End-of-day assessment of asymptomatic versus highly symptomatic soft contact lens wearers.

PURPOSE: To investigate differences in key clinical parameters between asymptomatic and highly symptomatic soft contact lens (CL) wearers after 14 h of wear. METHODS: In this pilot investigation, Phase 1 identified asymptomatic (CLDEQ-8 score ≤ 7) and highly symptomatic (CLDEQ-8 score ≥ 20) subjects after fitting with nelfilcon A CLs. Phase 2 investigated the following over a single nelfilcon A CL-wearing day (14 ± 2 h): blinking characteristics, tear meniscus height (TMH), non-invasive tear break-up time (NIBUT), tear film osmolarity and eyelid margin staining. Parameters for the two groups were compared using linear mixed models and post-hoc testing. The relationship between comfort scores and the clinical parameters was also investigated. RESULTS: Overall, 161 and 42 subjects were enrolled into Phase 1 and 2, respectively. Twenty-five asymptomatic and 17 symptomatic subjects completed Phase 2. Lower eyelid TMH was decreased after 14 h in symptomatic compared with asymptomatic subjects (least square mean [LSM] difference -0.04 mm, 95% CI: -0.07, -0.01). Osmolarity was lower in symptomatic than in asymptomatic subjects at fitting (LSM difference -9.89, 95% CI: -18.91, -0.86). Upper eyelid margin staining was greater after 14 h in symptomatic than in asymptomatic subjects (LSM difference 0.53, 95% CI: 0.01, 1.05) and greater after 14 h than baseline in the symptomatic group (LSM difference 0.61, 95% CI: 0.16, 1.07). There was a significant relationship between comfort and upper eyelid margin staining (r = -0.40, 95% CI: -0.63, -0.11) and blink rate (r = -0.31, 95% CI: -0.57, -0.003). CONCLUSION: The potential parameters most effective in differentiating asymptomatic from symptomatic wearers were upper eyelid margin staining and lower TMH. The parameter with the strongest relationship to comfort was upper eyelid margin staining, where higher comfort scores were associated with lower levels of staining.

Topical Review: Contact Lens Eye Health and Safety Considerations in Government Policy Development.

SIGNIFICANCE: As new federal or state policies are introduced in the United States to shape the evolving contact lens market, it has never been more important to amplify the importance of patient health and safety during contact lens wear and promote the value of the eye care professional-patient relationship.Within the United States, contact lenses are regulated by the Food and Drug Administration as class II or III medical devices that require additional regulatory and professional oversight to keep consumers safe. The contact lens market and broader eye health landscape are rapidly changing. Recently, the U.S. Federal Trade Commission finalized its 10-year review of the Contact Lens Rule, implementing new policies that will shape the contact lens market in the United States for years to come. The purpose of this clinical perspective was to compile and review key data regarding contact lens-related adverse events, including their economic impact on the health care system, to inform government policy development. Although contact lenses provide many benefits to the wearer, a variety of complications can occur ranging from asymptomatic events or mild discomfort to severe sight-threatening adverse events such as microbial keratitis. Patients who do not routinely visit their eye care professional or do not receive the lenses prescribed to them are at a greater risk of contact lens-related adverse events. Nearly 1 million people in the United States experience ocular infections or inflammation annually, resulting in significant health care costs. The economic burden of contact lens-related microbial keratitis in the United States has been estimated to be approximately $175 million annually. The importance of eye care professional oversight of contact lens wear cannot be emphasized enough to key stakeholders, including lawmakers, government regulators, contact lens manufacturers and distributors, and the broader eye health community.

American Academy of Optometry Microbial Keratitis Think Tank.

SIGNIFICANCE: Think Tank 2019 affirmed that the rate of infection associated with contact lenses has not changed in several decades. Also, there is a trend toward more serious infections associated with Acanthamoeba and fungi. The growing use of contact lenses in children demands our attention with surveillance and case-control studies. PURPOSE: The American Academy of Optometry (AAO) gathered researchers and key opinion leaders from around the world to discuss contact lens-associated microbial keratitis at the 2019 AAO Annual Meeting. METHODS: Experts presented within four sessions. Session 1 covered the epidemiology of microbial keratitis, pathogenesis of Pseudomonas aeruginosa, and the role of lens care systems and storage cases in corneal disease. Session 2 covered nonbacterial forms of keratitis in contact lens wearers. Session 3 covered future needs, challenges, and research questions in relation to microbial keratitis in youth and myopia control, microbiome, antimicrobial surfaces, and genetic susceptibility. Session 4 covered compliance and communication imperatives. RESULTS: The absolute rate of microbial keratitis has remained very consistent for three decades despite new technologies, and extended wear significantly increases the risk. Improved oxygen delivery afforded by silicone hydrogel lenses has not impacted the rates, and although the introduction of daily disposable lenses has minimized the risk of severe disease, there is no consistent evidence that they have altered the overall rate of microbial keratitis. Overnight orthokeratology lenses may increase the risk of microbial keratitis, especially secondary to Acanthamoeba, in children. Compliance remains a concern and a significant risk factor for disease. New insights into host microbiome and genetic susceptibility may uncover new theories. More studies such as case-control designs suited for rare diseases and registries are needed. CONCLUSIONS: The first annual AAO Think Tank acknowledged that the risk of microbial keratitis has not decreased over decades, despite innovation. Important questions and research directions remain.

In Vitro Compatibility of Contact Lenses With Corneal Epithelial Cells.

PURPOSE: To determine the interaction of contact lenses of different materials with corneal epithelial cells grown in tissue culture. METHODS: Two different corneal epithelial cell lines were grown to confluence in culture media. Two hydrogel contact lenses with and without polyvinylpyrrolidone (PVP) {1-DAY ACUVUE MOIST (1-Day ACUVUE [hydrogel lenses]) and a silicone hydrogel contact lens, AIR OPTIX NIGHT & DAY} were removed from their blister packs, washed in phosphate-buffered saline, and applied to the cells. After exposure for 24 hr at 37°C, lenses were removed, and the corneal cells and supernatants processed. Supernatants from the cell assays were used to quantify the amount of 17 different cytokines that were produced using a multiplex bead assay. Cells were stained to assess amount of cell death (apoptosis or necrosis) or stained to determine the level of mitochondrial activity. Stimulants of necrotic death (latex) or apoptotic death (sorbitol) were used as positive controls. RESULTS: Cells produced cytokines during normal growth. Exposure of cells to the hydrogel lenses resulted in only minimal changes to normal production of cytokines, but latex or sorbitol produced the most change. Exposure of the cells to all three lenses caused 4% to 23% reduction in mitochondrial activity, whereas exposure to the positive controls caused 71% to 98% reduction in mitochondrial activity. Exposure of the corneal epithelial cells to contact lenses produced minimal morphological changes, whereas exposure to latex or sorbitol produced significant changes to the human corneal epithelial cell line. CONCLUSIONS: Exposure of corneal epithelial cells to contact lenses had minimal impact on their physiology. There was no difference in epithelial cell responses to hydrogel with or without PVP compared with the silicone hydrogel contact lens.

Lipid Deposition on Contact Lenses when Using Contemporary Care Solutions.

SIGNIFICANCE: There remains only a small amount of data from human studies demonstrating the effect of contact lens/lens care solution combinations on the deposition of lipids. Therefore, information on the degree to which modern materials deposit lipids when used with contemporary care solutions would be valuable. PURPOSE: The present study aims to determine the effect of lens care system combinations on levels of total lipid, cholesterol, and cholesteryl esters extracted from three different contact lenses (CLs) when used with four contemporary care systems. METHODS: Experienced CL wearers were recruited to participate in this study. Combinations of three CLs (etafilcon A [ETA], galyfilcon A [GALY], and senofilcon A [SENO]) and four CL care solutions (Biotrue, ClearCare, OPTI-FREE PureMoist, and RevitaLens Ocutec) were investigated. A total of 791 CLs were analyzed. Subjects were randomized to one lens type and then used all four lens care solutions in random sequence for 10-14 days before the CLs were collected and analyzed for the amount of cholesterol, cholesteryl esters, and total lipids. RESULTS: The mean range of cholesterol recovered across the different care solutions was 0.34-2.77 µg/lens, 3.48-4.29 µg/lens, and 4.75-6.20 µg/lens for ETA, SENO, and GALY lenses, respectively. Use of OPTI-FREE PureMoist with ETA lenses led to a significantly greater amount of cholesterol being recovered when compared to the use of the other solutions with ETA lenses (P < .05). The mean range of cholesteryl esters recovered across different care solutions was 1.31-2.02 µg/lens, 6.43-7.19 µg/lens, and 7.96-10.13 µg/lens for ETA, SENO, and GALY lenses, respectively. There were no differences in the amount of cholesteryl esters and total lipids extracted for a given lens type when used with any of the four care solutions (P > .05). CONCLUSIONS: This study did not demonstrate conclusively that any of the solution/CL combinations were superior to any of the other combinations when the amounts of lipid deposition were compared among the tested lenses.

Impact of Lens Care Solutions on Protein Deposition on Soft Contact Lenses.

PURPOSE: To evaluate the effect of four contemporary lens care solutions on total protein, total lysozyme, and active lysozyme extracted from three contact lens materials. METHODS: Adapted contact lens wearers were recruited at three sites, and all subjects were randomly assigned to daily wear of either etafilcon A, galyfilcon A, or senofilcon A for 2 weeks. Four lens care solutions (Biotrue, OPTI-FREE PureMoist, RevitaLens OcuTec, and ClearCare) were used by each subject in random order with a new pair of lenses after a washout period between solutions of at least 4 days. After 2 weeks of daily wear, contact lenses were collected for analysis. Proteins were extracted from a subset of contact lenses (n = 568) and total protein, total lysozyme, and lysozyme activity were quantified using a modified Bradford assay, an enzyme-linked immunosorbent assay, and a micrococcal assay, respectively. RESULTS: Higher levels of total protein were extracted from etafilcon A when used with Biotrue compared to other solutions (p = 0.0001). There were higher levels of total lysozyme extracted from galyfilcon A lenses when used with PureMoist than with Biotrue or ClearCare (p < 0.006). Higher total lysozyme was extracted from senofilcon A when used with RevitaLens OcuTec compared to Biotrue (p = 0.002). Lower lysozyme activity was recovered from senofilcon A lenses with RevitaLens OcuTec when compared to all other care solutions (all p < 0.004). When Biotrue, PureMoist, or RevitaLens OcuTec were used, higher total lysozyme was extracted from galyfilcon A compared to senofilcon A (p < 0.01). When RevitaLens OcuTec was used, higher levels of active lysozyme were extracted from galyfilcon A compared to senofilcon A (p = 0.02). CONCLUSIONS: The ability of lens care solutions to remove protein from lenses varies depending upon the care solution composition and also the polymeric make-up of the contact lens material.

Microbial Contamination of Contact Lens Storage Cases During Daily Wear Use.

PURPOSE: To evaluate contact lens (CL) storage case contamination when used with four different CL care solutions during daily wear of three different CL materials. METHODS: A parallel, prospective, bilateral, randomized clinical trial (n = 38) was conducted. Subjects were randomly assigned to use one of three CL materials (etafilcon A, senofilcon A, or galyfilcon A) on a daily wear basis. Subsequently, each subject randomly used one of four different CL care solutions (Biotrue, OPTI-FREE PureMoist, RevitaLens OcuTec, and CLEAR CARE) for 2 weeks, along with their respective storage cases. After every 2-week period, their storage cases were collected and the right and left wells of each storage case were randomized for two procedures: (1) microbial enumeration by swabbing the storage case surface and (2) evaluation of biofilm formation (multipurpose solution cases only) using a crystal violet staining assay. RESULTS: More than 80% of storage cases were contaminated when used in conjunction with the four CL care solutions, irrespective of the CL material worn. Storage cases maintained with CLEAR CARE (mean Log colony forming units (CFU)/well ± SD, 2.0 ± 1.0) revealed significantly (p < 0.001) greater levels of contamination, compared to those maintained with Biotrue (1.3 ± 0.8) and RevitaLens OcuTec (1.2 ± 0.8). Predominantly, storage cases were contaminated with Gram-positive bacteria (≥80%). There were significant differences (p = 0.013) for the levels of Gram-negative bacteria recovered from the storage cases maintained with different CL care solutions. Storage cases maintained with OPTI-FREE PureMoist (0.526 ± 0.629) showed significantly higher biofilm formation (p = 0.028) compared to those maintained with Biotrue (0.263 ± 0.197). CONCLUSIONS: Levels of contamination ranged from 0 to 6.4 Log CFU/storage case well, which varied significantly (p < 0.001) between different CL care solutions, and storage case contamination was not modulated by CL materials.

Review of complications associated with contact lenses from unregulated sources of supply.

OBJECTIVE: To review existing studies and case reports regarding complications associated with contact lenses (CLs) from unregulated sources of supply and to identify any relevant trends. METHODS: A systematic literature search was performed to locate publications concerning complications associated with CLs obtained from unregulated sources of supply. RESULTS: A total of 23 articles were identified that represent 70 individual cases. All 8 of the pre-2006 case reports originated from the United States and the United Kingdom, whereas from 2006 onwards, only 2 of the 15 reports came from these locations. Over-the-counter supply accounted for 73% (51/70) of cases, whereas 17% (12/70) were borrowed or shared lenses and 6% (4/70) lenses were obtained through the Internet. Nearly, three quarters of patients (30/42, 71%) waited longer than 48 hours after the onset of symptoms before seeking medical attention; 10 patients waited longer than a week, and 5 longer than a month. Microbial keratitis (MK) was reported in 43 (61%) patients, with permanent damage occurring in 72% (31/43) of patients followed to conclusion. Known risk factors associated for MK were present in all cases irrespective of whether the patients developed MK. CONCLUSIONS: There are various reasons to presume that the unregulated supply of CLs might result in the use of inappropriate lenses, increase the risk of poorer lens hygiene, and militate against the prompt treatment of any consequent complications. There is some indication that the introduction of regulations to control the supply of plano CLs has alleviated the level of complications.

Tear Proteomics of Children and Young Adult Soft Contact Lens, Orthokeratology and Spectacle Wearers - A Pilot Study.

PURPOSE: Contact lens complications occur more often in older teenagers and young adults compared to children. This study explored differences in tear proteomics between children and young adults wearing soft contact lens (SCL), orthokeratology or spectacles for >3 years. METHODS: Twelve children and 12 sex- and correction-matched young adults were enrolled. Tears were collected via Schirmer strips for tear proteomic analysis using mass spectrometry. Proteome Discoverer was used for protein identification. Label-Free Quantitation was generated using Scaffold software; Fisher's Exact tests were used to compare proteins by age and correction groups. Generalized linear models were used to assess differences in overall protein levels by age and correction groups. A secondary analysis of proteins presented in >50% of samples of each group was conducted using the R/Bioconductor limma package. RESULTS: There were 385 proteins present only in young adults while 183 were unique in children. There were 528 unique proteins to SCL, 96 to orthokeratology and 149 to spectacle wearers. Based on Fisher's Exact analyses, 126 proteins were higher in young adults than children (all P < 0.048). Forty-seven protein levels were higher in SCL compared to orthokeratology (all P < 0.01), 33 protein levels were higher in SCL compared to spectacles (all P < 0.01), 15 protein levels were higher in orthokeratology compared to spectacle wearers (all P < 0.01). Based on generalized linear models, young adults had higher overall protein levels than children (P = 0.001), SCL had higher protein levels than spectacle wearers (P < 0.001) but no differences were found between orthokeratology and spectacle wearers (P = 0.79). Based on the secondary analysis, only Antileukoproteinase was higher in the young adult orthokeratology group compared to other groups (P < 0.01). CONCLUSIONS: Tear protein type and abundance differ by age and correction. Further research is needed to understand the effects of contact lens correction in children and young adults on the tear proteome.

Clinical investigation of asmofilcon a silicone hydrogel lenses.

PURPOSE: To investigate the clinical and subjective performance of asmofilcon A, a new third generation silicone hydrogel contact lens during 6-night extended wear (EW) over 6 months. METHODS: A prospective, randomized, single-masked study was conducted. Sixty experienced daily wear soft contact lens wearers were randomly assigned to wear either asmofilcon A or senofilcon A contact lenses bilaterally for 6 months on an EW basis. Evaluations were conducted at contact lens delivery and after 1 week, 4 weeks, 3 and 6 months of EW. RESULTS: Fifty subjects (83%) successfully completed the study. Two subjects experienced adverse events; one unilateral red eye with asmofilcon A and one asymptomatic infiltrate with senofilcon A. There were no significant differences in high or low contrast distance visual acuity between asmofilcon A and senofilcon A; however, low contrast distance visual acuity decreased significantly over time with both contact lens types (p < 0.05). The two lens types did not vary significantly with respect to any of the objective and subjective measures assessed (p > 0.05). Superior palpebral conjunctival injection showed a statistically significant increase over time with both lens types (p < 0.05). Both lens types were rated highly with respect to overall comfort, with subjects reporting 14 or 15 h of comfortable lens wearing time per day at each of the study visits (p > 0.05). Overall satisfaction ratings were also very high at all visits, with median scores of 95 (86 to 99) for asmofilcon A and 90 (85 to 96) for senofilcon A at 6 months (p > 0.05). CONCLUSIONS: Over 6 months of EW, the asmofilcon A contact lens performed in a similar manner to senofilcon A with respect to visual acuity, ocular health, and contact lens performance measures. Longer-term EW studies are required to investigate the changes over time observed with both lens types.

Color vision assessment by Farnsworth lantern: results using alternative pass-fail criteria.

INTRODUCTION: The Farnsworth lantern is used in the United States and Australia to assess pilot applicants who have deficient color vision (DCV). Its efficacy was questioned following a crash in July 2002 because the DCV pilot confused the red and white approach path signals, despite having passed the Farnsworth test. The Farnsworth lights are larger and brighter than many aviation signals and it has a higher pass rate than the lantern tests used in other countries. Moreover, applicants can pass by making no errors on 1 run of 18 lights, which is too small a sample. METHODS: There were 3 runs of the Farnsworth lantern given to 100 male subjects with DCV. The effect on pass rate of changing the number of runs and the pass criterion was assessed. RESULTS: There were 20 subjects who passed the Farnsworth lantern test. Their average error rate over three runs was 3.9%; two had an error rate of 13% and five confused red and white signals, the colors used in approach path signals. One subject passed by having zero errors on run 1 but made 13% errors on the next two runs. If all subjects are given two runs after a practice run, 15% pass if the pass criterion is < or = 1 error and 11% pass if it is zero errors. No subject made red-white color confusions with the zero error pass criterion. CONCLUSIONS: A practice run and two test runs should always be given. The pass criterion should be < or = 1 error in total on the two test runs.

Potential Role of Ocular Microbiome, Host Genotype, Tear Cytokines, and Environmental Factors in Corneal Infiltrative Events in Contact Lens Wearers.

Purpose: The purpose of this study was to explore differences in genotype, ocular surface microbiome, tear inflammatory markers, and environmental and behavioral exposures in soft contact lens (SCL) wearers with and without a history of corneal infiltrative events (CIEs). Methods: Nine SCL wearers with a recent CIE and nine age-, sex-, and SCL material- and modality-matched controls were enrolled. The Contact Lens Risk Survey, slit-lamp examination data, basal tears, conjunctival microbial cultures, and peripheral blood samples were collected. Tear inflammatory mediator concentrations, genomic DNA from swabs, and whole exome sequencing of blood samples were quantified. Results: There were no marked differences in SCL wear behaviors or exposures between case and control subjects. Predominant organisms detected among case and control subjects were Staphylococcus, Propionibacterium, Streptococcus, and Corynebacterium. Marginally higher levels of Neisseria were found in three of nine cases but zero of nine control samples (P = 0.056). A potentially deleterious missense single nucleotide polymorphism (SNP) variant in IL-6 Signal Transducer (IL6ST) was found in seven of eight cases and zero of nine controls (rs2228046; P = 0.03). The concentration of tear IL-6 was significantly higher in cases (4.5 [range, 2.1 to 6.2] pg/mL) versus controls (3.5 [range, 2.5 to 6.6] Pg/mL; = 0.02). Conclusions: Tear IL-6 concentration was higher, and SNP variants were detected in subjects with a history of CIEs compared with healthy controls. The synthesis, signaling, and ocular surface cytokine concentration of IL-6 may be related to susceptibility to CIE. A larger study population is required to further explore relationships between genetic variations, the ocular surface microbiome, inflammatory mediators, and environmental exposures.

Infection control guidelines for optometrists 2007.

Information from peer-reviewed articles, guidelines from professional societies and manufacturers' instructions were considered to determine the risk factors in optometric practice and to make recommendations for disinfection, sterilisation and reprocessing of instrumentation and other equipment used in practice and measures for personal protection. Wherever possible, all practitioners should adopt measures to decrease the risk of transmission of infection, such as single use instruments/equipment, appropriate methods of reprocessing where items are reused, routine employment of standard infection control precautions and application of more rigorous procedures for infected or immuno-suppressed individuals.

Can color vision defective subjects who pass the farnsworth lantern test recognize surface color codes?

INTRODUCTION: The International Civil Aviation Organization requires that pilots be able to distinguish the colors used in air navigation and in particular be able to identify the colors of signal lights. Most national aviation authorities use a lantern test to assess the ability of applicants for a pilot's license who have abnormal color vision to recognize the colors of signal lights. However, color-coding is now widely used in aviation systems other than signal lights. Color is used in tarmac markings, maps, manuals, and electronic flight instrument displays. These color codes can use 10 or more colors, many more than the 3 to 5 used for signal lights. This study investigated whether people with defective color vision (DCV) who pass the Farnsworth lantern test can recognize the main colors used for surface color codes. METHODS: There were 99 subjects with DCV who were tested using the Optec 900 version of the Farnsworth lantern test and also named the colors of a set of 10 surface colors that varied in shape (dots and lines) and size (3 sizes; angular diameters 0.27, 1.0, and 2.4 degrees; angular widths 0.14, 0.27, and 0.50 degrees). A control group of 20 subjects with normal color vision also named the surface colors. RESULTS: Of the DCV subjects, 19% passed the Farnsworth lantern test, of whom 74% made no errors with the surface colors. The other 26% made few errors (up to 5 errors in 120 presentations) and those errors were mostly to confuse red, orange, and brown. The subjects with normal color vision made no errors naming the surface colors. CONCLUSION: Those who pass the Farnsworth lantern test can recognize the colors of a 10-color surface color code with few or no errors. This is because the small (2.9-min arc) stimulus of the lantern test presents a more difficult task than the larger surface colors.

Evaluation of the performance of photochromic spectacle lenses in children and adolescents aged 10 to 15 years.

BACKGROUND: To compare the performance of clear and photochromic spectacle lenses in children and adolescents, with respect to visual acuity and satisfaction with day-to-day activities. METHODS: Fifty full-time spectacle wearers, aged 10 to 15 years, were randomly assigned to wear clear and Transitions photochromic spectacle lenses for two weeks each in a crossover fashion. Subjects were evaluated at screening, lens delivery and two weeks post-delivery. At each visit, distance and near visual acuity (VA, logMAR) were assessed and subjective questionnaires, using Likert scales, were administered. Parents/guardians also completed questionnaires at entry and exit from the study. RESULTS: There were no significant differences in VA between clear and photochromic lenses (p > 0.05) and no difficulties were encountered with completion of the questionnaires. Subjective evaluation of vision in bright sunlight and when playing sport was significantly better with photochromic compared to clear lenses (p < 0.05). There were no significant differences between lens designs in subjective performance indoors, such as in the classroom or when reading (p > 0.05). Forty-three subjects (88 per cent) chose to continue wearing photochromic lenses on conclusion of the trial. Thirty subjects (61 per cent) preferred photochromic over clear lenses due to reasons such as darkening in sunlight, better vision and less squinting in sunlight. Forty-three parents (88 per cent) rated the children's overall experience with photochromic lenses to be favourable or very favourable. CONCLUSION: Photochromic lenses can be successfully prescribed for children and adolescents aged 10 to 15 years. Clear and photochromic lenses were considered to be equivalent for indoor activities; however, photochromic lenses were significantly preferred over clear lenses for outdoor activities. Likert grading scales can be used effectively in questionnaires for children and adolescents and further development of questionnaires for use in clinical trials evaluating lens performance in children is warranted.

The new Richmond HRR pseudoisochromatic test for colour vision is better than the Ishihara test.

AIM: The Hardy-Rand-Rittler (HRR) pseudoisochromatic test for colour vision is highly regarded but has long been out of print. Richmond Products produced a new edition in 2002 that has been re-engineered to rectify shortcomings of the original test. This study is a validation trial of the new test using a larger sample and different criteria of evaluation from those of the previously reported validation study. METHODS: The Richmond HRR test was given to 100 consecutively presenting patients with abnormal colour vision and 50 patients with normal colour vision. Colour vision was diagnosed using the Ishihara test, the Farnsworth D15 test, the Medmont C-100 test and the Type 1 Nagel anomaloscope. RESULTS: The Richmond HRR test has a sensitivity of 1.00 and a specificity of 0.975 when the criterion for failing is two or more errors with the screening plates. Sensitivity and specificity become 0.98 and 1.0, respectively, when the fail criterion is three or more errors. Those with red-green colour vision deficiency were correctly classified as protan or deutan on 86 per cent of occasions, with 11 per cent unclassified and three per cent incorrectly classified. All those graded as having a 'mild' defect by the Richmond HRR test passed the Farnsworth D15 test and had an anomaloscope range of 30 or less. Not all dichromats were classified as 'strong', which was one of the goals of the re-engineering and those graded as 'medium' and 'strong' included dichromats and those who have a mild colour vision deficiency based on the results of the Farnsworth D15 test and the anomaloscope range. CONCLUSIONS: The test is as good as the Ishihara test for detection of the red-green colour vision deficiencies but unlike the Ishihara, also has plates for the detection of the tritan defects. Its classification of protans and deutans is useful but the Medmont C-100 test is better. Those graded as 'mild' by the Richmond HRR test can be regarded as having a mild colour vision defect but a 'medium' or 'strong' grading needs to be interpreted in conjunction with other tests such as the Farnsworth D15 and the anomaloscope. The Richmond HRR test could be the test of choice for clinicians who wish to use a single test for colour vision.

Color vision assessment: fail rates of two versions of the Farnsworth lantern test.

INTRODUCTION: The Farnsworth lantern test has long been used to assess the color vision of those seeking to enter the aviation industry and other occupations that require recognition of signal lights. A new version of the Farnsworth lantern, the Optec 900, is now produced because the original version is no longer manufactured. This paper reports the pass/ fail rates of a production model of the new version compared with an original one. METHODS: There were 100 male subjects with abnormal color vision who were given 3 runs with each lantern test. Their color vision deficiency was diagnosed using a battery of tests including the D15 test and the Nagel anomaloscope. RESULTS: A total of 19% passed the new lantern test compared with 24% for the original Farnsworth using the usual fail criteria. The pass rates become 17% and 21%, respectively, when adjusted for the expected proportions of the types of abnormal color vision. There was agreement between the two lantern tests for 89% of subjects: 8% passed the old Farnsworth and failed the new version, and 3% failed the original Farnsworth and passed the new. There was a practice effect: when one lantern was passed and the other failed, the lantern passed was, with one exception, given second. Both lantern tests passed subjects who made no errors on the first run who subsequently made many errors when given further runs. Only 4% of subjects made no errors on all runs. CONCLUSION: The Optec 900 can be considered equivalent to the Farnsworth lantern and might be preferred because it is slightly more stringent, reducing the risk of passing those who will make errors with signal lights. The practice of passing applicants who make no errors on the first run should be abandoned since 10% of those who pass in this way make many errors when additional runs are given.

The efficacy of Acanthamoeba cyst kill and effects upon contact lenses of a novel ultraviolet lens disinfection system.

PURPOSE: To assess the efficacy of a novel ultraviolet (UV) lens device on the killing of Acanthamoeba cysts and the impact of efficacious doses of UV upon soft contact lens parameter and material characteristics. DESIGN: Prospective, in vitro, experimental study of a device. METHODS: A UV lens device was constructed and used to expose Acanthamoeba cysts to various levels of UV irradiation. Once an efficacious dose, as defined by a greater than 3 log reduction, was determined (130 mJ/cm(2)), 6 soft contact lens materials (etafilcon A, senofilcon A, galyfilcon A, lotrafilcon A, polymacon, and comfilcon A) were exposed to that dose for 30 cycles and tested for visual parameters, mechanical parameters, and cytotoxicity. RESULTS: The UV device produced an average log reduction of over 3.5 log of Acanthamoeba cysts when the lens and solution inside of the inset case was irradiated with 130 mJ per cm(2) of UV or greater. After 30 cycles of 130 mJ per cm(2) UV dose each, no gross changes were observed in mechanical properties or cytotoxicity tests in any soft contact lenses tested. In visual parameters, polymacon and lotrafilcon A exhibited a shift in sphere power and diameter, respectively. CONCLUSIONS: The novel UV lens device was able to provide a marked log reduction to Acanthamoeba cysts, one of the most resistant ocular disease-causing organisms found in lens cases, without a detrimental effect on many lens materials.

Influenza A(H1N1) and infection control guidelines for optometrists.

The emergence of a novel influenza A virus (Influenza A[H1N1]), which has not circulated previously in humans, has led to the first global influenza pandemic in 41 years. Influenza A(H1N1), commonly called 'swine flu', is a novel influenza virus made up of porcine, avian and human genes, and preferentially infects younger people. Although Influenza A(H1N1) does not appear to be likely to cause as many fatalities as previous influenza pandemics, attempts to contain it are necessary because people whose health is already compromised through underlying chronic medical conditions are at risk of death if they contract the virus. In addition, pregnant women who become infected are at increased risk of complications. This paper provides figures on the number of cases of Influenza A(H1N1) and deaths associated with this virus in Australia (using World Health Organization and Australian Government figures) and discusses infection control measures that optometrists should put in place for themselves, their staff and their patients, in the event that there is suspicion of Influenza A(H1N1) infection. Measures include isolating those who display symptoms indicative of influenza, use of surgical masks (P2 [N95]) by the infected person, frequent hand-washing, appropriate cough and sneeze etiquette, disposal of used tissues and rescheduling of non-urgent appointments for those thought to be infected. Any staff members who need to be closer than one metre to the infected person should also use personal protective equipment (for example, surgical masks, goggles or safety spectacles, gowns and gloves). The current evidence indicates that Influenza A(H1N1) should be treated by optometrists as another type of flu. As with other forms of influenza, following basic infection control guidelines will help reduce the spread of infection in optometric practices and within the community.

Using clinical tests of colour vision to predict the ability of colour vision deficient patients to name surface colours.

PURPOSE: To determine the predictive power of commonly used tests for abnormal colour vision to identify patients who can or cannot name surface colours without error. METHODS: The colour vision of 99 subjects with colour vision deficiency (CVD) was assessed using the Ishihara, the Richmond HRR (2002), the Farnsworth D15, the Medmont C100 and the Nagel anomaloscope. They named 10 surface colours (red, orange, brown, yellow, green, blue, purple, white, grey and black), which were presented in two shapes (lines and dots) and three sizes. The surface colours were also named by an age-matched group of 20 subjects with normal colour vision. The performance of the clinical tests to predict the CVD subjects who made no colour naming errors and those who made errors is expressed in terms of the predictive value of a pass P((P)) and the predictive value of a fail P((F)). RESULTS: The P((P)) values of the tests were between 0.59 and 0.70 and P((F)) values were between 0.77 and 1.00. CONCLUSIONS: A 'mild' classification with the Richmond HRR test, especially if no more than two errors are made on the HRR diagnostic plates, identifies patients with abnormal colour vision who are able to name surface colour codes without error or only the occasional error. A pass of the Farnsworth D15 test identifies patients who will make no or few (up to 6%) errors with a 10 colour code, but who will be able to name the colours of a seven colour code that does not include orange, brown and purple. If protans are excluded, the predictive value for a pass P((P)) for the Farnsworth D15 is improved from 0.59 to 0.70. The anomaloscope is not an especially good predictor of those who can recognise surface colour codes. However, an anomaloscope range >35 units identifies those who have difficulty in recognising surface colour codes, as does a fail at the Farnsworth D15 test.