Measuring higher order optical aberrations of the human eye: techniques and applications
| Autor: | J.C. Castro, L. Alberto V. Carvalho, L. Antonio V. Carvalho |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Physiology
Zernike polynomials medicine.medical_treatment Optical instrument Immunology Biophysics Coma (optics) Astigmatism Optical aberrations Biochemistry law.invention symbols.namesake Optics law Refractive surgery Image Processing Computer-Assisted medicine Humans General Pharmacology Toxicology and Pharmaceutics lcsh:QH301-705.5 Physics lcsh:R5-920 Models Statistical Eye Artificial business.industry General Neuroscience Cell Biology General Medicine Refractive Errors medicine.disease Aberrations of the eye Spherical aberration medicine.anatomical_structure lcsh:Biology (General) symbols Human eye Corneal topography lcsh:Medicine (General) business Mathematics |
| Zdroj: | Brazilian Journal of Medical and Biological Research, Vol 35, Iss 11, Pp 1395-1406 (2002) Brazilian Journal of Medical and Biological Research v.35 n.11 2002 Brazilian Journal of Medical and Biological Research Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC Brazilian Journal of Medical and Biological Research, Volume: 35, Issue: 11, Pages: 1395-1406, Published: NOV 2002 |
| ISSN: | 0100-879X |
| Popis: | In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia) and higher order aberrations (coma, spherical aberration, etc.). We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45 degrees and 90 degrees. We used a device known as the Hartmann-Shack (HS) sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE) of less than 0.1 micro m for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5 degrees for the axis. This precision is sufficient for customized corneal ablations, among other applications. |
| Databáze: | OpenAIRE |
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