Frequency of Non-strabismic Binocular Vision Anomalies among Optometrists in a Tertiary Eye Care Center in Southern India.

Purpose: Lifestyle in the modern era has drastically changed across the globe, and the healthcare profession was no exception. The increased time spent in the virtual space for various purposes, including online classes and webinars, is hypothesized to increase the risk of vision-related disorders such as asthenopia, dry eyes, and visual fatigue. The purpose of this study was to evaluate fusional vergence and ocular accommodation among optometry professionals in a tertiary eye care center during the immediate post-coronavirus disease 2019 (post-COVID-19) lockdown period. Methods: Optometrists posted in the general out-patient department, specialty clinics, and the ocular diagnostics department were included in the study. A total of 65 optometrists were included in the study. All optometrists underwent a comprehensive binocular vision assessment. Convergence Insufficiency Symptom Survey questionnaires were administered to all optometrists at the beginning of the assessment. Results: Out of 65 optometrists, 48 (73.8%) were women. The mean (standard deviation) age of the participants was 24 (3) years. Eleven (16.9%) optometrists had normal binocular vision parameters, and the rest 54 (83.1%) had non-strabismic binocular vision anomalies. Reduced accommodative facility and convergence insufficiency were seen among 43 (66.2%) optometrists, whereas 30 (46.2%) had reduced accommodative facility alone. Twelve (18.5%) participants were symptomatic as per the convergence insufficiency symptom survey. Conclusion: This study highlights the fact that a large proportion of optometrists have undetected non-strabismic binocular vision anomalies in a tertiary eye care center. It is important for eye care professionals to undergo regular binocular vision assessments in association with ophthalmic examinations and relevant management. This will ensure that these dysfunctions do not impede work productivity and overall quality of life.

Dynamic correction of astigmatism.

For the correction of defocus and astigmatism, mechanical approaches are well known, but there is a need for a non-mechanical, electrically tunable optical system that could provide both focus and astigmatism power correction with an adjustable axis. The optical system presented here is composed of three liquid-crystal-based tunable cylindrical lenses that are simple, low cost, and having a compact structure. Potential applications of the concept device include smart eyeglasses, virtual reality (VR)/ augmented reality (AR) head-mounted displays (HMDs), and optical systems subject to thermal or mechanical distortion. Details of the concept, design method, numerical computer simulations of the proposed device, as well as characterization of a prototype, are provided in this work.

Diagnosis and Management of Post Traumatic Recurrent Unilateral Accommodative Spasm-A Case Report.

Spasm of accommodation refers to constant contraction of the ciliary muscles of the eye, which fail to relax. Neurological issues, head injury, and psychogenic factors can lead to spasm of accommodation, which is generally bilateral. This case report describes the clinical presentation of traumatic, unilateral accommodative spasm in an army person. A 26-year-old male presented with complaints of diminution of near vision in the left eye noticed accidentally. History revealed a blunt injury in the eyebrow region of the left eye two months back. His best corrected visual acuity was 6/6, 0.8 M (N6) in the right eye and 6/9, 2.5 M (N18) in the left eye. Accommodative response was documented using an open-field autorefractometer that showed asymmetry in the accommodation response and pupillary diameter between the two eyes. One percent Atropine sulfate eye ointment - twice a day for 3 days - was prescribed. On the fourth day, the spasm was resolved in the left eye. Pre- and post-Atropine administration, lens thickness measurements were documented, which showed significant changes. Accommodative facility exercise was initiated after the pharmacological management. Unilateral accommodative spasm is rare and needs careful investigations. Objective assessment of accommodative response and lens thickness measurement play a vital role in confirming the diagnosis.

Large area liquid crystal lenses for correction of presbyopia.

Presbyopia is the failure of the eye lens to accommodate. The widely used presbyopia correction method involves wearing bi/trifocal or progressive glasses, which limits the field of view due to division of lens area into sections of different optical power. A large aperture focus tunable liquid crystal lens has the potential to correct human eye accommodation failure and provide a wide field of view. In this paper, we present characterization and demonstration of a segmented phase profile liquid crystal lens, which has the characteristics of a large area (diameter: 20 mm), being flat and thin (<2 mm), and having continuous focus tunability (1.5 D to 0 D), fast response time (<500 ms), low operating voltage (<5 V), and on-axis diffraction-limited performance (for a 5mm aperture). Considering all these properties, our lens provides performance details of an approach for presbyopia correction. We have tested the minimum resolution and visual acuity of 20 subjects using the designed lens and compared the results with a reference glass lens of the same optical power.