In the selection of the candidates, special attention should be paid the anterior chamber depth and to iris shape. Patients with shallow anterior chamber and/or convex iris should be excluded.

During surgery, the key points to have perfect surgery are avoiding trauma and putting sufÞcient amount of iris tissue grasped by the haptics.

(c)Posterior chamber IORLs:

1.Intraoperative complications: Most intraoperative complications are rare and almost always related to human errors. The most important complication is trauma to the crystalline lens, which may or may not manifest later.

2.Early postoperative complications:

¥Pupillary block glaucoma due to the blockage of previous laser iridotomies or viscoelastic material residue in the posterior chamber. It shows itself within the Þrst 24Ð48 h.

¥Loss of BSCVA

¥Overcorrection and under correction.

¥Quality of vision disturbances

¥Inßammation

¥Endophthalmitis

3.Late postoperative complications:

¥Iatrogenic anterior subcapsular cataract may develop because of contact with the natural crystalline lens. Many patients develop cataract within 2 years. This complication is size related; a small IORL has greater chances of having direct contact with the crystalline lens. Sizing should not be based on external anatomy or white-to-white distance which correlates poorly with the internal anatomy; thus, sizing should be done by UBM and then calculated by accomplished software.

¥Uveitis may occur in acute or chronic form.

¥Pigment dispersion may be seen on the artiÞcial lens or the natural lens.

¥Late glaucoma may occur because of crowding of the angle and pigment deposits in the angle.

¥In some cases, the pupil may become partially dilated and not responding to the usual miotics.

¥Corneal decompensation.

¥Vitreoretinal complications such as progressive posterior retinal atrophy, spontaneous

or neovascular macular hemorrhage, and rhegmatogenous retinal detachment.

¥Zonular damage, decentration, anterior and posterior dislocation.

3.2.3Combination Between Treatment Modalities

It is not unusual that a KC case can be (or needs to be) treated with more than one treatment modality as shown in many studies. For example, a progressive case with high refractive error and good BSCVA can be treated by CxL to stabilize the cornea and IORLs to correct the high refractive error. A second example, a progressive moderate KC with moderate refractive error can be treated either by CxL and contact lenses if the patient is tolerant, or by CxL and spectacles, or by CxL and ICRs. A third example, a stable case of moderate KC with very high refractive error but with good BSCVA can be treated by ICRs then by IORLs in a second stage. In other words, combination between treatment modalities gives the opportunity to correct as much as possible corneal irregularity and refractive error, but with the least number of procedures.

3.3Management Parameters

3.3.1Introduction

Before starting discussion of management parameters, there are general considerations regarding full evaluation of the patient:

¥Using RGP lenses must be stopped for at least 2 weeks before evaluation of any KC case to achieve a correct measurement of the corneal shape.

¥Anecdotally reported refractive changes do not serve as a basis for decision making.

¥Measurements previously performed in other clinics cannot be a basis for a treatment decision but can give an idea of the progression of the disease.

¥Corneal topography should be done with Scheimpßug imaging and it will be more accurate when combined with Placido imaging system.

¥Progression of the ectasia can only be determined by follow-ups.

¥Family history should be considered.