Hipermetropia após ceratotomia radial: flutuação da refração e da acuidade visual entre manhã e tarde e correlações com a pressão ocular e o estado biomecânico da córnea

Hipermetropia após ceratotomia radial: flutuação da refração e da acuidade visual entre manhã e tarde e correlações com a pressão ocular e o estado biomecânico da córnea

Alternative title Hyperopia after radial keratotomy: fluctuation of refraction and visual acuity from morning to evening and correlations with intraocular pressure and corneal biomechanics
Author Ambrósio, Renato Autor UNIFESP Google Scholar
Silva, Renata Siqueira da Google Scholar
Lopes, Karla Google Scholar
Valbon, Bruno Google Scholar
Luz, Allan Autor UNIFESP Google Scholar
Velarde, Guillermo Coca Google Scholar
Institution Cornea Rio de Janeiro
Universidade Federal de São Paulo (UNIFESP)
Universidade Federal Fluminense (UFF)
Abstract Purpose: To verify the morning to evening variations of refraction, visual acuity, intraocular pressure and biomechanical parameters on patients operated by radial keratotomy who presented for refractive re-treatments; and to correlate the biomechanical parameters with refraction, visual acuity and their variations among morning and evening. Methods: 19 patients were examined, respectively thirty-eight eyes in the morning (9 am) and evening (6 pm), recording sphere-cylindrical dynamic refraction, visual acuity (logMAR) without correction (AVsc) and corrected (AVcc) and ORA (Ocular Response Analyzer) parameters: corneal hysteresis (CH), corneal resistance factor (CRF), intraocular pressure calibrated for Goldmann (IOPg) e corneal compensated (IOPcc). Variables had no normal distribution (Kolmogorov-Smirnov test), so that the Wilcoxon signed rank was used for testing the significance on the differences for each variable between morning and afternoon. The Spearman test was used for assessing the correlations between the ORA parameters and refraction, visual acuity in the morning and afternoon, as well as to verify the correlations between the ORA parameters and the variations on refraction and visual acuity. Results: Sphere (E), spherical equivalent (EE), defocus equivalent (ED), AVsc, IOPcc e IOPg varied significantly (Wilcoxon, p<0.05) between morning and evening. There was more hyperopia, worse visual acuity, higher pressure and lower CH in the morning measurements. In the morning measurements, there was a positive correlation (Spearman, p<0.05) between EE and ED and IOPcc (rs=0.39 and 0.34 respectively), but not with IOPg. In the evening measurement, there were no correlations between the refractive and pressure measurements. Negative correlations were observed (Spearman, p<0.05) between AVsc (logMAR) and CH in the morning and in the evening (rs=-0.48 e rs=-0,51), between E and CH in the morning and in the evening (rs=-0.66 and -0.76), between E and CRF in the morning and in the evening (rs=-0.40 and -0.47), between EE and CH in the morning and in the evening (rs=-0.70 and -0.68), between EE and CRF in the morning and in the evening (rs=-0.41 and -0.46), between ED and CH in the morning and in the evening (rs=-0.64 and -0.54) and between ED and CRF in the morning and in the evening (rs=-0.35 and -0.34). There was a significant negative correlation between the morning measurement of CRF and the variation of defocus equivalent (p = 0.05; rs = -0.30) and the variation of AVsc (p = 0.04; rs = -0.33). Conclusion: More hyperopia was recorded in the morning which was associated with higher compensated pressure (IOPcc) but not with IOPg ten years after RK. Lower biomechanical parameters (CRF e CH) were associated with higher hyperopia and worse visual acuity. A trend was observed for having higher fluctuation on weaker corneas. New studies involving the variables derived from the waveform signals, beyond CH and CRF (derived from the applanation pressures) along with data from corneal tomography and wavefront aberrometry are necessary.
Keywords Keratototmy, radial/adverse effects
Hyperopia
Cornea/physiology
Refractive erros
Visual acuity
Language Portuguese
Date 2012-05-01
Published in Revista Brasileira De Oftalmologia. Rio De Janeiro: Soc Brasileira Oftalmologia, v. 71, n. 3, p. 164-172, 2012.
ISSN 0034-7280 (Sherpa/Romeo, impact factor)
Publisher Soc Brasileira Oftalmologia
Extent 164-172
Origin http://dx.doi.org/10.1590/S0034-72802012000300005
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000310854100005
SciELO ID S0034-72802012000300005 (statistics in SciELO)
URI http://repositorio.unifesp.br/11600/45370

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