In vivo laser scanning confocal microscopy confirms that the human corneal sub-basal nerve plexus is a highly dynamic structure
Dipika V Patel 1*
and
Charles N.J. McGhee 2
1 Department of Ophthalmology, University of Auckland, Private Bag 92019, Auckland, 1001, New Zealand
2 Department of Ophthalmology, The University of Auckland, Auckland, New Zealand
* To whom correspondence should be addressed. E-mail: dipika.patel{at}auckland.ac.nz.
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Abstract |
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Purpose
We have previously reported on the 2 dimensional arrangement of the living human sub-basal corneal nerve plexus and this study aimed to determine whether this is a dynamic structure.
Methods
Laser scanning in vivo confocal microscopy was performed on the left cornea of a healthy subject. This subject had been examined using the same methodology 2 years previously. Examinations were performed once a week for 6 weeks with the aim of producing a 2 dimensional reconstruction map of the living, human, sub-basal corneal nerve plexus at each session. Macromedia Freehand was used to arrange and map images obtained at each session into confluent montages.
Results
The mean dimensions of the corneal areas mapped were 4.80±0.45mm horizontally and 4.60±0.52mm vertically. The nerve branching patterns observed 2 years previously did not correspond with those in any recent maps. Over the 6 week period, the sub-basal nerve pattern appeared to migrate centripetally from the corneal periphery towards an infero-central whorl. In the region of the whorl the nerves altered their generally centripetal direction of migration, undergoing clockwise rotation. The centripetal rate of migration decreased with proximity to the centre of the whorl (5.6±3.4µ/week at 13µm from whorl, 13.9±5.5µm/week at 333µm from whorl, and 25.9±8.6µm/week at 698µm from whorl).
Conclusion
This study provides strong evidence that the living human sub-basal corneal nerve plexus is a highly dynamic structure - with continuous centripetal movement of identifiable branch points, of up to 26µm/week, creating dramatic pattern changes in the plexus over a 6 week period.
Key Words:
cornea, nerves, in vivo confocal microscopy, sub-basal nerves
