Phakometry and lens tilt and decentration using a custom-developed Purkinje imaging apparatus: validation and measurements.
We present a Purkinje imaging system for phakometry and measurement of tilt and decentration of crystalline and intraocular lenses (IOLs). Crystalline lens radii of curvature were estimated by using both a merit function and the equivalent mirror approaches. Tilts and decentrations were estimated by using Phillips's linear analysis. We present a complete validation of the technique through exhaustive computer simulations and control experiments, and measurements in 17 normal eyes (mean age 26.67 +/- 2.31) and nine postcataract surgery eyes (mean age 74 +/- 2.3). Crystalline lens radii ranged from 12.7 to 8.81 mm and from -5.64 to -7.09 mm for anterior and posterior surfaces, respectively. Crystalline lens tilt ranged from 2.8 to -2.87 deg horizontally and from 2.58 to -1 deg vertically. Crystalline lens decentration ranged from 0.09 to 0.45 mm horizontally and from 0.09 to -0.22 mm vertically. IOL tilt ranged from 3.6 to -1.51 deg horizontally and from 5.97 to -1.85 deg vertically. IOL decentration ranged from 0.53 to -0.31 mm horizontally and from 0.13 to -0.96 mm vertically.
Rosales
Patricia
P
Instituto de Optica, Consejo Superior de Investigaciones Científicas, Madrid, Spain. Patricia@io.cfmac.csic.es
Marcos
Susana
S
D019781:Corneal Topography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007908:Lens, Crystalline / Q000502:physiology*; D007910:Lenses, Intraocular; D010865:Pilot Projects; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000175:diagnosis* / Q000503:physiopathology*; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity