Acta Estrabológica
LONGLU Z, HONGKUI Z
ESTEREOPSIS, AMBLIOPÍA Y ESTRABISMO EN LOS NIÑOS DE CHINA
STEREOACUITY AND AMBLYOPIA AND STRABISMUS OF CHILDREN IN CHINA
INTRODUCTION
Thank you, Mr. Chairman.
First of all, I offered all of you, dear colleague, my congratulations on the 25th Anniversary of Spanish Society of Strabismus.
This morning, I would like to report a stereoacuity and amblyopia and strabismus of children in China. It is including two parts, part 1: studying stereoacuity of normal Chinese pre-school children, and part 2: observing stereopsis of patients with amblyopia and/or strabismus.
In part 1, the purpose of this study was to discover a developing status of stereoacuity of normal Chinese pre-school children and the relationship between stereoacuity and sex.
In part 2, the purpose of this work was to observe the impairment of stereopsis of patients with amblyopia and strabismus in detail, and to probe preliminarily into the availability of The Chinese Random-dot Stereograms for amblyopia screening among children in population
METHODS
PART 1. In this study, the random sampling were used. The stereoacuity of 473 normal children (232 boys and 241 girls), aged 4-6, were studied. The examinees were tested with five screening items.
Their both the right and left eyes are naked visual acuity of 1.0 separately. They are no colour blindness. All of them have passed the Worth Four Dot Test (4). Their external ocular structures are normal. No deviation of OD or OS is present using corneal light reflex and cover test.
PART 2. In this work, 122 consecutive patients with confirmed diagnosis of amblyopia and strabismus seen in a ophthalmology clinic were enrolled. Among the 122 cases (63 male and 59 female), 103 cases are amblyopia including 42 strabismic amblyopia, 19 cases are concomitant strabismus with normal visual acuity of _1.0.
The general routine eye examination, visual acuity at distance and near, measurement of the refractive power, determination of fixation behavior using Visuscope, prism- cover test, major amblyoscope, determination of dominant eye, were performed. According to the article of the Chinese Society of Prophytaxis and Treatment of Amblyopia and Strabismus, the following are standards for classification of amblyopia deepness. The amblyopia with corrected visual acuity _0.1 is high degree, the corrected visual acuity of 0.2¸0.6 is medium degree, 0.6 ¸0.8 is light (5,6).
The Chinese Random-dot Stereograms (7), designed by Drs. Yan Shaoming and Zheng Zhuying, were used in the study of both the part 1 and part 2. By the way, in our department, the comparison among the Chinese Random-dot Stereograms, Titmus Circles Tests and TNO Tests in examining stereoacuity has been observed and the article on the object have been published (8). In comparing these three tests, the auto-control were used.We see that all 60 youngsters (100.0% ) passed 60'' level by using three tests separately.
RESULTS
PART 1. The measurement results of stereoacuity of 473 normal Chinese pre-school children are shown in table I. The authors found that 465 children (98.3%) passed the 120'' level and 402 (85.0%) passed the 60'' level.
The distributions of stereoacuity of both 232 boys and 241 girls are shown in table II. There was no noticeable difference in the stereoacuity between the male and female pre-school children (p>0.05).
PART 2. The measurement results of stereoacuity of 122 patients with amblyopia and strabismus are shown in table III. It was found that 100 cases (82.0%) had not stereoscopic vision among 122 cases with amblyopia and strabismus. 13 cases (68.4%) were stereoblinds among 19 cases with concomitant strabismus with normal ambiocular visual acuity _1.0. But 4 amblyopes (3.9%) passed the 60'' level among 103 amblyopes.
The relationship between stereopsis and amblyopia is presented in table IV in detail. Notice that the more severe the deepness of amblyopia, the more severe the impairment of stereopsis (p<0.01). The impairment of stereopsis is correlative with the type of fixation and strabismic amblyopia (p<0.05). There was no noticeable difference in the stereopsis between the uniocular and binocular amblyopes (p>0.05).
The relationship between stereopsis and strabismus is presented in table V. It was observed that the impairment of stereopsis was due to concomitant esotropia is more severe than was due to concomitant exotropia (p<0.01).
CONCLUSION
PART 1. In this study, all 473 normal Chinese pre-school children passed the 400'' level, and 467 children (98.7%) passed the 200'' level, and 402 (85.0%) passed the 60'' level. The stereoscopic vision were classified into Foveal Stereopsis (stereoacuity of 15''¸60''), Macular stereopsis (stereoacuity of 80''¸200''), and Peripheral Stereopsis (stereoacuity of 400''¸30,000''). So the measurement results showed that 98.7% of normal Chinese pre-school children have had the macular stereopsis, and 85.0% have had the foveal stereopsis. At the same time, it was found that the stereoacuity is not correlative with sex (p>0.05).
PART 2. In this clinical observation, it was discovered that among 103 amblyopes, 93 cases (90.3%) were stereoblinds (87 cases) and/or poor (_400 seconds) stereopsis (6 cases). Notice that among 19 patients with concomitant strabismus with normal visual acuity _1.0, 14 patients (73.7%) were stereoblinds (13 cases) and poor (_400 seconds) stereopsis (1 cases) also.
In addition, the more severe the deepness of amblyopia, the more severe the impairment of stereopsis (p<0.01). The impairment of stereopsis is correlative with the typeof fixation and strabismic amblyopia (p<0.05), and is not correlative with the uniocular or binocular amblyopes (p>0.05). The impairment of stereopsis was due to concomitant esotropia is more severe than was due to concomitant exotropia (p<0.01).
At the same time, among 103 patients with confirmed diagnosis of amblyopia, it was discovered 87 amblyopes with stereoblind. So that, the detectable rate of stereoblind using the Chinese Random- dot Stereograms is 84.5%. But 8.7% of amblyopes passed 120'' level, and 3.9% can passed 60'' and 30'' level. Notice it when only using the Chinese Random-dot stereograms for amblyopia screening.
In summary, I would conclude that the developing status of stereoacuity of normal Chinese pre-school children are good. The impairment of stereopsis of patients with amblyopia and strabismus are severe. And the Chinese Random- dot Stereograms for amblyopia screening among children in population is available.
REFERENCES
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