Purpose: Vital staining is one of the most widely test used to evaluate the corneal damage. The aim of this study was to assess the relationship of the corneal damage with tear meniscus height (TMH) and dry eye symptomatology. Material and methods: 530 subjects were recruited among patients of the Optometry Clinic (USC). Previously, all of them completed an OSDI questionnaire. Two videos of the ocular surface were recorded from each patient by a digital camera attached to a slit-lamp. Firstly, a video of central tear meniscus under 40x with the Tearscope device illumination was recorded. From those videos, a masked observer extracted one image and TMH was measured by using the ImageJ software. Secondly, after fluorescein instillation, the corneal surface was recorded by another experienced masked observer, who assigned a category to the corneal damaged based on the Oxford Scheme. The evaluation was stratified by corneal zones based on the CCLRU grading scales (central, superior, inferior, nasal and temporal). Results: When the sample was grouped by the corneal staining Oxford Grade, there was found a statistical difference between groups in OSDI and TMH value (ANOVA: both p≤0.006). There was found a difference in OSDI value when corneal damage was in nasal or inferior areas (t-test; both p≤0.015), and a difference in TMH value arises when damage was in the central, nasal or inferior areas (t-test; all p≤0.013). Conclusions: There is a relationship between corneal damage grade and corneal zones with dry eye symptomatology and tear film volume.
Purpose: Tranaglyphs and Vectograms are visual therapy material based on red/green or polarized targets respectively that used similar but slightly different images for each eye to train fusion and vergence skills. This study aimed to analyse the relationship of three accommodative parameters (the Negative Relative Accommodation [NRA], the Positive Relative Accommodation [PRA] and the Accommodative Amplitude [AA]) with the results of four different visual therapy vectograms/tranaglyphs. Material and methods: 45 subjects free of any accommodative or binocular problem were recruited among students attending the Optometry Clinic of the Optometry Faculty (USC). In a first session, the accommodative tests were performed according to their standard protocols. In a second session, following manufacturer’s instructions, the subjects performed in a random order four different calibrated vectograms/tranaglyphs: two red/green Variable Demand Anaglyphs (one based on circles [VDA-C] and one on draws [VDA-D]), one red/green Fixed Demand Anaglyph [FDA], and one polarized with Variable Demand [VDP]. Subjects were asked to indicate the maximum value both base-out (BO) and base-in (BI), where the image fusion was lost. Results: NRA showed a negative correlation with the BO results of the VDP (p = 0.040, r = -0.270). PRA showed a negative correlation with the BO results of the VDA-C, the VDA-D and the VDP (all p ≤0.017, r ≥ -0.323). AA showed a positive correlation with the BI results of the VDA-D, the FDA, and the VDP (all p ≤0.013, r ≥0.341). Conclusion: Accommodation seems to have some influence on the visual therapy training with vectograms and tranaglyphs.
Purpose: Meibography images bring information about the status and integrity of the meibomian glands (MG). The aim of this study was to correlate the meibomian gland loss area (MGLA) with age and dry eye symptomatology. Material and methods: A total of 110 subjects were recruited for the study. From the Meibography images obtained with the Topcon® CA-800 topographer, MGLA was calculated as the difference between the total area of the tarsus and the MG presence area measured by using the ImageJ software. Before examination, all subjects completed an OSDI questionnaire. OSDI scores were grouped in 4 severity categories: normal (score ≤12), mild (score 12–22), moderate (score 22–32) and severe (score ≥32). Age were categorised in 3 subgroups: ≤25 years, from 25 to 45 years and ≥45 years. MGLA was also grouped in 4 categories of loss: ≤25 %, from 25 to 50%, from 50 to 75% and ≥75%. Results: Analysis was performed by dividing the sample in the 4 MGLA subgroups; these subgroups showed differences in age (p=0.029; Kruskal-Wallis test) and differences in OSDI scores (p=0.001; Kruskal-Wallis test). Sample was divided in 3 age subgroups and differences were obtained in MGLA values among subgroups (p<0.001; Kruskal-Wallis test). Samples was divided in 4 OSDI subgroups and differences were obtained in MGLA values among subgroups (p=0.003; Kruskal-Wallis test). Positive correlation (Spearman Correlation) were obtained for both, MGLA vs. age (r=0.329, p<0.001) and MGLA vs. OSDI (r=0.380, p<0.001). Conclusion: In the present study MGLA showed a relationship with age and OSDI.
Purpose: Tear film meniscus evaluation offers a non-invasive indication of the total volume of the tear. The aim of this study was to analyse the relationship between the central tear meniscus area with symptomatology and tear film stability. Material and methods: 120 participants who completed an OSDI questionnaire were enrolled in the study. After fluorescein instillation, two videos were recorded by a digital camera attached to a slit-lamp. The first video recorded the lower central portion of the tear meniscus (6 o’clock) with a short light beam (3x5mm), and the second one recorded the complete ocular surface obtaining the Break-Up time (BUT) and Maximum Blink Interval (MBI). A self-design program (FWCapture) was used to acquire the videos while the participants were requested to keep the eye open for as long as possible three times. Images were extracted from each video by a masked observer. From de first video, Central Tear Meniscus Area with fluorescein (CTMAF) was “manually” measured by using ImageJ software (command “<<freehand tool”). From the second video, BUT and MBI were determined by counting video frames then converted in seconds; both parameters were averaging using only the two most similar measurements. Results: CTMAF showed a negative correlation with OSDI score (Spearman Rho: p <0.001, r=-0.372). There was found a statistical difference in the CTMAF between OSDI subgroups (Kruskal-Wallis: p=0.001). CTMAF showed a positive correlation with BUT/MBI (Spearman Rho: both p ≤0.003, r≥0.246). Conclusions: Tear film volume showed a relationship with the symptomatology and tear film stability.
Purpose: Accommodative anomalies are a group of different visual problems that reduce the efficiency of the visual system. Binocular accommodative facility (BAF) therapy is used to train the ability of the eye to repeatedly change its accommodative state when changing focus between two focal planes during periods of time. The aim of this study was to evaluate the effect of BAF training with standard flipper dioptric treatments on a group of non-symptomatic young adults. Material and methods: 67 subjects were recruited among students attending the Optometry Clinic of the Optometry Faculty (USC, Spain). All of them had good general health and were free of any accommodative or binocular problems. Subjects were scheduled to four session one-week apart. In each session, they were requested to measure the BAF in cycles/minute (cpm) with a ±2.00D flipper while focusing a near test at 40 cm. Patients were also requested to point the difficulty for clearing with the minus, plus or with none pair of lenses. Results: There was found a statistical difference on BAF between the first and the final session when the whole sample was analysed (paired t-test: p <0.001), and when the sample was grouped by lens clearing difficulties (paired t-test: all p ≤0.005). BAF showed a statistically significant difference between results obtained in each session (ANOVA: p =0.002), and between the results of contiguous paired sessions (paired t-test: all p ≤0.047). Conclusion: The present study showed the positive effect of traditional dioptric training in amplitude flexibility improvement.
Purpose: To validate the performance of a new objective application designated iDEAS (Dry Eye Assessment System) to categorize different zones of lipid layer patterns (LLPs) in one image. Material and methods: Using the Tearscopeplus and a digital camera attached to a slit-lamp, 50 images were captured and analyzed by 4 experienced optometrists. In each image the observers outlined tear film zones that they clearly identified as a specific LLP. Further, the categorization made by the 4 optometrists (called observer 1, 2, 3 and 4) was compared with the automatic system included in iDEAS (5th observer). Results: In general, observer 3 classified worse than all observers (observers 1, 2, 4 and automatic application, Wilcoxon test, <0.05). The automatic system behaved similar to the remaining three observers (observer 1, 2 and 4) showing differences only for Open meshwork LLP when comparing with observer 4 (Wilcoxon test, p=0.02). For the remaining two observers (observer 1 and 2) there was not found statistical differences (Wilcoxon test, >0.05). Furthermore, we obtained a set of photographs per LLP category for which all optometrists showed agreement by using the new tool. After examining them, we detected the more characteristic features for each LLP to enhance the description of the patterns implemented by Guillon. Conclusions: The automatic application included in the iDEAS framework is able to provide zones similar to the annotations made by experienced optometrists. Thus, the manual process done by experts can be automated with the benefits of being unaffected by subjective factors.
Purpose: Different lower tear meniscus parameters can be clinical assessed on dry eye diagnosis. The aim of this study was to propose and analyse the variability of a semi-automatic method for measuring lower tear meniscus central area (TMCA) by using open source software. Material and methods: On a group of 105 subjects, one video of the lower tear meniscus after fluorescein instillation was generated by a digital camera attached to a slit-lamp. A short light beam (3x5 mm) with moderate illumination in the central portion of the meniscus (6 o’clock) was used. Images were extracted from each video by a masked observer. By using an open source software based on Java (NIH ImageJ), a further observer measured in a masked and randomized order the TMCA in the short light beam illuminated area by two methods: (1) manual method, where TMCA images was “manually” measured; (2) semi-automatic method, where TMCA images were transformed in an 8-bit-binary image, then holes inside this shape were filled and on the isolated shape, the area size was obtained. Finally, both measurements, manual and semi-automatic, were compared. Results: Paired t-test showed no statistical difference between both techniques results (p = 0.102). Pearson correlation between techniques show a significant positive near to perfect correlation (r = 0.99; p < 0.001). Conclusions: This study showed a useful tool to objectively measure the frontal central area of the meniscus in photography by free open source software.
In optometry, hyperemia is the accumulation of blood flow in the conjunctival tissue. Dry eye syndrome or allergic conjunctivitis are two of its main causes. Its main symptom is the presence of a red hue in the eye that optometrists evaluate according to a scale in a subjective manner. In this paper, we propose an automatic approach to the problem of hyperemia grading in the bulbar conjunctiva. We compute several image features on images of the patients' eyes, analyse the relations among them by using feature selection techniques and transform the feature vector of each image to the value in the adequate range by means of machine learning techniques. We analyse different areas of the conjunctiva to evaluate their importance for the diagnosis. Our results show that it is possible to mimic the experts' behaviour through the proposed approach.
To measure different parameters of lower tear meniscus height (TMH) by using photography with open software of measurement. TMH was addressed from lower eyelid to the top of the meniscus (absolute TMH) and to the brightest meniscus reflex (reflex TMH). 121 young healthy subjects were included in the study. The lower tear meniscus was videotaped by a digital camera attached to a slit lamp. Three videos were recorded in central meniscus portion on three different methods: slit lamp without fluorescein instillation, slit lamp with fluorescein instillation and TearscopeTM without fluorescein instillation. Then, a masked observed obtained an image from each video and measured TMH by using open source software of measurement based on Java (NIH ImageJ). Absolute central (TMH-CA), absolute with fluorescein (TMH-F) and absolute using the Tearscope (TMH-Tc) were compared each other as well as reflex central (TMH-CR) and reflex Tearscope (TMH-TcR). Mean ± S.D. values of TMH-CA, TMH-CR, TMH-F, TMH-Tc and TMH-TcR of 0.209 ± 0.049, 0.139 ± 0.031, 0.222 ± 0.058, 0.175 ± 0.045 and 0.109 ± 0.029 mm, respectively were found. Paired t-test was performed for the relationship between TMH-CA – TMH-CR, TMH-CA – TMH-F, TMH-CA – TMH-Tc, TMH-F – TMH-Tc, TMH-Tc – TMH-TcR and TMH-CR – TMH-TcR. In all cases, it was found a significant difference between both variables (all p < 0.008). This study showed a useful tool to objectively measure TMH by photography. Eye care professionals should maintain the same TMH parameter in the follow-up visits, due to the difference between them.
The lipid layer plays a major role in limiting evaporation of the tear film. Based on interference phenomena, there is a test directed to lipid layer pattern (LLP) evaluation, but is affected by subjective interpretation of the patterns. The aim of this study is to compare the LLP evaluation between two experienced observers on a group of healthy patients. Furthermore, the observers re-evaluated the same images in order to check their individual repeatability. LLP was examined using a Tearscope-plus (Keeler, Windsor, UK) attached to a slit lamp. Tear film was recorded by a Topcon DV-3 digital camera video and LLP images were captured. This yielded 124 LLP images that were categorized (based on Guillon’s schema) by two expert observers in two sessions separated by one month. Interobserver repeatability and intraobserver repeatability between both sessions were studied by using Cohen’s kappa coefficient. Comparing LLP categorization between both observers, Cohen's kappa coefficient was 0.615 and 0.633 for first and second session, respectively. When comparing LLP categorization by the same observer between both sessions, Cohen's kappa coefficient was 0.770 and 0.812 for Observer 1 and Observer 2. These results indicate substantial correlation in all cases [range of 0.61–0.80]. The most frequent misinterpretations were between open and closed meshwork and Wave and closed meshwork patterns. Although substantial correlation was found between categorizations of experienced observers, misinterpretation of the patters may appear even in the same observer. Some misinterpretations between adjacent patterns could be palliated by including intermediate patterns between those categories.
Tear film breakup time (BUT) test only examines the first break in the tear film, but subsequent tear film events are not monitored. We present a method of measuring the area of breakup after the appearance of the first breakup by using open source software. Furthermore, the speed of the rupture was determined. 84 subjects participated in the study. 2 μl volume of 2% sodium fluorescein was instilled using a micropipette. The subject was seated behind a slit-lamp using a cobalt blue filter together with a Wratten 12 yellow filter. Then, the tear film was recorded by a camera attached to the slit lamp. 4 frames of each video was extracted, the first rupture (BUT_0), breakup after 1 second (BUT_1), rupture after 2 seconds (BUT_2) and breakup before the last blink (BUT_F). Open source software of measurement based on Java (NIH ImageJ) was used to measure the number of pixels in areas of breakup. These areas were divided by the area of exposed cornea to obtain the percentage of ruptures. Instantaneous breakup speed was calculated for second 1 as the difference between BUT_1 - BUT_0, whereas instant speed for second 2 was BUT_2 - BUT_1. Mean area of breakup obtained was: BUT_0 = 0.26%, BUT_1 = 0.48%, BUT_2 = 0.79% and BUT_F = 1.61%. Break speed was 0.22 area/sec for second 1 and 0.31 area/sec for second 2, showing a statistical difference between them (p = 0.007). Post BUT analysis may be easily monitoring with the aid of this software.
The purpose of this study is to establish the procedure of acquisition and evaluate the Lipid layer pattern (LLP) by Tearscope in order to enhance this useful technique. To aid this purpose, we present a new broad LLP images database (included in a web application called Pli-marker) The tear film lipid layer was examined using a Tearscope-plus (Keeler, Windsor, UK). To capture LLPs videos a Topcon DV-3 digital camera was used and attached to the slit lamp. All videos were stored in a computer via Topcon IMAGEnet i-base software and LLP images were obtained and uploaded at Pli-marker web application, which offers the manual selection of regions associated to a specific LLP. 50 images were analysed by 4 experienced optometrists. Each of them marked (using Pli-marker) those areas in the 50 images that corresponded with some of the 5 LLP: open meshwork (OM), closed meshwork, (CM), wave (W), amorphous (AM) and color fringe (CO). From the 50 images we obtained 25 areas of OM, 22 areas of CM, 20 areas of W, 46 areas of AM and 17 areas of CO that 4 observers were in accordance. We present an example of 4 pictures for each area of concordance together with the description of the features used for categorizing the LLP in our study. This work describes the methodology used in our research project, including settings for capture image, and the criteria for subjective categorization of the LLP accomplished by a set of images.
High tear fluid osmolarity is a feature common to all types of dry eye. This study was designed to establish the accuracy of two osmometers, a freezing point depression osmometer (Fiske 110) and an electrical impedance osmometer (TearLab™) by using standard samples. To assess the accuracy of the measurements provided by the two instruments we used 5 solutions of known osmolarity/osmolality; 50, 290 and 850 mOsm/kg and 292 and 338 mOsm/L. Fiske 110 is designed to be used in samples of 20 μl, so measurements were made on 1:9, 1:4, 1:1 and 1:0 dilutions of the standards. Tear Lab is addressed to be used in tear film and only a sample of 0.05 μl is required, so no dilutions were employed. Due to the smaller measurement range of the TearLab, the 50 and 850 mOsm/kg standards were not included. 20 measurements per standard sample were used and differences with the reference value was analysed by one sample t-test. Fiske 110 showed that osmolarity measurements differed statistically from standard values except those recorded for 290 mOsm/kg standard diluted 1:1 (p = 0.309), the 292 mOsm/L H2O sample (1:1) and 338 mOsm/L H2O standard (1:4). The more diluted the sample, the higher the error rate. For the TearLab measurements, one-sample t-test indicated that all determinations differed from the theoretical values (p = 0.001), though differences were always small. For undiluted solutions, Fiske 110 shows similar performance than TearLab. However, for the diluted standards, Fiske 110 worsens.
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