[Esotropia and hyperopia corrected].

The subgroups of esotropia exist. The full optical correction of the hypermetropic refractive error is theoretically conclusive. The full correction further defined the diagnosis of three forms of esotropia. The earlier viewpoint that the full optical correction of the hypermetropia will decrease the accommodative normal demand or the accommodation is inactive and an exotropia will increase. After full correction of the hypermetropia the patients often complain about blurring of vision. Moreover, some doctors still have a confused ideas about full correction of the hyperopia. The final outcome that of most of patients with under-corrected hypermetropia, three commonly forms of esotropia (Accommodative esotropia, partially accommodative esotropia and nonaccommodative esotropia) will not be clearly differentiated as each requires different clinical management.

[The esotropia of the convergence-excess type subdivided into two forms].

There are two types of convergence excess esotropia in the classification of strabismus in our country. One is nonrefractive accommodative esotropia and another is nonaccommodative convergence excess esotropia. Inadequate heterophoria method to determine the AC/A ratio does not distinguish between a high AC/A ratio and nonaccommodative convergence excess. The diagnosis of nonrefractive accommodative esotropia is based on the presence of a high AC/A ratio as established with the gradient method to distinguish this condition from nonaccommative convergence excess.

[Pay attention to recovery of the binocular vision following strabismus surgery].

The primary goal of strabismus treatment is to correct and reverse a pathologic condition. Successful treatment is associated with relief from visual confusion or diplopia, a very high incidence of sensory binocular vision, an expanded peripheral visual field, and improved psychosocial function. Binocularity before and after strabismus surgery should be well understood. The stereopsis or sensory fusion should be examined routinely. The measurements should be repeated with the angle of strabismus neutralized with loose prisms. Eye misalignment is measured using the alternate prism and cover test, Eye alignment is measured using the simultaneous prism and cover test. The recent find is that the maximum horizontal deviation that will support true stereopsis is 4(Delta). The functional benefit can usually be obtained in the form of improved binocularity and, consequently, better stability of ocular alignment.

[Postoperative change of the Bielschowsky head tilt test in patients with unilateral congenital superior oblique palsy].

OBJECTIVE: To investigate the postoperative changes of the head tilt test in patients with unilateral congenial superior oblique palsy. METHODS: Thirty-eight cases with congenital unilateral superior oblique palsy underwent the ipsilateral inferior oblique or/and contralateral inferior rectus weakening procedure. Bielschowsky head tilt test was evaluated quantitatively before and after the operation by the prism cover test while the patient fixated at 33 cm and 6 m on the small light target. A positive Bielschowsky head tilt test was defined as one in which the vertical deviation when the head tilt to the side of the paresis was at least 5.0(Delta) greater than that on tilt to the uninvolved side. RESULTS: Before the operation, the hyperdeviation of the involved eye was 3.0(Delta) - 25.0(Delta) (average 11.0(Delta)) in primary position. The deviation on tilt to the side of the paresis was 23.0(Delta) (15.0(Delta) - 40.0(Delta)) and the deviation on tilt to the uninvolved side was 2.5(Delta) (0.0(Delta) - 10.0(Delta)). A positive Bielschowsky tilt test was found in all cases preoperatively. After the operation, the hyperdeviation of the involved eye was 0.0(Delta) - 5.0(Delta) (average 2.0(Delta)) in primary position. The result of Bielschowsky tilt test was still positive in 34 cases and negative in only 4 cases. CONCLUSION: In most cases with unilateral superior oblique paresis, the results of Bielschowsky tilt test do not change to negative postoperatively. The significance of using this test for evaluating surgical results remains to be determined.

A new method of extrapolating the sweep pattern visual evoked potential acuity.

PURPOSE: In order to compare the amplitude-spatial frequency (A-SP) regression method with amplitude-logVA (A-logVA) regression methods in extrapolating the sweep pattern visual evoked potential (SPVEP) acuity. METHODS: We measured SPVEPs in 21 children and three adults using sinusoidally-modulated horizontal gratings as stimuli. The responses were averaged and displayed through discrete Fourier transformations. SPVER acuity was then estimated by using both the SPVEP amplitude- spatial frequency function (A-SP function regression method) and the SPVEP amplitude-log visual-angle function (A-logVA function regression method). Furthermore, the Bailey Lovie logMAR chart was employed to define visual acuity. Curve estimates were calculated to derive a correlation index (R) for each method. RESULTS: There are significant differences (t = 2.71, P < 0.05) between the correlation indices of curves obtained using the A-logVA function (logarithmic model, 0.95 +/- 0.01) and that obtained by the A-SP function (inverse model, 0.92 +/- 0.02). The overall correlation coefficient (r) between logMAR acuity and acuity calculated by the A-logVA regression method was 0.32 (P < 0.05). The overall correlation coefficient (r) between logMAR acuity and acuity calculated by the A-SP regression method was 0.41 (P < 0.05). Paired t-tests show that SPVEP acuity from the A-logVA function was not significantly different from acuities of the logMAR function (t = 1.77, P = 0.09). The difference in their mean values is 0.14 +/- 0.08. However, SPVEP acuity calculated using the A-SP function regression method is significantly different from the acuity calculated from the logMAR function (t = 10.09, P < 0.01). The difference in their mean values is 0.41 +/- 0.04. CONCLUSIONS: The amplitude-logVA function regression method is more accurate in estimating SPVEP acuity in normal subjects with good visual acuity.