Of the 193 eyes of 185 patients that underwent macular hole surgery between July 2009 and March 2012 at the Kyorin Eye Center, eyes with any macular disease other than macular hole, other retinal diseases, glaucoma, other optic nerve diseases, and high myopia (refractive errors greater than −8.0 diopters or axial length more than 26.0 mm) were excluded. Only the medical records of consecutive patients with a surgically closed idiopathic macular hole and follow-up times of at least 6 months were reviewed. All patients were diagnosed with either a stage 2, 3, or 4 idiopathic macular hole according to Gass' classification. The preoperative data collected included the age, sex, right or left eye, stage of macular hole, Snellen BCVA, length of the ELM line, IS/OS line, and COST line defect, the distance from the optic disc margin to the fovea or center of macular hole, and cross-sectional retinal area from the disc margin to the edge of macular hole or the disc margin to the fovea. The BCVA was measured by the same examiner in the same room under similar illumination. The decimal BCVA was converted to logMAR units for the statistical analyses.
All of the patients had a comprehensive ophthalmologic examination before and 6 and 12 months after the surgery. The examinations included fundus examinations by binocular indirect ophthalmoscopy and noncontact lens slit-lamp biomicroscopy, fundus photography, and fundus autofluorescence imaging by confocal scanning ophthalmoscopy (Heidelberg Retina Angiograph 2; Heidelberg Engineering, Heidelberg, Germany). Cross-sectional images of the macular area were obtained by SD-OCT (Spectralis; Heidelberg Engineering). These examinations were performed on the same day in all patients.
All surgeries were performed after the patients received a detailed explanation of the surgical and SD-OCT procedures. An informed consent was obtained from all patients, and the procedures used adhered to the tenets of the Declaration of Helsinki. The study protocol was approved by the Institutional Review Committee of the Kyorin University School of Medicine, and all of the patients consented to our review of their medical records. This clinical study has been registered at the United States National Institutes of Health (
www.clinicaltrials.gov) as “Asymmetrical Recovery of Cone Outer Segment Tips and Foveal Displacement After Macular Hole Surgery” with a reference number of NCT01959776. The main outcome measures were the length of cone outer segment tips line defect from the fovea and papillofoveal distance in the SD-OCT images.
The surgery was performed by one of the three retina specialists (YI, MI, AH). A standard three-port pars plana vitrectomy (PPV) was used to close the macular hole under 2% lidocaine retrobulbar anesthesia. An intravitreal injection of triamcinolone acetonide (MaQaid; Wakamoto Pharmaceutical Co., Ltd., Tokyo, Japan or Kenacort-A; Bristol Pharmaceuticals KK, Tokyo, Japan) was used to make the vitreous gel and ILM more visible. Core vitrectomy was performed with the creation of a posterior vitreous detachment if it was not present, and the ILM was removed in all cases. Internal limiting membrane was peeled in an area of 1 to 2 disc diameters around the macular hole symmetrically. The lens was extracted from all patients aged >55 years; and all cataractous lenses were removed by phacoemulsification with an implantation of an intraocular lens. Room air or nonexpansive 20% sulfur hexafluoride (SF6) was used to tamponade the retina, and the patients were instructed to maintain a facedown position for 3 to 4 days after the surgery. Anatomical success was defined as the presence of a flat and closed macular hole postoperatively as confirmed by slit-lamp biomicroscopy, SD-OCT, and the absence of autofluorescence at the site of the macular hole.
The macular area was scanned with the SD-OCT instruments with at least 70 repeated scans, and high quality 9-mm scan images were obtained. The lengths of the ELM line defect, IS/OS line defect, and COST line defect across the fovea in the horizontal and vertical scans were measured on the SD-OCT images using software embedded in the instrument. The center of the macular hole was determined to be the anatomical center of the dehiscent macular hole preoperatively. The foveal center or the center of the closed macular hole was defined as the hyperreflective junction of the closed macular hole or the center of foveal depression in the SD-OCT images. The inner retinal layers from the nerve fiber layer to Henle's layer were observed in the periphery and, when traced to the fovea, these layers disappeared as reported.
25 The center point of this area was considered to be the foveal center.
The length of the ELM line, IS/OS line, and COST line defects in the temporal, nasal, superior, and inferior sectors—i.e., the Early Treatment Diabetic Retinopathy Study sectors—were also measured in the SD-OCT vertical and horizontal images. Preoperatively, the length of the ELM line defect, IS/OS line defect, and the COST line defects were measured from the center of the macular hole.
The papillofoveal distance was measured manually as the distance between the center of the macular hole or the fovea and the optic disc margin in the SD-OCT images of the horizontal section across the fovea using software embedded in the instrument (
Fig. 1). To determine the papillofoveal cross-sectional area between the fovea and the optic disc margin, the SD-OCT images of 9-mm width were uploaded to a computer, and the total number of pixels of the sensory retinal area between the optic disc margin and the center of macular hole or the fovea was counted with the ImageJ software (
http://imagej.nih.gov/ij/; provided in the public domain by the National Institutes of Health, Bethesda, MD, USA). The areas of fluid including intraretinal cyst or subretinal fluid were subtracted to evaluate only the cellular components of the papillofoveal cross sections (
Fig. 2). Two experienced investigators (YI, TR), who were masked to the patients' information including the postoperative period and the BCVA, measured the length of COST line, IS/OS line, and ELM line defects and papillofoveal distance on each SD-OCT image independently.
The Mann-Whitney U tests were used to compare two groups. For multiple comparisons, the three sets of data were analyzed using one-way ANOVA and Kruskal-Wallis tests. Multivariate analyses were also performed to determine which sector of COST line defect was correlated with the BCVA preoperatively, and at 6 and 12 months after surgery.