Apparent accommodation and depth of field in pseudophakia.
OBJECTIVE
To assess depth of field in phakic and pseudophakic eyes to explain good distance and uncorrected near visual acuity in pseudophakic eyes.


METHODS
Department of Ophthalmology, University of Otago Medical School, Dunedin, New Zealand.


METHODS
Depth of field was measured in pseudophakic (n = 10) and phakic (n = 10) eyes for both near and distant targets. Test conditions included cycloplegia and a constant pupillary aperture using a soft contact lens with a central artificial pupil diameter of 2.5 mm.


RESULTS
There was no statistically significant difference between phakic and pseudophakic eyes for any test. Depth of field for near visual acuity was +/-0.85 diopters (D), but amplitude of legibility was +/-1.94 D. Depth of field for distance visual acuity was between 0.25 and 0.50 D in 85% of eyes.


CONCLUSIONS
In the absence of astigmatism and disease, a pseudophakic eye with -0.75 D of myopia can expect to achieve 20/30 uncorrected distance acuity and read N5 unaided if the pupil is approximately 2.5 mm.
Elder
M J
MJ
Department of Ophthalmology, Christchurch Hospital, New Zealand.
Murphy
C
C
Sanderson
G F
GF
D000065:Accommodation, Ocular; D002387:Cataract Extraction; D003261:Contact Lenses; D003867:Depth Perception; D006801:Humans; D007908:Lens, Crystalline / Q000502:physiology; D007910:Lenses, Intraocular; D012030:Refractive Errors / Q000503:physiopathology; D014792:Visual Acuity