Relationship between intraocular pressure and eye growth in chick

Schmid, Katrina L., Hills, Tracy, Abbott, Meredith, Humphries, Michelle, Pyne, Kylie, & Wildsoet, Christine F. (2003) Relationship between intraocular pressure and eye growth in chick. Ophthalmic and Physiological Optics, 23(1), pp. 25-33.

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In infants, abnormally high intraocular pressure (IOP) results in excessive eye enlargement. In the study reported here, we investigated whether IOP might be a determinant of ocular elongation using the chick as an animal model. Specifically, we examined IOP changes in (I). normally developing eyes, and (II). eyes undergoing altered growth. In the first case (I). developmental changes in IOP, axial length and refractive error were assessed at approximately daily intervals during early development (days 2-11 post-hatch, n = 8), and at weekly intervals from weeks 1 to 6 (n = 8). In the second case (II). opposite ocular growth responses were elicited using -15 D and +15 D defocusing spectacle lenses fitted monocularly to 8-day-old chicks (n = 8 and 7, respectively). Treated eyes were measured 3 and 7 h after lens application (between 9 and 10 am), as well as 1, 2 and 4 days later, around the same time as the initial lens application. In normal development (I). IOP increased over the first post-hatch week, peaking at 18.0 +/- 5.1 mmHg, and declined slowly thereafter to be back to near 'hatching' values at 6 weeks (12.7 +/- 5.3 mmHg at day 2 cf. 13.4 +/- 1.9 mmHg). Eyes elongated at an approximately linear rate over the entire monitoring period. The -15 D and +15 D lenses (II). produced opposing effects on eye growth, as indicated by axial length changes of + 0.67 +/- 0.25 mm cf. -0.33 +/- 0.17 mm over the 4-day treatment period. Both groups showed decreases in IOP over the first 20 h of lens wear. The faster growing eyes of the -15 D group exhibited a later relative increase in IOP. The described changes in IOP are compatible with, but do not prove, a modulatory influence of IOP on early eye growth.

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ID Code: 4263
Item Type: Journal Article
Refereed: Yes
Keywords: Chickens/, growth & development, Eye/, growth & development, Intraocular Pressure/, physiology, Analysis of Variance, Animals, Contact Lenses, Models, Animal, Refractive Errors, Research Support, Non, U, S, Gov't
DOI: 10.1046/j.1475-1313.2003.00085.x
ISSN: 0275-5408
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Optometry & Vision Science
Copyright Owner: Copyright 2003 Blackwell Publishing
Copyright Statement: The definitive version is available at
Deposited On: 19 Jul 2006 00:00
Last Modified: 27 Sep 2013 06:10

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