Intracorneal Ring Segments By

Femtosecond Tunnel Creation

BY Dr. Amr Mounir Lecturer of ophthalmologySohag university

Keratoconus is a progressive, noninflammatory, bilateral (but usually asymmetric) ectatic corneal disease.

Introduction

Treatment modalities include hard contact lens, corneal collagen crosslinking, Intracorneal ring segments and Keratoplasty

Intracorneal Rings

Mechanism of action of rings

Types of Rings

Methods of implantation of rings

- Precise Depth - Precise Incision site creation- Easier than manual - Avoid complications of manual tunnel creation

e,g: Anterior or Posterior corneal perforations , epithelial defects, infectious keratitis, asymmetric segment placement, corneal stromal oedema around the incision, extension of the incision towards the central visual axis or the limbus and persistent incisional gapping

Advantages of Femtosecond Tunnel Creation

High errors.Mean Keratometry > 48 DsK Max > 50 DsBCVA < 6/30 High patient motivation

Ideal patient for rings

Our provisional Experiencein Sohag

Rings we use

Parameters which guide us

- Refraction- Pachymetry - Steepest K axis - Cone site - Nomogram

Non central cones.High cylinder.High difference between K1, K2.Thickness at insertion site >400

um

Kerarings

Non of treatment options is satisfactory for the patient.

The disease is progressive by its nature.Follow up is mandatory.Combination of treatment options can be done.Keratoplasty can be a final destiny even with

treatment.Rings mostly will be followed by glasses.Don't judge on improvement of V\A without correction.Financial aspect should be taken into consideration.Rings results are unpredictable

Rules in treatment by rings

Nomogram for Kerarings

Tunnel creation by Femtosecond laser

Kerarings Ring implantation

Pre and post Kerarings Pentacam

About 250 eyes had been operated with Keraringes implantation by Intralase technology

Our provisional experience in Sohag Femtocenter

We ask ourselves very important question

What are factors that affect the results of ring

implantation ????

Age as a guideline

A 23 ys female with bil. Keratoconus Rt. Eye is advanced more than Lt. eye.

Preoperative refraction of Rt. eye : -6.00 Ds -3.50 Dc

UNCVA : 4/60BCVA : 6/30

Postoperative refraction of Rt. eye : -2.50 Ds -1.50 Dc

UNCVA : 6/30BCVA : 6/18

Symmetry of Bowtie as a guideline

A 37 ys male with bil. Keratoconus Rt. Eye is advanced more than Lt. eye.

Preoperative refraction of Rt. eye : -4.25 Ds -7.00 Dc

UNCVA : 3/60BCVA : 6/38

Postoperative refraction of Rt. eye : +1.00 Ds -1.0 Dc

UNCVA : 6/38BCVA : 6/18

Corneal thickness as a guideline

A 17 ys male with RT. Advanced Keratoconus .

with thinnest location 348 um with max k: 60 D Preoperative refraction of Rt. eye : -15.00 Ds -8.00 Dc

UNCVA : 2/60BCVA : 6/60

Postoperative refraction of Rt. eye : -7.50 Ds – 5.00 DcUNCVA : 6/60BCVA : 6/30

Rings in advanced cases

To delay corneal grafting.To make the eye refractable.To decrease coma aberrations.

N.B: Keratoplasty is still an option

Aim:

Thank you