TY - JOUR
T1 - Non-invasive phakometric measurement of corneal and crystalline lens alignment in human eyes
AU - Dunne, Mark C.M.
AU - Davies, Leon N.
AU - Mallen, Edward A.H.
AU - Kirschkamp, Thomas
AU - Barry, Jean-Cyriaque
PY - 2005
Y1 - 2005
N2 - We describe a non-invasive phakometric method for determining corneal axis rotation relative to the visual axis (β) together with crystalline lens axis tilt (α) and decentration (d) relative to the corneal axis. This does not require corneal contact A-scan ultrasonography for the measurement of intraocular surface separations. Theoretical inherent errors of the method, evaluated by ray tracing through schematic eyes incorporating the full range of human ocular component variations, were found to be larger than the measurement errors (β < 0.67°, α < 0.72° and d < 0.08 mm) observed in nine human eyes with known ocular component dimensions. Intersubject variations (mean ± S.D.: β = 6.2 ± 3.4° temporal, α = 0.2 ± 1.8° temporal and d = 0.1 ± 0.1 mm temporal) and repeatability (1.96 × S.D. of difference between repeat readings: β ± 2.0°, α ± 1.8° and d ± 0.2 mm) were studied by measuring the left eyes of 45 subjects (aged 18-42 years, 29 females and 16 males, 15 Caucasians, 29 Indian Asians, one African, refractive error range -7.25 to +1.25 D mean spherical equivalent) on two occasions. © 2005 The College of Optometrists.
AB - We describe a non-invasive phakometric method for determining corneal axis rotation relative to the visual axis (β) together with crystalline lens axis tilt (α) and decentration (d) relative to the corneal axis. This does not require corneal contact A-scan ultrasonography for the measurement of intraocular surface separations. Theoretical inherent errors of the method, evaluated by ray tracing through schematic eyes incorporating the full range of human ocular component variations, were found to be larger than the measurement errors (β < 0.67°, α < 0.72° and d < 0.08 mm) observed in nine human eyes with known ocular component dimensions. Intersubject variations (mean ± S.D.: β = 6.2 ± 3.4° temporal, α = 0.2 ± 1.8° temporal and d = 0.1 ± 0.1 mm temporal) and repeatability (1.96 × S.D. of difference between repeat readings: β ± 2.0°, α ± 1.8° and d ± 0.2 mm) were studied by measuring the left eyes of 45 subjects (aged 18-42 years, 29 females and 16 males, 15 Caucasians, 29 Indian Asians, one African, refractive error range -7.25 to +1.25 D mean spherical equivalent) on two occasions. © 2005 The College of Optometrists.
KW - ocular alignment
KW - ocular components
KW - phakometry
UR - http://www.scopus.com/inward/record.url?scp=21244493124&partnerID=8YFLogxK
UR - http://onlinelibrary.wiley.com/doi/10.1111/j.1475-1313.2004.00267.x/abstract
U2 - 10.1111/j.1475-1313.2004.00267.x
DO - 10.1111/j.1475-1313.2004.00267.x
M3 - Article
C2 - 15713206
SN - 0275-5408
VL - 25
SP - 143
EP - 152
JO - Ophthalmic and Physiological Optics
JF - Ophthalmic and Physiological Optics
IS - 2
ER -