Abstract
Purpose: :
To investigate the visual and anatomic outcomes in patients with chronic macular edema who underwent 25-gauge pars plana vitrectomy (PPV) with internal limiting membrane (ILM) removal.
Methods: :
This is a retrospective, consecutive case series of patients operated at a single university medical center by a single surgeon. Patients who underwent microcannula-based sutureless 25-gauge PPV and ILM peeling after indocyanine green staining for chronic macular edema (CME) were included. Pre- and postoperative spectral-domain optical coherence tomography (OCT) was examined for macular thickness (MT) and macular volume (MV). Visual and anatomic outcomes were analyzed using two-tailed t-test. Preoperative factors possibly associated with the visual and anatomic outcomes were evaluated using Spearman’s rank correlation coefficient.
Results: :
Twenty-four eyes of 11 men and 10 women were included (mean age 69). Four patients (17%) had CME from uveitis, 4 (17%) from retinal vein occlusion, and 18 (75%) from diabetes. Seventy-five percent of the eyes had previously been treated with macular laser or intravitreal injection. The mean visual acuity (VA) was 20/103, 20/87, pre- and post-op respectively (P=0.55). Sixty-three percent of the eyes had improved vision (47% better than 20/40), 21% maintained same vision, and 17% had worse vision. Forty-seven percent of improved eyes and 30% of total eyes gained more than 2 lines of VA (range -9 to +7 lines). The mean MT was 455 µm, 396 µm, pre- and post-op (P=0.29). The mean MV was 7.9 mm3 pre-op and 7.5 mm3 post-op (P=0.51). The eyes with more than 2 lines of VA improvement tended to have shorter duration of CME (10 vs 21.7 months), lower HgA1C (6.85 vs 7.62%), and decreased post-op MT (331 vs 409 µm), although the difference did not reach statistical significance. Eyes with posterior hyaloid attached to macula pre-op (confirmed on OCT) tended to have worse visual and anatomic outcome compared to those that had detached posterior hyaloid pre-op (VA 20/125 vs 20/80, p=0.54; MT 481 vs 335 µm, p=0.10; MV 8.55 vs 6.74 mm3, p=0.05). The strongest predictor of post-op VA was initial VA (r=0.673, p=0.0003). Power of our study for comparing the pre and post-op VA only reached 9% due to a small sample size.
Conclusions: :
The majority of patients had improved visual and anatomic outcome after 25-gauge PPV with ILM peeling for CME. A greater sample size may have demonstrated post-op visual outcome that is statistically significant. For patients with refractory and/or persistent macular edema, small-gauge vitrectomy with ILM peeling may be beneficial in helping them reach their maximum visual potential.
Keywords: retina • vitreoretinal surgery • macula/fovea