizontal profile (ARTh) was the only parameter that was significantly lower than preoperatively at any follow-up (P ≤ 0.0024, Wilcoxon matched-pairs test). CONCLUSION: Intacs® SK implantation results in an increasing biomechanical E-staging in the first postoperative months with stabilization near preoperative values after 1 year. Significantly lower ARTh values at any follow-up document the ICRS effect and contribute to a slightly higher postoperative biomechanical E-staging value.

[Impact of the ratio between graft and host corneal size on immune rejection, re-bubbling rate and postoperative endothelial cell loss in 457 eyes after Descemet membrane endothelial keratoplasty (DMEK)]. / Einfluss des Verhältnisses von Transplantatgröße zu Hornhautgröße auf Immunreaktion, Re-Bubbling-Rate und postoperativen Endothelzellverlust bei 457 Augen nach Descemet-Membrane-Endothelial-Keratoplastik (DMEK).

BACKGROUND: The aim of this study was to assess the impact of the ratio between the graft and host corneal size (RGH) on postoperative complications, such as immune reactions, re-bubbling rate and endothelial cell loss (ECL) after Descemet membrane endothelial keratoplasty (DMEK). PATIENTS AND METHODS: Retrospectively, 457 patient eyes were included which had undergone surgery between 2016 and 2019 in the Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar using DMEK or triple DMEK, diagnosed as Fuchs' endothelial dystrophy (n = 431), pseudophakic bullous keratopathy (n = 9) and others (n = 17). The follow-up period extended until the end of 2020. Main outcome measures included immune reaction (IR), re-bubbling rate and the postoperative endothelial cell loss (ECL) at 6 weeks, 6 months and 12 months and whether these measures depended on the RGH. RESULTS: The RGH in this study ranged from 0.35 to 0.62 (0.46 ± 0.04). There were 33 (7.2%) postoperative IRs (DMEK n = 25; triple DMEK n = 8). The average RGH without IR (0.46 ± 0.04) was significantly (p = 0.038) smaller than in the group with IR (0.47 ± 0.05). Re-bubbling was necessary in 159 of 457 (34.8%) patient eyes. The RGH in patient eyes with re-bubbling (0.47 ± 0.04) was significantly (p = 0.014) higher than that in eyes without re-bubbling (0.45 ± 0.04). The mean preoperative endothelial cell count (ECD) was 2603 ± 251 cells/mm2 (min: 2161, max: 3500 cells/mm2). It was shown that a larger RGH had no positive influence on endothelial cell loss (r = 0.001; p = 0.974). CONCLUSION: Our results suggest that a larger graft diameter compared to host corneal size is associated with an increased rate of immune reactions and a higher re-bubbling rate after DMEK. Otherwise, a larger RGH had no positive influence on endothelial cell loss after DMEK. Accordingly, the graft size for DMEK should not be unnecessarily large, especially in eyes with Fuchs' endothelial dystrophy.

Review for special issue: Corneal lamellar surgery: Present outcomes and future perspectives.

Since the establishment of the first eye bank in the 1940s, their role has evolved to face new challenges. With the recent development of lamellar keratoplasties, eye banks play an even bigger role in the selection and preparation of donor tissues. The increasing number of keratoplasty techniques and the high demand for "ready-to-use" tissues are challenging eye banks to improve and develop new preparation techniques. Besides necessary examinations, new approaches of tissue analysis in eye banks allow a better/optimized selection of corneal tissues. These new challenges in tissue preservation, preparation, and selection are propelling eye banks into a new era of modern eye banking.

First-Year Real-Life Experience with Intravitreal Faricimab for Refractory Neovascular Age-Related Macular Degeneration.

Background: To evaluate the outcomes of intravitreal faricimab (IVF) for refractory neovascular age-related macular degeneration (nAMD) and investigate the impact of baseline optical coherence tomography, biomarkers for total IVF injections are needed. Methods: A retrospective analysis of 33 eyes of patients who completed one year (52 W) of treatment with IVF. The eyes received four IVF injections (6 mg/0.05 mL) as the upload phase. Thereafter, the treatment interval was extended to 8 or 12 weeks if disease activity was not recorded. The outcome measures included best-corrected visual acuity (BCVA), central macular thickness (CMT), subfoveal choroidal thickness (SFCT), and retinal fluid distribution. Results: A total of 33 eyes were included. CMT decreased significantly at 52 W (p < 0.01). BCVA and SFCT did not change significantly at 52 W (p > 0.05). The number of eyes with subretinal fluid decreased significantly at 52 W (p < 0.01). Complete fluid resolution was achieved in 20 eyes (60%). The total number of injections was significantly negatively correlated with the presence of hyperreflective dots at baseline (HRDs, p < 0.01) and SFCT at baseline (p < 0.01). Conclusions: IVF led to a significant reduction in CMT with stabilization of BCVA. The total number of injections was lower in eyes with HRDs and increased SFCT at baseline. This might provide clues regarding response to IVF for future studies.

Long-Term Follow-Up of Pediatric Excimer Laser-Assisted Penetrating Keratoplasty for Congenital Stromal Corneal Dystrophy.

PURPOSE: The purpose of this study was to highlight characteristic clinical and microscopic findings and report the long-term follow-up of pediatric excimer laser-assisted penetrating keratoplasty (excimer-PKP) for congenital stromal corneal dystrophy (CSCD). METHODS: A 2-year-old Greek child presented with CSCD at our department. Clinical examination showed bilateral flake-like whitish corneal opacities affecting the entire corneal stroma up to the limbus. Genetic testing identified a mutation of the decorin gene (c.962delA). The variant was not present in the parents and represented a de novo mutation. The uncorrected visual acuity was 20/100 in both eyes. Excimer-PKP (8.0/8.1 mm) was performed on the right eye at the age of 2.5 years and on the left eye at the age of 3 years. Postoperatively, alternating occlusion treatment was performed. RESULTS: The light microscopic examination demonstrated a disorganized extracellular matrix of the corneal stroma characterized by a prominent irregular arrangement of stromal collagen lamellae with large interlamellar clefts containing ground substance, highlighted by periodic acid-Schiff- and Alcian blue-positive reaction detecting acid mucopolysaccharides. Electron microscopy showed disorganization and caliber variation of collagen lamellae and thin filaments within an electron-lucent ground substance. The postoperative course was unremarkable. Both grafts remained completely clear 14 years postoperatively. Corneal tomography showed moderate regular astigmatism with normal corneal thickness. The corrected distance visual acuity was 20/25 in both eyes. CONCLUSIONS: Excimer-PKP for CSCD might be associated with excellent long-term results and a good prognosis, particularly when the primary surgery is performed at a very young age. However, this requires close postoperative follow-up examinations by an experienced pediatric ophthalmologist to avoid severe amblyopia.

Analysis of Graft Detachments and Re-Bubblings After 450 Descemet Membrane Endothelial Keratoplasty Procedures.

PURPOSE: To objectify the indication for re-bubbling by analyzing graft detachments (GDs) after Descemet membrane endothelial keratoplasty. METHODS: In this retrospective monocentric observational study, re-bubbling cases of 450 Descemet membrane endothelial keratoplasties and the percentage of the residual gas filling (RGF) in the anterior chamber on the first postoperative day were collected. The number/location/extent of GDs and the corneal thickness above GDs were analyzed using anterior segment optical coherence tomography. RESULTS: From a total of 450 grafts, 384 (85.3%) had at least a minimal degree GD. One hundred twenty-two of 450 grafts (27.1%) underwent at least 1 re-bubbling. The mean RGF was significantly lower in eyes with GD (67.7 ± 12.6%) than in eyes without GD (74.2 ± 11.3%). GDs occurred most frequently in the inferotemporal quadrant (46.0%). GDs were significantly more likely to require a re-bubbling when the central parts of the graft were affected (94.0% vs. 35.7%). The number of detachments per graft was directly proportional to the re-bubbling rate. The GDs which required a re-bubbling were on average 56 µm higher and 461 µm wider than the untreated ones. The cornea above the GDs that needed a re-bubbling was significantly thicker than above the untreated GDs (mean 988 ± 102 µm vs. 951 ± 99 µm). CONCLUSIONS: The RGF seems to be a major influencing factor for graft attachment. The most susceptible location of the GD is inferotemporal. The main factors that need to be investigated to decide if a re-bubbling is required are the number of detachments per graft, their dimensions, whether the central portions of the graft are involved, and the corneal thickness above GDs.

PCR testing for herpesviruses in aqueous humor samples from patients with and without clinical corneal endothelial graft rejection.

To compare prevalence of positive PCR tests for herpesviruses between patients with and without a history of clinical corneal endothelial allograft rejection (AGR). Retrospective cross-sectional study with two-group comparison. A total of 307 aqueous humor (AH) samples from 235 Patients and 244 eyes who underwent penetrating keratoplasty or Descemet membrane endothelial keratoplasty or had a diagnostic AH aspiration due to clinical AGR between 2019 and 2023 were tested for DNA of herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV). PCR test results were compared between the two groups (with/without AGR). Another sub-analysis examined the results of patients without a history of herpetic keratitis. A total of 8% of eyes with clinical AGR (9/108) had a positive PCR result for one of the herpesviruses (HSV:3, CMV:3, EBV:2, VZV:1). All patients in the group without AGR had negative PCR results for all previous viruses (0/136). The difference was statistically significant (p < 0.001). The sub-analysis of eyes without a history of herpetic keratitis also revealed significantly more positive herpes PCR results (7/87) in eyes with AGR than in eyes without AGR (0/42, p = 0.005). Clinical AGR after keratoplasty shows a significant correlation to viral replication. Herpetic infection and AGR could occur simultaneously and act synergistically. Timely differentiation between active herpetic infection and/or AGR is pivotal for proper treatment and graft preservation.

Severe ulcerative keratopathy following implantation of an acellular porcine corneal stromal lenticule in a patient with keratoconus.

PURPOSE: To report a case of ulcerative keratopathy following implantation of acellular porcine corneal stroma (APCS) in a patient with keratoconus (KC). METHODS: A 58 year-old patient initially presented with an ulcerative keratopathy in the left eye. Previously, several corneal procedures (including radial keratotomy, laser-in-situ keratomileusis, crosslinking) were performed for KC. Eight months ago, an APCS lenticule (Xenia corneal implant, Gebauer Medizintechnik GmbH, Neuhausen, Germany) was implanted into a stromal pocket because of progressive keratectasia. Visual acuity was hand movement. Anterior segment optical coherence tomography showed a space between the APCS lenticule and the host stroma. Excimer laser-assisted penetrating keratoplasty (PKP, 8.0/8.1 mm) was performed in the left eye. The corneal explant was investigated by light and transmission electron microscopy. RESULTS: Best-corrected visual acuity was 20/40 six weeks after PKP. Light microscopy demonstrated a stromal ulceration down to the APCS lenticule. No stromal cells could be found within the APCS lenticule eight months after implantation. The APCS lenticule did not show a green stain of the collagens with Masson-Goldner staining and exhibited a strong Periodic acid-Schiff positive reaction. Electron microscopy of the APCS lenticule revealed cross-linked collagen lamellae without cellular components. Close to the interface, corneal collagen lamellae of the host cornea were disorganized. Few vital keratocytes were present on the surface of the lenticule and appeared to cause mechanical disruption of the host stroma along the lenticule-stroma interface. CONCLUSION: APCS implantation may lead to severe complications such as ulcerative keratopathy in otherwise uncomplicated KC corneas. In such cases, excimer laser-assisted PKP or Deep Anterior Lamellar Keratoplasty are the methods of choice to restore visual acuity.

Use of In Vivo Corneal Confocal Microscopy to Guide Excimer Laser With Adjunctive Mitomycin C for Treatment of Recalcitrant Acanthamoeba Keratitis.

PURPOSE: The aim of this study was to describe 3 cases of recalcitrant Acanthamoeba keratitis (AK) that were successfully treated using in vivo corneal confocal microscopy (IVCM) to guide excimer laser ablation depth with adjunctive mitomycin C 0.02%. METHODS: Three patients diagnosed with AK did not respond to several weeks of intensive topical therapy with antiamoebic agents. The patient underwent phototherapeutic keratectomy with topical mitomycin C 0.02% application. The maximum stromal depth of cysts measured by IVCM was 80 µm, 100 µm, and 240 µm, and the stromal ablation depths were 80 µm, 100 µm, and 100 µm, respectively. RESULTS: In all 3 eyes, AK resolved after a single excimer laser application, and topical treatment was gradually discontinued within 6 weeks afterward. In 1 eye, penetrating corneal transplantation was performed 6 weeks after phototherapeutic keratectomy because of ongoing severe corneal pain. IVCM and histology of the corneal transplant did not reveal any Acanthamoeba cysts within the excised corneal button. No recurrence was observed during the follow-up period of 19 to 34 months. CONCLUSIONS: IVCM-guided phototherapeutic keratectomy with mitomycin C 0.02% seems to be a safe and successful approach for the treatment of AK, especially in cases of resistance to topical treatment. Corneal IVCM should be performed before laser application to measure cyst depth, determine ablation depth, and assess postoperative treatment success.

Descemet Membrane Endothelial Keratoplasty after failed penetrating keratoplasty- case series and review of the literature.

BACKGROUND: This study aims to evaluate visual outcome, central corneal thickness, and re-bubbling rate in a cohort with undersized sequential Descemet Membrane Endothelial Keratoplasty (DMEK) due to endothelial graft decompensation following primary penetrating keratoplasty (PK). METHODS: All patients who received a sequential DMEK (n = 16) or triple DMEK (n = 2) after failed primary PK between November 2020 and June 2022 were retrospectively evaluated. Analyzed parameters were corrected distance visual acuity (CDVA), central corneal thickness (CCT), re-bubbling rate and graft survival. RESULTS: 18 eyes of 18 patients were included. All patients underwent a DMEK with undersized graft after failed PK(s). Mean time between the last PK and DMEK was 102 ± 82 weeks. Mean follow-up time was 8.9 ± 4.6 months. CDVA increased significantly from 1.12 ± 0.60 logMAR preoperatively to 0.64 ± 0.49 logMAR 6 weeks postoperatively (p = 0.013). Mean CCT decreased significantly from 807 ± 224 µm before to 573 ± 151 µm 6 weeks after DMEK (p = 0.003). Re-bubbling was necessary in eight eyes (44.4%) after a median time of 7 days. The 12-month Kaplan Meier survival was 66.7%. CONCLUSION: In case of endothelial graft decompensation without stromal scars after primary PK, a DMEK can be performed for selected patients who had satisfying CDVA before the endothelial decompensation. Prior to DMEK indication, an AS-OCT should routinely be performed to circularly search for posterior steps at the PK graft margin, as well as shortly after DMEK to exclude a detachment of the endothelial graft. All patients should be informed about a higher re-bubbling rate in comparison to primary DMEK.