Strabological results in patients with macular translocation surgery and counterrotation of the globe as a secondary procedure

Diplopia and strabismus following ocular surgeries

Postoperative diplopia and strabismus may result from a variety of ocular surgical procedures. Common underlying mechanisms include sensory disturbance, scarring, direct extraocular muscle injury, myotoxicity from injections of local anesthesia or antibiotics, and malpositioning of extraocular muscles by implant materials. The most common patterns are vertical and horizontal motility disturbance. Treatment options include prisms, botulinum, occlusion, or surgery.

Perception of tilt following counter-rotation surgery

BACKGROUND

Macular translocation surgery (MTS) is one of the treatment options for age-related macular degeneration (AMD) followed by counter-rotation surgery (CRS) to correct the resulting tilt. The objective of this paper is to determine the perception of tilt following CRS and identify factors that influence the perception of tilt in the presence of residual cyclorotation following CRS.

METHODS

Thirty-four AMD patients treated with MTS and CRS were investigated; and all measurements were made preoperatively, and after each surgical procedure. Fundus photographs were analysed with computer software to determine the degree of retinal rotation and reliability was assessed by two independent assessors. The degree of perceptual rotation was measured with Maddox rod and the subjective appreciation of tilt was established by direct questioning. Fixation preference was determined by cover test and convergence. Bagolini glasses were used to determine binocular outcome.

RESULTS

Post CRS, 20 of the 34 patients had adapted to tilt. There was a significant difference of 5 degrees +/- 7 degrees (95% confidence intervals: 1-8 degrees , t = 2.9, degree of freedom = 19, P = 0.008) between the degree of rotation measured from the fundus photographs and the Maddox rod measurement following CRS. Patients with residual retinal rotation less than or equal to 15 degrees did not appreciate tilt in free space. More importantly, fixation with the operated eye and ignoring the image from the non-operated eye was significantly associated with being free of tilt in natural viewing conditions (P < 0.05).

CONCLUSION

Despite the presence of residual cyclorotation of the macula following CRS of up to 27 degrees , a significant proportion (59%) of patients did not perceive the world as tilted in natural viewing conditions. Differences between retinal rotation and perceptual tilt provide evidence of sensory adaptation. It was patients who fixed with their operated eye and ignored the image from the non-operated eye who did not perceive tilt post CRS.

Results of compensatory extraocular muscle surgery after macular translocation

PURPOSE

Macular translocation is an optional surgical treatment for age-related macular degeneration. However, this technique induces postoperative torsional complaints and surgical counterrotation of the globe is mandatory. The purpose of this study is to report the effect of compensatory extraocular muscle surgery upon the torsional complaints in patients who underwent a macular translocation procedure.

DESIGN

The pre- and postoperative data on the first 35 patients in our department who underwent a counterrotation procedure after macular translocation surgery are reviewed.

METHODS

From November 2001 to January 2005, 35 patients underwent a macular translocation procedure, with subsequent extraocular muscle surgery to counterrotate the eye. Three types of rectus muscle transposition procedures were used: full-tendon transposition of two opposite rectus muscles, "crossed" half-tendon transposition of all rectus muscles ('split & cross' procedure), and "uncrossed" half-tendon transposition of all rectus muscles ('split & neighbor cross' procedure). In the majority of patients these procedures were associated with oblique muscle surgery.

RESULTS

With the selected procedures, retinal excyclodeviations are easier to correct then retinal incyclodeviations. In our hands, full-tendon transposition of two opposite rectus muscles with or without associated oblique muscle surgery, never corrects more than 30 degrees. 'Split & cross' procedures combined with oblique muscle surgery are sufficient for retinal excyclodeviations of 30-45 degrees and for incyclodeviations of up to 30 degrees; 'split & neighbor cross' procedures combined with oblique muscle surgery are sufficient for retinal excyclodeviations of 45-65 degrees and for incyclodeviations of up to 40 degrees .

CONCLUSIONS

The effect of the various procedures appears to be predictable. It is possible to select a surgical procedure as a function of the amount of retinal cyclodeviation.

Extraocular Muscle Surgery for Extorsion after Macular Translocation Surgery

PURPOSE

To report a new extraocular muscle surgery procedure for large-angle extorsion, and clinical management of subjective tilt and diplopia after full macular translocation (MT360).

DESIGN

Consecutive retrospective case series.

PARTICIPANTS

Seven patients with downward MT360 were evaluated after MT360, both before (preoperative) and after (postoperative) extraocular muscle surgery, with at least 6 months' follow-up.

METHODS

Information gathered included demographics, visual acuity, ocular motility, torsion by Maddox rod, ocular history, and symptoms of visual disturbance. Surgery on extraocular muscles was performed based on the magnitude of torsion measured after MT360 surgery.

MAIN OUTCOMES MEASURES

Maddox rod testing of torsion after MT360, and both preoperative and postoperative extraocular muscle surgery.

RESULTS

Mean preoperative torsion was reduced from 45.4+/-11.3 degrees to 8.3+/-4.8 degrees (at 6 months after MT360) (P = 0.03). Extraocular muscle surgery slightly reduced the mean hypertropia of the operated eye (preoperative, 20+/-10 prism diopters [PD], vs. postoperative, 11+/-6 PD) (P = 0.06). Mean exotropia was affected minimally by extraocular muscle surgery (preoperative, 22+/-31 PD, vs. postoperative, 20+/-24 PD). Three patients required a second extraocular muscle surgery (performed on the fellow eye) to correct residual extorsion and diplopia. Overall, 85% (6/7) of patients were free of both diplopia and tilt after 1 or 2 extraocular muscle surgeries.

CONCLUSIONS

Although our patients continued to have significant horizontal/vertical strabismus postoperatively, the extraocular muscle surgery performed was successful in reducing the torsional misalignment enough such that the remaining diplopia could be successfully ignored or suppressed.

Management of ocular torsion and diplopia after macular translocation for age-related macular degeneration: prospective clinical study

PURPOSE

To report the results of a prospective clinical series to evaluate the management of both torsion and diplopia in a large group of patients after full macular translocation (FMT) and extraocular muscle surgery.

DESIGN

Prospective interventional case series.

METHODS

Information gathered included demographic, visual acuity, ocular motility, torsion by Maddox rod, ocular history, and symptoms of visual disturbance. Surgery on two, three, or four extraocular muscles was performed based on the magnitude of torsion measured after FMT surgery.

RESULTS

Fifty-three patients were included for both objective and subjective outcomes and were evaluated after FMT, both before (preoperative) and after (postoperative) extraocular muscle surgery. Preoperative torsion for two- (n = 6), three- (n = 8), and four-muscle (n = 39) surgery groups was 21.2 +/- 4.6, 30.0 +/- 6.3, and 40.5 +/- 8.7 degrees, respectively. At 6 months, postoperative residual torsion was significantly reduced in each group (to 3.4 +/- 3.2, 5.6 +/- 5.5, and 4.5 +/- 6.8 degrees, respectively, for two-, three-, and four-muscle groups). Muscle surgery reduced mean hypertropia from 17 +/- 6 prism diopters preoperative to 4 +/- 10 prism diopters postoperative (P <.0001); mean exotropia was mildly reduced from 20 +/- 9 prism diopters preoperative to 13 +/- 11 prism diopters postoperative (P <.01). Subjective data regarding diplopia and tilted vision after FMT and muscle surgery were available on an additional 10 patients (n = 53 + 10 = 63). Overall, 41% (26/63) of these were free of both diplopia and tilt, whereas only 5% (3/63) had both symptoms constantly.

CONCLUSIONS

Extraocular muscle surgery is effective at relieving the variable amounts of torsion produced by FMT when graded to match preoperative torsion. The majority of patients were free of disabling tilt and diplopia after extraocular muscle surgery.