Intrastromal Corneal Ring for High Astigmatism on Postkeratoplasty

Study Overview
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Brief Summary
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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
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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.

Official Title
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Intrastromal Corneal Ring Segment Implantation for High Astigmatism on Postkeratoplasty Eyes

Conditions
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Astigmatism

Intervention / Treatment
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* Procedure: INTRASTROMAL CORNEAL RING SEGMENT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: > 5 diopters of postkeratoplasty astigmatism Patients 21 to 50 years old Conventional treatments have failed Exclusion Criteria: Diabetes Autoimmune diseases

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: INTRASTROMAL CORNEAL RING SEGMENT<br>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. PK was performed to treat keratoconus in 15 patients, corneal scar after trauma in 2 patients, and Fuchs endothelial dystrophy in 1 patient. | Procedure: INTRASTROMAL CORNEAL RING SEGMENT<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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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)