Clinical Investigation On The Stereopsis Of Myopic Anisometropia Patients Treated With Laser In Situ Keratomileusis

Objective With several methods, pre- and post-operative far and near stereopsis were tested in patients with myopic anisometropia undergone laser in situ keratomileusis (LASIK). So clinical effects of this treatment were evaluated at the highest level of vision function. The dominant eyes were also tested pre- and post-operatively, which would help to analyze the choice of dominant eyes in myopic anisometropia patients.Method 112 myopic anisometropia patients with spherical equivalent difference more than 1.50 D and cylinder equivalent difference more than 1.0 D were enrolled in the research. Before the operation, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refractive data, near stereopsis, crossed disparaty, uncrossed disparaty, far stereopsis and the scale, dominant eyes were examined. 3 months after anisometropia were abolished by LASIK, UCVA, refractive data, near stereopsis, crossed disparaty, uncrossed disparaty, far stereopsis and the scale, dominant eyes were examined again. Near stereopsis, crossed disparaty and uncrossed disparaty were measured by Yan's random-dot stereograms. Near stereopsis was also measured by Titmus stereograms and Jinguichang random-dot stereograms. Far stereopsis was measured by synoptophore. Dominant eyes were measured by hole-in-the-card test.Results 3 months after LASIK, UCVAs of 91.9% patients were the same as or better than those of preoperative. Postoperative spherical equivalent differences range from 0.00 D to 0.75 D and cylinder equivalent differences from 0.00 D to 0.50 D. Far and near stereopsis were improved obviously measured by all three methods. Near stereopsis tested by Yan's random-dot stereograms increased from 39 cases preoperatively to 83 cases postoperatively, by Jin's random-dot stereograms from 36 cases to 83 cases and by Titmus stereograms from 58 cases to 99 cases. Patients with normal crossed disparaty increased from 52 cases preoperatively to 95 postoperatively. Patients with normal uncrossed disparaty increased from 54 cases preoperatively to 95 postoperatively. Patients with normal far stereopsis increased from 46 cases to 83 cases and far fusion scaled improved obviously. There is significant difference in the improvement of stereopsis. The right eye was chosen as dominance in 75% cases, there is no relationship for the dominant eye with higher or lower myopic eye, or with better or worse UCVA eye. Dominant eyes hadn't changed till 3 months after the operation.Conclusion With the treatment of myopic anisometropia by LASIK, most patients got much improvement in far and near stereopsis. LASIK could rebuild, improve and promote the stereopsis, and treat the anisometropia effectively and safely. Most myopic anisometropia patients choose the right eye as their dominant eyes. There is no drift for dominant eyes after the LASIK.