Changes in Inner and Outer Retinal Layer Thicknesses after Vitrectomy for Idiopathic Macular Hole: Implications for Visual Prognosis.
OBJECTIVE
To investigate sequential post-operative thickness changes in inner and outer retinal layers in eyes with an idiopathic macular hole (MH).


METHODS
Retrospective case series. Twenty-four eyes of 23 patients who had received pars plana vitrectomy (PPV) for the closure of MH were included in the study. Spectral domain optical coherence tomography C-scan was used to automatically measure the mean thickness of the inner and outer retinal layers pre-operatively and up to 6 months following surgery. The photoreceptor outer segment (PROS) length was measured manually and was used to assess its relationship with best-corrected visual acuity (BCVA).


RESULTS
Compared with the pre-operative thickness, the inner layers significantly thinned during follow-up (P = 0.02), particularly in the parafoveal (P = 0.01), but not perifoveal, area. The post-operative inner layer thinning ranged from the ganglion cell layer to the inner plexiform layer (P = 0.002), whereas the nerve fiber layer was unaltered. Outer layer thickness was significantly greater post-operatively (P = 0.002), and especially the PROS lengthened not only in the fovea but also in the parafovea (P < 0.001). Six months after surgery, BCVA was significantly correlated exclusively with the elongated foveal PROS (R = 0.42, P = 0.03), but not with any of the other thickness parameters examined.


CONCLUSIONS
Following PPV for MH, retinal inner layers other than the nerve fiber layer thinned, suggestive of subclinical thickening in the inner layers where no cyst was evident pre-operatively. In contrast, retinal outer layer thickness significantly increased, potentially as a result of PROS elongation linking tightly with favorable visual prognosis in MH eyes.
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Yuki
Y
Hashimoto
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan; Department of Ocular Circulation and Metabolism, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Wataru
W
Saito
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Akio
A
Fujiya
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Chikako
C
Yoshizawa
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Kiriko
K
Hirooka
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Shohei
S
Mori
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan; Department of Ocular Circulation and Metabolism, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Kousuke
K
Noda
Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan; Department of Ocular Circulation and Metabolism, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Susumu
S
Ishida
D000368:Aged; D005260:Female; D005584:Fovea Centralis / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D012167:Retinal Perforations / Q000473:pathology*; D055214:Retinal Photoreceptor Cell Outer Segment / Q000473:pathology*; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence / Q000379:methods; D014792:Visual Acuity / Q000502:physiology; D014821:Vitrectomy / Q000379:methods