Retinally Induced Aniseikonia: A Case Series

Aniseikonia after reduced-fluence photodynamic therapy in patients with central serous chorioretinopathy

This study investigated aniseikonia after reduced-fluence photodynamic therapy (RFPDT) for central serous chorioretinopathy (CSC). We examined 48 eyes of 48 patients (38 men; mean age, 49.2 ± 9.9 years) with CSC resolved after RFPDT. Horizontal and vertical aniseikonia were measured using the New Aniseikonia Test at baseline, 6 months, and 12 months after RFPDT. The maximum absolute value of the horizontal and vertical measurements indicated the aniseikonia score. The aniseikonia score was 2.2 ± 2.3 at 6 months and 2.2 ± 2.0 at 12 months after RFPDT, both of which improved significantly from the baseline score of 4.1 ± 2.9 (P < 0.05 and P < 0.01, respectively). The 12-month aniseikonia score significantly correlated with the baseline aniseikonia score (P = 0.047), outer nuclear thickness at baseline (P = 0.027) and 12 months after RFPDT (P = 0.014), baseline SRD area (P = 0.005), and ellipsoid zone disruption at 12 months after RFPDT (P = 0.021). In multivariate analysis, baseline serous retinal detachment (SRD) area (P = 0.034) was significantly associated with aniseikonia score at 12 months after RFPDT. Eyes with a larger SRD area might have higher aniseikonia scores even after SRD resolution following RFPDT.

Clinic study on macular epiretinal membrane in patients under the age of 40 years

BACKGROUND

To describe the risk factors and clinical characteristics of macular epiretinal membrane (MEM) disease in patients up to the age of 40 years and to evaluate the therapeutic effect of IVTA on MEM.

METHODS

Clinical records were reviewed and the etiology of each case and the age distribution data were collected in this retrospective, cohort study. The clinical characteristics of MEM and the factors affecting VA were analyzed. Additionally, we contrasted the effects of MEM peeling with and without intravitreal triamcinolone acetonide on visual acuity (VA) and central foveal thickness (CFT).

RESULTS

In young patients, the incidence of partial posterior vitreous detachment (P-PVD) was considerably higher in IMEM than SMEM (P = 0.007). Furthermore, patients with stage 3 MEM had lower BCVA values than patients with stage 4 MEM (P < 0.001). Patients who live in urban had lower BCVA values than patients in rural (P < 0.001). Patients with IS/OS integrity had lower BCVA values than patients without IS/OS integrity (P < 0.001). The BCVA values in patients with IMEM were significantly lower than those of patients with SMEM (P < 0.001). BCVA was associated most commonly with etiology (P = 0.001), followed by region (P = 0.002). All patients had a decrease in logMAR Vas and CFT, but the combination of intraoperative IVTA resulted in a more significant decrease in logMAR Vas (P = 0.007) and CFT (P = 0.046).

CONCLUSION

In young patients, the incidence of P-PVD was significantly higher in IMEM cases than in SMEM cases. The region, MEM stage, IS/OS integrity, and etiology influenced VA. Etiology was associated most commonly with BCVA. In individuals under 40, the combination of intraoperative IVTA resulted in a more significant decrease in logMAR Vas and CFT.

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.

Long-term functional outcomes and vision-related quality of life after vitrectomy for epiretinal membrane: a prospective cohort study

To investigate the long-term effect of unilateral idiopathic epiretinal membrane (uiERM) removal on monocular and binocular visual function, and on vision-related quality of life (VR-QoL). Prospective, single-center study. The following data were collected before and after surgery: distance monocular and binocular best-corrected visual acuity (BCVA), horizontal and vertical metamorphopsia, horizontal and vertical aniseikonia, stereoacuity and National Eye Institute Visual Function Questionnaire-25 item (NEI VFQ-25). Forty-two patients (mean age: 72.7 ± 7.4 years; 24 men) were included. At 6 months postoperatively, distance monocular BCVA (p < 0.001), horizontal metamorphopsia (p = 0.001) and the composite score of NEI VFQ-25 (p < 0.001) significantly improved, in comparison to baseline. At 2 years postoperatively, distance monocular (p < 0.001) and binocular (p = 0.01) BCVA, horizontal (p < 0.001) and vertical (p = 0.02) metamorphopsia, vertical aniseikonia (p = 0.01), stereoacuity (p < 0.001) and 3 subscales scores of the NEI VFQ-25 (p < 0.05) (“general vision”, “mental health”, “driving”) significantly improved in comparison to baseline. Removal of uiERM improves VR-QoL and achieves good visual outcomes on both monocular and binocular visual parameters over long-term. Visual symptoms induced by macular contraction have different improvement kinetics after surgery. Stereopsis, the highest level of binocular vision, can be improved in some cases.

Visual functions affecting stereopsis in patients with branch retinal vein occlusion

PURPOSE

To quantify stereopsis and other visual functions in patients with unilateral branch retinal vein occlusion (BRVO) and to investigate vision-related parameters that affect stereopsis.

DESIGN

Prospective observational study.

SUBJECTS

Forty-five patients undergoing intravitreal ranibizumab (IVR) treatment for unilateral BRVO.

METHODS

We examined stereopsis using the Titmus stereo test (TST) and TNO stereotest (TNO), best corrected visual acuity (BCVA), letter contrast sensitivity, severity of metamorphopsia and degree of aniseikonia before and 6 months after IVR.

MAIN OUTCOME MEASURES

Visual functions that affect stereopsis.

RESULTS

Baseline stereopsis in patients with BRVO was 2.7 ± 0.6 (range, 1.6-3.5) in the TST and 2.8 ± 0.5 (range, 1.8-3.3) in TNO. TST and TNO scores were significantly correlated with BCVA and letter contrast sensitivity at baseline (P < 0.001) but not with other visual functions. IVR treatment significantly improved stereopsis, BCVA, and letter contrast sensitivity. After treatment, TST scores were significantly correlated with BCVA (P < 0.001), letter contrast sensitivity (P < 0.001), and aniseikonia (P < 0.01). TNO scores were significantly correlated with BCVA (P < 0.01) and letter contrast sensitivity (P < 0.01). TST and TNO scores after treatment were significantly correlated with BCVA at baseline (P < 0.01 for both).

CONCLUSIONS

Deterioration of stereopsis in patients with BRVO was associated with changes in visual acuity and contrast sensitivity after treatment. Initial visual acuity is a prognostic factor for posttreatment stereopsis.

CORRELATION BETWEEN MACULAR MICROSTRUCTURES AND ANISEIKONIA AFTER IDIOPATHIC EPIRETINAL MEMBRANE REMOVAL

PURPOSE

To analyze the correlation between preoperative measurements of macular microstructures and aniseikonia after epiretinal membrane removal.

METHODS

This retrospective study included 32 eyes of 32 patients who underwent epiretinal membrane surgery and were followed up for 12 months. Spectral-domain optical coherence tomography was used to measure the thicknesses of the ganglion cell layer-inner plexiform layer, inner nuclear layer (INL), and outer retinal layer in macular microstructures. The new aniseikonia test was used to measure vertical and horizontal aniseikonia scores.

RESULTS

There was a significant decrease in central macular thickness and ganglion cell layer-inner plexiform layer thickness at 6 and 12 months postoperatively (all P < 0.001). Vertical aniseikonia scores, horizontal aniseikonia scores, and INL and outer retinal layer thicknesses did not show significant changes. Vertical aniseikonia scores and horizontal aniseikonia scores were significantly associated with INL thicknesses of each meridian at each follow-up time point (all P < 0.05). Preoperative vertical and horizontal INL thicknesses were correlated with vertical aniseikonia scores and horizontal aniseikonia scores at 12 months postoperatively (P = 0.014 and P = 0.002, respectively).

CONCLUSION

Aniseikonia values did not change after epiretinal membrane removal and were associated with INL thickness before and after surgery. Thus, preoperative INL thickness could be used as a predictor of surgical prognosis in epiretinal membrane patients.

Field-wide Quantification of Aniseikonia Using Dichoptic Localization

SIGNIFICANCE

We validated a novel paradigm to measure aniseikonia across the visual field and used a mathematical approach that is able to describe the magnitude and shape of aniseikonia in a concise, clinically meaningful fashion.

PURPOSE

The measurement of aniseikonia has been performed clinically for more than half a century; however, amalgamation of field-wide local variations in binocular spatial localization into clinically applicable global metrics has yet to be attempted. Thus, the goal of the current study was twofold: first, to measure field-wide aniseikonia and second, to compare how local and global metrics each capture optically induced aniseikonia.

METHODS

Twelve visually normal observers performed a dichoptic localization task at 24 locations in the visual field. This was done in four conditions: (A) while wearing red-green filters, (B) while wearing green-red filters, (C) while wearing a monocular 5% overall size lens, and (D) while wearing a monocular 6% meridional size lens. The physical settings at perceptual equality were then used to compute both local (relative magnification) and global (coefficients for Zernike terms) descriptors of aniseikonia.

RESULTS

The comparison of each lens condition to the baseline condition confirmed predicted shifts in both the sign and magnitude of aniseikonia at both the local and global levels; however, the intraobserver levels of precision were moderate, and systematic underestimations were present across all locations in conditions C and D.

CONCLUSIONS

Local and global analyses derived from dichoptic localization data were both able to capture optically induced changes in binocular spatial perception; however, solutions that address the diagnostic and therapeutic challenges associated with this paradigm are needed before clinical implementation can proceed.

Treatment for Central-Peripheral Rivalry-Type Diplopia ("Dragged-Fovea Diplopia Syndrome")

PURPOSE

To report the effectiveness of treatments for central-peripheral rivalry (CPR)-type diplopia due to retinal misregistration.

DESIGN

Retrospective, interventional case series.

METHODS

Fifty adults with retinal misregistration and CPR-type diplopia (minimum frequency of "sometimes" at distance and/or for reading) caused by epiretinal membrane (n = 44) or other retinal disorders (n = 6) were enrolled in this study, conducted at adult strabismus clinics, Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, a tertiary medical center. Treatments included Bangerter filter, adhesive tape, Fresnel prism, clear prism (incorporated into glasses or loose prism in the office), iseikonic manipulation (using iseikonic lenses or contact lenses), a MIN lens, or epiretinal membrane (ERM) peeling (alone or in any combination). Not all patients underwent all of these treatments.

RESULTS

Main outcome measurements were diplopia frequency, evaluated using the Diplopia Questionnaire. Success was defined as "never" or "rarely" diplopic for distance and reading, using the Diplopia Questionnaire, at an outcome examination as close as possible to 6 months. Overall, 17 of 50 patients (34%; 95% confidence interval [CI], 21%-49%) were classified as successful. Fresnel prism was successful in 4 of 7 patients (57%; 95% CI, 18%-90%); Bangerter filter in 4 of 28 patients (14%; 95% CI, 4%-33%); ERM peeling in 8 of 18 patients (44%; 95% CI, 22%-69%); and iseikonic manipulation in 1 of 23 patients (using a contact lens; 4%; 95% CI, 0%-22%).

CONCLUSIONS

CPR-type diplopia may be relieved in some patients using nonsurgical treatment options consisting of Fresnel prism or Bangerter filter. ERM peeling was surprisingly successful and should be considered.

Prevalence and Associations of Central-Peripheral Rivalry-Type Diplopia in Patients With Epiretinal Membrane

Importance

The prevalence and clinical associations of patients with epiretinal membrane (ERM) who develop central-peripheral rivalry (CPR)–type diplopia are unknown.

Objectives

To determine the prevalence of CPR-type diplopia in retinal disease clinic patients with ERM and to determine clinical findings associated with CPR-type diplopia.

Design, Setting and Participants

A prospective cross-sectional study of 31 patients with ERM from retinal disease clinics to determine the prevalence of CPR-type diplopia. A retrospective case cohort of 25 additional patients with ERM, selected from adult strabismus clinics, was added (total = 56) to determine clinical associations with CPR-type diplopia. All data were collected between June 2014 and November 2016; prospective cohort data were collected from June 2016 to November 2016.

Main Outcomes and Measures

The presence of diplopia was determined by patient history and diplopia questionnaire responses. Visual acuity and ocular alignment were recorded. Metamorphopsia was documented qualitatively by evaluation of the door frame and Amsler grid and measured quantitatively using M-charts and D-charts. Aniseikonia was determined by subjective description and results of the Awaya new aniseikonia test. Retinal misregistration testing consisted of optotype-frame test and synoptophore; CPR-type diplopia was defined as diplopia associated with evidence of retinal misregistration when other causes did not fully explain diplopia. Outcomes were as follows: prevalence of CPR-type diplopia in patients with ERM seen in retinal disease clinics, and whether or not clinical findings differed between patients with ERM and CPR-type diplopia vs patients with ERM without CPR-type diplopia.

Results

Of the 31 patients with ERM seen in retinal disease clinics, 16 were women and 15 were men; the mean (SD) age was 69 (10) years. The prevalence of any diplopia was 23% (7 of 31; 95% CI, 10% to 41%), with CPR-type diplopia present in 16% (5 of 31; 95% CI, 5% to 34%). For analysis of associations, 12 of 56 patients (21%) had CPR-type diplopia and 37 (66%) had no diplopia. Seven of the 56 patients were excluded for other types of diplopia. Patients with CPR-type diplopia had better worse-eye visual acuity (mean difference, −0.23; 95% CI, −0.37 to −0.09 logMAR, P = .003), and more severe quantitative metamorphopsia (mean M-score difference 0.6; 95% CI, 0.05 to 1.1, P = .01) than patients without diplopia, but similar aniseikonia (Awaya new aniseikonia test; mean difference 0.6%; 95% CI, −2.9% to 4.0%, P = .33) and similar evidence of retinal misregistration (100% vs 73%; P = .09) by any test.

Conclusions and Relevance

Our findings suggest that CPR-type diplopia is not uncommon in patients with ERM. On average, patients with CPR-type diplopia have better visual acuity and more metamorphopsia than those without CPR-type diplopia, but there is considerable individual variability. Aniseikonia and retinal misregistration are similar between patients with ERM associated with CPR-type diplopia and those without CPR-type diplopia. Retinal misregistration with coexistent metamorphopsia appears necessary but is not sufficient for CPR-type diplopia.

Aniseikonia and anisometropia: implications for suppression and amblyopia

Aniseikonia is a difference in the perceived size or shape of images between eyes, and can arise from a variety of physiological, neurological, retinal, and optical causes. Aniseikonia is associated with anisometropia, as both anisometropia itself and the optical correction for anisometropia can cause aniseikonia. Image size differences above one to three per cent can be clinically symptomatic. Common symptoms include asthenopia, headache and diplopia in vertical gaze. Size differences of three and more impair binocular visual functions such as binocular summation and stereopsis. Above five per cent of aniseikonia, binocular inhibition or suppression tend to occur to prevent diplopia and confusion. Aniseikonia can be measured using a range of techniques and can be corrected or reduced by prescribing contact lenses or specially designed spectacle lenses. Subjective testing of aniseikonia is the only way to accurately measure the overall perceived amount of aniseikonia. However, currently it is not routinely assessed in most clinical settings. At least two-thirds of patients with amblyopia have anisometropia, thus we may expect aniseikonia to be common in patients with anisometropic amblyopia. However, aniseikonia may not be experienced by the patient under normal binocular viewing conditions if the image from the amblyopic eye is of poor quality or is too strongly suppressed for image size differences to be recognised. This lack of binocular simultaneous perception in amblyopia may also prevent the measurement of aniseikonia, as most common techniques require direct comparisons of images seen by each eye. Current guidelines for the treatment of amblyopia advocate full correction of anisometropia to equalise image clarity, but do not address aniseikonia. Significant image size differences between eyes may lead to suppression and abnormal binocular adaptations. It is possible that correcting anisometropia and aniseikonia simultaneously, particularly at the initial diagnosis of anisometropia, would reduce the need to develop suppression and improve treatment outcomes for anisometropic amblyopia.

Associations of aniseikonia with metamorphopsia and retinal displacements after epiretinal membrane surgery

PurposeTo determine the correlation of the degree of aniseikonia with the retinal displacements and metamorphopsia in patients that have undergone successful epiretinal membrane (ERM) surgery.MethodsSubjects were 28 eyes with an ERM in 28 patients. The New Aniseikonia Test (NAT) and M-CHARTS were used to quantify the degree of preoperative and postoperative aniseikonia and metamorphopsia. We also evaluated the distance between the intersections of 2 sets of retinal vessels situated vertically or horizontally by using spectral-domain optical coherence tomography (SD-OCT) images in 28 patients.ResultsThe vertical score of M-CHARTS (MV) was not significantly improved, but the horizontal score of M-CHARTS (MH) was significantly improved at 1 week, 1 month, and 3 months postoperatively. The preoperative NAT score was significantly correlated with the preoperative MH. The NAT score at 3 months was significantly correlated with the MH at 3 months and the MV at 3 months. The preoperative NAT score was significantly correlated with the ratio of the vertical retinal displacement at 1 month and at 3 months after surgery. However, the NAT scores did not improve significantly at any postoperative times.ConclusionsThe degree of aniseikonia was significantly correlated with the degree of metamorphopsia and the tangential displacement of the retina after ERM surgery. Aniseikonia is difficult to improve and metamorphopsia may be a more sensitive parameter to detect the functional recovery after successful ERM surgery.

Causes of Diplopia in Patients With Epiretinal Membranes

PURPOSE

To describe the causes of diplopia in patients with an epiretinal membrane (ERM) and presenting diplopia.

DESIGN

Retrospective observational case series.

METHODS

We reviewed patients diagnosed with an ERM, who had been seen by both retinal and strabismus specialists in a tertiary medical center. Data recorded: orthoptic evaluation, retinal misregistration (optotype-frame test, and synoptophore central peripheral superimposition slides at 5 and 10 degrees), and cause of any diplopia (retinal misregistration vs strabismus vs optical/refractive error). We defined central-peripheral rivalry-type diplopia as presenting symptomatic diplopia with evidence of retinal misregistration, and where other causes did not fully explain diplopia. The frequency of each cause of diplopia in patients with ERM was determined.

RESULTS

Of 50 patients with ERM, 25 had symptomatic diplopia and 25 had no diplopia. Eleven of 25 diplopic patients (44%) had retinal misregistration as the sole cause (central-peripheral rivalry-type diplopia), 7 (28%) strabismus (1 of 7 initally appeared to have central-peripheral rivalry-type diplopia), 1 (4%) optical/refractive error (monocular diplopia), 2 (8%) mixed retinal misregistration (central-peripheral rivalry-type diplopia) and strabismus, and for 4 (16%) diplopia cause was indeterminate. Unexpectedly, 15 of 25 patients without diplopia (60%) had evidence of retinal misregistration.

CONCLUSIONS

Patients with ERM and presenting diplopia may have 1 of several causes of diplopia, most commonly retinal misregistration (central-peripheral rivalry-type diplopia). Nevertheless, diplopic patients with retinal misregistration may also have treatable strabismus or optical/refractive error as the primary barrier to single vision and therefore many potential barriers to single vision should be considered.

Aniseikonia following pneumatic retinopexy for rhegmatogenous retinal detachment

PURPOSE

To evaluate the characteristics of aniseikonia in patients with rhegmatogenous retinal detachment (RD) after pneumatic retinopexy.

DESIGN

Prospective, interventional case series study.

METHODS

Thirty patients who had undergone pneumatic retinopexy as the initial procedure for rhegmatogenous retinal detachment were selected for this study. The principal outcomes included visual acuity, postoperative aniseikonia measured by the New Aniseikonia Test, anatomical success, and measurement of central retinal thickness using optical coherence topography (OCT). These outcomes were measured postoperatively at 3, 6, and 12 months.

RESULTS

The median patient age was 37 years (range, 13-57 years), with 17 cases of macula-off RD and 13 cases of macula-on RD. All of these patients achieved anatomical success, proven by OCT after surgical repair. Three months after pneumatic retinopexy, 18 patients (60.0%) developed micropsic aniseikonia and aniseikonia was diagnosed in 15 patients (88.2%) in the macula-off RD group, leaving 2 patients (11.8%) unaffected. In the macula-on RD group, 3 patients (23.1%) were found to have aniseikonia, while 10 patients (76.9%) were unaffected. The presence of aniseikonia was strongly linked to the difference in central retinal thickness, between the operated eye and the fellow eye, measured at 12 months postoperatively.

CONCLUSION

Aniseikonia after pneumatic retinopexy for rhegmatogenous RD may be related to the preoperative macular status. Macula-off RD patients had a higher incidence of aniseikonia, compared to macula-on RD patients, following retina reattachment. There was a moderate to high correlation between the grading of aniseikonia and the difference in central retinal thickness.