We retrospectively reviewed patients' medical records who underwent PPV due to MHRD between 2014 and 2019 at Infanta Leonor University Hospital in Madrid.
The hospital's Institutional Review Board approved, and it adhered to the tenets of the Declaration of Helsinki. All patients provided written informed consent not only for the surgery but also for the use of data for future research studies.
High myopia was defined as axial length > 25mm. MHRD was diagnosed with a dilated slit-lamp binocular ophthalmoscopy and spectral domain optical coherence tomography (OCT) when possible.
The inclusion criteria were clinical presentation of MHRD, macular hole being the primary cause of the detachment, 18 years or older, and follow up period more than 12 months after surgery. Exclusion criteria were presence of choroidal neovascularization, proliferative vitreoretinopathy changes or trauma before the surgery.
Clinical information was collected from medical records. It included, age, sex, axial length, preoperative lens status, preoperative and postoperative best-corrected visual acuity (BCVA), lens status, operative variables including type of technique and type of tamponade, presence or absence of retina reattachment, MH closure (absence of neurosensory defect over the retina) and external retina preservation (EZ (ellipsoid zone) and external limiting membrane (ELM)).
BCVA was measured in decimal unit and converted to a of minimal angle of resolution (logMAR) logarithm for statistical analysis. Axial length was determined with A-scan ultrasonography (OPKO instrumentation, OTI-Scan 3000). In cases where the axial length measurement was artifactiously low, the error was corrected using a caliper to evaluate the distance from the cornea to the surface of the retinal pigment epithelium. Slit lamp examination of the posterior segment and OCT examinations centred on the fovea were performed at least 6 months after surgery in all patients.
Experienced vitreoretinal surgeons conducted all procedures. Standard phacoemulsification was performed before vitrectomy in those patients with associated cataract. All patients underwent 23-gauge vitrectomy with posterior vitreous detachment. The surgical posterior hyaloid detachment was performed with triamcinolone (2.5mh/ml) when needed. Membrane dual-blue was used in all cases for staining around the MH. If an epiretinal membrane was present, it was peeled. In all patients, air-fluid exchange was done, and the air was then replaced with non-expansive gas, either perfluoropropane (C3F8) or sulfur hexafluoride (SF6), or silicone oil (for patients who could not keep a prone position or severe cases).
To evaluate functional and anatomical results between the two techniques, the patients were divided into two groups based on the surgical procedure: PPV and ILM peeling, 5 eyes (group 1), and the superior inverted ILM flap and capsulorhexis technique,4 eyes (group 2).
Techniques:
Group 1: ILM within the arcades was completely removed after membrane staining. Group 2: after membrane staining a 360º ILM macular rhexis was done, leaving just a central flap about 2-disc diameters in size, attached to the retina. The flap was inverted to cover the MH from its superior margin. A small amount of PFC was introduced to keep the flap in position (Fig. 1).
Subretinal fluid was drained through an iatrogenic break outside the staphyloma. Slow fluid-air exchange and laser photocoagulation around the break was performed.
The statistical analysis was performed using SPSS (version 21.0) to analyse the differences in baseline characteristics, anatomical and functional outcomes between groups.
Two-sample t tests were used to calculate differences in age, axial length, pre and post logMAR visual acuity and improvement in logMAR VA between the 2 groups. The chi-square test (Fisher exact test if n < 5) was used to calculate differences between sex, lens status, MH closure rates and external retina preservation. A p-value of 0.05 was considered to represent a statistically significant difference.