Scientific contributions

RESEARCH AND TECHNOLOGY TRANSFER

Scientific contributions

My research combines the development of optical instruments for the living eye with the study of the mechanisms that determine visual quality. Transferring techniques from optics to vision science and ophthalmology has helped turn laboratory prototypes into clinical tools.

Early contributions include double-pass instrumentation, using a laser to illuminate the eye and a camera to record the retinal image. This work opened new approaches to studying ocular optics and contributed to aberrometry, including Hartmann–Shack wavefront sensing.

A central finding was the coupling between corneal and crystalline-lens aberrations, which improves retinal image quality. The young eye partially compensates spherical aberration and coma; this balance deteriorates with age. These findings provided a basis for a new generation of aspheric intraocular lenses.

Adaptive optics enabled real-time measurement and correction of ocular aberrations and the development of visual simulators for testing new optical solutions. Other research areas include peripheral vision, light scattering, imaging through cataracts, two-photon vision and intraocular lenses, including inverted-meniscus ArtIOLs.

Key scientific achievements

1. I developed double-pass instrumentation to record and analyse the eye’s point spread function. This work contributed to clinical instruments for assessing optical quality and cataracts.
2. With my collaborators, I discovered that crystalline-lens aberrations partially compensate corneal aberrations. This finding provided one of the optical rationales for the development of aspheric intraocular lenses.
3. We showed that the young eye behaves approximately as an aplanatic system, partially compensating spherical aberration and coma.
4. We investigated how neural adaptation compensates each eye’s particular pattern of higher-order aberrations.
5. We obtained evidence that cone photoreceptors could be imaged in the living eye using speckle interferometry, an early contribution to high-resolution retinal imaging.
6. I proposed and developed adaptive optics visual simulators with my group to evaluate vision under controlled optical conditions. We also developed binocular versions.
7. We characterised peripheral retinal optics in natural eyes and eyes with intraocular lenses.
8. We developed instruments for precise, objective measurement of light scattering in the human eye.
9. We investigated the mechanisms underlying night myopia.
10. We designed intraocular optical solutions for patients with macular degeneration.
11. We developed a single-pixel ophthalmoscope to image the retina through severe ocular opacities.
12. We developed nonlinear multiphoton microscopy for the living cornea.
13. We measured visual acuity using two-photon absorption processes with infrared light.
14. We designed new types of intraocular lenses to improve peripheral retinal optics.
15. We characterised colour perception in two-photon vision.

Clinical, social and academic impact

1. The double-pass technique I developed with my collaborators was translated into clinical instruments such as Visiometrics’ OQAS and HD Analyzer for assessing optical quality and cataracts.
2. My research contributed to the understanding and measurement of ocular wavefronts used in clinical aberrometry.
3. Our findings on the compensation of aberrations between the cornea and crystalline lens helped establish a rationale for intraocular lens designs that seek to reproduce optical properties of the young eye.
4. The adaptive optics visual simulators we developed allow optical solutions to be compared before they are applied to a patient. Voptica’s VAO is a commercial clinical application of this research.
5. The instruments we developed to measure intraocular scattering have applications in assessing cataracts and tear-film quality.
6. We investigate imaging through turbid ocular media, with potential applications in viewing the retina behind a cataract and in optoelectronic visual aids.
7. I am the inventor of inverted-meniscus ArtIOLs intraocular lenses, developed by Voptica. Their design aims to improve peripheral optical quality. I have also worked on intraocular designs for macular degeneration.
8. I have co-founded technology companies, including Visiometrics and Voptica, both of which operate internationally.
9. I am the editor of the Handbook of Visual Optics: the first edition was published in 2017 and the second, in two volumes, in 2026.
10. I share science through books and newspaper articles. My two personal blogs remain available as archives, with reflections on research, ethics and scientific careers.

Eight selected papers

1. Double pass

   Artal, Marcos, Navarro & Williams. Odd aberrations and double-pass measurements of retinal image quality. JOSA A 12, 195–201 (1995).

2. Cornea–lens compensation

   Artal & Guirao. Contributions of the cornea and the lens to the aberrations of the human eye. Optics Letters 23, 1713–1715 (1998).

3. Cornea–lens compensation

   Artal, Guirao, Berrio & Williams. Compensation of corneal aberrations by the internal optics in the human eye. Journal of Vision 1(1), 1 (2001).

4. Adaptive optics visual simulation

   Manzanera, Prieto, Ayala, Lindacher & Artal. Liquid crystal adaptive optics visual simulator: application to testing and design of ophthalmic optical elements. Optics Express 15, 16177–16188 (2007).

5. Binocular visual simulation

   Fernández, Prieto & Artal. Binocular adaptive optics visual simulator. Optics Letters 34, 2628–2630 (2009).

6. Peripheral vision

   Artal, Derrington & Colombo. Refraction, aliasing, and the absence of motion reversals in peripheral vision. Vision Research 35, 939–947 (1995).

7. Two-photon infrared vision

   Artal, Manzanera, Komar, Gambín-Regadera & Wojtkowski. Visual acuity in two-photon infrared vision. Optica 4, 1488–1491 (2017).

8. Mechanisms of infrared vision

   Manzanera, Sola, Khalifa & Artal. Vision with pulsed infrared light is mediated by nonlinear optical processes. Biomedical Optics Express 11, 5603–5617 (2020).