Testing the viability of measuring intraocular pressure using soundwaves from a smartphone

Abstract Early detection of increasing values of intraocular pressure (IOP) due to glaucoma can prevent severe ocular diseases and ultimately, prevent loss of vision. Currently, the need for an accurate, mobile measurement of IOP that shows no correlation to central corneal thickness is unmet within the modern healthcare practices. There is a potential to utilize soundwaves as a mobile measurement method and therefore, the relationship between IOP and the reflection coefficient of sound waves is investigated. Simulations are conducted using COMSOL Multiphysics to provide theoretical confirmation of the worthiness of the experiment. An experiment is conducted to further investigate the relationship between the internal pressure of an object and its acoustic reflection coefficient. The experiment exploits the use of hydrostatic pressure to determine internal pressure, and the reflection coefficient is measured and analyzed. An initial experiment is conducted to identify the resonant frequency of the object and the optimal frequency for maximizing reflection. The experiment shows comprehensively that there is a relationship between the internal pressure of an object and its acoustic reflection coefficient, providing a confirmation of the theory that would allow mobile measurements of IOP to be conducted with the use of a smart phone

A case of bilateral self-induced keratoconus in a patient with tourette syndrome associated with compulsive eye rubbing: case report

<p>Abstract</p> <p>Background</p> <p>Tourette syndrome is a neurologic disorder that is characterized by repetitive muscle contractions that produce stereotyped movements or sounds. Approximately 50% of individuals with TS also exhibit obsessive-compulsive behaviors including eye rubbing. We report a case of bilateral self-induced keratoconus in a patient with TS, associated with compulsive eye rubbing.</p> <p>Case presentation</p> <p>A 35-year-old man was first seen in our clinic as an outpatient due to rapid deterioration of vision in his right eye associated with pain and tearing, over a period of one month. Slit lamp biomicroscopy of the right eye showed a central stromal scar due to corneal hydrops. Clinical examination and corneal topography of the left eye were normal. Six months later the patient developed corneal hydrops of his left eye. During the following examinations his vision continued to deteriorate in both eyes, while a central stromal scar was forming in his left cornea. Four years after the initial examination the patient's visual acuity was no light perception in the right eye and counting fingers at 33 cm in the left eye. His right eye was phthisic.</p> <p>Conclusions</p> <p>Our patient developed a rapidly progressing bilateral corneal ectasia and phthisis of his right eye during a time period of 4 years. This unusual pattern suggests that the patient's compulsive behavior compromised both of his corneas and led to bilateral keratoconus.</p

History and symptom taking in contact lens fitting and aftercare.

AIM: To appraise history and symptom taking for contact lens consultations, to determine current practice and to make recommendations for best practice. METHOD: The peer reviewed academic literature was reviewed and the results informed a survey completed by 256 eye care practitioners (ECPs) on their current practice and influences. RESULTS: The last eye-test date, last contact lens aftercare (for existing wearers) and reason for visit are key questions for most ECPs. Detailed use of contact lens questions are more commonly applied in aftercares than when refitting patients who have previously discontinued wear (87% vs 56% use), whereas questions on ocular and general history, medication and lifestyle were generally more commonly utilised for new patients than in aftercares (72% vs 50%). 75% of ECPs requested patients bring a list of their medication to appointments. Differential diagnosis questioning was thorough in most ECPs (87% of relevant questions asked). Attempts to optimise compliance included oral instruction (95% always) and written patient instructions (95% at least sometimes). Abbreviations were used by 39% of respondents (26% used ones provided by a professional body). CONCLUSION: There is scope for more consistency in history and symptom taking for contact lens consultations and recommendations are made

Genetic prediction of myopia: prospects and challenges

YesAppeals have been made for eye care professionals to start prescribing anti-myopia therapies as part of their routine management of myopic children. 1–3 These calls are fuelled by two key considerations. Firstly, that interventions to slow myopia progression have shown success in randomized controlled trials (RCTs) 4–7, and secondly, appreciation that the risk of sight-threatening complications rises dose-dependently with the level of myopia. 8,9 Notwithstanding existing gaps in knowledge regarding the efficacy of current treatments (see below), these considerations argue that myopia control interventions should be widely adopted, and that they should be instigated at an early age – especially in children most at risk – in order to reduce the final level of myopia. Therefore in managing a child with myopia, an eye care professional would have to decide not only which therapy to recommend, but at what age to start treatment. In this review we discuss the future role of genetic prediction in helping clinicians treat myopia.NIHR Senior Research Fellowship. Grant Number: SRF‐2015‐08‐00

Optimal methodology for lid wiper epitheliopathy identification

Purpose: Lid wiper epitheliopathy (LWE) is a clinical sign that has been associated with dry eye disease. This study used a semi-automated method to identify the effect of drop instillation and post-dye viewing time on the absorption of lissamine green (LG) and sodium fluorescein (NaFl) on the upper eyelid in order to ascertain the optimal identification for LWE assessment. Methods: In 37 participants with LWE, 1-drop of 1% LG (10 μL) was applied to the superior bulbar conjunctiva in the right eye, and photographs of the lid margin were taken 1, 3, and 5 min after instillation. Measurements were repeated in the same eye following instillations of 2-drops of 1% LG. The same procedures were followed for application of 2% NaFl (2 μL) to the left eye. Staining area was determined using software to detect and measure dye-stained images. Analysis used a linear mixed model with fixed effects of time, number of drops and their interaction. Results: For LG, multivariate analysis showed that time of drop instillation was significant (p = 0.0091) as was the area of staining in the 2-drop versus 1-drop condition (p < 0.0001). For NaFl, there was a significant effect of time (p < 0.0001), drops (p < 0.0001), and a time/drops interaction (p < 0.0134), suggesting that both time and number of drops are important. Conclusion: A single drop of dye is insufficient to reveal the full extent of LWE staining. A 2-drop instillation is recommended and observation is recommended between 1 and 5 min (LG) and between 3 and 5 min (NaFl)

An examination of the hypothesis that intraocular pressure elevation episodes can have prognostic significance in glaucoma suspects

The efficacy of intraocular pressure reduction in retarding the progression of glaucoma has been demonstrated. This review examines the potential for prognostic advantage for glaucoma suspects in reducing their optic nerve head exposure to elevated intraocular pressure associated with activities which have been shown to elevate intraocular pressure. In this observational study, patients examined at the Centre for Eye Health (University of New South Wales) with a diagnosis of glaucoma suspect were surveyed to determine their histories for participation in activities which are known to elevate intraocular pressure. The evidence regarding the pathological significance of these sources of elevation in susceptible patients was examined. Apart from the universality of sleep-related intraocular pressure elevations, the histories from 183 confirmed glaucoma suspects indicate a wide range and variation in frequency of participation in other intraocular pressure elevating activities. A reduction in exposure to elevated intraocular pressure may improve the prognosis for glaucoma suspects. Additional patient specific assessment of the results of this screening could provide an indication of the degree (frequency, intensity level and duration) of exposure to elevated intraocular pressure. Such information may provide the basis for improving a patient's prognosis by helping them to identify opportunities to reduce such exposure to elevated intraocular pressure. Any benefit of reduction of such exposure appears likely to be greater if activities which elevate intraocular pressure are of long duration, occur frequently, occur over a long period of time, and/or involve high levels of intraocular pressure elevation

Reactive oxygen species, oxidative stress, glaucoma and hyperbaric oxygen therapy

© 2017 Spanish General Council of Optometry This review examines the role of oxidative stress in damage to cells of the trabecular meshwork and associated impaired aqueous drainage as well as damage to retinal ganglion cells and associated visual field losses. Consideration is given to the interaction between vascular and mechanical explanations for pathological changes in glaucoma. For example, elevated intraocular pressure (IOP) forces may contribute to ischaemia but there is increasing evidence that altered blood flow in a wider sense is also involved. Both vascular and mechanical theories are involved through fluctuations in intraocular pressure and dysregulation of blood flow. Retinal function is very sensitive to changes in haemoglobin oxygen concentration and the associated variations in the production of reactive oxygen species. Reperfusion injury and production of reactive oxygen species occurs when IOP is elevated or blood pressure is low and beyond the capacity for blood flow autoregulation to maintain appropriate oxygen concentration. Activities such as those associated with postural changes, muscular effort, eye wiping and rubbing which cause IOP fluctuation, may have significant vascular, mechanical, reperfusion and oxidative stress consequences. Hyperbaric oxygen therapy exposes the eye to increased oxygen concentration and the risk of oxidative damage in susceptible individuals. However, oxygen concentration in aqueous humour, and the risk of damage to trabecular meshwork cells may be greater if hyperbaric oxygen is delivered by a hood which exposes the anterior ocular surface to higher than normal oxygen levels. Oronasal mask delivery of hyperbaric oxygen therapy appears to be indicated in these cases