October - LRS Institute of Tuberculosis & Respiratory Diseases

VISUAL PATTERN IN ETHAMBUTOL TREATED TUBERCULAR PATIENTS
B.B. LAL* and R.L. GUPTA**
Summary : Study of visual pattern in ethambutol treated tubercular patients based on observations
made in 680 cases reveals definite change of visual pattern in the form of diminution of vision and
change in normal relative extent for green colour field of vision in 81 patients of whom only 24 complained
of some visual disturbance.
Ethambutol, though previously used as a
second line drug, is now one of the standard
anti-tubercular drugs. The drug, however, has
a definite toxic effect on the eyes as reported
in literature (Corpe & Blalock 1965, Citron
1969). Since only a few patients complain of
visual disturbances during the course of ethambutol
therapy, the present study was undertaken
to find out the exact magnitude of the problem,
assuming that some patients may have some
visual disturbance but may not complain of
it. The study was conducted at Nehru Hospital
of B.R.D. Medical College, Gorakhpur (U.P.)
from 1976 to 1980.
Material & Method
In all, 680 patients were included in this
study; out of them 471 were males and 209
were females, majority being in 20-30 years age
group (Table 1).
Age group
Below 20 years
20+ to 30 years
30+to40years
40+and above
All ages
TABLE I
Age ant! Sex Distribution
Male
471
Female
19
113
52
25
209
Total
52
394
161
73
680
All patients were subjected to general ocular
examinations with special reference to vision
before starting the treatment and thereafter
at monthly intervals or even earlier in cases
who developed any ocular symptom. Besides
the general, the routine ocular examinations
consisted of the following:-
1. Acuity of vision
(a) for distant vision by Snellen’s chart
(b) for near vision by Jaeger’s test types
2. Colour vision
by Ishihara’s Isochromatic charts
3. Field of vision
(a) Central field of vision by Campimetery
(b) Peripheral field of vision with white,
blue, red and green targets of isopter
5/330
4. Fundus Examination by
(a) Indirect Ophthalmoscopy
(b) Direct Ophthalmoscopy
Observations
Only 24 patients complained of ocular symptoms.
Blurring of vision was the commonest symptom
(66.6%). The other symptoms were diminution
of vision and headache (Table 2). The
TABLE 2
Visual Symptomatology
Symptom
No. of Patients %
All the patients were on ethambutol along
with other drugs. The dose of ethambutol was
25mg/kg body weight per day for sixty days
followed by 15mg/kg body weight per day till
completion of 18 months from the start of
therapy.
Blurring of vision
Diminution of vision
Headache
16
5
3
66.6
20.8
12.5
*Lecturer in Ophthalmology
**Lecturer in Tuberculosis & Chest Diseases
From Departments of Tuberculosis and Ophthalmology, B.R.D. Medical College, Gorakhpur.
Ind. J. Tub., Vol. XXIX, No. 4