Extent of Improvement in Binocularity and Stereopsis in Constant Concomitant Horizontal Strabismus After Surgical Management and Its Association With the Postoperative Ocular Alignment

Abstract

BACKGROUNDThe gradual decrease in binocularity and stereopsis in patients with concomitant strabismus decreases the depth perception of the patients and adversely affects the reading speed and the motor dexterity skills of the individuals. It had been observed earlier that early management is necessary to help patients regain their binocularity, but recent studies indicate that binocularity and stereopsis may improve in these patients even if they are treated later in life, provided they are managed well. Hence, we undertook this study to determine the extent of improvement in binocularity and stereopsis in patients with long-standing large angle constant concomitant horizontal strabismus after surgical management after the age of 16 years and its association with the postoperative alignment. MATERIALS AND METHODSA prospective clinical trial was conducted in 30 patients with constant concomitant horizontal strabismus of more than 25 prism dioptres who presented after the age of 16 years. Binocularity and stereopsis were measured in the patients with the help of Worth 4-dot test, synoptophore, Lang II test plate, Randot test plates and TNO test plates. The measurements were done preoperatively and 6 weeks after surgical treatment. The changes in the measurements were associated with the postoperative alignment. RESULTSPreoperatively, the patients demonstrated either alternating or unilateral suppression with no measurable stereopsis. Postoperatively, satisfactory surgical alignment defined as tropia less than or equal to 8 Prism Dioptres (PD) was achieved in 23 (76.6%) of the patients. 19 (63.3%) patients achieved binocularity on Worth 4-dot test and synaptophore, but alternating or unilateral suppression was still present in 11 (36.6%) of the patients. 17 (56.6%) of the 30 patients achieved stereopsis on Lang II, Randot and TNO test plates. Development of stereopsis was associated with postoperative alignment with 16 (69.5%) of the 23 satisfactorily aligned patients and only 1 (14.3%) of the 7 patients with a residual deviation of ≥10PD achieving stereopsis. CONCLUSIONSignificant improvement in binocularity and stereopsis can be achieved in patients with long-standing large angle constant concomitant horizontal strabismus after surgical management even after the age of 16 years and the development of binocularity and stereopsis is associated with the final postoperative alignment. BACKGROUNDStrabismus or misalignment of the eyes is a common condition affecting 1-4% of the world population. 1 The presence of strabismus profoundly affects the life of the individual not only due to the cosmetic effect and the associated psychosocial implications, but also due to the decrease in binocularity, fusional amplitudes and stereopsis. It may also lead to a decrease in the visual acuity of an eye due to strabismic amblyopia, if strabismus develops during the early years of life. It has been seen that this decrease in Financial or Other, Competing Interest: None.

Sensory eye dominance following surgically correction for acute acquired concomitant esotropia of adulthood

“…29 Kohli et.al also pointed out that the development of binocularity and stereopsis is associated with the final postoperative alignment. 33 Here we showed that the sensory eye dominance after restoring ocular alignment was yet not balanced. Further research is required to clarify whether postoperative imbalanced eye dominance induce the problem of ocular alignment in long term.…”