Effects of anisometropia on binocularity.

PURPOSE: To investigate the effects of anisometropia on binocular function and the relationship between stereopsis and fusion in anisometropia. METHODS: Twenty-five patients with anisometropia were studied. The manifest refraction and best-corrected Snellen visual acuity of each patient was recorded. Patients, corrected with spectacles, were evaluated using Bagolini glasses, the 4-diopter (D) prism test, Worth four-dot test, and TNO stereotest. RESULTS: All patients indicated fusion by the Bagolini glasses. Although the 4-D prism test was positive in the anisometropic eye of all 25 patients, it was slower than the response of the other eye in 19 patients with reduced stereoacuity. On the distant Worth four-dot test, fusion response was positive in 15 patients. On theTNO test, stereoacuity levels were reduced or absent in 19 patients. CONCLUSION: The depth of amblyopia is more effective than the amount of anisometropia in causing a deterioration in binocularity. Even if fusion is weak, almost all patients with anisometropia have bifoveal fusion. Fusion becomes weak and stereoacuity decreases in proportion to the anisometropic amblyopia. Stereoacuity is related to the strength of fusion, and the TNO stereotest effectively detects those patients with significant anisometropic amblyopia.

Near stereoacuity: development in preschool children; normative values and screening for binocular vision abnormalities; a study of 115 children.

PURPOSE: Because of controversial results in previous reports, we wished to further evaluate stereoacuity development in children with normal binocular vision, and to investigate the reliability of stereoscopic tests for screening for abnormal binocular vision and amblyopia. MATERIALS AND METHODS: In a prospective study, 115 children, age 3 to 6 1/2 years, were first tested on the TNO and Titmus Stereotests, after which they received a more complete eye examination to determine the presence of ocular and vision abnormalities. Only specific quantitative stereotest results were tabulated for the development study. RESULTS: Binocular vision anomalies were detected by stereotesting in 3 of the 115 children. Testability was better on the TNO than the Titmus Stereotest. Using only the quantitative stereotest results, when segregated by age groups, there was a "statistically significant" change (improvement with age) on the TNO Test (p=.0001)(x2); whereas there was no such improvement found on the Titmus Stereotest Circles, p=.045, 0.72. CONCLUSIONS: The TNO Test is reliable for screening for binocular vision anomalies and amblyopia. Also, normal stereopsis and stereoacuity acuity improves "significantly" between age 4 and 5 1/2 years, and reaches adult-like level at 5 1/2 years on this test.

Hemodynamic changes after strabismus surgery.

AIM: The aim of this study was to investigate the hemodynamic changes that may occur in the retrobulbar circulation after strabismus surgery, using color Doppler ultrasonography (CDI). METHODS: Fifteen healthy volunteers (control group, n=15) and sixteen patients diagnosed with strabismus were enrolled in the study. Either recession or resection was planned on one horizontal rectus muscle in the eyes of Group 1 (n=11) and on two horizontal rectus muscles in the eyes of Group 2 (n=10). CDI was performed to measure peak systolic velocity (V(max)), end-diastolic velocity (V(min)) and mean blood flow velocity (V(mean)) in the ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary artery (PCA) in the control group and in Groups 1 and 2, both preoperatively and 2-7 days postoperatively. RESULTS: The postoperative resistivity indexes in Groups 1 and 2 were found to be different from those in the control group. Preoperative V(max) and postoperative V(min) and V(mean) values of the vessels in Group 2 were different from those in both Group 1 and the control group (p<0. 001). In both treatment groups, the differences between postoperative and preoperative measurements of the parameters in the OA, CRA and PCA demonstrated statistical significance (p<0.001). CONCLUSION: After strabismus surgery on the horizontal recti, there are some alterations in the retrobulbar blood flow with a significant difference between pre- and postoperative blood flow velocities after single and double rectus surgery. The clinical significance of these results needs to be determined because CDI may be a useful tool in the investigation of hemodynamic alterations after anterior segment interventions that may cause anterior segment ischemia.

Divergence paralysis & intracranial hypertension due to neurobrucellosis. A case report.

CASE REPORT: A 22 year old female presented with sudden onset of uncrossed diplopia at distance, intracranial hypertension, esotropia and was evaluated. Microbiological tests of CSF and sera showed for brucellosis and the patient received therapy for this and her intracranial hypertension. The papilledema, headache, esotropia and diplopia all disappeared after therapy. CONCLUSIONS: Diagnostic tests for brucella must be considered for patients who have divergence palsy and papilledema, especially those living in endemic areas.

Synostotic plagiocephaly causing pseudoparalysis of the superior oblique and ocular torticollis: report of a case with unique sensory findings.

PURPOSE: To report a case in which strabismus surgery did not eliminate the abnormal head posture although it did improve the vertical strabismus; and to consider the causes of this situation. CASE REPORT: The patient had a right eso-hypertropia and ocular torticollis to the left shoulder as a result of a right superior oblique mechanical deficiency, secondary to her craniosynostosis. A myectomy of the right inferior oblique muscle and a tucking procedure of the right superior oblique muscle were performed. Postoperatively, the abnormal head posture persisted, although strabismus surgery improved the vertical deviation. However, improvement of the abnormal head posture upon patching the deviated eye only indicated that the origin of the persistent abnormal head posture must be ocular. Further tests revealed that an anomalous retinal correspondence (ARC) with eccentric fixation was responsible. CONCLUSIONS: In patients with ocular torticollis, ARC with eccentric fixation must be ruled out prior to surgery as these may negatively affect the outcome.

A synthetic model for triple-helical domains in self-splicing group I introns studied by ultraviolet and circular dichroism spectroscopy.

Structural studies were performed on synthetic oligonucleotides with sequences corresponding to the P4/P6 and J3/4, J6/7 regions of the self-splicing group I intron of the bacteriophage T4 nrdB pre-mRNA, which correspond to the proposed triple-helical domain in the Tetrahymena thermophila intron. A 23-mer RNA was synthesized as a mixed ribo-deoxyribo oligonucleotide, modeling an expected base-paired region of P4 along with the J3/4 and P6 (5'-end bases of P6) regions. strand modeling the 3'-end bases of P6 and J6/7 regions, with which a triple helix may form, was synthesized as a pure oligoribonucleotide (7-mer RNA). The interactions of these oligonucleotides have been characterized by UV and circular dichroism (CD) spectroscopy. The results show that the 23-mer RNA forms a stable hairpin modeling the P4 base-paired region. Triple helix association between the 23-mer RNA hairpin and the 7-mer RNA single strand was detected by CD in the presence of Mg2+ (>5mM) but not in presence of a monovalent cation like Na+ (up to 500 mM). Studies on selected variants of both 7-mer and 23-mer RNAs were carried out. The results show that for the association of the two partner strands not only the formation of P6 helix but also triplet interactions between two strands are required. The association of the two strands in general follow a pattern predicted by comparative sequence analysis. Parallel studies on pure oligoribonucleotides having base sequence corresponding to those of the oligoribonucleotides showed no evidence of association under similar conditions, which could indicate that the 2'-hydroxyl groups of the riboses might play an important role in hydrogen bonding to form the required nucleoside triples. Molecular modeling studies on the proposed "plaited triple helix" formed by the association of the 23-mer RNA hairpin and 7-mer RNA single strand showed that the structure is sterically and energetically feasible.