Download Ocular growth guided by dual focal fresnel lenses requires

ABSTRACT TITLE
TITLE: Ocular growth guided by dual focal fresnel lenses requires an intact optic nerve
PROGRAM # (Final ID)
ABSTRACT FINAL ID: 4038
SESSION TYPE: Paper Session
POSTER BOARD # (DOI)
DIGITAL OBJECT IDENTIFIER (DOI):
PRESENTATION START/END
SESSION ABSTRACT START TIME: 9:15 AM
SESSION ABSTRACT END TIME: 9:30 AM
SESSION # (Abbreviation)
SESSION ABBREVIATION: 406
SESSION TITLE: Myopia and Emmetropization
SESSION DAY & DATE: Wednesday, May 8, 2013
SESSION START TIME: 8:30 AM
SESSION END TIME: 10:15 AM
AUTHORS (LAST NAME, FIRST NAME): McFadden, Sally A.1; Tse, Dennis Y.2; To, Chi-ho2; Wildsoet,
Christine F.3
INSTITUTIONS (ALL): 1. School of Psychology, University of Newcastle, Callaghan, NSW, Australia.
2. School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
3. School of Optometry, University of California, Berkeley, CA, United States.
Study Group:
ABSTRACT BODY:
Purpose: Hyperopic defocus imposed with a negative lens induces myopia from excessive ocular growth while
positive lenses cause ocular growth to slow. When negative and positive powers are combined 50:50 in a Fresnel
lens, ocular growth is matched to the average imposed defocus. We asked whether this apparent integration occurs
in eyes with sectioned optic nerves.
Methods: 47 guinea pigs underwent either optic nerve section (ONS) or sham surgery at 3 days of age in one eye.
The treated eye then wore either a single vision lens (-5 D or 0 D) or a Fresnel lens composed of two powers in
equal ratios (-5/+5 D, -5/0 D, +5/0 D) for 11 days (from 6-16 days of age). Refractive error and axial ocular
dimensions were measured before and after treatments. Interocular differences in refractive error and axial length
after treatment are reported.
Results: After ONS, eyes with -5 D lenses became excessively myopic (-6.4 ± 1.6 D, p = 0.006) and elongated
(150 ± 22 µm, p = 0.02) while there was little effect of ONS with no defocus (0 D: -1.4 ± 1.7 D, p = 0.08 and 87
± 103 µm, p = 0.02). After sham surgery, eyes wearing -5/+5 D Fresnel lenses responded to the average imposed
defocus (Refractive Error: -0.8 ± 0.7 D, p = 0.4; Axial Length: 65 ± 13 µm, p = 0.2), while after ONS, the same
-5/+5 D lenses induced myopia (-5.2 ± 1.5 D) and excessive elongation (151 ± 36 µm). Similarly, ONS eyes
wearing -5/0 D or +5/0 D lenses failed to integrate the dual defocus, and the degree of myopia and ocular
elongation was similar to that in animals wearing -5/+5 D or -5 D lenses (-5/0 D: -5.8 ± 1.2 D; +5/0 D: -7.2 ± 1.3
D; F(3,38) = 0.3, p = 0.8).
Conclusions: An intact optic nerve is required for the integration of imposed optical defocus. Therefore, either
ONS rapidly alters retinal processing and causes this failure, or neural processes beyond the eye contribute to the
inhibition of mammalian eye growth and are required for the ocular growth response to dual focal lenses.
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Commercial Relationship(s) Disclosure:
Sally McFadden: Commercial Relationship: Code N (No Commercial Relationship)
Dennis Tse: Commercial Relationship: Code N (No Commercial Relationship)
Chi-ho To: Commercial Relationship: Code N (No Commercial Relationship)
Christine Wildsoet: Commercial Relationship: Code N (No Commercial Relationship)
Grant Support: Yes
Support Detail: Australian DIIRSE International Science Linkage CG120160 (SAM), NIH R01 EY12392
(CFW, SAM), Niche Area Fund Hong Kong JBB7P (CHT, DYT)
Clinical Trial Registration: No
Other Registry Site:
Registration Number: