Optical Coherence Tomography in Gas-filled Eyes
Condition: Macular Hole
MeSH terms: Retinal Perforations
Study type: Observational

Summary: 
      The aim of this study is to determine the condition to detect the status of a macular hole by
      spectral domain optical coherence tomography (SD-OCT) in gas-filled eyes. The macular area is
      scanned by SD-OCT (OCT-4000, Carl Zeiss Meditec) in the patients who underwent vitreous
      surgery for macular hole to detect macular jole closure on postoperative days 1, 3, 7, and
      30.
    

Detailed description: 
      We studied 26 eyes with an idiopathic macular hole (MH), 7 eyes with a MH retinal detachment
      (MHRD), and 4 eyes with a MH with myopic traction maculopathy. This was a prospective study
      conducted between April 2009 and August 2009 at the Kyorin Eye Center of the Kyorin
      University School of Medicine, Tokyo, Japan. The age, gender, laterality of the diseased eye,
      stage of MH based on the Gass classification, and Snellen best-corrected visual acuity (BCVA)
      were recorded. The axial length was measured with the OA1000 (TOMEY Corp., Nagoya, Japan)
      preoperatively in eyes with MH and postoperatively in eyes with MHRD and myopic traction
      maculopathy to avoid the effect of retinal detachment on the axial length. The presence of a
      posterior staphyloma within the posterior vascular arcade was determined by ophthalmoscopy
      and ultrasonography (Ultrascan®, Alcon Laboratories, Fort Worth, TX).

      Standard pars plana vitrectomy was performed. The internal limiting membrane (ILM) was
      removed after making it visible with triamcinolone acetonide (Kenacort-A®, Bristol
      Pharmaceuticals KK, Tokyo, Japan) or indocyanine green (Santen Pharmacy, Osaka, Japan) in all
      eyes. Preoperative cataracts were graded as mild (nuclear sclerosis 1+) or moderate to
      advanced (nuclear sclerosis 2+ or 3+), and phacoemulsification with implantation of an
      intraocular lens was performed on all cataractous eyes higher than grade 1. Room air, 20%
      sulfur hexafluoride (SF6), or 14% perfluoropropane (C3F8) was used to tamponade the retina.
      When the MH was confirmed to be closed in the patients with a idiopathic MH, the face-down
      position was discontinued although the patients were instructed to avoid an upright position.
      Patients with MHRD and myopic traction maculopathy were instructed to keep a facedown
      position for one to two weeks even after a MH closure was detected.

      All surgery was performed under retrobulbar anesthesia, and a written informed consent was
      obtained from all patients after a full explanation of the purpose and possible complications
      of the treatment. The study protocol was approved by the Institutional Review Committee of
      the Kyorin University School of Medicine and all of the patients approved the clinical review
      of their medical records.

      The entire macular area was scanned by SD-OCT (OCT4000, Cirrus HD-OCT, Carl Zeiss Medic Inc.,
      Dublin, California, USA) in the sitting position to avoid missing a MH. The 5-line raster
      mode was used to obtain high quality images on postoperative days 1, 3, 7, and 30. When a
      macular image could not be obtained, the patients were instructed to look slightly downward
      or upward until a clearer view of the macular area was obtained in the OCT images. The
      ability to detect a closed MH or the status of the foveal detachment or schisis by the SD-OCT
      was evaluated, and the pre- and postoperative factors that affected the OCT images were
      investigated. The volume of intravitreal gas was estimated by the level of the inferior gas
      meniscus at the retina with an indirect ophthalmoscope in a sitting position.
    

Intervention name(s): Vitreous surgery
Intervention type(s): Procedure
Intervention description(s): Vitreous surgery is performed to treat the original disease not for the study.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The patients who had a vitreous surgery for macular hole, macular hole retinal detachment,
        myopic traction maculopathy and examined spectral domain optical coherence tomography
        preoperatively and postoperatively.
      
Keywords: gas tamponade,; macular hole,; macular hole retinal detachment,; optical coherence tomography