Changes in first- and second-order multifocal electroretinography in idiopathic macular hole and their correlations with macular hole diameter and visual acuity

Functional features in patients with idiopathic macular hole treatment via OCT angiography

To evaluate the optical coherence tomography (OCT) angiography features in patients with idiopathic macular hole (IMH) before and after vitrectomy. This prospective study included 25 patients diagnosed with IMH in Shanxi eye hospital from August 2019 to December 2021. The study was divided into 3 groups: IMH eyes, fellow eyes and normal eyes. All unilateral IMH eyes underwent vitrectomy. There were significant differences in superficial retinal blood flow density (SRBFD, P < .001) and choroidal blood flow density (CBFD) between IMH and healthy control eyes before operation (P < .05). There was significant difference in SRBFD between fellow eyes and normal eyes (P = .038). The changes of SRBFD and CBFD in IMH eyes before and after operation were statistically significant (P < .05). The CBFD at 6 months after operation is negatively correlated with LogMAR visual acuity, and the CBFD of the fellow eye is also negatively correlated with LogMAR visual acuity. The SRBFD and CBFD had no correlation with the diameter of macular hole before and after operation. SRBFD and CBFD increased after vitrectomy, indicating that the blood supply of retina and choroid were partially restored after vitrectomy. There was no correlation between SRBFD, CBFD and hole diameter, but there was correlation between choroidal blood flow and LogMAR visual acuity.

Morphological and Functional Features in Patients with Idiopathic Macular Hole Treatment

Purpose

To evaluate the multifocal electroretinogram (mfERG) and optical coherence tomography (OCT) angiography features in patients with idiopathic macular hole (IMH) before and after vitrectomy.

Patients and Methods

This prospective study was conducted at Shanxi Eye Hospital from January 2019 to December 2021. Twenty-five eyes of 25 patients with unilateral IMH, the unaffected fellow eyes, and 30 eyes of healthy patients were investigated. All unilateral IMH eyes underwent vitrectomy.

Results

The IMH eyes had significantly delayed latency (rings 2-5) of mfERG compared with the healthy control eyes, and the amplitude density of all rings of mfERG was reduced (P < 0.05). When comparing the mfERG components before surgery and at the follow-up, the amplitude density of IMH eyes (ring 1, 3, 4 and 5) was increased significantly (P < 0.05). The delayed implicit times of the second and fifth ring were significantly shortened compared with those of preoperative eyes (P < 0.05). The mean delayed implicit time of mfERG in six months after surgery was negatively correlated with visual acuity (r = -0.890, P = 0.043). Significant differences of superficial retinal blood flow density (SRBFD, P < 0.001) and choroidal blood flow density (CBFD) (P < 0.05) got via OCTA were found between IMH before surgery and healthy control eyes. SRBFD of the fellow eyes were significantly different with the healthy control eyes (P = 0.038). Statistically significance of SRBFD and CBFD changes in IMH eyes were found before and after surgery (P < 0.05).

Conclusion

IMH eyes had a decreased amplitude density and a delayed implicit time in some regions. Additionally, SRBFD and CBFD were both increased after vitrectomy, which suggests that the blood supply of the retina and choroid is partially restored after vitrectomy.

Correlation between Postoperative Area of High Autofluorescence in Macula and Visual Acuity after Macular Hole Closure

PURPOSE

To determine the correlation between the preoperative basal diameter of macular hole, the postoperative area of high autofluorescence (AF) in macula, and visual acuity in full-thickness macular hole.

METHODS

Forty-nine patients with full-thickness macular hole who underwent vitrectomy and C₃F₈ filling were reviewed. The preoperative diameter of macular hole, the 6 months postoperative area of high AF in macula if it existed, the length of inner segment/outer segment (IS/OS) defect, and visual acuity were obtained. The correlation between them was determined.

RESULTS

At postoperative 6 months, the rate of high AF in macula was 63.3%. There were statistical differences between with and without high AF groups in postoperative best-corrected visual acuity (BCVA) (t = -2.751, p = 0.008), preoperative basal diameter of macular hole (t = -4.946, p = 0.00001), and postoperative length of IS/OS defect (t = -8.351, p<0.00001). Simple linear regression analysis showed high positive correlations between preoperative basal diameter of macular hole and area of high AF (p<0.00001, r = 0.893), postoperative length of IS/OS defect and area of high fundus AF (FAF) (p<0.00001, r = 0.779), and negative correlations between area of high AF and postoperative BCVA (p = 0.037, r = 0.375). There was low correlation between diameter of macular hole and postoperative BCVA (p = 0.112).

CONCLUSIONS

The preoperative basal diameter of macular hole and postoperative length of IS/OS defect decides the postoperative area of high AF in macula to some degree, and the postoperative area of high AF in macula can be an evaluating indicator for poor macular function recovery.

[Electrophysiological parameters of the retina in idiopathic macular hole]

AIM

To investigate the nature and range of electrophysiological disturbances in idiopathic macular hole (IMH) and establish their relationship with structural parameters of the retina.

MATERIAL AND METHODS

The study included 249 patients (280 eyes) with IMH. All of them underwent ganzfeld and multifocal electroretinography (ERG), optical coherence tomography, and evaluation of retinal electrical sensitivity and analyzer lability. The results were then compared to those of non-IMH patients (196 paired eyes) and controls (25 people, 49 eyes).

RESULTS

Multifocal ERG findings prove that IMH is always associated with significant changes in bioelectrical potential of the central retina. In 62% of cases its decreased density and extended latency were registered in not only the fovea, but also the para- and perifovea. In 8% of cases the changes involved everything within a 30-degree area of the central retina. In 30% of cases the maximum bioelectric potential was found to have shifted from the centre to para- and perifovea, its amplitude and density being supernormal for these regions (shift phenomenon). A weak correlation between electrophysiological parameters and retinal thickness around the hole has been also established.

CONCLUSION

Of all methods used to assess retinal function in IMH, multifocal ERG is the most informative. In 100% of cases foveal biopotential is sharply reduced in density and disfigured. In 70% of cases these changes spread outside the fovea.

Fixation stability and implication for multifocal electroretinography in patients with neovascular age-related macular degeneration after anti-VEGF treatment

PURPOSE

To quantify fixation stability in patients with neovascular age-related macular degeneration (nAMD) at baseline, 3 and 6 months after anti-vascular endothelial growth factor (anti-VEGF) treatment and furthermore asses the implications of an unsteady fixation for multifocal electroretinography (mfERG) measurements.

METHODS

Fifty eyes of 50 nAMD patients receiving intravitreal anti-VEGF treatment with either bevacizumab or ranibizumab and eight eyes of eight control subjects were included. Fixation stability measurements were performed with the Eye-Link eyetracking system and the retinal area in degrees² (deg²) containing the 68 % most frequently used fixation points (RAF68) was calculated. MfERG P1 amplitude and implicit time were analyzed in six concentric rings and as a summed response. Patients were examined at baseline, 3 and 6 months. Four different mfERG recordings were performed for the control subjects to mimic an involuntary unstable fixation: normal central fixation, 2.4°, 4.8°, and 7.1° fixation instability.

RESULTS

For control subjects, a fixation instability of 2.4° (corresponding to the central hexagon) did not reduce mfERG ring amplitudes significantly, whereas 4.8° and 7.1° fixation instability reduced the amplitudes significantly in rings 1 and 2 (p < 0.001) as well as in the peripheral rings in the 7.1° instability condition (p < 0.001). Fixation stability improved non-significantly for patients at 3 and 6 months. The size of the retinal area of fixation was at baseline, 3 and 6 months negatively correlated to visual acuity (VA) (r_baseline = -0.65, r_{3 months} = -0.60, and r_{6 months} = -0.66 respectively, p < 0.001) and mfERG amplitudes of the three innermost rings (r_baseline = -0.29, p = 0.042, r_3 months = -0.43, p = 0.003 and r_6 months = -0.31, p = 0.042). The VA cutoff for a fixation area less than 5 deg² (approximately the central hexagon) was 65, 77, and 68 ETDRS letters (corresponding a maximal Snellen equivalent of 0.31) at baseline, 3 and 6 months, respectively.

CONCLUSIONS

MfERG amplitudes in recordings of nAMD patients are at substantial risk of being reduced due to poor fixation as a large number of patients may use a fixation area of more than 5 deg². Fixation monitoring during recording as well as interpretation of results should be performed with care, especially in patients with poor visual acuity.

Cone implicit time as a predictor of visual outcome in macular hole surgery

PURPOSE

To investigate whether preoperative retinal function measured by full-field ERG and multifocal ERG is correlated to postoperative visual acuity after macular hole surgery.

METHODS

Standard pars plana vitrectomy with removal of the internal limiting membrane (ILM) was performed on 19 consecutive patients undergoing macular hole surgery. Intraocular gas tamponade with a C2F6 gas-air mixture was employed, followed by a face-down position for at least 5 days. The patients were examined with the ETDRS chart, full-field ERG (Espion), multifocal ERG (Veris 6), and optical coherence tomography (OCT) preoperatively, and 6 weeks, 6 months, and 18 months after surgery.

RESULTS

The cone 30-Hz flicker implicit time in the full-field ERG reflecting retinal function was prolonged (p = 0.016) before surgery compared to aged-matched controls. After macula hole surgery, longstanding alteration of cone function reflected by mfERG and full-field ERG was verified 18 months after surgery. The prolonged cone 30-Hz flicker implicit time in the full-field ERG before surgery was significantly correlated to the ETDRS visual acuity 6 months postoperatively (p = 0.03).

CONCLUSIONS

Preoperative evaluation of retinal function with multifocal ERG and full-field ERG improves the understanding of the retinal recovery process after macular hole surgery. The cone implicit time in full-field 30-Hz flicker ERG could be a valid predictor of long-term visual outcome, which may be useful for selecting patients suitable for surgery.