Genís Cardona

Blink rate, blink amplitude, and tear film integrity during dynamic visual display terminal tasks.

Purpose: The present study aimed at investigating the influence of the level of dynamism of two different visual display terminal tasks on spontaneous eyeblink rate, blink amplitude, and tear film integrity. Material and Methods: A total of 25 healthy, young volunteers participated in the study. Blink rate and blink amplitude were recorded in silent primary gaze conditions and while subjects were playing two computer games of similar cognitive demands but different rate of visual information presentation. For each experimental condition, tear volume was evaluated by measuring meniscus height and with the red phenol thread test. Fluorescein and non-invasive break-up time tests, as well as the observation of interference patterns and the estimation of the dry area extension, were employed to assess tear stability. Results: Statistically significant differences were revealed in blink rate (F = 595.85, p < 0.001) and blink amplitude (χ2 = 34.00, p < 0.001), with blink rate during fast- and slow-paced game play decreasing to almost 1/3 and 1/2 of baseline levels, respectively, and with a larger percentage of incomplete blinks during dynamic tasks. Fluorescein and non-invasive break-up time tests and dry area extension were able to differentiate between experimental conditions in general (F = 408.42, p < 0.001; F = 163.49, p < 0.001; χ2 = 20.74, p < 0.001), as well as between fast- and slow-paced games, thus suggesting that tear quality was more affected than tear volume. Conclusions: Blink rate, blink amplitude, and tear film stability were compromised during the most dynamic visual display terminal task, suggesting a negative influence of not only the cognitive aspects of the task, but also of the rate at which new visual information is presented. Frequent breaks and blinking awareness training are recommended for visual display terminal users requiring prolonged periods of visually demanding dynamic computer play or work.

Optical quality and intraocular scattering in a healthy young population

Background:  We objectively assessed the optical quality and intraocular scattering by means of parameters provided by a clinical double‐pass system in healthy young subjects and thereby we obtained new reference data for clinical diagnosis. We calculated normal values of neural contrast sensitivity function (nCSF) from the measured modulation transfer function (MTF) and the contrast sensitivity function (CSF).

Visual Acuity, Contrast Sensitivity, Subjective Quality of Vision, and Quality of Life with 4 Different Multifocal IOLs:

Purpose This prospective, randomized, double-masked, clinical trial was designed to evaluate visual acuity, contrast sensitivity, subjective quality of vision, and quality of life in 47 patients symmetrically, and randomly, implanted with 4 different IOL designs (SN6AD1, SN60D3, ReZoom NXG1, and Tecnis ZMA00), 3 months after cataract intervention. Methods Binocular corrected and uncorrected distance visual acuity, binocular distance corrected (BCNVA) and uncorrected (UCNVA) near visual acuity, binocular distance corrected (BCIVA) and uncorrected (UCIVA) intermediate visual acuity, photopic, mesopic, and mesopic with glare contrast sensitivity, quality of vision, and quality of life were evaluated. Results Statistically and clinically significant differences were found in BCNVA and UCNVA at 33 cm between high and low add power IOLs, while diffractive SN6AD1 lenses achieved better UCNVA at 40 cm than refractive ReZoom IOLs. Asphericity and low add power were found to improve BCIVA. Contrast sensitivity was similarly compromised in all IOL models, although diffractive optics and aspheric profiles performed better in mesopic conditions. All IOL types received similar overall satisfaction and quality of life scores. Whereas ReZoom patients depended on their spectacles for near tasks, intermediate vision was spectacle independent. Photic phenomena were present in all IOLs, albeit more frequent in ReZoom IOLs. Conclusions The present results, which reflect IOL characteristics in optics, profile, and add power, may contribute to help surgeons decide on the type of IOL most suitable for each patient, especially those with high visual demands at near and intermediate distances.

Optical quality after myopic photorefractive keratectomy and laser in situ keratomileusis: Comparison using a double-pass system

PURPOSE: To use a double‐pass system to compare the optical quality after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for mild to moderate myopia. SETTING: Universitat Politècnica de Catalunya, Terrassa, Barcelona Institute of Ocular Microsurgery, Barcelona, Spain. DESIGN: Comparative case series. METHODS: Optical quality was assessed with a clinical double‐pass system preoperatively and 3 months after PRK or LASIK. The modulation transfer function (MTF), retinal image quality parameters (MTF cutoff frequency, Strehl ratio), and intraocular scattering (objective scatter index [OSI]) were calculated. RESULTS: This study evaluated 34 eyes that had PRK and 55 eyes that had LASIK. Both PRK and LASIK had a statistically significant impact on retinal image quality, although no significant differences between the techniques were observed. The MTF at 30 cycles per degree decreased by a factor of 1.50 in the PRK group and by a factor of 1.32 in the LASIK group. The MTF cutoff frequency decreased by a factor of 1.04 in the PRK group and by a factor of 1.06 in the LASIK group. The Strehl ratio decreased by a factor of 1.10 and 1.07, respectively. Photorefractive keratectomy and LASIK increased the objective scatter index by factors of 1.48 and 1.57, respectively. Significant correlations between the preoperative refraction and the OSI were found. CONCLUSIONS: Retinal image quality was similarly reduced with PRK and LASIK, with no significant differences between the 2 methods. Some PRK patients had a residual refractive error that might have been related to corneal‐wound healing still present 3 months postoperatively. Financial Disclosure: Dr. Arjona is an investor in and Drs. Güell and Pujol are investors in and consultants to Visiometrics S.L., Terrassa, Spain. None of the other authors has a financial or proprietary interest in any material or method mentioned.

Comparison of far and near contrast sensitivity in patients symmetrically implanted with multifocal and monofocal IOLs.

Purpose A prospective, randomized, double-masked, clinical trial was designed to evaluate distance and near contrast sensitivity (CS) in patients symmetrically, and randomly, implanted with 4 different multifocal intraocular lens (MIOL) designs (ReSTOR SN6AD1, ReSTOR SN60D3, ReZoom NXG, and Tecnis ZMA00) and a monofocal control group (Tecnis ZA9003), 6 months after cataract intervention. Methods Photopic, mesopic, and mesopic with glare distance CS, as well as photopic near CS, was evaluated with the CSV-1000 CS test and the Vistech VCTS 6000 system, respectively, in a group of 180 patients attending the ophthalmology department of Sant Pau Hospital, Barcelona, for cataract intervention and lens implantation. Results Statistically and clinically significant differences were found between the monofocal and multifocal lens groups at all spatial frequencies and illumination conditions, both during distance and near CS evaluation (all p<0.05), with the monofocal lens offering the best performance in all cases. Contrast sensitivity was similarly compromised in all MIOL models at distance, although MIOLs with diffractive optics and aspheric profiles showed a non–statistically significant trend to perform better in mesopic conditions. Near CS was lower for refractive, distance dominant lens designs, particularly at medium to high spatial frequencies. Conclusions The present results, which reflect intraocular lens (IOL) characteristics in optics, profile, and add power, may contribute to help surgeons decide on the type of IOL most suitable for each patient by taking into consideration the individual needs for critical distance and near vision, both in terms of visual acuity and contrast sensitivity.

Temporal stability in the perception of dry eye ocular discomfort symptoms.

Purpose. A prospective longitudinal study was designed to investigate the ability of patients with tear deficiency to correctly recall their past symptoms. The ultimate goal of the study was to contribute to the ongoing research concerning the lack of association between dry eye symptomatology and clinical tests of tear film evaluation. Methods. A total of 26 subjects with ages ranging from 29 to 61 years participated in the study. All subjects reported symptoms associated with tear deficiency, although none had been diagnosed with dry eye disease. Subjects were instructed to grade their symptoms on two different occasions, at the precise moment they were experiencing them, by means of a home questionnaire, and through a recall questionnaire, which was administered within a maximum interval of 10 days from the first questionnaire. Tear evaluation tests were performed at this second time. Non-parametric statistical analyses were used to investigate the relationship between present and recalled symptoms and between symptoms and signs, as well as between the different dry eye tests. The contributions of age, gender, and recall period were also evaluated. Results. With the exception of irritation (p = 0.029) and scratchiness (p = 0.025), no statistically significant difference was encountered between home and recall questionnaires, although females were found to recall their symptoms slightly better than males (p = 0.048). An increase in the severity of the symptoms was associated with a better recollection (p = 0.007). Symptoms (home or recalled) and clinical signs were not correlated, although the recalled symptom of scratchiness presented moderately strong correlations with several dry eye tests. Conclusions. Although the lack of correlation between dry eye tests and symptoms mirrored previous research, symptoms recall was found to follow certain interesting patterns, similar to those published in pain research literature.

Blink Rate and Incomplete Blinks in Six Different Controlled Hard-Copy and Electronic Reading Conditions.

PURPOSE To evaluate spontaneous eye blink rate (SEBR) and percentage of incomplete blinks in different hard-copy and visual display terminal (VDT) reading conditions, compared with baseline conditions. METHODS A sample of 50 participants (29 females, age range, 18-74 years) were recruited for this study. All participants had good ocular health and reported no symptoms of dry eye (OSDI score < 15). Face video recordings were captured while participants observed in silence a landscape picture at 2 m (baseline) and during six different, 6-minute controlled reading experimental conditions. Texts were presented in electronic (tablet and computer display at 100% and 330% zoom levels) and hard-copy (text in book position in silence and aloud and text pasted on the computer display) formats. Video analysis was subsequently conducted to assess blink parameters. RESULTS All reading conditions resulted in a decrease in SEBR when compared with baseline conditions (all P < 0.001), with the least negative impact corresponding to reading in a 330% expanded display. The percentage of incomplete blinks was found to increase when reading was conducted on an electronic platform, in contrast to hard-copy text. CONCLUSIONS The high cognitive demands associated with a reading task led to a reduction in SEBR, irrespective of type of reading platform. However, only electronic reading resulted in an increase in the percentage of incomplete blinks, which may account for the symptoms experienced by VDT users. Spanish Abstract.

Comparison of Dynamic Visual Acuity Between Water Polo Players and Sedentary Students

In this study, we examined differences in dynamic visual acuity between elite and subelite water polo players and sedentary students. To measure dynamic visual acuity binocularly, we asked participants to indicate the orientation of a broken ring, similar to the Landolt C, which increased in size as it moved across a computer screen. Two different speeds, three possible trajectories, and two different levels of contrast were evaluated. There were statistically significant differences between elite players and sedentary students for each combination of speed, contrast, and trajectory. Elite players achieved better dynamic visual acuity scores, and results also improved for some combinations of speed, contrast, and trajectory. Comparison between elite and subelite groups failed to reveal any

Item by item analysis strategy of the relationship between symptoms and signs in early dry eye

Purpose: The present study aimed at analyzing the relationship between several particular symptoms, risk factors or global questionnaire scores and some tear clinical signs in early dry eye patients. Material and methods: A total of 77 volunteers were enrolled in the study without any prior classification, although patients with severe dry eye were excluded. Two questionnaires were used to assess ocular symptoms and risk factors, and clinical tear signs were evaluated with four tests (osmolarity, ferning, break-up time and the phenol red thread test). Multiple linear regression analysis was performed to determine the relative predictive value of each particular ocular symptom and risk factor, for each clinical sign. This analysis was repeated using symptoms and risk factors global scores. Results: The symptom “eyes stuck shut in the morning” was the only predictor variable for the sign “ferning crystallization” (R = 0.228, p < 0.05) and “dryness” for “break-up time” (R = –0.315, p < 0.01). “Burning sensation” and “computer use for more than 3 h” were predictor variables for “tear osmolarity” (R = 0.342, p < 0.01), while “itching” and “female gender” were found to predict the outcomes of the “phenol red thread test” (R = –0.462, p < 0.05). Global questionnaire scores were not found to predict any tear clinical sign. Conclusions: The present findings support the informative value of exploring the associations between clinical signs, ocular symptoms and risk factors by following an item by item strategy rather than opting for global questionnaire scores.

Knowledge and use of tear film evaluation tests by spanish practitioners

Purpose. The present study aimed at investigating the use and knowledge of tear film and dry eye evaluation tests by a representative sample of Spanish optometrists and ophthalmologists. Methods. A simple on-line survey was designed to explore the preferred tests for tear film evaluation and dry eye diagnosis. Additional questions surveyed knowledge of basic tear film evaluation concepts, attitude (proactive or reactive) toward patient symptoms and use of standardized dry eye questionnaires. Respondents also provided information regarding academic background, continuing education and training courses, and weekly number of tear film examinations. Results. A total of 140 optometrists and 103 ophthalmologists responded to the survey. The tear break-up time test was the first preference of optometrists and ophthalmologists, whereas the Schirmer test and the non-invasive break-up time were frequently reported by ophthalmologists and optometrists, respectively, to supplement a first test. Optometrists and ophthalmologists were similar in terms of continuing education, knowledge of basic tear film concepts, and attitude regarding symptoms. Continuing education was found to positively influence knowledge, attitude toward symptoms and use of more sophisticated tear film evaluation tests. Standardized dry eye questionnaires were rarely used. A strong positive statistically significant correlation was encountered between the number of continuing education and training courses and the number of weekly tear film examinations. Conclusions. Continuing education is an invaluable tool for practitioners to increase their self-confidence and improve their clinical practice when conducting tear film evaluations and dry eye diagnosis.