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, as a result providing better and greater corneal surface regularisation and refractive correction.

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

Intracorneal Implants - Kerarings

Intracorneal Implants - Kerarings

Features and Benefits

Kerarings - Variable Optical Zones

Variable Optical Zones

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

Kerarings - Variable Arc Lengths

Variable Arc Lengths and Thicknesses

Keraring offers 40 different variations of thicknesses, arc lengths and diameters, which allows for enhanced customisation of corneal remodeling and refractive correction.

Kerarings - Unique Prismatic Design

Unique Prismatic Design

Keraring’s design generates a prismatic effect by which the light coming through the implant is reflected, consequently 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. Above all, independent clinical trails have confirmed Keraring’s safety and effectiveness.


Keraring may be explanted at any time, which allows 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 Transplantion

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. Most noteworthy is that, topographic and refractional changes are noticeable right after implantation and stabilise in 3 months on average.

Surgical Technique and Training

Keraring implantation is a simple outpatient procedure performed under topical anesthesia. For this reason, Mediphacos has developed surgical instruments specifically for manual and femtosecond laser assisted techniques. Furthermore, Keraring surgeons must attend one of the certification courses regularly offered by Mediphacos and its authorised distributors. Please contact us for current program schedules or to request training in your own practice.

Nomograms and Consultancy

Keraring surgical outcomes greatly depend on accurate selection of implant size and position for each individual patient. Based on extensive statistical analysis of results, Mediphacos constantly updates the calculation nomograms and provides surgeons with personal attention and highly reliable expert support.

  • Keratoconus with poor BSCVA and contact lens intolerance
  • 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
Mechanisms 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 stabilisation, delaying or eliminating the need for corneal transplantation