Does the lens diameter increase or decrease during accommodation? Human accommodation studies: a new technique using infrared retro-illumination video photography and pixel unit measurements.
OBJECTIVE
To describe a new technique for viewing and measuring the lens diameter during accommodation.


METHODS
The accommodative lens activity, in a young female carrier of ocular albinism, was evaluated using retro-illumination infrared video photography and pixel unit measurements.


RESULTS
Right and left lens diameter measurements were 498 pu and 501 pu, respectively, during natural accommodation. In pharmacologic non-accommodation (Tropicamide), the average lens diameter was 524 pu (range 518-528) while in accommodation (Pilocarpine), the average lens diameter was 485 pu (range 479-491).


CONCLUSIONS
Right and left lens measurements were essentially identical. All measurements were reliable, repeatable and extremely accurate. The lens diameter consistently reduced during accommodation and enlarged during non-accommodation. The theories, similar to Tscherning's, which imply that the lens diameter increases in accommodation, are clearly disproven.
Wilson
R S
RS
Retinal Group, Ltd., Little Rock, AR 72205, USA.
D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D016117:Albinism, Ocular / Q000503:physiopathology; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007259:Infrared Rays; D007908:Lens, Crystalline / Q000033:anatomy & histology / Q000502:physiology*; D010781:Photography; D015203:Reproducibility of Results; D014741:Video Recording