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Changes in objective refraction after pharmacological pupil dilation
Author(s) -
WAKPI DJEUGUE D,
TOUZEAU O,
BASLI E,
GAUJOUX T,
BORDERIE VM,
LAROCHE L
Publication year - 2010
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2010.487.x
Subject(s) - keratometer , ophthalmology , refraction , tropicamide , refractometer , dilation (metric space) , pupillary response , meridian (astronomy) , mathematics , optics , medicine , pupil , refractive index , cornea , physics , geometry , astronomy
Purpose To analyze the variation of the objective refraction induced by pharmacological pupillary dilation in a normal population. Methods The objective refraction obtained by an auto‐kerato‐refractometer was analyzed before and after maximum pupillary dilation obtained by 0.5% Tropicamide and 10% Phenylephrine. 200 phakic eyes of 100 patients aged from 15 to 76 years were prospectively included. The refractive data were expressed in a dioptric space by 3 Cartesian coordinates (X, Y, Z). Results After pupil dilation, the mean refraction ranges from ‐0.08(+0.11)×90.2° to +0.41(+0.10)×90.3° this equal to an astigmatic vectorial variation of (+0.03)×89.6°. The spherical equivalent increases significantly (hyperopization of +0.49D: +0.24D vs +0.74D p<0.001) contrary to the mean keratometry (43.48D vs 43.49 p=0.40) and the cylinder (0.64D vs 0.64D p=0.49) which are unchanged. Change in spherical equivalent is correlated with the age (r=‐0.34 p<0.001) but not with the change in keratometry (r=0.06 p=0.20) or the initial spherical equivalent (r=‐0.05 p=0.23). The mean change in axis between both exams is 15.4° for the ocular astigmatism and 12.2° for the corneal astigmatism. The modification in spherical equivalent of both eyes of a patient are not different (p=0.26) and are strongly correlated (r=0.85 p<0.001) contrary to the modification in axis and in cylinder. Conclusion Pharmacological pupil dilation modifies primarily the spherical equivalent without significant modification of keratometry and astigmatism. Finally, hyperopization is probably due to the cycloplegic effect of eye drops.