Ocular Morbidity Among Methadone users in Kathmandu Valley

Author Shrestha C****, Manoranjan A**, Shrestha SM***, Shrestha S*,

Abstract


INTRODUCTION: Methadone is used as an oral substitution therapy to intravenous drug users to minimize
the side effects of the intravenous drug use. This study is conducted to find out ocular morbidity among
methadone users in Kathmandu valley.

METHOD: Clients on methadone maintenance therapy at a rehabilitation centre Kathmandu were included in
the study.A cross sectional study was conducted with a sample size of 68 in the year 2013.Ocular examination
included visual acuity testing, extraocular movements, cover test, colour vision, stereoacuity, horizontal prism
fusion range, accommodation and schirmer’s test. Anterior segment and posterior segment were evaluated.

RESULT: Among 68 participants, 17.6% were hepatitis C positive, 10.3% were HIV positive and 5.9% had
history of pulmonary tuberculosis. Age ranged from 20 to 59 years with 66.17% in the age group 21-30 years.
91.17% participants were males. Regarding the duration of methadone use, 48.52% were on methadone for
less than 1 year, 8.82% for 1 year, 16.17% for 2 years, 10.29% for 3 years 4.41% for 4 years, 8.82% for 5 years
and 4.41% for more than 5 years.20.58% were on <10mg of methadone, 30.88%were on 11-20mg, 20.58%
were on 21-30mg, 10.29% were on 31-40mg and 17.64% were on >40mg of methadone.
Regarding color vision, red green color defect was seen in 35.29%. Dry eye was seen in 51.47%. Regarding
accommodation, 52.2% had 11-20 cm and 10.3% had >21 cm of accommodation while 37.3% had normal
accommodation (6-10 cm). Horizontal fusion range was 10-20 prism dioptres in 39.70%, 21-30 prism dioptres
in 14.70% and 31-40 prism dioptres in 44.11% while it was absent in 2.94% with manifest strabismus.
Regarding the threshold of stereoacuity, 88.23% had ≤ 60 seconds of arc and 11.76% had >60 seconds of arc
of stereoacuity. However, convergence has been found to be within normal limits among 78% methadone
users. Refractive error was present in 47.05%, 1.4% had episcleritis, 1.4% had conjunctivitis and 1.4% had
dragged disc. Statistically significant association has been observed between the dose of methadone and
accommodation.

CONCLUSION: Ocular morbidities like colour vision defect, dry eye, poor accommodation, reduced
stereoacuity and poor horizontal fusion range was found among methadone users in Kathmandu valley.

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