22 Diagnostic monocular occlusion in patients with binocular vision

To determine if angle of deviation changes significantly after diagnostic monocular occlusion (DMO) in patients with BSV (binocular single vision).We retrospectively analysed data from 136 patients with esotropia and 110 with exotropia, divided in BSV and non-BSV. Near and distance angles were measured over 3 visits and then after 2 hours monocular occlusion. Data were analysed with t-test and linear regression.Esotropes with BSV had significantly larger increases in deviation after DMO than non-BSV patients for near (5 PD vs 3 PD, 95%CI 3-7 PD, paired t-test p=0.0318) and for distance (6 PD vs 3 PD, 95%CI 4-8 PD, p=0.005). There was a significant correlation between the amount of change after occlusion and the initial angle for near (p=0.006) and for distance (p=0.010) in BSV patients only.In exotropes, there was no significant difference after DMO between BSV and non-BSV patients for near (p=0.09) and distance (p=0.532). There was a significant correlation between initial near angle of deviation and change in deviation after DMO in BSV patients(p=0.0009) but not in the non-BSV group (p=0.07). Distance angle of deviation before DMO was significantly correlated to the amount of change in deviation after DMO for both BSV (p=0.022) and non BSV patients (p=0.015).Our study shows that diagnostic monocular occlusion should be performed in all exotropes with initial angles of deviation of less than 30 PD. In esotropes, DMO is more likely to show significant increases in deviation in BSV patients, especially for smaller initial angles (less than 25 PD before DMO). These changes should be taken into account when planning surgery.

19 Unilateral lateral rectus resection as preferred procedure to treat patients with acquired distance esotropia

To report the results of a series of patients with acquired distance esotropia (ET) who underwent lateral rectus resection.We retrospectively analysed data from 21 symptomatic patients with acquired esotropia who did not tolerate prisms. Twelve patients had myopic esotropia, 5 patients decompensated esophoria and 4 patients age-related distance esotropia. Patients were divided in two groups; myopic and non myopic. Two patients in each group had undergone surgery to medial recti muscles previously. Near and distance angles were measured over 2 visits. Data were analysed with t-test (paired and unpaired).Average age was 47 (myopes), 77 (distance ET) and 26 years (esophoria). Mean spherical equivalent was -4.00 DS (myopes) and + 1 SD (non myopes). Lateral rectus resection ranged between 6 and 8 mm with an average of 7 mm in the myopic group and between 4 and 8 mm with an average of 6 mm in the non-myopic group.The distance angle was reduced from 19 PD to 6 PD in myopes (mean difference 12 PD, p<0.0001) and from 19 PD to 8 PD in non myopes (mean difference 12 PD, p=0.0011). There was no difference in reduction of distance angle between myopes and non-myopes (p=0.771). All patients had complete resolution of diplopia after surgery without needing prisms. Near angle was also fully corrected in 19 patients. One patient with myopia and one patient with distance esotropia went on to have medial rectus recession.Unilateral lateral rectus resection is an effective procedure for acquired distance esotropia in myopic and non-myopic patients.