Large-angle Strabismus Research Articles

Binocular visual perception in strabismics studied by means of visual evoked responses.

Ten normal subjects and 14 patients with comitant esotropia were examined by means of pattern visual evoked responses (VER) under monocular and binocular viewing conditions. When both eyes were stimulated together a VER summation was noted both in normals and in strabismics with small-angle deviation and anomalous retinal correspondence (ARC). This is considered as an objective proof of binocularity. Patients with large-angle strabismus and/or suppression of the image of the deviated eye did not show summation. The significance of summation and its relationship with binocular vision was analyzed by recording binocular VER in normals in which diplopia was artificially induced and in strabismics who spontaneously exhibited double vision. A simple way for differentiating normals from strabismics by means of VERs is presented, considering that the presence or absence of summation per se does not achieve this result. This method is based on the anteposition in front of the fixing eye of neutral filters of increasing density. Summation disappears in strabismics with much weaker filters than in normals (0.5 versus 1.6 log. unit).

PROGRESS IN INFANT STRABISMUS THERAPY ANALYSIS OF LONG TERM RESULTS

Summary The infant cases in 25 years of orthoptic practice have been selected for review. They comprise 750 infants among 5,497 patients seen by a single examiner during the period, 1952–1976. For the purpose of comparison, the review has been divided into three main time spans and has been analysed in relation to initial presentation treatment and results. A serious delay between onset and presentation has been documented, with evidence of recent improvement. Such delay is shown to be quite unwarranted and its elimination offers opportunity for major improvement in results. Results in large angle strabismus have shown no improvement over the period, in spite of improving techniques of diagnosis and treatment, but very considerable improvement in overall results has accompanied a marked fall in the proportion of large angle strabismus. This is attributed to earlier detection of strabismus while the angle is still small and intermittent and, to a lesser extent, to improved methods of treatment involving less use of glasses and surgery. The sensitive period for human binocular extinction is shown to taper off above the age of two years.