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.

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.

Normative Data for Parameters of Accommodation in African Schoolchildren.

SIGNIFICANCE: The reported interracial differences in normative data for parameters of accommodation call for investigating population-specific normative values. The study investigated and presents expected data for accommodative parameters among Ghanaian children. PURPOSE: This study aimed to determine expected values for parameters of accommodation among schoolchildren in the Central Region of Ghana. METHODS: This prospective cross-sectional study used a multistage cluster sampling approach. Normal participants were asymptomatic (Convergence Insufficiency Symptom Survey score ˂16), with unaided visual acuity or best-corrected visual acuity of 0.0 or better logMAR for each eye and having no ocular disease or no manifest strabismus. Normal participants underwent push-up and minus-lens-to-blur amplitude of accommodation tests, accuracy of accommodative response (using the monocular estimation method), and monocular and binocular accommodative facility testing. RESULTS: A total of 1261 normal participants within ages 11 to 17 years (mean, 14.75 ± 1.53 years) met the inclusion criteria. The mean normative data for the population include push-up amplitude of accommodation (14.04 ± 2.95 D), minus-lens-to-blur amplitude of accommodation (12.33 ± 2.55 D), and accuracy of accommodative response using the monocular estimation method (0.62 ± 0.22 D), monocular accommodative facility (9.80 ± 3.20 cycles per minute), and binocular accommodative facility (9.40 ± 3.30 cycles per minute). Age-predicted linear regression equations for the amplitude of accommodation are push-up amplitude of accommodation (16.74 - 0.18 × age in years) and minus-lens-to-blur amplitude of accommodation (15.7 - 0.23 × age in years). CONCLUSIONS: The study provides normative data for accommodative parameters that clinicians may use with Ghanaian populations of similar ages.

Normative Data for Nonstrabismic Binocular Vision Parameters in African Schoolchildren.

SIGNIFICANCE: With reported population differences in parameters of nonstrabismic binocular vision, the present study investigated and reports normative data among a sample of African children. PURPOSE: This study aimed to determine expected binocular visual function data among schoolchildren in the Central Region of Ghana. METHODS: The study used a prospective cross-sectional design and used a multistage cluster sampling approach. Eligible normal participants selected through the administration of Convergence Insufficiency Symptom Survey questionnaire (score <16) and preliminary vision screening underwent comprehensive binocular vision testing. Only data for participants who expressed no difficulty with the specific procedures were analyzed. RESULTS: A total of 1261 normal participants (11 to 17 years [mean, 14.75 ± 1.530 years]) were selected for comprehensive binocular vision testing in the normative data study. The means with ±1 standard deviation for normative data for the nonstrabismic binocular vision parameters include the following: accommodative target near point of convergence (NPC) break (6.10 ± 1.67 cm), NPC recovery (8.17 ± 1.67 cm), fixation light with red-green anaglyph (RG NPC) break (8.51 ± 2.43 cm), RG NPC recovery (10.95 ± 2.60 cm), cover test distance phoria (0.12 ± 0.79 exophoria), cover test near phoria (2.1 ± 2.3 exophoria), modified Thorington test near phoria (1.9 ± 2.5 exophoria), negative relative accommodation (+2.54 ± 0.75 D), positive relative accommodation (-2.58 ± 0.81 D), and the accommodative convergence over accommodation ratio (2.80 ± 1.07:1). Age (in years)-predicted normal linear regression equations for NPC break (5.13 + 0.07 × age), RG NPC break (10.00 - 0.10 × age), RG NPC recovery (12.83 - 0.13 × age), positive relative accommodation (2.05 + 0.04 × age), and the gradient accommodative convergence over accommodation ratio (3.97 - 0.08 × age) serve as a guide. CONCLUSIONS: The study provides expected data that optometrists may use with similar aged Black African populations.

Socio-demographic factors modify awareness, knowledge, and perceived risk of glaucoma in rural and urban residents in Ghana: a population-based survey.

PURPOSE: To evaluate the awareness, knowledge and the perception of risks of glaucoma among rural and urban dwellers in Ghana, a high prevalent country, in order to provide information for health promotion planning. METHOD: In a population-based descriptive cross-sectional survey, 1200 adults were selected from household settings, using a two-stage cluster and simple systematic random sampling. Quantitative data collection, using interviewer-administered questionnaire, was employed. Descriptive statistics were performed using chi-square, ordinal univariate, multinomial and multivariate logistic regression models used to calculate odds ratio with 95% confidence interval (CI) to identify predictive factors. RESULTS: Overall, only 326 (27.2%, 95% CI = 24.6-29.7) indicated they were aware of glaucoma, whereas 331 (27.6%, 95% CI = 24.6-29.7) had ever undergone an eye screening. Low knowledge was demonstrated in 152 (46.6%, 95% CI = 41.2-52.0) and high knowledge in 99 (30.4%, 95% CI = 25.4-35.4) glaucoma-aware participants. Only 238 (19.8%, 95% CI = 17.6-22.1) of respondents presumed themselves to be at risk of developing glaucoma. Having eye examination (within the last 6 months) was positively associated with knowledge (adjusted odds ratio (AOR) = 1.413; 95% CI = 0.9-1.896) and awareness (AOR = 1.13; 95% CI = 0.938-2.449). Three levels of education (no education (AOR = 0.041; 95% CI = 0.016-0.11), primary (AOR = 0.057; 95% CI = 0.018-0.179), and middle school (AOR = 0.254; 95% CI = 0.127-0.51)) were associated with low knowledge while all levels of education were inversely associated with awareness. Perceived risk of glaucoma was also influenced by area of residence (rural (AOR = 0.344; 95% CI = 0.21-0.57)), being young (18-24 years (AOR = 4.308; 95% CI = 2.36-7.88)) and having previously undergone screening for glaucoma (AOR = 13.200; 95% CI = 5.318-32.764). CONCLUSION: The main modifiers of glaucoma awareness and knowledge were education and previous eye examination, but awareness had additional factor of area of residence. Perceived risk of glaucoma was influenced by being young and living in urban areas.

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.

Ocular Health and Safety Assessment among Mechanics of the Cape Coast Metropolis, Ghana.

PURPOSE: To conduct an ocular health and safety assessment among mechanics in the Cape Coast Metropolis, Ghana. METHODS: This descriptive cross sectional study included 500 mechanics using multistage sampling. All participants filled a structured questionnaire on demographic data, occupational history and ocular health history. Study participants underwent determination of visual acuity (VA) using LogMAR chart, external eye examination with a handheld slit lamp biomicroscope, dilated fundus examination, applanation tonometry and refraction. RESULTS: Out of 500 mechanics, 433 were examined (response rate, 87%) comprised of 408 (94.2%) male and 25 (5.8%) female subjects. The prevalence of visual impairment (i.e. presenting VA < 6/18) among the respondents was 2.1%. Eye injuries were reported in 171 (39.5%) mechanics probably due to the large number of workers, 314 (72.5%), who did not use eye protective devices. Mechanics in the auto welding category were at the highest risk of sustaining an eye injury (odds ratio [OR], 13.4; P < 0.001). Anterior segment ocular disorders were mostly pterygia while posterior segment eye disorders included glaucoma suspects and retinochoroidal lesions. The development of pterygia was associated with the number of years a mechanic stayed on the job. Eye care seeking behavior among the participants was poor. CONCLUSION: Eye injuries were prevalent among the mechanics as the use of eye protection was low. Eye safety should be made an integral part of the public health agenda in the Cape Coast Metropolis.

Visual function among commercial vehicle drivers in the central region of Ghana / Estudio de la función visual de los conductores de vehículos comerciales en la región central de Ghana

Aim: To determine the relationship between some visual functions: colour vision defects, abnormal stereopsis, visual acuity and the occurrence of road traffic accident (RTAs) among commercial vehicle drivers in the central region of Ghana, and to assess their knowledge of these anomalies. Method: A descriptive cross-sectional study employing a multi-stage random sampling approach was conducted in the major commercial towns within the central region of Ghana. Participants were taken through a comprehensive eye examination after the administration of a structured questionnaire. Results: 520 male commercial vehicle drivers were enrolled for this study with a mean age of 39.23years ±10.96 years and mean visual acuity of 0.02±0.08 logMAR. Protans were more likely to be involved in RTAs (χ2=6.194, p=0.034). However, there was no statistically significant association between abnormal stereopsis (OR=0.89 95% CI: 0.44-1.80, p=0.56), poor vision due to refractive error (χ2=3.090, p=0.388) and the occurrence of RTAs. While 86.9% were aware of abnormal stereopsis, only 45% were aware of colour vision defects. There was a statistically significant association between stereopsis anomaly and colour vision defect (r=0.371, p<0.005). Conclusion: The study found an association between protanopia and RTAs but none between stereopsis anomalies, refractive errors and the occurrence of RTAs. Drivers were less knowledgeable on colour vision defects as compared to stereopsis anomalies (AU)

Objetivo: Determinación de la relación entre algunas funciones visuales -alteraciones de la visión cromática, alteraciones de la estereopsis y agudeza visual- y la ocurrencia de accidentes de tráfico entre los conductores de vehículos comerciales en la región central de Ghana, así como evaluación de su conocimiento sobre estas anomalías. Método: Se realizó un estudio descriptivo cruzado, utilizando una muestra aleatoria de múltiples fases, en las principales ciudades comerciales de la región central de Ghana. A los participantes se les realizó un amplio examen visual tras la entrega de un cuestionario estructurado. Resultados: Se incluyó en este estudio a 520 varones conductores de vehículos comerciales, con una edad media de 39,23 años ±10,96 años, y una agudeza visual de 0,02±0,08 logMAR. Los sujetos con protanopia tuvieron más probabilidad de sufrir un accidente de tráfico (χ2=6,194, p= 0,034). Sin embargo, no se produjo una asociación estadísticamente significativa entre las alteraciones de la estereopsis (OR=0,89 95% IC: 0,44-1,80, p = 0,56), la baja visión debida a error refractivo (χ2=3,090, p=0,388), y la ocurrencia de accidentes de tráfico. Aunque el 86,9% eran conscientes de las alteraciones de la estereopsis, sólo el 45% estaba al corriente de las alteraciones de la visión cromática. Se produjo una asociación estadísticamente significativa entre las alteraciones de la estereopsis y las alteraciones de la visión cromática (r = 0,371, p < 0,005). Conclusión: El estudio halló una asociación entre la protanopia y los accidentes de tráfico, y ninguna asociación entre las alteraciones de la estereopsis, los errores refractivos y la ocurrencia de accidentes de tráfico. Los conductores eran menos conscientes de las alteraciones de la visión cromática que de las alteraciones de la estereopsis (AU)

Visual impairment attributable to uncorrected refractive error and other causes in the Ghanaian youth: The University of Cape Coast Survey / Deficiencia visual atribuible a error refractivo no corregido y a otras causas en los jóvenes de Ghana: Estudio de la Universidad de Cape Coast

Purpose: To determine the prevalence of visual impairment attributable to refractive error and other causes in a youthful Ghanaian population. Methods: A prospective survey of all consecutive visits by first-year tertiary students to the Optometry clinic between August, 2013 and April, 2014. Of the 4378 first-year students aged 16-39 years enumerated, 3437 (78.5%) underwent the eye examination. The examination protocol included presenting visual acuity (PVA), ocular motility, and slit-lamp examination of the external eye, anterior segment and media, and non-dilated fundus examination. Pinhole acuity and fundus examination were performed when the PVA≤6/12 in one or both eyes to determine the principal cause of the vision loss. Results: The mean age of participants was 21.86 years (95% CI: 21.72-21.99). The prevalence of bilateral visual impairment (BVI; PVA in the better eye ≤6/12) and unilateral visual impairment UVI; PVA in the worse eye ≤6/12) were 3.08% (95% CI: 2.56-3.72) and 0.79% (95% CI: 0.54-1.14), respectively. Among 106 participants with BVI, refractive error (96.2%) and corneal opacity (3.8%) were the causes. Of the 27 participants with UVI, refractive error (44.4%), maculopathy (18.5%) and retinal disease (14.8%) were the major causes. There was unequal distribution of BVI in the different age groups, with those above 20 years having a lesser burden. Conclusion: Eye screening and provision of affordable spectacle correction to the youth could be timely to eliminate visual impairment (AU)

Objetivo: Determinar la prevalencia de la deficiencia visual atribuible al error refractivo y a otras causas en una población de jóvenes de Ghana. Métodos: Estudio prospectivo de todas las visitas consecutivas realizadas por estudiantes terciarios de primer año que acudieron a la Clínica de Optometría entre Agosto de 2013 y Abril de 2014. De los 4.378 estudiantes de primer año registrados, de edades comprendidas entre 16 y 39 años, 3.437 (78,5%) se sometieron a un examen ocular. El protocolo del examen incluyó la revisión de la agudeza visual (AV), la motilidad ocular y la biomicroscopía del ojo externo, segmento anterior y medio, y el examen del fondo de ojo sin dilatación. Los exámenes de la agudeza con agujero estenopeico y del fondo de ojo se realizaron en aquellos casos de AV ≤ 6/12 en uno o ambos ojos para determinar la causa principal de la pérdida de visión. Resultados: La edad media de los participantes fue de 21,86 años (95% IC: de 21,72 a 21,99). La prevalencia de la deficiencia visual bilateral (BVI; AV en el mejor ojo ≤ 6/12) y la deficiencia visual unilateral (UVI; AV en el peor ojo ≤ 6/12) fue del 3,08% (95% IC: de 2,56 a 3,72) y el 0,79% (95% IC: de 0,54 a 1,14), respectivamente. En 106 participantes con BVI, las causas principales fueron el error refractivo (96,2%) y la opacidad corneal (3,8%). De los 27 participantes con UVI, el error refractivo (44,4%), la maculopatía (18,5%) y la enfermedad retiniana (14.8%) fueron los principales motivos. Se produjo una distribución desigual de la BVI en los diferentes grupos de edad, habiendo un menor impacto en aquellos participantes con edades superiores a 20 años. Conclusión: La exploración ocular y la adaptación de una corrección en gafa asequible en los jóvenes podría eliminar a tiempo la deficiencia visual (AU)

Visual function among commercial vehicle drivers in the central region of Ghana.

AIM: To determine the relationship between some visual functions: colour vision defects, abnormal stereopsis, visual acuity and the occurrence of road traffic accident (RTAs) among commercial vehicle drivers in the central region of Ghana, and to assess their knowledge of these anomalies. METHOD: A descriptive cross-sectional study employing a multi-stage random sampling approach was conducted in the major commercial towns within the central region of Ghana. Participants were taken through a comprehensive eye examination after the administration of a structured questionnaire. RESULTS: 520 male commercial vehicle drivers were enrolled for this study with a mean age of 39.23 years ±10.96 years and mean visual acuity of 0.02±0.08 logMAR. Protans were more likely to be involved in RTAs (χ(2)=6.194, p=0.034). However, there was no statistically significant association between abnormal stereopsis (OR=0.89 95% CI: 0.44-1.80, p=0.56), poor vision due to refractive error (χ(2)=3.090, p=0.388) and the occurrence of RTAs. While 86.9% were aware of abnormal stereopsis, only 45% were aware of colour vision defects. There was a statistically significant association between stereopsis anomaly and colour vision defect (r=0.371, p<0.005). CONCLUSION: The study found an association between protanopia and RTAs but none between stereopsis anomalies, refractive errors and the occurrence of RTAs. Drivers were less knowledgeable on colour vision defects as compared to stereopsis anomalies.

Visual impairment attributable to uncorrected refractive error and other causes in the Ghanaian youth: The University of Cape Coast Survey.

PURPOSE: To determine the prevalence of visual impairment attributable to refractive error and other causes in a youthful Ghanaian population. METHODS: A prospective survey of all consecutive visits by first-year tertiary students to the Optometry clinic between August, 2013 and April, 2014. Of the 4378 first-year students aged 16-39 years enumerated, 3437 (78.5%) underwent the eye examination. The examination protocol included presenting visual acuity (PVA), ocular motility, and slit-lamp examination of the external eye, anterior segment and media, and non-dilated fundus examination. Pinhole acuity and fundus examination were performed when the PVA≤6/12 in one or both eyes to determine the principal cause of the vision loss. RESULTS: The mean age of participants was 21.86 years (95% CI: 21.72-21.99). The prevalence of bilateral visual impairment (BVI; PVA in the better eye ≤6/12) and unilateral visual impairment UVI; PVA in the worse eye ≤6/12) were 3.08% (95% CI: 2.56-3.72) and 0.79% (95% CI: 0.54-1.14), respectively. Among 106 participants with BVI, refractive error (96.2%) and corneal opacity (3.8%) were the causes. Of the 27 participants with UVI, refractive error (44.4%), maculopathy (18.5%) and retinal disease (14.8%) were the major causes. There was unequal distribution of BVI in the different age groups, with those above 20 years having a lesser burden. CONCLUSION: Eye screening and provision of affordable spectacle correction to the youth could be timely to eliminate visual impairment.

The efficacy of stingless bee honey for the treatment of bacteria-induced conjunctivitis in guinea pigs.

The efficacy of the conjunctival application of a crude concentration of stingless bee honey (SBH) for the treatment of bacterial conjunctivitis was investigated in an animal model. Bacterial conjunctivitis caused by Staphylococcus aureus or Pseudomonas aeruginosa was induced in Hartley guinea pigs. The conjunctival application of SBH or gentamicin was used for treatment, and the results of this treatment were compared with control values. Inflammatory signs, duration of infection (ie, positive culture), and time for the complete resolution of infection with S. aureus or P. aeruginosa were shortened by the conjunctival application of 1 drop (70 µL) of crude SBH twice daily. The potency of SBH was comparable with that of gentamicin. SBH may be a rational agent for the treatment of infective conjunctivitis in humans; it is inexpensive and commonly available to the rural population.