Normative values for clinical measures used to classify accommodative and vergence anomalies in a sample of high school children in South Africa / Valores normativos para mediciones clínicas para la clasificación de las anomalías de acomodación y vergencia en una muestra de estudiantes de secundaria sudafricanos

Aim: To determine normative values for stereoacuity, accommodative and vergence measures for high school populations. Methods: Using a multi-stage random cluster sampling, 1211 children (481 males and 730 females) between 13 and 18 years of age, with a median age of 16 years, were selected. Visual acuity, stereoacuity and suppression, refractive errors, near point of convergence, heterophoria and fusional vergences, as well as, amplitude of accommodation, accommodative response, facility and relative accommodation were evaluated. Results: Most data did not have a normal distribution. The range of normality for the vergence measures were: near point of convergence break, 5-10 cm, recovery, 6-13 cm, near lateral phoria, 2.5-6 prism dioptre (pd) (nasal), near vertical, orthophoria to 0.50 pd, negative fusional vergence break, 12-23pd, recovery, 8-17 pd, positive fusional vergence break, 16-35 and recovery 11-24 pd. For accommodative measures, the range of normality for accommodative measures was: amplitude of accommodation, 12-18 pd, accommodative response, plano to + 0.75 D, binocular accommodative facility, 5-12 cycles per minute (cpm), negative relative accommodation, 1.75-2.50 DS, positive relative accommodation, -2.0 to -3.0 DS and 17-69 s arc for stereoacuity. Conclusion: This study provides norms for clinical measures which could be used to classify accommodative and vergence parameters for children aged 13-18 years in this population or beyond. Findings should be applied in the context of the measurement techniques and the associated limitations outlined in this report

Objetivo: Determinar los valores normativos para la estereoagudeza, y las mediciones de acomodación y vergencia para poblaciones de estudiantes de secundaria. Métodos: Utilizando un muestreo de grupo aleatorio de etapas múltiples, se seleccionaron 1.211 chicos (481 varones y 730 mujeres) de edades comprendidas entre 13 y 18 años, con una edad media de 16 años. Se evaluaron la agudeza visual, estereoagudeza y supresión, errores refractivos, punto próximo de convergencia, heteroforia y vergencias fusionales, así como amplitud de acomodación, respuesta acomodativa, flexibilidad de acomodación y acomodación relativa. Resultados: Muchos datos no reflejaron una distribución normal. El rango de normalidad para las mediciones de vergencia fue: punto próximo de rotura de convergencia, de 5 a 10 cm, recobro, de 6 a 13 cm, foria lateral de cerca, de 2,5 a 6 dioptrías prismáticas (pd) (nasal), vertical de cerca, ortoforia 0,5 pd, rotura de vergencia fusional negativa, 12-23 pd, recobro, 8-17 pd, rotura de vergencia fusional positiva, 16-35 y recobro 11-24 pd. Para las mediciones de la acomodación, el rango de normalidad para mediciones acomodativas fue: amplitud de acomodación, de 12 a 18 pd, respuesta acomodativa, de plano a + 0,75 D, flexibilidad acomodativa binocular, de 5 a 12 ciclos por minuto (cpm), acomodación relativa negativa, de 1,75 a 2,5 DS, acomodación relativa positiva, de -2 a -3 DS y 17-69 s arc para estereoagudeza. Conclusión: Este estudio aporta normas para mediciones clínicas que podrían utilizarse para clasificar los parámetros de acomodación y vergencia medidos en niños de edades comprendidas entre 13 y 18 años en esta población, o con edades superiores. Deberán aplicarse los hallazgos en el contexto de las técnicas de medición y las limitaciones asociadas destacadas en este estudio

An anatomical investigation of the coronary ostia and its relationship to the sinotubular junction within a select South African population

The coronary ostia (CO) lie within the left and right aortic sinuses, respectively; and are bound by the sinotubular junction (STJ) superiorly. The high frequency of cardiac procedures that require catheterization has necessitated the reappraisal of the anatomy of the origin of the coronary arteries. Therefore, this study aimed to describe the CO by recording its diameter, shape, and relation to the sinotubular junction in a select South African population.The present study included the gross dissection of 50 formalin fixed, adult cadaveric hearts. The average diameter of the right coronary ostium (RCO) was 3.29mm and the left coronary ostium (LCO) was 3.87mm. With regard to the shape of the ostia, the RCO was described as circular in 52% (26/50), horizontally ellipsoid in 24% (12/50) and vertically ellipsoid in 24% (12/50) of cases. The LCO was circular in 30% (15/50), horizontally ellipsoid in 60% (30/50) and vertically ellipsoid in 10% (5/50) of cases. The RCO was located below the STJ in 88% (44/50) and at the level of the STJ in 12% (6/50) of cases. The LCO was recorded below the STJ in 64% (32/50), at the level of the STJ in 32% (16/50) and above the STJ in 4% (2/50) of cases. Multiple ostia arising from a single aortic sinus was recorded in 14% (7/50) of cases. In 2% (1/50) of cases, the RCO was located in the non-coronary sinus. In addition, the RCO arose from the left aortic sinus in 2% of cases. The results of the present study correlate with those of previous studies. Anomalous CO, although asymptomatic has been linked to myocardial infarction and sudden cardiac death. It is, therefore, imperative for the clinician to be aware of variant CO anatomy, which may alert them to the predisposition of cardiac risks

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Development of the paranasal air sinuses in a South African Population utilising three dimensional (3D) reconstructed models

The anatomy of the paranasal air sinuses (PAS) may vary in form and size across populations, and between the sexes and age (Yun et al., 2011). This study aimed to estimate the volumes of the PAS within a South African population using the latest available radiological techniques. Computerized tomography scans (n=480) were reviewed from the Pietermaritzburg and Durban public and private sector hospitals (KwaZulu-Natal, South Africa). The sample consisted of 276 males, 204 females, with age range 1-25 yrs, representing the two main population groups (black African and white). The age range was divided into eight, three-year cohorts viz. 1-3; 4-6; 7-9; 10-12; 13-15; 16-18; 19-21; 22-25. These scans were processed by axial manual segmentation of the air sinuses using a 3D Slicer Program (http://www.slicer.org) to construct a three dimensional (3D) volume model of each PAS bilaterally, with 3840 3D models developed. Maximum (max.) to minimum (min.) volumes for each PAS was as follows for ages: maxillary [max: 31563.3 mm3(R), 32062.3 mm3(L); min: 49.4 mm3(R), 25.4 mm3(L)], frontal [max: 22908.6 mm3(R), 21289.0 mm3(L); min: 50.6 mm3(R), 30.2 mm3(L)], sphenoid [max: 15844.6 mm3 (R), 15433.7 mm3(L); min: 6.3 mm3(R), 7.3 mm3(L)] and ethmoid [max: 14327.5 mm3(R), 13162.0 mm3(L); min: 18.9 mm3(R), 12.6 mm3(L)]. This demonstrated that the maxillary was the largest and the ethmoid the smallest PAS at full growth. At 1-3 years of age, the maxillary air sinus was the largest and the sphenoid air sinus was the smallest. Growth of the air sinuses correlated positively with age. Mean volumes appear to be larger on the left side at full growth, although not statistically significant. Sexual dimorphism was statistically significant for the right frontal sinus. Regarding population groups, notable volume differences were observed in the maxillary sinus bilaterally and left sphenoid sinuses unilaterally. There appeared to be four distinct periods in which the growth of the PAS changed. From ages 1 to 7 years there was a gradual increase with a peak increase from 7 to 9 years, continually increasing in growth rapidly, reaching a maximum by 16 to 18 years of age followed by a plateau thereafter. This study presented data of the PAS of the South African populations using 3D reconstructed models. It is apparent that a study consisting of a large sample of 3D models of the PAS has not been fully reported. In particular, the volume of the ethmoid air sinus from 1 to 25 years of age was documented, which was not fully described. The study confirmed differences in terms of the paranasal air sinuses’ size across populations, particularly the maxillary and sphenoid air sinuses, and sex differences viz. the right frontal air sinus

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