Effects of daily and overnight wear of hyper-oxygen transmissible rigid and silicone hydrogel lenses on bacterial binding to the corneal epithelium: 13-month clinical trials

Predisposing Factors, Clinical Presentations, and Outcomes of Contact Lens-Related Pythium Keratitis

PURPOSE

To describe predisposing factors, clinical presentations, and treatment outcomes of contact lens (CL)-related Pythium keratitis.

METHODS

This was an 11-year retrospective study of CL-related Pythium keratitis conducted from 2009 to 2019. Six eyes of 6 patients were identified. Demographics, predisposing factors, CL history, clinical presentation, diagnostic tests, treatments, and outcomes were reviewed.

RESULTS

Mean age of the patients was 34 years (SD 16.3 years) with equal proportion between male and female patients. Five of 6 patients (83.3%) used soft CL, whereas 1 patient used rigid gas permeable lens. All patients had a history of water contamination (tap water and water from river and sea). Mean duration from the onset was 7.8 days (range 4-14 days). Mean size of the corneal lesion was 3.33 mm (SD 1.31 mm) in width. The typical feature of tentacle-like lesions radiating in a reticular pattern was observed in all patients. Feathery edge (1 eye), satellite lesions (2 eyes), and radial keratoneuritis (2 eyes) were also found. Every patient received therapeutic penetrating keratoplasty because of failed medical treatments. One patient subsequently underwent enucleation. Globe salvage was achieved in 5 patients (83.33%).

CONCLUSIONS

Awareness of the history of water contamination, recognition of specific clinical features of Pythium keratitis, and performing surgical treatment are key for achieving globe salvage in patients with CL-related Pythium keratitis.

Contact lens wear and the diabetic corneal epithelium: A happy or disastrous marriage?

Diabetes mellitus is an epidemic in the US and abroad. With the advent of new contact lens technology, the use of contact lenses as glucose sensors in lieu of the traditional finger stick is quickly becoming realized. This has the potential to rapidly expand the contact lens market into this growing patient population. The independent cellular and physiological effects of contact lens wear and diabetes on the corneal epithelium have been described. However, little evidence exists to date to support whether there is increased risk associated with contact lens wear in diabetes. The focus of this review is to discuss what is known about the cellular effects of contact lenses on the corneal epithelium, the pathophysiological changes in the corneal epithelium that occur in diabetes, and whether an increased risk for corneal epithelial damage and/or infection may negatively impact safety in diabetic contact lens wearers. Available data indicates that there are inherent risks associated with contact lens wear in diabetics. Importantly, eye care practitioners fitting contact lenses in the diabetic patient need to carefully consider the duration of disease, the level of glycemic control, the presence of retinopathy, and the patient's overall health.

Microbiological study of therapeutic soft contact lenses used in the treatment of recurrent corneal erosion syndrome

OBJECTIVE

To determine the bacteriological spectrum of the removed therapeutic soft contact lenses (TSCLs) and to establish efficacy of prophylactic antibiotics on TSCLs used for 2 weeks for treatment of patients with recurrent corneal erosion syndrome (RCES).

METHODS

This study included idiopathic RCES treated using highly oxygen-permeable silicone hydrogel contact lenses (CLs), and treated 4 times per day with topical tobramycin 3% for 2 weeks. After TSCLs were applied for 2 weeks, the lenses were removed with sterile forceps under which a speculum was inserted, and placed on blood agar with the inner face down. The TSCLs were analyzed for bacterial colonization, and antibiotic susceptibility tests were performed for the isolates, using disk diffusion.

RESULTS

Of the 40 lenses analyzed, 9 (22.5%) yielded positive cultures. Staphylococcus epidermidis was the most commonly isolated microorganism; there were five methicillin-sensitive coagulase-negative staphylococci and two methicillin-resistant coagulase-negative staphylococci. Furthermore, we found two lenses that were colonized by Enterobacter gergoviae and Citrobacter freundii. All cultured bacteria showed intermediate or complete sensitivity to ciprofloxacin, tigecycline, and tobramycin. Despite bacterial colonization in 9 CLs, no clinical signs of infectious keratitis were found in any of the patients with prophylactic topical tobramycin 3%.

CONCLUSIONS

In case of using TSCLs for 2 weeks, tobramycin or ciprofloxacin may be useful as prophylactic topical antibiotics for preventing secondary corneal infections. Considering currently growing incidence of ciprofloxacin-resistant ocular isolates, tobramycin seems to be a reasonable prophylactic topical antibiotic susceptible broad spectrum of bacteria in clinics.

Cosmetic Contact Lenses and the Pupillary Light Reflex in Trauma

The presence of dilated pupils that have no direct or consensual response to light after traumatic brain injury is an ominous sign, potentially heralding severe intracranial damage. We describe a case in which the presence of tinted contact lenses directly caused misinterpretation of the pupillary light reflex and discuss the clinical importance of this observation.

Keratitis with Elizabethkingia meningoseptica occurring after contact lens wear: a case report

To report keratitis with Elizabethkingia meningoseptica, which occurred in a healthy patient after wearing contact lenses for 6 months. A 24-year-old male patient visited our hospital with ocular pain. This patient had a history of wearing soft contact lenses for 6 months, about 10 hours per day. At initial presentation, slit lamp examination showed corneal stromal infiltrations and small epithelial defect. Microbiological examinations were performed from corneal scrapings, contact lenses, and the contact lens case and solution. The culture results from contact lenses, contact lens case and solution were all positive for Elizabethkingia meningoseptica. Thus, we could confirm that the direct cause of keratitis was contamination of the contact lenses. The patient was treated with 0.3% gatifloxacin. After treatment, the corneal epithelial defect was completely healed, and a slight residual subepithelial corneal opacity was observed. We diagnosed keratitis with Elizabethkingia meningoseptica in a healthy young male wearing soft contact lenses. We conclude that Elizabethkingia meningoseptica should be considered as a rare but potential pathogen for lens-related keratitis in a healthy host.

The association of contact lens solution use and Acanthamoeba keratitis

PURPOSE

To investigate Acanthamoeba keratitis (AK) risk factors. Diagnosis of AK, a rare but serious corneal infection, has recently increased significantly at the University of Illinois at Chicago (UIC) Cornea Service.

DESIGN

Retrospective case-control study.

METHODS

settings: University, tertiary care hospital. patients: Fifty-five AK cases with contact lens use were diagnosed between May 1, 2003 and September 15, 2006. Clinic-matched controls with contact lens use were recruited. Subjects completed surveys targeting lens hygiene, contact lens solution use, and water exposure. main outcome measure: Acanthamoeba keratitis.

RESULTS

Thirty-nine (73.6%) cases and 113 (65.3%) controls participated; 38 cases had complete contact lens data. Thirty-five of 38 cases (92.1%) and 47 of 100 controls (47.0%) used soft lenses. Analysis was performed on 30 cases and 39 controls with matched pairs with soft lens use. Exclusive use of Advance Medical Optics (AMO) Complete MoisturePlus Multi-Purpose Solution was independently associated with AK in multivariable analysis (55.2% vs 10.5%; odds ratio [OR], 16.67; 95% confidence interval [CI] 2.11 to 162.63; P = .008). However, 38.8% of cases reported no use of AMO Complete MoisturePlus Multi-Purpose Solution either alone or in combination with other solutions. Although not statistically significant, additional hygiene-related variables (solution "reuse," lack of "rubbing," and showering with lenses) suggest a pattern of risk.

CONCLUSIONS

AMO Complete MoisturePlus Multi-Purpose Solution use is independently associated with AK among soft contact lens users. However, it does not explain all cases, suggesting additional factors. Further research into environmental risk factors and hygiene practices is warranted, especially considering this is the second outbreak of an atypical, contact lens-related infection.

Targeting Contact Lens Induced Dryness and Discomfort: What Properties Will Make Lenses More Comfortable

There are about 35 million contact lens wearers in North America, and about half of them are symptomatic of dryness and discomfort, more commonly experienced at the end of the lens wearing day. Most of these contact lens wearers do not suffer from true dry eye, which is a pervasive and ubiquitous disease or condition that affects many millions of people in North America. It seems fairly clear that the lens causes the eye to become uncomfortable or "dry," and unless it is effectively remedied, the patient will most likely discontinue lens wear. This review describes the dryness and discomfort effects of contact lenses and how contact lens properties with novel solutions have the potential for eliminating or alleviating these symptoms.

Silicone Hydrogel Contact Lenses and the Ocular Surface

For 30 years, contact lens research focused on the need for highly oxygen-permeable (Dk) soft lens materials. High Dk silicone hydrogel contact lenses, made available in 1999, met this need. The purpose of this review is to examine how silicone hydrogel lens wear affects the ocular surfaces and to highlight areas in which further research is needed to improve biocompatibility. Silicone hydrogel lenses have eliminated lens-induced hypoxia for the majority of wearers and have a less pronounced effect on corneal homeostasis compared to other lens types; however, mechanical interaction with ocular tissue and the effects on tear film structure and physiology are similar to that found with soft lens wear in general. Although the ocular health benefits of silicone hydrogel lenses have increased the length of time lenses can be worn overnight, the risk of infection is similar to that found with other soft lens types, and overnight wear remains a higher risk factor for infection than daily wear, regardless of lens material. Future contact lens research will focus on gaining a better understanding of the way in which contact lenses interact with the corneal surface, upper eyelid, and the tear film, and the lens-related factors contributing to infection and inflammatory responses.

Infectious keratitis related to overnight orthokeratology

PURPOSE

To report the microbial culture results, clinical course, and visual outcomes for infectious keratitis related to overnight orthokeratology.

METHODS

The records of patients with infectious keratitis related to overnight orthokeratology who presented to a tertiary referral center from April 2000 to March 2003 were retrospectively reviewed.

RESULTS

Twenty patients (21 eyes) were included; 1 patient had bilateral infections. The average age of the patients was 14 years. The average period between the time the patient started the overnight orthokeratology program and the onset of infectious keratitis was 23 months. Thirteen of the 21 eyes were culture positive. Organisms cultured were Pseudomonas aeruginosa (n = 9), coagulase-negative Staphylococcus species (n = 2), Serratia marcescens (n = 1), and Acathamoeba species (n = 1). All patients responded well to medical antimicrobial treatment. Final best spectacle-corrected visual acuity ranged from 20/20 to 20/100.

CONCLUSIONS

Infectious keratitis is a potential complication of overnight orthokeratology that may cause significant visual impairment. Parents of children who consider overnight orthokeratology should evaluate the benefit of temporary myopia reduction and the risk of infection.

A Review of the Holden–Mertz Criteria for Critical Oxygen Transmission

PURPOSE

Holden and Mertz established the foundations for the new generation of silicone hydrogel contact lenses for daily and extended wear in 1984. Absence of lens-induced corneal swelling was their premise and although this was possible with daily wear, the goal with extended wear seemed almost impossible because of the limitation of hydrogel materials. Experience with extended and daily wear of disposable contact lenses during the last 2 decades and, more recently, with silicone hydrogels has led to the reconsideration of the validity of the findings of Holden and Mertz.

RESULTS

A pivotal influence on the Holden and Mertz critical Dk/t value for closed-eye lens wear was exerted by two numbers: the no-lens wear corneal edema level (4%) and the silicone lens data point (Dk/t of 182x10, closed-eye edema level of 2.6%). Subsequent publications appear to give a more accurate assessment of the no-lens closed-eye corneal edema level, and there are also more recent measurements of silicone hydrogel lens Dk/t and corneal edema responses.

CONCLUSIONS

It now appears that the Holden and Mertz criteria for extended-wear critical Dk/t should be revised upwards to at least 125x10.

Infectious Keratitis After Overnight Orthokeratology in Canada

PURPOSE

To report 3 cases of infectious keratitis related to overnight orthokeratology use.

METHODS

Retrospective case observation.

RESULTS

All 3 patients were using overnight orthokeratology lenses when they presented with unilateral corneal ulcers. The organisms isolated were Acanthamoeba, Pseudomonas aeruginosa, and Serratia marcescens. The clinical presentation and treatment of each case is presented.

CONCLUSIONS

Overnight orthokeratology use may be associated with infectious keratitis despite the use of more oxygen-permeable materials and improved lens design. Patient education with informed consent, appropriate lens care, and meticulous follow-up is important. Because this complication is potentially sight threatening, orthokeratology requires further analysis and evaluation to establish its safety. The cases here are the first few reported cases in North America.

Over-the-Counter Decorative Contact Lenses: Cosmetic or Medical Devices? A Case Series

PURPOSE

To illustrate the implications of the unauthorized sale and unmonitored wearing of decorative cosmetic contact lenses resulting in ocular complications and to determine the prevalence of the use of cosmetic contact lenses obtained from unlicensed providers by adolescents.

METHODS

Observational case report, structured interview, and survey in a retrospective, observational, clinical practice setting. Reported sources of contact lenses were categorized as provider and nonprovider, and associations within the data were reviewed by using a Pearson correlation and chi-square test.

RESULTS

Twelve patients (eight female and four male) were seen urgently for acute eye pain and redness after wearing plano decorative contact lenses. None of the patients had previously worn a contact lens. None of the lenses were dispensed by eye care professionals. Four patients developed blinding infections requiring hospital admission. Causative organisms included staphylococci, Pseudomonas, and acanthamoeba. One patient required a penetrating keratoplasty. One hundred fifty-nine patients were surveyed. Thirty-seven (23%) used decorative contact lenses. Lenses were obtained from an unlicensed provider 51% of the time. Education about lens care and handling was significantly associated with acquiring lenses from licensed providers (R = 0.74, P < 0.0001).

CONCLUSIONS

Colored noncorrective contact lenses are being dispensed without a prescription or fitting from unlicensed vendors. Patients who acquire lenses from unauthorized providers are significantly less likely to be instructed on appropriate lens use and care. Consequently, uninformed lens wearers are experiencing acute vision-threatening infections and inflammation.

Corneal Oxygen Deficiency

OBJECTIVES

To compare the ocular effects of low Dk hydrogel and high Dk silicone hydrogel contact lenses.

METHODS

A review of recent literature was conducted to determine the effects of wearing low and high Dk soft lenses on corneal swelling, vascular response, refractive error and the corneal epithelium.

RESULTS

High Dk silicone hydrogel contact lenses became available for research and clinical practice almost 10 and 5 years ago respectively. During that time many studies have been conducted and it has been demonstrated repeatedly how much improvement there has been to the physiological response of the eye particularly when wearing the lenses on an overnight basis.

CONCLUSIONS

Although silicone hydrogels only constitute about 2% of current wearers, their positive effects on the eye compared with low Dk hydrogel lenses should make them the most dominant lenses in the near future.

Hypoxia increases corneal cell expression of CFTR leading to increased Pseudomonas aeruginosa binding, internalization, and initiation of inflammation

PURPOSE

To investigate the effect of hypoxia-induced molecular responses of corneal epithelial cells on the surface of rabbit and human corneas and corneal cells in culture on interactions with Pseudomonas aeruginosa that may underlie increased susceptibility to keratitis.

METHODS

Organ cultures of rabbit and human corneal tissue, primary rabbit and human corneal cells, and transformed human corneal cells from a patient with cystic fibrosis and the same cell line corrected for expression of wild-type cystic fibrosis transmembrane conductance regulator (CFTR), the cellular receptor for P. aeruginosa, were exposed to hypoxic conditions for 24 to 72 hours. Changes in binding and internalization of P. aeruginosa were measured using cellular association and gentamicin-exclusion assays, and expression of CFTR and activation of NF-kappaB in response to hypoxia were determined by confocal laser microscopy and quantitative measurements of NF-kappaB activation.

RESULTS

Hypoxia induced in a time- and oxygen-concentration-dependent manner increased association and internalization of clinical isolates of P. aeruginosa in all cells tested. Hypoxia increased CFTR expression and NF-kappaB nuclear translocation in rabbit and human cells with wild-type CFTR. Corneal cells lacking CFTR had reduced NF-kappaB activation in response to hypoxia. Hypoxia did not affect the increase in corneal cell CFTR levels or NF-kappaB activation after P. aeruginosa infection.

CONCLUSIONS

Hypoxic conditions on the cornea exacerbate the binding and internalization of P. aeruginosa due to increased levels of CFTR expression and also induce basal NF-kappaB activation. Both of these responses probably exacerbate the effects of P. aeruginosa infection by allowing lower infectious doses of bacteria to induce disease and promote destructive inflammatory responses.

Is Corneal Refractive Therapy a New Modality Whose Time Has Come or Repackaged Orthokeratology Whose Time Has Passed?

I was asked to evaluate corneal refractive therapy (CRT) as an experienced ophthalmologist, who is a corneal specialist. I reviewed the literature and listened to and talked with ophthalmologists, optometrists, and researchers using and studying CRT. I feel that CRT is safe and effective. It offers a nonsurgical option for patients who are not eligible for surgery, particularly because of age, or for those who want to correct myopia for daytime vision but do not want to have surgery or wear a contact lens. CRT can be a valuable option to provide patients in a refractive surgery practice.

A Hyper-Dk Piggyback Contact Lens System for Keratoconus

PURPOSE

To report the fitting of a hyper-Dk piggyback contact lens system in a case of keratoconus.

METHODS

Case report.

RESULTS

A patient with keratoconus, suboptimal visual acuity, corneal neovascularization, and marked conjunctival hyperemia, who was intolerant of rigid gas-permeable contact lenses, was fitted with a novel piggyback contact lens system that incorporated a hyper-oxygen transmissible hydrogel contact lens, on top of which was fitted a hyper-oxygen transmissible rigid gas-permeable lens. This novel contact lens system provided a significant improvement in visual acuity, comfort, and lens wear time. There was a marked reduction in corneal vascularization and ocular hyperemia.

CONCLUSIONS

This hyper-Dk piggyback contact lens system satisfied the ocular and visual requirements of this patient, for whom other nonsurgical options for vision correction had been unsuccessful. This system has potential application in the visual rehabilitation of other cases of corneal irregularity, including unsuccessful refractive surgery, ocular trauma, and keratoplasty. Piggyback contact lens systems require the same level of expertise to fit as basic forms of soft and rigid contact lenses. The hyper-oxygen transmissible lens materials available make these dual-lens systems a viable option for the compromised cornea.

Comparing goblet cell densities in patients wearing disposable hydrogel contact lenses versus silicone hydrogel contact lenses in an extended-wear modality

PURPOSE

The current study evaluates the response of the ocular surface to extended contact lens wear by comparing a new silicone hydrogel lens to an ACUVUE 2 lens.

METHODS

Twenty subjects with an average age of 28 years were randomly assigned to a fitting with ACUVUE 2 or PureVision lenses. Ocular surface assessment by impression cytology was performed at baseline and for the 6 months after initiation of lens wear.

RESULTS

Although goblet cell density significantly increased with wear time, no statistically significant difference was observed between the contact lens groups. The average baseline goblet cell percentages were as follows: ACUVUE 2 group, 1.44; PureVision group, 1.11. The 6-month averages were as follows: ACUVUE 2 group, 3.16; PureVision group, 2.22.

CONCLUSIONS

It appears that silicone hydrogel lenses may be slightly less irritating to the ocular surface than lenses not containing silicone. This could be a promising indicator for successful 30-day continuous wear.

Ocular complications associated with the use of cosmetic contact lenses from unlicensed vendors

PURPOSE

To call attention to the unauthorized sale of cosmetic contact lenses, resulting in ocular complications. DESIGN Observational case report.

METHODS

Retrospective, observational, clinical practice setting.

RESULTS

Six patients (five female and one male) were seen urgently for acute eye pain and redness after wearing cosmetic plano contact lenses. None of the patients had previously worn a contact lens or spectacle correction. None of the lenses were dispensed by eye care professionals. One patient developed pseudomonal keratitis, ultimately requiring penetrating keratoplasty for visual rehabilitation.

CONCLUSIONS

Colored contact lenses are being dispensed without a prescription or fitting from unlicensed vendors, such as cosmetics, convenience, and accessory stores. Lenses are sold individually and without care instructions. Consequently, uninformed lens wearers are experiencing acute, vision-threatening infections and inflammation.