Comparison of the ocular wavefront aberration between pharmacologically-induced and stimulus-driven accommodation.
OBJECTIVE
To compare the ocular wavefront aberration between pharmacologically- and stimulus-driven accommodation in phakic eyes of young subjects.


METHODS
The aberration structure of the tested eye when accommodating was measured using the Complete Ophthalmic Analysis System (COAS; AMO WaveFront Sciences, Albuquerque, NM, USA). It was used in conjunction with a purposely-modified Badal optometer to allow blur-driven accommodation to be stimulated by a high contrast letter E with a vergence range between +0.84 D and -8.00 D. Pharmacological accommodation was induced with one drop of pilocarpine 4%. Data from six subjects (age range: 23-36 years) with dark irides were collected.


RESULTS
No correlation was found between the maximal levels of accommodative response achieved with an 8 D blur-driven stimulus and pharmacological stimulation. Pharmacological accommodation varied considerably among subjects: maximum accommodation, achieved within 38-85 min following application of pilocarpine, ranged from 2.7 D to 10.0 D. Furthermore, although the changes of spherical aberration and coma as a function of accommodation were indistinguishable between the two methods for low levels of response, a characteristic break in the pattern of aberration occurred at higher levels of pilocarpine-induced accommodation. This probably resulted from differences in the time course of biometric changes occurring with the two methods.


CONCLUSIONS
Measuring the pilocarpine-induced accommodative response at only one time point after its application may lead to misleading results. The considerable inter-individual differences in the time course of drug-induced accommodative response and its magnitude may lead to overestimation or underestimation of the corresponding amplitude of normal, blur-driven accommodation. Stimulating accommodation by topical application of pilocarpine is inappropriate for evaluating the efficacy of 'accommodating' IOLs.
Plainis
S
S
Institute of Vision and Optics, School of Health Sciences, University of Crete, Heraklion, Crete 71003, Greece. plainis@med.uoc.gr
Plevridi
E
E
Pallikaris
I G
IG
D000065:Accommodation, Ocular / Q000187:drug effects* / Q000502:physiology; D000328:Adult; D003290:Convergence, Ocular / Q000187:drug effects* / Q000502:physiology; D005123:Eye / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008916:Miotics / Q000494:pharmacology*; D010829:Physiological Phenomena / Q000187:drug effects; D010862:Pilocarpine / Q000494:pharmacology; D012029:Refraction, Ocular / Q000187:drug effects*; D014792:Visual Acuity / Q000187:drug effects* / Q000502:physiology; D055815:Young Adult
D008916:Miotics; D010862:Pilocarpine