treatment of amblyopia

The purpose of this article is to present our experiences with red-filter treatment and to re-evaluate our earlier cases (Malik, Gupta, Choudry, and Sen, 1968; Malik, Gupta, and Choudry, I969a,b). This is a convenient and simple method, as the patient does not need to come to the clinic daily for treatment. The amblyopic eye is occluded (non-conventional occlusion) most of the time, so that the patient can continue his daily work without any handicap. The healthy eye is occluded only for short periods when the patient is using the red filter. Methods and material The cases were selected from the amblyopia and squint clinic of Irwin Hospital, New Delhi. A detailed history was elicited, and a thorough ophthalmic examination made. Fixation was de-termined by Keeler's Projectoscope with a Linksz Star graticule (Malik and others, I969a). A series of 55 patients with amblyopia and eccentric fixation was given red-filter treatment for 2 to 75 weeks (average i6.5). Their ages ranged from 5 to 42 years (average 15 4). The amblyopic eye was occluded during waking hours except when the patient was required to read with the red filter in front of the amblyopic eye and the healthy eye occluded. Each word was spelt out, so that the patient had to observe each letter with concentration. The size of the letters was progressively reduced and the treatment times gradually increased from 30 minutes to 4 hours. Visual acuity was determined by the ability to read a whole line of Snellen's Optotypes. A gain of one line and a shift of fixation towards the fovea were taken as the criteria of improvement. Of the 55 cases, fifteen were followed up for I 2 to 49 months after the cessation of treatment