Disinfection of Goldmann tonometers after contamination with hepatitis C virus

Goldmann Applanation Tonometry: Comparison of Intraocular Pressure Values Obtained with Disposable Tip and Conventional Applanation Prism in the Population without Clinical Signs of Glaucoma

Aim

Comparing intraocular pressure (IOP) measurements using Goldmann applanation prism and TonoSafe® in the population without signs of glaucoma.

Material and methods

Patients with no ocular pathologies, except ametropia (until ± 4 D) or IOP of <30 mm Hg without signs of glaucoma by optic disc structural analysis by fundus biomicroscopy. The IOP was measured sequentially using the traditional cone and the TonoSafe®, according to a randomization list to determine which device would be used first. The measurements from the right and left eyes were compared separately. Since there was no statistical difference, both eyes were considered in this study.

Results

A total of 385 eyes of 194 patients with a mean age of 66.4 ± 11.2 years old were included. The mean IOP with conventional prism was 14.2 ± 3.6 and 14.3 ± 3.6 mm Hg with TonoSafe®. Differences were not statistically significant by the Wilcoxon test (p = 0.3). The median was 14.0 mm Hg for both groups. The mean difference between measurements was 0.04 mm Hg, with the median equal to zero. There was no statistical difference in IOP readings according to which device was the first measurement.

Conclusion

No statistical difference was found in IOP was measured with conventional prism or TonoSafe® in the population without signs of glaucoma.

Clinical significance

The data provided by our study support the efficacy and safety of the disposable tonometer compared to the Goldman tonometer in measuring IOP in patients without glaucoma.

How to cite this article

Soares PHA, Santos RDO, Filho CRADM, et al. Goldmann Applanation Tonometry: Comparison of Intraocular Pressure Values Obtained with Disposable Tip and Conventional Applanation Prism in the Population without Clinical Signs of Glaucoma. J Curr Glaucoma Pract 2023;17(2):75-78.

Semiautomated disinfection of ophthalmic contact lenses

The ophthalmic lenses that come in contact with the eyes pose a high risk for the transmission of bacterial and viral infections in eye clinics. Disinfecting these lenses does not happen stringently in a busy practice. We describe a novel method of disinfecting ophthalmic contact lenses using a semiautomated lens disinfector equipment, semiautomated lens disinfector. The equipment has motors to pump in and pump out water and disinfecting solution into a reservoir bath. The used ophthalmic lenses will be placed in a tray that partially dips into the bath for disinfection. Microbiology tests that were done to check the quality of the disinfection cycle showed good outcomes. Disinfection of ophthalmic contact lenses with the new equipment appeared to effectively eliminate contaminant microorganisms. This equipment can be used in busy ophthalmic clinics to alleviate the chances of cross-infection.

Review of Hygiene and Disinfection Recommendations for Outpatient Glaucoma Care: A COVID Era Update

This review focuses on best practices and recommendations for hygiene and disinfection to limit exposure and transmission of infection in outpatient glaucoma clinics during the current COVID-19 pandemic.

A Systematic Review Regarding Tonometry and the Transmission of Infectious Diseases

Tonometry has been identified as a common method for measuring the intraocular pressure in patients. The direct contact between the tonometer and the eye may contribute to the risk of cross infection, especially of viral particles, from one patient to another. A systematic review was undertaken to address the likelihood of human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus, and prion diseases transmission through the use of tonometers. Additionally, a comparison of the current tonometer disinfection methods is provided to assist with identifying which technique effectively reduces the risk of disease transmission. An electronic literature search was conducted using the following databases: Web of Science, EMBASE, CINAHL, SCOPUS, Biosis Previews, Cochrane Library, PubMed, and Google Scholar. Dissertation indexes were also searched, and these included: Dissertations and Abstracts, and Dissertations and Abstracts - UK/Ireland. Additionally, the Clinicaltrials.gov trial registry was searched to identify any other relevant literature. Two independent reviewers critically appraised the articles retrieved through the literature search. In total, 11 unique studies were deemed relevant for this systematic review. The available evidence demonstrated that the use of tonometers contributes to the transmission of these infectious diseases in vitro. The results also demonstrated variability in determining the most effective tonometer sterilization technique against these infectious diseases in vitro. There was limited evidence available regarding the transmission of HIV, hepatitis B, hepatitis C, and prion diseases through the use of tonometers. Additionally, due to the variability regarding the most effective sterilization techniques, it is difficult to identify which sterilization technique is most effective or adequately effective against these infectious diseases. Future research studies regarding infectious disease transmission through tonometry and sterilization techniques should be completed to more adequately inform infectious disease control guidelines.

Infection control guidelines for optometrists 2016

BACKGROUND

This paper provides an updated version of the paper: Infection control guidelines for optometrists 2007.

METHODS

Information from peer-reviewed journal articles, guidelines from professional societies, and government health department and other websites and instructions from equipment manufacturers were considered in determining infection risk factors in optometric practice. They were used to revise the recommendations on disinfection, sterilisation and reprocessing procedures for instrumentation and other equipment used in optometric practice as well as personal infection control measures to be undertaken by staff.

RESULTS AND CONCLUSIONS

Optometrists and optometric practice staff should adopt measures to minimise the risk of transmission of infection. These include appropriate hand-washing, staff vaccinations, single use instruments/equipment, appropriate disposal of waste, appropriate methods of reprocessing where items are reused, routine employment of standard infection control precautions and application of more rigorous procedures for individuals who are known to be infected or immuno-suppressed. Information provided to patients regarding infection control procedures in topical drug administration, contact lens wear and use of eye make-up are additional considerations for optometrists.

A systematic review and cost-effectiveness analysis of tonometer disinfection methods

OBJECTIVE

The Goldmann applanation tonometer presents the problem of being one of the most widely used pieces of equipment in the ophthalmic clinic and a known risk factor for the transmission of epidemic keratoconjunctivitis (EKC). The purpose of this review is to assess the effectiveness of 3 methods of disinfection: alcohol swabs, immersion in peroxide, and the use of disposable prisms. An economic evaluation is undertaken to assess the cost-effectiveness of the 3 alternatives. In doing so, we contribute an evidence-based overview of the issue at an opportune time, because several jurisdictions are developing protocols regarding tonometer tip disinfection.

DESIGN

Systematic review and cost-effectiveness analysis.

METHODS

A comprehensive literature review was undertaken with a librarian, comprising searches of 6 electronic databases and hand searches of the grey literature. A 3-level screening process was undertaken by 2 reviewers according to prespecified inclusion and exclusion criteria. Values from included papers were used to inform a cost-effectiveness analysis undertaken using a decision tree model implemented in TreeAge. The analysis was undertaken from the hospital perspective and included all equipment and labour costs.

RESULTS

Synthesis of in vitro data indicates that all 3 methods are plausible methods of disinfection with a 64% reduction in log growth of EKC when peroxide is used compared with alcohol swabs. The incremental cost-effective ratios from the cost-effectiveness analysis were $12,000/case averted using peroxide and $61,000/case averted with Tonosafe as compared with alcohol.

CONCLUSIONS

Assuming clinical infection rates match in vitro disinfection data, the cost of bleach is high and the cost of Tonosafe is unacceptably high to reduce 1 potential case of adenoviral keratoconjunctivitis.

Efficacy of detergent and water versus bleach for disinfection of direct contact ophthalmic lenses

PURPOSE

Although manufacturers recommend cleaning ophthalmic lenses with detergent and water and then with a specific disinfectant, disinfectants are rarely used in ophthalmic practices. The aim of this pilot study was to evaluate the efficacy of detergent and water versus that of bleach, a recommended disinfectant, to eliminate common ocular bacteria and viruses from ophthalmic lenses.

METHODS

Three bacterial strains (Staphylococcus epidermidis, Corynebacterium straitum, and methicillin-resistant Staphylococcus aureus and 2 viral strains (adenovirus and herpes simplex virus [HSV] type-1) were individually inoculated onto 20 gonioscopy and laser lenses. The lenses were washed with detergent and water and then disinfected with 10% bleach. All the lenses were cultured after inoculation, after washing with detergent and water, and after disinfecting with the bleach. Bacterial cultures in thioglycollate broth were observed for 3 weeks, and viral cultures were observed for 2 weeks. The presence of viruses was also detected by multiplex polymerase chain reaction (PCR).

RESULTS

All 20 lenses inoculated with S. epidermidis, C. straitum, adenovirus, and HSV-1 showed growth after inoculation but no growth after washing with detergent/water and after disinfecting with the bleach. All lenses showed positive HSV and adenovirus PCR results after inoculation and negative PCR results after washing with detergent/water and after disinfecting with bleach. All methicillin-resistant S. aureus-contaminated lenses showed growth after inoculation and no growth after washing with detergent and water. However, 1 lens showed positive growth after disinfecting with bleach.

CONCLUSIONS

Cleaning with detergent and water seemed to effectively eliminate bacteria and viruses from the surface of contaminated ophthalmic lenses. Further studies are warranted to design practical disinfection protocols that minimize lens damage.

The effects of autobiographic sexual memory recall on the sexual response of sexually functional men

In this experimental study, we investigated how recalling positive, negative, and affectively neutral autobiographic sexual experiences in their personal history affected the current sexual response of sexually functional male volunteers. Based on an attentional-capacity account of sexual arousal, we predicted that affectively charged autobiographic sexual memory recall, both with negative and positive valence, would negatively impact genital arousal, compared to recalling affectively neutral sexual experiences. We expected that subjective sexual arousal would not be differentially affected by emotional memory valence. We measured subjective and genital response to erotic video fragments in sexually functional volunteers (N = 24) in a within-subjects, repeated-measures design. For the memory manipulation, participants received instructions to visualize and mentally re-experience positive, negative, and neutral sexual episodes from autobiographic memory. Memory instructions were found to result in the expected affective states. As predicted, compared to recalling neutral memory, mean genital response was significantly lower during recalling positive and negative memory. However, contrary to prediction, subjective sexual arousal was affected, when multilevel analysis was performed, including a time effect. The implications of the findings were discussed with respect to the advancement of theory and therapeutic intervention.

Reliability of tonosafe disposable tonometer prisms: clinical implications from the Veterans Affairs Boston Healthcare System Quality Assurance Study

PURPOSE

Given the Veterans Affairs Boston Healthcare System's recent introduction of single-use Tonosafe disposable tonometer prisms as an alternative to Goldmann applanation tonometers (GATs), this study had two aims: to conduct a large-scale quality assurance trial to assess the reliability of intraocular pressure (IOP) measurements of the Tonosafe disposable tonometer compared with GAT, particularly at extremes of pressure; to evaluate the suitability of Tonosafe disposable tonometer prisms as an acceptable substitute for GATs and for clinic-wide implementation in an academic tertiary referral setting.

METHODS

Ophthalmology resident physicians measured the IOPs of patients in general and specialty eye clinics with the Tonosafe disposable tonometer and GAT. Tonosafe test-retest reliability data were also collected. A retrospective review of patient charts and data analysis were performed to determine the reliability of measurements.

RESULTS

The IOPs of 652 eyes (326 patients) were measured with both GAT and Tonosafe, with a range of 3-34 mm Hg. Linear regression analysis showed R=0.93, slope=0.91, both of which supported the proposed hypothesis, and the y-intercept=-1.05 was significantly different from the hypothesized value. The Tonosafe test-retest repeatability (40 eyes of 40 patients), r=0.977, was very high, which was further supported by linear regression slope=0.993, y-intercept=0.118, and a Tonosafe repeatability coefficient of 2.06, similar to GAT repeatability.

CONCLUSIONS

The IOP measurements by Tonosafe disposable prisms correlated closely with Goldmann measurements, with similar repeated measurement variability to GAT. This suggests that the Tonosafe is an acceptable substitute for GAT to measure IOP in ophthalmology clinic settings.

Minimal cross-infection risk through Icare rebound tonometer probes: a useful tool for IOP-screenings in developing countries

AIMS

Recently, a new rebound tonometer has been introduced into the market, which might be useful for glaucoma screenings in developing countries. Disposable probes, that are potentially reusable, are recommended by the manufacturer. Our study aimed to address the question of microbial transmission risks if the probes are reused.

METHODS

IOP measurements were obtained from 100 healthy eyes. The used probes were inoculated on broth and culture media. In addition, 10 probes were analyzed using environmental scanning electron microscopy in saturated hydrogen-steam atmosphere after usage and wipe disinfection technique with Sekusept 4% solution or Isopropanol 70%.

RESULTS

No bacterial or fungal growth could be detected in any of the inoculated agar plates or broth tubes. No microorganisms, clumps of cells, or single intact epithelium cells were detected in any of the probes using environmental scanning electron microscopy. Cell debris was detected on seven probes; three probes were completely free of any residual cell elements.

CONCLUSION

Transmission of possibly infective material through reused probes is significantly less than for reusable Goldmann probes if the same sterilization protocols are applied. Re-usage of the probes appears safe and is helpful in avoiding unnecessary costs.

Tonometer prism sterilisation: a local and UK national survey

PURPOSE

First to audit local adherence to a protocol of use of an alcohol wipe for each tonometry, and secondly to assess current practice nationally in the UK.

METHOD

The audit was carried out at two units: The West Kent Eye Centre at the Princess Royal University Hospital (Orpington, UK) and Queen Mary's Hospital (Sidcup, UK). The standard set for this audit was 100% sterilisation. During a 1-week period in November 2005, the number of alcohol wipes was counted in each consultation room after outpatient clinics, with the doctors being assessed blind to the survey. The number of Goldman applanation tonometry intra-ocular pressures recorded by each clinician was counted by inspection of the medical records of patients seen. Secondly, departments listed in the UK Directory of Training Posts were contacted by telephone and the senior nurse was interviewed. They were asked directly about their department's tonometer prism sterilisation and management.

RESULTS

The local audit showed only 54% of tonometry measurements were associated with sterilisation using an alcohol-impregnated wipe. The national survey included 140 of the 152 UK training departments. Thirty-three (23.6%) departments used disposable tonometer prisms routinely. The remaining 107 (76.4%) used non-disposable prisms. Eighty-five (60.7%) departments provided sodium hypochlorite for prism sterilisation, with 69 (81.2%) of these departments providing more than one prism/clinician to allow full exposure to the disinfectant. Twenty-two (15.7%) departments used alcohol wipes. Only 8 (7.5%) of the 107 departments using non-disposable prisms tracked these prisms, despite Royal College of Ophthalmologists guidelines that they should be. These same 8 (7.5%) departments replaced the non-disposable prisms as per manufacturer guidelines. 19.3% of charge nurses were aware of a policy for tonometry in patients with, or at risk of, prion disease.

CONCLUSIONS

This study highlights that sterilisation of tonometer prisms was inconsistent in a local audit. Nationally, practices were varied. The majority of ophthalmology departments continued to use non-disposable tonometer prisms, but few seemed aware of the Royal College of Ophthalmologists' recommendation that disposable prisms are used in patients at risk of prion disease, and few track tonometer heads or replace them according to manufacturers guidelines. Use of disposable tonometer prisms would seem to reduce concerns about sterilisation, as well as prevent spread of common pathogens.

Tonometer disinfection practice in the United Kingdom: A national survey

PURPOSE

To assess current tonometer disinfection practice in the UK, and compare with published recommendations.

METHODS

Every ophthalmology unit with training recognition in the UK was contacted (n=155). A senior nurse at each institution completed a telephone questionnaire regarding local tonometer disinfection practice.

RESULTS

The response rate was 100%. Thirty-five units (23%) reported exclusive use of disposable tonometer heads and were excluded from further analysis. One hundred and twenty units (77%) used either reusable or a combination of reusable and disposable tonometer heads. Where reusable heads were used, 80 units (67%) immersed them in a chlorine-based solution such as sodium hypochlorite or sodium dichloroisocyanurate. Others used isopropyl alcohol (18 units), hydrogen peroxide (12 units), chloramine (5 units), chlorhexidine (4 units) and peracetic acid (1 unit). Where a chlorine-based agent was used, the concentration of available chlorine ranged from 125 to 30 000 p.p.m., with 50 units (63%) using a concentration of less than 5 000 p.p.m. (i.e., inadequate based on published recommendations). Where the tonometer head was immersed in disinfectant between patients (n=101), 29 units (29%) provided just one tonometer head per practitioner, making adequate soak time between patients unlikely. Every unit replenished the disinfectant at least daily, deemed sufficient for most agents. However, hydrogen peroxide solutions should be replenished twice daily, which did not take place in nine units.

CONCLUSION

This survey reveals disparity between current tonometer disinfection practice and published international recommendations, with some institutions using practices that may render patients susceptible to transmissible infection.

The effects of increasing neutral distraction on sexual responding of women with and without sexual problems

This study examined the influence of distraction on genital and subjective sexual responses of women with (N=20) and without (N=21) sexual problems. Female-produced erotic film fragments were presented to induce sexual response and a vaginal photoplethysmograph was used to measure genital sexual responding. Subjective sexual arousal was assessed in real time using a rotating button and, retrospectively, with visual analogue scales. Distraction load was manipulated through different verbal instructions on how to deal with pairs of digits. The results revealed an equally strong impeding effect of distraction on genital sexual responses and on subjective sexual responses when these were measured retrospectively in women with and without sexual problems. However, distraction did not affect subjective sexual responses when these were measured in real time. The implications of the finding that distraction equally affects women with and without sexual problems are discussed.

Tonometers and infectious risk: myth or reality? Efficacy of different disinfection regimens on tonometer tips

PURPOSE

To evaluate the adequacy of common disinfection regimens for disposable tonometer tips and assess if disinfection of reusable prisms or the use of disposable tips is preferable.

METHODS

We used disposable tonometer tips, using the same material and tip diameter of standard Goldmann tonometer prism. Strains of Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilisand Candida albicanswere tested according to the European standard guidelines for disinfectants test. Antimicrobial effectiveness of the following disinfection practices has been assessed: dry wipe, Minuten wipes (Alpro), soaking in 3% hydrogen peroxide, 0.5% benzalkonium chloride, and 0.5% Pantasept for 1, 5, and 15 min. All tests have been performed three times and all conditions tested in duplicate.

RESULTS

Dry wiping and 1 min soak in 3% hydrogen peroxide were ineffective on all microrganisms. Minuten wipes, 1 min soak in 0.5% benzalkonium chloride or 3% hydrogen peroxide were ineffective on B. subtilis. 0.5% Pantasept soak was effective in 1 min for all microrganisms tested, whereas 3% hydrogen peroxide and 0.5% benzalkonium chloride soaks were effective when performed for at least 5 min. B. subtiliswas the most resistant organism to disinfectant regimes at 1 min time.

CONCLUSIONS

Results of our study demonstrate a relative disinfection efficacy for the different evaluated regimens, provided that correct exposure times are adopted for the chosen disinfectants, a condition difficult to ensure in a busy clinic setting. We conclude that disposable prism tonometry provides a safe alternative to Goldmann tonometry.

A comparison of clinical performance between disposable and Goldmann tonometers

PURPOSE

Applanation tonometry as performed in routine clinical practice is a significant potential vehicle for cross-infection particularly in an emergency eye care setting. The aim of this study is to evaluate the accuracy and reliability of three single-use devices (Tonoshield, Tonosafe, Tonojet) as an alternative to standard Goldmann prisms in an emergency eye department.

METHODS

All patients attending the eye casualty at the Manchester Royal Eye Hospital for a period of 4 months who required intraocular pressure measurement were eligible for this prospective study. Exclusion criteria were: age below 18 years, corneal anomalies that might affect measurement, and refusal to participate. After taking informed consent, the patient was examined by one experienced nurse practitioner, who measured the intraocular pressure three times. In the first part of the study, we compared the standard Goldmann prism vsTonoshield and Tonosafe prisms, while for the second part of the study we used standard Goldmann, Tonosafe, and Tonojet prisms. Agreement and repeatability tests were carried out on separate samples.

RESULTS

Tonosafe and Tonojet correlated well with standard Goldmann tonometry (P<0.001), while the measurements obtained with Tonoshield were higher, especially for raised intraocular pressure measurements. Tonojet and Tonosafe measurements were more reproducible than Tonoshield measurements.

CONCLUSIONS

This study shows that Tonosafe and Tonojet are accurate and reliable alternatives to standard Goldmann tonometry.

Accuracy of the Tonosafe disposable tonometer head compared to the Goldmann tonometer alone

PURPOSE

To assess the accuracy of the Tonosafe disposable prism tonometer head via a randomised controlled prospective trial.

METHODS

The intraocular pressure (IOP) of 69 patients (31 men, 38 women) involving 137 eyes was measured using both the Tonosafe disposable and the Goldmann tono-meter head. The average age of patients was 66.5 years (range 23-93 years). The two examiners (PM and SL) who performed tonometry were masked while a separate observer read the IOP measurements. The order was randomised between Tonosafe and Goldmann devices. The minimum interval between the two measurements was 15 min. Patients with corneal and external diseases were excluded from the study.

RESULTS

The mean IOP using the Goldmann tonometer head was 17.44 +/- 4.97 mmHg. The mean IOP using the Tonosafe disposable head was 17.58 +/- 5.03 mmHg. The mean difference was 0.14 +/- 1.73 mmHg (95% CI -0.44, 0.16, P= 0.36). Subgroup analysis on eyes with IOP > 21 mmHg showed the Tonosafe disposable head was on average 0.15 +/- 2.40 mmHg higher than the Goldmann tonometer head. There was a high level of correlation between the IOPs obtained with the Goldmann and Tonosafe heads. Pearson's coefficient of correlation was 0.94 (P < 0.0001).

CONCLUSION

The Tonosafe disposable prism head was found to be accurate in IOP measurement, even in the higher range.