An Update on Dragged-Fovea Diplopia Syndrome

Dragged-fovea diplopia syndrome (DFDS) is a type of binocular double vision caused by a displacement of the fovea in one or both eyes due to retinal disorders including epiretinal membranes or other maculopathies. DFDS induces diplopia through a mismatch between peripheral motor fusion and central (foveal) fusion. It can be diagnosed by utilizing the Lights on - Lights off test. While there is no cure, there are treatments for DFDS including monocular occlusion or blurring (tape, lenses, IOL), Bangerter filter, and Fresnel prisms. While this syndrome has been identified in the literature by multiple names including central-peripheral Rivalry (CPR)-type diplopia, macular diplopia, and foveal displacement syndrome, this article works to summarize the current known characteristics, diagnostic tests, and treatment for this syndrome.

Characteristics and type of strabismus associated to macular diplopia. Treatment outcomes

OBJECTIVE

To study the clinical characteristics of macular diplopia, treatment, and outcome.

METHODS

Retrospective descriptive study of cases referred to the ocular motility section of a tertiary hospital with diplopia, diagnosed with macular diplopia between 2022-23. The etiology of the macular pathology and the type of associated strabismus were recorded. The result was considered good if the diplopia improved or was eliminated with the medical or surgical treatment. Follow-up time from the onset of diplopia until data collection was recorded.

RESULTS

a total of 19 cases comprised the sample (63.2% women), mean age: 67.16 years. Amblyopia (21.1%), high myopia (47.4%), epirretinal membrane (ERM) (36.8%), neovascular membrane (26.3%), macular hole (10.5%), and lamellar (15.8%), and age macular degeneration (5.3%) were registered. The 47.4% had vertical diplopia, horizontal: 5.3 and 47.4% mixed. The mean horizontal deviation was: 7.3 PD (prism diopters) and vertical: 6.22 PD. Ocular extorsion was observed in 26.3%, and intorsion: 5.3%. Torticollis was present in 15.8%. The treatment consisted of strabismus surgery + Botox (15.8%), strabismus surgery (47.4%), medical treatment with Fresnel prims or Scotch cellophane (36.8%). A 68.4% presented a good result at the end of the study. The mean follow-up was 55.58 months.

CONCLUSIONS

Misregistration of macular photoreceptors is the most common cause of binocular diplopia in patients with ERM or other macular pathologies. Most complains of vertical or mixed diplopia. Sensorimotor evaluation of these patients should be thorough. Early diagnosis prevents unnecessary prescription of prism glasses. Surgical and/or medical treatment achieves good results in most cases.

Retinal misregistration and effect of surgery on its improvement in patients with epiretinal membrane

PURPOSE

To evaluate the prevalence of retinal misregistration, that is, misalignment of retinal elements that affect central and peripheral fusion, and the effect of surgery in patients with epiretinal membrane (ERM).

METHODS

This prospective interventional case-series was performed on 32 patients with symptomatic ERM with the complaint of binocular diplopia or decreased visual acuity. After the diagnosis of ERM, optotype frame, synoptophore, and lights on-off tests were used to evaluate retinal misregistration. Patients with severe symptoms underwent surgery and were followed for 3 months.

RESULTS

Of the 32 patients, 6 (19%) had preoperative diplopia. Optotype frame, synoptophore, and lights on-off tests had positive results in 20 (63%), 19 (63%), and 11 (34%) cases, respectively. Of the 6 diplopia cases, 5 showed positive results in all 3 tests and 1 was positive on optotype frame and synoptophore testing. Of the 26 cases without diplopia, 15 (58%) showed positive results in at least one test, including 6 (23%) in all three tests, 6 (23%) in two tests, and 3 (12%) in only one test. Ten patients underwent surgery. Postoperatively, all patients had negative lights on-off test, but optotype frame and synoptophore tests were negative in eight patients (80%). Two cases (20%) had postoperative diplopia, including 1 case with postoperative new-onset diplopia.

CONCLUSIONS

The prevalence of retinal misregistration was higher than the rate of diplopia. Surgery improved diplopia and results of tests of retinal misregistration.

[Disorders of the visual system following vitreoretinal and macular surgery]

The visual system is highly complex. Monocular or binocular disorders can develop, for example during tractive alterations of the macula, such as in epimacular membranes, and result in symptoms, such as double vision, aniseikonia or metamorphopsia. These symptoms are also observed following vitreomacular or vitreoretinal surgery, especially after treatment of large retinal detachment involving the macular area using pars plana vitrectomy or scleral buckle surgery but also as a result of vitreomacular interventions, such as membrane peeling in epimacular gliosis. Some patients have preoperatively existing latent conditions, which are not explicitly addressed during routine preoperative diagnostics. For patients and surgeons it is worth noting that these troublesome symptoms are often manifested in patients with good restoration of best corrected visual acuity following vitreomacular surgery. In such cases, patients tend to be dissatisfied with the surgical result despite good visual acuity. Treatment of postoperative metamorphopsia, aniseikonia and double vision is often difficult. In clinical studies, the maximum depth of tractive retinal folds has been described as a reliable morphological biomarker for the occurrence of metamorphopsia in epimacular gliosis. As metamorphopsia tends to postoperatively resolve slowly and even persist in ca. 30% of cases, this biomarker can have an impact on preoperative consulting and postoperative monitoring. Persistent binocular discomfort is often treatable by exact refraction correction and by applying a vertical and, if necessary, a horizontal prism. This often requires patience on the part of both the patient and the physician but is mostly successful due to fusion and adaptability.

Retinal displacement following pars plana vitrectomy with silicone oil tamponade for rhegmatogenous retinal detachment

PURPOSE

To evaluate the frequency of retinal displacement after pars plana vitrectomy (PPV) using silicone oil tamponade in patients with rhegmatogenous retinal detachment (RRD).

METHODS

Patients with fresh RRD were enrolled in this prospective interventional case series. A standard 3-port PPV with silicone oil tamponade was performed in all cases. A complete ocular examination, optical coherence tomography and fundus autofluorescence (FAF) imaging were performed at 1 and 3 months follow-up. Orthoptic examinations including synoptophore and light on-off tests were also performed at 3 months.

RESULTS

Twenty-three eyes from 23 patients with mean age of 56.6 ± 11 (range: 38-82) years were included. All patients were pseudophakic. Downward retinal displacement was found in 2 eyes (8.7%) showing hyperautofluorescent lines parallel to retinal vessels in FAF image. The patients with retinal displacement did not complain of metamorphopsia and did not show abnormality in orthoptic tests.

CONCLUSION

Unintentional retinal shift following PPV with silicone oil tamponade for RRD is uncommon and might have little clinical significance.