Case 7

A 16-year-old male patient is complaining of progressive deterioration of vision, and recently, he has been diagnosed to have bilateral KC. He has not been treated yet and does not use spectacles.

His MR is (Table 4.7.1):

Table 4.7.1 Manifest refraction

Slitlamp examination shows clear corneas with no stress lines. Other ocular examination is within normal limits.

Figure 4.7.1 is corneal topography of the right eye. Figure 4.7.2 is the anterior curvature map after color modification.

Figure 4.7.3 is corneal topography of the left eye. Figure 4.7.4 is the anterior curvature map after color modification.

1. The patient is very young; he is 16 years old. KC is supposed to be progressive in this age.

2. UCVA and BSCVA are very good and it seems to be a simple refractive error rather than KC.

3.Both corneas are clear with no stress lines.

4.Corneal topography.

(a)Right eye:

•Figure 4.7.1 is corneal topography of the right eye. Corneal thickness at the thinnest location is 489 m, the maximal K-reading is 48.7 dpt, and the Km is 45.7 dpt.

•Figure 4.7.2 is the anterior curvature map. It is either PMD or PLK, but when considering other maps, it is PLK. This case is pattern 5 according to the author’s classification.

•According to Krumeich, it can be considered as grade 2.

Fig. 4.7.4 Anterior curvature map of the left eye. The curvature pattern is round hot spot IS. According to author’s classification, it is pattern 7

(b)Left eye:

•Figure 4.7.3 is corneal topography of the left eye. Corneal thickness at the thinnest location is 449 m, the maximal K-reading is 59.5 dpt, and the Km is 51.6 dpt.

•Figure 4.7.4 is the anterior curvature map. The cone is eccentric and according to the author’s classification, it is pattern 7.

•According to Krumeich, it can be considered as grade 2.

4.7.2Step 2: Management Suggestions

Table 4.7.2 summarizes patient data and the corresponding individual suggestion(s) for treatment, and presents with a final summary of the best management.

4.7.3Step 3: Discussion Step

The patient is 16-year-old and his case is progressive, yielding the need for CxL.

ICRs are not suitable for this case due to the following reasons:

1.The manifest refractive error is very small especially astigmatism.

2.The topographical astigmatism is not reasonable enough to indicate implanting ICRs. It is noticed

that the left eye is more advanced than the right eye although the topographical astigmatism is smaller in the left eye. That is because the cone in the left eye is more eccentric than that in the right eye.

3.Implanting rings usually pushes the cone toward the center of the cornea leading – in such a case – to increase in both spherical and astigmatic components of the refractive error!

PRK and CxL may be suitable to regularize the cen-

tral 5 mm of the cornea and therefore improve the

quality of vision. This is possible because of the suitable thickness, but it is to remember that 40 m of maximal ablation depth is an important issue and the priority is for the irregular astigmatism.

What are suitable also are glasses after CxL. That is probably the most logic choice since the refractive error is so small and both UCVA and BSCVA are very good. The patient has not tried the spectacles yet, so it is appropriate to persuade him to have CxL and continue with glasses.