Intrastromal Corneal Ring for High Astigmatism on Postkeratoplasty
Condition: Astigmatism
MeSH terms: Astigmatism
Study type: Interventional
Phase: Phase 4

Summary: 
      To evaluate the clinical outcomes of Intrastromal Corneal Ring Segment (ICRS) implantation to
      correct high-degree astigmatism on eyes with prior penetrating keratoplasty (PK).
    

Detailed description: 
      Eighteen eyes of 18 patients, 8 men and 10 women, with high levels (> 5 diopters [D]) of
      postkeratoplasty astigmatism were studied in a nonrandomized, retrospective, observational
      case series. Mean age at the time of ICRS implantation was 38 years, range 22 to 49 years. PK
      was performed to treat keratoconus in 15 patients, corneal scar after trauma in 2 patients,
      and Fuchs endothelial dystrophy in 1 patient. All patients were spectacle and contact lens
      intolerant. There was no active corneal disease or problem apart from high astigmatism.

      Minimum time of ICRS implantation was 2 years after PK and at least 6 months after sutures
      removal.

      Preoperative examinations included personal medical ocular history, uncorrected visual acuity
      (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, keratometry, intraocular
      pressure (IOP) measurement by applanation tonometry, corneal astigmatism, surface regularity
      index, surface asymmetry index, tonometry, slit-lamp biomicroscopy, specular microscopy, and
      fundus examination.

      Main outcome measures included UCVA, BSCVA, refraction, keratometry and computerized analysis
      of corneal topography.

      All surgeries were performed by the same surgeon (BAN) at the Goiania Eye Institute, between
      July 2007 and January 2009. Corneal tunnels were created by means of mechanical dissection in
      all eyes. Intrastromal corneal ring segments implantation was indicated because of the
      existence of reduced best spectacle-corrected visual acuity (BSCVA) or contact lens
      intolerance. Intracorneal ring segments implantations were performed by the same surgeon
      following the same protocol. All eyes were implanted with the Cornealring (Visiontech Medical
      Optics, Belo Horizonte, MG, Brazil). Mean follow-up after ICRS implantation was 12 months
      (range, 09 to 22 months).

      The procedure, its goals, and possible complications were explained and all patients signed
      an informed consent. The amount and axis of astigmatism to be corrected by ICRS was based on
      manifest refraction.
    

Intervention name(s): INTRASTROMAL CORNEAL RING SEGMENT
Intervention type(s): Procedure
Intervention description(s): Corneal tunnels were created by means of mechanical dissection in all eyes. Intrastromal corneal ring segments implantation was indicated because of the existence of reduced best spectacle-corrected visual acuity (BSCVA) or contact lens intolerance.
Intervention model: Single Group Assignment
Masking: Single (Investigator)
Primary purpose: Treatment
Keywords: INTRASTROMAL CORNEAL RING; ASTIGMATISM; POSTKERATOPLASTY; EYES; To evaluate the clinical outcomes of ICRS implantation to correct high-degree astigmatism on eyes with prior penetrating keratoplasty (PK)