Electroretinographic changes in eyes with idiopathic macular hole treated by vitrectomy

Retinal sensitivity and fixation changes 1 year after triamcinolone acetonide assisted internal limiting membrane peeling for macular hole surgery--a MP-1 microperimetric study

PURPOSE

To evaluate microperimetric changes 1year after macular hole surgery with triamcinolone acetonide assisted internal limiting membrane (ILM) peeling.

METHODS

Twenty-two eyes of 22 patients with stage 3 and 4 idiopathic macular holes of <6months' duration underwent vitrectomy with triamcinolone acetonide assisted ILM peeling. Best corrected visual acuity (BCVA) (logarithm of the minimum angle of resolution), and central retinal sensitivity were documented before and 1, 3, 6, and 12months after surgery. Macular sensitivity (mean sensitivity in decibels -dB), and stability and location of fixation (preferred retinal locus) were determined using MP-1 microperimetry (Nidek). The MP-1 microperimetry sensitivity map was overlaid onto infrared images recorded on a Heidelberg scanning laser ophthalmoscope using dedicated MP-1 software to evaluate the fixation location before surgery. Anatomical success was evaluated with optical coherence tomography (OCT). Optical coherence tomography scans were recorded on an OCT 3000 scanner.

RESULTS

Anatomical success was achieved in all 22 eyes. All patients completed 1year follow-up. No recurrence of macular hole was seen in any patients in the follow-up period. The mean BCVA improved from 0.75±0.2 before surgery to 0.31±0.1 logMAR at the last visit (p<0.001). Mean sensitivity improved from 3.7±0.6 to 5.3±1.0dB at the last visit (p<0.001). Before surgery, the preferred retinal locus was located on the margin of the hole in all, in 18 eyes on its upper part and in four eyes to the side or on its lower part. Preoperatively, 12 eyes were stable and 10 were relatively unstable, but 12month after surgery, fixation stability had improved, and 20 eyes were stable and two were relatively unstable.

CONCLUSIONS

  MP-1 microperimetry sensitivity map overlaid onto an infrared image using dedicated MP-1 software can be used successfully to evaluate fixation location in patients with a macular hole before surgery. With microperimetry findings, we can also measure functional macular changes more precisely than using BCVA alone after macular hole surgery. Our results also showed that retinal sensitivity and fixation properties were improved after vitrectomy with triamcinolone acetonide assisted ILM peeling in patients with idiopathic macular hole.

"On" response dysfunction in multifocal posterior pigment epitheliopathy

PURPOSE

To determine the electroretinographic properties of one patient with multifocal posterior pigment epitheliopathy.

METHODS

Rod and cone electroretinograms (ERGs) and photopic ERGs elicited by long-duration stimuli were studied in a patient with multifocal posterior pigment epitheliopathy.

RESULTS

The amplitudes of both the rod and cone ERGs were significantly reduced. Photopic ERGs elicited by long-duration stimuli demonstrated that the b-wave ("on" response) was abolished but the d-wave ("off" response) was reduced by only amplitude.

CONCLUSION

The ERG findings in multifocal posterior pigment epitheliopathy indicate that there is dysfunction not only of the photoreceptors but also in the signal transmission specific for the "on" pathway.

Multifocal ERG changes before and after macular hole surgery

To evaluate the visual function of 15 eyes suffering from macular hole the multifocal ERG was used pre and postoperatively. In all the cases a successful vitrectomy has been done with macular hole closure in all the eyes. The Multifocal ERG shows an improvement of retinal response density in regions 1 and 2, even in the 2 eyes with unchanged visual acuity postoperatively. Although a relationship exist between the postoperative retinal response density and the visual acuity, the retinal response density varies between eyes with the same visual acuity.