Management of blebitis by members of the American Glaucoma Society: a survey

A Review on Pathogens and Necessary Diagnostic Work for Bleb-Related Infections (BRIs)

At the present time, as newer techniques and minimally invasive procedures gain popularity among anterior segment surgeons for regulating intraocular pressure, trabeculectomy still has a leading role in glaucoma surgery. Trabeculectomy retains a highly successful and safe profile; however, one of the major complications includes bleb-related infections (BRIs). To date, the most common pathogens remain Gram-positive cocci, but the list of pathogens that have been identified in the literature includes more than 100 microorganisms. Because antibiotic use is more widespread than ever before and our ability to identify pathogens has improved, the pathogen spectrum will broaden in the future and more pathogens causing BRIs will be described as atypical presentations. The scope of this review was to identify all pathogens that have been described to cause bleb-related infections to date, as well as focus on the risk factors, clinical presentation, and various available diagnostic tools used for an appropriate diagnostic workup.

Elderly woman with a bleb leak

Purpose

To describe a unique incidence of inadvertent filtering bleb creation after intravitreal injections.

Observations

An 84-year-old woman with a history of wet age-related macular degeneration requiring intravitreal injections presented with a Seidel-positive conjunctival cyst. The cyst was in an area where she had received multiple injections and was suspected to be an inadvertent filtering bleb secondary to a full-thickness scleral hole created by these injections. She underwent surgical closure of the fistula and repair of the bleb.

Conclusions and Importance

This case emphasizes the importance of recognizing this potential complication of intraocular injections and outlines steps that should be taken to prevent poor outcomes and vision loss.

Capnocytophaga canimorsus blebitis: case report and review of literature

Background

Capnocytophaga canimorsus is a facultative anaerobic, slow-growing, capnophilic, Gram-negative bacillus, that is commonly found in the microflora of canine and feline oral cavities. Capnocytophaga infections are an emerging zoonotic disease that can cause fatal systemic infections in immunocompromised individuals. Localized ocular Capnocytophaga infections, including keratitis, blepharitis, and endophthalmitis, can lead to severe eye threatening situations. To our knowledge, there is currently no documented case of Capnocytophaga canimorsus blebitis with bleb perforation after trabeculectomy.

Case presentation

Our case report and literature review features a novel case of Capnocytophaga blebitis that occurred after trabeculectomy, associated with close dog contact (i.e. face licking). The patient had underwent trabeculectomy 10 years prior and presented with conjunctival injection, perforated bleb, and hypotony. Overall, patient was medically treated subconjunctival vancomycin, gentamicin and moxifloxacin drops. Trabeculectomy revision was performed with good visual outcome. Bacterial cultures grew Capnocytophaga canimorsus.

Conclusions

We discuss the strategies for diagnosis, treatment, and common risk factors for ocular Capnocytophaga infections. At-risk patients with ocular infections should be asked about close contact with dogs and cats; and treated promptly with the proper antibiotic regimen.

Understanding practice patterns of glaucoma sub-specialists in India

AIM

To obtain information on the prevailing practice patterns of glaucoma specialists in India.

METHODS

Glaucoma specialists attending the Annual Conference of the Glaucoma Society of India (GSI) were surveyed. This survey, conducted in 2013, was based on an interactive audience response system.

RESULTS

The information was obtained from 146 glaucoma specialists. Approximately half (n=83; 57%) had ≥10y of experience in managing glaucoma and were in institutional practice (n=74, 51%). Goldmann applanation tonometry was preferred by 103 (72%) specialists whilst n=25 (17.4%) used non-contact tonometer. Indentation gonioscopy was favoured by two-thirds (n=90, 66%) whereas stereoscopic optic disc examination and visual fields using Humphrey perimeter was performed by a majority of the specialists surveyed (n=115, 86% and n=114; 83% respectively). Nearly three quarter specialists (n=96; 72%) preferred optical coherence tomography for imaging. The primary choice for treatment of angle closure disease and primary open angle glaucoma was laser (iridotomy, n=117; 93%) and medical management (prostaglandin analogue, n=104; 78%), respectively. Approximately only a third of the specialists surveyed (n=37; 28%) were performing both trabeculectomy and implantation of a glaucoma drainage device and about half (n=64; 47%) were not operating on congenital glaucoma at all.

CONCLUSION

This survey has found conformance with preferred practice patterns in several areas of diagnosis and management of glaucoma, but there was diversity in a few areas. The information is a significant step towards improvement of glaucoma care in India, including planning for future strategies.

Practice Preferences for Glaucoma Surgery: A Survey of the American Glaucoma Society

PURPOSE

The purpose of this study is to assess surgical practice patterns among the American Glaucoma Society (AGS) membership.

METHODS

An anonymous online survey evaluating the use of glaucoma surgeries in various clinical settings was redistributed to AGS members. Survey responses were compared with prior results from 1996, 2002, and 2008 to determine shifts in surgical practice patterns. Questions were added to assess the preferred approach to primary incisional glaucoma surgery and phacoemulsification combined with glaucoma surgery.

RESULTS

A total of 252 of 1091 (23%) subscribers to the AGS-net participated in the survey. Percentage use (mean±SD) of trabeculectomy with mitomycin C (MMC), glaucoma drainage device (GDD), and minimally invasive glaucoma surgery (MIGS) as an initial surgery in patients with primary open angle glaucoma was 59%±30%, 23%±23%, and 14%±20%, respectively. Phacoemulsification cataract extraction alone was the preferred surgical approach in 44%±32% of patients with primary open angle glaucoma and visually significant cataract, and phacoemulsification cataract extraction was combined with trabeculectomy with MMC in 24%±23%, with MIGS in 22%±27%, and with GDD in 9%±14%. Although trabeculectomy was selected most frequently to surgically manage glaucoma in 8 of 8 clinical settings in 1996, GDD was preferred in 7 of 8 clinical settings in 2016.

CONCLUSIONS

The use of GDD has increased and that of trabeculectomy has concurrently decreased over the past 2 decades. Trabeculectomy with MMC is the most popular primary incisional surgery when performed alone or in combination with phacoemulsification cataract extraction. Surgeons frequently manage coexistent cataract and glaucoma with cataract extraction alone, rather than as a combined cataract and glaucoma procedure.

Prevalent practice patterns in glaucoma: Poll of Indian ophthalmologists at a national conference

Purpose:

The aim of this study is to explore and compare the prevailing practice patterns in the diagnosis and management of glaucoma among subspecialists and general ophthalmologists in India.

Materials and Methods:

This is an interactive audience response system (ARS) based poll of ophthalmologists attending the annual conference of the Glaucoma Society of India in 2013.

Results:

The information was obtained from 379 ophthalmologists (146 glaucoma specialists, 54 nonglaucoma subspecialists, and 179 general ophthalmologists). The majority of polled ophthalmologists (236; 62%) had 10 or more years of experience in ophthalmology. The glaucoma specialists differed from nonglaucomatologists in their preference for Goldmann applanation tonometer (P < 0.01), four-mirror gonioscope (P < 0.01), Humphrey perimeter (P < 0.01), laser peripheral iridotomy in primary angle closure disease (P = 0.03), postiridotomy gonioscopy (P < 0.01), and usage of antifibrotic agents during filtering surgery (P < 0.01). Optical coherence tomography was the most preferred imaging modality and was utilized more often by the subspecialists than general ophthalmologists. The ophthalmologists also differed in their choice of antiglaucoma medications. More glaucoma specialists were performing surgery on children with congenital glaucoma (P < 0.01), implanting glaucoma drainage devices (P < 0.01), and using scientific journals to upgrade knowledge (P = 0.03) than the other ophthalmologists.

Conclusions:

This poll is the first of its kind in India, in its usage of the ARS, and in comparing the practice patterns of care for glaucoma among subspecialists and general ophthalmologists. It has revealed substantial diversity in a few areas among those who did and did not receive specialty training in glaucoma.

Current Perspectives of Prophylaxis and Management of Acute Infective Endophthalmitis

Endophthalmitis is an intraocular inflammatory condition which may or may not be caused by infective agents. Noninfectious (sterile) endophthalmitis may be attributable to various causes including postoperative retained soft lens matter or toxicity following introduction of other agents into the eye. Infectious endophthalmitis is further subdivided into endogenous and exogenous. In endogenous endophthalmitis there is hematogenous spread of organisms from a distant source of infection whereas in exogenous endophthalmitis direct microbial inoculation may occur usually following ocular surgery or penetrating eye injury with or without intraocular foreign bodies. Acute infective endophthalmitis is usually exogenous induced by inoculation of pathogens following ocular surgery, open-globe injury and intravitreal injections. More infrequently the infective source is internal and septicemia spreads to the eye resulting in endogenous endophthalmitis. Several risk factors have been implicated including immunosuppression, ocular surface abnormalities, poor surgical wound construction, complicated cataract surgery with vitreous loss and certain types of intraocular lens. Comprehensive guidelines and recommendations on prophylaxis and monitoring of surgical cases have been proposed to minimize the risk of acute endophthalmitis. Early diagnosis and prompt management of infective endophthalmitis employing appropriately selected intravitreal antibiotics are essential to optimize visual outcome.

Bleb-related infection revisited: a literature review

Bleb-related infection (BRI) is one of the serious complications of glaucoma filtering surgery. This literature review is aimed at the evaluation of recent studies related to BRI. The review presented and discussed risk factors, and clinical and laboratory diagnosis emphasizing advances in diagnostic techniques to detect and distinguish the disease as well as to initiate immediate intensive antibacterial treatment. Clinical features of recognized prognostic factors of visual outcome were also presented. The studies showed that the prognosis of blebitis is usually good, unless infection has progressed to endophthalmitis that would signify a poorer prognosis. Despite prompt and intensive treatment of patients with bleb-related endophthalmitis, the outcomes remain unsatisfactory especially with virulent organisms and low initial visual acuity. It has been recommended that early detection and treatment of risk factors and thorough patient education are indispensable in ensuring best prognosis in post-trabeculectomy patients.

Nocardia exalbida blebitis: a case report

PURPOSE

To report the first documented case of Nocardia exalbida blebitis.

METHODS

A 57-year-old immunocompetent African American man with a long-standing history of open-angle glaucoma in both eyes treated with trabeculectomy presented with a diffusely hyperemic, thin, cystic, leaky bleb with no discharge in his left eye. The patient underwent bleb revision using an amniotic membrane patch graft followed by 1 month of antibiotics. He presented second time with an inflamed eye and brisk leakage and underwent a second bleb revision. His cultures remained negative. Two months after this second surgery, an anterior staphyloma had formed within the bleb area, and visible leakage of purulent material and a dense hypopyon was noted. Gram stain of the material showed rare long-branching rods. The material was sent to an outside laboratory for culture and identification.

RESULTS

All 6 cultures were positive for N. abscessus complex and N. exalbida. The patient underwent 6 months of Bactrim therapy with topical sulfonamide and amikacin, leading to the disappearance of the hypopyon and an inflammation-free eye.

CONCLUSIONS

N. exalbida is a newly identified Nocardia species that must be considered as a possible infectious agent in immunocompetent patients with blebitis refractive to initial topical antibiotic therapy. Delay in diagnosis and initiation of appropriate antibiotic regimen can result in an aggressive inflammatory process and vision loss.

Endophthalmitis: state of the art

Endophthalmitis is an uncommon diagnosis but can have devastating visual outcomes. Endophthalmitis may be endogenous or exogenous. Exogenous endophthalmitis is caused by introduction of pathogens through mechanisms such as ocular surgery, open-globe trauma, and intravitreal injections. Endogenous endophthalmitis occurs as a result of hematogenous spread of bacteria or fungi into the eye. These categories of endophthalmitis have different risk factors and causative pathogens, and thus require different diagnostic, prevention, and treatment strategies. Novel diagnostic techniques such as real-time polymerase chain reaction (RT-PCR) have been reported to provide improved diagnostic results over traditional culture techniques and may have a more expanded role in the future. While the role of povidone-iodine in prophylaxis of postoperative endophthalmitis is established, there remains controversy with regard to the effectiveness of other measures, including prophylactic antibiotics. The Endophthalmitis Vitrectomy Study (EVS) has provided us with valuable treatment guidelines. However, these guidelines cannot be directly applied to all categories of endophthalmitis, highlighting the need for continued research into attaining improved treatment outcomes.

Characterisation of ilomastat for prolonged ocular drug release

We are developing tablet dosage forms for implantation directly into the subconjunctival space of the eye. The matrix metalloproteinase inhibitor, ilomastat, has previously been shown to be efficacious at suppressing scarring following glaucoma filtration surgery (GFS). We report on the physical characterisation of ilomastat which is being developed for ocular implantation. Since ilomastat is being considered for implantation it is necessary to examine its polymorphs and their influence on aspects of the in vitro drug release profile. X-ray powder diffraction identified two polymorphs of ilomastat from different commercial batches of the compound. Tablets were prepared from the two different polymorphs. Isothermal perfusion calorimetry was used to show that amorphous content is not increased during tablet formulation. The melting points of the two polymorphs are 188 and 208°C as determined by differential scanning calorimetry. Utilising single crystal X-ray diffraction, the structural conformations and packing arrangements of the different polymorphs were determined. The orthorhombic crystal crystallised as a monohydrate while the second monoclinic crystal form is non-solvated. Ilomastat tablets prepared from the two different solid forms exhibited similar drug release profiles in vitro under conditions mimicking the aqueous composition, volume and flow of the subconjunctival space after GFS. This suggests that a reproducible dose at each time point during release after implantation should be achievable in vivo with ilomastat tablets prepared from the two polymorphs identified.

Etiology and epidemiological analysis of glaucoma-filtering bleb infections in a tertiary eye care hospital in South India

Purpose:

To evaluate the microbial etiology and associated risk factors among patients with blebitis following trabeculectomy.

Materials and Methods:

A retrospective analysis of all culture-proven blebitis was performed in patients who underwent trabeculectomy between January 2004 and December 2008. A standardized form was filled out for each patient, documenting sociodemographic features and information pertaining to risk factors. Swabbing of the infected bleb surface was performed for all suspected cases and further subjected to microbiological analysis.

Results:

A total of 23 patients with culture-proven blebitis were treated during the study period, with a mean age of 59.2 years (59.2 ± SD: 12.8; range, 30-81 years). Duration of onset was early (≤36 months) in six (26%) cases and late (> 36 months) in 17 (74%) cases with a range between 15 and 144 months (mean, 82.91 months; SD: 41.89). All 23 blebs were located superiorly and of which, 21 (91%) were microcystic avascular, 1 (4%) diffuse avascular, and 1 (4%) vascular flattened. The predominant risk factor identified was bleb leak (35%; 8 of 23) followed by thin bleb (22%; 5 of 23) and blepharitis (17%; 4 of 23). Bleb leaks (100%) were recorded only in patients with late onset (≥ 9 years) of infection (P< 0.001), while the incidence of ocular surface disease (100%) occurred early (≤3 years) (P< 0.001). Use of topical steroids was associated frequently with cases of thin blebs (80%; 4 of 5) (P< 0.001), while topical antibiotics showed bleb leaks (88%; 7 of 8) (P< 0.001). Coagulase-positive staphylococci were frequently recovered from blebitis with thin blebs (71%; 5 of 7) (P = 0.001), Coagulase-negative staphylococci (CoNS) with bleb leak (100%; 8 of 8) (P< 0.001), Corynebacterium with blepharitis (100%; 3 of 3) (P = 0.001), and Streptococci with releasable sutures (75%; 3 of 4) (P = 0.001).

Conclusion

Bleb leak is the principal risk factor responsible for late-onset blebitis, while early-onset blebitis could be ascribed to ocular surface diseases. Streptococci were mainly responsible for early onset of infection, while the late onset was due to CoNS.

Complications of inadvertent filtering blebs after cataract extraction

We report 2 cases of inadvertent filtering blebs that developed vision-threatening complications many years after uneventful cataract extraction with scleral incisions. These inadvertent blebs can create complications similar to the intentionally produced blebs from trabeculectomy surgery; thus, follow-up and management should be handled in a similar manner.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Resident Glaucoma Surgical Training in United States Residency Programs

PURPOSE

To determine current trends in resident glaucoma surgical training throughout the United States.

METHODS

A comprehensive survey was sent to the residency director of all 121 ACGME-accredited ophthalmology training programs in the United States.

RESULTS

The mean and median number of glaucoma procedures a resident will complete by the end of their training is 8.6 and 8 respectively for trabeculectomy, 5.3 and 4 for combined trabeculectomy/phacoemulsification, and 3.6 and 2 for tube-shunts. One percent of residents will gain experience as primary surgeon on trabeculectomies during their first year, 32% during their second year, and 67% during their third year. Seventy-five percent of residents are taught more than one trabeculectomy technique by more than one staff surgeon. Eighty-four percent of residents are taught glaucoma surgery almost exclusively by fellowship-trained glaucoma surgeons. Eighty-two percent of residents use antimetabolites (mitomycin C or 5-FU) as an adjunct to trabeculectomy most or all of the time. More than 96% of resident tube-shunt procedures use Ahmed, Baerveldt, or Molteno devices. Eighty percent of residents do not perform any pediatric glaucoma surgeries. Sixty-two percent of residents rotate out of their main facility to perform glaucoma surgery.

CONCLUSIONS

Residents are being exposed to glaucoma surgery early in their residency training. Most are performing a variety of different procedures and techniques, and are taught by fellowship-trained surgeons. Residents gain very little exposure to pediatric glaucoma surgery. All programs reported compliance with minimum RRC requirements for glaucoma filtering surgery.

Glaucoma-filtering bleb infections

PURPOSE OF REVIEW

To present a review of the current literature regarding the management of glaucoma-filtering bleb infections.

RECENT FINDINGS

With the increased use of intraoperative antifibrotic (eg, mitomycin and fluorouracil) as an adjunct to standard trabeculectomy, an increased incidence is seen of late-onset filtering bleb-related infections. These infections range from infections localized to the bleb (blebitis) to endophthalmitis. Risk factors for bleb-related infections include an inferior or nasally located bleb; presence of a high bleb or blepharitis; development of a late-onset bleb leak; use of antifibrotic agents; chronic antibiotic use; and performance of a trabeculectomy alone versus a combined procedure.

SUMMARY

The optimal treatment for bleb-related infections is evolving, but consensus is that a high degree of vigilance and aggressive treatment are key to minimizing the potentially blinding nature of this complication. It is important to note that those glaucoma procedures that provide the lowest intraocular pressure are often those that predispose to bleb-related infections.