Contribution to the Investigation Macular Function for the Surgical Treatment of Idiopathic Macular Holes

Summary

We evaluate annual anatomical and functional results of standard 20G pars plana vitrectomy for idiopathic macular hole, with peeling MLI (membrana limitans interna) and instillation of gas tamponade (20% SF6 – sulfur hexafluoride)

The observed group consisted of 32 eyes of 32 patients (3 men and 29 women), mean age 69 years (range 59–76). There was no other ocular pathology besides idiopathic macular holes (IMD). Objectification of ocular anatomy was done with: anterior segment slit lamp, the biomicroscopy in artificial mydriasis and optical coherence tomography (Stratus OCT ™, Carl Zeiss). For examination of the central area of the retina was evaluated: the best corrected visual acuity in the distance (BCVA) with ETDRS optotype, BCVA in the near (Jaeger charts), multifocal electroretinography (MfERG) and pattern reversal electroretinography (PERG).

For the statistical processing of results we used non-parametric Wilcoxon paired test.

Anatomical results:
the primary closure of the IMD occurred in 29 (90 %), the IMD was not closed, but it’s edges were flattened in 2 eyes (6 %), and once time the edges of the IMD were not flattened (3 %).

Functional results:
the initial BCVA ranged from 0.1 to 0.5 (1.0 to 0.3 LogMAR). After one year of operations the visual acuity improved by 2 or more lines in 27 eyes (84%), of 3 or more lines in 18 eyes (56%), and 4 or more lines in 5 eyes (16%). PERG amplitudes (N95) in all eyes were between 4 to 9 μV (within the normal range of the laboratory), and was not found statistically significant difference between the values before surgery and 12 months after. Statistically significant difference (improvement) was found in the first and the second central ring of the MfERG. Improvement involved the values of P1 wave amplitude before surgery and 12 months after (Wilcoxon p < 0.01). The difference between the values of N1 and P1 latencies before surgery and month 12 was not statistically significant, as well as changes between the values of the amplitudes of waves N1 preoperatively and 12 months later.

Due to the favorable anatomical and functional results we consider surgical treatment of macular holes through PPV with peeling MLI as a safe technique. When the indication to perform peeling is considered, there is a need to think about other factors, especially duration IMD, disease stage, type of intraocular tamponade and the patient’s cooperation.

Key words:
MLI, peeling, macular hole, MfERG, PERG