[Results of late onset amblyopia therapy for excentric fixation in different forms of amblyopia]

The objective of this study was to describe the therapeutic prognoses for excentric fixation in relation to the underlying diagnoses.

We investigated the clinical development of therapy for permanent occlusion (90%) or standard occlusion (10%) in 32 children up to a maximum age of 7 years with the following: strabismus convergens: n = 12, microstrabismus: n = 10, secondary sensory esotropia: n = 2, anisometropias: n = 6, and congenital partial clouding of the optical axis: n = 2. The mean age of all patients at the time of the first visit to the clinic (EV) was 61 ± 12 (37-86) months, with no significant difference in the sub-groups (n > 2) except for the comparison microstrabismus/anisomyopia (p = 0.05). The mean period of the follow-up examinations, obtained with the aid of a survey of the doctors performing these examinations, was 5 years and 10 months ± 4 years and 6 months (6-253 months).

Central fixation was achieved for 20 of 32 (63%) of the patients: for 10 of 12 children with infantile esotropia, 1 of 2 children with secondary sensory esotropia, 3 of 10 children with microesotropia, and 5 of 6 children with anisometropia and 1 (already with standard occlusion) of 2 children with partial clouding of the optical axis. The mean time required to achieve central fixation was 4.5 ± 3.6 (1-11) months. The poorest success rate was found for slightly nasal excentric fixation or fixation on the nasal macular wall, and the best rate for fixation on the temporal macular wall, above the foveola or above the papilla. Achieving central fixation correlated significantly--inversely proportional--to the level of refraction of the amblyopic eye (r = -0.4, p = 0.03), as well as with the difference between the refraction of the amblyopic eye and the dominant eye (r = -0.4, p = 0.02) and with the occurrence of astigmatism in the amblyopic eye (r = -0.4, p = 0.04).

The typical age at the time of the first visit to the clinic in this study was around 5 years for most of the excentric fixations investigated. This requires greater intervention of occlusion therapy. In this study, the patients with anisomyopia and infantile esotropia showed the best success rates, and the children with microstrabismus showed the poorest success rates. The fixations close to the papilla, temporal macular wall, and over the foveola were shown to be favourable in relation to the prognosis. With microstrabism, a quasi-burned in nasal excentric fixation with binocularity dominated the unsuccessful attempts. With the primary forms of esotropia, a highly hyperopic amblyopic eye is unfavourable in relation to the prognosis.