KeraRings are available at the following centres:

BMI Mount Alvernia Hospital
Manchester Royal Eye Hospital
Sheffield Royal Hallamshire Hospital

Keraring intrastromal corneal ring segments are implantable precision devices used to correct corneal surface irregularities and reduce refractive errors associated with keratoconus and other corneal ectatic disorders. Unlike other intracorneal rings, Keraring was specifically designed to treat corneal ectasia, providing better and greater corneal surface regularization and refractive correction.

Features of the KeraRings are as follows:

Variable Optical Zones

Keraring is available in two models (SI-5 and SI-6) for 5.0 mm implantation in optical zones of 5.0, 5.5 and 6.0mm, offering surgeons additional options to meet each patient’s needs.

Variable Arc Lengths and Thicknesses

Keraring offers 40 different variations of thicknesses, arc lengths and diameters, allowing for enhanced customization of corneal remodeling and refractive correction.

Unique Prismatic Design

Keraring’s design generates a prismatic effect by which the light coming through the implant is reflected, reducing the incidence of glare and halos.

Greater Refractive Correction

Keraring corrects low, moderate, and high degrees of myopia and astigmatism.

Proven Clinical Safety

Extensive track record of use and longest follow-up worldwide: over 150,000 implants followed up for as long as 18 years. Independent clinical trails have confirmed Keraring’s safety and effectiveness.


Keraring may be explanted at any time, allowing the cornea to revert to its original preoperative shape. The procedure is reversible.


Refractive and topographic results may be easily readjusted by exchanging or repositioning the implant.

Compatibility with other procedures

Keraring implants may be synergistically combined with other techniques such as corneal collagen crosslinking, PRK and phakic IOL implantation.

Does not compromise corneal transplantation

Keraring does not interfere with normal execution of lamellar or penetrating keratoplasty, if needed.

Outstanding patient satisfaction

Keraring patients report highly positive improvements in their quality of life.

Quick visual recovery

Minimally invasive technique allows patients to rapidly resume their normal activities. Topographic and refractional changes are noticeable right after implantation and stabilize in 3 months on average.


• Material: Medical Grade PMMA
• Models: SI5 (5mm optical zone). SI6 (5.5mm or 6mm optical zone)
• Variable thickness: 150μm to 350μm (all models) in 50μm increments.
• Variable arc length:
• SI-5: 90º, 120º, 160º and 210º
• SI-6: 90º, 120º, 150º and 210º
• Keraring is presented with one ring segment per box.


• Keratoconus with poor BSCVA and contact lens intolerance
• Progressing keratoconus
• Pellucid marginal degeneration
• Post Lasik ectasia
• Irregular astigmatism following radial keratotomy
• High astigmatism secondary to penetrating keratoplasty
• Post-trauma corneal irregularities


• Acute keratoconus with keratometry > 70 D
• Major central corneal opacity
• Hydrops
• Following penetrating keratoplasty when graft is decentered
• Severe atopic disease
• Recurring corneal erosion syndrome
• Patient’s high expectations to achieve emmetropia

Mechanism of Action

• Corneal remodeling through addition technique: preserves corneal integrity
• Corneal topography regularization and refractive correction preserving the natural prolate profile, reducing optical aberrations and improving visual acuity and contact lens tolerance
• Displacement of corneal apex towards the central pupil
• Corneal stabilization, delaying or eliminating the need for corneal transplantation


Your LaserVision consultant surgeon can expertly guide you through the best treatments for you. Each treatment is personalised to achieve the best results.

In association with:
Sheffield Teaching Hospital NHS Foundation Trust, Greater Manchester University Hospitals NHS Foundation Trust