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The aim of this study is to ascertain whether the quantity and quality of tear and eye subjective comfort are influenced by the temperature, humidity and oral Contraceptives Taking or Non-taking (CTNT). Forty-one students, females, from the University of Minho, Braga, Portugal, aged (mean±1standard deviation) of 21.51±1.85 years, ranging from 20 to 30 years, participated in this study. The McMonnies Questionnaire (MMQ), Break Up Time (BUT) and Phenol Red Test (PRT) were accessed between 14-17 hours in four sets of visits throughout the year: Visit 1, Visit 2, Visit 3 and Visit 4. The PRT and BUT values (mean±1standard deviation) for Visit 1, Visit 2, Visit 3 and Visit 4 were respectively 23.88±6.50mm, 22.29±8.00mm, 23.61±6.75mm, 22.88±7.00mm and 6.02±1.58s, 5.62±1.22s, 5.23±0.88s, 5.53±1. 42s. The MMQ scores for Visit 1, Visit 2, Visit 3 and Visit 4 ranged from 2-13, 2-15, 1-14 and 2-14 with medians of 6, 7, 6 and 6, respectively. The influence of temperature, humidity and CTNT on PRT, BUT and MMQ were evaluated using generalized linear mixed model. For BUT and MMQ statistical significant effects were found regarding temperature and humidity. The temperature and humidity influenced the tear quality and subjective comfort but did not influence the tear quantity. The CTNT did not influence tear quantity, quality or subjective eye comfort.

Purpose. The photostress recovery time test (PSRT) has been widely reported as a helpful screening clinical tool. However, the poor standardization of its measurement technique remains to be a limitation among clinicians. The purpose of this study is to apply a recommended clinical technique to measure the PSRT in some of the most commons eye diseases to ascertain whether these diseases affect the PSRT values. Methods. One hundred and one controls and 105 patients, with diagnosed diabetes (without visible signs of diabetic retinopathy), primary open angle glaucoma (POAG) or cataracts underwent photostress testing. The test was performed with a direct ophthalmoscope for illuminating the macula for 30 seconds. Participants belonged to three age classes: A, B and C; and were divided into four groups: control, diabetic, POAG and cataract. The age range for A, B and C classes were respectively 43-54, 55-64 and 65-74 years. The groups were also further compared within each age class. In addition, the influence of age on PSRT was evaluated using the control group. Results. Results demonstrate that PSRT changes with age (p

A new experimental setup for any standard Video Display Unit (VDUET) with dichromatic glasses was developed for fixation disparity (FD) accessing. A computer software produce a dark field with white targets for central and peripheral fusion and two lines colors red and green for dissociated vision with the use of red and green filters. These lines can be moved right or left by the subject, until are seen apparently aligned. The real displacement between the lines is then recorded. The fixation curve (FC) is obtained by the interposition of prisms before one or both eyes, as in a regular commercial FD test. A comparison for FD and measurement time between this experimental setup and two commercially available methods, Wesson and Saladin cards, was performed in thirty-two university students. The means slope, x-intercept and y-intercept were 0.13, -0.22 and -5.63 for Saladin; 0.01, -2.29 and -1.88 for Wesson; and 0.61, -1.33 and -2.46 for VDUET. The mean measurement test time was 582.3 s, 501.3 s and 444.8 s for Saladin, Wesson and VDUET. The FC measured by these three methods was different but not statically significant (ANOVA one-way, Tukey post-hoc test) with the exception of the slope between Wesson test and VDUET (p

The aim of this method is to determine the thickness of a transparent medium, close to the corneal thickness, using the angle at the first and second Purkinje images are aligned for a specific optical slit width. An optical slit is projected in an oblique angle relatively to the transparent medium, producing two different reflections in each medium surface (first and second Purkinje images). The slit is then moved until the first and second Purkinje images of the slit are aligned in such a way, that look as if they were a continuous slit. The slit width, the angle between the illumination and observation, and the medium index are used, then, to calculate the medium thickness. This method was implemented in a slit lamp and the central thicknesses (CT) of nine gas-permeable contact lenses (CL) were measured, with this method and a mechanical gauge and the results were compared. The mean CT difference ± standard deviation, between the two methods was 0.004 ± 0.008 mm with minimum and maximum absolute values of 0.002 and 0.019 mm. This technique showed good precision to measure the CT of CL and should be tried in human corneas.