Bilateral infectious keratitis after small-incision lenticule extraction

Impact of Latent Virus Infection in the Cornea on Corneal Healing after Small Incision Lenticule Extraction

The aim of the present study is to analyze the impact of cornea virus latent infection on corneal healing after small incision lenticule extraction (SMILE) and predict the positive rate of virus latent infection in corneal stroma. A total of 279 patients who underwent SMILE were included in this study. Fluorescence quantitative PCR was used to detect virus infection in the lenticules, which were taken from the corneal stroma during SMILE. Herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), Epstein-Barr virus (EBV), and cytomegalovirus (CMV) were detected. Postoperative visual acuity, spherical equivalent, intraocular pressure, corneal curvature (Kf and Ks), corneal transparency, and corneal staining were compared between the virus-positive group and the virus-negative group. The number of corneal stromal cells and inflammatory cells, corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), corneal total branch density (CTBD), and corneal nerve fiber width (CNFW) were evaluated using an in vivo confocal microscope. Out of 240 herpes simplex virus (HSV) tested samples, 11 (4.58%) were positive, among which 5 (2.08%) were HSV-1-positive and 6 (2.50%) were HSV-2-positive. None of the 91 CMV- and EBV-tested samples were positive. There was no statistical significance in the postoperative visual acuity, spherical equivalent, intraocular pressure, Kf and Ks, corneal transparency, corneal staining, the number of corneal stromal cells and inflammatory cells, CNFD, CNBD, CNFL, CTBD, and CNFW between the virus-positive and virus-negative groups (p > 0.05). In conclusion, there is a certain proportion of latent HSV infection in the myopia population. Femtosecond lasers are less likely to activate a latent infection of HSV in the cornea. The latent infection of HSV has no significant impact on corneal healing after SMILE.

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.

Bacterial Keratitis Following Small Incision Lenticule Extraction

Purpose

To describe the development of bacterial keratitis after small incision lenticule extraction in 5 patients and to explore its appropriate therapies.

Methods

We retrospectively summarized the clinical treatments of five patients with postoperative bacterial infection after small incision lenticule extraction, who were referred to our hospital from 2019 to 2021.

Results

Five male patients had undergone bilateral SMILE in the local hospital due to myopia aged from 18 to 26 years. The onset of keratitis during 1–3 days postoperatively and four of them were severe infection (2 bilateral, 2 unilateral). In five cases, 1 patient (1 eye) who was infected mild keratitis after SMILE was treated with only topical antibiotics; the others who respond poorly to topical antibiotics require surgical treatment, which 1 patient (1 eye) infected necrotic mass of the corneal cap was scraped and irrigated with antibiotic, and 3 patients (5 eyes) were treated by converting the cap to flap, curetting the necrotic tissue and irrigating with the antibiotic solution. In all patients, the duration from onset to resolution was 1–5 weeks. The final uncorrected visual acuity was above 20/32.

Conclusion

Owing to the upward popularity of refractive surgery, the incidence of keratitis after SMILE should not be ignored. Early diagnosis and timely treatment of post-SMILE keratitis are essential. For severe keratitis that fails to respond to topical antibiotics, the corneal cap should be opened as a flap.

Fungal keratitis after small incision lenticule extraction (SMILE): a case report and review of the literature

Purpose

To report a case of perforated fungal keratitis after small incision lenticule extraction (SMILE) treated with penetrating keratoplasty (PKP).

Methods

Case report and literature review.

Results

A 41-year-old woman presented with culture-proven unilateral fungal keratitis 4 days after uneventful SMILE. Her visual acuity was hand motion. The patient was treated with voriconazole irrigation (50 μm/0.1 ml) of the pocket and intrastromal voriconazole injection, in addition to systemic and topical antifungals. Despite aggressive management and decreased infiltration, the cornea was perforated and subsequently treated with PKP.

Conclusions

Infectious keratitis after SMILE is unusual. To our knowledge, this is the first report of perforated fungal keratitis post-SMILE. PKP eradicated the infection.

Combined Bacterial and Herpes Simplex Virus Keratitis following Small-Incision Lenticule Extraction for the Correction of Myopia

A 28-year-old male presented unilateral visual loss, intense ocular pain, redness and intraocular hypertension in his right eye 2 days after undergoing small-incision lenticule extraction (SMILE) in both eyes. Initial examination of the affected eye revealed the presence of white infiltrates within the corneal interface, as well as a central epithelial defect. The patient was diagnosed with infectious keratitis, posteriorly the eye was irrigated with balanced saline solution and treatment was initiated with hourly moxifloxacin 0.5%. Since this approach failed to resolve symptoms, a sample from the interface was obtained for PCR assay, which revealed the presence of herpes simplex virus DNA, confirming the cause of the infection. The patient was prescribed a regimen of oral acyclovir, topical ganciclovir and prednisolone. Clinical improvement following resolution of the epithelial defect was observed. Although rare, herpetic keratitis following SMILE is best managed via early diagnosis and initiation of appropriate anti-herpetic treatment.

Prevention of infection after corneal refractive surgery: a French survey

PURPOSE

To report the French refractive surgeons' real-life practices for preventing infection after corneal refractive surgery (photorefractive keratotomy [PRK], laser in situ keratomileusis [LASIK], and small-incision lenticule extraction).

SETTING

France.

DESIGN

Anonymous practice survey.

METHODS

The questionnaire was sent in a single email invitation to 400 declared refractive surgeons. The following information was recorded between December 2019 and April 2020, before the coronavirus pandemic: demographics data, preoperative evaluation and preparation of the patient, surgical management, immediate and postoperative protocol, and infections reported after corneal refractive surgery.

RESULTS

Eighty-three of 400 surgeons (20.75%) responded to the questionnaire; 55 (66.0%) performed more than 50 corneal refractive surgeries a year, and 25 (30.1%) performed more than 200 procedures a year. Thirty-six (43.4%) surgeons wore 3 protective items, 37 (44.6%) 2, 5 (6.0%) 1, and 5 (6.0%) zero. Seventy-seven (92.8%) surgeons used povidone-iodine for skin area disinfection and 54 (65%) for conjunctival fornix disinfection. The contact time of povidone-iodine was less than 3 minutes for 71 (85.0%) surgeons. Twenty surgeons (24.1%) reported at least 1 postrefractive surgery infection. Twenty percent of surgeons who wore sterile gloves for PRK reported postoperative infections compared with 62.5% for those who did not (P = .008). These figures were, respectively, 8.7% and 66.7% for the use of sterile gloves during LASIK (P = .002); 8.9% of surgeons who wore surgical masks for LASIK reported postoperative infections compared with 50.0% for those who did not (P = .01).

CONCLUSIONS

Practices are variable among French refractive surgeons. Wearing a surgical mask and sterile gloves during corneal refractive surgery appears to be advisable.

Management of infectious keratitis following uneventful small-incision lenticule extraction using a multimodal approach - A case report

A 42-year-old female presented with pain, photophobia, and superficial corneal infiltrates in mid-periphery in the left eye, after 2 days of uneventful bilateral SMILE procedure. Inspite of the medical treatment with fortified antibiotics, the infection spread to the interface, close to visual axis reducing UDVA from 20/16 to 20/80. Immediate surgical intervention in the form of scraping of interface lesions with 26G needle, interface wash with antibiotics and photoactivated chromophore for keratitis (PACK-CXL) was performed. After 24 h of bacterial culture Staphylococcus aureus was yielded. Interface wash and PACK-CXL was repeated after 48 h by which infiltrates reduced and early scarring was observed by 10^th post-op day. Subsequent topical steroids helped in limiting scar formation and UDVA improved to 20/30 at the final visit. Combined approach of interface wash with antibiotics and PACK-CXL may be a safe and effective modality in treating early onset infectious keratitis following SMILE surgery.

Complications of small incision lenticule extraction

The procedure of small incision lenticule extraction (SMILE) was introduced in 2011, and since then there has been an increase in the number of cases undergoing this procedure worldwide. The surgery has a learning curve and may be associated with problems in the intraoperative and postoperative periods. The intraoperative problems during SMILE surgery include the loss of suction, the occurrence of altered or irregular opaque bubble layer and black spots, difficulty in lenticular dissection and extraction, cap perforation, incision-related problems, and decentered ablation. Most of the postoperative problems are similar as in other laser refractive procedures, but with decreased incidence. The identification of risk factors, clinical features, and management of complications of SMILE help to obtain optimum refractive outcomes.

Hypersensitivity reactions after femtosecond laser small incision lenticule extraction: a case report of corneal infiltrates

BACKGROUND

Femtosecond laser corneal refractive surgery is generally considered safe and effective; however, this procedure is rarely associated with severe allergic reactions. We reported a rare case of hypersensitivity reactions which caused bilateral peripheral corneal infiltrates after femtosecond laser small incision lenticule (SMILE) surgery in a man with a history of fruits allergy.

CASE PRESENTATION

Here we report the case of a young man who developed white, ring-shaped bilateral peripheral infiltrates that appeared 1 day after an uneventful SMILE surgery. The overlying corneal epithelium was intact; the infiltrate was negative for bacterial culture, but high titers of immunoglobulin E was demonstrated in the blood. Symptomatically, a clinical diagnosis of sterile corneal infiltrates was made, and the patient was treated with topical and systemic steroids. The infiltrates were immunogenic in origin, which may be caused by the contact lenses used for suction duration in surgery. It resolved without corneal scarring in the subsequent months following steroid treatment. The patient's visual acuity improved.

CONCLUSIONS

When patients with a history of allergy who aim to perform corneal refractive surgery, surgeons must consider possible hypersensitivity reactions after treatment. More studies are needed to clarify the relationship between contact glass used in femtosecond laser corneal refractive surgery and IgE mediated hypersensitivity reactions.

Laser-assisted subepithelial keratomileusis substituted for an aborted small-incision lenticule extraction due to large black area formation

A 25-year-old woman with moderate myopia presented for refractive surgery. Bilateral femtosecond laser-assisted small-incision lenticule extraction (SMILE) was scheduled and her right eye was completed smoothly. However, during the lenticule cutting of her left eye, a large inferior black area was noted. The operation was abandoned after an immediate optical coherence tomography examination, which revealed the corneal epithelium defect with no laser scanning line at the corresponding site. The secondary surgery was assigned to laser-assisted subepithelial keratomileusis (LASEK) after 1 week. The uncorrected distance visual acuity of her left eye recovered to 20/25 on the 12th day and to 20/20 at 3-month follow-up, with ideal corneal topography profiles. Corneal epithelium defect induced by accidental alcohol contact during disinfection was suspected to cause the black area. The management of black area had to be determined according to the location and size. LASEK was a rational substitution for the aborted SMILE.

Mycobacterium abscessus subsp. bolletii keratitis: rare case reported in Brazil

In this report, we described a rare case of Mycobacterium abscessus subsp. bolletii keratitis in a young healthy male, in the absence of risk factors.

Postoperative Corneal Complications in Small Incision Lenticule Extraction: Long-Term Study

PURPOSE

To investigate the incidence and clinical results of corneal complications after small incision lenticule extraction (SMILE).

METHODS

A retrospective cohort study including 3,223 patients (6,373 eyes) who were treated for myopia or myopic astigmatism was conducted. Postoperative corneal complications were recorded. Postoperative follow-up visits were scheduled on days 1 and 7 and months 1, 3, 6, and 12.

RESULTS

Of the 6,373 cases, 432 eyes (6.8%) developed at least one corneal complication postoperatively. These included punctate epithelial erosions (3.26%), diffuse lamellar keratitis (DLK) (2.17%), corneal infiltrates (0.39%), interface debris/secretion (0.30%), interface haze (0.17%), interface foreign body (0.24%), corneal striae (0.14%), corneal edema (0.09%), and epithelial ingrowth (0.02%). Of cases with corneal complications, 308 (71.3%) had an uncorrected distance visual acuity (UDVA) of better than 20/25 and 49 (11.3%) eyes lost two or more lines of corrected distance visual acuity (CDVA) on the first day after surgery. By 3 months, only 2 eyes (0.9%) had lost two or more lines of CDVA. At 6 months, 1 eye (1.0%) did not achieve a UDVA of 20/25 as a result of stage 3 DLK, but achieved 20/20 by 1 year. The postoperative spherical equivalent in cases without complications was lower than that in cases with complications at 1 day and 1 and 3 months (P = .001, .011, and .001, respectively), but there was no statistical difference at 6 and 12 months.

CONCLUSIONS

In this large cohort study, a variety of corneal complications were noted after SMILE. Although some of these complications may temporarily affect visual recovery, most resolve with appropriate treatment. [J Refract Surg. 2019;35(3):146-152.].

Bilateral Non-tuberculous Mycobacterial Keratitis After Small Incision Lenticule Extraction

PURPOSE

To report a case of bilateral non-tuberculous mycobacterial keratitis after small incision lenticule extraction (SMILE) that was successfully treated with oral and topical fortified antibiotics.

METHODS

Case report and literature review.

RESULTS

An otherwise healthy 21-year-old woman presented with culture-proven bilateral Mycobacterium abscessus keratitis 8 days after undergoing SMILE, showing multiple white stromal infiltrates in the interface in both eyes. Progressive, diffuse flap edema followed by pocket abscess, exudation in the anterior chamber, granulation tissue formation in the pocket, intrastromal neovascularization, and eventually partial resolution of corneal opacity were noted after topical and oral antibiotic treatment for 6 months. Her corrected distance visual acuity was 20/32 and 20/50 in the right and left eyes, respectively, 12 months after initial presentation.

CONCLUSIONS

This is the first report of successful medical management of bilateral non-tuberculous mycobacterial keratitis after SMILE. The manifestations are different from and even more difficult to treat than those of keratitis after LASIK. [J Refract Surg. 2018;34(9):633-636.].

[SMILE (Small Incision Lenticule Extraction) among the corneal refractive surgeries in 2018 (French translation of the article)]

Refractive surgery is a field in constant evolution. In recent years, a new procedure has appeared under the name SMILE (Small Incision Lenticule Extraction). This technique, carried out solely with a femtosecond laser, should make it possible to better preserve corneal innervation and biomechanics. After a detailed review of the technique itself, we then focus on the scientific evidence for the safety and efficacy of SMILE and its current indications. Advantages of SMILE will be discussed in comparison to disadvantages of the conventional techniques, particularly concerning dry eye and the risk of corneal ectasia with LASIK. Lastly, the current limitations of SMILE (indications, retreatment) are discussed, and future applications are considered regarding improvements in the technique.

SMILE (Small Incision Lenticule Extraction) among the corneal refractive surgeries in 2018

Refractive surgery is a field in constant evolution. In recent years, a new procedure has appeared under the name SMILE (SMall Incision Lenticule Extraction). This technique, carried out solely with a femtosecond laser, should make it possible to better preserve corneal innervation and biomechanics. After a detailed review of the technique itself, we then focus on the scientific evidence for the safety and efficacy of SMILE and its current indications. Advantages of SMILE will be discussed in comparison to the conventional techniques, particularly concerning dry eye and the risk of corneal ectasia related to LASIK. Lastly, the current limitations of SMILE (indications, retreatment) are discussed, and future applications are considered regarding new improvements in the technique.

Bilateral simultaneous infective keratitis

AIM

To analyze the demographics, risk factors, clinical and microbiological characteristics of cases of bilateral simultaneous infective keratitis.

METHODS

In this retrospective case series, patients with clinical evidence of bilateral simultaneous infective keratitis were identified from January 1, 2011 to August 31, 2016. Demographics, risk factors, clinical and microbiological characteristics, and treatment outcomes were analyzed.

RESULTS

Five patients (ten eyes) with bilateral simultaneous infective keratitis were identified. The mean age was 32.8 years (SD,±8.8; range, 24-44). All the patients were disposable soft contact lens wearers before presentation. The average size of the infiltrate was 4.76mm² (SD±9.0; range, 0.2-31.34). A total of 4 types of bacteria were isolated, with Pseudomonas aeruginosa being the most frequently isolated bacteria involving 5 eyes of four patients. Infection resolved with medical treatment in 9 eyes, 1 patient required therapeutic corneal transplantation for impending corneal perforation. The average time taken for infection to resolve was 6.7days (SD±4.5; range, 2-16).

CONCLUSIONS

In this case series, the most common risk factor of bilateral simultaneous microbial keratitis was use of soft disposable contact lens and the most commonly isolated bacteria was Pseudomonas aeruginosa. Bilateral simultaneous infective keratitis is uncommon and is a serious complication of contact lens use in immunocompetent adult patients.