A new method for quantification of metamorphopsia in patients with epiretinal membrane

Assessment of patient-reported outcomes in vitreomacular interface disorders: A systematic literature review

Patient-reported outcome measures (PROMs) assess the impact of disease on quality of life from the patient's perspective. Our purpose was to provide an overview of current PROMs used for vitreomacular interface disorders: macular hole, epiretinal membrane, and vitreomacular traction. We review the content coverage of all identified PROMs, assess them against quality-of-life issues as identified from earlier qualitative studies, and assess their psychometric quality (measurement properties). We identified 86 studies that used a PROM and 2 qualitative studies on quality of life of patients with a vitreomacular interface disorder. Current PROMs used in vitreomacular interface disorders have a limited content coverage and unknown psychometric quality. The National Eye Institute Visual Functioning Questionnaire was used most. None of the condition-specific PROMs used patient consultation during content development, and there is only a small overlap between the content of PROMs and quality-of-life issues in qualitative studies. Reporting of psychometric quality was sparse, and mostly limited to concurrent validity and responsiveness. There is a need for properly developed and validated PROMs in vitreomacular interface disorders.

Correlations among metamorphopsia test scores, optical coherence tomography findings and multifocal electroretinogram responses in epiretinal membrane patients

PURPOSE

To quantify metamorphopsia with a novel objective method in patients with epiretinal membrane (ERM) and to compare the relationships among metamorphopsia scores, spectral-domain optical coherence tomography (OCT) findings, and multifocal electroretinogram (mfERG) results.

METHODS

This study included 52 eyes of 52 patients with idiopathic ERM who underwent comprehensive ophthalmologic examinations, including measurement of best-corrected visual acuity (BCVA), OCT, and mfERG. The degree of metamorphopsia was quantified using MonPack One® (Metrovision, Perenchies, France). On the topographic map of the early treatment diabetic retinopathy (ETDRS) grid, retinal thickness in the central, superior, inferior, nasal, and temporal subfields were measured, and metamorphopsia scores for each corresponding subfield were also obtained. The amplitudes and implicit times of mERG were elicited from each subfield. Then, the correlations among metamorphopsia scores, OCT findings, and mfERG responses were analyzed.

RESULTS

The mean age of the patients was 65.3 ± 18.5 y, and the average metamorphopsia score of the individual subfields was 2.03 ± 1.18. Initial BCVA was 0.50 ± 0.12 logMAR, but there was no significant correlation between metamorphopsia scores and BCVA. The metamorphopsia scores from the central subfields showed significant correlations with central retinal thickness (CRT) (p = 0.001). The mean metamorphopsia scores in the central subfield showed a significant relationship with the mean N1 and P1 amplitudes (p = 0.001, p = 0.048, respectively), while no relationship was observed between metamorphopsia scores and mfERG amplitudes in other subfields.

CONCLUSIONS

The degree of metamorphopsia in patients with ERM could be objectively quantified in each subfield using a novel metamorphopsia test. The metamorphopsia scores were significantly correlated with retinal thickness, especially at the central subfields, and the scores in the central subfields were significantly correlated with the N1 and P1 amplitudes of mfERG. Thus, the metamorphopsia test can be a useful method to evaluate metamorphopsia symptoms for patients with ERM.

Validation of a novel functional test for assessing metamorphopsia using epiretinal membranes as a model

Current tests for assessing metamorphopsia do not account for confounders such as perceptual filling-in and spatial redundancy, which affect its sensitivity and repeatability. This proof-of-concept study aimed to assess the performance of a novel laboratory-based psychophysical test (Line Sag Test, LST) which addresses these issues for quantification of metamorphopsia in idiopathic epiretinal membranes. The LST quantifies perpendicular metamorphopsia at three eccentricities (3°, 6°, and 9°) along eight meridians (45° steps). Metamorphopsia was assessed using the LST and Amsler grid and the hit rates of both tests for detecting metamorphopsia were compared. Normal metamorphopsia scores using the LST did not differ significantly from 0 and fell within one step-size (p = 0.500). The LST detected significantly more cases of metamorphopsia than the Amsler grid (14/21 versus 3/21) (p = 0.003). Similarly, significantly more cases of visual distortions in asymptomatic iERMs were detected using the LST than the Amsler grid (11/18 versus 0/18) (p = 0.008). The LST has a higher hit rate compared to the Amsler grid (67% versus 14%). This work demonstrates a psychophysically-robust functional test addressing perceptual confounders is more sensitive for quantifying and localising metamorphopsia in macular disease, particularly in asymptomatic disease.

Detection of early visual impairment in patients with epiretinal membrane

PURPOSE

Patients with epiretinal membrane sometimes complain of impaired central visual function, despite good best corrected visual acuity (BCVA), as measured by visual acuity (VA) charts. Here, we evaluate early epiretinal membrane-induced changes in central VA.

METHODS

Subjects were 72 eyes of 36 patients with epiretinal membrane in only one eye and a BCVA in each eye better than 1.0, as measured by conventional Landolt C chart, at the Retina Division Clinic of the Department of Ophthalmology, Keio University Hospital, between December 2010 and November 2011. The conventional Landolt VA, functional VA (FVA) and contrast VA measurements were taken after a general eye examination. For the FVA, Landolt optotypes were sequentially displayed every 2 seconds, which size was changed according to the correctness of the answer. To exclude the influence of other diseases, a standard Schirmer test was performed to diagnose dry eye, and corneal and lens densities were evaluated.

RESULTS

Average BCVA measured by Landolt C chart was not changed between affected and unaffected fellow eyes. However, the affected eyes showed a poorer FVA score (0.21 ± 0.12, affected; 0.09 ± 0.12, fellow) and visual maintenance ratio (VMR) (0.90 ± 0.04, affected; 0.94 ± 0.04, fellow), measured by the FVA system, and contrast VA score (0.35 ± 0.11, affected; 0.25 ± 0.14, fellow) than fellow eyes. The FVA and contrast VA values were correlated with the presence of epiretinal membrane, but not with the presence of dry eye, cataract and corneal densities.

CONCLUSION

FVA and contrast VA results reflected early changes in central visual function caused by epiretinal membrane, which were not detected by conventional Landolt BCVA.

Pattern VEPs before and after idiopathic epiretinal membrane removal

Pattern visual evoked potentials (pVEPs) were used to assess the visual function before, and 1 and 6 months after removal of an idiopathic epiretinal membrane (ERM) from eight eyes. All patients underwent a standard three-port pars plana vitrectomy to remove the ERM removal and cataract surgery. pVEPs were elicited by check sizes of 15', 30', 60', and 120' with a reversal rate of 2 reversals/s. One hundred responses were averaged with an analysis time of 300 ms. The amplitude ratio (affected eye/fellow eye) of the P100 component were significantly larger at 6 months with smaller check sizes, and the increase was accompanied by an improvement of the VA. The mean peak latency of P100 did not change significantly for all check sizes. We conclude that the improvement of the P100 amplitude with smaller check sizes resulted from the recovery of visual function after the ERM removal.

Quantification of metamorphopsia in patients with epiretinal membranes before and after surgery

BACKGROUND

To evaluate quantification of metamorphopsia before and after the removal of unilateral epiretinal membrane (ERM).

METHODS

One hundred and four consecutive patients with unilateral ERM scheduled for membrane peeling were prospectively enrolled. A complete ophthalmologic examination was performed. Metamorphopsia was evaluated, with standard Amsler grids and a laser grid generated with a scanning laser ophthalmoscope (SLO). The SLO procedure determined the area of distortion and was performed twice at a 30-minute interval to evaluate its reproducibility. The result was considered to be reliable when the area of distortion was identical in both SLO test sessions. One year after surgery, a complete ophthalmologic examination was performed. Metamorphopsia was again quantified with the SLO procedure.

RESULTS

Before surgery, a reliable quantification of metamorphopsia (defined as area of distortion) could be performed in 98 patients (94%). Among these patients, 85 completed the follow-up of 12 months after surgery. Of these 85 patients, visual distortions had been detected preoperatively in 48 patients (56%). One year after surgery, visual distortions were detected in only 11 patients (13%). In 48 patients with preoperative distortions, the decrease of the area of distortion correlated with the change in visual acuity (r = -0.460, p = 0.011).

CONCLUSIONS

SLO-based evaluation of metamorphopsia made it possible to provide a fast and reliable method for preoperative and post-operative quantification of visual distortion in patients undergoing ERM removal.

Assessment of macular function by multifocal electroretinogram before and after epimacular membrane surgery

PURPOSE

To evaluate macular function before and after successful surgical peeling of idiopathic epimacular membranes by means of multifocal electroretinogram (ERG) and measuring the first order Kernel.

METHODS

Multifocal ERG of 10 patients (10 eyes) with idiopathic epimacular membrane were recorded before and after successful macular peeling. The retinal response densities of areas 1 and 2 were compared pre- and postoperatively and the functional state of the retina beneath the epimacular membrane was evaluated. The postoperative period was 3-6 months.

RESULTS

Preoperatively, the electrical retinal response densities in the foveal and the perifoveal area were apparently decreased. After a mean postoperative period of 3 months the electrical response densities of the above areas improved. This improvement continued 6 months after the operation.

CONCLUSION

In idiopathic epimacular membranes, the decrease in retinal electrophysiologic response was not limited to the fovea but also involved the perifoveal area. The electrical retinal response density of these areas gradually improved after peeling of the epimacular membrane.