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PURPOSE: To investigate gaze and behavioural metrics at different viewing distances with multifocal contact lenses (MFCLs), single vision contact lenses (SVCLs) and progressive addition lenses (PALs). METHODS: Fifteen presbyopic contact lens wearers participated over five separate study visits. At each visit, participants were randomly assigned to wear one of five refractive corrections: habitual PAL spectacles, delefilcon A (Alcon Inc.) MFCLs and three separate pairs of delefilcon A single vision lenses worn as distance, intermediate and near corrections. Participants wore a Pupil Core headset to record eye and head movements while performing three visual tasks: reading, visual search and scene observation. Data were investigated using linear regression and post-hoc testing. Parameters of interest included gaze (fixation duration, head movement) and behavioural (reading speed, reading accuracy, visual search time) metrics. RESULTS: Reading speed in SVCLs was significantly faster than in MFCLs and PAL spectacles (F = 16.3, p < 0.0001). Refractive correction worn did not influence visual search times (F = 0.16, p = 0.85). Fixation duration was significantly affected by the type of visual task (F = 60.2, p < 0.001), and an interaction effect was observed between viewing distance and refractive correction (F = 4.3, p = 0.002). There was significantly more horizontal and vertical head movement (F = 3.2, p = 0.01 and F = 3.3, p = 0.01, respectively) during visual search tasks when wearing PAL spectacles compared to SVCLs or MFCLs. CONCLUSION: This work showed that the type of refractive correction affects behavioural metrics such as reading speed and gaze behaviour by affecting horizontal and vertical head movements. The findings of this study suggest that under certain conditions, wearers of MFCLs make fewer head movements compared to PAL spectacles. Gaze behaviour metrics offer a new approach to compare and understand contact lens and spectacle performance, with potential applications including peripheral optical designs for myopia management.
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Lentes de Contato , Óculos , Fixação Ocular , Presbiopia , Leitura , Refração Ocular , Acuidade Visual , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Movimentos Oculares/fisiologia , Fixação Ocular/fisiologia , Movimentos da Cabeça/fisiologia , Presbiopia/fisiopatologia , Presbiopia/terapia , Refração Ocular/fisiologia , Acuidade Visual/fisiologia , Estudos Cross-Over , Estudos ProspectivosRESUMO
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.
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Piscadela , Lentes de Contato Hidrofílicas , Lágrimas , Humanos , Lentes de Contato Hidrofílicas/efeitos adversos , Masculino , Feminino , Adulto , Lágrimas/metabolismo , Lágrimas/fisiologia , Projetos Piloto , Piscadela/fisiologia , Adulto Jovem , Concentração Osmolar , Síndromes do Olho Seco/diagnóstico , Síndromes do Olho Seco/etiologia , Síndromes do Olho Seco/fisiopatologia , PálpebrasRESUMO
PURPOSE: To investigate whether there is a measurable change in meibomian gland morphological characteristics over the course of a day (12 h) and over a month. METHODS: The study enrolled 15 participants who attended a total of 11 study visits spanning a 5-week period. To assess diurnal changes in meibomian glands, seven visits were conducted on a single day, each 2 h apart. For monthly assessment, participants attended an additional visit at the same time of the day every week for three consecutive weeks. Meibography using the LipiView® II system was performed at each visit, and meibomian gland morphological parameters were calculated using custom semi-automated software. Specifically, six central glands were analysed for gland length ratio, gland width, gland area, gland intensity and gland tortuosity. RESULTS: The average meibomian gland morphological metrics did not exhibit significant changes during the course of a day or over a month. Nonetheless, certain individual gland metrics demonstrated notable variation over time, both diurnally and monthly. Specifically, meibomian gland length ratio, area, width and tortuosity exhibited significant changes both diurnally and monthly when assessed on a gland-by-gland basis. CONCLUSIONS: Meibomian glands demonstrated measurable structural change over short periods of time (hours and days). These results have implications for innovation in gland imaging and for developing precision monitoring of gland structure to assess meibomian gland health more accurately.
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Glândulas Tarsais , Humanos , Glândulas Tarsais/diagnóstico por imagem , Glândulas Tarsais/anatomia & histologia , Projetos Piloto , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , Idoso , Disfunção da Glândula Tarsal/diagnóstico , Disfunção da Glândula Tarsal/diagnóstico por imagem , Lágrimas/fisiologia , Ritmo Circadiano/fisiologia , Fatores de TempoRESUMO
PURPOSE: Development and validation of a non-invasive imaging system to capture spontaneous blinking and characterise blink dynamics using a custom image analysis algorithm. METHODS: A pilot study investigated the influence of illumination type on blink dynamics. Spontaneous blinking was recorded in eight subjects using a high-speed camera under two illumination conditions: white light and infrared. Custom semi-automated software assessed palpebral aperture height (PAH), blink rate, blink speed, blink completeness and blink duration. The main clinical study compared two different image analysis techniques. Spontaneous blinking was recorded in 20 subjects using a high-speed infrared camera. Blink speed and duration were determined using two techniques: manual tracking and semi-automated tracking. Agreement between the two techniques was assessed using Bland-Altman analysis. Coefficients of repeatability (COR) were calculated for the semi-automated technique. RESULTS: There were significant differences between white light and infrared illumination for PAH (p < 0.0001), blink rate (p = 0.04), closing speed (p = 0.009), opening speed (p < 0.0001) and blink duration (p = 0.0003). The mean differences (95% limits of agreement) between the two techniques were 0.6 mm s-1 (-15.9 to 17.0) closing speed, 1.5 mm s-1 (-6.8 to 9.8) opening speed, 2.4 ms (-6.8 to 11.5) closed phase duration and 5.0 ms (-19.4 to 29.3) total blink duration. COR values were 10.1 mm s-1 closing speed, 3.7 mm s-1 opening speed, 6.7 ms closed phase duration and 11.2 ms total blink duration. CONCLUSIONS: This study has shown that spontaneous blinking can be characterised using a non-invasive imaging system. The semi-automated analysis provides a rapid characterisation of blink dynamics, allowing its application in large-scale trials in a number of clinical areas.
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Piscadela/fisiologia , Diagnóstico por Imagem/métodos , Pálpebras/fisiologia , Processamento de Imagem Assistida por Computador/instrumentação , Software , Adulto , Feminino , Humanos , Masculino , Projetos Piloto , Gravação em VídeoRESUMO
Purpose: To develop and evaluate a custom imaging system to provide high-resolution, wide depth-of-field, reflection-free, multispectral infrared (IR) imaging of the Meibomian glands. Methods: Lower eyelids of 15 volunteers were everted to obtain multispectral images of the Meibomian glands with custom imaging setup. Photographs were captured at 10 different ISO settings (from underexposure to overexposure) and using nine IR imaging filters (ranging from 600 nm to 1000 nm in 50-nm steps). Meibomian gland contrast (simple and Michelson) was calculated for the images to choose an optimal wavelength for Meibomian gland imaging and to determine differences in contrast across individuals. Results: The overall linear regression model showed a significant effect of wavelength on Meibomian gland contrast (Simple contrast: F = 7.24, P < 0.0001; Michelson contrast: F = 7.19, P < 0.0001). There was a significant negative correlation between Meibomian gland contrast and Meibomian gland depth for 750-nm IR filter (ρs= -0.579; P = 0.026). Conclusions: Meibomian gland contrast varies across individuals and depends on Meibomian gland depth. IR filter of 750 nm is the optimal choice for Meibomian gland imaging because it provides images of greatest contrast. Translational Relevance: This study adds to our understanding of Meibomian gland imaging. It has successfully demonstrated that Meibomian glands that are deeper in the tarsal plate require longer wavelengths for imaging.
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Glândulas Tarsais , Humanos , Glândulas Tarsais/diagnóstico por imagemRESUMO
Purpose: To develop and evaluate a deep learning algorithm for Meibomian gland characteristics calculation. Design: Evaluation of diagnostic technology. Subjects: A total of 1616 meibography images of both the upper (697) and lower (919) eyelids from a total of 282 individuals. Methods: Images were collected using the LipiView II device. All the provided data were split into 3 sets: the training, validation, and test sets. Data partitions used proportions of 70/10/20% and included data from 2 optometry settings. Each set was separately partitioned with these proportions, resulting in a balanced distribution of data from both settings. The images were divided based on patient identifiers, such that all images collected for one participant could end up only in one set. The labeled images were used to train a deep learning model, which was subsequently used for Meibomian gland segmentation. The model was then applied to calculate individual Meibomian gland metrics. Interreader agreement and agreement between manual and automated methods for Meibomian gland segmentation were also carried out to assess the accuracy of the automated approach. Main Outcome Measures: Meibomian gland metrics, including length ratio, area, tortuosity, intensity, and width, were measured. Additionally, the performance of the automated algorithms was evaluated using the aggregated Jaccard index. Results: The proposed semantic segmentation-based approach achieved average aggregated Jaccard index of mean 0.4718 (95% confidence interval [CI], 0.4680-0.4771) for the 'gland' class and a mean of 0.8470 (95% CI, 0.8432-0.8508) for the 'eyelid' class. The result for object detection-based approach was a mean of 0.4476 (95% CI, 0.4426-0.4533). Both artificial intelligence-based algorithms underestimated area, length ratio, tortuosity, widthmean, widthmedian, width10th, and width90th. Meibomian gland intensity was overestimated by both algorithms compared with the manual approach. The object detection-based algorithm seems to be as reliable as the manual approach only for Meibomian gland width10th calculation. Conclusions: The proposed approach can successfully segment Meibomian glands; however, to overcome problems with gland overlap and lack of image sharpness, the proposed method requires further development. The study presents another approach to utilizing automated, artificial intelligence-based methods in Meibomian gland health assessment that may assist clinicians in the diagnosis, treatment, and management of Meibomian gland dysfunction. Financial Disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article.
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CLINICAL RELEVANCE: Evaluating how Meibomian glands can change in appearance has the potential to advance the understanding of Meibomian gland health and may lead to enhanced diagnosis and therapy. BACKGROUND: This work aimed to investigate Meibomian gland appearance after therapeutic Meibomian gland expression. METHODS: Fifteen subjects attended three study visits over a two-week period. Meibography was performed before and after therapeutic Meibomian gland expression, the following day, and 2 weeks after expression. Six central glands were used to calculate Meibomian gland morphological parameters such as gland length ratio, gland width, gland area, gland tortuosity, and gland contrast. A custom semi-automated image analysis software was used to calculate Meibomian gland metrics. Furthermore, a high-resolution imaging system was developed to capture clear images of the Meibomian glands, free of any artefacts, which were used for precise calculations of Meibomian gland contrast. RESULTS: The expression procedure had a significant impact on Meibomian gland contrast and length ratio immediately afterwards. The least square mean difference (95% CI) from baseline for Michelson contrast was -0.006 (-0.010, -0.001) and -1.048 (-2.063, -0.033) for simple contrast. The least square mean ratio of the gland length ratio immediately after the expression to baseline was 0.758 (0.618, 0.931). CONCLUSIONS: Following therapeutic expression, Meibomian glands exhibit reduced brightness and length. However, within 24 h, they appear to recover and return to their baseline state, indicating a relatively short recovery time. This sheds light on whether meibography is solely focused on capturing gland structure or if it also captures acinar activity. The hyperreflective properties of lipids suggest that the decrease in contrast observed after expression could be attributed to a reduction in the visualisation of acini activity. A decrease in Meibomian gland length ratio implies that the loss of gland structure following treatment may be indicative of a temporary structural alteration.
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PURPOSE: The aim of this pilot study was to investigate the initial effect of contact lens wear on spontaneous blink characteristics. METHODS: This was a randomised, crossover pilot study. Spontaneous blinking was recorded using a high-speed infrared camera in ten subjects with three different soft contact lenses (spherical hydrogel, spherical silicone hydrogel and toric hydrogel), one rigid contact lens and without contact lenses. Custom semi-automated software was used to determine palpebral aperture height, interblink interval (IBI), blink speed, blink completeness and blink duration. RESULTS: The IBI was significantly greater for non-lens wear compared with the silicone hydrogel [ratio (95% CI): 1.34 (1.16, 1.55), p < 0.0001], toric hydrogel [1.28 (1.10, 1.48), p = 0.0001] and rigid corneal lenses [1.48 (1.27, 1.73), p < 0.0001]. The spherical silicone hydrogel lens showed greater closing-phase speed than non-lens wear [mean difference (95% CI): 27.4 (5.6, 49.1) mm/s, p = 0.006]. Shorter total blink duration was found for non-lens wear compared with any of the lens types [spherical hydrogel: ratio 0.89 (0.81, 0.98), p = 0.01; spherical silicone hydrogel: 0.87 (0.80, 0.95), p = 0.0001; toric hydrogel: 0.90 (0.83, 0.98), p = 0.004; and rigid corneal: 0.88 (0.82, 0.96), p = 0.0004]. Opening-phase speed (p = 0.12) and blink completeness metrics (all p > 0.5) were not influenced by wearing condition. CONCLUSION: This work showed that short-term contact lens wear influenced the palpebral aperture height, IBI, speed and duration of the blink, and the effect is dependent on the contact lens type. The completeness of the blink was not altered by contact lens wear. Future work should be conducted to assess the effect of long-term wear of different contact lens types on blink characteristics. The measurement of spontaneous blinking characteristics represents an immediate, sensitive and non-invasive evaluation of the impact of a contact lens on the ocular surface.
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Piscadela , Lentes de Contato Hidrofílicas , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato , Hidrogéis , Projetos Piloto , SiliconesRESUMO
Meibography is a visualisation technique that has been used for over 40 years. There have been significant improvements in image quality, examination technique and image interpretation over this period. Although meibography has received sporadic reviews in the past, an updated review is timely due to the rapid recent rise of relevant technology and advances in both image processing and artificial intelligence. The primary aim of this paper is to review recent research into Meibomian gland imaging and update the community about the most relevant technologies and approaches used in the field.
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Síndromes do Olho Seco , Doenças Palpebrais , Inteligência Artificial , Síndromes do Olho Seco/diagnóstico , Doenças Palpebrais/diagnóstico , Humanos , Processamento de Imagem Assistida por Computador , Glândulas Tarsais/diagnóstico por imagem , LágrimasRESUMO
PURPOSE: To test the hypothesis that various subjective ocular and task-related parameters associated with wearing a face mask would be better in neophyte contact lens (CL) wear compared to habitual spectacle (Sp) wear. METHODS: Thirty participants were randomised to continue in Sp (n = 15) or wear somofilcon A daily disposable CL (n = 15) ('group'). A surgical face mask (Type II R) was worn for at least one hour per day on four or more days per week. After two weeks, participants completed the Quality of Life Impact of Refractive Correction Questionnaire (QIRC), a two-part face mask usability questionnaire and graded ocular-related symptoms using 0-100 visual analogue scales. RESULTS: There was no difference between groups for overall QIRC score but some individual question scores reflected better quality of life in the CL: 'outdoor activities', 'keep fit' and 'able to do things' (all p < 0.05). Differences in favour of the CL were seen for the following in the face mask usability questionnaire: 'breathing', 'heat', 'comfort on ears', 'overall comfort', 'walking', 'driving', 'reading', 'computer use', 'exercising' and 'socialising' (all p < 0.05). Significant differences were also seen for the 0-100 VAS symptoms probing vision quality in favour of the CL: glare, distance and near vision, fogging, restricted field of view and peripheral blur. CONCLUSION: This work supports anecdotal reports that CL are a better vision correction option than Sp when used in conjunction with a face mask. Participants reported a range of benefits to the CL/face mask combination for vision-related symptoms, breathing and heat-related symptoms and a number of day-to-day activities including walking, driving and exercising. All of the benefits relating to the CL are likely to result in improved adherence to face mask use. Overall, the findings of this work suggest that where possible, CL should be the preferred vision correction option for people using face masks.
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Lentes de Contato Hidrofílicas , Lentes de Contato , Óculos , Humanos , Máscaras , Satisfação do Paciente , Qualidade de Vida , Acuidade VisualRESUMO
PURPOSE: This work set out to investigate if there was an association between subjective comfort and both subjective and measured vision during the use of contemporary daily disposable soft toric contact lenses. METHODS: Thirty-eight habitual soft contact lens wearers wore each of three daily disposable toric lenses for one week in a prospective, crossover, randomised, single-masked study. The following clinical measures were recorded at dispensing and follow-up visits: biomicroscopy scores, lens fitting (including rotation and rotational stability), high and low contrast visual acuity, subjective vision quality and subjective ocular surface comfort. Subjective scores were collected using 0-10 numerical grading scales. Comfort scores were analysed using a linear regression model with age, sex, visit, phase of crossover ('phase'), lens type, lens rotation, lens rotational stability, visual acuity, cylinder power and subjective vision quality as factors of interest and then refined using backward stepwise regression. RESULTS: Thirty six participants (31.1 ± 13.5 years) completed the study. Comfort scores were found to be associated with subjective vision quality (F = 127.0 ; p < 0.0001), phase (F = 7.2; p = 0.001) and lens type (F = 4.9; p = 0.009). Greater comfort scores were observed with greater subjective vision quality scores. Visual acuity was not statistically significant in the model. CONCLUSION: This work suggests that symptoms of ocular discomfort may be more intense if there is also perceived visual compromise in daily disposable soft toric lenses. There was a stronger positive correlation between comfort and subjective vision quality compared with comfort and measured visual acuity.
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Lentes de Contato Hidrofílicas , Satisfação do Paciente , Humanos , Estudos Prospectivos , Visão Ocular , Acuidade VisualRESUMO
Contact lenses in the future will likely have functions other than correction of refractive error. Lenses designed to control the development of myopia are already commercially available. Contact lenses as drug delivery devices and powered through advancements in nanotechnology will open up further opportunities for unique uses of contact lenses. This review examines the use, or potential use, of contact lenses aside from their role to correct refractive error. Contact lenses can be used to detect systemic and ocular surface diseases, treat and manage various ocular conditions and as devices that can correct presbyopia, control the development of myopia or be used for augmented vision. There is also discussion of new developments in contact lens packaging and storage cases. The use of contact lenses as devices to detect systemic disease has mostly focussed on detecting changes to glucose levels in tears for monitoring diabetic control. Glucose can be detected using changes in colour, fluorescence or generation of electric signals by embedded sensors such as boronic acid, concanavalin A or glucose oxidase. Contact lenses that have gained regulatory approval can measure changes in intraocular pressure to monitor glaucoma by measuring small changes in corneal shape. Challenges include integrating sensors into contact lenses and detecting the signals generated. Various techniques are used to optimise uptake and release of the drugs to the ocular surface to treat diseases such as dry eye, glaucoma, infection and allergy. Contact lenses that either mechanically or electronically change their shape are being investigated for the management of presbyopia. Contact lenses that slow the development of myopia are based upon incorporating concentric rings of plus power, peripheral optical zone(s) with add power or non-monotonic variations in power. Various forms of these lenses have shown a reduction in myopia in clinical trials and are available in various markets.
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Lentes de Contato , Miopia , Presbiopia , Erros de Refração , Olho , Humanos , Refração Ocular , Erros de Refração/diagnóstico , Erros de Refração/terapiaRESUMO
PURPOSE: To investigate ocular discomfort during contact lens wear using a wrist-mounted electronic 'lens awareness logger' (LAL). METHODS: Thirty symptomatic contact lens wearers wore study contact lenses for three days. On the first two days, two lens types which are known to differ in end-of-day comfort (lens A: senofilcon A and lens B: balafilcon A), were worn as a matching pair (randomised order). On day three, a pair of lens B was worn. On each day, the participant used a LAL. On day one and two, the participant pressed a button on the LAL whenever they became aware of their lenses due to discomfort. On day three, the participant used a multiple click protocol (1â¯=â¯mild awareness to 3â¯=â¯severe awareness) to report discomfort. RESULTS: LAL events were similar on days one and two (17.3 vs. 15.8 events per day). There were significantly more LAL events for lens B (21.6 events per day) in comparison with lens A (11.6 events per day) (pâ¯=â¯0.006). The LAL event profile highlighted peaks in awareness following lens application and towards the end of the wearing cycle. Comparison of the LAL event profile for the two lens types showed significant differences in lens awareness, particularly in the first half of the wearing cycle. LAL events on day 3, showed a uniform distribution of single and double clicks through the day, but a marked peak in triple clicks in the last two hours of lens wear. CONCLUSION: The LAL was able to differentiate between the study lenses and demonstrated differences in their LAL event profiles. Lens awareness associated with discomfort appeared to increase not only in frequency, but also in intensity towards the end of the wearing cycle. The ability of the LAL to track lens awareness suggests it is likely to be a useful tool in furthering understanding of ocular discomfort.
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Lentes de Contato Hidrofílicas , Lentes de Contato , Lentes de Contato Hidrofílicas/efeitos adversos , Eletrônica , Olho , Humanos , Satisfação do Paciente , Visão Ocular , PunhoRESUMO
PURPOSE: Fluorescein-labelled wheat germ agglutinin (F-WGA) acts as a marker for ocular surface mucins. This clinical study sought to investigate whether the degree of F-WGA fluorescence observed at the ocular surface differed between symptomatic contact lens wearers, asymptomatic contact lens wearers and non-contact lens wearers, using a novel imaging system. METHODS: Twenty-five participants (10 symptomatic contact lens wearers, 10 asymptomatic contact lens wearers and 5 non-contact lens wearers) attended a single study visit. Photographs of the cornea, bulbar and tarsal conjunctiva were captured following application of F-WGA solution. RESULTS: The imaging system captured high-resolution images of F-WGA fluorescence at the ocular surface. The degree of fluorescence differed between the ocular surface regions (pâ¯<â¯0.001). A significant difference in fluorescence was observed between participant groups for the cornea (pâ¯=â¯0.01), with both the symptomatic and asymptomatic contact lens wearers showing lower fluorescence than the non-lens wearers. F-WGA associated fluorescence appeared diminished in the lid wiper region of the symptomatic lens wearers, compared to the asymptomatic group (pâ¯=â¯0.025). CONCLUSION: The use of F-WGA as a clinical marker for ocular surface mucins allows an improved understanding of their distribution across the ocular surface. Contact lens wear appears to negatively impact mucin density across the ocular surface, with the most marked effect on the cornea. F-WGA fluorescence appeared diminished in the lid wiper region for the symptomatic contact lens wearing group, indicating that mechanical interaction in this region may play a role in the aetiology of contact lens discomfort. Given the ability of F-WGA to disclose mucin distribution across the ocular surface it is likely to be a key clinical tool in furthering our understanding of (i) the aetiology of contact lens related discomfort, (ii) contact lens designs/materials to minimise interaction with the ocular surface and (iii) dry eye disease and other ocular surface diseases.
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Lentes de Contato Hidrofílicas , Síndromes do Olho Seco , Túnica Conjuntiva , Humanos , Mucinas , Imagem ÓpticaRESUMO
PURPOSE: To develop and evaluate a wearable device (the lens awareness logger, LAL) to record subjective lens awareness during contact lens wear. METHODS: The LAL is a compact electronic event-logging device incorporating a tactile switch and belt-clip. Forty contact lens wearers (20 symptomatic and 20 asymptomatic) took part in a clinical evaluation of the LAL device. Subjects were instructed to wear their habitual soft contact lenses for 2 days (>8 h wear) and use the LAL device. Subjects activated the LAL device immediately prior to lens application and deactivated it following lens removal. If a subject became aware of their contact lenses at any point throughout the wear period they were instructed to depress the button on the LAL device. RESULTS: The mean number of lens awareness events per hour was 1.3, although there was substantial variation between subjects (standard deviation 1.4). The distribution of lens awareness events throughout the contact lens wearing period showed significantly elevated awareness following lens application and prior to lens removal (p < 0.0001). In addition, symptomatic subjects had a statistically higher percentage of LAL events in the second half of the lens-wearing day compared with asymptomatic subjects (p = 0.02). The LAL findings for each subject appear consistent across the two days (i.e. no fatigue or learning effect). The LAL device was well accepted by subjects with 38 of the 40 subjects reporting it was either 'very easy' or 'fairly easy' to use. CONCLUSION: The LAL device was able to monitor ocular comfort throughout a period of contact lens wear and was well accepted by subjects. The ability of the LAL device to track ocular awareness events through the day, with high temporal resolution, means it is likely to be a key tool to further understanding of contact lens associated discomfort and dry eye disease.
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Lentes de Contato Hidrofílicas , Monitorização Fisiológica/métodos , Conforto do Paciente/estatística & dados numéricos , Satisfação do Paciente , Dispositivos Eletrônicos Vestíveis , Adolescente , Adulto , Síndromes do Olho Seco/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Inquéritos e QuestionáriosRESUMO
This work sought to undertake a comprehensive investigation of the measurement errors associated with contact angle assessment of curved hydrogel contact lens surfaces. The contact angle coefficient of repeatability (COR) associated with three measurement conditions (image analysis COR, intralens COR, and interlens COR) was determined by measuring the contact angles (using both sessile drop and captive bubble methods) for three silicone hydrogel lenses (senofilcon A, balafilcon A, lotrafilcon A) and one conventional hydrogel lens (etafilcon A). Image analysis COR values were about 2 degrees , whereas intralens COR values (95% confidence intervals) ranged from 4.0 degrees (3.3 degrees , 4.7 degrees ) (lotrafilcon A, captive bubble) to 10.2 degrees (8.4 degrees , 12.1 degrees ) (senofilcon A, sessile drop). Interlens COR values ranged from 4.5 degrees (3.7 degrees , 5.2 degrees ) (lotrafilcon A, captive bubble) to 16.5 degrees (13.6 degrees , 19.4 degrees ) (senofilcon A, sessile drop). Measurement error associated with image analysis was shown to be small as an absolute measure, although proportionally more significant for lenses with low contact angle. Sessile drop contact angles were typically less repeatable than captive bubble contact angles. For sessile drop measures, repeatability was poorer with the silicone hydrogel lenses when compared with the conventional hydrogel lens; this phenomenon was not observed for the captive bubble method, suggesting that methodological factors related to the sessile drop technique (such as surface dehydration and blotting) may play a role in the increased variability of contact angle measurements observed with silicone hydrogel contact lenses.