Abstract
Purpose::
To investigate the relationship between the function and configuration of the macula in cases of the myopic retinoschisis and macular detachment.
Methods::
Eight eyes of 7 patients with myopic retinoschisis (RS group), 6 eyes of 6 patients with myopic retinoschisis and macular detachment (MD group), and 9 eyes of 7 patients with high myopia but without retinoschisis and macular detachment (>6D, control group) were studied (56.7 ± 10.3 years; -11.5 ± 6.2 D). All patients underwent detailed biomicroscopic examination, optical coherence tomography, and focal macular electroretinography (FMERG). The amplitudes of focal ERGs components were compared among the three groups. In 7 eyes, vitreous surgery including internal limiting membrane peeling and C3F8 gas tamponade, was performed and the macular detachment disappeared in all eyes. A slight retinoschisis remained especially near the major vessels. Postoperative FMERGs were recorded from these 3 eyes and were compared with the preoperative FMERGs. Eyes with a macular hole were excluded.
Results::
The amplitudes of the a-wave in the control group, RS group, and MD group were 1.8 ± 0.54 µV, 0.5 ± 0.3µV and 0.1 ± 0.2µV respectively, and the differences among the groups are significant. The amplitudes of the b-wave in the control group, RS group, and MD group were 4.6 ± 1.1 µV, 2.0 ± 0.6 µV and 0.8 ± 0.7µV respectively and the differences among the groups are significant. The amplitudes of the OPs in the control group, RS group, and MD group were 1.5 ± 0.76 µV, 0.3 ± 0.4 µV and 0.0 ± 0.0 µV respectively, and the differences among the groups are also significant. The amplitudes of the a- and b-waves tended to decrease as the retinoschisis and macular detachment increased, and amplitudes of the a-wave tended to decrease more than that of the b-wave. After surgery, the amplitudes of both the a- and b-waves increased and the recovery of the b-wave amplitude tended to be better than that of the a-wave.
Conclusions::
Myopic retinoschisis and macular detachment cause macular dysfunction in all layers, but predominantly in the outer layers. The waveforms of the FMERGs in cases of myopic retinoschisis and macular detachment are different from that of congenital retinoschisis (IOVS 1993), central serous chorioretinopathy (AJO 1988), and epiretinal membrane (AJO 1999), even if the macular configurations are similar. This would indicate that the mechanism of retinal impairment is different in these diseases.
Keywords: macular holes • myopia • electroretinography: clinical