To analyze the long-term dynamic healing process of outer retinal changes for 1 year in patients who underwent a standard vitrectomy procedure for idiopathic macular hole (MH) repair.
Retrospective, consecutive, observational case series.
Data were collected on 60 eyes of 56 patients (30 women, 26 men) that underwent successful pars plana vitrectomy (PPV) and internal limiting membrane (ILM) peeling for idiopathic MH from January 2011 to December 2012. The age distribution ranged from 56 to 85 years (mean: 64 years). Forty eyes underwent combined phacoemulsification, PPV, ILM peeling, and intraocular lens implantation; 20 preoperative pseudophakic eyes underwent PPV and ILM peeling only. The main outcome measures included logMAR best-corrected visual acuity (BCVA) and macular microstructures determined by spectral-domain optical coherence tomography performed pre- and postoperatively during follow-up visits at 1, 3, 6, 9, and 12 months.
One month after surgery, 24 eyes (40%) showed normal external limiting membrane (ELM), 36 eyes (60%) showed normal ELM at 3 months, and 54 eyes (90%) showed normal ELM 12 months after surgery. Six eyes (10%) revealed a continuous ellipsoid zone (EZ) at 1 month, 18 eyes (30%) at 3 months, and 48 eyes (80%) at 12 months postoperatively. There were no eyes with a disrupted ELM in the presence of an intact EZ line. The eyes with intact ELM and/or intact EZ line showed better BCVA than eyes with defects in ELM or EZ line. On the contrary, glial cell presentation is significantly associated with worse postoperative BCVA. However, the presence of foveal cystoid change is not significantly associated with postoperative BCVA.
The ELM and EZ line at the fovea recovered and the presence of glial cells and cystoid space resolved gradually after surgery. The postoperative visual acuity was correlated with resolved glial cells and a restored ELM and EZ line.
Idiopathic macular hole (MH) is a common retinal disease mostly affecting elderly people. Interest in the disease has increased dramatically since effective surgical treatment became available about 20 years ago. Kelly and Wendel first reported that vitrectomy followed by a gas tamponade is effective for the treatment of idiopathic MH. Since then, idiopathic MH surgery has resulted in successful hole closure and significant visual improvement in over 85% of cases. However, the postoperative visual acuity (VA) is occasionally poor despite anatomic closure. Histopathologic studies from autopsy eyes with idiopathic MH revealed some microstructure changes, such as cystic structure and disruption of the photoreceptor layer. Recently some reports have correlated the visual outcome with underlying anatomic macular changes by using optical coherence tomography (OCT). Conventional time-domain OCT (TD OCT) with 10 μm resolution has very limited capability to detect pathologic photoreceptor changes. Recently developed spectral-domain OCT (SD OCT) with 5-μm high resolution has allowed observation of the ellipsoid zone (EZ, previously known as photoreceptor inner segment and outer segment [IS/OS]) and external limiting membrane (ELM). Recently published reports showed that the postoperative status of the EZ layer significantly correlates with the visual outcome of idiopathic MH surgery. There is a paper recruiting eyes following retinal detachment repair that showed that combined disruptions of ELM and EZ result in worse visual outcomes compared with eyes with isolated EZ disruptions. However, the findings that predict potential restoration of the photoreceptor microstructure and subsequent visual recovery in surgically closed idiopathic MH have not been fully clarified, and the follow-up period is usually 6 months or less, which is relatively short. The purpose of this study is to determine the long-term correlation between the dynamic postoperative visual outcome and the restoration of foveal microstructures after successful idiopathic MH surgery.
Patients and Methods
The study design was a retrospective, consecutive, observational case series. This study was performed with the approval of the Institutional Review Board of Kaohsiung Medical University Hospital. The described research adhered to the tenets of the Declaration of Helsinki (1964). Sixty patients who were diagnosed as having idiopathic MH and had undergone anatomically successful MH surgery in Kaohsiung Medical University Hospital between January 1, 2011 and December 31, 2012 were included. We excluded eyes with a retinal detachment–associated MH, a traumatic MH, or high myopia–associated MH (which was defined as an eye with a refractive error of more than −8.00 diopters or myopia with an axial length more than 27.0 mm). Preoperatively, a complete medical and ophthalmic history was obtained, and a detailed eye examination including measurement of Snellen best-corrected visual acuity (BCVA), intraocular pressure, slit-lamp examination of lens status, thorough fundus examination by indirect binocular ophthalmoscopy, and foveal microstructures scanned by SD OCT (Heidelberg Retina Angiograph 2; Heidelberg Engineering, Heidelberg, Germany) were performed. According to the scanning protocol, radial 20-degree, 6-line scans centered on the fovea were obtained for each eye. More than 25 scans were averaged for each measurement. Only images with a quality score of more than 25 were selected as high-quality images. The integrity of the EZ and ELM was evaluated by using the photoreceptor EZ and ELM line on the gray-scale SD OCT images. Both the ELM line and the photoreceptor EZ were evaluated on each of the radial 6-line scans for 500 μm in either direction of the center of the fovea and were defined as intact when the line was continuous. Regarding glial proliferation, we defined it as the presence of moderately to highly reflective lesion on SD OCT involving the outer aspect of the fovea.
The surgery was performed by 1 retina specialist (W.C.W.). A standard sutureless (25 gauge) 3-port pars plana vitrectomy (PPV) was used to close the MH. An intravitreal injection of indocyanine green, which was diluted to 5 mg/mL concentration using 5% glucose water, was performed to make the internal limiting membrane (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. The lens was extracted by phacoemulsification with an implantation of an intraocular lens (IOL) for all patients with preoperative phakic condition. Twenty percent sulfur hexafluoride was used to tamponade the retina, and patients were instructed to maintain a face-down position for 7 days postoperatively. After surgery, complete ophthalmic examination and SD OCT examinations were performed 1, 3, 6, 9, and 12 months postoperatively. Snellen BCVA was converted to logarithm of the minimal angle of resolution (logMAR) to evaluate vision changes.
The mean age of patients was 64 years (range, 56–85 years). Preoperative mean logMAR BCVA was 0.95 (range, 0.15–2.0). Forty eyes underwent combined phacoemulsification, PPV, ILM peeling, and IOL implantation; 20 preoperative pseudophakic eyes underwent PPV and ILM peeling only.
With regard to the postoperative features of the outer retina, the ELM was restored much earlier than the EZ. Twenty-four of the 60 eyes (40%) showed a normal ELM at 1 month after surgery, 36 eyes (60%) at 3 months, 40 eyes (66.7%) at 6 months, and 54 eyes (90%) at 12 months after surgery ( Figure 1 ). Our results demonstrate that ELM gradually regains its continuity and is well correlated with BCVA ( Figure 2 ).
Six of 60 eyes (10%) revealed a continuous EZ at 1 month, 18 eyes (30%) at 3 months, 27 eyes (45%) at 6 months, and 48 eyes (80%) at 12 months postoperatively ( Figure 1 ). The EZ junction is also a useful indicator of visual function after MH repair. The EZ gradually reconstructed and is also significantly associated with BCVA ( Figure 3 ). The ELM and EZ reconstruction are both significantly correlated with BCVA at postoperative 1, 3, 6, and 12 months ( Figures 2 and 3 ). There were no eyes with a disrupted ELM in the presence of an intact EZ. The eyes with intact ELM and/or intact EZ showed better BCVA than eyes with defects in ELM or EZ ( Figures 2 and 3 ).
Presence of glial cells, which was defined as a hyperreflective foveal lesion on OCT, was noted in 28 eyes (46.7%) at 1 month, 23 eyes (38.3%) at 3 months, 17 eyes (28.3%) at 6 months, and 6 eyes (10%) at 12 months postoperatively ( Figure 1 ). Glial cell presentation is significantly associated with worse logMAR BCVA at 1, 3, 6, and 12 months postoperatively ( Figure 4 ).
Foveal cystoid change was visible in 23 of 60 eyes (38.3%) at 1 month, 17 eyes (28.3%) at 3 months, 7 eyes (11.7%) at 6 months, and 5 eyes (8.3%) at 12 months postoperatively. The cystic space resolved gradually in most of the cases, leaving 5 eyes with persistent foveal cystoid change. It is noteworthy that the presence of a foveal cystoid change is not significantly associated with better or worse logMAR BCVA ( Figure 5 ). Figure 6 demonstrates a patient regaining ELM continuity 1 month post operation and eventually restoring intact EZ 12 months after operation. Figure 7 shows a patient with foveal cystoid change 1 month post operation; unfortunately, glial tissue replaced the foveal cystoid change, with relatively poor visual prognosis.