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Abstract
Purpose
To report 2 cases of far-advanced keratoconus with a high value of maximum keratometry and very thin corneas treated with corneal crosslinking (CXL).
Case summary
The thinnest corneal thickness of an 18-year-old woman with maximum keratometry of 106.5 D (case 1) was 335 µm. The thinnest corneal thickness of a 43-year-old man with maximum keratometry of 120.3 D (case 2) was 345 µm. The two cases underwent a customized topography and pachymetry-guided epithelial debridement technique to preserve the epithelium where the cornea was within 2 mm around the cone and subsequent CXL. Postoperative maximum keratometry was 97.2 D 24 months after CXL in case 1 and 109.3 D 18 months after CXL in case 2. Postoperatively, the thinnest corneal thickness was 343 µm in case 1 and 162 µm in case 2. The corneal thickness in case 1 was stabilized during the follow-up examination. The pupil center and apex of the corneal thickness in case 2 with the higher maximum keratometry was stabilized, but the thinnest corneal thickness was decreased immediately after CXL and did not recover before CXL.
Conclusions
CXL was performed in 2 cases of far-advanced keratoconus. Results showed reduced maximum keratometry but, variable values in corneal thickness during the follow-up examination in the 2 cases. Longer follow-up is necessary, and CXL should be performed cautiously, especially for patients with far-advanced keratoconus.
Figures and Tables
Figure 1
Anterior segment photography of the left eye in case 1 showing the apex of the cone (white arrow) in the inferior paracentral cornea and anterior stromal scars (white arrow head) within the cone at initial visit.
Figure 2
Corneal topography of the left cornea in case 1. (A) shows the central cornea with high maximum K (Kmax) values of 106.5 D and mean K (Kmean) of 74.1 D at initial visit. (B) shows Kmax of 97.2 D and Kmean of 72.2 D 24 months after CXL. (C) shows corneal thickness at the pupil center (CCT) of 347 µm, corneal thickness at the apex (CTapex) of 351 µm and corneal thickness at the thinnest point (CTthin) of 335 µm. The outer circle was placed at the 9 mm corneal zone and the area of the cornea within the inner gray line was placed under 400 µm of corneal thickness at initial visit. (D) shows CCT of 387 µm, CTapex of 361 µm, and CTthin of 343 µm 24 months after CXL.
Figure 3
Anterior segment photography of the left eye in case 2 showing the apex of the cone (white arrow) in the inferior paracentral cornea and anterior stromal scars (white arrow head) lateral to the cone at initial visit.
Figure 4
Corneal topography of the left cornea in case 2. (A) shows Kmax of 120.3 D and Kmean of 82.7 D at initial visit. (B) shows Kmax of 109.3 D and Kmean of 80.1 D 18 months after CXL. (C) shows CCT of 459 µm, CTapex of 403 µm, and CTthin of 345 µm, the outer circle was placed at the 9 mm corneal zone and the area of cornea within the inner gray line was placed under 400 µm of corneal thickness at initial visit. (D) shows CCT of 452 µm, CTapex of 403 µm, and CTthin of 162 µm 18 months after CXL.
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