Optical wavefront science is the photophysical description of optical perfection or imperfection. Understanding the principles of optical wavefront is essential for understanding its application, especially in customized laser vision correction (CLVC). The principal of wavefront measurement is the difference (deviation) between the actual wavefront shape of the measured surface and the ideal flat shape. This deviation is known as a wavefront aberration.
There are three types of aberrations: constant, lower order (LOAs) and higher order aberrations (HOAs). The constant aberrations exist in all optical systems. The LOAs are encountered with sphero-cylindrical refractive errors. HOAs are found in irregular optical systems.
Aberrations are measured by corneal and whole-eye wavefront aberrometers. There are three types of aberrometers: outgoing reflective, ingoing reflective and ingoing feedback aberrometers. There are several factors affecting the measurements, such as pupil size, accommodation, age, ocular pathologies and previous ocular surgeries. Aberrations can be measured at the pupillary level or at the retinal level. The root mean square (RMS) is the most common metric to quantify aberrations. There are other metrics that describe aberrations, such as point spread function (PSF), Strehl Ratio (SR), Modulation Transfer Function (MTF), Phase transfer function (PTF), optical transfer function (OTF), Zernike coefficient and Fourier Analysis. The last two are the most commonly used, and each of them has its advantages.
In addition to qualification and quantification of aberrations, there are several clinical applications of wavefront technology. It is applied in the prediction of subjective refraction, detection of forme fruste keratoconus, wavefront optimized and wavefront guided laser ablation profiles, intraocular lens design and presbyopia treatment.
As wavefront technology is applied in treatment, there are preoperative and intraoperative key factors required to achieve the desired results. The preoperative factors are wavefront capture, which must be valid, repeatable, and reproducible, precise manifest refraction, pupillometry, skillful data analysis, laser profile creation and patient counseling. The intraoperative factors are alignment and registration, centration, eye tracking, nomogram adjustment, flap creation and treatment zone.
Wavefront Aberrations Point spread function PSF Strehl ratio SR Modulation transfer function MTF Phase transfer function PTF Optical transfer function OTF Zernike coefficient and Fourier analysis Root mean square RMS
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Hofer H, Artal P, Singer B, et al. Dynamics of the human eye wave aberration. J Opt Soc Am A. 2001;18(3):497–506.CrossRefGoogle Scholar
Lombardo M, Lombardo G. Wave aberration of human eyes and new descriptors of image optical quality and visual performance. J Cataract Refract Surg. 2010;36(2):313–31.CrossRefPubMedGoogle Scholar
Artal P, Guirao A. Contributions of the cornea and the lens to the aberrations of the human eye. Opt Lett. 1998;23(21):1713–5.CrossRefPubMedGoogle Scholar
Artal P, Berrio E, Guirao A, et al. Contribution of the cornea and internal surfaces to the change of ocular aberrations with age. J Opt Soc Am A Opt Image Sci Vis. 2002;19(1):137–43.CrossRefPubMedGoogle Scholar
Atchison D, Collins M, Wildsoet C, et al. Measurement of monochromatic aberrations of human eyes as a function of accommodation by the Howland aberroscope technique. Vis Res. 1995;35(3):313–23.CrossRefPubMedGoogle Scholar
Atchinson DA, Smith G. Schematic eyes. In: Atchinson DA, Smith G, editors. Optics of the human eye. London: Butterworth-Heinemann; 2000. Appendix 3.6.Google Scholar
Barbero S, Marcos S, Merayo-Lloves JM. Total and corneal aberrations in an unilateral aphakic subject. J Cataract Refract Surg. 2002;28:1594–600.CrossRefPubMedGoogle Scholar
Born M, Wolf E. Principles of optics. 6th ed. Oxford: Pergamon Press; 1993. p. 8.Google Scholar
Castejon-Mochon FJ, Lopez-Gil N, Benito A, et al. Ocular wave-front aberration statistics in a normal young population. Vis Res. 2002;42(13):926–36.Google Scholar
Charman WN, Jennings JAM. Objective measurements of the longitudinal chromatic aberration of the human eye. Vis Res. 1976;16(9):999–1005.CrossRefPubMedGoogle Scholar
Mahajan VN. Zernike circle polynomials and optical aberrations of systems with circular pupil. Appl Opt. 1994;33(34):8121–4.CrossRefPubMedGoogle Scholar
Marcos S, Burns SA. On the symmetry between eyes of wavefront aberration and cone directionality. Vis Res. 2000;40(18):2437–47.CrossRefPubMedGoogle Scholar
Oliveira CM, Ferreira A, Franco S. Wavefront analysis and Zernike polynomial decomposition for evaluation of corneal optical quality. J Cataract Refract Surg. 2012;38(2):343–56.CrossRefPubMedGoogle Scholar
Charman WN. The optics of the eye. In: Bass M, editor. Handbook of optics. 2nd ed. New York (NY): Mcgraw-Hill; 1995.Google Scholar
Mclellan JS, Marcos S, Prieto PM, et al. Imperfect optics may be the eye's defence against chromatic blur. Nature. 2002;17:696–9.Google Scholar
Mclellan J, Marcos S, Burns S. Age related changes in monochromatic wave aberrations in human eyes. Invest Ophalmol Vis Sci. 2001;42(6):1390–5.Google Scholar
Applegate RA, Thibos LN, Hilmantel G. Optics of aberroscopy and super vision. J Cataract Refract Surg. 2001;27(7):1093–107.CrossRefPubMedGoogle Scholar
Atchison DA, Scott DH, Charman WN. Measuring ocular aberrations in the peripheral visual field using Hartmann-Shack aberrometry. J Opt Soc Am A Opt Image Sci Vis. 2007;24(9):2963–73.CrossRefPubMedGoogle Scholar
Cerviño A, Hosking SL, Montes-Mico R, et al. Clinical ocular wavefront analyzers. J Refract Surg. 2007;23(6):603–16.PubMedGoogle Scholar
Diaz-Douton F, Benito A, Pujol J. Comparison of the retinal image quality with a Hartmann-Shack wavefront sensor and a double-pass instrument. Invest Ophthalmol Vis Sci. 2004;47(4):1710–6.CrossRefGoogle Scholar
Molebny VV, Panagopoulou SI, Molebny SV, et al. Principles of ray tracing aberrometry. J Refract Surg. 2000;16(5):S572–5.PubMedGoogle Scholar
Mrochen M, Kaemmerer M, Mierdel P, et al. Principles of Tscherning aberrometry. J Refract Surg. 2000;16(5):S570–1.PubMedGoogle Scholar
Rozema JJ, Van Dyck DE, Tassignon MJ. Clinical comparison of 6 aberrometers. Part 2: statistical comparison in a test group. J Cataract Refract Surg. 2006;32(1):33–44.CrossRefPubMedGoogle Scholar
Warden L, Liu Y, Binder PS, et al. Performance of a new binocular wavefront aberrometer based on a self-imaging diffractive sensor. J Refract Surg. 2008;24(2):188–96.PubMedGoogle Scholar
Neville TM. Eye aberrations: overview. In: Pinelli R, editor. Wavefront: a text and atlas. New Delhi: Jaypee Brothers Medical Publishers; 2014. p. 29.Google Scholar
Saiki K, Negishi K, Ohnuma H, et al. Effect of change in higher order aberrations with accommodation on visual function in normal and post–Lasik. Invest Ophthalmol Vis Sci. 2006;47(13):55.Google Scholar
Zhou X-Y, Wang L, Zhou X-T, et al. Wavefront aberration changes caused by a gradient of increasing accommodation stimuli. Eye. 2015;29(1):115–21.CrossRefPubMedGoogle Scholar
Klyce SD, Karon MD, Smolek MK. Advantages and disadvantages of the Zernike expansion for representing wave aberration of the normal and aberrated eye. J Refract Surg. 2004;20(5):S537–41.PubMedGoogle Scholar
Buhren J, Kuhne C, Kohnen T. Defining subclinical keratoconus using corneal first-surface higher-order aberrations. Am J Ophthalmol. 2007;143(3):381–9.CrossRefPubMedGoogle Scholar
Buhren J, Kuhne C, Kohnen T. Wavefront analysis for the diagnosis of subclinical keratoconus (in German). Ophthalmologe. 2006;103:783–90.CrossRefPubMedGoogle Scholar
Gobbe M, Guillon M. Corneal wavefront aberration measurements to detect keratoconus patients. Cont Lens Anterior Eye. 2005;28(2):57–66.CrossRefPubMedGoogle Scholar
Saad A, Gatinel D. Evaluation of total and corneal wavefront high order aberrations for the detection of Forme Fruste keratoconus. Invest Ophthalmol Vis Sci. 2012;23(6):2978–92.CrossRefGoogle Scholar
Skuta GL, Cantor LB, Weiss JS. Refractive surgery. In:American Academy of Ophthalmology Basic and Clinical Sciences Course. San Francisco: American Academy of Ophthalmology; 2011-2012. p. 8.Google Scholar
Holladay JT, Piers PA, Koranyi G, et al. A new intraocular lens design to reduce spherical aberration of pseudophakic eyes. J Refract Surg. 2002;18(6):683–91.PubMedGoogle Scholar
Bellucci R, Morselli S, Piers P. Comparison of wavefront aberrations and optical quality of eyes implanted with five different intraocular lenses. J Refract Surg. 2004;20(4):297–306.PubMedGoogle Scholar
Awwad ST, Warmerdam D, Bowman RW, et al. Contrast sensitivity and higher order aberrations in eyes implanted with AcrySof IQ SN60WF and AcrySof SN60AT intraocular lenses. J Refract Surg. 2008;24(6):619–25.PubMedGoogle Scholar
Campbell C. The effect of tear film on higher order corrections applied to the corneal surface during wavefront-guided refractive surgery. J Refract Surg. 2005;21(5):S519–24.PubMedGoogle Scholar
Endl MJ, Martinez CE, Klyce SD, et al. Effect of larger ablation zone and transition zone on corneal optical aberrations after photorefractive keratectomy. Arch Ophthalmol. 2001;119(8):1159–64.CrossRefPubMedGoogle Scholar
Goins KM, Wagoner MD. Focal points: imaging the anterior segment. Am Acad Ophthalmol. 2009;27(11):1–17.Google Scholar