The treatment of end-stage corneal disease: penetrating keratoplasty compared with Boston type 1 keratoprosthesis.

Penetrating keratoplasty (PKP) yields excellent results for restoring vision in end-stage corneal diseases. However, its success is limited to high-risk diseases such as aniridia, chemical burns, autoimmune corneal diseases, and herpetic eye disease. Boston type 1 keratoprosthesis (BKPro) offers another option to these patients. Since 1992, improvements in perioperative management and device construction have significantly increased the use of BKPro worldwide and challenged the therapeutic role of PKP in these patients. This review aims to evaluate BKPro's place in the treatment algorithm of these high-risk patients to assist surgeons' decision-making. PKP and BKPro are compared in three outcome categories: visual acuity, graft retention and failure, and complications profile. Special attention is given to comparing secondary BKPro versus repeated PKP as well as primary BKPro versus primary PKP. We conclude that secondary BKPro bears a better prognosis than repeated PKP in most high-risk patients. Similarly, primary BKPro likely confers improved outcomes over primary PKP in most high-risk recipients. However, current evidence is based on retrospective designs, and controlled prospective randomized trials are required to validate these conclusions.

Nonosseous Periocular Manifestations of Langerhans Cell Histiocytosis: A Case Report and Systematic Review.

PURPOSE: Langerhans cell histiocytosis (LCH) is a disorder of dendritic cell proliferation that typically involves bone. It can be diagnostically challenging when LCH presents without bony involvement, leading to delays in diagnosis and treatment. In this study, the periocular manifestations of LCH in cases where the underlying orbital bones are not involved are described through a systematic review. METHODS: A systematic review of the literature was performed to capture all cases of LCH that involved the periocular region but not the underlying orbital bones. These included LCH cases that involved the periocular skin, the ocular surface, and the orbital tissue. The authors also highlight an additional case where LCH presented with periocular edema and multifocal, nodular conjunctival lesions. RESULT: This review illustrates that LCH rarely presents with periocular infiltration without orbital bone involvement. In these atypical cases, LCH can present as an eyelid mass, a chalazion-like lesion, generalized periocular swelling, ocular surface lesions, or infiltration of any orbital structure. Ocular surface LCH has a higher rate of recurrence than other periocular LCH. Orbital LCH can involve any tissue including extraocular muscles, the lacrimal gland, or indistinct areas within the orbit. CONCLUSIONS: LCH is a clinicopathologic diagnosis. Although most cases involve the bone, any soft tissue can be involved. Biopsy is required to confirm the diagnosis of this heterogeneous disease.

Update on Bowman layer transplantation.

PURPOSE OF REVIEW: Bowman layer transplantation is a novel technique that may stabilize progressive ectatic corneal changes in eyes with keratoconus, which are too steep or too thin for ultraviolet corneal crosslinking or intracorneal ring segments. In this way, patients can maintain stable vision with contact lenses, and avoid or postpone more invasive corneal transplants, such as penetrating keratoplasty or deep anterior lamellar keratoplasty. This review aims to summarize the currently available literature on Bowman layer transplantation. RECENT FINDINGS: Bowman layer transplantation seems to be a promising, minimally invasive procedure for managing advanced keratoconus with a reported 5-year success rate of 84%. The procedure allows patients to maintain acceptable visual acuity with glasses or contact lens correction. Although graft preparation and surgical technique can be challenging, adaptation of technologies, such as femtosecond laser and intraoperative anterior segment optical coherence tomography, may help overcome these barriers to enable Bowman layer transplantation to become a more widely adopted procedure. SUMMARY: Bowman layer transplantation may offer an alternative, less invasive treatment option for eyes with advanced, progressive keratoconus.

Descemet membrane endothelial keratoplasty and refractive surgery.

PURPOSE OF REVIEW: Descemet membrane endothelial keratoplasty (DMEK) has become a first-line treatment in corneal endothelial diseases because of its exceptional clinical outcomes and low complication rates. Because of its improved refractive predictability, DMEK is now also considered for managing cases with endothelial decompensation following previous refractive procedures, or in combination with those. This article reviews the clinical outcomes in these cases and discusses the possibility of refractive interventions following DMEK. RECENT FINDINGS: DMEK has been successfully performed in eyes after laser in-situ keratomileusis, eyes after anterior chamber intraocular lens (IOL) implantation and aphakic eyes. Often, DMEK is combined with cataract surgery (triple-DMEK). Initial reports on reducing the refractive cylinder by toric IOL implantation are available. Although there are some reports on phacoemulsification and IOL implantation after phakic DMEK, reports on laser refractive procedures following DMEK are lacking. SUMMARY: In contrast to earlier keratoplasty techniques, DMEK induces on average only mild refractive shifts owing to the 'natural' restoration of the cornea. As such, DMEK may be ideal in managing corneal decompensation in refractive patients. However, further studies are required to assess the safety and efficacy of DMEK after refractive treatment and of refractive procedures following DMEK.

Comparison of Endophthalmitis Rates after Alcohol-Based Chlorhexidine and Povidone-Iodine Antisepsis for Intravitreal Injections.

OBJECTIVE: Intravitreal injections (IVIs) are the most frequently performed intraocular procedure in Canada. Povidone-iodine (PI) is the current gold standard for antisepsis for IVI and is widely used; chlorhexidine (CH) is a possible alternative antiseptic agent. This study aims to compare rates of endophthalmitis after IVI with 0.05% chlorhexidine with a 4% alcohol base antisepsis to rates of endophthalmitis after IVI with 10% PI antisepsis. DESIGN: Retrospective cohort study. SUBJECTS: Eyes that received IVI between May 2019 and October 2022 at a group retina practice in Edmonton, Canada. METHODS: Eyes at a single center received focal conjunctival application of either 10% PI antisepsis or 0.05% CH in 4% alcohol antisepsis for 30 seconds before each IVI. MAIN OUTCOME MEASURE: Rates of endophthalmitis between the PI and CH groups. RESULTS: A total of 170 952 IVIs were performed during the study period. A total of 31 135 were performed using CH prophylaxis compared with 139 817 with PI prophylaxis. Among all IVIs there were 49 total cases of endophthalmitis, 29 in the PI group (0.021%) and 20 in the CH group (0.064%). There was a statistically significant difference in the rates of endophthalmitis between the 2 groups (P < 0.001). The odds ratio for developing endophthalmitis with CH antisepsis was 3.1 (95% confidence interval, 1.9-5.2) compared with PI antisepsis. There were increased odds of developing endophthalmitis with aflibercept injection compared with bevacizumab (odds ratio, 3.48; 95% confidence interval, 2.09-7.24). CONCLUSIONS: There is a statistically significant difference in rates of endophthalmitis between alcohol-based CH and PI antisepsis for IVI in our patient population utilizing the methods discussed. In our center, alcohol-based CH is now considered a second-line antiseptic agent. Further studies are warranted to further assess the endophthalmitis rate utilizing these 2 antiseptic agents. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Cost-effectiveness of locally prepared Descemet membrane endothelial keratoplasty grafts in Edmonton.

OBJECTIVE: This study aimed to show the cost-effective benefits of creating a sustainable local program where Descemet membrane endothelial keratoplasty (DMEK) grafts were prepared locally instead of imported from American eye banks. DESIGN: Retrospective observational study. METHODS: In 2018, 2 local technicians were trained to prestrip DMEK grafts in Edmonton up to 2 days before surgery when local donor tissue was available. When no local tissue was available, prestripped DMEK grafts were imported from U.S. eye banks. The total cost of locally prepared and imported DMEK grafts over 27 months was compared with the cost that otherwise would have been accrued if all DMEK grafts had been imported. RESULTS: Over 27 months, 82 DMEK grafts (55.3%) were prepared locally and 63 DMEK grafts (44.7%) were imported. The total cost of preparing 82 grafts locally was $9349.19. The total cost of importing 63 prestripped DMEK grafts was $282 431.52. The combined total cost of locally prepared and imported DMEK grafts was $291 780.71. The total cost that otherwise would have been incurred if every graft was imported was $632 108.64. This difference in costs was $340 327.93 over 27 months. CONCLUSIONS: Establishing a sustainable program to make high-quality DMEK grafts with local donor corneas is a cost-effective alternative to importing prestripped DMEK grafts in Edmonton.

Clinical outcomes of Descemet membrane endothelial keratoplasty performed in eyes with keratoconus and corneal endothelial dysfunction.

PURPOSE: To evaluate the clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) performed in eyes with comorbid keratoconus (KCN) and corneal endothelial dysfunction. METHODS: Twenty-five consecutive eyes of 14 patients with comorbid stable KCN underwent DMEK for corneal endothelial dysfunction; best spectacle corrected visual acuity (BSCVA), maximum corneal curvature (Kmax), maximum corneal power (Pmax), central corneal thickness (CCT), and intra- and postoperative complications were assessed. RESULTS: Excluding eyes requiring re-transplantation for primary graft failure (n = 3), all eyes showed improvement in BSCVA, reaching ≥ 20/40 (0.5) in 86%, ≥ 20/25 (0.8) in 55%, and ≥ 20/20 (1.0) in 27% by one month postoperatively; 90%, 76%, and 48% by 6 months postoperatively; and 88%, 76%, and 47% by 12 months postoperatively. CCT decreased from 571µm preoperatively to 485µm at 1 month (p < 0.001) and 481µm at 12 months (p < 0.001). Kmax decreased by a median of 1.4 diopters (D) at 1 month (p = 0.003) and 3.1 D at 12 months (p = 0.021), and every eye with a preoperative Kmax ≥ 46 D demonstrated flattening. Pmax decreased by 2.1 D at 1 month (p = 0.001) and 4.0 D at 12 months (p = 0.016). CONCLUSION: DMEK is technically feasible in eyes with comorbid KCN and may give excellent outcomes visual and refractive outcomes, including significant corneal flattening, which may potentially create a visually significant hyperopic shift in patients with severely ectatic corneas.

Survivability of locally prepared versus imported Descemet membrane endothelial keratoplasty grafts in Edmonton.

OBJECTIVE: This study aimed to evaluate the long-term graft survivability of locally prestripped versus imported prestripped Descemet membrane endothelial keratoplasty (DMEK) grafts in Edmonton. DESIGN: Prospective cohort study of patients who underwent DMEK surgery between January 1, 2020, and December 31, 2020. PARTICIPANTS: All patients receiving a DMEK transplant during the study period in Edmonton. METHODS: Two local technicians were trained to prestrip DMEK grafts in Edmonton. When available, local tissue was prestripped for DMEK surgery; otherwise, prestripped DMEK grafts were imported from an accredited American eye bank. Patient characteristics and DMEK graft characteristics and DMEK survivability were evaluated and compared between the 2 groups. RESULTS: Thirty-two locally prestripped DMEK grafts and 35 imported prestripped DMEK grafts were used during the study period. Donor cornea characteristics and patient characteristics were similar between the 2 groups. Best-corrected visual acuity improved up to 6 months postoperatively and was 0.2 logMAR in the locally prestripped DMEK group and 0.2 logMAR in the imported DMEK group (p = 0.56). Rebubble rates were 25% in the locally prestripped DMEK group and 19% in the imported DMEK group (p = 0.43). There was 1 primary graft failure in each group (p = 0.93). Endothelial cell density decreased by 37% in the locally prestripped DMEK group and by 33% in the imported DMEK group 2 years after transplantation. CONCLUSIONS: The long-term survivability of locally prepared DMEK grafts is comparable with that of DMEK grafts imported from American eye banks.

Intrastromal cannula injury in cataract surgery.

Iatrogenic ocular injuries from unexpected cannula ejection during ophthalmic surgery are rare and can cause vision-threatening damage. This report describes 2 cases of cannula-associated ocular injuries that resulted in good visual outcome, despite the cannula traveling intrastromally through the visual axis.

Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty in Eyes With a Glaucoma Drainage Device.

PURPOSE: To evaluate the feasibility and clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) in eyes with a glaucoma drainage device (GDD). DESIGN: Retrospective, interventional case series. METHODS: Clinical outcomes of 23 DMEK procedures for bullous keratopathy (52%), failed previous transplant (39%), or Fuchs endothelial corneal dystrophy (9%) in 20 eyes (19 patients) with a GDD were retrospectively analyzed at 2 tertiary referral centers. Main outcome measures were best-corrected visual acuity (BCVA), endothelial cell density (ECD), postoperative complications, and graft survival. RESULTS: Mean length of postoperative follow-up after DMEK was 19 (±17) months. Kaplan-Meier survival analysis showed an 89% cumulative graft success rate at 1 year postoperatively. At 1 year postoperatively (n = 15 eyes), BCVA improved by ≥2 Snellen lines in 11 eyes (73%) and remained stable in 4 eyes (27%). Donor ECD decreased by 37% (n = 14), 60% (n = 11), and 71% (n = 11) at 1, 6, and 12 months postoperatively, respectively. Postoperative complications up to 2 years postoperatively comprised pupillary block in 1 eye (successfully reversed by partial air removal), visually significant graft detachment requiring rebubbling in 5 eyes (22%), allograft rejection successfully reversed with topical steroids in 2 eyes (9%), secondary graft failure in 2 eyes (9%), and cataract in 1 of 3 phakic eyes (33%). Re-keratoplasty was required in 2 eyes (9%). CONCLUSIONS: With specific surgical modifications, DMEK provided acceptable clinical outcomes when taking the complexity of these eyes into account. However, presence of a GDD may reduce graft survival times and may pose a risk for more frequent regrafting.