[Global ophthalmology : Update]. / Globale Ophthalmologie : Aktueller Stand.

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. At the same time, 90% of people affected live in regions with insufficient eye health coverage. This challenge drove the World Health Organization (WHO) and a group of nongovernmental organizations to launch "VISION 2020: the Right to Sight", a global campaign which recently concluded after 20 years. The achievements, challenges and lessons learned were identified and incorporated into the current campaign "2030 IN SIGHT".

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, 0.4 degrees, and 0.2 degrees were recorded in healthy participants using two experiment variants. Variant (1) involved binocular stimulation with inter-ocular luminance difference achieved by a 1.8 neutral density (ND) filter, along with monocular control conditions. Variant (2) included monocular stimulation with hemifields having a luminance difference (half of monitor with ND filter), along with single-hemifield control conditions. In both variants, VEP curves under mixed stimulation were compared to synthesized VEPs computed from offline summation of curves from the relevant control conditions, followed by assessing P100 characteristics. Results: Despite considerable variability between participants, the binocular variant demonstrated marked differences between VEPs from mixed recordings and synthesized curves, whereas in the hemifield variant, agreement was strong. The anticipated double peak or broadened deflection pattern was observed to varying extents in participants, often contingent on check size, with nominal peak time frequently failing to indicate partial conduction delays. Conclusions: The present findings corroborate the hypothesis that nominal peak time does not always reflect conduction delays if only a subset of fiber bundles is affected. Peak shape might provide additional diagnostic evidence of a partial conduction delay. Translational Relevance: Enhancing the understanding of VEP waveform changes associated with partial conduction delays could offer diagnostic insights for optic neuritis.

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. A scoping review of the relevant publications was conducted. Of the 1593 articles originally retrieved from the databases, 103 were included in the review. The characteristics of the participants, the method for simulation of the visual impairment in persons with normal vision and the level or type of visual impairment that was simulated were extracted from the papers. None of the methods of simulation can be judged as being superior to the others. However, electronic displays produced the most consistent form of visual impairment simulation.

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. It is known to be affected in pre-perimetric stages of glaucoma. Objective: The objective of this study was to investigate the discriminating ability of central contrast sensitivity perimetry in eyes with and without glaucoma. Design: The study employed a cross-sectional study design. Methods: The study participants were made of two groups; eyes diagnosed with glaucoma by an ophthalmologist based on visual field test and optical coherence tomography (OCT) and age- and sex-matched controls who were declared free from glaucoma. Static contrast sensitivity (CS) was measured in the central 10° of visual field using a custom psychophysical test. Results: There were 45 eyes with glaucoma and 45 age- and sex-matched controls in this study. The static CS in the glaucoma group was significantly reduced in 9 out of the 13 tested locations in the central 10° of the visual field. The mean static CS at 5°, 10°, superior hemifield and inferior hemifield were all significantly reduced in the glaucoma patients compared to the controls. Conclusion: Static CS measurement is a sensitive approach that can be utilized to aid in the detection of glaucoma. The use of static CS can be adopted in the development of a cost-effective yet sensitive screening tool for the detection of 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. The data were analyzed using descriptive statistics and two-way repeated measures ANOVA. RESULTS: The yellow filter at 100 lx significantly improved contrast sensitivity in the maculopathy group. There were no significant improvements with either intervention in the rest of the groups. There was, however, a significant interaction between filters and illumination in the cataract group. CONCLUSION: There were small improvements in contrast sensitivity at low illumination levels with the yellow filter in the maculopathy group, and this could be considered in clinical practice and low vision rehabilitation. Overall, filters at most illumination levels did not benefit most groups.

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 ± 2.2) years) who consecutively reported for eye examination. Participants were administered the CISS questionnaire and investigated for the signs of CI. Diagnosis of CI was based on presence of three or four signs. The correlation between the CISS score and the signs of CI were determined and Receiver Operation Characteristics (ROC) curves were used to evaluate sensitivity and specificity.Results: There were significant correlations between CISS score and the clinical signs of CI namely NPC break (rs = 0.622, p = 0.0001), NPC recovery (rs = 0.620, p = 0.0001), near exophoria (rs = 0.434, p = 0.0001), near PFV blur (rs = -0.359, p = 0.0001), near PFV break (-0.306, p = 0.0001), near PFV recovery (rs = -0.326, p = 0.0001) and gradient AC/A ratio (rs = -0.290, p = 0.0001). There was a significant positive correlation between CISS score and the number of clinical signs of CI (rs = 0.575, p-value = 0.0001). The CISS had good sensitivity (AOC = 0.882) to predict CI and poor sensitivity (AOC = 0.642) to predict ametropia.Conclusion: The CISS score is correlated with the severity and number of signs of CI in young adult Ghanaian university students. Its use in addition to clinical investigative testing may give a definitive diagnosis of symptomatic CI. (AU)

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 ± 2.2) years) who consecutively reported for eye examination. Participants were administered the CISS questionnaire and investigated for the signs of CI. Diagnosis of CI was based on presence of three or four signs. The correlation between the CISS score and the signs of CI were determined and Receiver Operation Characteristics (ROC) curves were used to evaluate sensitivity and specificity. RESULTS: There were significant correlations between CISS score and the clinical signs of CI namely NPC break (rs = 0.622, p = 0.0001), NPC recovery (rs = 0.620, p = 0.0001), near exophoria (rs = 0.434, p = 0.0001), near PFV blur (rs = -0.359, p = 0.0001), near PFV break (-0.306, p = 0.0001), near PFV recovery (rs = -0.326, p = 0.0001) and gradient AC/A ratio (rs = -0.290, p = 0.0001). There was a significant positive correlation between CISS score and the number of clinical signs of CI (rs = 0.575, p-value = 0.0001). The CISS had good sensitivity (AOC = 0.882) to predict CI and poor sensitivity (AOC = 0.642) to predict ametropia. CONCLUSION: The CISS score is correlated with the severity and number of signs of CI in young adult Ghanaian university students. Its use in addition to clinical investigative testing may give a definitive diagnosis of symptomatic CI.

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. The study was a cross-sectional study of 166 people living with SVIB in a low resourced setting. The participants were recruited from two tertiary institutions and four eye care facilities. A questionnaire was administered to all respondents and for those who could not read prints they were read out to them and their responses recorded. The majority of respondents (n = 88, 53.1%) either had no phone or used a basic phone. The prevalence of smartphone usage among people living with SVIB was found to be 46.90% (n = 78). Most respondents use their smartphones to interact on social media [n = 75 (96%)] and web browsing [n = 69,92%]. The most frequently demanded [n = 22 (44%)] smartphone functionality by the respondents was the image and color description feature. Most participants were unaware that 90% of their functionality demands already existed and were compatible with current smartphones. A significant number of people living with SVIB in this study used smartphones; however, most users are unaware of its full functionality and assistive capabilities.

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 = 41.5 ± 11.1 years). A questionnaire was used to investigate nighttime driving performance following glare exposure. We measured contrast sensitivity and visual acuity under photopic conditions. With an experimental setup in a mesopic setting, we measured visual acuity with and without glare exposure. The difference between the two mesopic visual acuities was quantified as disability glare index. With the same setup, photostress recovery time was also measured. Regression analyses were used to determine the relationship between nighttime driving performance score and the measures taken in both photopic and mesopic settings. RESULTS: The average nighttime driving performance score was 47.8 ± 17.5. Driving performance was negatively correlated with all variables (R = -0.87 to -0.30, all p < .01), except contrast sensitivity (R = 0.74, p < .01). A multiple linear regression showed that the model with all variables explained 83.8% of the variance, but only disability glare index was a significant predictor of nighttime driving performance following glare exposure (standardized B = -0.61, p < .01). CONCLUSION: Our results show that the change in mesopic visual acuities following glare can predict nighttime driving performance. This measure can be incorporated into the assessment of driving fitness by licensing departments to evaluate whether a person can drive safely at night amidst glare exposure.

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. Information on new cases of ocular injuries were retrieved and parameters including time between injury occurrence and reporting to the clinic, presenting visual acuity (VA), and the best corrected final VA were investigated and visual outcomes were assessed Results: Most (50.2%) of the patients reported to the hospital after a day of sustaining an ocular injury; workplace injuries, older patients and farm-related injuries were most likely to report after a day of sustaining an injury. A significant proportion (40.4%) of patients reported with good presenting vision (6/6-6/18) which increased to 56.7% after treatment; 45.3% of patients reported with visual impairment (<6/18) and reduced to 42.4% after treatment. Farming (AOR = 4.5, p = 0.02), reporting after a day of sustaining injury (AOR = 78, p< 0.001), workplace injuries (AOR = 3.1, p = 0.007) and roadside injuries (AOR = 3.1, p = 0.02) were associated with poor visual outcomes. Initial VA 6/18 or better was the highest predictor of good visual outcome. CONCLUSION: There is a shift in the pattern of ocular injury occurrence from work-related to home- related.

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. Some Neuro-ophthalmic injuries (NOI) may sometimes be ambiguous and indistinct although a serious injury with potential damaging consequences. Data on the prevalence of NOI post trauma is non-existent in Ghana to inform policy. The onus therefore lies on the Radiologist who will review the head CT scan to be very meticulous not to miss any NOI if present. We therefore decided to diligently review a large cross-sectional retrospective post trauma head CT scans for occurrence of NOI. OBJECTIVE: To determine the incidence of NOI secondary to head trauma and the possible loss of vision thereof in a retrospective study using patients' head CT scan data from a tertiary hospital's CT centre in Cape Coast, Ghana. METHOD: All head CT scans secondary to trauma for the period January 2016 to December 2018, were retrieved and carefully analysed. A total number of 1043 of head CT scan images were analyzed by Consultant Radiologists. RESULTS: Results showed out of 1043 CT scans reviewed, 742 (71,1%) were males and 301 (28.9%) were females. A total of 609 (58.4%) out of the 1043 patients sustained NOIs of various anatomical types. More Males 398 (65.4%) sustained NOI than females 211 (34.6%). The incidence of NOI was more among the youth as majority 167 (27.4%) of the patients were within the 18-29 years followed by 30-39 years bracket of 148 (24.3%). Fourteen anatomical types of NOI were elicited and further analysis revealed, intra-ocular foreign body to be the highest 107 (17.6%) cases, orbital floor fractures injury was 92 (15.1%) cases, with globe rupture injury and intraocular hemorrhage recording 79 (13.0%) cases each. Optic nerve injury was the least revealing 7 (1.1%) cases. There was a relationship between the gender of patient and the propensity to sustain NOI as males were more disposed to NOI than females. Road traffic accident (RTA) was the main pervasive cause of TBI and this accounted for 71.9% of all cases, followed by fall from height 24%, and the least cause of TBI was ascribed to gunshot injury of 0.33%. CONCLUSION: Prevalence of NOI is high. Urgent measures must therefore be implemented to reduce the RTA menace in general and to mitigate the associated NOI and possible loss of vision thereof.

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 102.37 ± 7.45 (range, 82-119 microns) compared with 90.74 ± 14.50 found for glaucoma subjects. Females had higher average RNFL values (104.84 ± 6.90) compared with males (99.80 ± 7.18). Significant associations were calculated between quadrant RNFL thickness and SA, SE, and CS (all p < 0.05). The mean cup to disc ratio (CDR) was 0.49 ± 0.12, and mean optic disc area (DA) was 2.08 mm2 ± 0.40. Smaller DA was recorded for participants aged 60+ years (1.86 ± 0.25), followed by 40-59 age group (2.01 ± 0.41) and then 20-39 age group (2.19 ± 0.41). Significant associations were calculated between SA and ONH parameters, except rim area (all p < 0.05). The mean cup to disc ratio (CDR) was 0.49 ± 0.12, and mean optic disc area (DA) was 2.08 mm2 ± 0.40. Smaller DA was recorded for participants aged 60+ years (1.86 ± 0.25), followed by 40-59 age group (2.01 ± 0.41) and then 20-39 age group (2.19 ± 0.41). Significant associations were calculated between SA and ONH parameters, except rim area (all p < 0.05). The mean cup to disc ratio (CDR) was 0.49 ± 0.12, and mean optic disc area (DA) was 2.08 mm2 ± 0.40. Smaller DA was recorded for participants aged 60+ years (1.86 ± 0.25), followed by 40-59 age group (2.01 ± 0.41) and then 20-39 age group (2.19 ± 0.41). Significant associations were calculated between SA and ONH parameters, except rim area (all. CONCLUSION: RNFL thickness in healthy black Ghanaian population was significantly higher than that reported in other races. The values and associations reported in this study can inform clinical decision on the normal variation in RNFL and optic disc parameters.

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. Causes of visual loss were classified anatomically and by time of onset, and avoidable causes identified. Children identified with functional low vision were assessed and provided with low-vision devices. RESULTS: A total of 252 children under 16 years of age were examined in the schools. The overall prevalence of total blindness was 73 (29.0 per cent), with similar proportions (p = 0.87) in the north (29 [28.4 per cent]) and south (44 [29.3 per cent]); 92 (36.5 per cent) had functional low vision. Two children improved with spectacles and 35 benefited from low-vision devices. Corneal scarring was significantly (p = 0.045) more prevalent in southern Ghana (n = 150) than in the north (n = 102), responsible for visual loss in 36 (24.0 per cent, 95% CI 17.2-30.8 per cent) and 14 (13.7 per cent, 95% CI 7.0-20.4 per cent) cases, respectively. No significant difference (p = 0.321) was observed in the prevalence of cataract between northern (28: 27.5 per cent, 95% CI 18.3-36.2 per cent) and southern Ghana (33: 22.0 per cent, 95% CI 15.4-28.6 per cent). Over 87 per cent of children had 'avoidable' causes of visual loss, with a higher proportion being treatable (124: 49.2 per cent) than preventable (96: 38 per cent). CONCLUSION: Cataract was the major cause of visual loss in the overall population. The south had a higher proportion of corneal scarring and late-onset blindness compared with the north. More than one-third of blindness in blind schools in Ghana could have been prevented by primary care interventions and nearly half could have been treated surgically to prevent visual loss. Two in five children in blind schools in Ghana could benefit from optical intervention.

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. A paediatric visual assessment questionnaire was sent to all registered optometrists in Ghana. The contents of the questionnaire evaluated areas of vision assessment, refraction, and previous diagnosis and management, which were matched with practice characteristics such as location, type of practice and type of employment. Chi-squared statistic was used to test associations between variables. RESULTS: Responses were obtained from 140 optometrists out of the 326 registered optometrists, representing a response rate of 46 per cent. Overall, less than half of respondents (64 which represents 46 per cent) assessed themselves as practising full-scope paediatric eye care. These self-assessment views were more common among optometrists at the regional level (111: 79.3 per cent), followed by the district (20: 14.3 per cent) and sub-district levels (nine: 6.4 per cent) (χ2 = 4.774, p < 0.05), but was not influenced by type of employment, type of practice and level of training (p > 0.05). In addition, the study revealed that many respondents were more likely to assess pre-schoolers' visual acuity (VA) (121: 96.0 per cent), do refraction (109: 88.6 per cent) and perform binocular vision (BV) assessment (93: 76.9 per cent) compared to the toddlers' VA (72: 55.4 per cent), refraction (57: 46 per cent) and BV assessment (68: 56.2 per cent). CONCLUSION: Full-scope paediatric eye care services among optometrists in Ghana is limited.

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 information was benchmarked against the World Health Organization (WHO) targets for achieving the goals of VISION 2020. Results: The magnitude of blindness and moderate to severe visual impairment (without pinhole) was 0.9% and 3.0%, respectively. The number of ophthalmologists available at the country level was 80.6% of the VISION 2020 target with optometrists and ophthalmic nurses exceeding targets for VISION 2020. The distribution of human resources was heavily skewed towards two out of the 10 regions in Ghana. Cataract surgical rate was low and met 25% of the WHO target. Basic equipment for refraction was available in the majority of facilities; however, there was a general lack of specialised eye care equipment across the country. Comparatively, CHAG facilities were better equipped than GHS facilities at the same level. Conclusion: The Government of Ghana should revitalize the goals of VISION 2020 beyond the year 2020 and spearhead a concerted effort to ensure equitable distribution of human and infrastructural resources across the country.

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. The number of retinal ganglion cell receptive fields (RGCf) in each stimulus area was established from the literature and regression analysis used to determine the relationships between: PhNR amplitude and number of RGCfs stimulated, PhNR density and the RGCf density and response per RGCf as a function of eccentricity. Results: The overall amplitude of the PhNR increased with stimulus size and the response density declined from ∼0.1 µV/deg in the macular region to ∼0.003 µV/deg approximately 45° from the fovea. Contrary to expectations, the relationship between the PhNR and number of RGCf was nonlinear, the response from more eccentric neurons being about three times greater than those in the macular region. Conclusions: Although the amplitude of the PhNR broadly maps on to the topographic distribution of RGCf the increase in PhNR amplitude with increasing eccentricity is only partly explained by RGCf numbers. Increases in the PhNR amplitude may be due to topographic variations in the contributions from other non-RGC neurons, as well as eccentricity-related morphologic and physiologic differences in RGCs.

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. METHODS: In a cross-sectional study, case folders of 87 users of contact lenses were selected from the database eye contact lenses practices. The folders were reviewed for the demographic profile, type, and purpose for which the contact lenses were prescribed. Forty-two (42) contact lenses users were then randomly surveyed, using a semi-structured questionnaire to collect information on their knowledge, lens wear regimen, and attitudes regarding lens hygiene. Chi-square test was used to test associations between demographics and lens wear variables. RESULTS: Out of the 87 cases reviewed, 46 (52.9%) were females and 41 (47.1%) males. Their ages ranged from 15 to 68 years with a mean age of 28.62 ± 9.38 years. The majority- 65 (75%) - were youthful (≤ 40 years), with the highest proportion of them - 46 (53%) - being between 20-29 years. The majority - 60 (68.9%) - had a tertiary level of education. Soft contact lenses were commonly worn by 68 (78.2%) users while 19 (21.8%) wore rigid gas permeable lenses. The purpose for wearing contact lenses included for vision correction - 46 (52.9%), followed by for cosmesis - 23 (26.4%) - and therapeutic reasons -18 (20.7%). The commonest refractive error corrected was myopia - 38 (43.7%), followed by astigmatism -19 (21.8%) and hyperopia 6 (6.9%). Among the 42 users who responded to the questionnaire, by proportion, the majority -17 users (40.5%) - were introduced to contact lenses by optometrists. All respondents reported previous symptoms associated with the use of their contact lenses, but slightly more than half, 25 (57.1%) did yearly follow-up visits. CONCLUSION: The majority of contact lenses used in Ghana are soft lenses, for the purpose of vision correction. The use of contact lenses was common among individuals in their early adulthood and those with tertiary education.

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. METHODS: This was a clinic-based prospective cross-sectional study of consecutive patients visiting the University of Cape Coast Optometric clinic for comprehensive eye examination. RESULTS: Two hundred fifteen clinical subjects consented to participate in the study. Mean age of the entire sample was 21.9 (±3.8) years with an age range of 17 to 40 years. One hundred five males and 107 females participated. Frequency of meibomian gland dysfunction among the sample was 25.5% (95% confidence interval [CI], 19.8 to 31.6%). Frequencies of asymptomatic and symptomatic meibomian gland dysfunction were 10.1% and 15.4%, respectively. Frequencies of obvious and nonobvious obstructive meibomian gland dysfunction were 0.9% and 24.6%, respectively. In univariate logistic regression analysis, age (odds ratio, 1.246; 95% CI, 1.037 to 1.496; P = .019) was significantly associated, but sex (odds ratio, 1.315; 95% CI, 0.707 to 2.446; P = .387) was not significantly associated, with meibomian gland dysfunction. There was a statistically significant difference in the mean corneal staining scores between meibomian gland dysfunction subjects and non-meibomian gland dysfunction subjects (t = 3.51, P = .01). There was also a statistically significant difference in the mean tear breakup time between meibomian gland dysfunction subjects and non-meibomian gland dysfunction subjects (t = 4.44, P < .001). CONCLUSIONS: Because of the high frequency of nonobvious obstructive meibomian gland dysfunction, reliance on overt posterior lid margin abnormalities for the diagnosis of meibomian gland dysfunction may lead to underdiagnosis of meibomian gland dysfunction among clinicians in a youthful population.

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. Amplitudes and implicit times of the ERG components were analyzed and the diagnostic potential of each electrophysiological technique was determined by generating receiver operating characteristic (ROC) curves. RESULTS: Mean amplitudes of the N95 and all PhNRs, except the full-field PhNRON, were significantly reduced in participants with ADOA (P < 0.01). Subtraction of the group-averaged focal ERG of ADOA participants from that of controls showed an equal loss in the focal PhNRON and PhNROFF components, whereas in the full-field ERG the loss in the PhNROFF was greater than that in the PhNRON component. The areas under the ROC curve (AUC) for the focal PhNRON (0.92), focal PhNROFF (0.95), and full-field PhNROFF (0.83), were not significantly different from that of the PERG N95 (0.99). CONCLUSIONS: In patients with ADOA, the PhNRON and PhNROFF components are nearly symmetrically reduced in the long-duration ERG, suggesting that ON- and OFF-RGC pathways may be equally affected.