Current Issue - 2006, Volume 1 Number 2 & 3

ORIGINAL ARTICLES

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PREVALENCE OF COLOUR VISION DEFICIENCY AMONG MEDICAL STUDENTS AND HEALTH PERSONNEL

R Balasundaram1 FAFPM, FRCP, Sagili Chandrasekhara Reddy2 MS(Ophth), FRCS(Glasgow)
1President-Elect, Academy of Family Physician of Malaysia (Formerly, Professor of Family Medicine, IMU)
2Associate Professor, Department of Ophthalmology, International Medical University, Seremban.

Address for correspondence: Assoc Prof Dr SC Reddy, Department of Ophthalmology, International Medical University, Jalan Rasah, 70300 Seremban, Negeri Sembilan, Malaysia. Tel: 06-7677798, Fax: 06-7677709, Email: sagili_chandrasekharareddy@imu.edu.my

ABSTRACT

A survey of colour vision deficiency among 1427 medical students and healthcare personnel in Seremban revealed a prevalence of 3.2% with a marked male predominance (males 6.7%, females 0.4%). In view of the potential difficulties faced by such personnel in clinical works, early detection of this deficiency allowed appropriate counselling.

Keywords: Colour blindness, prevalence, health care workers

Balasundaram R, Reddy SC. Prevalence of colour vision deficiency among medical students and health personnel. Malaysian Family Physician. 2006;1(2&3):52-53

INTRODUCTION
The prevalence of deficient colour vision is reported to be 8% in White UK men and 0.5% in women.1 In a study of 1214 primary school children in Petaling Jaya, Selangor, the prevalence of colour vision deficiency was found to be 2.6% (males 4.8%, females 0.2%).2 The commonest form of deficient colour vision is red-green deficiency; total colour blindness is very rare. Colour vision defects are inherited as X-linked recessive disorder, which explain its predominance among the males. Even though no specific treatment is available for those affected by this disorder, it is helpful to detect it so that those affected can be counselled about future occupation. The importance of detecting colour vision deficiencies among health personnel is not well appreciated in Malaysia. Thus, we have conducted a study to document the prevalence of this problem among the health personnel and medical students.

METHODS
Medical students from International Medical University, and healthcare personnel from Hospital Seremban were invited to participate in a study to determine the prevalence of colour vision deficiency. The colour vision deficiency was determined using the 24-plate Ishihara’s Test of Colour Vision.3 The colour vision testing plates are held at 75 cm from the person and tilted at right angle to the line of vision. The test was done in a properly lighted room resembling to the effect of natural day light. The person was asked to read the numbers seen on the test plates 1 to 17, and the time given for telling the number was less than 5 seconds. An assessment of the reading of plates 1 to 15 determines the normality or defectiveness of colour vision. If 13 or more plates are read correctly, the colour vision is regarded as normal. If only 9 or less than 9 plates are read correctly, the colour vision was regarded as red green deficient. The plates 16 and 17 are used to differentiate protan and deutan types of colour vision efficiency. An informed consent was taken from all persons. Ethical approval for this study was obtained from the Ethics Committee of International Medical University.

RESULTS
A total of 1427 persons (658 medical students from International Medical University and 769 health care personnel from Hospital Seremban) participated in this study. The gender and ethnic distribution of the study subjects is shown in Table 1.

Table 1: Sex-specific prevalence of deficient colour vision by ethnicity and category of personnel

Colour blindness

Males Normal vision

Red green deficiency

Females Normal vision

Red green deficiency

Ethnic group
Malay
Chinese
Indian


275 (91.7)
243 (95.3)
63 (92.6)


25 (8.3)
12 (4.7)
5 (7.4)


386 (99.5)
300 (99.7)
115 (100)


2 (0.5)
1 (0.3)
0

Category
Medical students
Doctors
Medical assistants*
Nurses*
Others**


275 (94.8)
33 (97.1)
259 (91.8)
NA
14 (82.4)


15 (5.2)
1 (2.9)
23 (8.2)
NA
3 (17.6)


367 (99.7)
50 (100)
NA
356 (99.7)
28 (96.6)


1 (0.3)
0
NA
1 (0.3)
1 (3.4)

NA= not applicable
* including trainees    
**attendant, dental assistant, dentist, dietician, physiotherapist, pharmacist, pharmacy assistant, laboratory technician

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