Ortega DL, Carralero RYL, Hernández SJR, Rodríguez SS, Riverón RY, Massip NJ

Language: Spanish
References: 19
Page: 427-438
PDF size: 218.15 Kb.

ABSTRACT

Objective: to describe the characteristics of the posterior corneal surface in normal corneas and its changes in patients who underwent laser in situ keratomileusis.
Methods: prospective, longitudinal and descriptive study of 282 eyes from patients who went to the refractive surgery service. The studied variables were posterior central mean keratomery, spheral equivalent, optical pakimetry at the thinnest position, anterior and posterior topographic astigmatism, refractive astigmatism and morphological variation of the posterior elevation topographic map in relation to the best fit sphere. In this group, 27 eyes were selected, which met the criteria for laser refractive surgery using the laser in situ keratomileusis. Other analyzed variables were ablation amount, residual stroma and posterior corneal elevation difference, being the latter taken from the difference map outlined with the Pentacam HR tomography.
Results: mean posterior keratometry was -6,37 ± 0,22 dioptries; the correlation between mean posterior keratometry and optical pakimetry was very significant (p= 0,008). The mean difference of maximum elevation with respect to the best posterior fit sphere was 5,33 µm; 93,3 % of the sample was within the normal values. The correlation between the posterior elevation and the spheral equivalent was also significant (p= 0,019). The difference of the posterior elevation throughout the period was 18,38 µm ± 7,47 after a month and 14,95 µm ± 10,02 at the end of the period. There was correlation with pakimetry and residual stroma.
Conclusions: laser in situ keratomileusis causes changes in the posterior corneal surface. The residual stroma is the factor most related with these changes.

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