Infectious and noninfectious keratitis after laser in situ keratomileusis

[Infectious keratitis in 266,191 laser in situ keratomileusis]

OBJECTIVE

To study the incidence of infectious keratitis (IK) after laser-assisted in situ keratomileusis (LASIK), along with its diagnosis, therapeutic action taken, its management and the results.

MATERIAL AND METHOD

We carried out a retrospective study of 262,191 eyes intervened consecutively with LASIK, in our 20 centres, during the period from September 2002 and December 2009. All the cases susceptible to being diagnosed with IK, either clinically or due to the biological findings were analysed.

RESULTS

A total of 82 cases were found with infectious keratitis, which assumed an incidence of 0.031%. Distributions are presented by gender, mean age of the patients, mean days since the surgery, the clinical signs and symptoms, predisposing factors, therapeutic action, complications, details of the causal germ, and the loss of lines of vision.

CONCLUSIONS

Infectious keratitis after LASIK is a rare complication. The early diagnosis and management of the process are determining factors when establishing the prognosis. In our series all the cases were resolved without causing any other serious complications.

Infectious keratitis in 204 586 LASIK procedures

PURPOSE

To investigate the incidence, culture results, risk factors, and visual outcomes of infectious keratitis after LASIK, and examine treatment strategies.

DESIGN

Retrospective study.

PARTICIPANTS

We included 107 613 patients who underwent LASIK at Clínica Baviera (Instituto Oftalmológico Europeo, Spain) from September 2002 to May 2008.

METHODS

The medical records of post-LASIK patients (204 586 eyes) were reviewed to identify cases of infectious keratitis. Incidence, risk factors, clinical course, days to diagnosis, medical and surgical treatment, and final visual outcomes were recorded.

MAIN OUTCOME MEASURES

Incidence of post-LASIK infectious keratitis, culture results, response to treatment, and visual outcome.

RESULTS

Post-LASIK infectious keratitis was diagnosed in 72 eyes from 63 patients. Onset of infection was early (within 7 days after surgery) in 62.5% of cases. Cultures were positive in 21 of 54 cases in which samples were taken. The most frequently isolated microorganism was Staphylococcus epidermidis (9 cases). Immediate flap lifting and irrigation with antibiotics was performed in 54 eyes; late flap lifting was subsequently required in 10 out of 18 cases initially treated with topical antibiotics alone. One case required flap amputation owing to flap necrosis. Final best spectacle-corrected visual acuity (BSCVA) was >or=20/20 in 38 cases (52.7%) and >or=20/40 in 67 cases (93.05%); final BSCVA was <20/40 in 5 cases (6.94%).

CONCLUSIONS

The incidence of post-LASIK infectious keratitis was 0.035% per procedure. Infectious keratitis after LASIK is a potentially vision-threatening complication. The appearance of infections in asymptomatic patients highlights the need for a proper schedule of follow-up appointments. Prompt and aggressive management of this LASIK complication with early flap lifting, scraping, culture, and irrigation with antibiotics is strongly recommended. Proper management can result in preserving useful vision.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Reactivated herpetic keratitis following laser in situ keratomileusis

A 40-year-old woman presented with an unusual form of corneal herpetic reactivation 5 weeks after laser in situ keratomileusis. The cornea showed diffuse edema and a stromal ring infiltrate (disciform in appearance). Oral antiviral and topical steroids in tapered dosages were administered. The infiltrate disappeared within 6 weeks. Progressive improvement was also seen in all the parameters on Pentacam scans, including the pachymetry, keratometry readings, and elevation on the anterior float. Herpetic reactivation may occur in many forms after excimer laser ablation. Timely diagnosis and management is crucial to maintain good structural and visual outcomes. Pentacam analysis may serve as a useful adjunct in following the progression of herpetic reactivation cases.

Outbreak of Nocardia keratitis after photorefractive keratectomy: clinical, microbiological, histopathological, and confocal scan study

Nocardia keratitis occurred in 4 eyes of 3 patients (2 women and 1 man) who had photorefractive keratectomy (PRK) by the same surgeon at the same center. Two eyes of the first 2 patients required lamellar keratectomy to debulk the involved stroma and obtain specimens for microbiological and histopathological evaluation. Light microscopic examination disclosed gram-positive and acid-fast filaments of Nocardia that were confirmed by the microbiological results. Diagnosis of Nocardia keratitis in the third case was not as challenging as in the first 2 cases because of a high index of suspicion. Confocal scans of all cases disclosed hyperreflective and slender, fibril-like structures in the corneal stroma. All eyes responded favorably to topical amikacin and the infection resolved without recurrence. The most probable cause of the outbreak was inadequate attention to sterility during surgery.

Antibiotic susceptibility of conjunctival bacterial isolates from refractive surgery patients

PURPOSE

To determine the in vitro antibiotic susceptibility patterns of conjunctival bacterial flora isolated before surgery from patients undergoing refractive surgery.

DESIGN

In vitro laboratory investigation.

PARTICIPANTS

One hundred five eyes from 105 patients scheduled for refractive surgery at Balgensesang Ophthalmology Clinic between September 2005 and January 2006 were studied. Among 105 patients, 71 (67.6%) underwent LASIK using a femtosecond laser, 24 (22.9%) underwent LASIK using an automated microkeratome, 8 (7.6%) underwent LASEK, and 2 (1.9%) patients underwent phakic intraocular lens implantation.

METHODS

Preoperative conjunctival swab samples were inoculated directly in culture media at the bedside before topical anesthetic or antibiotic application. Blood agar, chocolate agar, thioglycolate broth, Sabouraud dextrose agar, and Ogawa media were used for bacterial, fungal, and mycobacterial cultures.

MAIN OUTCOME MEASURES

Minimum inhibitory concentrations (MICs) of ofloxacin (OFX), levofloxacin (LEV), gatifloxacin (GAT), moxifloxacin (MOX), gemifloxacin (GEM), and other commonly used antibiotics were determined using an E test.

RESULTS

From 105 patients, 73 (85%) coagulase-negative staphylococci (CNS), 2 (2.3%) Staphylococcus aureus, 1 (1.2%) Streptococcus pneumoniae, and 5 (4.8%) gram-negative bacilli were isolated. No fungi or mycobacteria were isolated. The MIC that would inhibit the growth of 90% of the tested bacterial isolates (MIC(90)) of OFX, LEV, GAT, MOX, and GEM for methicillin-susceptible CNS (n = 46) were 0.5 microg/ml, 0.19 microg/ml, 0.094 microg/ml, 0.047 microg/ml, and 0.023 microg/ml, respectively. The MIC(90) values for methicillin-resistant CNS (n = 27) were 32 microg/ml, 4 microg/ml, 1 microg/ml, 0.5 microg/ml, and 0.25 microg/ml, respectively (P<0.001).

CONCLUSIONS

The most effective against conjunctival bacteria isolated from refractive surgery patients were GEM, MOX, and GAT; however, resistance to earlier-generation fluoroquinolones (OFX and LEV) is increasing among methicillin-resistant CNS. It may be a therapeutic option to use newer fluoroquinolones in patients undergoing refractive eye surgery to reduce such infections as methicillin-resistant CNS.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

[A case of Scedosporium apiospermum keratitis confirmed by a molecular genetic method]

A 54-yr-old male, who was treated by chemotherapy for gastric cancer 15 months ago, presented to Yongdong Severance Hospital, Seoul, with complaints of pain in his right eye caused by a foreign body from the ground in the previous week. He had been treated with topical and oral antibacterial in addition to antifungal agents, but did not show significant clinical improvement. After a positive corneal culture with mold, topical amphotericin B was added to the initial regimen. The mold was identified as Scedosporium apiospermum by macroscopic and microscopic morphologies and the nucleotide sequences of a fungal PCR product showing 99% homology with those of S. apiospermum (EF151349). He recovered with good results at 25 days after corneal epithelial debridement. The early diagnosis of S. apiospermum keratitis is very important for proper treatment. It is recommended that molecular diagnostic methods such as fungal PCR and sequencing be done with conventional cultures whenever a fungal infection is suspected.

Two cases of methicillin-resistant Staphylococcus aureus keratitis after Epi-LASIK

BACKGROUND

We describe two severe cases of methicillin-resistant Staphylococcus aureus (MRSA) keratitis following Epi-LASIK surgery.

CASES

One patient was a 23-year-old man who underwent Epi-LASIK surgery in both eyes. He developed an infectious corneal ulcer in one eye 2 days after surgery and was referred to us 7 days post-surgery with corneal perforation, for which we performed therapeutic penetrating keratoplasty. The other patient was a 32-year-old man who developed infectious keratitis in one eye 4 days after bilateral Epi-LASIK and was referred to us 2 days later.

OBSERVATIONS

Microbial testing revealed MRSA infection as the cause of the keratitis in both patients which was successfully treated with vancomycin eyedrops.

CONCLUSION

Infectious keratitis after refractive surgery is uncommon; it is important to diagnose this condition, identify the causative agent, and initiate treatment with appropriate antibiotics as soon as possible.

Basic knowledge of refractive surgery: correction of refractive errors using modern surgical procedures

INTRODUCTION

Refractive ophthalmic surgery allows refractive errors to be corrected permanently in a safe, effective, and reliable way with few complications.

METHODS

Selective literature review with special reference to the guidelines of the German Commission for Refractive Surgery.

RESULTS

With a total of almost 18 million treatments performed to date, laser in-situ keratomileusis (LASIK) is the most commonly used refractive surgical procedure worldwide. Alternatives to LASIK include surface ablation procedures (PRK, LASEK, Epi-LASIK) and phakic intraocular lens implantation. If ocular accommodation is lost, removal of the crystalline lens and implantation of modern multifocal intraocular lenses (refractive lens exchange) provide an alternative means of correcting myopia, hyperopia and presbyopia.

DISCUSSION

The treatment effect is maximized and complications kept to a minimum if strict inclusion criteria are applied and a high technical standard maintained during the procedure.