Eliciting blinks by transcutaneous electric nerve stimulation improves tear fluid in healthy video display terminal users: A self-controlled study.

We aimed to elicit strong blinks among healthy video display terminal (VDT) users by periorbital transcutaneous electric nerve stimulation (TENS) and evaluate its impact on the tear fluid and visual task. Appropriate TENS conditions were evaluated to evoke strong blinks under minimum discomfort. Seventeen healthy VDT users with noninvasive Keratograph first breakup time (NIKf-BUT) 5-15 s and Ocular Surface Disease Index (OSDI) scores < 15 were recruited in this study. Before the trial, noninvasive Keratograph average breakup time (NIKa-BUT), tear meniscus height (TMH) and OSDI scores were evaluated. Before each TENS session, the volunteers played Tetris while the corresponding blink rate and Tetris scores were recorded. Then, the participants underwent 30 minutes of TENS, which evoked blinking of their right eye 20 times per minute. Tetris scores were evaluated again during TENS. The Tetris scores and corresponding blink rate were assessed after each TENS session while NIKa-BUT, TMH and OSDI scores were recorded after the third and sixth TENS sessions. We found that OSDI scores declined significantly after the sixth TENS (P = .003). The NIKa-BUT of the right eye was promoted after the sixth TENS (P = .02), and the TMH was higher after the third and sixth TENS in both eyes (P = .03, P = .03 for right eyes respectively, P = .01, P = .01 for left eyes respectively). There was no significant difference between the adjusted Tetris scores before and during TENS (P = .12). The blink rate before and after TENS were unaffected after 6 sessions (P = .61). The results indicated that periorbital TENS effectively ameliorated ocular irritation and improved tear secretion and tear film stability by eliciting strong blinks in healthy VDT users without disturbing the visual task.

Video display terminal use and dry eye: preventive measures and future perspectives.

BACKGROUND: Dry eye disease (DED) is a common cause of ocular pain and discomfort. Dry eye disease (DED) stems from a loss-of-tear film homeostasis and is frequently seen in video display terminal (VDT) users. Video display terminal (VDT) use reduces blink rates and increases incomplete blinks, leading to tear film instability and ocular inflammation, promoting DED. PURPOSE: To assess and evaluate the methods for preventing VDT-associated DED and ocular discomfort. METHODS: Studies were found using PubMed and Embase with the search terms: (digital visual terminal* OR computer use OR screen use OR smartphone OR display OR visual display terminal* OR computer vision syndrome OR tablet OR phone OR screen time) AND (dry eye OR DED). RESULTS: Thirty-one relevant articles were found. Ten described single-visit studies, whereas 21 had a prolonged follow-up. Most preventive measures of VDT-associated DED aimed to increase blink rate or directly prevent tear film instability, ocular inflammation, mucin loss or ocular surface damage. Using an adjustable chair and ergonomic training, blink animations and omega-3 supplementation improved signs and symptoms of VDT-associated DED. Taking frequent breaks was associated with fewer symptoms, but no study assessed the commonly suggested 20-20-20 rule. CONCLUSION: Preventive measures, such as blink animation programmes, oral intake of omega-3 fatty acids and improved ergonomics act on different parts of the vicious cycle of dry eye and could supplement each other. A comparison of the efficacy of the different interventions as well as more evidence of the effect of increased humidity, VDT filters and ergonomic practices, are required.

A Pilot, Phase II, Observational, Case-Control, 1-Month Study on Asthenopia in Video Terminal Operators without Dry Eye: Contrast Sensitivity and Quality of Life before and after the Oral Consumption of a Fixed Combination of Zinc, L-Carnitine, Extract of Elderberry, Currant and Extract of Eleutherococcus.

The aims of the study were to investigate the ability and effectiveness of an oral intake of a fixed combination of zinc, L-carnitine, elderberry extract, black currant and Eleutherococcus extract in controlling the symptoms of eyestrain in videoterminal (VDT) users and to record its effects on contrast sensitivity. A single-center, phase II, observational, case-control, 1-month study in VDT workers without dry eye disease was carried out. Demographics and number of actual hours at VDT/day were taken into account. All subjects underwent a complete ophthalmic examination, including assessment of contrast sensitivity, and completed the computer vision symptom scale questionnaire at baseline and one month later. A total of 30 Caucasian subjects adhered to the required inclusion criteria and completed the study; 15 subjects were treated (T) and 15 were controls (C). All clinical data at baseline were similar in both groups (p > 0.05): after one month, all subjects had stable visual acuity, refractive defect and intraocular pressure (IOP); screen exposure time was unchanged. Regarding symptoms, at randomization, the groups had a similar score: 33.1 ± 3.3 in T and 32.8 ± 5.6 in C. One month later, the computer vision symptom scale (CVSS) questionnaire score decreased by -14.1 ± 3, 1 (p = 0.000) and -2.3 ± 1.8 (p = 0.568), respectively. Regarding contrast sensitivity, in group C the values of spatial frequencies remained unchanged, while they improved in almost all the cycles per degree stimuli in the treated group. Oral intake of a fixed combination of zinc, L-carnitine, elderberry extract, black currant and eleutherococcus extract can significantly improve contrast sensitivity and symptoms in VDT workers with no signs of dry eye disease.

Approach to Dry Eye in Video Display Terminal Workers (Basic Science).

The use of video display terminals (VDT) and staring at screens of technologic devices, including desktops, laptops, tablets, and smartphones have become ubiquitous in a wide range of age groups because of the rapid advance of network culture-mediated communications. The incidence of dry eye is particularly high in workers that work with VDT. To facilitate an understanding of the mechanisms of VDT-associated dry eye, as well as to develop novel treatment approaches, a VDT worker dry eye model was created. The procedure involved placing rats on a swing in combination with exposure to an evaporative environment. This animal model reveals that the blink frequency was reduced to one-third of the nonswing riding levels, which is similar to the results that have been reported by VDT users. Pathologic analysis of the lacrimal gland in this dry eye model showed that the decrease in tear secretion was accompanied by a decrease in the acinar cell number, and an enlargement of acinar cells was accompanied by filling with an increased volume of secretory vesicles and a loss of intracellular cell structure, suggesting the involvement of lacrimal hypofunction. An interventional study using this dry eye model showed that oral supplementation of some natural ingredients is a possible therapy for relieving symptoms of VDT-associated dry eye. Further investigations for the establishment of VDT use-associated dry eye models that may be used to evaluate ocular discomfort that mimic the condition in humans are needed to understand and modify this type of dry eye.

A Window Toward the World: Older Adults' Experiences of Becoming in Health and Developing as Human Beings Through Interacting With Others Using Real Video Communication.

The population in the Nordic countries, as well as globally, is increasingly becoming older. Concurrently, with an increased aging population, there is an increase in poor health and loneliness among older adults. The aim of this study was to uncover, from a caring science perspective, community-living older adults' experiences of interacting with others via real video communication. The study uses a hermeneutical approach. The material consists of interviews with older adults regarding their experiences of using real video communication. The texts were interpreted through hermeneutical reading. Study participation and data storage and handling for research purposes were approved by the participants when they provided their informed consent. Ethical permission to conduct this study was granted by a research board. The findings uncovered that welfare technology offers a metaphor-a window toward the world-that comprises the overarching core theme "Being in a movement toward becoming a unity as a human being," and 3 main themes: "Alleviating suffering through beating involuntary solitude," "Being in the world as an equal and dignified human being," and "Dedicating new perspectives and meaning in life." Welfare technology seems to be an important means to improve the quality of life for older adults living at home. Welfare technology enables older people to be in contact with other people in an easy way. Further research is needed to uncover issues of welfare technology from different perspectives.

[Bridge role of Jingming (BL 1) for VDT asthenopia and brainfag based on human instinct].

To explore the bridge role of Jingming (BL 1) for video display terminal (VDT) asthenopia and brainfag. Ancient literature and modern scientific research on the acupoint have been analyzed and summarized so as to explore pressing the acupoint the instinct feedback of brain after asthenopia. It is demonstrated that Jingming (BL 1) is a key channel between eyes, brain and the outside world, and it is one of major feedback points of brain after asthenopia. In this paper we try to establish a new research thinking and ascertain it, namely Jingming (BL 1) reflecting the relationship between asthenopia and brainfag. We hope that it can provide some references for further research on cognizing brain through eye.

[Efficacy on visual display terminal syndrome treated with jingjin therapy of Zhuang medicine].

OBJECTIVE: To observe the efficacy and explore the effect mechanism on visual display terminal syndrome treated with jingjin therapy of Zhuang medicine. METHODS: Sixty-five patients of visual fatigue induced by the visual display terminal operation were treated with jingjin trigeminy therapy of Zhuang medicine, e.g. massage manipulation, acupuncture and cupping; acting on the specific stimulating areas in Zhuang medicine, relevant with orbit, temple, forehead, ear and Baihui (GV 20). Each treatment lasted 40 min, once every two or three days. Totally, 10 to 14 treatments were required. The scores of visual symptoms and the ocular hemodynamics before and after treatment were observed, and clinical effect were evaluated in the two groups. RESULTS: After treatment, the scores of visual symptoms were reduced apparently as compared with those before treatment (all P<0.05). The total effective rate was 84.6% (55/65). The peak systolic velocity (PSV), the end diastolic velocity (EDV) in anterior ciliary artery (ACA) and the central retinal artery (CRA) were improved obviously, indicating the significant differences before and after treatment (all P<0.05). CONCLUSIONS: The jingjin therapy of Zhuang medicine alleviates the visual symptoms in patients of visual fatigue and improves visual quality. The effects are related to the improvement of ocular microcirculation.

Short-Term Omega 3 Fatty Acids Treatment for Dry Eye in Young and Middle-Aged Visual Display Terminal Users.

OBJECTIVE: To evaluate the effect of an omega 3 fatty acid (O3FA) oral supplement (2,400 mg/day) for 45 days on dry eye symptoms, tear production, stability, and conjunctival cytology in young and middle-aged visual display terminal (VDT) users. METHODS: Institutional review board approval was obtained, and a randomized, double-blind, interventional study was done; eyes of 256 VDT users were randomized to receive 4 capsules twice daily for 45 days (O3FA group), each containing 180 mg of eicosapentaenoic acid and 120 mg docosahexaenoic acid. The O3FA group was compared with another group (n=266) who received 8 capsules of a placebo (olive oil). Patients were evaluated at baseline, 30 days, and 45 days. The primary outcome measure was an improvement in dry eye symptoms. Secondary outcome measures were improvement in the Nelson grade on conjunctival impression cytology, Schirmer test values, and tear film breakup time (TBUT). Means of groups (pretreatment, day 30, and day 45) were compared with repeated-measure analysis of variance. The relation between the outcome variables and VDT time was evaluated using linear regression. RESULTS: In the O3FA group, the mean symptom score differed significantly (P<0.005) (pretreatment, 30 days, and 45 days); the TBUT and Nelson grade also improved significantly but only after 45 days of intervention. Schirmer test values did not differ significantly after adjustment for multiple comparisons (P=0.010). The change was not significant in the placebo group. CONCLUSION: Consumption of 2,400 mg/day of O3FA supplement improves symptoms, tear stability, and conjunctival cytology but not tear production in symptomatic VDT users.

Bilberry extract supplementation for preventing eye fatigue in video display terminal workers.

OBJECTIVES: To examine the effect of a dietary supplement containing bilberry extract (BE) on eye fatigue induced by acute video display terminal (VDT) loads. DESIGN AND SETTING: A prospective, randomized, double-blind, placebo-controlled study was performed from August 2012 to February 2013 in the Medical Corporation Jico-kai Yagi Hospital, and the Shinyokohama Shinoharaguchi Orthopedic Surgery and Dermatology Clinic, in Japan. PARTICIPANTS: Two hundred eighty-one office workers aged 20-40 years that used VDTs were screened by critical flicker fusion (CFF) and near point accommodation (NPA). INTERVENTION: The participants were randomized to either a BE (480 mg/day) or placebo (vehicle) group, and took allocated capsule, daily, for 8 weeks. MEASUREMENTS: The CFF, NPA, contrast visual acuity, functional visual acuity, keratoconjunctival epithelial damage, and fluorescein tear film break-up time were examined, and 18 subjective symptoms of eye fatigue were evaluated by questionnaire. Adverse events were reported via medical interviews. Data were collected both before and after VDT load at baseline, and 4, and 8 weeks after daily supplementation with either BE or placebo. RESULTS: Of 281 participants screened, 88 having relatively lower levels of CFF and NPA were enrolled in the study. Of these, 37 control and 43 BE group subjects completed the study. The VDT load-induced reduction in CFF was alleviated after 8 weeks of BE supplementation (95% confidence interval, 0.10-1.60; p=0.023), in contrast to placebo supplementation, while NPA variation was not. Of the subjective symptoms of eye fatigue, VDT load-induced ocular fatigue sensation, ocular pain, eye heaviness, uncomfortable sensation, and foreign body sensation were mitigated more in the BE group than in the control group, at week 8 (p<0.05). There were no severe adverse events in either group. CONCLUSIONS: BE supplementation improved some of the objective and subjective parameters of eye fatigue induced by VDT loads.

Tactile feedback display with spatial and temporal resolutions.

We report the electronic recording of the touch contact and pressure using an active matrix pressure sensor array made of transparent zinc oxide thin-film transistors and tactile feedback display using an array of diaphragm actuators made of an interpenetrating polymer elastomer network. Digital replay, editing and manipulation of the recorded touch events were demonstrated with both spatial and temporal resolutions. Analog reproduction of the force is also shown possible using the polymer actuators, despite of the high driving voltage. The ability to record, store, edit, and replay touch information adds an additional dimension to digital technologies and extends the capabilities of modern information exchange with the potential to revolutionize physical learning, social networking, e-commerce, robotics, gaming, medical and military applications.

Work-site health promotion of frequent computer users: comparing selected interventions.

OBJECTIVE: Frequent computer use is associated with an increase in musculoskeletal complaints. The present study aims at comparing the relative efficacy of three novel interventions for the preventions of musculoskeletal complaints in frequent computer users. PARTICIPANTS: 93 employees (56 woman, 37 men, mean age 40.1 ± 8.8 years) with frequent computer use. METHODS: Participants were assigned on the basis of preference to one of the following interventions of 8 week duration: Nordic Walking (NW), biofeedback assisted relaxation and stretching (BFB), balance exercises on a wobble board (BAL) or a waiting list control group. Outcome measures were musculoskeletal complaints, emotional well-being, fatigue, job dissatisfaction as well as neuromuscular activity in the neck/shoulder region at rest and during computer work assessed before and after the intervention and at 3 months follow-up. RESULTS: The average number of training-units per week was 2.2 ± 0.8, 5.5 ± 3.5 and 4.1 ± 2.9 for NW, BFB and BAL, respectively. NW led to short and medium term improvement of musculoskeletal complaints, BFB to a short term improvement of musculoskeletal complaints. Effects on the well-being related variables or on neuromuscular activity were not found. BAL had no effect on the studied variables. CONCLUSION: NW and to a limited extent BFB are interventions potentially useful for reducing musculoskeletal complaints in frequent computer users.

Cupping for treating neck pain in video display terminal (VDT) users: a randomized controlled pilot trial.

OBJECTIVES: This was a randomized controlled pilot trial to evaluate the effectiveness of cupping therapy for neck pain in video display terminal (VDT) workers. METHODS: Forty VDT workers with moderate to severe neck pain were recruited from May, 2011 to February, 2012. Participants were randomly allocated into one of the two interventions: 6 sessions of wet and dry cupping or heating pad application. The participants were offered an exercise program to perform during the participation period. A 0 to 100 numeric rating scale (NRS) for neck pain, measure yourself medical outcome profile 2 score (MYMOP2 score), cervical spine range of motion (C-spine ROM), neck disability index (NDI), the EuroQol health index (EQ-5D), short form stress response inventory (SRI-SF) and fatigue severity scale (FSS) were assessed at several points during a 7-week period. RESULTS: Compared with a heating pad, cupping was more effective in improving pain (adjusted NRS difference: -1.29 [95% CI -1.61, -0.97] at 3 weeks (p=0.025) and -1.16 [-1.48, -0.84] at 7 weeks (p=0.005)), neck function (adjusted NDI difference: -0.79 [-1.11, -0.47] at 3 (p=0.0039) and 7 weeks (p<0.0001)) and discomfort (adjusted MYMOP2 difference score: -0.72 [-1.04 to -0.40] at 3 weeks and -0.92 [-1.24, -0.60] at 7 weeks). Significant improvement in EQ-5D was observed at 7 weeks (1.0 [0.88, 1.0] with cupping and 0.91 [0.86, 0.91] with heating pad treatment, p=0.0054). Four participants reported mild adverse events of cupping. CONCLUSION: Two weeks of cupping therapy and an exercise program may be effective in reducing pain and improving neck function in VDT workers.

[Efficacy evaluation of acupoints massage on asthenopia of video display terminal under different exposure dose].

OBJECTIVE: To observe the efficacy differences of acupoints massage for asthenopia of video display terminal (VDT) under different exposure dose. METHODS: One hundred and two cases (204 eyes) were divided into a low exposure group and a high exposure group, fifty-one cases in each group. The same intervention of acupoints massage on Cuanzhu (BL 2), Jingming (BL 1), Sizhukong (TE 23), Sibai (ST 2) and Taiyang(EX-HN 5) were given to the two groups, one acupoint for 5 min and once everyday, one month of which made a course. The symptom score, tear film break-up time (BUT) and Schirmer I test(SIT) were observed before and after treatment. RESULTS: (1) The correlation coefficient of cubic curve model of the exposure dose was the biggest with symptom improvement index (P = 0.000), which indicated that the lower VDT exposure index was, the more obvious the symptom improved. The symptom improvement indices of low exposure group and high exposure group, which were (52.31 +/- 16.65)% and (28.93 +/- 13.35)% respectively, were statistical significant difference (P = 0.000). (2) Compared to before treatment, the levels of BUT and SIT in the two groups were both significantly higher (P < 0.05). Compared with the high exposure group, the levels of BUT and SIT in the low exposure group were increased by 0.826 s (P = 0.022) and 1.029 mm (P = 0.033), respectively, after the impact of BUT and SIT was corrected before the research. CONCLUSION: The acupoints massage can improve the symptoms and ocular physiology for patients with VDT asthenpia, and it is more effective for the low exposure cases.

Improvement of accommodation with anti-oxidant supplementation in visual display terminal users.

OBJECTIVE: To determine the antioxidant supplementation effect on accommodation among VDT users. DESIGN: A double blind randomized placebo controlled study. Registered under ClinicalTrials.gov Identifier No. NCT00877201. PARTICIPANTS AND CONTROLS: Fourty right eyes of 40 healthy VDT users (30 females, 10 males, mean age: 43.8±2.8 years, range: 40-49 years). 20 subjects (15 females, 5 males; mean age: 44.0±2.7 years, range: 40-49 years). METHODS: Subjects were required to take an antioxidant supplement, 20 age and sex matched subjects (15 females, 5 males; mean age: 43.6±3.1 years, range: 40-49 years) were required to take placebo medication for 4 weeks. RESULTS: The mean of the change in accommodation power was significantly higher in the group receiving antioxidant supplements (0.20±0.50 Diopter(D)) compared to the placebo group (-0.12±0.48(D)) (p<0.05). CONCLUSIONS: Antioxidant supplementation was observed to improve accommodation in Japanese Visual Display Terminal (VDT) Users.

Efficacy evaluation of acupoints massage on asthenopia of video display terminal under different exposure dose / 中国针灸

<p><b>OBJECTIVE</b>To observe the efficacy differences of acupoints massage for asthenopia of video display terminal (VDT) under different exposure dose.</p><p><b>METHODS</b>One hundred and two cases (204 eyes) were divided into a low exposure group and a high exposure group, fifty-one cases in each group. The same intervention of acupoints massage on Cuanzhu (BL 2), Jingming (BL 1), Sizhukong (TE 23), Sibai (ST 2) and Taiyang(EX-HN 5) were given to the two groups, one acupoint for 5 min and once everyday, one month of which made a course. The symptom score, tear film break-up time (BUT) and Schirmer I test(SIT) were observed before and after treatment.</p><p><b>RESULTS</b>(1) The correlation coefficient of cubic curve model of the exposure dose was the biggest with symptom improvement index (P = 0.000), which indicated that the lower VDT exposure index was, the more obvious the symptom improved. The symptom improvement indices of low exposure group and high exposure group, which were (52.31 +/- 16.65)% and (28.93 +/- 13.35)% respectively, were statistical significant difference (P = 0.000). (2) Compared to before treatment, the levels of BUT and SIT in the two groups were both significantly higher (P < 0.05). Compared with the high exposure group, the levels of BUT and SIT in the low exposure group were increased by 0.826 s (P = 0.022) and 1.029 mm (P = 0.033), respectively, after the impact of BUT and SIT was corrected before the research.</p><p><b>CONCLUSION</b>The acupoints massage can improve the symptoms and ocular physiology for patients with VDT asthenpia, and it is more effective for the low exposure cases.</p>

A comparison of two interventions designed to promote neutral wrist postures during simple computer operations.

OBJECTIVE: To compare two postural interventions, a wrist splint and a Wrist Alignment Device (WAD) with a biofeedback mechanism. PARTICIPANTS: Nine right-handed healthy individuals participated in the study. METHODS: Using both hands independently a 30-minute office-activity-experiment was performed that consisted of data entry, mouse clicking, text dragging, and mouse scrolling executed one after the other. Joint motion, tendon travel and productivity levels were measured. Participants wore a custom-made flexible electrogoniometric glove (FEG) as three scenarios were tested; namely FEG-only, FEG-Splint, and FEG-WAD. Data analysis was performed using descriptive statistics and ANOVA. RESULTS: The joint motion results produced insignificant differences (p>0.05) between hands. Both hands showed larger overall tendon travel for the FEG-only when compared with either FEG-Splint or FEG-WAD experiments. Wearing the splint reduced the overall tendon travel by 24% and 10% for the left and right hands while using the WAD further reduced the overall tendon travel for the left and right hands by 51% and 42%. Productivity levels were similar across participants with respect to experiment task and type. CONCLUSION: The WAD intervention is the most suitable device to promote a comfortable and non-restrictive neutral wrist posture.

Upper extremity rehabilitation of children with cerebral palsy using accelerometer feedback on a multitouch display.

Cerebral palsy is a non-progressive neurological disorder caused by disturbances to the developing brain. Physical and occupational therapy, if started at a young age, can help minimizing complications such as joint contractures, and can improve limb range of motion and coordination. While current forms of therapy for children with cerebral palsy are effective in minimizing symptoms, many children find them boring or repetitive. We have designed a system for use in upper-extremity rehabilitation sessions, making use of a multitouch display. The system allows children to be engaged in interactive gaming scenarios, while intensively performing desired exercises. It supports games which require completion of specific stretching or coordination exercises using one or both hands, as well as games which use physical, or "tangible" input mechanisms. To encourage correct posture during therapeutic exercises, we use a wireless kinematic sensor, worn on the patient's trunk, as a feedback channel for the games. The system went through several phases of design, incorporating input from observations of therapy and clinical sessions, as well as feedback from medical professionals. This paper describes the hardware platform, presents the design objectives derived from our iterative design phases and meetings with clinical personnel, discusses our current game designs and identifies areas of future work.

Aging affects the mental simulation/planning of the "rising from the floor" sequence.

We investigated the effect of aging on the ability to mentally simulate/plan a complex sequential action of the whole body, namely "rising from the floor". Forty-four non-demented elderly people (mean age: 85.2±5.5 years) and 20 young people (mean age: 26.6±4.9 years) were included in the study. They were required to put in order six images representing the main movements necessary to get up from a sitting position on the floor. We showed that older subjects had poorer performance-both in terms of proportion of success and response time-than their younger counterparts. These results are in line with previous findings showing age-related alterations in action simulation/action planning processes, and highlight the fact that elderly people have particular difficulties when the action to mentally simulate is complex.

A 12-week lutein supplementation improves visual function in Chinese people with long-term computer display light exposure.

We aimed to examine the effect of different doses of lutein supplementation on visual function in subjects with long-term computer display light exposure. Thirty-seven healthy subjects with long-term computer display light exposure ranging in age from 22 to 30 years were randomly assigned to one of three groups: Group L6 (6 mg lutein/d, n 12); Group L12 (12 mg lutein/d, n 13); and Group Placebo (maltodextrin placebo, n 12). Levels of serum lutein and visual performance indices such as visual acuity, contrast sensitivity and glare sensitivity were measured at weeks 0 and 12. After 12-week lutein supplementation, serum lutein concentrations of Groups L6 and L12 increased from 0.356 (SD 0.117) to 0.607 (SD 0.176) micromol/l, and from 0.328 (SD 0.120) to 0.733 (SD 0.354) micromol/l, respectively. No statistical changes from baseline were observed in uncorrected visual acuity and best-spectacle corrected visual acuity, whereas there was a trend toward increase in visual acuity in Group L12. Contrast sensitivity in Groups L6 and L12 increased with supplementation, and statistical significance was reached at most visual angles of Group L12. No significant change was observed in glare sensitivity over time. Visual function in healthy subjects who received the lutein supplement improved, especially in contrast sensitivity, suggesting that a higher intake of lutein may have beneficial effects on the visual performance.

Dose recalculation and the Dose-Guided Radiation Therapy (DGRT) process using megavoltage cone-beam CT.

PURPOSE: At the University of California San Francisco, daily or weekly three-dimensional images of patients in treatment position are acquired for image-guided radiation therapy. These images can be used for calculating the actual dose delivered to the patient during treatment. In this article, we present the process of performing dose recalculation on megavoltage cone-beam computed tomography images and discuss possible strategies for dose-guided radiation therapy (DGRT). MATERIALS AND METHODS: A dedicated workstation has been developed to incorporate the necessary elements of DGRT. Patient image correction (cupping, missing data artifacts), calibration, completion, recontouring, and dose recalculation are all implemented in the workstation. Tools for dose comparison are also included. Examples of image correction and dose analysis using 6 head-and-neck and 2 prostate patient datasets are presented to show possible tracking of interfraction dosimetric endpoint variation over the course of treatment. RESULTS: Analysis of the head-and-neck datasets shows that interfraction treatment doses vary compared with the planning dose for the organs at risk, with the mean parotid dose and spinal cord D(1) increasing by as much as 52% and 10%, respectively. Variation of the coverage to the target volumes was small, with an average D(5) dose difference of 1%. The prostate patient datasets revealed accurate dose coverage to the targeted prostate and varying interfraction dose distributions to the organs at risk. CONCLUSIONS: An effective workflow for the clinical implementation of DGRT has been established. With these techniques in place, future clinical developments in adaptive radiation therapy through daily or weekly dosimetric measurements of treatment day images are possible.