Big bubble deep anterior lamellar keratoplasty for management of deep fungal keratitis

Post-Keratoplasty Microbial Keratitis in the Era of Lamellar Transplants-A Comprehensive Review

Microbial keratitis in a post-transplant cornea should be considered a distinct entity from microbial keratitis in a non-transplant cornea. Firstly, the use of immunosuppressive treatments and sutures in corneal transplants changes the etiology of keratitis. Secondly, corneal transplant has an impact on corneal biomechanics and structure, which facilitates the spread of infection. Finally, the emergence of lamellar transplants has introduced a new form of keratitis known as interface keratitis. Given these factors, there is a clear need to update our understanding of and management strategies for microbial keratitis following corneal transplantation, especially in the era of lamellar transplants. To address this, a comprehensive review is provided, covering the incidence, risk factors, causes, and timing of microbial keratitis, as well as both clinical and surgical management approaches for its treatment in cases of penetrating and lamellar corneal transplants.

Comparison of therapeutic effects between big-bubble deep anterior lamellar keratoplasty and penetrating keratoplasty for medically unresponsive Acanthamoeba keratitis

PURPOSE

To compare the outcomes of big-bubble deep anterior lamellar keratoplasty (BB-DALK) and penetrating keratoplasty (PKP) in the management of medically unresponsive Acanthamoeba keratitis (AK).

METHODS

This retrospective study included 27 eyes of BB-DALK and 24 eyes of PKP from a tertiary ophthalmology care centre. Glucocorticoid eye drops were subsequently added to the treatment plan 2 months postoperatively based on the evaluation using confocal laser scanning microscopy. The clinical presentations, best-corrected visual acuity (BCVA), postoperative refractive outcomes, graft survival, and Acanthamoeba recurrence were analyzed.

RESULTS

The AK patients included in the study were in stage 2 or stage 3, and the percentage of patients in stage 3 was higher in the PKP group (P = 0.003). Clinical presentations were mainly corneal ulcers and ring infiltrates, and endothelial plaques, hypopyon, uveitis and glaucoma were more common in the PKP group (P = 0.007). The BCVA and the graft survival rate showed no statistically significant differences between the two groups at 1 year after surgery. However, 3 years postoperatively, the BCVA of 0.71 ± 0.64 logMAR, the graft survival rate of 89.5%, and the endothelial cell density of 1899 ± 125 cells per square millimeter in the BB-DALK group were significantly better than those of the PKP group (P = 0.010, 0.046, and 0.032, respectively). 3 eyes (11.1%) in the BB-DALK group and 2 eyes (8.3%) in the PKP group experienced Acanthamoeba recurrence, but the rates showed no statistically significant difference between the two groups (P = 1.000). In the PKP group, immune rejection and elevated intraocular pressure were observed in 5 and 6 eyes, respectively.

CONCLUSION

Corneal transplantation is recommended for AK patients unresponsive to antiamoebic agents. The visual acuity and graft survival can be maintained after BB-DALK surgery. Acanthamoeba recurrence is not related to the surgical approach performed, whereas complete dissection of the infected corneal stroma and delayed prescribing of glucocorticoid eye drops were important to prevent recurrence.

Fungal Keratitis: Diagnosis, Management, and Recent Advances

Fungal keratitis is one of the major causes of microbial keratitis that may lead to corneal blindness. Many problems related to diagnosis and therapy are encountered in fungal keratitis, including difficulty in obtaining laboratory diagnoses and the availability and efficacy of antifungal medications. Intensive and prolonged use of antifungal topical preparations may not be enough. The use of antifungal medications is considered the main treatment for fungal keratitis. It is recommended to start antifungal therapy after confirmation of the clinical diagnosis with a smear or positive cultures. Topical application of antifungal medications is a mainstay for the treatment of fungal keratitis; however, systemic, intra-stromal, or intra-cameral routes may be used. Therapeutic keratoplasty is the main surgical procedure approved for the management of fungal keratitis with good success rate. Intrastromal corneal injection of antifungal medications may result in steady-state drug levels within the corneal tissue and prevent intervals of decreased antifungal drug concentration below its therapeutic level. In cases of severe fungal keratitis with deep stromal infiltration not responding to treatment, intracameral injection of antifungal agents may be effective. Collagen cross-linking has been proposed to be beneficial for cases of fungal keratitis as a stand-alone therapy or as an adjunct to antifungal medications. Although collagen cross-linking has been extensively studied in the past few years, its protocol still needs many modifications to optimize UV fluence levels, irradiation time, and concentration of riboflavin to achieve 100% microbial killing.

Surgical management of infectious keratitis

The successful management of infectious keratitis is usually achieved with a combination of tools for accurate diagnosis and targeted timely antimicrobial therapy. An armamentarium of surgical interventions is available in the acute stage which can be resorted to in a step wise manner or in combination guided by the response to treatment. Simple surgical modalities can facilitate accurate diagnosis e.g. corneal biopsy and alcohol delamination. Surgery to promote epithelial healing can vary from tarsorrhaphy, amniotic membrane transplantation or conjunctival flaps depending on the extent of infection, visual prognosis, availability of tissue and surgeon's experience. Collagen crosslinking has been increasingly utilized with successful results to strengthen the cornea and reduce the infective load consequently the need for further elaborate surgical interventions. It has shown encouraging results specially in superficial bacterial and fungal keratitis but for deeper infections, viral and acanthamoeba keratitis, its use remains questionable. When globe integrity is compromised, corneal gluing is the most commonly used procedure to seal small perforations. In larger perforations/fulminant infections a tectonic/therapeutic graft is advisable. Partial thickness grafts are increasingly popular to treat superficial infection or internally tamponade perforations. Peripheral therapeutic grafts face challenges with potential requirement for a manually fashioned graft, and increased risk of rejection due to proximity to the limbal vessels. Late stage visual rehabilitation is likely to require further surgical interventions after complete resolution of infection and inflammation. A preliminary assessment of corneal sensation and integrity of the ocular surface are key for any successful surgical intervention to restore vision.

Characteristics of In Vitro Culture and In Vivo Confocal Microscopy in Patients with Fungal Keratitis in a Tertiary Referral Hospital in Central China

PURPOSE

To investigate the characteristics of in vitro culture and in vivo confocal microscopy (IVCM) in patients with fungal keratitis (FK) presented in a tertiary referral hospital in central China.

METHODS

In this noncomparative retrospective study, patients with the diagnosis of FK between October 2021 and November 2022 were reviewed. An IVCM and fungal culture (corneal scraping specimens) were performed, and the characteristics were analyzed.

RESULTS

During October 2021 and November 2022, 85 patients were diagnosed with FK. From 63 culture-positive cases, 8 species of fungus were identified. The proportions of isolated fungal species were Fusarium and Aspergillus equally accounting for 33.3% (21 of 63), Alternaria 9.5% (6 of 63), Curvularia 6.3% (4 of 63), Scedosporium apiospermum 6.3% (4 of 63), Paecilomyces lilacinus 3.2% (2 of 63), Exserohilum 3.2% (2 of 63), and Candida 4.8% (3 of 63), respectively. In positive culture cases, IVCM was found to be positive for hyphae or spores in 61 of 63 patients (96.8%). Different fungal species had a variety of cultural characteristics and IVCM manifestations.

CONCLUSIONS

In a tertiary referral hospital in central China, Fusarium species, Aspergillus species, and Alternaria species were the 3 most common isolated fungal pathogens, and the proportion of Aspergillus species was significantly higher than that in other regions of China. Careful lesion depth examination by IVCM and OCT should be taken before lamellar keratoplasty to avoid postoperative recurrence. Identifying the IVCM image and culture characteristics will facilitate rapid diagnosis and proper treatment, but IVCM cannot yet replace fungal cultures to distinguish between different fungal species.

Outcomes of Severe Fungal Keratitis Using in vivo Confocal Microscopy and Early Therapeutic Penetrating Keratoplasty

Purpose

The purpose of this study was to assess the impact of early diagnosis using in vivo confocal microscopy and early therapeutic penetrating keratoplasty (TPK) on the outcomes of severe cases of fungal keratitis.

Methods

This retrospective single-center study included 38 patients (40 eyes) with fungal keratitis who presented between December 2013 and February 2020. Preoperative, intraoperative, and postoperative parameters were recorded to assess the role of early correct diagnosis and early surgical therapy on visual acuity outcome and enucleation rate during follow-up.

Results

The mean patient age was 51 years (71% females). The initial external diagnosis was correct in 20 cases (50%). The mean time from symptom onset until admission to our department was 46.8 ± 68.0 (median 28.5) days. The mean time to correct diagnosis after admission to our department was 1 day with in vivo confocal microscopy (IVCM). IVCM was performed in 38 cases, of which 36 (sensitivity: 94.7%) were positive for fungal infection. Twenty-seven out of 40 (67.5%) eyes received a TPK 4.2 ± 3.9 days after admission, with a mean graft size of 8.9 ± 1.9 mm. Three eyes (7.5%) were enucleated. The corrected distance visual acuity of the entire study population increased from 2.0 ± 1.2 LogMAR to 0.96 ± 1.17 LogMAR.

Conclusion

In vivo confocal microscopy is a powerful tool for the early detection of fungal organisms in infectious keratitis. An early TPK with a large graft helps to eradicate the infection timely and results in a favorable visual acuity outcome and lower enucleation rate, especially when treating filamentous fungi.

Comparison of complications and visual outcomes between big-bubble deep anterior lamellar keratoplasty and penetrating keratoplasty for fungal keratitis

BACKGROUND

To compare the postoperative complications and visual outcomes of big-bubble deep anterior lamellar keratoplasty (BB-DALK) and penetrating keratoplasty (PK) for fungal keratitis (FK).

METHODS

This retrospective study included 94 cases of BB-DALK for FK and 161 cases of PK for FK from a tertiary ophthalmology care centre.

RESULTS

The most common FK pathogens were Fusarium (n = 84, 32.9%) and Aspergillus (n = 67, 26.3%). The recurrence rates after BB-DALK and PK were 3.2 and 5%, respectively (p = 0.723). The follow-up duration was 31.9 ± 15.8 months in the BB-DALK group and 33.9 ± 15.0 months in the PK group. The immune rejection rate was significantly lower in the BB-DALK group than in the PK group (1.1 vs. 18.6%, p < 0.001), as was the incidence of secondary glaucoma (p = 0.018). Endothelial cell density in the BB-DALK group tended to be stable at postoperative month 6, whereas the PK group still attenuated at a hyper-physiological rate. Postoperative best-corrected visual acuity (BCVA) significantly improved in both groups (p < 0.001). No significant difference between-group was observed in BCVA, refractive cylinder, and spherical equivalent postoperatively.

CONCLUSION

Big-bubble DALK is a useful and safe alternative to PK for medically uncontrolled FK.

Survey report on keratoplasty in China: A 5-year review from 2014 to 2018

To provide the general information on corneal transplantation (CT) in China, China Cornea Society designed a questionnaire on CT from 2014 to 2018 and entrusted it to 31 committee members for implementation of the survey nationwide. This article presents the results of the survey and compares the indicators used in the survey and those in the annual statistical report released by the Eye Bank Association of America (EBAA). The number of corneal transplantations completed by the 64 hospitals from 2014 to 2018 was respectively 5377, 6394, 7595, 8270 and 8980, totally 36,616 (22,959 male and 13,657 female). The five largest hospitals by the number of corneal transplantations completed 15,994 surgeries in total, accounting for 43.68% of all the surgeries performed in the 64 hospitals. The most common indication for corneal transplantations was corneal leukoma (7683, 20.98%), followed by bacterial keratitis (4209, 11.49%), corneal dystrophies (4189, 11.44%), keratoconus (3578, 9.77%) and corneal perforation (2839, 7.75%). The main surgical techniques were penetrating keratoplasty (PK) (19,896, 54.34%), anterior lamellar keratoplasty (ALK) (13,869, 37.88%). The proportion of PK decreased from 57.97% in 2014 to 52.88% in 2018 while the proportion of ALK increased from 36.04% in 2014 to 37.92% in 2018. The geographical distribution of keratoplasties performed in China is unbalanced. PK and ALK were the main techniques of CT and corneal leukoma, bacterial keratitis and corneal dystrophies were the main indications for CT in China.

Endothelial Plaques as Sign of Hyphae Infiltration of Descemet's Membrane in Fungal Keratitis

Background

To evaluate the relationship between corneal endothelial plaques and fungal hyphae infiltration in fungal keratitis.

Methods

Retrospective cross-sectional study of 60 fungal keratitis patients who underwent keratoplasty between January 2013 and March 2017. The endothelial plaques were graded as follows: grade 1, 1–3 endothelial plaques; grade 2, 4–8 endothelial plaques; and grade 3, more than 8 endothelial plaques or dense, merging endothelial plaques. The fungal pathogen culture and histopathology of diseased Descemet's membrane were evaluated.

Results

According to endothelial plaque grading, 3 patients were grade 1, 29 patients were grade 2, and 28 patients were grade 3. The PK surgery was performed in 57 patients with endothelial plaques of grade 2 and grade 3 and DALK surgery in 3 patients of grade 1. The predominating fungal pathogens were Aspergillus species (63.2%). All 57 patients with grade 2 and grade 3 had fungal hyphae in Descemet's membrane based on calcofluor white staining or PAS staining. In patients with grade 3, more hyphae and inflammatory cells were found in Descemet's membrane. The immunohistochemical staining of endothelial plaques revealed that CD15 and CD68 were positive in most cells. During the follow-up, 2 out of 3 patients who underwent DALK had recurrent fungal keratitis.

Conclusions

Endothelial plaques are considered as a sign of hyphae infiltrating Descemet's membrane. PK should be performed once plaques are detected in endothelium during the surgery.

Clinical outcome after air-assisted manual deep anterior lamellar keratoplasty for fungal keratitis poorly responsive to medical treatment

Purpose

Fungal keratitis remains an important disorder because of difficulty in its diagnosis, and some patients do not respond to medical treatment using antifungal local and systemic agents. This study was carried out to determine the therapeutic value of air-assisted manual therapeutic deep anterior lamellar keratoplasty (TDALK) in the treatment of fungal keratitis not curable by antifungal chemotherapy.

Methods

Seventeen patients (18 eyes) who were referred to Fukuoka University Hospital and treated surgically from January 2006 to April 2018, in whom a diagnosis of fungal keratitis was confirmed by typical clinical findings and microbiological or histological analysis of corneal specimens, and who were poorly responsive to topical and systemic antifungal medication, whereas the lesion had not resulted in corneal perforation, were enrolled in this study and were treated by air-assisted manual TDALK. Clinical outcomes including treatment course, therapeutic success rate, visual acuity outcomes and graft clarity rate were analyzed.

Results

The most common pathogen was Fusarium, followed by Candida and Aspergillus. Beneficial therapeutic results (a clear or translucent graft) were achieved in 15 of 18 eyes (83%). There was no recurrence of infection and resulting visual acuity ≤0.15 logarithm of minimal angle of resolution unit was achieved in 15 eyes (83%). Intraoperative microperforation of Descemet’s membrane (DM) was not observed in any patients.

Conclusion

Air-assisted manual TDALK can be effective for treating severe fungal keratitis. In addition, air-assisted manual TDALK might be an alternative procedure to big-bubble DALK, because it can provide ambulatory vision and can preserve potentiality of vision with less risk of intraoperative perforation of DM.

Outcomes of therapeutic keratoplasty for severe infectious keratitis in Chongqing, a 16-year experience

Purpose

This study aimed to evaluate the outcomes of therapeutic keratoplasty for severe infectious keratitis in Chongqing (Southwest China).

Patients and methods

The records of 561 eyes that underwent therapeutic keratoplasty for refractory microbial keratitis from 2001 to 2016 were analyzed in this retrospective study. Data included demographic information, microbiological investigations, associated factors, graft size, preoperative status, postoperative complications, and final anatomical outcomes.

Results

Trauma was the most common cause (267, 47.6%) for corneal ulcers leading to therapeutic keratoplasty. The etiological diagnosis included bacterial keratitis (80 eyes, 14.3%), fungal keratitis (317 eyes, 56.5%), acanthamoeba keratitis (3 eyes, 0.5%), and mixed bacteria/fungal infection (15 eyes, 2.7%). Anatomical success was achieved for 492 eyes (87.7%), with bacterial keratitis having a better outcome than fungal and mixed infections. Diabetes and preoperative time ≥30 days were significantly associated with anatomical failure in the multivariate logistic regression (P=0.028 and P=0.022, respectively). Patients with hypopyon, corneal perforation, surgical delay, and/or large graft size had a higher incidence of postoperative complications (reinfection, cataract, glaucoma, hyphema, or graft rejection) (P<0.05).

Conclusion

Therapeutic keratoplasty was an effective procedure in managing refractory infectious keratitis. Prompt and appropriate surgery would result in fewer complications and better outcomes.

Etiology and failure analysis of anterior lamellar keratoplasty

AIM

To analyze indications and reasons for failure of anterior lamellar keratoplasty (ALK).

METHODS

The clinical records were retrospectively reviewed. Main outcome measures included indications for ALK and reasons for failure of ALK.

RESULTS

A total of 434 patients (462 eyes) were treated with ALK at Qingdao Eye Hospital, Shandong Eye Institute from June 1, 2009 to May 31, 2016. The main indications were infectious keratitis (33.3%), keratoconus (23.6%), corneal dystrophy and degeneration (9.8%), Mooren's ulcer (8.4%), corneal neoplasm (7.8%), viral keratitis (6.5%) and regrafting (3.7%). Fungal keratitis accounted for 73.4% in the infectious keratitis cases. ALKs were failed in 36 patients, with the major causes being recurrence of primary diseases (63.9%). The leading causes of graft failure was Mooren's ulcer (36.1%), followed by infectious keratitis (30.6%). Recurrence of fungal keratitis accounted for 81.8% in the failed cases after ALK for infectious keratitis cases.

CONCLUSION

Infectious keratitis and keratoconus are the main indications for ALK, of which fungal keratitis was the major cause of corneal infections. Recurrence of primary disease is the main reason of graft failure after ALK, in which the main primary diseases associated with graft failure are Mooren's ulcer and fungal keratitis.

Early deep anterior lamellar keratoplasty for fungal keratitis poorly responsive to medical treatment

PurposeTo investigate the efficacy of early therapeutic deep anterior lamellar keratoplasty (DALK) in eradicating fungal keratitis that is poorly responsive to medical treatment.Patients and methodsTwenty-three eyes (23 patients) underwent early therapeutic DALK within 15 to 50 days from the onset of symptoms. The adopted eligibility criteria for early DALK included the following: active fungal keratitis affecting the optical zone with ulcer confined in the 6.00 mm central cornea; deeper than 150 μm but not exceeding 300 μm; and poorly responsive to medical treatment.ResultsThe big bubble technique was accomplished in 74% (17) of eyes, whereas manual dissection was performed in the remaining 26% (6) of eyes. Histopathological examination did not show any sign of fungal colonization in the peripheral and deep stromal lamellae in any case. All grafts were transparent postoperatively, and no recurrence of infection occurred. Median best spectacle corrected visual acuity significantly improved from 2.0 (1.0 interquartile range) logMAR to 0.1 (0.1 interquartile range) logMAR (P<0.01). The mean follow-up was 32±10 months. Neither episode of rejection nor graft failure was noted during the follow-up period.ConclusionEarly DALK could represent a safe therapeutic approach to eradicate fungal keratitis that affects the optical zone and is poorly responsive to medical treatment.

Review of clinical and basic approaches of fungal keratitis

Fungal keratitis (FK) is a serious disease which can cause blindness. This review has current information about the pathogenesis, limitations of traditional diagnosis and therapeutic strategies, immune recognition and the diagnosis and therapy of FK. The information of this summary was reviewed regularly and updated as what we need in the diagnosis and therapy of FK nowadays.

Clinical evaluation of deep anterior lamellar keratoplasty using glycerol-cryopreserved corneal tissues for refractory herpetic stromal keratitis: An observational study

The study aimed to evaluate the therapeutic effects of deep anterior lamellar keratoplasty (DALK) using glycerol-cryopreserved corneal tissues (GCCTs) in patients with refractive herpes simplex keratitis (HSK). This article was a retrospective, noncomparative, and interventional case series. Patients with HSK underwent DALK using GCCTs at Shanghai Tongji Hospital from 2012 to 2015. The best spectacle corrected visual acuity, recurrent inflammation, graft status, postoperative central graft thickness, and pre/postoperative complications were detected. The follow-up ranged from 24.4 ± 5.6 months (range: 16-38 months). Overall, the best spectacle corrected visual acuity was increased from HM/10 cm to 0.15 before surgery to 0.41 ± 0.14 (range: 0.1-0.8; P < 0.05) at 12 months postoperatively. Intraoperative microperforation occurred in 4 eyes (14.81%), and rejection episodes were encountered in 3 of 27 eyes (11.1%), and all of the eyes reversed. HSK recurred in 2 eyes (7.41%), 1 eye with repeated recurring HSK, and eventually led to perpetual corneal opacity and the patient refused a retransplantation. The mean entire corneal thickness was 0.519 ± 0.018 mm (range: 0.5-0.56 mm) and the mean graft thickness was 0.405 ± 0.033 mm (range: 0.35-0.47 mm) in the final follow-up. The DALK using GCCTs was proven to be an effective and safe therapy in treating refractory HSK.

Surgical management of corneal infections

PURPOSE OF REVIEW

The purpose of this review is to discuss the options for, and recent developments in, the surgical treatment of corneal infections. Although the mainstay of treatment of corneal infections is topical antimicrobial agents, surgical intervention may be necessary in a number of cases. These include advanced disease at presentation, resistant infections, and progressive ulceration despite appropriate treatment. Prompt and appropriate treatment can make the difference between a good outcome and loss of vision or the eye.

RECENT FINDINGS

There are a number of surgical therapies available for corneal infections. Preferred therapeutic modalities differ based on the size, causation, and location of the infection but consist of either replacement of the infected tissue or structural support of the tissue to allow healing. Although there are no completely novel therapies that have been developed recently, there have been incremental improvements in the existing treatment modalities making them more effective, easier, and safer.

SUMMARY

Several options are available for surgically managing corneal infections. Ophthalmologists should select the optimal procedure based on the individual patient's situation.

VIDEO ABSTRACT

http://links.lww.com/COOP/A20.