The multifocal electroretinogram in central serous chorioretinopathy

Visual function during and after an acute central serous chorioretinopathy episode

PURPOSE

To evaluate visual function parameters during and after an acute central serous chorioretinopathy (CSC) episode.

METHODS

A prospective study included 19 fovea involving acute CSC patients with episode resolution within 3 months from the episode onset. Optical coherence tomography, best corrected visual acuity (BCVA), contrast sensitivity (CS), microperimetry (MP), and multifocal electroretinography (mfERG) were performed at baseline, 3 and 6 months from the episode onset. In a sub analysis, patients were divided into groups with greater (gMV, N = 9) and lower (lMV, N = 10) macular volume at presentation, and functional outcomes were observed.

RESULTS

BCVA (p < 0.001), average CS (CS-A) (p < 0.001), average retinal sensitivity (MP-A) (p < 0.001), mfERG amplitude densities in the first and second ring (mfERG-A1, p < 0.001; mfERG-A2, p = 0.017), and implicit times in the first, second, and third ring (mfERG-IT1, p = 0.024; mfERG-IT2, p = 0.002; mfERG-IT3, p = 0.018) improved with episode resolution 3 months after the episode onset. From 3 to 6 months after the episode onset, only CS-A (p = 0.045) continued to improve. Patients in the gMV group had lower mfERG-A1 (p = 0.017) and central retinal sensitivity (MP-C, p = 0.05) 6 months from the episode onset.

CONCLUSIONS

Although all functional parameters mostly improve with CSC episode resolution, only CS continues to improve thereafter. Patients with greater MV at presentation have worse functional outcomes. Visual function impairment in acute CSC patients is confined to the topographical area of subretinal fluid detachment.

Pattern electroretinography in patients with unilateral acute central serous chorioretinopathy

BACKGROUND

To evaluate the pattern electroretinography (PERG) in patients with acute central serous chorioretinopathy (CSCR) at baseline and after spontaneous resolution.

METHODS

A total of 32 patients (mean ± SD age: 38.8 ± 8.2 years, 71.9 per cent female) with unilateral acute CSCR and spontaneous resolution during follow-up period were included. The unaffected eyes of the study patients comprised the control group. The best-corrected visual acuity, PERG and optical coherence tomography findings were recorded both at baseline and following spontaneous resolution at two to four months.

RESULTS

The P50 and N95 amplitudes of the affected eyes were significantly lower than the control group both at baseline and after CSCR resolution (p < 0.001 for each). A significant increase was noted in both P50 and N95 amplitudes of the affected eyes from baseline to post-resolution (p < 0.001 for each). Subfoveal choroidal thickness was significantly higher in the affected eyes as compared with control eyes both at the baseline and after CSCR resolution along with a significant decrease in the affected eyes from baseline to post-resolution (p < 0.001 for each). The central retinal thickness was higher in the affected eyes as compared with the control eyes at baseline (p = 0.009), along with a significant decrease in the affected eyes from baseline to post-resolution (p < 0.001). Between the baseline P50 amplitude and the visual acuities of the affected eyes, a strong correlation was noted at baseline (r = -0.691, p < 0.001) and a moderate correlation was noted after CSCR resolution (r = -0.422, p = 0.031).

CONCLUSIONS

In conclusion, our findings revealed an association of CSCR with impaired P50 and N95 amplitudes and a significant improvement but not a complete recovery in both parameters after CSCR resolution. Our findings emphasise potential utility of PERG in the electrophysiological evaluation of functional impairment in CSCR patients and the likelihood of P50 amplitude to have a prognostic value in CSCR.

Electroretinographic findings in transplant chorioretinopathy

Aim:

Transplant chorioretinopathy is a rare complication following solid organ or bone marrow transplantation and can result in severe vision loss. This series presents electroretinogram (ERG) results in patients with this condition.

Methods:

Patients who presented with bilateral vision loss following bone marrow or solid organ transplantation were identified. A complete ophthalmologic examination, fundus photography, and fluorescein angiography (FA) were performed. Full-field ERG was obtained in all patients and a multifocal ERG (mfERG) was obtained in two patients.

Results:

Four patients were identified. All patients had bilateral vision loss and displayed a characteristic pattern of mottled hyperfluorescence on FA. Three patients developed progressive vision loss ranging from 20/60 to hand motions whereas one retained 20/40 vision. All patients exhibited moderate to severe cone dysfunction, while the degree of rod abnormalities was varied. Two patients with severe cone dysfunction showed mild clinical changes initially, but later developed progressive vision loss and chorioretinal atrophy.

Conclusion:

Transplant chorioretinopathy patients undergoing ERG testing show cone dysfunction with a variable degree of rod dysfunction. ERG abnormalities preceded the visual acuity and clinical changes in two patients, suggesting that ERG may be a helpful predictor of the clinical course in this rare disease.

Correlation between functional and anatomical assessments by multifocal electroretinography and optical coherence tomography in central serous chorioretinopathy

To evaluate the correlation between functional and anatomical assessments with multifocal electroretinography (mfERG) and optical coherence tomography (OCT) in patients with acute central serous chorioretinopathy (CSC). Thirty-four eyes of 34 patients with acute CSC underwent mfERG and OCT examinations. First-order mfERG N1 and P1 response amplitudes and latencies were analyzed.OCT parameters measured included central subretinal fluid (SRF) thickness, central retinal thickness, total central foveal thickness, vertical, and horizontal diameters of SRF, and macular volume. Correlation analyses were performed between best-corrected visual acuity (BCVA), mfERG parameters, and OCT measurements. Correlation analysis showed that logMAR BCVA was significantly correlated with mfERG N1 amplitudes of rings 1 and 2 (P = 0.006), N1 latency of ring 4 (P = 0.012), and P1 latency of ring 1 (P = 0.036). No significant correlation was observed between logMAR BCVA and any of the OCT measurements. For the correlation between mfERG parameters and OCT measurements, mfERG N1 and P1 latencies of the paracentral rings were significantly correlated with the central SRF thickness (P < or = 0.024), diameters of the SRF (P < or = 0.018), and macular volume (P < or = 0.030). MfERG responses but not OCT measurements correlated with logMAR BCVA in patients with acute CSC. The amount of SRF nonetheless correlated with the mfERG N1 and P1 latencies of the paracentral rings, suggesting that impairment in the conduction of electrical responses in the paracentral macula is proportional to the severity of serous macular detachment in CSC. MfERG and OCT can complement each other in the functional and anatomical assessments in CSC.

First and second-order kernel multifocal electroretinography abnormalities in acute central serous chorioretinopathy

PURPOSE

To evaluate the first and second-order kernel multifocal electroretinogram (mfERG) response abnormalities in patients with acute central serous chorioretinopathy (CSC).

METHODS

This was a cross-sectional observational study in which 45 eyes of 45 patients with acute CSC underwent mfERG recordings. Peak amplitudes and implicit times of the first and second-order kernel responses were analyzed and compared with 20 age-matched normal controls. Correlation analyses were performed between the patients' visual acuity and the first and second-order amplitudes and implicit times.

RESULTS

The first-order N1 and P1 mfERG amplitudes in the central three concentric rings were reduced in eyes with acute CSC compared with controls (P < 0.05). The first-order P1 implicit times of the central four rings were also delayed (P < 0.05). For the second-order mfERG response, there were significant reductions in the second-order P1 and N1 amplitudes in rings 3-5 compared with controls (P < 0.05). No significant difference between the second-order P1 and N1 implicit times was found compared with controls (P > 0.05). Correlation analyses showed significant correlations between visual acuity and the first-order N1 response amplitudes of rings 1 and 2, and for the first-order N1 and P1 implicit times of rings 1-4 (P < 0.05).

CONCLUSION

Both first and second-order mfERG response abnormalities occur in eyes with acute CSC. These results suggest that in acute CSC, while outer retinal dysfunction is mostly localized to the central macula, there might be more widespread impairment in adaptive mechanisms of the inner retina or outer plexiform layer dysfunction in the more peripheral macula.

The clinical applications of multifocal electroretinography: a systematic review

Multifocal electroretinography (mfERG) is an investigation that can simultaneously measure multiple electroretinographic responses at different retinal locations by cross-correlation techniques. mfERG therefore allows topographic mapping of retinal function in the central 40-50 degrees of the retina. The strength of mfERG lies in its ability to provide objective assessment of the central retinal function at different retinal areas within a short duration of time. Since the introduction of mfERG in 1992, mfERG has been applied in a large variety of clinical settings. This article reviews the clinical applications of mfERG based on the currently available evidence. mfERG has been found to be useful in the assessment of localized retinal dysfunction caused by various acquired or hereditary retinal disorders. The use of mfERG also enabled clinicians to objectively monitor the treatment outcomes as the changes in visual functions might not be reflected by subjective methods of assessment. By changing the stimulus, recording, and analysis parameters, investigation of specific retinal electrophysiological components can be performed topographically. Further developments and consolidations of these parameters will likely broaden the use of mfERG in the clinical setting.

Microdot test of foveal function. A comparison with visual acuity at high and low contrast

PURPOSE

To define normal values across age from novel computerized tests of foveal vision and to compare the findings with visual acuity (VA) at high and low contrast.

SUBJECTS AND METHODS

Sixty-one healthy volunteers, aged 22-87, with subjectively normal vision participated in the study. The right eye from each subject was tested with Snellen letter VA at high contrast, at 10% contrast using the Tri-VA test and with the Rarebit Microdot Fovea Test (RMFT), in addition to biomicroscopy and fundus examination.

RESULTS

The median letter VA was 0.77 minimum angle of resolution (MAR; range 0.63-1.54) with a significant decline in letter VA with increasing age (r = 0.7, p < 0.001). The median Tri-VA resolution threshold at 10% contrast was 1.8 MAR (range 0.9-4.1) and a significant age effect (r = 0.7) was observed, most pronounced above 65 years. The median RMFT hit rate was 100% (range 97-100) in the age group below 65 years and 87.5% (range 34-98) in subjects older than 65 years.

CONCLUSION

The study shows a decline in foveal function with age with all three methods, reflecting the loss of neural detectors with increasing age. The hit rate to microdot stimuli appears to be a sensitive measure, which can be used for fine-graded evaluation of foveal function.