Biomedical subjects

A O Oduntan

Publications and source records attributed to A O Oduntan.

8 recordsLinked to original sources

PubMed1999

An Arabic letter distance visual acuity test chart for young children and illiterate adults.

This paper describes the design of a kinetic response Arabic letter distance visual acuity test chart for young children and illiterate adults. An Arabic letter ein which has previously been used in the design of Arabic alphabet VA charts was employed. Four different orientations of the letter were constructed on a 5 x 5 unit format and graded according to log MAR principle of acuity scaling using an Apple computer. Inter-letter space in each row was made equal to the width of each letter in the row, and inter-row space was made equal to the height of letters in the next lower row. The chart has 14 acuity rows ranging from 4/40 to 4/2 (6/60 to 6/3) (20/200 to 20/10) (log MAR 1.0 to -0.3) at 4 metres. To establish the validity of the chart, acuity values obtained using the chart were compared with those from an existing Arabic log MAR distance VA chart and the Bailey and Lovie distance VA chart. Test retest reliability of the chart was also examined statistically. Results show that VA values from the new chart were significantly similar with those from which it was compared, and that values from the chart are reliable. The chart will be useful for evaluating vision, especially for young children and illiterate adults.

Adolescent↗

PubMed1997

Design of an Arabic near visual acuity chart.

This paper describes the design of an Arabic test chart for measurement of visual acuity at near. The chart was designed employing specially selected Arabic letters and was based on the logMAR principle devised by Bailey and Lovie. Ten Arabic letters of nearly equal legibility values (0.92-1.05) (mean = 1.00), (SD = 0.05) were used in the design of the chart. Each row of the chart has 5 letters and row legibility values range from 4.82 to 5.03 with a mean of 4.92 (SD = 0.06). The logMAR method of visual acuity scaling was used, hence the sizes of letters in the rows progress in a uniform step of 0.1 log unit. The inter-letter spacing is equal to the width of each letter in the row, while inter-row spacing is equal to the height of letter in the subjacent row. The height of letters ranged from 3.67 to 0.46 mm corresponding to visual acuity of 2.4 M to 0.3 M which is equivalent to reduced Snellen 6/36 to 6/4.5 at 0.4 m. The chart is designed for use at 40 cm with a recommended luminance level of 160 cd/m2.

Arab World↗

PubMed1996

A new Arabic distance visual acuity chart.

BACKGROUND: A new Arabic visual acuity chart has been designed using the various recommendations made by vision scientists for achieving a standardized acuity chart. Our goal was to design a standardized Arabic distance visual acuity chart. METHOD: The chart is based on the design principle devised by Bailey and Lovie. Twelve Arabic letters of nearly equal legibility values, which could be constructed on a 5 by 5 Snellen framework, were used. The LogMAR method of scaling visual acuity was used, hence the size of letters in the rows progresses in a uniform step of 0.1 logarithm unit. RESULT: The size of letters in the chart ranged from 58.2 to 4.6 mm, corresponding to visual acuity of 4/40 to 4/3 (6/60 to 6/4) (20/200 to 20/15). The chart is designed for use at 4 m; acuity values for a 6-m testing distance are, however, provided on the chart. CONCLUSION: The chart will be useful for examining Arabic speaking patients.

Arabs↗

PubMed1996

Arabic near test chart for partially sighted patients.

This paper describes the design of an Arabic alphabet near acuity chart for examination of partially sighted patients. The alphabets used have similar legibility values (0.92 to 1.05) (Mean = 1.00) (SD = 0.05) and each row of the chart has similar legibility values as the others. The LogMAR method of acuity scaling was used, therefore each row is larger in size than the preceding row by a constant value of 1.26 (0.1 log unit). The inter-letter space in a row is equal to the breadth of each letter in the row and the inter-row spacing is equal the height of letters in the subjacent row. The chart has 10 rows and visual acuity values range from 9.6 to 1.2 M (LogMAR 1.4 to 0.5) at 40 cm, corresponding to Snellen 6/144 to 6/18, 20/480 to 20/60. The chart will be useful for examining Arabic-speaking partially sighted subjects.

Arabs↗

PubMed1994

Arabic visual acuity chart for low vision examination.

An Arabic visual acuity chart has been designed for low vision examination, using ten Arabic letters constructed on a 5 x 5 framework. The chart contains seven pages with acuity values ranging from 20/600 to 20/80, corresponding to letter sizes of 26.5-3.5 cm. Interletter spaces were made one-fifth the size of each letter in a row while inter-row spaces were made equal to the height of the letters in the row below. The chart will be useful to eye care practitioners who may wish to use Arabic charts in low vision evaluation.

Adult↗

PubMed1992

The inferior conjunctiva of the monkey.

Light- and electron-microscopical techniques were used to study the structure of the inferior conjunctiva of monkeys including the third eyelid (nictitating membrane). The cell layers of the conjunctival epithelium were 8-10 at the margin, 6-8 near the limbus and 2-4 in other areas except in the third eyelid where there were 1-4 layers. The epithelium was 90-100 microns thick at the margin and 35-40 microns at the other areas except at the third eyelid where it was 10-45 microns thick; near the limbus it was 55-60 microns thick. The morphological differences between the epithelia of the various areas of the inferior conjunctiva are highlighted. The similarities and differences between the human and monkey inferior conjunctivas are discussed.

Animals↗

PubMed1992

Organization of capillaries in the primate conjunctiva.

Conjunctival capillaries in the monkey were observed in histological sections to organize approximately parallel and close to the basement membrane of the epithelium, while larger vessels including the lymphatics were disposed deeper in the stroma. This peculiar vascular organization was evident in the palpebral but not in the bulbar conjunctiva. The trilaminar relationship that existed between the conjunctival epithelium, the elastic lamina previously described [1] and the capillaries is discussed. It was argued that such subepithelial capillary organization enhances the exchange of nutrients and gases between the cornea and the conjunctival vessels across the palpebral conjunctival epithelium when the lids are shut during sleep.

Animals↗

PubMed1989

A subepithelial elastic lamina in the palpebral conjunctiva of monkeys.

Eyelids from ten cynomolgus monkeys were sectioned in a variety of orientations and the conjunctival layer examined by light and electron microscopy. An elastic lamina composed of a mesh of mature elastic fibres was present in the palpebral conjunctival stroma adjacent to the epithelium covering the area of the tarsal plate and extending to the lid margin. Mesh fibres orientated at or close to right angles to the lid margin were thicker and denser than the transverse and oblique fibres linking them. The elastic lamina was most substantial in the marginal conjunctiva bridging the interval between the tarsal plate and the mucocutaneous junction where it terminated abruptly. In this position the area occupied by the elastic mesh exceeded that of the mesh spaces. Dense collagen bundles enclosed the lamina, infiltrating the mesh spaces and attaching the lamina firmly to the tarsal plate. In the marginal zone thick elastic fibres branched forward from the lamina in a brush-like fashion penetrating the relatively soft marginal eyelid tissue obliquely between tarsal gland ducts, while other finer, more numerous fibrils passed backwards attaching the lamina to the basement membrane of the epithelium. The organisation of the elastic lamina suggests that the tension generated would act to pull the lid margins towards the surface of the eye. Production of a regular thin tear film during lid retraction following a blink is facilitated by this action.

Animals↗