Intacs for Keratoconus

2014-07-23 21:43:17 | BioPortfolio


To study the effects Intacs intracorneal ring segments(Addition Technology, Inc) insertion in the treatment of keratoconus


The purpose of this evaluation is to study the effects of implanting INTACS inserts, identical to those commercially available to correct myopia, into the corneal stroma of patients with keratoconus (mild to moderate) and having a clear cornea. The principle of the procedure is to flatten the cornea deformed by keratoconus. One or two segments of the same or a different thickness will be selected to reduce the asymmetric astigmatism responsible for the patient impaired visual acuity.

The surgical technique is based on locating the INTACS inserts on the flattest axis of the refractive error, making the incision on the steepest axis, using 150 degree arc length inserts with different sizes (0.250, 0.300, 0.350, 0.400 & 0.450 mm) according to a nomogram designed for this technique using the INTACS Instrumentation (10-Step Prolate System instruments).

The corneal lamellar channel creation may be performed using the INTACS instrumentation or using the Femtosecond laser (Femtec 20/10 laser[Femtec,Heidelberg Germany])

Primary Assessment Criteria

- Evaluation of the safety of the device for the treatment of patients with keratoconus (mild to moderate)

- Maintenance of best corrected visual acuity (BCVA)

- Improvement in uncorrected visual acuity (UCVA)

- Reduction in manifest refraction spherical equivalent

- Reduction in asymmetric astigmatism

Secondary Assessment Criteria

- Evaluation of the effect of INTACS inserts placement for treatment of corneal ectasia

- Determination of patient satisfaction following the INTACS inserts procedure Patients meeting the eligibility criteria are required to sign a Patient Informed Consent Form prior to study participation.

A thorough examination is perform to evaluate the following:

- Manifest refraction results - Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA)

- Cycloplegic refraction results - Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA)

- Corneal topography

- Pachymetry

- Step axis location

- Location of incision placement

- Subjective feedback about quality of vision (Excellent, Good, Fair and Poor)

Post-operative Assessment(at 1 day, 1 week, 1 month and 3 months postop)

- Uncorrected visual acuity (UCVA) and best corrected visual acuity with manifest refraction(BCVA) at designated time interval

- Cycloplegic refraction results - Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) at designated time interval

- Corneal topography at designated time interval

- Pachymetry at designated time interval

- Subjective visual outcome ratings over time (Excellent, Good, Fair and Poor)

- Report adverse events

Study Design

Allocation: Non-Randomized, Control: Uncontrolled, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment




Intacs intracorneal ring insertion for the treatment of keratoconus


Singapore National Eye Centre




Singapore National Eye Centre

Results (where available)

View Results


Published on BioPortfolio: 2014-07-23T21:43:17-0400

Clinical Trials [464 Associated Clinical Trials listed on BioPortfolio]

INTACS (Intrastromal Corneal Ring Segments) For Corneal Ectasia

To join established study put on by Addition Technologies, Inc. in the surgical implantation of asymmetrical INTACS segments to treat myopia and astigmatism in patients with keratoconus.

Management of Patients With Keratoconus With Intacs

Purpose To evaluate long-term follow up of Intacs microthin prescription inserts (Addition Technology Inc, Fremont, Calif) for the management of keratoconus. Design A long-term (five year...

Collagen Cross-Linking for Keratoconus/Ectasia With and Without Intacs

This study will determine the efficacy of collagen cross linking for progressive keratoconus and ectasia after lasik. It will try and determine which is a more effective treatment: collage...

MyoRing Implantation With Corneal Collagen Crosslinking for Keratoconus

A complete intrastromal ring, MyoRing (Dioptex, GmbH, Linz, Austria), suggested by Albert Daxer in 2007, is a relatively new technique that has been demonstrated to treat keratoconus safel...

Objective and Subjective Diagnostic Parameters in the Fellow Eye of Unilateral Keratoconus

patients with keratoconus in one eye and forme fruste keratoconus in the fellow eye compared to normal subjects .the patients were examined by schemipflug imaging system (Pentacam)

PubMed Articles [18096 Associated PubMed Articles listed on BioPortfolio]

Effects of Preoperative Topometric Indices on Visual Gain After Intracorneal Ring Segment Implantation For Keratoconus.

To assess the corneal topometric parameters that can be predictive for better visual gain after intracorneal ring segment (ICRS) implantation in eyes with keratoconus.

Anterior Corneal Curvature and Aberration Changes After Scleral Lens Wear in Keratoconus Patients With and Without Ring Segments.

To evaluate changes in the anterior corneal curvature and aberrometry after scleral contact lens wear in keratoconus (KC) subjects with and without intracorneal ring segments (ICRS).

Computational Models for Optimization of the Intrastromal Corneal Ring Choice in Patients With Keratoconus Using Corneal Tomography Data.

To evaluate the predictability of asphericity and average keratometry in patients with keratoconus after implantation of intrastromal corneal ring segments (ICRS) using artificial intelligence.

Corneal Biomechanics in Unilateral Keratoconus and Fellow Eyes with a Scheimpflug-based Tonometer.

Before the appearance of evident keratoconus, corneal biomechanical changes may be detectable. Here, these properties are analyzed to detect any difference that could help in the early recognition of ...

Macular and Peripapillary Choroidal Thickness in Patients With Keratoconus.

To investigate and compare macular and peripapillary choroidal thickness and profiles of patients with keratoconus and age-matched controls and correlate subfoveal choroidal thickness with keratoconus...

Medical and Biotech [MESH] Definitions

A noninflammatory, usually bilateral protrusion of the cornea, the apex being displaced downward and nasally. It occurs most commonly in females at about puberty. The cause is unknown but hereditary factors may play a role. The -conus refers to the cone shape of the corneal protrusion. (From Dorland, 27th ed)

The measurement of curvature and shape of the anterior surface of the cornea using techniques such as keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing and videokeratography. This measurement is often applied in the fitting of contact lenses and in diagnosing corneal diseases or corneal changes including keratoconus, which occur after keratotomy and keratoplasty.

A mutation named with the blend of insertion and deletion. It refers to a length difference between two ALLELES where it is unknowable if the difference was originally caused by a SEQUENCE INSERTION or by a SEQUENCE DELETION. If the number of nucleotides in the insertion/deletion is not divisible by three, and it occurs in a protein coding region, it is also a FRAMESHIFT MUTATION.

Surgical insertion of cylindric hydraulic devices for the treatment of organic ERECTILE DYSFUNCTION.

A group of two-ring heterocyclic compounds consisting of a benzene ring fused to a diazepine ring.

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