Update

This page will have abstracts of articles from recent literature, mainly on strabismology and related subjects but there will be a few abstracts on general ophthalmology also. They will be changed every month starting January 2001. This installment of updates contains abstracts on strabismology from the presentations at the 8th meeting of the International Strabismological Association. This meeting was held at Maastricht, The Netherlands in August 1998. The presentations have been published in a book called "Advances in Strabismology", proceedings of the VIII meeting of the International Strabismological Association, edited by Gunnar Lennerstrand, 1999, published by Aeolus Press, Science Publishers, Buren, The Netherlands. However, I have taken the abstracts from the final program given at the conference, and not from this publication.

Abstracts of some presentations on amblyopia and sensory function

1. Assessment of detection, resolution and recognition acuities in children aged 3 « years - 6 years with normal vision, visual impairment due to ocular disease and strabismic amblyopia (Authors: Agneta Rydberg and Gunnar Lennersrand, Sweden): Aim of the study was to assess the reliability and validity of different tests. Results: With Sycar rolling balls visual acuity could be assessed only roughly With preferential looking there was an overestimation of the visual acuity in all the groups. HVOT and other similar tests gave slightly higher visual acuity values than did optotypes in rows. The crowding ratio is calculated by dividing the single letter acuity by linear acuity or by dividing the grating acuity by the optotype linear acuity. It was highest in strabismic amblyopia although there were variations in different groups. Conclusions: Reliable tests were only obtained by recognition tests of linear acuity.
2. Retinal Nerve fiber layer (RNF) thickness in human strabismic amblyopia (Authors: T. P. Colen, J.T.H.N. de Fabre et al, Rotterdam, The Netherlands): Amblyopia is characterized by histopathological changes in the visual cortex and the lateral geniculate nucleus. This study was aimed at comparing the thickness of NFL in the normal eyes with that in the eye with strabismic amblyopia. The nerve fibre analyzer was used for this purpose. Conclusions: No difference was found between the amblyopic and the sound eyes.
3. Visual prognosis in children with bilateral high refractive errors (Authors: Alan Mulvihill, G. Schelit et al, Strabismus and Pediatric service, Moorfields Eye Hospital, London, UK): Results and conclusions: Usually about 10-12 months were required for the maximum visual improvement which was 6/9 in 7 out of 7 children with astigmatism (+/- 1.5 D), in 7 out of 9 cases of high myopia (-3 D or higher) and in only 12 out of 21 patients with high hyperopia (+6 or higher). The prognosis was therefore worst in high hypermetropia mainly because of its association with esotropia and/or anisometropia.
4. Binocular visual field of strabismus measured by starlight test (Authors: Toshi Hirai, Yasuki Ito et al): The test is similar to Bagolini Striated Glasses Test (BSGT). The difference is in the number of light sources. In this test there were 3 lights, one each placed in each of the 3 horizontal cardinal directions of gaze. The patients could see a grid like pattern of lights. Results: The central light stimulated the fixation light while the peripheral lights stimulated the peripheral retina. The eyes showing total suppression on BSGT were found to be participating in the binocular vision in this test. The pattern of binocular interaction changed, even minute by minute. Monocular visual fields were observed within the binocular fields.
5. Long-term wearing of prisms- a conservative way to cure squint deviations in childhood (Authors: Strangler-Zuschrott Elfriede, Austria): It has been often seen during long-term follow ups of strabismic patients that there is a spontaneous reduction in the angle of squint or there is a consecutive exotropia following strabismus surgery. One wonders if surgery is resorted to too often in childhood. Methods: 43 cases of esotropia or exotropia without amblyopia, age: 2-17 years old, squint angle 14-40 PD, all wearing full refractive correction and Fresnel prisms to produce sensory alignment for distance and near, were followed up for 2-8 years. The power of the prisms was reduced gradually during this period. Results: About 60% had orthotropia or microtropia, 18.5% improved and 20% showed no or even a negative effect. Conclusion: Long-term treatment of squint by keeping them aligned with prisms led to a significant improvement in a significant number of cases.