Monocular and binocular reading performance in children with microstrabismic amblyopia.

AIM: To evaluate if functionally relevant deficits in reading performance exist in children with essential microstrabismic amblyopia by comparing the monocular and binocular reading performance with the reading performance of normal sighted children with full visual acuity in both eyes. METHODS: The reading performance of 40 children (mean age 11.6 (SD 1.4) years) was evaluated monocularly and binocularly in randomised order, using standardised reading charts for the simultaneous determination of reading acuity and speed. 20 of the tested children were under treatment for unilateral microstrabismic amblyopia (visual acuity in the amblyopic eyes: logMAR 0.19 (0.15); fellow eyes -0.1 (0.07)); the others were normal sighted controls (visual acuity in the right eyes -0.04 (0.15); left eyes -0.08 (0.07)). RESULTS: In respect of the binocular maximum reading speed (MRS), significant differences were found between the children with microstrabismic amblyopia and the normal controls (p = 0.03): whereas the controls achieved a binocular MRS of 200.4 (11) wpm (words per minute), the children with unilateral amblyopia achieved only a binocular MRS of 172.9 (43.9) wpm. No significant differences between the two groups were found in respect of the binocular logMAR visual acuity and reading acuity (p>0.05). For the monocular reading performance, significant impairment was found in the amblyopic eyes, whereas no significant differences were found between the sound fellow eyes of the amblyopic children and the control group. CONCLUSION: In binocular MRS, significant differences could be found between children with microstrabismic amblyopia and normal controls. This result indicates the presence of a functionally relevant reading impairment, even though the binocular visual acuity and reading acuity were both comparable with the control group.

Evaluating reading acuity and speed in children with microstrabismic amblyopia using a standardized reading chart system.

BACKGROUND: To examine if standardized reading charts with highly comparable test items can be used for evaluating impairments in the monocular reading performance of children with microstrabismic amblyopia characterized by a small angle of squint with less than 5 degrees. METHODS: The reading performance of 22 children (mean age: 11.7+/-1.6 years) with unilateral microstrabismic amblyopia was evaluated monocularly in both eyes, using standardized reading charts for the simultaneous determination of reading acuity and speed. The print sizes of the highly comparable sentence optotypes were logarithmically graded, providing constant geometric proportions for all testing distances in order to control contour interaction. All children were under continuous amblyopia therapy. RESULTS: In the amblyopic eyes, reading acuity and maximum reading speed were significantly impaired when compared to the sound fellow eyes (P<0.001). In respect of the maximum reading speed, a mean inter-ocular difference of 33+/-19 words per minute was found, revealing functionally relevant deficits in monocular reading performance. The amblyopic eyes achieved only a significantly reduced reading acuity (mean inter-ocular difference: LogRAD 0.5+/-0.24; P<0.001). In eight children, the amblyopic eyes achieved a best-corrected visual acuity of LogMAR 0.0 or better: in respect of the visual acuity, there was no significant inter-ocular difference, but reading acuity and maximum reading speed were significantly impaired when compared to the fellow eyes. CONCLUSIONS: Microstrabismic amblyopia was associated with significant impairment of reading acuity and speed in treated amblyopes, even in those with no persistent acuity deficit. To improve treatment addressing these functional deficits, reading performance should be monitored over time using standardized reading tests, which provide essential information about functionally relevant reading impairments.

[Randomized field study of the etiology of strabismus concomitans]. / Randomisierte Feldstudie über die Atiologie des Strabismus concomitans.

After an introduction to the problems of binocular vision and an overview of the literature, the authors report on the reasons for undertaking this study and on its practical implications. Up to now, no other randomized study has been undertaken to our knowledge on children of this age group in such a large city as Vienna. All children in primary 3 classes in 20 out of the 256 elementary schools were examined ophthalmologically and orthoptically. It was found that hereditary factors are of statistically significant importance. Especially important for the ophthalmologist is also the statistically significant relation between the diagnosis poor range of fusion, poor fixation, incorrect Worth test for distance and/or proximity, and poor or lacking stereoscopic vision with the occurrence of strabism. The authors were astonished to find a remarkably high percentage of exophoria (58%), in contrast to esophoria (16%). It is interesting for prophylaxis and therapy that children originating from families where spectacles are worn, acted more cooperatively and tended to take the orders of the physician more seriously than those coming from families without eye problems. The promotion of genetic research related to squint and more counselling for couples wishing to have children or confronted with risk factor problems would be desirable, as well as the inclusion of more obligatory ophthalmological examinations in the mother-child medical "passport".