Evaluation of dynamic stereopsis in intermittent exotropia patients.

AIM: To delineate the characteristics of the dynamic stereopsis test and analyze related parameters in intermittent exotropia [X(T)] patients. METHODS: Fifty-seven X(T) patients and 55 normal subjects were enrolled in this study. The normal and X(T) groups were used to test the reproducibility and reliability of the dynamic stereopsis test, and Bangerter filters with densities of 0.2 were then used to simulate suppression to test for traditional and dynamic stereopsis. In the X(T) group, the measurements included 1) dynamic stereopsis test comprising three parts: motion+disparity, motion only and disparity only; 2) ocular deviation angle; 3) Bagolini striated lens test; 4) disease course; and 5) Titmus stereopsis test. RESULTS: The test-retest reliability of the dynamic stereopsis method was 0.901 in the normal and X(T) groups, and none of the X(T) patients were able to pass the static and dynamic stereopsis tests after using the 0.2 Bangerter filter. The accuracy rate was greater than 80% in the normal group and 31.81%, 36.36%, and 45.45% for the motion+disparity, motion-only and disparity-only components of the traditional test for X(T) patients diagnosed with stereoblindness via traditional tests, respectively. Patients with a long disease course (>1y) had worse dynamic stereopsis than those with a short disease course (<1y; P<0.05, Chi-square test). The deviation angle was not correlated with the motion+disparity, disparity-only, or the motion-only test components (all P>0.05, Chi-square test). CONCLUSION: Dynamic stereopsis is preserved in certain X(T) patients diagnosed with stereoblindness via traditional tests. A long disease course was shown to be a negative factor for dynamic stereopsis in X(T) patients which might be associated with worse progression, and provide good references clinically.

Long-term visual outcome of dense bilateral congenital cataract.

BACKGROUND: Dense congenital cataracts often cause severe visual impairment. The results of long-term follow-up of dense bilateral congenital cataract in China have not been well documented. The purpose of this study was to evaluate the long-term visual function in children who underwent cataract extraction for dense bilateral congenital cataract in southern part of China. METHODS: Medical records of children who underwent surgery of dense bilateral congenital cataract between January 1992 and December 2000 at Zhongshan Ophthalmic Center of Sun Yat-sen University were retroactively reviewed. In 38 children available for current follow-up, best corrected visual acuity (BCVA) and stereoscopic vision, as well as nystagmus, strabismus, and other complications, were evaluated. The mean follow-up period was 107.6 months (range 60 to 167 months). RESULTS: The mean age of cataract extraction and secondary intraocular lens implantation were 5.6 months (range 3 to 12 months) and 4.2 years (range 2.4 to 15 years), respectively. The mean BCVA was 0.25 in the better eye and 0.16 in the fellow eye. Stereoscopic vision was absent in all patients, and 3 children had simultaneous perception. Nystagmus was detected in all cases and strabismus in 35 cases. A high correlation was found between timing of cataract extraction and final BCVA of the better eye (r = -0.55, P = 0.00). A statistically significant difference was found in BCVA between post- and pre-treatment of amblyopia (t = 5.65, P = 0.00). CONCLUSIONS: Long-term visual function in children with dense bilateral congenital cataract was poor when cataract surgery was performed at age of 3 months or later. Earlier cataract surgery with adequate optical rehabilitation contributed to better visual outcome.

[Development and evaluation of the scale of quality of life for children with bilateral congenital cataract].

OBJECTIVE: To develop and evaluate the 23-item quality of life (QoL) 125 scale contained four subscales for children with bilateral congenital cataract. METHODS: 18 children with normal visual acuity and 76 patients with congenital bilateral cataract (age range of 8 years to 15 years) were evaluated with QoL. The 23-item QoL scale contained the following subscales: visual function, self-care, sociality, and mentality. Dispersion, correlation coefficient, factor analysis, discrimination analysis, Cronbach alpha and test-retest reliability were applied to select the parameters and data analysis. RESULTS: The new scale included 20 items after screening. The correlation coefficients of content validity of each item and subscale were beyond 0.6 (P < 0.05). Statistically significant difference was found at discrimination analysis between normal and cataract children (P' = 0.000), the differences was also demonstrated between preoperative and postoperative cataract children (P' = 0.000). The coefficient of test-retest reliability was 0.895 (P = 0.000), and the Cronbach's alpha coefficients of four subscales were 0.822, 0.922, 0.797, and 0.794 respectively. The statistics value of effective size was 1.141. CONCLUSIONS: significant reliability, validity and responsibility to change life quality were achieved in the 20-item scale of QoL for children with bilateral congenital cataract. This scale can be applied to evaluate the life quality of bilateral cataract children.

[The clinical features and surgical treatment of masked bilateral superior oblique palsy].

OBJECTIVE: To investigate the clinical features, diagnosis and the management of masked bilateral superior oblique palsy (MBSOP). METHODS: Retrospectively analyzed the records of all 7 patients that met the clinical criteria for MBSOP in Zhongshan Ophthalmic Center between 1999 and 2003. The head tilt, vertical deviation in primary position and the action of obliquus pre- and postoperatively were collected in detail. RESULTS: All 7 patients were diagnosed as unilateral SOP in the first time. The average hypertropia in primary position preoperatively was 19.7(Delta) (range 6(Delta) to 30(Delta)). All patients had a head tilt, obvious unilateral inferior oblique overaction (+2 to +4) and mild superior oblique underaction (-1 to -2), and normal action in contralateral superior and inferior obliquus. Initial surgery consisted of ipsilateral inferior oblique weakening with (5 patients) or without (2 patients) ipsilateral superior rectus recession. The average hypertropia in primary position was 12.0(Delta) (range 0(Delta) to 20(Delta)) after the first operation. In 1 week to 4 years, all of the previously masked eye presented the inferior oblique overaction (+2 to +3) and superior oblique underaction (0 to -1). All patients underwent a second surgery in 4 months to 4 years after the initial surgery. The average hypertropia in primary position was 2.3(Delta) (range 0(Delta) to 7(Delta)) after the second operation. Postoperative alignment was excellent in all patients. CONCLUSIONS: Masked bilateral superior oblique palsy is quite difficult to detect before surgical correction of the initial manifest palsy. The possibility of an occult contralateral palsy should be considered in all undergoing surgery for unilateral SOP. The superior rectus recession and the inferior oblique weakening procedure should be performed at different stages. When the masked palsy becomes evident, a successful surgical outcome can usually be expected.

[Quality of life assessment in children with congenital bilateral cataract].

OBJECTIVE: To study the influence of congenital bilateral cataract on visual-related quality of life (QoL) in children. METHODS: The scale of QoL for children with congenital bilateral cataract was used to evaluate the QoL of 81 children with congenital bilateral cataract and 28 healthy children with normal visual acuity. The average age of congenital bilateral cataract candidates was 9.8 years (from 8 to 15 years) and 37 patients were female. Thirty-six cataract children took part in the both preoperative and postoperative investigations. The patients' QoL were also categorized by age, gender, score, visual acuity, surgery and density of cataract. Multiple-linear regression model was applied to analyze the influence factors of QoL. RESULTS: Statistically significant difference was found at the QoL between healthy children and children with congenital bilateral cataract (P = 0.00). The QoL in children with non-dense cataract was increased after cataract surgery (P = 0.00). A high correlation was found between visual acuity and QoL (r = 0.53, P = 0.00). A statistically significant difference was found in QoL between dense and non-dense cataract (P = 0.00). Three variances enrolled in the multiple-linear regression equation included the density of cataract, surgery and visual acuity. Their partial regression coefficients were 6.14 (P = 0.00), 3.21 (P = 0.01) and 1.07 (P = 0.01) respectively. CONCLUSIONS: Compared with the healthy children, the QoL score was severely impaired in children with congenital bilateral cataract, which was influenced by the density of cataract, surgery and visual acuity. Visual acuity is the most critical factor influencing the QoL.

[The effect of weakening the overaction superior oblique muscles on the status of ocular torsion].

OBJECTIVE: To investigate the effect of weakening the superior oblique muscles on the status of ocular torsion. METHODS: Twenty-nine patients (58 eyes) underwent tenotomy or partial ectomy of bilateral superior oblique muscles for treatment of superior oblique overacting. Objective cyclodeviations were assessed by fundus photograph before and 7 days after the surgery. The photographs were transferred to a computer and then the fovea-disc angle was measured by a software for drawing pictures. Subjective cyclodeviations and binocular vision function were assessed by synoptophore. RESULTS: Fundus photography before surgery revealed that the intorsion was 10.48 degrees +/- 6.01 degrees for the right eye and was 9.37 degrees +/- 5.88 degrees for the left eye. The reduction of the cyclodeviations by weakening the superior oblique muscle for the right and left eye was 9.11 degrees +/- 7.09 degrees and 7.94 degrees +/- 4.76 degrees respectively. The comparisons of objective ocular torsion for both eyes showed high significant differences (P < 0.01) pre- and post-operatively. There were no significant differences (P > 0.05) between the effects of tenotomy or partial ectomy of bilateral superior oblique muscles. All patients showed no cyclotropia and normal binocular vision function was obtained with synoptophore before and after surgery. CONCLUSIONS: Weakening the overaction superior oblique could correct ocular incyclodeviation. Both tenotomy and partial ectomy of bilateral superior oblique muscles can treat ocular incyclodeviation effectively. The changes of subjective and objective cyclodeviations are inconsistent with each other.

[Clinical features of V patterns strabismus and its long-term effect of surgical treatment].

OBJECTIVE: To investigate the features and treatment of V patterns strabismus. METHODS: Pre- and post-operative deviation and oblique muscle action as well as binocular visual function were evaluated in sixty-three V pattern patients. The difference between upgaze and downgaze of deviation were recorded before and after operation. RESULTS: Sixty-two patients (98.4%) with binocular or unilateral inferior oblique overaction + 2 to + 3 were treated with inferior oblique weakening procedure and horizontal rectus recession-resection procedure. 1 patient with binocular inferior oblique overaction + 1 treated with horizontal recti recession-resection procedure. The difference between upgaze and downgaze is 25.6 prism diopters (PD) preoperatively and 4.5 PD postoperatively. The primary-position exotropia preoperatively of 48 V pattern exotropia is 37.2 PD, after surgery, the average deviation is 3.4 PD of esotropia [38 cases (79.2%) with deviation within +/- 10 PD]. 15 cases of V pattern esotropia had deviation 50.6 PD preoperatively, after surgery, the average deviation is 2.4 PD of esotropia [11 cases (73.3%) with deviation within 10 PD]. 21 patients (33.3%) obtained stereo visual function after surgery. CONCLUSION: V patterns always had inferior oblique over action and could be treated with the inferior oblique weakening procedure. The primary-position deviation should be treated by traditional horizontal rectus recession-resection procedure. The stereoscopic function had a good prognosis with surgery.

[The effect of weakening inferior oblique muscles on the status of ocular torsion].

OBJECTIVE: To understand the clinical significance of subjective and objective examination of cyclodeviations and investigate the effect of weakening inferior oblique muscles on the status of ocular torsion. METHODS: Twenty patients (40 eyes) with overacting inferior oblique muscles underwent bilateral myotomy or partial myectomy of inferior oblique muscles. Subjective cyclodeviations were measured before surgery as well as one week, two months after surgery by double maddox rod test (DMRT). Objective cyclodeviations were assessed by fundus photography before and 7 days after surgery in 15 cases. The photograph was transferred to a computer, and the fovea-disc angle was measured by means of drawing picture software. RESULTS: Nine patients with primary overaction of inferior oblique muscles were negative with DMRT before surgery, and only one case revealed incyclotropia 5.0 degrees tested two months after surgery. Four out of 11 patients with secondary overaction of inferior oblique muscles showed excyclotropia 2.5 degrees - 5.0 degrees with DMRT before surgery, and all patients indicated no subjective cyclotropia with DMRT two months after surgery. Fundus photography determination of the right eye revealed extorsion 16.83 degrees +/- 6.39 degrees, the left eye 14.92 degrees +/- 4.51 degrees before surgery. The reduction of the cyclodeviations by weakening inferior oblique muscle for the right and left eye was 13.07 degrees +/- 3.38 degrees and 10.54 degrees +/- 3.75 degrees respectively. The comparison of objective ocular torsion for both eyes showed high significant differences (P < 0.01) pre- and post-operatively. CONCLUSIONS: The results of subjective and objective examination of cyclodeviations in patients with primary or secondary overacting inferior oblique muscle early after birth were not consistent. Weakening inferior oblique muscle could correct excyclodeviation. There exist complicated compensatory mechanisms for subjective change of ocular torsion after surgery. The changes of subjective and objective cyclodeviations are still inconsistent.

[The effect of preventing anterior segment ischemia by preservation of anterior ciliary vessels in rabbit].

OBJECTIVE: To investigate the effect of preserving anterior ciliary vessels (ACVs) on the prevention of anterior segment ischemia syndrome (ASI) during the surgery of extraocular muscles. METHODS: Thirty-two adult New Zealand white rabbits were randomly divided into four groups. ACVs of the right eyes were preserved among all of the rabbits, and were cut off in all of the left eyes. Group A: internal and external recti were cut off in two eyes; Group B: superior and inferior recti were cut off in two eyes; Group C: internal, external and superior or inferior recti were cut off in two eyes; Group D: all of the recti were cut off in two eyes. All rabbits were observed under slit microscope. The intraocular pressure (IOP), the total protein and lactic acid in the aqueous humor were recorded preoperatively and postoperatively. Eyes were enucleated at the forth week postoperatively to obtain the iris and the ciliary body for histopathologic study and electron microscopy. RESULTS: No signs of ASI were observed in the right eyes of all four groups under the slit lamp and under the light and election microscopes. The IOP and levels of ingredients of aqueous humor (total protein and lactic acid) showed no difference between preoperative and postoperative interval. No obvious ASI was observed in the left eyes of group A. Mild reactions of ASI were observed in the left eyes of group B. Moderate to severe reactions of ASI were observed in the left eyes in group C and group D. The IOP reduced from (17.21 +/- 3.76) mm Hg (1 mm Hg = 0.133 kPa) preoperatively to (14.48 +/- 3.36) mm Hg postoperatively in group C (P < 0.05); and from (16.68 +/- 2.33) mm Hg reduced to(3.17 +/- 0.92) mm Hg in group D. (P < 0.05). The level of total protein and lactic acid in the aqueous humor increased from (505.3 +/- 5.0) mg/L and (7.54 +/- 0.47) g/L preoperatively to (811.9 +/- 44.4) mg/L and (11.00 +/- 3.59) g/L postoperatively in group C, respectively (P < 0.05). In group D, the level of total protein and lactic acid in the aqueous humor increased from (504.6 +/- 4.1) mg/L and (7.17 +/- 1.44) g/L preoperatively to (1025. 8 +/- 78.3) mg/L, (8.23 +/- 1.68) g/L postoperatively, respectively (P < 0.05). There were various histopathological changes under the light and electron microscope in groups C and D. While no obvious ischemic changes were observed in group A. CONCLUSION: Two vertical muscles cut off at one eye simultaneously would produce mild reactions of ischemia, while three or more muscles cut off simultaneously could obstruct blood flow in eyes and induce ASI. Preservation of the ACVs could avoid the occurrence of ASI.

[Clinical features and surgical treatment of A-pattern exotropia].

OBJECTIVE: To investigate the clinical features of A-pattern exotropia and to evaluate the efficacy of surgical treatment for the correction of A-pattern exotropia (A-XT). METHODS: Pre- and post-operative eye position, superior oblique muscle function, clinical features and binocular function were examined and analyzed in 32 patients with A-pattern exotropia. RESULTS: Overaction of the superior oblique (SO) (31/32) and insufficiency of medial rectus muscle (20/32) were commonly seen in the group of patients. The tenectomy of the SO and the resection of the medial rectus muscle were effective in most of A-pattern exotropia. 87.5% (28/35) of A-pattern exotropia in our study were successfully corrected. Four cases got binocular function after surgery. CONCLUSIONS: Based on the clinical features and the effects of surgical treatment, we conclude that the superior oblique muscle overaction and medial rectus muscle insufficiency are the primary factors in the etiology of A-pattern exotropia that is the most common form of A-V syndrome. Weakening the overaction of superior oblique muscle combined with the correction of exotropia is an effective way to correct A-pattern exotropia.