Infectious keratitis outbreak after laser in situ keratomileusis at a single laser center in Japan

Changes in cataract and refractive surgery practice patterns among JSCRS members over the past 20 years

PURPOSE

To evaluate changes in cataract and refractive surgery practice patterns among members of the Japanese Society of Cataract and Refractive Surgery (JSCRS) over the past 20 years.

STUDY DESIGN

Questionnaire survey study.

SUBJECTS AND METHODS

Clinical surveys were conducted annually between February and April from 2004 to 2023. Survey questions covered various areas, including cataract surgical techniques, anesthesia, endophthalmitis prophylaxis, toric and presbyopia-correcting intraocular lenses (IOLs), complications, and refractive surgery.

RESULTS

The highest (n=554 [36.8%]) and lowest (n=316 [19.1%]) numbers of responses were collected in 2012 and 2016, respectively. In perioperative management, the intraoperative use of polyvinyl alcohol-iodine solution and topical antibiotic prescription 3 days before surgery has increased. The use of intracameral injection at the end of surgery has also significantly increased, although it has not been established as common practice. In anesthesia, there is a clear polarization between the use of topical drops and tenon injection. The use of toric IOLs and presbyopia-correcting IOLs has significantly increased from 2010 to 2023. In the latter, the use of trifocal IOLs has particularly increased. Regarding IOL power calculations, the Barrett True K and the Barrett Universal II formulas are rapidly gaining popularity for application with and without post-laser vision correction, respectively. In refractive surgery, phakic IOLs and corneal refractive therapy have attracted considerable interest, followed by laser in situ keratomileusis.

CONCLUSIONS

Evaluation of annual clinical survey data over the past two decades provided valuable insights into the shifting practice patterns and clinical opinions among JSCRS members.

Ocular infections associated with atypical mycobacteria: A review

Atypical mycobacteria or non-tuberculous mycobacteria (NTM) are a group of acid-fast bacteria that are pathogenic to different parts of the eye. The organisms can cause a spectrum of ocular infections including keratitis, scleritis, uveitis, endophthalmitis and orbital cellulitis. Trauma, whether surgical or nonsurgical, has the highest correlation with development of this infection. Common surgeries after which these infections have been reported include laser in situ keratomileusis (LASIK) and scleral buckle surgery. The organism is noted to form biofilms with sequestration of the microbe at different inaccessible locations leading to high virulence. Collection of infective ocular material (corneal scraping/necrotic scleral tissue/abscess material/vitreous aspirate, etc.) and laboratory identification of the organism through microbiologic testing are vital for confirming presence of the infection and initiating treatment. In cluster infections, tracing the source of infection in the hospital setting via testing of different in-house samples is equally important to prevent further occurrences. Although the incidence of these infections is low, their presence can cause prolonged disease that may often be resistant to medical therapy alone. In this review, we describe the various types of NTM-ocular infections, their clinical presentation, laboratory diagnosis, management, and outcomes.

Infectious Keratitis After Keratorefractive Surgery: Update and Review of the Literature

OBJECTIVES

To summarize the clinical manifestations, microbiological profile, treatment, and prognosis of corneal infections after different keratorefractive surgery.

METHODS

To obtain relevant studies, English-language databases, including PubMed, Ovid Embase, Web of Science, and CLNAHL, were searched from January 1979 to March 2022. The fundamentals of the literature, clinical characteristics, pathogens, and treatments were retrieved for each included article.

RESULTS

Eighty-four studies involving 306 infectious eyes were included in this review. Risk factors of potential infection included a history of blepharitis, contact lens usage, and contaminated surgical instruments. The mean onset time was 22.9±38.7 days (range: 1 day to 3 years). The most common organism isolated from infectious keratitis after keratorefractive surgery were Staphylococcus aureus , followed by Mycobacterium and coagulase-negative Staphylococcus . Most of the infections after refractive procedures were sensitive to medical treatment alone, and the ultimate best-corrected visual acuity after medical treatment was as follows: 20/20 or better in 82 cases (37.0%), 20/40 or better in 170 cases (76.5%), and worse than 20/40 in 52 cases (23.5%). Surgical interventions including flap lift, flap amputation, ring removal, and keratoplasty were performed in 120 eyes (44.5%).

CONCLUSIONS

Most infections after keratorefractive surgery occur within a week, whereas more than half of the cases after laser-assisted in situ keratomileusis happen after about a month. Gram-positive cocci and mycobacterium are the most common isolates. Infections after LASIK, intracorneal ring (ICR) implantation, and small incision lenticule extraction, which primarily occur between the cornea layers, require irrigation of the tunnels or pocket with antibiotics.

Atypical microbial keratitis

Atypical microbial keratitis refers to corneal infections caused by micro-organisms not commonly encountered in clinical practice. Unlike infections caused by common bacteria, cases of atypical microbial keratitis are often associated with worse clinical outcomes and visual prognosis. This is due to the challenges in the identification of causative organisms with standard diagnostic techniques, resulting in delays in the initiation of appropriate therapies. Furthermore, due to the comparatively lower incidence of atypical microbial keratitis, there is limited literature on effective management strategies for some of these difficult to manage corneal infections. This review highlights the current management and available evidence of atypical microbial keratitis, focusing on atypical mycobacteria keratitis, nocardia keratitis, achromobacter keratitis, and pythium keratitis. It will also describe the management of two uncommonly encountered conditions, infectious crystalline keratopathy and post-refractive infectious keratitis. This review can be used as a guide for clinicians managing patients with such challenging corneal infections.

Late onset of microbial keratitis after laser in situ keratomileusis surgery: case series

PURPOSE

To report predisposing factors, clinical features, microbiology spectrum, antibiotic resistance, antimicrobial therapy, and outcomes of patients with a previous laser in situ keratomileusis (LASIK) surgery and diagnosed with presumed microbial keratitis.

SETTING

Sydney Eye Hospital, Sydney, New South Wales, Australia.

DESIGN

Retrospective case review.

METHODS

Patients were identified from pathology and hospital coding data from 2012 to 2016. Inclusion criteria were all patients with a previous LASIK surgery, a presumed diagnosis of microbial keratitis, and a corneal scrape performed and aged older than 18 years. Demographics, clinical details, and outcomes were collated from the medical records.

RESULTS

Sixteen patients were included, with median age of 41.5 years (range 22 to 85 years) and 56.2% of women. The median time between LASIK procedure and microbial keratitis presentation was 38.3 months (interquartile range 6.7 to 77.45 months). Cultures were positive for bacteria in 12 (75%) of 16 scrapes. Of the bacterial isolates, 12 (85.7%) were gram-positive and 2 (14.3%) gram-negative. Sensitivity profiles for the isolated bacteria were similar between fortified antibiotics (cefalotin and gentamicin) and commercial products (chloramphenicol and ofloxacin). Complications included the need for tectonic grafts, nonhealing epithelial defects, thinning, and neovascularization.

CONCLUSIONS

Late onset of keratitis after LASIK can occur with no positive cultures for nontuberculous mycobacteria, no interface involvement, and no other usual features reported in case series of infectious keratitis in LASIK patients. It has a similar clinical course to non-LASIK keratitis, such that the surgery may not have been a risk factor for infection.

Keratitis following laser refractive surgery: Clinical spectrum, prevention and management

Laser refractive surgery (LRS) is one of the most demanding areas of ophthalmic surgery and high level of precision is required to meet outcome expectations of patients. Post-operative recovery is of vital importance. Keratitis occurring after LRS can delay visual recovery. Both surface ablations [Photorefractive keratectomy (PRK)] as well as flap procedures [Laser in-situ keratomileusis (LASIK)/Small incision lenticule extraction] are prone to this complication. Reported incidence of post-LRS infectious keratitis is between 0% and 1.5%. The rate of infections after PRK seems to be higher than that after LASIK. Staphylococci, streptococci, and mycobacteria are the common etiological organisms. About 50–60% of patients present within the first week of surgery. Of the non-infectious keratitis, diffuse lamellar keratitis (DLK) is the most common with reported rates between 0.4% and 4.38%. The incidence of DLK seems to be higher with femtosecond LASIK than with microkeratome LASIK. A lot of stress is laid on prevention of this complication through proper case selection, asepsis, and use of improved protocols. Once keratitis develops, the right approach can help resolve this condition quickly. In cases of suspected microbial keratitis, laboratory identification of the organism is important. Most lesions resolve with medical management alone. Interface irrigation, flap amputation, collagen cross-linking and therapeutic penetrating keratoplasty (TPK) are reserved for severe/non-resolving cases. About 50–75% of all infectious keratitis cases post LRS resolve with a final vision of 20/40 or greater. Improved awareness, early diagnosis, and appropriate intervention can help limit the damage to cornea and preserve vision.

Traumatic laser in situ keratomileusis flap dislocation with epithelial ingrowth, Propionibacterium acnes infection, and diffuse lamellar keratitis: A case report

RATIONALE

Traumatic flap dislocation might occur anytime after laser in situ keratomileusis (LASIK), but it is rarely concomitantly complicated with epithelial ingrowth, infectious keratitis, and diffuse lamellar keratitis altogether. Here we report a case of traumatic LASIK flap inversion with epithelial ingrowth, Propionibacterium acnes infection, and diffuse lamellar keratitis.

PATIENT CONCERNS

A 42-year-old man receiving bilateral LASIK surgery 10 years ago complained of right eye pain for 6 days after twig injury. Temporal flap inversion with epithelial ingrowth and dense infiltration at the interface were noted.

DIAGNOSES

Traumatic LASIK flap inversion with epithelial ingrowth, Propionibacterium acnes infection and diffuse lamellar keratitis.

INTERVENTIONS

Removal of corneal epithelium around the flap inversion site, flap lifting, scraping of epithelial ingrowth, removal of the dense infiltrate, alcohol soaking, interface irrigation with antibiotics, and flap reposition were performed. Diffuse lamellar keratitis was noted postoperatively. Culture of the infiltrate revealed P acnes. The infiltrate subsided and the cornea cleared up under topical antibiotics and steroid.

OUTCOMES

The visual acuity returned to 20/20. No recurrent epithelial ingrowth or infiltrate was noted during the follow-up.

LESSONS

This is the first report of Propionibacterium acnes keratitis after traumatic flap inversion. Although epithelial ingrowth, infectious keratitis, and diffuse lamellar keratitis all developed after the flap inversion, early recognition and proper intervention lead to a good result without sequels.

Transient extremely shallow anterior chamber caused by ciliochoroidal detachment in a patient with Mycobacterium chelonae keratitis

Purpose

To report a case of Mycobacterium chelonae keratitis that resulted in a transient reduction of anterior chamber depth.

Observations

A 46-year-old man with keratoconus and reduced visual acuity (20/286) in his left eye presented with ciliary injection 16 months after femtosecond laser-assisted penetrating keratoplasty (PK). A slit-lamp examination showed a corneal ulcer with infiltrates and edema in both the host and graft between the 3 o'clock and 6 o'clock positions. Microbiologic tests confirmed the presence of M. chelonae. Topical arbekacin and moxifloxacin, erythromycin/colistin ointment, and oral clarithromycin were prescribed. We monitored anterior chamber depth by anterior segment optical coherence tomography (AS-OCT) throughout the recovery period. The anterior chamber depth was normal before treatment, with an intraocular pressure (IOP) of 7 mmHg. Although ciliary injection and infiltrates were gradually resolved, slit-lamp examination and AS-OCT revealed an extreme reduction of anterior chamber depth without corneal perforation, 1 month after beginning treatment. The IOP was 5 mmHg, and ciliochoroidal detachment (CCD) was present. The anterior chamber increased with the resolution of CCD and keratitis. Although hypotony continued despite the resolution of CCD and keratitis, the IOP eventually recovered to ≥10 mmHg at 1 month after remission. Onset and resolution of transient reduction of anterior chamber depth presumably occurred by anterior rotation and recovery of the ciliary body, respectively. Subsequent PK triple surgery enabled visual recovery to 20/100.

Conclusions and importance

severe anterior segment inflammation due to infectious keratitis may cause CCD and subsequent reduction of anterior chamber depth due to anterior rotation. AS-OCT is a non-invasive and efficient tool for the evaluation of iridociliary structure and the anterior chamber in patients with infectious keratitis.

Identification of the Infection Source of an Outbreak of Mycobacterium Chelonae Keratitis After Laser in Situ Keratomileusis

PURPOSE

Nontuberculous mycobacteria keratitis is a rare but challenging complication of laser in situ keratomileusis (LASIK). This study was conducted to determine the source(s) of infection in a cluster of cases of keratitis after LASIK and to describe this outbreak and patients' outcomes.

METHODS

In this retrospective, case series, single-center study, 86 patients were included who underwent LASIK or photorefractive keratectomy between December 2011 and February 2012. Corneal scrapes from the affected eyes, samples of tap and distilled water, water from the reservoir of the distilling equipment, steamer, and autoclave cassette; antiseptic and anesthetic solutions and surgical instrument imprints were cultivated in liquid and on solid media. Gram-negative bacteria and yeasts were identified using automated systems and mycobacteria by polymerase chain reaction-restriction enzyme analysis of the hsp65 gene (PRA-hsp65) and DNA sequencing. Mycobacterial isolates were typed by pulsed-field gel electrophoresis. The cases and outcomes are described. The main outcome measure was identification of the source(s) of the mycobacterial infections.

RESULTS

Eight (15 eyes) of 86 patients (172 eyes) who underwent LASIK developed infections postoperatively; no patients who underwent photorefractive keratectomy developed infections. Mycobacterium chelonae was isolated from 4 eyes. The distilled water collected in the surgical facility contained the same M. chelonae strain isolated from the patients' eyes. Different gram-negative bacteria and yeasts were isolated from samples collected at the clinic but not from the patients' eyes.

CONCLUSIONS

Tap water distilled locally in surgical facilities may be a source of infection after ocular surgery and its use should be avoided.

Bilateral Mycobacterium chelonae Keratitis after Phacoemulsification Cataract Surgery

The purpose of this manuscript is to report the case of an 81-year-old patient who presented with bilateral keratitis after phacoemulsification surgery. Cultures came back positive for Mycobacterium chelonae. Despite aggressive topical and systemic antimicrobial treatment, the patient developed a corneal perforation in both eyes, treated with corneal glue in the right eye and corneoscleral patch in the left eye. After two years of follow-up, patient was free of infection in the right eye with visual acuity of 20/200 and the left eye progressed to phthisis bulbi. We present an unusual case of bilateral Mycobacterium chelonae keratitis associated with phacoemulsification cataract surgery. This case represents the importance of making clinicians aware of this devastating infection and highlights the need for better management to improve outcomes.

Delayed onset Mycobacterium intracellulare keratitis after laser in situ keratomileusis: A case report and literature review

RATIONALE

Infectious keratitis is a relatively uncommon but potentially sight-threatening complication of laser in situ keratomileusis (LASIK). Mycobacterial keratitis is usually regarded as late onset keratitis among post-LASIK keratitis. There has been no documented case of Mycobacterium intracellulare post-LASIK keratitis of a long-latent period.

PATIENT CONCERNS

A 36-year-old man was referred to our out-patient clinic, for persistent corneal epithelial defect with intrastromal infiltration. He had undergone uneventful bilateral LASIK procedure 4 years before. He complained decreased vision, accompanied by ocular pain, photophobia, and redness in his left eye for 7 months.

DIAGNOSIS

Lamellar keratectomy was taken using femtosecond laser. Bacterial culture with sequenced bacterial 16s ribosomal DNA confirmed the organism to be M intracellulare.

INTERVENTIONS

After 3 months of administration of topical clarithromycin, amikacin, and moxifloxacin, the corneal epithelial defect was resolved and the infiltration was much improved. However, newly developed diffuse haziness with surrounding granular infiltration in the central cornea was noted. Drug toxicity was suspected and topical moxifloxacin was discontinued, resulting in resolution of the diffuse haze with infiltration.

OUTCOME

The patient was followed up regularly without medication thereafter and recurrence was not found for 7 years.

LESSONS

This case presents the first case of M intracellulare keratitis after LASIK. LASIK surgeons should aware that post-LASIK keratitis can develop long after the operation and careful suspicion of infectious disease with meticulous diagnostic test is needed.

A Multicenter Retrospective Survey of Refractive Surgery in 78,248 Eyes

PURPOSE

To retrospectively evaluate the current practice, trends, and outcomes of refractive surgery in Japan.

METHODS

This multicenter survey comprised 78,248 eyes of 39,727 consecutive patients who underwent refractive surgery at 45 major institutions in Japan. The corresponding ophthalmologists responded to a selfadministered questionnaire. The authors especially evaluated the safety, efficacy, predictability, stability, and adverse events of LASIK and phakic intraocular lens (IOL) implantation 3 months postoperatively.

RESULTS

The most common refractive surgery was LASIK (90.9%), followed by corneal inlay (5.0%), posterior chamber phakic IOL implantation (1.3%), laser-assisted subepithelial keratomileusis (1.0%), refractive lens exchange (0.9%), photorefractive keratectomy (0.3%), and refractive lenticule extraction (0.2%). For subgroup analysis, 69,987 eyes (99.5%) and 67,512 eyes (95.9%) achieved corrected and uncorrected distance visual acuity of 20/20 or better, respectively, after LASIK, and 935 eyes (98.8%) and 890 eyes (94.1%), respectively, after phakic IOL implantation. There were 69,176 eyes (98.3%) and 908 eyes (96.0%) within ±1.00 diopter (D) of the attempted correction after LASIK and phakic IOL implantation, respectively. There were 1,926 eyes (2.7%) and 1 eye (0.1%) with changes in refraction of 1.00 D or less from 1 week to 3 months after LASIK and phakic IOL implantation, respectively. No vision-threatening complications occurred in any case.

CONCLUSIONS

According to this survey, LASIK remains the most prevalent surgical technique in Japan. Both LASIK and phakic IOL implantation offered good safety and efficacy outcomes, yielding predictable and stable results. [J Refract Surg. 2017;33(9):598-602.].

Discovery of novel antimycobacterial drug therapy in biofilm of pathogenic nontuberculous mycobacterial keratitis

PURPOSE

The potential of slow-growing mycobacteria to form biofilms in human tissues contributes to the problem of establishing an effective treatment strategy. The purpose of this study was to examine new antibiotic strategies to enhance current treatment options for these infections.

METHODS

Sensitivities of Mycobacterium fortuitum ATCC 49404 and Mycobacterium chelonae ATCC 35752 were evaluated for different antimicrobials singly and in combination using broth microdilution and FICI (Fractional Inhibitory Concentration Index) synergy screening. Anti-biofilm effects were evaluated in an 8-well chamber slide biofilm model. The efficacy of a new treatment strategy was validated using the novel neutropenic mouse keratitis model and monitored by slit-lamp microscopy, confocal microscopy, and colony forming unit measurements.

RESULTS

We reported the very first evidence that these organisms develop corneal biofilms by the accumulation of extracellular DNA (eDNA) and the presence of microcolonies using a novel mycobacterial neutropenic mouse keratitis model. The combination of amikacin and gatifloxacin or besifloxacin was more effective than the current gold-standard drug, amikacin, and we developed a novel treatment strategy (amikacin + gatifloxacin + DNase), the destruction of biofilm matrix component, eDNA, which increased the efficacy of the new antibiotic combination for treating mycobacterial infection in in vitro (P = 0.002) and in vivo (P = 0.001) compared to its respective control.

CONCLUSION

Biofilms have a role in mycobacterial keratitis leading to poor treatment outcomes in clinical practice and the use of combination therapy (amikacin + gatifloxacin + DNase) could be a useful new treatment option.

An unusual case of spontaneous Mycobacterium chelonae corneal ulcer in a healthy middle-aged adult

Background

To report a rare presentation of culture-positive Mycobacterium chelonae corneal ulcer and its management.

Findings

We report a rare case of a patient with a history of chronic pain and blurriness of vision. Examination revealed a chronic nonhealing paracentral corneal ulcer inferiorly at the 5–7 o’clock meridian with anterior chamber reaction unresponsive to routine antibiotic and antifungal medications with Mantoux test positivity in a middle-aged nondiabetic patient with no prior history of trauma, ocular surgery, and contact lens usage. Ziehl–Neelsen staining of the nonhealing ulcer revealed acid-fast bacilli typical of M. chelonae, with subsequent culture positivity in Löwenstein–Jensen medium. Subsequent treatment with topical fortified amikacin and tobramycin resulted in rapid healing of the corneal ulcer.

Conclusion

M. chelonae presenting as a chronic nonhealing corneal ulcer spontaneously occurring in a healthy adult with no predisposing factor draws attention towards the need to have a good index of suspicion by performing a Ziehl–Neelsen stain and culture, and subsequent successful management with topical fortified amikacin and tobramycin.

A cluster of Mycobacterium massiliense keratitis in foundry workers

Three consecutive workers from the same foundry had Mycobacterium massiliense keratitis. The strains isolated from each patient were identical. This is the first report of a non-surgery-related outbreak of non-tuberculous mycobacterial ocular infection. An investigation revealed that injured cornea with exposure to aerosolized non-tuberculous mycobacteria might account for this outbreak.

An Unusual Case of Nonhealing Granulomatous Keratitis Caused by Mycobacterium chelonae in a Healthy Middle Aged Adult

Purpose. To report a rare presentation of culture positive Mycobacterium chelonae (M. chelonae) corneal ulcer and its management. Case Report. We report a rare case with history of chronic pain and blurriness of vision. Examination revealed chronic nonhealing paracentral corneal ulcer inferiorly at 5 to 7 o'clock meridian with anterior chamber cells 1+ unresponsive to routine antibiotic and antifungal medications with Mantoux test (MT) positivity in a middle aged nondiabetic patient with no prior obvious history of trauma, ocular surgery, and contact lens usage. Discussion. Ziehl Neelsen (ZN) staining in nonhealing ulcer revealed acid fast bacilli typical of M. chelonae with subsequent culture positivity in Lowenstein Jensen (LJ) medium. Subsequent treatment with topical fortified amikacin and tobramycin resulted in rapid healing of corneal ulcer. Conclusion. M. chelonae presenting as a chronic nonhealing corneal ulcer spontaneously occurring in a healthy young adult with no predisposing factor draws the need to have a good index of suspicion by performing ZN stain and culture and its subsequent successful management with topical fortified amikacin and tobramycin.

Nontuberculous Mycobacterial Ocular Infections: A Systematic Review of the Literature

Nontuberculous or atypical mycobacterial ocular infections have been increasing in prevalence over the past few decades. They are known to cause periocular, adnexal, ocular surface and intraocular infections and are often recalcitrant to medical therapy. These infections can potentially cause detrimental outcomes, in part due to a delay in diagnosis. We review 174 case reports and series on nontuberculous mycobacterial (NTM) ocular infections and discuss etiology, microbiology, risk factors, diagnosis, clinical presentation, and treatment of these infections. History of interventions, trauma, foreign bodies, implants, contact lenses, and steroids are linked to NTM ocular infections. Steroid use may prolong the duration of the infection and cause poorer visual outcomes. Early diagnosis and initiation of treatment with multiple antibiotics are necessary to achieve the best visual outcome.

Long-term observation and evaluation of femtosecond laser-assisted thin-flap laser in situ keratomileusis in eyes with thin corneas but normal topography

PURPOSE

To evaluate the long-term outcomes of thin-flap laser in situ keratomileusis (LASIK) in eyes with thin corneas (central corneal thickness [CCT] <500 μm) but normal topography.

SETTING

Private center, Tokyo, Japan.

DESIGN

Retrospective randomized comparative study.

METHOD

The efficacy, safety, predictability, and topography of LASIK were evaluated in eyes with a CCT of less than 500 μm but with normal topography (thin-cornea group) to 6 years postoperatively. The LASIK outcomes in the thin-cornea group were compared with those in eyes with a CCT of 500 μm or greater (control group). Analysis was performed to determine whether there were differences between the groups at the last checkup 3 to 4 years postoperatively.

RESULTS

In the thin-cornea group (291 eyes; 146 patients), no significant differences were observed in LASIK outcomes when eyes were subdivided by the time of final checkup (3, 4, and ≥ 5 years). There was a significant difference in visual and refractive outcomes between 3 months postoperatively and the last checkup in the thin-cornea group and the control group (371 eyes; 193 patients). No significant difference in visual, refractive, or topography outcomes was observed between the 2 groups at the last checkup.

CONCLUSIONS

Laser in situ keratomileusis in eyes with thin corneas was as safe and effective as and showed similar long-term stability in eyes with a CCT of 500 μm or greater. No eye in either group had a postoperative complication.

FINANCIAL DISCLOSURE

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

Diseases caused by nontuberculous mycobacteria in Asia

 The isolation rate of nontuberculous mycobacteria (NTM) species and the prevalence of NTM-associated diseases are on the rise in Asian, as well as in Western countries; however, the species distribution of NTM isolates and the types of diseases caused by NTM species vary from region to region. In this review, we present an update on the epidemiology of NTM in Asia. We demonstrate that the distribution of NTM species varies within Asia and differs from that in North America and Europe. In addition, the clinical manifestations of NTM diseases include respiratory tract infections, disseminated infections, skin and soft tissue infections, lymphadenitis, empyema, ocular infections, CNS infections and genitourinary infections. Finally, the rate of adaptive resistance of anti-NTM antimicrobial agents remains high and may be associated with a poor outcome for patients with NTM diseases.

Non-tuberculous mycobacterial keratitis

Non-tuberculous mycobacteria are environmental, opportunistic pathogens that are increasingly being recognized as important causes of many human diseases. Among them, rapidly growing mycobacteria are the most notorious organisms causing infectious keratitis. Non-tuberculous mycobacterial (NTM) keratitis commonly occurs after trauma or refractive surgery, and can masquerade as fungal, herpetic or amoebic keratitis. Therefore, the diagnosis is often delayed. Prolonged medical treatment and judicious surgical debridement are required in order to eradicate the pathogens. Combination therapy with aminoglycosides, macrolides and fluoroquinolones improves the prognosis and decreases the occurrence of drug resistance. However, regardless of the development of new diagnostic techniques and antimicrobials, NTM keratitis remains a clinical challenge for most ophthalmologists. In this article, we provide a concise introduction to the epidemiological features and clinical characteristics of NTM keratitis, and the modern diagnostic tools used for it. We also summarize the current concepts of prevention and treatment for this potentially devastating condition.

LASIK interface complications: etiology, management, and outcomes

PURPOSE

To describe the etiology, diagnosis, clinical course, and management of LASIK interface complications.

METHODS

Literature review.

RESULTS

Primary interface complications include infectious keratitis, diffuse lamellar keratitis, central toxic keratopathy, pressure-induced stromal keratopathy (PISK), and epithelial ingrowth. Infectious keratitis is most commonly caused by Methicillin-resistant Staphylococcus aureus (early onset) or atypical Mycobacterium (late onset) postoperatively, and immediate treatment includes flap lift and irrigation, cultures, and initiation of broad-spectrum topical antibiotics, with possible flap amputation for recalcitrant cases. Diffuse lamellar keratitis is a white blood cell infiltrate that appears within the first 5 days postoperatively and is acutely responsive to aggressive topical and oral steroid use in the early stages, but may require flap lift and irrigation to prevent flap necrosis if inflammation worsens. In contrast, PISK is caused by acute steroid response and resolves only with cessation of steroid use and intraocular pressure lowering. Without appropriate therapy PISK can result in severe optic nerve damage. Central toxic keratopathy mimics stage 4 diffuse lamellar keratitis, but occurs early in the postoperative period and is noninflammatory. Observation is the only effective treatment, and flap lift is usually not warranted. Epithelial ingrowth is easily distinguishable from other interface complications and may be self-limited or require flap lift to treat irregular astigmatism and prevent flap melt.

CONCLUSIONS

Differentiating between interface entities is critical to rapid appropriate diagnosis, treatment, and ultimate visual outcome. Although initial presentations may overlap significantly, the conditions can be readily distinguished with close follow-up, and most complications can resolve without significant visual sequelae when treated appropriately.