Infectious keratitis related to orthokeratology

Chronic canaliculitis with canaliculoliths due to Providencia stuartii infection

Canaliculitis, inflammation of the lacrimal canaliculi, can be caused by numerous pathogens, most commonly bacteria from the genera Actinomyces, Streptococcus, and Staphylococcus. Primary canaliculitis often requires surgical canaliculolith removal and appropriate antibiotic coverage. The authors report a case of a 77-year-old woman with a history of punctal plugs who presented with chronic canaliculitis with canaliculoliths that grew Providencia stuartii. P. stuartii has not previously been described as a cause of primary canaliculitis. This case highlights a new organism that causes canaliculitis with canaliculoliths and stresses the importance of speciation and antibiotic sensitivity testing following canaliculotomy and curettage. P. stuartii should be considered in the differential for bacterial canaliculitis with canaliculoliths, especially in patients with persistent symptoms on topical antibiotic therapy without canaliculotomy.

The Role of Atropine in Preventing Myopia Progression: An Update

Several approaches have been investigated for preventing myopia progression in children and teenagers. Among them, topical atropine has shown promising results and it is being adopted in clinical practice more and more frequently. However, the optimal formulation and treatment algorithm are still to be determined. We discuss the pharmacokinetic, pharmacodynamic, clinical, and tolerability profile revealed first by the multicenter, randomized ATOM 1 and 2 trials and, more recently, by the LAMP Study. Results from these trials confirmed the efficacy of low-concentration atropine with a concentration-dependent response. Although atropine at 0.025% and 0.05% concentrations has shown the most encouraging results in large-scale studies, these formulations are not yet commonplace in worldwide clinical practice. Moreover, their rebound effect and the possibility of reaching a stabilization effect have not been fully investigated with real-life studies. Thus, further larger-scale studies should better characterize the clinical efficacy of atropine over longer follow-up periods, in order to define the optimal dosage and treatment regimen.

Acanthamoeba keratitis related to contact lens use in a tertiary hospital in China

Background

To report the clinical and microbiological features of Acanthamoeba keratitis (AK) related to contact lens use in a tertiary hospital in China.

Methods

In this retrospective study, the medical results of 61 cases of AK related to contact lens use from January 2000 to December 2017 were reviewed. The data included patients’ demographics, lens type, history, risk factors, disease stages, corneal scraping and culture reports, and treatments. Moreover, genotypic identification of some of the isolates was carried out with a PCR assay and sequence analysis of the 18S ribosomal DNA gene.

Results

There were 64 eyes included in the study. A total of 32.8% of the patients wore soft contact lenses, and 67.2% of patients used overnight orthokeratology. In the cases (20 eyes) in the early stage, 65% (13 eyes) had positive results according to Giemsa-stained smears, and 0.9% sodium chloride (NaCl) wet mounts revealed trophozoites in 7 eyes (35%). Six eyes (30%) were diagnosed by confocal microscopy combined with clinical signs. In the orthokeratology patients, 87.8% (36/41) rinsed their lenses and/or cases with tap water; 55% of soft-lens wearers wore their lenses while showering. The genotype of 9 isolates was determined, and all the strains belonged to genotype T4. In the orthokeratology group, the number of patients who required therapeutic penetrating keratoplasty after 2005 was less than that before 2005 (chi-square test, χ² = 4.209, P = 0.04).

Conclusions

More than two-thirds of the cases were associated with orthokeratology. Examinations with Giemsa-stained smears, 0.9% NaCl wet mounts and confocal microscopy should be performed for patients who are highly suspected of having early-stage AK to help with early diagnosis. In the orthokeratology group, the rate of therapeutic keratoplasty after 2005 was less than that before 2005.

Electronic supplementary material

The online version of this article (10.1186/s12886-019-1210-2) contains supplementary material, which is available to authorized users.

The Influence of Overnight Orthokeratology on Ocular Surface and Meibomian Gland Dysfunction in Teenagers with Myopia

Purpose

The aim of this study was to investigate the effect of overnight orthokeratology (OOK) on ocular surface and meibomian gland dysfunction in teenagers with myopia.

Methods

A total of 59 subjects were recruited in this prospective study. The following tests were performed before and after 1, 3, 6, 12, and 24 months of OOK lens wear, including ocular surface disease index (OSDI) questionnaire, slit-lamp examination, and Keratograph 5M.

Results

No infectious keratitis occurred during the study. OSDI scores increased gradually and reached the maximum at 6 months of OOK wear (P < 0.001). The meniscus height was significantly increased at 1 and 3 months after the initiation of OOK (P=0.006, P=0.035). The corneal fluorescein staining at 1, 3, 6, 12, and 24 months after wearing OOK were all increased than the prewearing level with significant difference (P=0.014, P=0.036, P < 0.001, P < 0.001, and P=0.008, respectively). The first and the average tear film NIKBUT were all higher than the prewearing level, but there was no significant difference between every follow-up time points (P > 0.05). The lid margin abnormalities were significantly increased (P=0.003, P=0.038, and P=0.015) at 6, 12, and 24 months after the initiation of OOK. There was no significant difference in the meibomian gland orifice scores at each follow-up time points compared to the prewearing level (P > 0.05). The meibomian gland lipid secretion scores after wearing OOK were higher than those of the prewearing level, however, without statistically significant difference (P > 0.05). No significant differences of the degree of difficulty of lipid excretions were detected after the initiation of OOK (P > 0.05). There was no significant difference in meibomian gland dropout scores between all follow-up time points and the prewearing level (P=1.000).

Conclusion

OOK increased the symptoms of dry eye and decreased the function of tear film by affecting the meniscus height and BUT. OOK did not affect the function of meibomian glands.Clinical Study registration number: ChiCTR18000185708.

Prevention of Progression in Myopia: A Systematic Review

The prevalence of myopia has increased worldwide in recent decades and now is endemic over the entire industrial world. This increase is mainly caused by changes in lifestyle and behavior. In particular, the amount of outdoor activities and near work would display an important role in the pathogenesis of the disease. Several strategies have been reported as effective. Spectacles and contact lenses have shown only slight results in the prevention of myopia and similarly ortokerathology should not be considered as a first-line strategy, given the high risk of infectious keratitis and the relatively low compliance for the patients. Thus, to date, atropine ophthalmic drops seem to be the most effective treatment for slowing the progression of myopia, although the exact mechanism of the effect of treatment is still uncertain. In particular, low-dose atropine (0.01%) was proven to be an effective and safe treatment in the long term due to the lowest rebound effect with negligible side effects.

Acanthamoeba keratitis in patients wearing scleral contact lenses

PURPOSE

To report a series of cases of Acanthamoeba keratitis (AK) in scleral lens wearers with keratoconus to determine whether this type of contact lens presents a greater risk for development of infection.

METHODS

This study reports three patients who wore scleral contact lenses to correct keratoconus and developed AK. The diagnoses of AK were established based on cultures of the cornea, scleral contact lenses, and contact lens paraphernalia. This study investigated the risk factors for infections.

RESULTS

The possible risks for AK in scleral contact lens wearers are hypoxic changes in the corneal epithelium because of the large diameter and minimal tear exchange, use of large amounts of saline solution necessary for scleral lens fitting, storing the scleral lens overnight in saline solution rather than contact lens multipurpose solutions, not rubbing the contact lens during cleaning, and the space between the cornea and the back surface of the scleral lens that might serve as a fluid reservoir and environment for Acanthamoeba multiplication. Two patients responded well to medical treatment of AK; one is still being treated.

CONCLUSIONS

The recommendations for use and care of scleral contact lenses should be emphasized, especially regarding use of sterile saline (preferably single use), attention to rubbing the lens during cleaning, cleaning of the plunger, and overnight storage in fresh contact lens multipurpose solutions without topping off the lens solution in the case.

Infectious keratitis and orthokeratology lens use: a systematic review

PURPOSE

Myopia is a prevalent condition among Asians. Orthokeratology lens has gained popularity as a method of myopia control. This systematic review is to summarize the clinical profile of infectious keratitis in association with orthokeratology lens wear.

METHODS

We searched in the PubMed and EMBASE for articles adopting the search strategy "(orthokeratology lens OR orthokeratology) AND (bacterial eye infection OR keratitis OR cornea ulcer OR microbial keratitis OR bacterial keratitis)", from the start date of the databases to August 23, 2016. Articles reporting infectious keratitis in orthokeratology lens users with data of individual cases were considered eligible for this systematic review. We recorded the outcome measures including method of diagnosis, etiological agents, duration and mode of treatment and treatment outcomes.

RESULTS

Our literature search yielded 172 papers. After removing duplicated and irrelevant reports, we included 29 articles for data analysis, involving 173 eyes. Among all reported cases, the mean age at presentation was 15.4 ± 6.2 years, with a female preponderance (male-to-female ratio 1:1.7). Positive microbiological cultures were reported in 69.4% of cases, with Pseudomonas aeruginosa and Acanthamoeba being the most common etiological agents. The mean duration of hospitalization was 7.7 ± 6.7 days. Mean LogMAR visual acuity at presentation was 1.17 ± 0.78, increased to 0.33 ± 0.41 at final visit (p < 0.001).

CONCLUSIONS

Despite early intervention and treatment, the majority of infections resulted in the formation of corneal scars and almost 10% of eyes needed surgical treatment. Timely awareness and treatment of keratitis should be emphasized to the users.

Interventions to Reduce Myopia Progression in Children

Efforts to reduce the progression of myopia in childhood are on the rise, due to an increasing incidence of myopia worldwide and its associated sight-threatening complications. Interventions are aimed at reducing myopia in childhood and include environmental considerations, spectacles, contact lenses, and pharmacological agents. We reviewed recent literature with interventions aimed at reducing myopia progression in children and found that a number of interventions were significant in reducing the progression of myopia. Of these interventions, atropine showed the largest dose-related effect on myopia progression control. Although higher doses are associated with side effects of pupil dilatation, loss of accommodation, near vision blur, and rebound phenomenon, low-dose atropine has also been shown to provide effective myopia control with minimal side effects and rebound. To a lesser degree, bifocal soft contact lenses have also been shown to be effective in reducing the progression of myopia, though compliance is an issue. Similarly, orthokeratology lenses have also been shown to be effective in reducing axial length elongation and myopia progression, though long-term data on its rebound effects are unavailable.

Case report: Providencia stuartii conjunctivitis

Purpose

The purpose of this study is to report a case of Providencia stuartii conjunctivitis.

Methods

This study is a retrospective chart review of a patient with persistent conjunctivitis.

Results

We report the first case of P. stuartii conjunctivitis. Our patient was an elderly man living in a nursing home who was likely immunocompromised from longstanding diabetes mellitus. A conjunctival swab culture was able to identify the infecting bacteria and its antibiotic susceptibility. The conjunctivitis was successfully treated with vancomycin drops and oral sulfamethoxazole and trimethoprim.

Discussion

P. stuartii is an increasingly common bacterium found in the urine of immunocompromised nursing home residents with indwelling Foley catheters. While it has rarely been found to cause ocular infections, P. stuartii may be suspected in elderly, immunocompromised nursing home residents.

Orthokeratology-associated infectious keratitis in a tertiary care eye hospital in Hong Kong

PURPOSE

To analyze cases of orthokeratology-associated infectious keratitis managed in a tertiary care eye hospital in Hong Kong between 2003 and 2013.

DESIGN

Retrospective study.

METHODS

Case records of patients with infectious keratitis attributable to orthokeratology contact lenses were analyzed. Data analyzed included clinical features, microbiological evaluation, and treatment outcomes.

RESULTS

A total of 23 patients were included (16 female, 7 male, mean age: 15.0 ± 4.2 years; range: 9-23 years). All patients were using overnight orthokeratology for an average of 2.7 ± 2.8 years (range: 3 months - 10 years) before the onset of infection. Clinical features included corneal infiltrate (n = 14, 60.9%) and corneal perineuritis (n = 12, 52.2%). Fifteen eyes (65.2%) had a positive microbiological culture obtained from corneal scrapings. The most commonly isolated organism was Pseudomonas aeruginosa (n = 6), followed by coagulase-negative Staphylococcus (n = 5) and Acanthamoeba (n = 3). Five cases of Pseudomonas aeruginosa and 5 cases of Acanthamoeba were identified from contact lenses or contact lens solution. The mean duration from disease onset to remission was 31.9 ± 34.9 days (range: 6-131 days). All patients responded to medical treatment, and no emergency surgical intervention was needed. The best-corrected logMAR visual acuity improved significantly from 0.62 ± 0.51 (20/83 Snellen) to 0.15 ± 0.20 (20/28 Snellen) (Wilcoxon signed rank test, P < .001).

CONCLUSIONS

Orthokeratology-associated infectious keratitis continues to be a serious problem, especially in regions with high prevalence of myopia. Early clinical and microbiological diagnosis and intensive treatment can improve final visual outcomes.

Orthokeratology lens related infections

Orthokeratology is a reversible technique that temporarily changes the curvature of the cornea with the aim of addressing refractive errors. The United States Food and Drug Administration (FDA) granted approval for using reverse geometry contact lenses to correct myopia without any age restriction. Information from the pre-market applications to the FDA was rated as level II evidence. Another unapproved use of overnight orthokeratology is for the prevention of myopic progression. Although orthokeratology is advocated to reduce myopic progression, there are limited long-term studies with substantial evidence of its benefits. Much of this evidence comes from non-robust experimental studies using historical or self-selected controls with relative high dropout rates. Although some positive results have been published in temporarily reducing the myopic refractive error and its progression, the use of these lenses can be associated with serious complications such as microbial keratitis. Microbial keratitis is a potentially vision-threatening adverse response associated with contact lens wear. In fact, contact lens wear has been shown to be the predominant risk factor of microbial keratitis in some developed countries. Most of the published cases on overnight orthokeratology related microbial keratitis occurred in children or adolescents. Parents considering orthokeratology must make an informed decision about its temporary benefit and its potential for permanent loss of vision. The ophthalmic community should be reminded of the potential complications of orthokeratology.

Rapid diagnosis of acanthamoeba keratitis using non-nutrient agar with a lawn of E. coli

Background

A patient presented with a corneal foreign body in his only eye. He was treated with prophylactic antibiotics and sent home, but deteriorated.

Findings

He returned to the hospital 5 days later, and on slit-lamp examination, there was ciliary injection, corneal oedema and a 1 mm × 1 mm corneal abscess with mild anterior uveitis. Corneal scrapings were taken for culture on a non-nutrient agar with a lawn of Escherichia coli, on chocolate agar and on blood agar. He was treated with fortified gentamicin and cefazolin drops. He improved and was discharged 4 days after admission. On day 5, the culture results showed acanthamoeba. He was brought back to the hospital and treated with hourly chlorhexidine drops, ofloxacin six times daily and neomycin/dexamethasone drops once daily. On day 7, he was discharged to continue treatment at home, at which time his visual acuity in that eye was 6/9, and slit-lamp examination showed punctate keratitis and a stromal opacity with mild peripheral infiltration.

Conclusions

Culture on non-nutrient agar with a lawn of E. coli is a rapid, reliable and less invasive alternative to corneal biopsy for the diagnosis of acanthamoeba infection. We suggest using this method where acanthamoeba is suspected. Owing to the risk of corneal abscess, orthokeratology should be avoided in an amblyopic patient or an only eye. Acanthamoeba infection may be masked by other eye diseases.

Trends in microbial keratitis associated with orthokeratology

PURPOSE

Orthokeratology is a clinical technique that uses reverse-geometry rigid gas-permeable contact lenses to alter corneal shape to provide temporary reduction of refractive error. Microbial keratitis is the most severe, potentially vision-threatening adverse response associated with orthokeratology contact lens wear. This article aims to review all reported cases of confirmed and presumed microbial keratitis associated with orthokeratology and to examine trends in microbial keratitis in orthokeratology over time.

METHODS

Cases of microbial keratitis associated with orthokeratology were identified from case reports published in the optometric, ophthalmologic, and vision science literature and published in abstract form for papers or posters presented at optometric or ophthalmologic conferences.

RESULTS

A total of 123 cases of microbial keratitis associated with orthokeratology have been reported since 2001, dating back to 1997. Most patients were female, East Asian, and aged between 8 and 15 years. The infectious organism was implicated as Pseudomonas aeruginosa for 46 (38%) of these cases and as Acanthamoeba species for 41 (33%) cases. The peak year for occurrence of microbial keratitis was 2001 and accounted for more than half (64 [52%] of 123) of all reported cases. All cases in this year were reported from East Asia, including China (47 cases), Taiwan (11 cases), and Hong Kong (6 cases).

CONCLUSIONS

Although there has been an increasing number of reports of microbial keratitis associated with orthokeratology since 2001, most (85 [69%] of 123) of these cases occurred in East Asia, particularly in China and Taiwan, during a relatively short period, when regulation of this modality was limited. The high prevalence of cases of Acanthamoeba keratitis reported with this modality emphasizes the importance of eliminating the use of tap water in care regimens for overnight orthokeratology.

Good visual outcome after prompt treatment of acanthamoeba keratitis associated with overnight orthokeratology lens wear

PURPOSE

To describe a patient with a good visual outcome after prompt treatment of Acanthamoeba keratitis as a complication of overnight orthokeratology lens wear.

METHODS

Interventional case report.

RESULTS

A 9-year-old boy experienced pain, photophobia, and redness in his right eye 3 days after visiting a swimming pool. He had been wearing overnight orthokeratology lenses for 5 months for the correction of moderate myopia in both eyes. On examination, best-corrected visual acuity in the right eye was 20/40. A diagnosis of Acanthamoeba keratitis with the presence of the classic feature of perineural infiltrates was made. The patient responded well to treatment with polyhexamethylene biguanide and propamidine isethionate (Brolene). Culture of corneal scrapings and contact lens solution showed heavy growth of Acanthamoeba. Treatment was tapered gradually during the next 4 months, and the final best-corrected visual acuity was 20/25.

CONCLUSIONS

Acanthamoeba keratitis may be a vision-threatening complication associated with overnight orthokeratology lens wear. It is essential for eye care professionals to fully explain and warn parents of the potential downsides that may be associated with orthokeratology. Ophthalmologists should have a high level of suspicion of this complication because prompt diagnosis and treatment can result in good visual outcome.

Contact lens-induced changes in the anterior eye as observed in vivo with the confocal microscope

The availability of the confocal microscope over the past decade has allowed clinicians and researchers to refine their understanding of the physiological and pathological basis of the ocular response to contact lens wear, and to discover previously unknown phenomena. Mucin balls, which form in the tear layer in patients wearing silicone hydrogel lenses, can penetrate the full thickness of the epithelium, leading to activation of keratocytes in the underlying anterior stroma. Epithelial cell size increases in response to all forms of lens wear, with lenses of higher oxygen transmissibility (Dk/t) interfering least with the normal process of epithelial desquamation. A higher density of Langerhans' cells is observed in the layer of the sub-basal nerve plexus among contact lens wearers, suggesting that contact lens wear may be altering the immune status of the cornea. Dark lines and folds are observed in the oedematous cornea in response to contact lens wear. Mechanical stimulation of the corneal surface, due to the physical presence of a contact lens, and the consequent release of inflammatory mediators, is the likely cause of reduced keratocyte density associated with lens wear. Highly reflective stromal 'microdot deposits' are observed throughout the entire stroma in higher numbers in lens wearers. 'Blebs' in the endothelium have a bright centre surrounded by a dark annular shadow; this appearance is explained with the aid of an optical model. The confocal microscope has considerable clinical utility in diagnosing Acanthamoeba and fungal keratitis. At the limbus, contact lenses can induce structural changes such as increases in basal epithelial cell size. An increased number of rolling leucocytes is observed in limbal vessels in response to low Dk/t lenses. It is concluded that the confocal microscope has considerable utility in contact lens research and practice.

Infectious keratitis

PURPOSE OF REVIEW

Infectious keratitis is a medical emergency. Improper management can lead to marked loss of vision. This review identifies recent trends in the study of infectious keratitis.

RECENT FINDINGS

A multicountry outbreak of Fusarium keratitis emphasizes that contact lens wear is a major risk factor for infectious keratitis. Acanthamoeba and fungal keratitis are the most expensive forms of infectious keratitis to treat. Noninvasive methods and molecular techniques have improved diagnosis of infectious keratitis. Fortified topical antibiotics and fluoroquinolones are still the mainstay of bacterial keratitis therapy. Voriconazole and new routes of administration of conventional antifungals appear promising for fungal keratitis. Antivirals and amelioration of host inflammatory response are promising for viral keratitis; the host response is also crucial in pathogenesis of Pseudomonas aeruginosa keratitis. Trauma-induced bacterial and fungal keratitis and contact lens-associated keratitis are preventable entities.

SUMMARY

Improved modalities of diagnosis and treatment have improved the outcome of infectious keratitis, but therapy of acanthamoebal, fungal and P. aeruginosa keratitis is still a challenge. Effective strategies must neutralize potential risk factors and counter host response overactivity without impairing killing of infecting microorganisms. Trauma-induced bacterial and fungal keratitis can be prevented.

Acanthamoeba keratitis related to orthokeratology

PURPOSE

To report four cases of Acanthamoeba keratitis related to the overnight wearing of orthokeratology lenses.

METHODS

Four patients had histories of overnight wearing of orthokeratology lenses when they presented with corneal ulcers. They had used a contact lens care system irregularly with tap water.

RESULTS

The organism isolated by corneal scraping was Acanthamoeba. The patients were treated with polyhexamethylene biguanide (PHMB) and chlorhexidine, resulting in a resolution of ocular inflammation.

CONCLUSION

The risk of Acanthamoeba keratitis as a potential complication of overnight orthokeratology should be considered, especially in patients with over one-year duration of contact lens wearing. Careful contact lens management is needed and tap-water rinsing should be eliminated from the lens care regimen.

Efficacy of multipurpose solutions for rigid gas permeable lenses

The use of multipurpose solutions for cleaning and disinfecting rigid gas permeable lenses has replaced single purpose solutions, but there are no reports of the efficacy of these multipurpose solutions, or of the effects of storage conditions on their disinfecting capacities. This study investigated activity against four bacterial and two fungal species, and the effects of storage in a refrigerator, at room temperature, at elevated temperature in both dry and humid conditions and with exposure to sunlight. The disinfecting solutions were challenged with the micro-organisms initially upon opening and then at 2-weekly intervals up to 12 weeks after being stored under the different conditions. Solutions were opened daily to simulate use. One solution failed to meet Food and Drug Administration (FDA) criteria to reduce numbers of bacteria by three log dilutions and of fungi by one log dilution. Storage reduced activity of all solutions over the 12-week period, but not below the requirements of the FDA. Storage in the refrigerator tended to reduce disinfecting capacity more quickly. Multipurpose solutions for rigid gas permeable (RGP) lenses lose activity over the 3 months recommended time of use but remain satisfactory for use over this time in the conditions tested. Practitioners need to remind patients to replace their solutions regularly and should advise against storage in the refrigerator. Multipurpose solutions for RGP lenses have simplified cleaning and disinfecting processes and the current formulations have improved disinfecting capacity compared to former disinfecting solutions, which is particularly important for wearers of orthokeratology lenses.

Corneal reshaping: is it a good alternative to refractive surgery?

PURPOSE OF REVIEW

To review current literature on overnight corneal reshaping and present this mode of vision correction in its current state.

RECENT FINDINGS

Overnight corneal reshaping uses specially designed rigid gas-permeable contact lenses. It is effective in temporarily reducing or eliminating low to moderate myopia. This nonsurgical mode of vision correction allows for good unaided vision during waking hours. There are reports of young patients experiencing serious adverse events, particularly bacterial and Acanthamoeba keratitis while using these lenses, although incidence rates are unknown.

SUMMARY

Overnight corneal reshaping is an alternative to refractive surgery and must continue to be studied and monitored to establish its safety.