New advances in amblyopia therapy I: Binocular therapies and pharmacologic augmentation

Amblyopia therapy options have traditionally been limited to penalisation of the non-amblyopic eye with either patching or pharmaceutical penalisation. Solid evidence, mostly from the Pediatric Eye Disease Investigator Group, has validated both number of hours a day of patching and days per week of atropine use. The use of glasses alone has also been established as a good first-line therapy for both anisometropic and strabismic amblyopia. Unfortunately, visual acuity equalisation or even improvement is not always attainable with these methods. Additionally, non-compliance with prescribed therapies contributes to treatment failures, with data supporting difficulty adhering to full treatment sessions. Interest in alternative therapies for amblyopia treatment has long been a topic of interest among researchers and clinicians alike. Incorporating new technology with an understanding of the biological basis of amblyopia has led to enthusiasm for binocular treatment of amblyopia. Early work on perceptual learning as well as more recent enthusiasm for iPad-based dichoptic training have each generated interesting and promising data for vision improvement in amblyopes. Use of pharmaceutical augmentation of traditional therapies has also been investigated. Several different drugs with unique mechanisms of action are thought to be able to neurosensitise the brain and enhance responsiveness to amblyopia therapy. No new treatment has emerged from currently available evidence as superior to the traditional therapies in common practice today. But ongoing investigation into the use of both new technology and the understanding of the neural basis of amblyopia promises alternate or perhaps better cures in the future.</jats:p

Investigating the utility of clinical assessments to predict success with presbyopic contact lens correction

PURPOSE: To determine the utility of a range of clinical and non-clinical indicators to aid the initial selection of the optimum presbyopic contact lens. In addition, to assess whether lens preference was influenced by the visual performance compared to the other designs trialled (intra-subject) or compared to participants who preferred other designs (inter-subject). METHODS: A double-masked randomised crossover trial of Air Optix Aqua multifocal, PureVision 2 for Presbyopia, Acuvue OASYS for Presbyopia, Biofinity multifocal and monovision was conducted on 35 presbyopes (54.3±6.2years). Participant lifestyle, personality, pupil characteristics and aberrometry were assessed prior to lens fitting. After 4 weeks of wear, high and low contrast visual acuity (VA) under photopic and mesopic conditions, reading speed, Near Activity Visual Questionnaire (NAVQ) rating, subjective quality-of-vision scoring, defocus curves, stereopsis, halometry, aberrometry and ocular physiology were quantified. RESULTS: After trialling all the lenses, preference was mixed (n=12 Biofinity, n=10 monovision, n=7 Purevision, n=4 Air Optix Aqua, n=2 Oasys). Lens preference was not dependent on personality (F=1.182, p=0.323) or the hours spent working at near (p=0.535) or intermediate (p=0.759) distances. No intersubject or strong intrasubject relationships emerged between lens preference and reading speed, NAVQ rating, halo size, aberrometry or ocular physiology (p>0.05). CONCLUSIONS: Participant lifestyle and personality, ocular optics, contact lens visual performance and ocular physiology provided poor indicators of the preferred lens type after 4 weeks of wear. This is confounded by the wide range of task visual demands of presbyopes and the limited optical differences between current multifocal contact lens designs

Validity and usability of a virtual reality intraocular surgical simulator

Cataract surgery is one of the most common surgical procedures in Sweden and around 90 000 operations are made each year. An aging population with increased demands on quality of life and good visual acuity, has led to an increased rate of surgery and more surgeons needs to be trained. Training of new cataract surgeons is done on scarce wet-lab training but mainly on patients. Training is costly and complications are higher for new surgeons compared to experienced ones. In the airline industry simulators are used for training. Pilots have to prove competent before flying a new airplane. No such standards exist for new cataract surgeons. Surgical simulators have been used in other surgical fields for training and reports have shown that training has improved performance on real operations. The purpose of this work was to validate Eyesi, a surgical simulator for cataract surgery training, and analyze learning curves. Furthermore we set out to investigate whether factors like stereoacuity and sex would be important for performance in the simulator. Evidence for construct validity was found for cataract specific modules capsulorhexis, hydromaneuvers and phaco divide and conquer and for manipulating modules cataract navigation training, cataract forceps training and cataract cracking and chopping training. Analysis of learning curves showed significant improvement throughout training. Evidence for concurrent validity was established for the capsulorhexis module. For the hydromaneuvers and phaco modules, the innate simulator scoring could not distinguish surgical skill but discrimination was dependent on video based human scoring. Stereoacuity was found to correlate with performance on the simulator but there were large individual variations. An individual’s sex had no influence on performance. We have shown that Eyesi can differentiate cataract surgical skill and that naïve can train in the simulator and improve. Stereoacuity has an effect on performance but there were large individual variations. Simulation-based training has the potential to move the early learning curve out of the operating room

Towards Developing an Eye-tracker Based Virtual Reality Application for Supporting Vision Screening

Statistics from 2014 show that 35 to 75 percent of school age children suffer from some sort of vision problem. Of these children, around 25\% have normal visual acuity, however, their problems relate to low performance of their vision system. This low performance can be due to, e.g., eye musculature, nerve problems, cognitive problems etc. Such deficiencies may get worse as the person gets older, and it is important that we strive to treat these issues while the person afflicted is still young. Standardized vision control is performed on children at the age of 4 or 5 in most European countries. This screening can miss functional vision problems. The identification of these requires additional expertise and resources. By providing better aids supporting vision screening, we can help to catch problems that standardized screenings do not prioritize. A previously developed laptop application (C&amp;Look) managed to target certain aspects of the screening battery identifying oculomotor problems (OMDs), a usual functional vision problem. However, C&amp;Look's functionalities are limited by the size of the screen and the lack of depth, two important issues influencing how our vision functions. Separation of vision problems and the lack of focus from the test person is another not addressed issue, as there is currently no way to distinguish between these. This thesis addresses these issues by developing a Virtual Reality (VR) version of C&amp;Look with the possibility of identifying the lack of focus before measuring functional vision problems. Evaluation with a vision expert indicates that VR technology provides great promise for further assisting the current vision screening battery, however, focus was deemed too correlated with functional vision fatigue for an attention test to be used for separating the issues. User experience evaluation from seven possible end-users shows that the VR version of the screening application is considered usable compared to the original version. This process also helps to highlight the benefits and weaknesses of a transition from 2D to 3D. A simulated environment makes the process feel more like a real screening process which can increase participants' focus. A clear drawback is the limitation of head-mounted displays (HMDs) capability of measuring distances of the gaze, but also less confidence in results and worse performance. Creating a screening application is feasible in VR and can help cover more parts of the vision screening battery than a laptop application allows.Masteroppgave i Programutvikling samarbeid med HVLPROG399MAMN-PRO

User-centered Virtual Environment Assessment And Design For Cognitive Rehabilitation Applications

Virtual environment (VE) design for cognitive rehabilitation necessitates a new methodology to ensure the validity of the resulting rehabilitation assessment. We propose that benchmarking the VE system technology utilizing a user-centered approach should precede the VE construction. Further, user performance baselines should be measured throughout testing as a control for adaptive effects that may confound the metrics chosen to evaluate the rehabilitation treatment. To support these claims we present data obtained from two modules of a user-centered head-mounted display (HMD) assessment battery, specifically resolution visual acuity and stereoacuity. Resolution visual acuity and stereoacuity assessments provide information about the image quality achieved by an HMD based upon its unique system parameters. When applying a user-centered approach, we were able to quantify limitations in the VE system components (e.g., low microdisplay resolution) and separately point to user characteristics (e.g., changes in dark focus) that may introduce error in the evaluation of VE based rehabilitation protocols. Based on these results, we provide guidelines for calibrating and benchmarking HMDs. In addition, we discuss potential extensions of the assessment to address higher level usability issues. We intend to test the proposed framework within the Human Experience Modeler (HEM), a testbed created at the University of Central Florida to evaluate technologies that may enhance cognitive rehabilitation effectiveness. Preliminary results of a feasibility pilot study conducted with a memory impaired participant showed that the HEM provides the control and repeatability needed to conduct such technology comparisons. Further, the HEM affords the opportunity to integrate new brain imaging technologies (i.e., functional Near Infrared Imaging) to evaluate brain plasticity associated with VE based cognitive rehabilitation

Towards Developing an Immersive Virtual Reality Applications for Supporting Vision Screening – A User Study

Functional Vision Problems (FVPs) are problems related to eye musculature and/or eye coordination rather than visual acuity. Such problems are rarely diagonsed through standard vision control, and can get worse with age if not properly treated. However, a thorough vision screening of many requires enormous resources from society, which is not possible today. This paper illustrates current challenges to screen functional vision problems (FVPs) using immersive VR applications. For this, a laptop-based program for screening oculomotor difficulties (OMDs), which is a particular type of FVP, is transferred to a head-mounted display (HMD) with integrated eye-tracking technology (ET). The program records the participants' small eye movements via ETs, e.g., fixation stability, saccades, and smooth pursuits during task performance, and allows examining irregularities pointing to OMDs. The paper illustrates the iterative development of the immersive VR program based on continuous feedback from a vision expert. Data was collected from a vision expert and 7 end-users. The results include user experience and usability evaluation of the immersive VR program compared to the laptop version. It discusses the necessity for having vision expertise during specific faces of the development process and presents critical issues for further development of applications utilizing eye movements for more accurate support for vision screening, e.g., issues regarding measuring depth perception and hand-eye coordinatio

Haptic-Enhanced Learning in Preclinical Operative Dentistry

Background: Virtual reality haptic simulators represent a new paradigm in dental education that may potentially impact the rate and efficiency of basic skill acquisition, as well as pedagogically influence the various aspects of students’ preclinical experience. However, the evidence to support their efficiency and inform their implementation is still limited. Objectives: This thesis set out to empirically examine how haptic VR simulator (Simodont®) can enhance the preclinical dental education experience particularly in the context of operative dentistry. We specify 4 distinct research themes to explore, namely: simulator validity (face, content and predictive), human factors in 3D stereoscopic display, motor skill acquisition, and curriculum integration. Methods: Chapter 3 explores the face and content validity of Simodont® haptic dental simulator among a group of postgraduate dental students. Chapter 4 examines the predictive utility of Simodont® in predicting subsequent preclinical and clinical performance. The results indicate the potential utility of the simulator in predicting future clinical dental performance among undergraduate students. Chapter 5 investigates the role of stereopsis in dentistry from two different perspectives via two studies. Chapter 6 explores the effect of qualitatively different types of pedagogical feedback on the training, transfer and retention of basic manual dexterity dental skills. The results indicate that the acquisition and retention of basic dental motor skills in novice trainees is best optimised through a combination of instructor and visualdisplay VR-driven feedback. A pedagogical model for integration of haptic dental simulator into the dental curriculum has been proposed in Chapter 7. Conclusion: The findings from this thesis provide new insights into the utility of the haptic virtual reality simulator in undergraduate preclinical dental education. Haptic simulators have promising potential as a pedagogical tool in undergraduate dentistry that complements the existing simulation methods. Integration of haptic VR simulators into the dental curriculum has to be informed by sound pedagogical principles and mapped into specific learning objectives

Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study

In the last decade an increasing number of application fields, including medicine, geoscience and bio-chemistry, have expressed a need to visualise and interact with data that are inherently three-dimensional. Stereoscopic 3D technologies can offer a valid support for these operations thanks to the enhanced depth representation they can provide. However, there is still little understanding of how such technologies can be used effectively to support the performance of visual tasks based on accurate depth judgements. Existing studies do not provide a sound and complete explanation of the impact of different visual and technical factors on depth perception in stereoscopic 3D environments. This thesis presents a new interpretative and contextualised analysis of the vision science literature to clarify the role of di®erent visual cues on human depth perception in such environments. The analysis identifies luminance contrast, spatial frequency, colour, blur, transparency and depth constancies as influential visual factors for depth perception and provides the theoretical foundation for guidelines to support the performance of accurate stereoscopic depth tasks. A novel assessment framework is proposed and used to conduct an empirical study to evaluate the performance of four distinct classes of 3D display technologies. The results suggest that 3D displays are not interchangeable and that the depth representation provided can vary even between displays belonging to the same class. The study also shows that interleaved displays may suffer from a number of aliasing artifacts, which in turn may affect the amount of perceived depth. The outcomes of the analysis of the influential visual factors for depth perception and the empirical comparartive study are used to propose a novel universal 3D cursor prototype suitable to support depth-based tasks in stereoscopic 3D environments. The contribution includes a number of both qualitative and quantitative guidelines that aim to guarantee a correct perception of depth in stereoscopic 3D environments and that should be observed when designing a stereoscopic 3D cursor

Assessment of Visual Function Using Mobile Apps

With the advances in smartphone and tablet screens, as well as their processing power and software, mobile apps have been developed reporting to assess visual function. This review assessed those mobile apps that have been evaluated in the scientific literature to measure visual acuity, reading metrics, contrast sensitivity, stereoacuity, colour vision and visual fields; these constitute just a small percentage of the total number of mobile apps reporting to measure these metrics available for tablets and smartphones. In general, research suggests that most of the mobile apps evaluated can accurately mimic most traditionally paper-based tests of visual function, benefitting from more even illumination from the backlit screen and aspects such as multiple tests and versions (to minimise memorisation) being available on the same equipment. Some also utilise the in-built device sensors to monitor aspects such as working distance and screen tilt. As the consequences of incorrectly recording visual function and using this to inform clinical management are serious, clinicians must check on the validity of a mobile app before adopting it as part of clinical practice