Infectious keratitis after photorefractive keratectomy in a comanaged setting

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.

Post photorefractive keratectomy (PRK) infectious keratitis; six-year experience of a tertiary eye hospital

BACKGROUND/OBJECTIVES

As an essential development in the new century, surface ablation procedures have attracted increasing attention. There exists a concern regarding the risk of infectious keratitis. Hence, we aimed to investigate the rate and predisposing factors of infectious keratitis after photorefractive keratectomy (PRK).

SUBJECTS/METHODS

This retrospective study was designed in two phases. First, the rate of post-PRK keratitis of Farabi Eye Hospital was investigated. In other words, the targeted population was the patients who developed keratitis after performing procedure at Farabi Eye Hospital. In the second phase, all the patients with the diagnosis of post-PRK keratitis were studied regardless of the centre where surgery was performed. Patients with the diagnosis of infectious keratitis between 2014 and 2020 were enrolled and following information was analyzed: demographics, presentation time after surgery, perioperative medications, culture results, risk factors, medical treatment, complications, and final visual acuity.

RESULTS

The total number of PRK procedures in our centre was 24,986 (13,253 patients), in which 6 eyes of 5 patients developed keratitis. Beside these 5 patients, 24 referred patients (24 eyes) from the other centres were enrolled. Finally, a total number of 29 patients (30 eyes) were included. Our analysis revealed that manipulation of contact lens, dry eye, and blepharitis were the essential predisposing factors for keratitis development.

CONCLUSION

The overall post-PRK keratitis occurrence rate of our study was 0.02%. Our observation highlighted the importance of preoperative examination and treatment of the lids and dry eye disease.

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.

Bilateral methicillin-resistant Staphylococcus aureus keratitis after photorefractive keratectomy

A 52-year-old woman with a history of liver transplantation developed bilateral corneal infiltrates 1 week after uneventful photorefractive keratectomy (PRK). Cultures grew methicillin-resistant Staphylococcus aureus (MRSA), resistant to fluoroquinolone antibiotics. The infections responded to topical vancomycin and resolved bilaterally over 3 weeks. Three months postoperatively, the uncorrected visual acuity (UCVA) was 20/20 in the right eye and 20/25 in the left eye; the best spectacle-corrected visual acuity (BSCVA) was 20/20 in both eyes. During the course of treatment, the patient reported chronic intermittent prophylactic use of oral ciprofloxacin. While fluoroquinolones typically provide excellent postoperative coverage, Staphylococcus organisms have a growing antibiotic resistance to fluoroquinolones, and MRSA may become a more prevalent organism in corneal infections. Chronic subtherapeutic fluoroquinolone use can increase the mutational resistance of Staphylococcus to fluoroquinolone and methicillin. The patient's frequent hospital visits placed her at high risk for MRSA colonization. This case represents the fifth reported case of MRSA keratitis after PRK.

Bilateral Bacterial Keratitis in Three Patients Following Photorefractive Keratectomy

PURPOSE

To report clinical manifestations and the bacteriologic profiles of three patients with bilateral bacterial keratitis following photorefractive keratectomy (PRK).

METHODS

Photorefractive keratectomy was performed for mild to moderate myopia or compound myopic astigmatism. Bandage contact lenses were fitted at the conclusion of each surgery. Bilateral infectious keratitis was diagnosed within 3 days after surgery. Smear and culture were obtained in all three cases. Patients were treated with topical fortified antibiotics (cefazolin and gentamicin).

RESULTS

All patients presented with severe bilateral ocular pain, photophobia, purulent discharge, and dense corneal infiltration. Causative organisms were Staphylococcus aureus (n = 2) and Streptococcus pneumoniae (n = 1). Ulcers were controlled with aggressive medical therapy in five eyes; however, tectonic penetrating keratoplasty was required in one eye.

CONCLUSIONS

Uncontrolled blepharitis and bandage contact lens use appears to play a role in the development of bacterial keratitis after PRK. Avoidance of simultaneous bilateral surgery in patients with risk factors for bacterial keratitis, preoperative control of blepharitis, and good contact lens hygiene is suggested.

Corneal Infiltrates After Excimer Laser Photorefractive Keratectomy and LASIK

PURPOSE

To determine the frequency and clinical characteristics of corneal infiltrates after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) and to evaluate the efficacy of treatment.

METHODS

We retrospectively reviewed the records of 8508 eyes treated with PRK or LASIK in a university-based clinic for the correction of refractive errors for 60 days postoperatively.

RESULTS

Corneal infiltrates were observed in 35 (0.8%) of 4492 PRK-operated eyes and in 4 (0.1%) of 4016 LASIK-operated eyes. The mean time of diagnosis was 5.46 days. Among the 39 eyes with infiltrates, 10 (9 PRK, 1 LASIK) had culture-verified infectious keratitis. Coagulase-negative Staphylococcus was the most frequently isolated bacterium (50%), followed by S aureus (20%), Corynebacterium xerosis (10%), Streptococcus viridans (10%), and an unidentified gram-positive coccus (10%). Final visual acuity of > or = 20/30, without correction, was achieved in 79.5% of the 39 eyes.

CONCLUSIONS

Corneal infiltrates occurred in 0.8% of PRK eyes and 0.1% of LASIK eyes. Bacterial smears were positive for several eyes. In all cases, prompt treatment was responsible for good visual outcome.

Bilateral methicillin-resistant staphylococcus aureus keratitis in a medical resident following an uneventful bilateral photorefractive keratectomy

PURPOSE

To present a case of bilateral methicillin-resistant Staphylococcus aureus (MRSA) keratitis after photorefractive keratectomy (PRK).

METHODS

Retrospective chart review. RESULTS A 26-year-old female internal medicine resident underwent an uneventful bilateral PRK. After the procedure, the patient was fit with a bandage contact lens and was prescribed tobramycin 0.3%, fluorometholone 0.1%, and diclofenac sodium 0.1% four times per day. Postoperatively, corneal ulcers were noted in each eye, and the patient was referred for a consultation. Gram stain showed gram-positive cocci. The patient immediately started using vancomycin, 35 mg/mL every half hour, and ofloxacin 0.3% every hour around the clock. Forty-eight hours later, corneal and lid cultures were positive for MRSA. Three months after the infection, there was approximately 40% corneal thinning in the right eye and 10% thinning in the area of the corneal ulceration of the left eye. The patient is awaiting corneal transplantation of the right eye.

CONCLUSIONS

To our knowledge, this represents the first reported case of bilateral MRSA keratitis after PRK. Methicillin-resistant S. aureus is a potentially serious infectious agent after PRK and may be associated with exposure to a hospital setting. For patients who have had extensive exposure to a hospital environment and are undergoing ocular surgery, we recommend prophylaxis against MRSA. To treat a possible MRSA keratitis, we suggest starting a fourth-generation topical fluoroquinolone every 30 minutes, alternating it with vancomycin 50 mg/mL every 30 minutes, and discontinuing steroid use. A high degree of suspicion coupled with rapid and appropriate treatment may result in improved visual recovery.

Fungal Keratitis After Photorefractive Keratectomy: Delayed Diagnosis and Treatment in a Co-managed Setting

PURPOSE

To report a case of fungal keratitis following photorefractive keratectomy (PRK) in a co-managed setting.

METHODS

A 35-year-old man with a preoperative refraction of -13.00 +3.75 x 18 degrees OD, and -12.50 +2.50 x 70 degrees OS underwent bilateral simultaneous PRK. On postoperative day 16, the patient presented with complaints of decreased vision and foreign body sensation. Examination by the co-managing optometrist revealed a visual acuity of 20/200, and a central corneal ulcer. Cultures were not taken and the patient was started on topical ofloxacin and prednisolone acetate 1% every hour. The patient was instructed to follow-up with another optometrist closer to the patient's home. Tobradex (tobramycin 0.3% combined with dexamethasone 0.1%) was added to the treatment regimen on postoperative day 23, but the ulcer continued to worsen. The patient was then referred to an ophthalmologist where corneal cultures were performed, but came back negative.

RESULTS

Despite treatment with fortified antibiotics, the ulcer perforated, requiring penetrating keratoplasty. Bacterial and fungal cultures were negative. Pathology examination of the specimen revealed fungal hyphae.

CONCLUSIONS

Although co-management of refractive patients may be a common practice, it is not without risks. In this case, delayed diagnosis and inappropriate treatment resulted in a poor final outcome.

Infectious keratitis after photorefractive keratectomy

PURPOSE

To elucidate risk factors, microbial culture results, and visual outcomes for infectious keratitis after photorefractive keratectomy (PRK).

DESIGN

Multicenter, retrospective chart review, case report, and literature review.

METHODS

The records of 12 patients with infectious keratitis after PRK were reviewed.

MAIN OUTCOME MEASURES

Causative organism, response to medical treatment, and visual outcome.

RESULTS

Infectious keratitis developed in 13 eyes of 12 patients after PRK. Organisms cultured were Staphylococcus aureus (n = 5), including a bilateral case of methicillin-resistant Staphylococcus aureus; Staphylococcus epidermidis (n = 4); Streptococcus pneumoniae (n = 3); and Streptococcus viridans (n = 1). Four patients manipulated their contact lenses, and 2 patients were exposed to nosocomial organisms while working in a hospital environment. Prophylactic antibiotics used were tobramycin (nine cases), polymyxin B-trimethoprim (three cases), and ciprofloxacin (one case). Final best spectacle-corrected visual acuity ranged from 20/20 to 20/100.

CONCLUSIONS

Infectious corneal ulceration is a serious potential complication of PRK. Gram-positive organisms are the most common pathogens. Antibiotic prophylaxis should be broad spectrum and should include gram-positive coverage.

Acanthamoeba keratitis after photorefractive keratectomy

A 37-year-old women developed severe suppurative keratitis immediately after having photorefractive keratectomy in her left eye. The keratitis was unresponsive to intensive topical antibiotic agents and topical and systemic steroids. Although the differential diagnosis included nonmicrobial and fungal keratitis, the clinical course and confocal microscopy suggested, and subsequent histopathologic examination confirmed, a diagnosis of Acanthamoeba keratitis. The amebic contamination probably resulted from exposure of the deepithelialized cornea to contaminated freshwater in a northern Wisconsin marsh. This case emphasizes the importance of encouraging patients with epithelial defects and bandage soft contact lenses to avoid exposure to contaminated freshwater until reepithelialization is complete.

Perioperative Microbiologic Profile of the Conjunctiva in Photorefractive Keratectomy

PURPOSE

Therapeutic soft contact lenses are used commonly as an adjunctive treatment after photorefractive keratectomy (PRK) to decrease postoperative pain caused by the movement of lids over the corneal epithelial defect and to facilitate epithelial healing. We assessed the microbiological profile of the conjunctiva of patients undergoing PRK for myopia, before and after the concurrent use of a therapeutic soft contact lens, and compared the effect on ocular bacterial colonization of prophylactic administration of topical tobramycin 0.3% versus ofloxacin 0.3%.

METHODS

Forty-three consecutive eyes from 37 patients underwent PRK for myopia or myopic astigmatism. Eyes were assigned randomly to prophylactic antibacterial treatment with either topical ofloxacin 0.3% or tobramycin 0.3%, applied prior to surgery and three times daily after surgery until therapeutic soft contact lens removal. Material from the conjunctival sac was obtained for bacteriologic cultures prior to surgery. Clinical evaluation of all eyes was conducted prospectively. Three days after PRK, the therapeutic soft contact lenses were removed and cultured. Cultures from the conjunctival sac were then repeated.

RESULTS

No statistically significant differences were observed in culture positivity between the two groups of eyes, in spite of some positive preoperative and postoperative cultures. Only one out of 43 eyes (assigned to the ofloxacin group) developed a peripheral corneal infiltrate. The corneal infiltrate healed completely without sequelae using antibiotic and corticosteroid therapy.

CONCLUSIONS

The use of therapeutic soft contact lenses after PRK with either topical tobramycin 0.3% or ofloxacin 0.3% were well tolerated. However, perioperative positive conjunctival cultures were relatively frequent and prophylactic antibiotics should be used in the setting of an epithelial defect and therapeutic soft contact lens following PRK.