Determining the Efficacy of Full-time Occlusion Therapy in Severe Amblyopia at Different Ages
Determining the Efficacy of Full-time Occlusion Therapy in Severe Amblyopia at Different Ages
Objective: To find out how much visual improvement is possible in severe amblyopia using
 full-time occlusion therapy with an eye patch and to see if improvement is influenced by the
 patient's age.

 Methods: An interventional clinical trial of 115 consecutive cases with unilateral, severe
 amblyopia was conducted at a tertiary referral center from Jan 2010 to Oct 2012. Patients
 were divided into three age groups: 3-7 years (n= 38), 8-12 years (n=41), 13-35 years (n=36).
 After a complete ophthalmological examination by a single ophthalmologist, cases with organic
 visual loss were excluded; cases with previous part-time occlusion therapy that had failed
 were included in the study. Patients were given optimal refractive correction for a month,
 followed by full-time occlusion therapy along with near visual activities for 3-4 hours/day.
 The therapy was continued until maximum visual recovery was achieved (6/6 Snellen's). Therapy
 was gradually reduced and stopped. Patients were followed-up regularly for the next 18
 months.
Amblyopia, ('blunt vision' in Ancient Greek), also known as lazy eye, is a visual deficiency
 in an eye that is otherwise physically normal, or that is greater than would be expected from
 any structural abnormalities of the eye. There are unsubstantiated beliefs that it is more
 difficult to treat amblyopia in older age groups, that children that have already received
 failed amblyopia therapy do not respond to treatment and that full-time occlusion therapy may
 result in occlusion (disuse) amblyopia of the good eye. The aim of this study was to assess
 whether these beliefs are true. Materials and methods This was a prospective, interventional
 clinical trial of 115 consecutive cases with unilateral, severe amblyopia conducted at a
 tertiary referral center in Lahore, Pakistan, from January 2010 to October 2012. Eligibility
 criteria included an age of over three years, visual acuity in the amblyopic eye from 6/60
 Snellen's or even counting fingers only, visual acuity in the sound eye of 6/6. A complete
 ophthalmic examination was performed by only one ophthalmologist (SI). This included
 examining the fixation pattern of both eyes, presence or absence of a phoria or a tropia by a
 cover-uncover test, fundus examination and color vision using Ishihara color plates. Any case
 with an organic cause for visual loss was excluded from the study after a thorough
 ophthalmological examination. Assessment of visual acuity of either eye for both near and
 distance acuity (Snellen's and ETDRS charts) refraction and Best Corrected Visual Acuity
 (BCVA) was performed by a trained optician who was masked to the study and patient's
 demographics.
Inclusion Criteria:

 -  a visual acuity of 6/60 or 0.1-0.2 ETDRS in one eye and 6/6 or 1.0 ETDRS in the good
 eye

 -  strabismic amblyopia

 -  patients of any age were included.

 Exclusion Criteria:

 -  structural damage to the eye (organic amblyopia)

 -  ametropic amblyopia