Simulating the Effects of Partial Neural Conduction Delays in the Visual Evoked Potential.

Purpose: The purpose of this study was to understand the double peaks or broadening of P100 observed in some cases of optic neuritis by inducing conduction delays in healthy eyes through stimulus luminance manipulation in analogy to the perceptual Pulfrich effect.

Methods: Checkerboard pattern reversal visual evoked potentials (VEPs) with check sizes of 0.8 degrees, 0.

[Global ophthalmology : Update].

The aim of global ophthalmology is to maximize vision, ocular health and functional ability, thereby contributing to overall health and well-being, social inclusion and quality of life of every individual worldwide. Currently, an estimated 1.1 billion people live with visual impairment, 90% of which can be prevented or cured through largely cost-effective interventions.

Simulation of visual impairment in persons with normal vision for scientific research.

Simulation of visual impairment in healthy eyes has multiple applications in students' training, research and product development. However, due to the absence of an existing standard protocol, the method of simulation was left to the discretion of the researcher. This review aimed to outline the various methods of simulating visual impairment and categorising them.

Central contrast sensitivity perimetry discriminates between glaucomatous and non-glaucomatous eyes.

Background: Glaucoma is an optic neuropathy which causes irreversible vision loss. Standard perimetry, which is essential for glaucoma diagnosis, can only detect glaucomatous visual filed loss when considerable structural damage has occurred. Contrast sensitivity is one of the visual function tests that is reduced in eyes with glaucoma.

The effect of filters and varying illumination on contrast sensitivity in eyes with moderate to severe visual impairment.

Purpose: To investigate the effect of filters and illumination on contrast sensitivity in persons with cataract, pseudophakia, maculopathy and glaucoma to provide a guide for eye care providers in low vision rehabilitation.

Materials And Methods: A within-subjects experimental design with a counter-balanced presentation technique was employed in this study. The contrast sensitivity of eyes with cataract, pseudophakia, maculopathy and glaucoma was measured with filters (no filter, yellow, pink and orange) combined with increasing illumination levels (100 lx, 300 lx, 700 lx and 1000 lx) using the SpotChecks™ contrast sensitivity chart.

Convergence insufficiency symptom survey (CISS) scores are predictive of severity and number of clinical signs of convergence insufficiency in young adult Africans.

Purpose: This study aimed to investigate the correlation between convergence insufficiency symptom survey (CISS) score and the signs of convergence insufficiency (CI) and to evaluate the sensitivity and specificity of the CISS to predict CI and ametropia among young adult university students.

Method: This prospective cross-sectional clinic-based study included 300 first year university students (mean age = 21.58 (SD ± 2.

Disability glare and nighttime driving performance among commercial drivers in Ghana.

Objective: Glare caused by the headlights of on-coming vehicles risk safe driving at night. The study aimed to determine the relationship between glare exposure and nighttime driving performance among commercial drivers in Ghana.

Methods: This cross-sectional study involved commercial drivers with complaints of nighttime driving difficulties (N = 80; mean age = 41.

Smartphone usage among people living with severe visual impairment and blindness.

Low vision care and rehabilitation is often limited by access to assistive devices, especially in low-resourced countries, due to their high cost and unavailability. Smartphones have the potential to serve as an alternative assistive device for people living with severe visual impairment and blindness (SVIB). This study aims to investigate the use of smartphones among people living with SVIB.

Epidemiology and visual outcomes of ocular injuries in a low resource country.

Background: Ocular injury is a major cause of ocular morbidity and unilateral visual impairment and represents a considerable public health concern especially in low resource societies.

Objective: To evaluate the epidemiology and visual outcomes of ocular injuries in southern Ghana.

Methods: A retrospective hospital-based case series was conducted.

Computed tomography estimation of the prevalence of neuro-ophthalmic injuries in head trauma patients seen in a tertiary health facility in Ghana.

Introduction: Prevalence of traumatic brain injury (TBI) is extremely high and potentially associated with severe incapacitating consequences. Literature reports that 90% of road traffic deaths and injuries including TBI occur in low and middle-income countries including Ghana. Computed Tomography (CT) scan is the imaging modality of choice for the initial assessment of the extent of head injury.

Normative Values of Retinal Nerve Fibre Layer Thickness and Optic Nerve Head Parameters and Their Association with Visual Function in an African Population.

Purpose: To determine normative values of retinal nerve fibre layer thickness (RNFL) and optic nerve head (ONH) parameters and their association with routine clinical tests such as refractive error (RE), stereoacuity (SA), and contrast sensitivity (CS) in an African population.

Methods: In a cross-sectional observational study, 100 normal subjects aged 20 to 78 years were evaluated using the Cirrus HD-OCT 5000 and matched with 200 glaucoma patients.

Results: Average (±SD) RNFL thickness for normal subjects was found to be 102.

Inter-regional trends in causes of childhood blindness and low vision in Ghana.

Background: Inter-regional trends of visual loss in most developing countries remain largely unknown. We compared the causes of childhood blindness among children attending blind schools in the northern (one school) and southern (two schools) regions of Ghana and assessed their need for spectacles and low-vision devices.

Methods: Using a standardised methodology, children were examined by an ophthalmologist and optometrists in each location.

The practise of paediatric optometry in a low-resource environment.

Background: The role of optometrists in paediatric visual assessment must compliment the role of other eye-care practitioners at all levels of care. This study was undertaken to determine if optometrists in Ghana screen, diagnose and manage paediatric ocular conditions (for example, strabismus, amblyopia), and further assessed if optometrists in Ghana have the requisite paediatric instrumentation in their practices.

Methods: This was a cross-sectional descriptive survey involving optometrists in both public and private eye-care sectors in Ghana.

Assessing the Progress towards Achieving "VISION 2020: The Right to Sight" Initiative in Ghana.

Purpose: The aim of this study was to analyse eye health delivery in Ghana and examine the progress towards achieving VISION 2020 indicator targets.

Methods: This descriptive cross-sectional study was conducted between October 2017 and May 2018. It used a mixed method approach including desk-based reviews, a questionnaire-based survey of eye facilities in Ghana, and interviews with eye health system stakeholders to collect information on eye health delivery in facilities owned by the Ghana Health Service (GHS), quasigovernmental bodies (security agencies), and Christian Association of Ghana (CHAG).

The Relationship Between the Photopic Negative Response and Retinal Ganglion Cell Topography.

Purpose: To assess the topographic relationship between the photopic negative response (PhNR) and retinal ganglion cell distribution in healthy individuals.

Method: Data was recorded from 16 healthy participants. The amplitude of PhNRs obtained in response to focal long duration (250 ms) and brief flash (5 ms), red (660 nm) on blue (469 nm) stimuli of increasing size (5° - full field) were measured.

Profile, knowledge, and attitude of contact lens users regarding contact lens wear in Ghana.

Background: Contact lenses are gaining popularity in developing countries as an alternative to spectacles for the correction of refractive errors. It is needful, therefore, to generate information to guide the mode of practice, and assist the industry in developing products for the increasing contact-lenses-user population. The purpose of this study was to identify the demographic profile, as well as the knowledge, attitude to wear and care regimen of wearers of contact lenses in Ghana.

Meibomian Gland Dysfunction in a Youthful Clinical Sample in Ghana.

Significance: This study showed a high frequency of nonobvious obstructive meibomian gland dysfunction, which can be detected only via the expression of the meibomian glands. The study advocates that meibomian gland expressibility should be a routine part of the clinical examination of patients especially those with dry eyes to avoid missing meibomian gland dysfunction among a youthful population.

Purpose: The aim of this study was to estimate the frequency of meibomian gland dysfunction including asymptomatic and symptomatic meibomian gland dysfunction and obvious and nonobvious obstructive meibomian gland dysfunction among a youthful population in Ghana.

Electrophysiological ON and OFF Responses in Autosomal Dominant Optic Atrophy.

Purpose: To assess the effect of autosomal dominant optic atrophy (ADOA) on ON and OFF retinal ganglion cell (RGC) function by evaluating the ON and OFF components of the photopic negative response (PhNR).

Methods: Twelve participants from six families with OPA1 ADOA and 16 age-matched controls were recruited. Electrophysiological assessment involved pattern ERGs (PERGs), focal (20°) and full-field long-duration (250 ms) flash ERGs using a red light-emitting diode flash on a rod-saturating blue background, and full-field brief (300 μs) xenon flash ERGs using a red filter over a continuous rod saturating blue background.