Skip to main content
SpringerLink
Log in

Visual optics in toads (Bufo americanus)

  • Published:
Journal of Comparative Physiology A Aims and scope Submit manuscript

Summary

Aspects of visual optics were investigated in the American toad (Bufo americanus). The development of the refractive state of the eye during metamorphosis was followed with IR photoretinoscopy. Frozen sections documented the changes in optical parameters before and after metamorphosis. There is a difference in light sensitivity between juvenile and adult toads. Binocular accommodation in adult toads was observed.

  1. 1.

    IR photoretinoscopic measurements showed that the refractive state of the eye changed very rapidly during metamorphosis, about 10D/h while the animal entered the terrestrial habitat.

  2. 2.

    Frozen sections showed that the almost spherical lens in a tadpole eye had flattened in a just metamorphosed toad's eye while at the same time the distance of the lens to the retina had decreased. However, the morphological measurements were not sufficiently sensitive to record the relatively small changes in ocular dimensions that were responsible for the rapid changes in refractive state during metamorphosis.

  3. 3.

    Schematic eyes, with homogeneous and non homogeneous lenses, were constructed for tadpoles, juvenile toads, and adult toads.

  4. 4.

    Nonparaxial raytracing studies in schematic eyes suggested that the lenses of animals of the three developmental stages tadpole, juvenile toad, and adult are not homogeneous but have a refractive index gradient. The raytracing studies indicated that the refractive index gradient is different for the different developmental stages, being highest in the tadpole lens.

  5. 5.

    The observations of toads during feeding behavior at different light levels showed an increased light sensitivity in the adult nocturnal toads in contrast to the juvenile animals, which are diurnal. The increased light sensitivity could partly be explained with an increase in aperture and an increase in red rod outer segments. To fully explain the higher light sensitivity in adult toads, changes in neuronal parameters had to be assumed.

  6. 6.

    Retinoscopic measurements of the resting refractive state in the adult toad showed a hyperopic defocus of about +8D. By subtracting the measurement artefact for retinoscopy, the true resting focus was found to be nearly emmetropic.

  7. 7.

    The amount of natural accommodation in adult toads during normal feeding behavior was investigated with IR photoretinoscopy. Binocular accommodation of about 8D was observed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Abbreviations

D :

Diopter

IR :

infrared light

LED :

light emitting diode

ROS :

red rod outer segments

SF :

shape factor

References

  • Beer T (1898) Die Akkommodation des Auges bei den Amphibien. Pflügers Arch Ges Physiol 73:501–534

    Google Scholar 

  • Birukow G (1950) Vergleichende Untersuchungen über das Helligkeits- und Farbensehen bei Amphibien. Z Vergl Physiol 32:348–382

    Google Scholar 

  • Bowmaker JK (1977) The visual pigments, oil droplets and spectral sensitivity of the pigeon. Vision Res 17:1129–1138

    Google Scholar 

  • Bowmaker JK, Dartnall HJA (1980) Visual pigments of rods and cones in a human retina. J Physiol (Lond) 298:501–511

    Google Scholar 

  • Bowmaker JK, Martin GR (1978) Visual pigments and colour vision in a nocturnal bird,Strix aluco (Tawny owl). Vision Res 18:1125–1130

    Google Scholar 

  • Brahma SK, Bours J (1972) Thin layer isoelectric focusing of the soluble lens extracts from larval stages and adultXenopus laevis. Exp Eye Res 13:309–314

    Google Scholar 

  • Collett TS (1977) Stereopsis in toads. Nature 267:349–351

    Google Scholar 

  • Crescitelli F (1958) The natural history of visual pigments. In: Newburgh RW (ed) Photobiology, Biology Colloquium, Oregon State College, Corvallis, pp 30–51

    Google Scholar 

  • Davson H (1984) Vegetative physiology and biochemistry. vol IA In: Davson H (ed) The eye. Academic Press, London

    Google Scholar 

  • Douglas RH, Collett TS, Wagner HJ (1986) Accommodation in anuran Amphibia and its role in depth vision. J Comp Physiol A 158:133–143

    Google Scholar 

  • Doyle MJ, Maclean N (1978) Biochemical changes in developmentally retardedXenopus laevis. I. The lens crystallin transition. J Embryol Exp Morphol 46:215–255

    Google Scholar 

  • Duke-Elder S (1958) The eye in evolution. (System of ophthalmology, vol I) Henry Kimpton, London

    Google Scholar 

  • Eibl-Eibesfeldt I (1967) Nahrungserwerb und Beuteschema der Erdkröte. Behavior 4:1–35

    Google Scholar 

  • Eikmanns KH (1955) Verhaltensphysiologische Untersuchungen über den Beutefang und das Bewegungssehen der Erdkröte (Bufo bufo L.). Z Tierpsych 12:229–253

    Google Scholar 

  • Fisher LF (1972) Changes during maturation and metamorphosis in the synaptic organization of the tadpole retina inner plexiform layer. Nature 235:391–393

    Google Scholar 

  • Glickstein M, Millodot M (1970) Retinoscopy and eye size. Science 168:605–606

    Google Scholar 

  • Gordon J, Hood DC (1976) Anatomy and physiology of the frog retina. In: Fite K (ed) The amphibian visual system. Academic Press, New York, pp 29–86

    Google Scholar 

  • Hess C von (1911) Beiträge zur vergleichenden Akkommodationslehre. Zool Jahrb 30:339–359

    Google Scholar 

  • Heuscer H von (1956) Zum geruchlichen Beutefinden und Gähnen der Kreuzkröte (Bufo calamita Laur.). Z Tierpsychol 15:94–98

    Google Scholar 

  • Hinsehe G (1935) Ein Schnappreflex nach Nichts bei Anuren. Zool Anz 3:113–122

    Google Scholar 

  • Hirschberg I (1882) Zur Dioptrik und Ophthalmoskopie der Fisch- und Amphibienaugen. Arch Anat Physiol Abt Physiol 1882:493–526

    Google Scholar 

  • Howland HC (1985) Optics of photoretinoscopy: results from raytracing. Am J Optom Physiol Opt 62:614–620

    Google Scholar 

  • Ingle DJ (1968) Visual releasers of prey catching behavior in frogs and toads. Brain Behav Evol 1:500–518

    Google Scholar 

  • Ingle DJ (1976) Spatial vision in anurans. In: Fite K (ed) The amphibian visual system. Academic Press, New York, pp 119–149

    Google Scholar 

  • Jordan M, Luthardt G, Meyer-Naujoks Chr, Roth G (1980) The role of eye accommodation in the depth perception of common toads. Z Naturforsch 35c:851–852

    Google Scholar 

  • Koneff (1938) Mallory Heidenhain's azan stain. In: Humason GL (ed) Animal tissue techniques. Freeman and Company, San Francisco, pp 163–165

    Google Scholar 

  • Krüger H, Moser EA (1971) Refraktion und Abbildungsgesetze des Froschauges. Pflügers Arch 326:334–852

    Google Scholar 

  • Larsen LO, Pedersen JN (1982) The snapping response of the toad,Bufo bufo, towards prey dummies at very low light intensities. Amph Rept 2:321–327

    Google Scholar 

  • Manteuffel G, Wess O, Himstedt W (1977) Measurements of the dioptric apparatus in amphibian eyes and calculations of the visual acuity in water and in air. Zool Jb Physiol 81:395–406

    Google Scholar 

  • Martin GR (1982) An owl's eye: schematic optics and visual performance inStrix aluco L. J Comp Physiol 145:341–349

    Google Scholar 

  • Millodot M (1971) Measurement of the refractive state of the eye in frogs (Rana pipiens). Rev Can Biol 30:249–252

    Google Scholar 

  • Millodot M (1974) Optical measurement of the refraction of the eyes in frogs (Rana pipiens). Pflügers Arch 351:173–175

    Google Scholar 

  • Moser EA, Krüger H (1972) Retinoscopic and neurophysiological refractometry inRana temporaria. Pflügers Arch 335:235–242

    Google Scholar 

  • Muntz WRA, Reuter T (1966) Visual pigments and spectral sensitivity inRana temporaria and other European tadpoles. Vision Res 6:601–618

    Google Scholar 

  • Pont JS du, de Groot PJ (1976) A schematic dioptric apparatus for the frog's eye (Rana esculenta). Vision Res 16:803–810

    Google Scholar 

  • Schaeffel F, Howland HC (1987) Corneal accommodation in chick and pigeon. J Comp Physiol A 160:375–384

    Google Scholar 

  • Sivak JG, Warburg MR (1980) Optical metamorphosis of the eye ofSalamandra salamandra. Can J Zool 58:2059–2064

    Google Scholar 

  • Taigen TL, Pough FH (1981) Activity metabolism of the toad (Bufo americanus): ecological consequenes of ontogenetic change. J Comp Physiol 144:247–252

    Google Scholar 

  • Tretjakoff D (1913) Zur Anatomie des Auges der Kröte. Z Wiss Zool 80:327–359

    Google Scholar 

  • Tsukamoto Y (1987) Morphometrical features of rod outer segments in relation to visual acuity and sensitivity in the retina ofRana catesbeiana. Zool Sci 4:233–242

    Google Scholar 

  • Walls GL (1942) The vertebrate eye and its adaptive radiation. Hafner Publishing Co., New York, London

    Google Scholar 

  • Werner C, Himstedt W (1984) Eye accommodation during prey capture behavior in salamanders (Salamandra salamandra L.). Behav Brain Res 12:69–73

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Section of Neurobiology and Behavior, Cornell University, 14853, Ithaca, New York, USA

    Ute Mathis, Frank Schaeffel & Howard C. Howland

Authors
  1. Ute Mathis
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Frank Schaeffel
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Howard C. Howland
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Mathis, U., Schaeffel, F. & Howland, H.C. Visual optics in toads (Bufo americanus). J. Comp. Physiol. 163, 201–213 (1988). https://doi.org/10.1007/BF00612429

Download citation

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00612429

Keywords

Search

Navigation