The Use of Amniotic Membrane or Internal Limiting Membrane for Large or Refractory Macular Holes: A Prospective Study

The Use of Amniotic Membrane or Inverted Internal Limiting Membrane Flap for Large or Refractory Macular Holes: a Prospective, Comparative Study Using Microperimetry

Prospective, randomized, unmasked interventional study. To evaluate anatomical and functional results through microperimetry in cases of refractory or large macular holes (MH), using amniotic membrane (AM) or internal limiting membrane ( ILM ).

This study will evaluate functional outcomes through microperimetry in patients undergoing macular hole surgery. It will focus on patients with macular holes ≥600 microns, as well as those with holes refractory to conventional surgical treatment. The study will assess the use of amniotic membrane or internal limiting membrane (ILM) as adjuncts in the macular hole closure process.

The gold-standard treatment for idiopathic macular holes is pars plana vitrectomy (PPV), which involves removal of the posterior hyaloid (when adhered) and the ILM using a vital dye, followed by placement of buffering gas (C3F8 or SF6) at a non-expandable concentration. However, approximately 44% of large macular holes remain unclosed after conventional surgery.

To improve closure rates in such cases, new techniques have been introduced, including the inverted ILM flap technique and the free ILM flap technique. While studies demonstrate the effectiveness of these techniques, they show no significant improvement in visual function.

The amniotic membrane (AM) has recently been explored as an adjunct for macular hole closure and as a substrate for cell growth and visual acuity improvement. Amniotic membranes are believed to promote epithelialization and possess anti-fibrotic, anti-inflammatory, anti-angiogenic, and antimicrobial properties.

In this study, eligible patients will be randomized into two groups:

• Group 1: Undergoing PPV with ILM removal, followed by placement of an amniotic membrane plug inside the macular hole, with its chorionic face in contact with the retinal pigment epithelium (RPE).
• Group 2: Undergoing PPV with ILM removal, followed by placement of either an inverted ILM flap or a free ILM fragment for refractory cases, positioned over (inverted flap) or inside (free flap) the macular hole.

Once the AM plug or ILM flap is confirmed in its correct location, a fluid-gas exchange will be performed with 12.5% C3F8 buffering gas, and patients will maintain a face-down position for 7 days postoperatively.

Patients included in the study will undergo:

• Preoperative assessment, including best-corrected visual acuity (BCVA) measurement, optical coherence tomography (OCT) using the Zeiss Cirrus 5000, and microperimetry using the Macular Integrity Assessment (MAIA) device.
• Postoperative evaluations at day 1 and day 7, followed by assessments at 1, 3, 6, and 12 months. During these visits:- A complete ophthalmic examination will be performed.
• OCT imaging will be conducted at day 7, month 1, month 3, month 6, and month 12.
• Microperimetry will be conducted at months 1, 3, 6, and 12 to evaluate anatomical and functional responses.

The use of the amniotic membrane, given its anti-inflammatory, anti-fibrotic, and cell growth-supporting properties, is expected to increase closure rates in refractory and large macular holes and contribute to better functional outcomes by supporting outer retinal layer regeneration.

The Sorocaba Eye Bank (BOS) will provide, prepare, and preserve the amniotic membrane used in this study.

Inclusion Criteria:

• Patients with a macula hole that falls into the two categories below:
• Patients with idiopathic macular hole (with no history of secondary macular hole) ≥ 600 microns (measured using optical coherence tomography)
• Patients with an idiopathic macular hole submitted to conventional treatment without closing it (of any size).
• History of the disease less than 18 months
• Aged over 18 years old
• Visual acuity less than 20/32

Exclusion Criteria:

• History of any previous macular disease other than idiopathic macular hole
• Macular hole of other causes (secondary)
• Patients with diabetic retinopathy or other retinal vascular diseases
• Eyes subjected to intravitreal injection of any medication
• Visual acuity <20/400 of any retinal cause in the contralateral eye or absence of the globe *Aged under 50 years old
• Cataract and anti-glaucoma surgery less than 3 months before the study
• Glaucoma with optic nerve excavation > 0.7 in the studied eye
• Intraocular pressure > 24 mmHg with the use of maximum medication in the studied eye
• History of vitreoretinal surgery for a condition other than the idiopathic macular hole (retinal detachment, vitreous hemorrhage)
• History of retinal detachment of any etiology
• A patient who manifests himself not being able to perform the head position in the postoperative period
• A patient with active anterior or posterior uveitis