Purchase this article with an account.
Sally A McFadden, Callan Medcalf, Guang Zeng, John Holdsworth; Comprehensive lesions of the retina surrounding the optic nerve enhance elongation and cause myopia in the guinea pig eye. Invest. Ophthalmol. Vis. Sci. 2014;55(13):3601.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Disruption to detailed vision using form deprivation (FD) induces excessive eye elongation and myopia. The underlying mechanisms are local to the eye since FD myopia induces excessive growth after optic nerve section.1 Surprisingly, foveal photoablation does not inhibit FD myopia in young monkeys.2 However, the region around the optic nerve (the peripapillary zone or PPZ) expands early during myopia development and the overlying retina may carry the pertinent signals.3 We studied the effect of retinal photocoagulation lesions of the PPZ on both normal and myopic growth.
Guinea pigs received FD alone (n = 16) or comprehensive PPZ lesions using multiple spots (laser strength of 100 mW for 50 ms, n = 9) the day prior to FD. FD involved wearing a diffuser over one eye from 6 to 13 days of age. PPZ lesions were also administered at the same age in a group not form deprived (n = 7). Refractive error (using a Nidek autorefractor after cycloplegia) and eye shape (based on retinal hemisections4) were assessed at the end of the rearing period. Results are presented as the relative differences between the two eyes.
FD alone resulted in -3.1D of relative myopia and 100 µm of relative eye elongation in the PPZ area with relative eye shrinkage (-47 µm) in the temporal retina. Greater myopia was observed after PPZ lesions combined with FD (-7.35D, 150 µm) and unlike normal FD, excessive growth also occurred in the mid periphery, particularly in nasal retina. PPZ lesions also induced relative myopia in animals not form deprived (-3.8D, p < 0.001).
Retinal signals from the PPZ may be critical for normal refractive development and when eliminated, cause exaggeration of the central elongation so characteristic of myopic eyes. Without these signals, the eye also grows excessively in the periphery suggesting they are necessary for relative growth inhibition. 1. Smith EL et al. IOVS (2007), 48(9), 3914-3922. 2. Wildsoet CF, McFadden SA. IOVS (2010) 51 ARVO E-Abstract 1737. 3. Zeng G, McFadden SA. IOVS (2011) 52 ARVO E-Abstract 3923. 4. Zeng G et al. Vision Res. (2013), 76, 77-88.
This PDF is available to Subscribers Only