Abstract
Purpose: :
To assess the difference in the amount of counter–rotation achieved by operating on four extra ocular muscles compared with two extra ocular muscles following macular translocation for age related macular degeneration. To examine whether there is any difference in subjective and objective measurements of tilt and to assess post operative motility.
Methods: :
20 patients were included; all of the patients had their macula translocated superiorly. In order to counter–rotate the tilted image, ten patients had both oblique muscles relocated and ten patients had both oblique muscles and both horizontal recti relocated. Subjective monocular tilt was measured using the Maddox rod. Objective monocular tilt was measured using fundus photography. Motility was assessed using the limbus test of motility of Kestenbaum. Tilt was measured before macular translocation, after macular translocation before muscle surgery and following muscle surgery.
Results: :
Four muscle surgery produced a mean of 41.5±SD 10 (range 25 to 50) degrees of counter rotation measured using Maddox Rod and 43.6±SD 7.6 (range 31 to 47) degrees of counter rotation using fundus photography. Two muscle surgery produced a mean of 32.5±SD 14.6 (range 10 to 45) degrees of counter rotation measured using Maddox Rod and 38.9±SD 14 (range 22 to 63) degrees of counter rotation using fundus photography. The difference between the two groups was tested using student’s t – test assuming unequal variance. The difference was not significant at p=0.12. The final post operative subjective and objective angles of tilt were compared and showed an average difference of 7.9±SD 5.3 (range 2 to 18) degrees. This suggests that the patient appreciated less tilt subjectively than was measured by the fundus photography. This fact may represent a form of sensory adaptation. Both groups of patients have some limitations in eye movements following counter–rotation muscle surgery. Most patients demonstrated a V or Sigmoid pattern. Neither the amount of limitation of eye movements nor the pattern was significantly different between the 2 groups.
Conclusions: :
Four muscle surgery produces more counter rotation than two muscle surgery without any significant difference in motility.
Keywords: age-related macular degeneration