Pseudophakic Bullous Keratopathy Research Articles

[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)].

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). 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 6weeks, 6months and 12months and whether these measures depended on the RGH. 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 alarger RGH had no positive influence on endothelial cell loss (r = 0.001; p = 0.974). Our results suggest that alarger graft diameter compared to host corneal size is associated with an increased rate of immune reactions and ahigher re-bubbling rate after DMEK. Otherwise, alarger 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.

Predictive factors for re-bubbling after DMEK: focus on the posterior corneal surface.

To understand whether the preoperative morphology of the posterior corneal surface influences the rate of re-bubbling after Descemet membrane endothelial keratoplasty (DMEK). After retrospectively analyzing the medical records of patients undergoing DMEK, in this multicentric cross-sectional study, we performed a binomial logistic regression analysis to assess significant predictors of re-bubbling and re-transplantation after surgery. Analyzed parameters included the preoperative diagnosis, anterior and posterior surface K1/K2, central corneal thickness, posterior Q value, and other posterior corneal surface parameters evaluated on the elevation maps produced by anterior segment optical coherence tomography. Results were stratified based on the surgeons' experience. We included 202 eyes of 202 patients with a mean age of 69.5 ± 12.4years; 154 eyes were operated by a high-volume surgeon and 48 by one with less experience; 48 eyes (23.8%) underwent [Formula: see text] 1 re-bubbling and 14(6.9%) [Formula: see text] 1 re-transplantation. The presence of positive/less-negative posterior corneal irregularities and irregularities with greater absolute height had a significantly higher risk of re-bubbling in both the expert and less expert group (OR = 2.85 and 1.42, OR = 3.22 and 3.01, respectively, p < 0.05), whereas more negative posterior K1 and K2 were significant risk factors only in the former group (OR = 0.67 and 0.55, respectively, p < 0.05). Endothelial decompensation other than Fuchs and pseudophakic bullous keratopathy, more negative posterior Q values and smaller distances between center, and the highest/lowest posterior corneal surface irregularity correlated with an increased risk of graft failure (OR 1.23, 1.21, and 1.29, respectively, p < 0.05). Posterior corneal surface morphology significantly influences the risk of re-bubbling after DMEK.

Artificial Endothelial Layer Implantation After Multiple Failed Keratoplasties.

Presenting the first case of noncellular corneal endothelial substitute after multiple failed penetrating keratoplasty and lamellar endothelial keratoplasty. Our case presented with pseudophakic bullous keratopathy after a history of 2 rejected PKs and 1 rejected Descemet stripping automated endothelial keratoplasty. We implanted an artificial endothelial layer. The implant remained fully attached for a follow-up period of 12 months, and central corneal thickness decreased significantly. The patient reported improvement in her subjective vision, although ocular comorbidities limited the visual potential. This new device could serve as an alternative to lamellar endothelial corneal transplantation in cases where tissue rejection has occurred and is highly likely to recur. The technique is simple, and the deswelling effect on the cornea persisted, although the visual results require further validation in patients with a higher visual potential.

Short-term Visual Outcome Following Anterior Chamber Intraocular Lens Implantation—The Experience of a Rural Teaching Hospital

Purpose: To report the indications, frequency and short-term visual outcome of anterior chamber intraocular lens implantation (ACIOL) in a rural tertiary hospital; as well as to describe the reasons for poor visual outcome following ACIOL implantation. Methods: This was a retrospective descriptive study of all patients aged at least 18 years who underwent cataract extraction and implantation of ACIOL between January 2004 and May 2023. Information retrieved from the case records included preoperative visual acuity, indication for ACIOL implantation, first-day postoperative visual acuity, and 6 weeks postoperative visual acuity. Results: A total of 133 eyes of 126 patients were reviewed in this study. The mean age was 60.9 years, with a male-to-female ratio of 1.7:1. The most common indication for ACIOL use was a posterior capsular rent (70.7%). The first-day postoperative visual acuity was 6/18 or better in 7 (5.3%) patients, and by the sixth postoperative week, this proportion had increased to 28.6% (38 patients). The most common complication on the first day post-op was striate keratopathy (72.9%), while the most common at 6 weeks was pseudophakic bullous keratopathy (21.1%). Conclusion: Although complications were noted with the use of ACIOLs, improvement in visual acuity was observed at 6 weeks. ACIOLs may still be relevant in settings where automated vitrectomy equipment is not readily available, but the availability of expertize is required for its implantation and the complication profile of ACIOLs must always be taken into consideration.

The Role of Rho Kinase Inhibitors in Corneal Diseases.

The cornea, as the outermost layer of the eye, plays a crucial role in vision by focusing light onto the retina. Various diseases and injuries can compromise its clarity, leading to impaired vision. This review aims to provide a thorough overview of the pharmacological properties, therapeutic potential and associated risks of Rho-associated protein kinase (ROCK) inhibitors in the management of corneal diseases. The article focuses on four key ROCK inhibitors: Y-27632, fasudil, ripasudil, and netarsudil, providing a comparative examination. Studies supporting the use of ROCK inhibitors highlight their efficacy across diverse corneal conditions. In Fuchs' endothelial corneal dystrophy, studies on the application of Y-27632, ripasudil, and netarsudil demonstrated noteworthy enhancements in corneal clarity, endothelial cell density, and visual acuity. In pseudophakic bullous keratopathy, the injection of Y-27632 together with cultured corneal endothelial cells into the anterior chamber lead to enhanced corneal endothelial cell density and improved visual acuity. Animal models simulating chemical injury to the cornea showed a reduction of neovascularization and epithelial defects after application of fasudil and in a case of iridocorneal endothelial syndrome netarsudil improved corneal edema. Addressing safety considerations, netarsudil and ripasudil, both clinically approved, exhibit adverse events such as conjunctival hyperemia, conjunctival hemorrhage, cornea verticillata, conjunctivitis, and blepharitis. Monitoring patients during treatment becomes crucial to balancing the potential therapeutic benefits with these associated risks. In conclusion, ROCK inhibitors, particularly netarsudil and ripasudil, offer promise in managing corneal diseases. The comparative analysis of their pharmacological properties and studies supporting their efficacy underscore their potential therapeutic significance. However, ongoing research is paramount to comprehensively understand their safety profiles and long-term outcomes in diverse corneal conditions, guiding their optimal application in clinical practice.

Trends in keratoplasty from central and Northern India. Part I: Indications for keratoplasty.

To report the indications for keratoplasty and analyze trends in two decades in India. This was a retrospective review of eye bank registries of six tertiary eye care centers located in central and northern India from 2005 to 2021. The patterns of corneal pathology and changes in trends were analyzed. Between 2005 and 2021, 13223 corneal grafts were performed in the six collaborating tertiary eye care centers. The most common indication for keratoplasty in both decades was corneal ulcer (41.1%), followed by corneal scar (25.5%), failed graft (12.0%), post-cataract surgery corneal edema (11.7%), corneal dystrophies (3.1%), corneal ectasia (1.8%), corneal trauma (0.3%), congenital corneal opacity (0.3%), and others (4.1%). An increasing trend was seen in corneal ulcers, failed grafts, and keratoconus. A reducing trend was seen in corneal scar and aphakic bullous keratopathy. There was no change in pseudophakic bullous keratopathy and Fuchs endothelial corneal dystrophy. Corneal ulcers, corneal scars, failed grafts, and post-cataract surgery corneal edema remained the foremost indications for keratoplasty in two decades in India. An increasing trend was seen in corneal ulcers and failed grafts which are of concern as these indications carry a poorer outcome. Capacity building in lamellar keratoplasty techniques is the need of the hour as pseudophakic bullous keratopathy was an important indication, and an increasing trend was noticed in keratoconus.

Five-year clinical outcomes of 107 consecutive DMEK surgeries.

The long-term clinical outcomes, postoperative complications, and graft survival of Descemet-membrane endothelial keratoplasty (DMEK) remain poorly understood. We retrospectively assessed these variables in all consecutive eyes that underwent DMEK for any indication in 2014-2018. The findings were compared to the long-term DMEK studies of five other groups (3-10-year follow-up). Patients underwent ophthalmological tests preoperatively, at 1, 3, 6, and 12 postoperative months, and then annually. Five-year graft survival was determined by Kaplan-Meier estimator. Change in best-corrected visual acuity (BCVA), endothelial-cell density (ECD), and central-corneal thickness (CCT) at each timepoint was determined. 107 eyes (80 patients; 72 years old; 67% female) underwent first-time DMEK for uncomplicated Fuchs endothelial corneal dystrophy (94% of eyes), pseudophakic bullous keratopathy (3%), and regraft after previous keratoplasty (3%). The most common complication was graft detachment requiring rebubbling (18%). Thirteen grafts (12%) failed at ≤15 months. Cumulative 5-year graft-survival probability was 88% (95% confidence intervals = 79-94%). BCVA improved from 0.6 logMAR preoperatively to 0.05 logMAR at 1 year (p<0.0001) and then remained stable. Donor ECD dropped by 47% at 6 postoperative months and then continued to decrease by 4.0%/year. Five-year endothelial-cell loss was 65% (from 2550 to 900 cells/mm2). CCT dropped from 618 to 551 μm at 5 years (p<0.0001). These findings are generally consistent with previous long-term DMEK studies. DMEK has low complication and high graft-survival rates and excellent clinical outcomes that persist up to 5 years post-surgery. DMEK seems to be a safe and effective treatment in the long term.

Netarsudil-Associated Reticular Epithelial Edema Directly Influenced by Endothelial Dysfunction in a Post-Endothelial Keratoplasty Patient

Purpose: The purpose of this report was to describe a case in which reticular epithelial edema secondary to topical netarsudil ophthalmic solution 0.2% occurred directly in relation to focal endothelial dysfunction in a post-endothelial keratoplasty eye. Methods: This was a case report. Results: A 76-year-old man with a complex ocular history was diagnosed with pseudophakic bullous keratopathy of the left eye. Topical netarsudil was prescribed to treat his glaucoma and to attempt improvement of his corneal edema. The corneal examination remained stable for many months, but the patient eventually underwent a Descemet stripping automated endothelial keratoplasty (DSAEK) for worsening corneal edema. One week later, the patient was observed to have 360-degree reticular epithelial edema around the periphery of the DSAEK graft. Given the lack of visual significance and need for continued glaucoma treatment, the patient was continued on netarsudil. The reticular epithelial edema later became restricted to areas outside the graft zone as the peripheral DSAEK graft endothelial cell function improved. Two months post-DSAEK, the patient developed a partial inferior endothelial graft rejection related to inadvertent cessation of topical steroid, with keratic precipitates, stromal edema, and new overlying reticular epithelial edema. On treatment and resolution of the DSAEK graft rejection, the overlying reticular epithelial edema also resolved. Conclusions: This case clearly demonstrates that netarsudil-associated reticular epithelial edema is highly likely to be related to endothelial cell dysfunction and that if endothelial cell dysfunction improves, the reticular epithelial edema will also improve, despite the continuation of netarsudil.

Mediators of Visual Acuity in Descemet Membrane Endothelial Keratoplasty and Ultrathin Descemet Stripping Automated Endothelial Keratoplasty.

The aim of this study was to investigate mediators of visual acuity in ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) compared with Descemet membrane endothelial keratoplasty (DMEK). This was a prespecified secondary analysis of the Descemet Endothelial Thickness Comparison Trial, a prospective, randomized controlled trial comparing UT-DSAEK with DMEK. Subjects with Fuchs endothelial dystrophy or pseudophakic bullous keratopathy presenting to 2 academic centers were enrolled and randomized to either UT-DSAEK (n = 25 eyes) or DMEK (n = 25 eyes). Higher order aberrations (HOAs) and corneal densitometry were measured with Pentacam Scheimpflug imaging at 3, 6, 12, and 24 months. The posterior corneal surface at the 6.0-mm optical zone had significantly less total HOAs (P <0.001) in the DMEK group compared with UT-DSAEK at 24 months. Anterior and posterior corneal densitometry improved from baseline to 24 months for both UT-DSAEK and DMEK, but there was no significant difference between the 2 groups. Corneal densitometry and posterior HOAs were both associated with best-corrected visual acuity (P <0.05). DMEK had 1.3 logarithm of the minimum angle of resolution better visual acuity compared with UT-DSAEK at 24 months. Approximately 64% of this effect was mediated through posterior HOAs, whereas none was mediated through anterior HOAs or densitometry. Decreased posterior HOAs mediate better visual acuity and account for improved vision after DMEK compared with UT-DSAEK. Corneal light scatter as measured by densitometry is similar between UT-DSAEK and DMEK, indicating that the increased thickness and stromal-stromal interface in UT-DSAEK do not significantly affect visual acuity.

Headache associated with travoprost

Background: Putative adverse effects of prostaglandin analogs in patients treated for glaucoma include periocular skin darkening, herpes simplex keratitis, cystoid macular edema, iritis, and headaches. Here, we report a case of migraine headache after a travoprost administration and discuss the role of prostaglandin analogs in migraine-like headaches.&#x0D; Case Presentation: A 70-year-old man visited the hospital complaining of pain, redness, and sensitivity to light for 1 week associated with gradual loss of vision in the right eye after cataract surgery, which had been performed 2 years prior. After the examination, the patient was diagnosed with pseudophakic bullous keratopathy and advised to undergo optical penetrating keratoplasty of the right eye. On postoperative day 3, his intraocular pressure (IOP) was 30 mmHg at 10:00 AM in the right eye. A single dose of 0.004% travoprost was instilled in the right eye on the same day. His IOP decreased to 16 mmHg at 2:00 PM. The next day, he presented with migraine-like headache that had started within 1 h after the instillation the previous night. Unremarkable neurological examination and neuroimaging suggested that travoprost had caused the migraine. Although the headache gradually resolved, it reappeared after the administration of other prostaglandins. Trabeculectomy was performed on the right side. The IOP was controlled, and the headache was resolved.&#x0D; Conclusions: This case indicates a potential causal relationship between topical prostaglandin analogs and migraine-like headaches, as evidenced by symptom resolution upon discontinuation. However, large-scale studies including control groups are required to prove a causal relationship between topical prostaglandin analog administrations and headache development.

A Comprehensive Investigation Into the Outcomes of Descemet's Stripping Endothelial Keratoplasty (DSEK) as a Treatment for Corneal Endothelial Disorders.

Descemet's stripping endothelial keratoplasty (DSEK) has emerged as the preferred method for posterior lamellar keratoplasty, as it enables the replacement of the compromised host endothelium with a viable donor lamella. The objective of this study was to assess the impact of DSEK on surgical outcomes and visual acuity. The research was carried out from November 2019 to October 2021, encompassing a sample of 18 patients (18 eyes) who satisfied the inclusion criteria for DSEK. The pre-operative evaluation was performed once before the surgery, while post-operative evaluations were conducted at one, three, and six months after the surgical intervention. The main variables assessed in this study encompassed demographic characteristics, visual acuity, surgical techniques, and surgical complications employed during the surgical procedure. The collected data were statistically analyzed using IBM SPSS software version 21 (IBM Corp., Armonk, NY, USA). Patients in the study ranged in age from 25 to 70, with a mean age of 53.16 ± 14.19 years. The participants were 61% male and 39% female. The main reasons for DSEK use were pseudophakic bullous keratopathy (61%) and post-penetrating keratoplasty (PK) graft failure (17%). The other indications were aphakic bullous keratopathy (11%), bullous keratopathy with cataracts (5%), and Fuchs's endothelial dystrophy (5%). The study included 18 eyes: 14 eyes underwent DSEK, two underwent DSEK with small-incision cataract surgery (SICS) and posterior chamber intraocular lens (PCIOL) implantation, and two underwent DSEK with scleral-fixated FIL. A significant improvement in best-corrected visual acuity (BCVA) was observed at six-month follow-up (0.73 ± 0.37 vs. 1.73 ± 0.59 logMAR pre-operatively). During donor cornea dissection, buttonholing was the main concern, occurring 11% of the time. Descemet's perforation and donor preparation thickness variations were also observed. Reverse donor unfolding, incomplete DM stripping, and donor button displacement were quickly addressed and managed. Post-operative graft failure occurred in 22% of cases, while acute graft rejection occurred in 11%. Graft dislocation, pupillary block, and secondary glaucoma each had a 5% prevalence. Descemet's stripping endothelial keratoplasty is a safe and effective treatment for corneal endothelial disorders, particularly in cases where scarring is not present. Surgical skills are essential to achieving the desired results. Descemet's stripping endothelial keratoplasty is favored over conventional keratoplasty for endothelial dysfunction due to its technical advantages and manageable risks. Our research demonstrates a significant improvement in visual acuity through DSEK. Despite manageable post-operative complications, it is vital to educate patients and medical professionals on surgical complexities. Descemet's stripping endothelial keratoplasty appears promising for the treatment of endothelial disorders, but its long-term implications must be studied.

Nanotopography by chromatic confocal microscopy of the endothelium in Fuchs endothelial corneal dystrophy, pseudophakic bullous keratopathy and healthy corneas

AimTo investigate the interest of chromatic confocal microscopy (CCM) to characterise guttae in Fuchs endothelial corneal dystrophy (FECD).MethodsDescemet’s membranes (DM) were obtained during endothelial keratoplasty in patients with FECD and...

Optical quality of the cornea after Descemet membrane endothelial keratoplasty surgery: early results from Türkiye.

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. 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). 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<0.05). The corneal densitometry values at postoperative month 6 were elevated in all layers and zones relative to the healthy group (P<0.05). The root mean square of higher-order aberrations in postoperative period was elevated significantly (P<0.001). Six months after operation, the optical quality of the cornea following DMEK surgery did not achieve the level of a healthy cornea.

Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty Using a Preloaded Imported Graft.

Although the popularity of Descemet membrane endothelial keratoplasty (DMEK) is increased, there is still few clinical studies in Korea. In this study, we aimed to report the initial clinical outcomes of DMEK in patients followed up for more than 6 months. A total of 96 eyes that underwent DMEK by a single surgeon for Fuchs endothelial corneal dystrophy, pseudophakic bullous keratopathy, or other indications were evaluated for best-corrected visual acuity (BCVA), endothelial cell density (ECD), central corneal thickness (CCT), postoperative complications, and graft survival. The postoperative BCVA significantly increased compared to the preoperative BCVA by 59.4% (1.00 ± 0.77 logarithm of the minimum angle of resolution vs. 0.67 ± 0.76 logarithm of the minimum angle of resolution, p &lt; 0.001). The average preoperative ECD was 754 ± 382 cells/mm2, increasing to 1,333 ± 562 cells/mm2 at 3 months (76.8%, p &lt; 0.001), 1,334 ± 632 cells/mm2 at 6 months (76.9%, p &lt; 0.001), 1,121 ± 474 cells/mm2 at 12 months (48.7%, p = 0.024), and 972 ± 458 cells/mm2 at 24 months postoperatively (28.9%, p = 0.445). Compared to 3 months, the ECD declined by 15.9% at 12 months (p = 0.009) and 27.1% at 24 months postoperatively (p = 0.158). The average CCT was 675 ± 113 μm preoperatively, decreasing to 581 ± 102, 574 ± 101, and 594 ± 94 μm at 6, 12, and 24 months after DMEK, respectively (p &lt; 0.001 between all follow-up time points). Allograft rejection was detected in three (3.1%) and 14 eyes (14.6%) underwent retransplantation at an average of 10.1 ± 8.4 months after DMEK. DMEK is promising for maintaining corneal clarity, low postoperative complication rates, and stable graft longevity.

Histopathology of the Host Cornea Following Penetrating Keratoplasty.

To study the ultra-structural changes in the diseased corneal cells by histopathology, electron microscopy, and immunohistochemistry using conventional antisera and monoclonal antibodies with the ultimate goal of justifying pre-treatment and post-treatment advice and, if necessary, modifying the post-operative treatment for improved graft survival. Thirty cases registered for penetrating keratoplasty were worked up for routine systemic and ophthalmic criteria. A full-thickness diseased cornea was subjected to histopathology after suitable staining and fixation, including electron microscopic and immunohistochemical studies where possible. The ages ranged from four to 60 years. The majority (26%) were in the age group of 31-40 years. The most frequent causes of corneal pathology that underwent keratoplasty include post-traumatic corneal scarring (40%), followed by pseudophakic bullous keratopathy (16.7%). In almost all cases, the histopathology confirmed the existing clinical diagnosis. Histopathology helped to confirm one doubtful case of Fuchs' dystrophy and to contradict one clinical diagnosis of pseudophakic bullous keratopathy, which turned out to be epithelization of the anterior chamber. The results underline the significance of the histopathological study of these corneal conditions to increase the post-surgical survival of the corneal graft.

Etiology and outcome of penetrating keratoplasty in bullous keratopathy post-cataract surgery vs post-glaucoma surgery.

To investigate the causes of bullous keratopathy (BK) in the Korean population and analyze the results of penetrating keratoplasty (PK) in BK eyes associated with the top two causes: pseudophakic bullous keratopathy (PBK) and glaucoma surgery-associated BK (GBK). Medical records were reviewed of patients diagnosed with BK at a tertiary referral center between 2010 and 2020. The predisposing conditions, clinical characteristics and therapeutic outcomes after PK were analyzed and compared. Of total 340 BK eyes, 70% (238 eyes) were associated with ocular surgery; most commonly, cataract surgery (48%, 162 eyes) and glaucoma surgery/laser (21%, 70 eyes). The BK onset was faster following glaucoma surgery/laser (91.7 ± 94.4 months) than following cataract surgery (160.7 ± 138.0 months, p < 0.001). The median survival time of allografts was shorter in GBK than in PBK (24.0 vs 51.0 months, p = 0.020). Best-corrected logMAR visual acuities were lower in GBK than in PBK after PK (1.4 ± 0.7 vs 0.9 ± 0.6, p = 0.017 at one year; 1.8 ± 0.7 vs 1.1 ± 0.8, p = 0.043 at three years). Intraocular surgery is the major predisposing condition of BK in Korea. GBK developed earlier and its therapeutic outcome was poorer, compared to PBK.

The Cornea: No Difference in the Wound Healing Response to Injury Related to Whether, or Not, There's a Bowman's Layer.

Bowman's layer is an acellular layer in the anterior stroma found in the corneas of humans, most other primates, chickens, and some other species. Many other species, however, including the rabbit, dog, wolf, cat, tiger, and lion, do not have a Bowman's layer. Millions of humans who have had photorefractive keratectomy over the past thirty plus years have had Bowman's layer removed by excimer laser ablation over their central cornea without apparent sequelae. A prior study showed that Bowman's layer does not contribute significantly to mechanical stability within the cornea. Bowman's layer does not have a barrier function, as many cytokines and growth factors, as well as other molecules, such as EBM component perlecan, pass bidirectionally through Bowman's layer in normal corneal functions, and during the response to epithelial scrape injury. We hypothesized that Bowman's layer represents a visible indicator of ongoing cytokine and growth factor-mediated interactions that occur between corneal epithelial cells (and corneal endothelial cells) and stromal keratocytes that maintain the normal corneal tissue organization via negative chemotactic and apoptotic effects of modulators produced by the epithelium on stromal keratocytes. Interleukin-1 alpha, produced constitutively by corneal epithelial cells and endothelial cells, is thought to be one of these cytokines. Bowman's layer is destroyed in corneas with advanced Fuchs' dystrophy or pseudophakic bullous keratopathy when the epithelium becomes edematous and dysfunctional, and fibrovascular tissue commonly develops beneath and/or within the epithelium in these corneas. Bowman's-like layers have been noted to develop surrounding epithelial plugs within the stromal incisions years after radial keratotomy. Although there are species-related differences in corneal wound healing, and even between strains within a species, these differences are not related to the presence or absence of Bowman's layer.

Topical Ripasudil for the Treatment of Segmental Corneal Edema: A Case Series.

Ripasudil, a rho-kinase inhibitor, has gained popularity as an adjunctive therapy after Descemet stripping only to hasten visual recovery. Ripasudil has been shown to increase corneal endothelial cell proliferation and intercellular adhesion, and decrease endothelial cell apoptosis. We present 4 cases in which persistent corneal edema after various anterior segment surgeries was successfully treated with topical ripasudil, and 1 case in which corneal edema did not improve with use of ripasudil. Retrospective chart review revealed 5 patients treated with topical ripasudil for persistent corneal edema that failed to improve with conventional, nonsurgical treatments. In each case, the patient had symptomatic, persistent, focal corneal edema which followed a surgical procedure in the anterior segment. The various etiologies of corneal edema included graft failure after Descemet stripping endothelial keratoplasty, a failed penetrating keratoplasty, and 3 cases of pseudophakic corneal edema. These patients experienced improved vision and partial or complete resolution of corneal edema after 2 to 4 weeks of topical ripasudil administered 4 times daily. One patient with pseudophakic bullous keratopathy had edema that initially improved on topical ripasudil, but after cessation of the medication, developed progressive corneal edema and required endothelial keratoplasty. In patients with focal corneal edema resulting from surgical trauma to the endothelium who failed to clear over time with conservative measures, topical ripasudil was shown to be an effective treatment option that in most cases improved vision and helped reduce the need for endothelial transplantation.

Role of Direct Supervision in the Learning Curve of Descemet Membrane Endothelial Keratoplasty Surgery.

The aim of this study was to compare complication rates of Descemet membrane endothelial keratoplasty (DMEK) performed by directly supervised and nondirectly supervised corneal fellows. This study was a retrospective, comparative case series of DMEK surgeries performed by novice surgeons (less than 15 DMEK cases) with or without direct direct expert supervision. Patients who underwent surgery for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy with a minimum follow-up of 12 weeks were included. Data on patients' demographics, surgical details, surgeon level, intraoperative and postoperative complications, and rate of rebubbling were collected. In this study, 41 nondirectly supervised and 48 directly supervised DMEK surgeries were included. At 6 months, 67.4% of eyes achieved a best-corrected visual acuity of ≤0.3 logMAR with no significant difference between groups ( P = 0.95). Intraoperative complications occurred in 22% of cases in the nondirect supervision group and 4.2% in the direct supervision group ( P = 0.02). Postoperative complications occurred in 9.8% of cases in the nondirect supervision group and 6.2% of cases in the direct supervision group ( P = 0.7). The rebubbling rate was comparable in the 2 groups (34.1% vs. 33.3%, P = 1.0). Five cases (12.2%), all from the nondirect supervision group, required secondary keratoplasty ( P = 0.02). The overall complication rate was significantly higher in the nondirect supervision group (31.7% vs. 10.4%, P = 0.03). Functional success can be achieved in directly supervised or nondirectly supervised DMEK surgery. However, nondirectly supervised DMEK surgery may associate with higher rates of complications.

Corneal Guttae After Descemet Membrane Endothelial Keratoplasty.

The aim of this study was to report on the occurrence of corneal guttae after Descemet membrane endothelial keratoplasty (DMEK). In this retrospective case series, 13 eyes of 13 patients who underwent DMEK at 2 tertiary referral centers between 2007 and 2021 (average available follow-up 73 ± 52 months, range 18-174 months) and showed corneal guttae during postoperative examinations were included. Eye bank images were retrospectively reviewed. Occurrence of guttae was observed by specular microscopy in 13 eyes. In 11 cases, presence of guttae was confirmed by confocal microscopy and in 1 case by histology. Five eyes showed an increase in guttae density during the postoperative course. Surgery indications were Fuchs endothelial corneal dystrophy (n = 11), pseudophakic bullous keratopathy (n = 1), and DMEK graft failure after allograft rejection (n = 1); the latter eye had shown no signs of guttae after primary DMEK. Two eyes with guttae required a repeat DMEK due to graft failure. At the last available follow-up, all 11 remaining eyes had clear corneas and 10 eyes had a best-corrected visual acuity of ≥0.9 (decimal). During donor cornea processing in the eye bank, no guttae were observed on the donor tissue. Corneal guttae can occur after DMEK including in eyes operated for indications other than Fuchs endothelial corneal dystrophy and most likely guttae were present on the donor graft but were not detectable by routine slit-lamp and light microscopy evaluation in the eye bank. Postoperative guttae density varies among patients and especially small isolated guttae do not seem to affect clinical outcomes.