Research of near stereopsis in clinical treated amblyopes / 安徽医科大学学报

104 successful treated amblyopes were screened from the ophthalmology outpatient departmt,who had successfully amblyopia treatment,all with the corrective visual acuity around 0.8 and the visual acuity of two eyes were less than two lines.Titmus stereogram was used to test stereoacuity,the chi-square test was used to analyze the results.There was statistical significance between the three types of amblyopia(x2 =11.294,P ＜ 0.05),individuals with ametropic amblyopia have better stereoacuity than others,individuals with anisometropic amblyopia and strabismic amblyopia have worse stereoacuity than others;There was statistical significance between different degrees of amblyopia (x2 =13.455,P ＜ 0.05),individuals with mild and moderate amblyopia have better stereoacuity than others,individuals with severe amblyopia have worse stereoacuity than others;There was statistical significance between differentdiagnosed age (x2 =11.263,P ＜ 0.05),the first diagnosed age less than 7 years old was better than over 7 years old;No difference was identified between thestereoacuity of monocular and binocular amblyopia.The visual acuity of different kinds of amblyopia could recover to normal level after regular amblyopia treatment,however,the stereoacuity has not recovered to normal level,it is necessary to take exercise to improve binocular function.As a result,the stereoacuity is considered to be a standard to evaluate the effect of amblyopia treatment.

The Surgical Outcome of Intermittent Exotropia with Good Binocular Function

PURPOSE: We investigated the success rate of surgery and binocular function after surgery in intermittent exotropia with good preoperative binocular function. METHODS: Thirty-eight intermittent exotropia patients who had good stereopsis of 40 seconds according to the Titmus test, showed fusion by Worth-4-dot test preoperatively, and had at least 1 year of postoperative follow-up were included in the present study. The age at operation, angle of exodeviation, visual acuity, stereopsis with Titmus test and fusional status with Worth-4-dot test after surgery were analyzed. A surgical success was defined as postoperative angle of deviation less than 10 prism diopter (PD). RESULTS: The patient mean age at the time of the operation was 7.9 years. The mean preoperative angle of exodeviation was 25.5 PD at far distance and 27.5 PD at near distance. The mean follow-up time was 22.9 months. The success rate of surgery was 81.6% at 6 months, 68.4% at 1 year and 60.5% on the last visit. Seventeen patients (44.7%) had stereopsis of 40 seconds and showed fusion at far and near distance after surgery. The stereopsis was worse than 100 seconds in 2 patients (5.3%), and fusion was maintained at only near distance in 15 patients (39.5%). In 7 patients (18.4%), the stereopsis decreased to 200 seconds or worse, or there was no fusion after surgery. CONCLUSIONS: The recurrence of exodeviation was a major cause of the surgical failure in the intermittent exotropia with good preoperative binocular function. Moreover, binocular function may decrease postoperatively in intermittent exotropia with good preoperative binocular function, so careful follow-up may be required to maintain this function.

Long-Standing Intermittent Exotropia Diagnosed in Patients Older than 16 Years of Age

PURPOSE: To evaluate clinical features and binocular function of long-standing intermittent exotropia detected for the first time in patients older than 16 years of age. METHODS: We retrospectively evaluated adult exotropic patients older than 16 years of age who were first diagnosed between March 2001 and February 2010. A total of 73 patients with exotropia who had not undergone ophthalmologic management for at least 10 years were included in the present study. RESULTS: The mean age was 29.47 +/- 12.13 years and 42 (57.5%) patients were male. The mean angle of deviation was 40.68 +/- 17.75 prism diopter (PD); 46.58% of patients were between 30 to 50 PD and 26% were over 55 PD. Out Of 64 the intermittent exotropic patients, 17 patients had poor fusion at distance. Abnormal findings in binocular function such as poor stereoacuity, suppression at distance, reduced binocular visual acuity at distance, diplopia, panoramic vision, anomalous retinal correspondence, and accommodative spasms were observed. All 20 patients received surgery. Postoperatively, 59.90% of the patients showed improvement in near stereoacuity, and 78.57% improved in suppression at distance. CONCLUSIONS: According to the present study, exotropia may cause subjective and objective deteriorations in motor/sensory function without appropriate medical or surgical intervention during childhood. In addition, the potential for improvement in binocular function after surgery was demonstrated even in adults. Therefore, we recommend surgical treatment for untreated, long-standing exotropia in adults.

The Change of Sensory Binocularity according to the Surgical Results in Intermittent Exotropia

PURPOSE: This study was designed to determine which sensory test best reflects the improvement of binocular function according to the surgical outcome of intermittent exotropia METHODS: We examined the visual acuity, refractive error, angle of exodeviation, fusional status with the Worth-4-dot, Bagolini tests and stereoacuity with the Titmus test preoperatively in 61 intermittent exodeviation patients who had undergone the bilateral lateral rectus recession operation from February 2002 to 2003 July. We compared the binocularity tests between the two groups: esodeviated and orthotropic or exodeviated. RESULTS: The average improvement time of the Bagolini, Worth 4 dot and Titmus tests was 0.54 +/- 1.2, 2.03 +/- 2.90, 1.12 +/- 2.1 weeks, respectively. Although the shortest time was for the Bagolini test (p=0.001), the Titmus test was more sensitive. CONCLUSIONS: The high variability of the binocularity tests should be remembered and take into account when we interpret the test results.

The Comparison of Binocular Function of Basic and Simulated Divergence Excess Type in Intermittent Exotropia

PURPOSE: The purpose of this study was to evaluate and compare the binocular function in patients with basic and simulated divergence excess types of intermittent exotropia [X(T)]. METHODS: Seventy-seven patients, 46 basic type and 31 simulated divergence excess type, were studied by Worth 4-dot test (W4D), Polarized 4-dot test (P4D), Titmus test, and distance stereoacuity test using Mentor B-VAT(R)II videoacuity tester. RESULTS: Near W4D, distant W4D and distant P4D were fused in 71.7%, 8.6% and 52.2% in basic type and in 100%, 25.8% and 87.1% in simulated divergence excess type, respectively. The fusion rate in simulated divergence excess type was significantly higher, than in basic type (P=0.001, 0.04, 0.001). However, the difference in near P4D between the two types was not significant (P=0.24). In distance stereoacuity test, basic type showed 272 seconds and simulated divergence excess type showed 177 seconds, showing a significant difference (P=0.02). There was no significant difference in near stereoacuity between the two types (P=0.08). CONCLUSIONS: The study demonstrated a difference in binocular function in patients with basic and simulated divergence excess types of X(T). A better binocular function was observed in the latter group.

Clinical Significance of Refixation Time in Intermittent Exotropia

PURPOSE: We compared the clinical significance of refixation time with other visual function tests in the aspect of the operation success rate in the intermittent exotropia patients. METHODS: This study included 40 intermittent exotropia patients who received bilateral lateral rectus muscle recession from August 2001 to March 2002. We evaluated pre-operation corrected vision, deviation angle, axial length, Worth 4 dot test and titmus test. We also checked refixation time for which deviated eye return to orthophoric position. And we observed their progress for at least 6 months. RESULTS: Refixation time was significantly(P<0.05) correlated with deviation angle. Refixation time corrected by deviation angle was defined as corrected refixation time and it was significantly(P<0.05) short in non-amblyopia group, good stereopsis group and fusion group than amblyopia group, poor stereopsis group and non-fusion group. Also it was observed to be short in success group than in failure group(P<0.05). CONCLUSIONS: Because refixation time is relative easy to measure without specific equipment, refixation time should be used in patients who are poorly-cooperated and difficult to measure binocualr function with the degree of strabismus. And it may be considered a factor that affects operation success rate.

The Relationship between Binocular Function and the Surgical Outcome of Intermittent Exotropia

PURPOSE: This study was designed to determine the relationship between binocular function and the surgical outcome of intermittent exotropia. METHODS: The surgical outcome and binocular function were retrospectively investigated in 44 patients who had undergone surgery for intermittent exotropia with at least 6 months of post-operative follow-up. We evaluated visual acuity, age at operation, angle of exodeviation, fusional status with Worth-4-dot test and stereoacuity with Titmus test before and after surgery. RESULTS: A 'surgical success' defined as a final alignment of orthophoria, esotropia less than 5PD or exotropia less than 10PD at far primary position, was achieved in 31 patients (70%). The surgical outcome according to preoperative stereopsis and fusional status was not statistically significant. Whereas, there was a tendency toward more surgical success in patients with central fusion and the first postoperative day diplopia but statistically indifferent. There was an improvement of stereoacuity in 34 out of 44 patients after surgery. The fusional status was improved in 9 patients out of 44 patients. There was an improvement of postoperative binocular function regardless the surgical outcome. But the achievement of fine stereopsis below 100 seconds of arc and central fusion increased only in success group. CONCLUSIONS: The preoperative binocular function did not contribute significantly to the surgical outcome (p>0.05) and postoperative binocular function could be improved by surgical correction in both surgical success and failure group. But the better binocular function was achieved by successful surgical alignment.

Effect of Experimentally Induced Anisometropia on Binocular Vision

We investigated the effect of experimentally induced anisometropia on binocular function. Unilateral myopia, hyperopia, or astigmatism(Axis 90degrees) was induced in eighteen adults with normal binocular function using softcontact lenses. Sensory status was assessed by measuring stereoacuity, Worth four dot test, and Bagolini lens test. Binocular function of all subjects decreased with increasing levels of anisometropia. In Worth four dot test, foveal suppression increased in proportion to the levels of anisometropia. Stereoacuity was similarly degraded by the induced anisometropia. Bagolinilens responses were normal in almost all subjects. Our study suggest that experimentally induced anisometropia cause significant abnormalities in binocular function in adults.

Stereopsis after Surgery in Longstanding Adult Horizontal Strabismus

Binocular function is not easy to obtain after strabismus surgery in adults with longstanding strabismus. In this study, postoperative binocular function was evaluated in 60 adults with longstanding horizontal strabismus. The subjects were eighteen years older and had developed strabismus before the age of eight. They were composed of 15 esotropes and 45exotropes without history of strabismus surgery. Pre-and postoperative stereopsis was assessed with Titmus-fly and Randot stereopsis tests. Visual acuity of the deviating eye, duration of deviation, angle of deviation, and status of stereopsis were compared according to the type of deviation. Stereopsis was shown in 20.0% of esotropes and 71.1% of exotropes before surgery. After surgery, only 46.7% of esotropes showed stereopsis in contrast with 91.1% of exotropes. In cases with congenital origin, 22.2% of esotropes and 83.3% of exotropes had stereopsis, while in those of acquired origin, 83.3%, and 92.3%, respectively. This study shows that stereopsis of good quality can be obtained and improved after surgery in adlts with longstanding horizontal strabismus except congenital esotropes. Higher gain of good postoperative stereopsis was related to better visual acuity of the deviating eye and shorter duration of deviation.