Purpose To evaluate mesopic contrast sensitivity with or without glare in eyes with early nuclear cataract, and to investigate the relationship among mesopic contrast sensitivity, ocular higher-order wavefront aberrations, and severity of lens opacity.
Methods Photopic and mesopic contrast sensitivity was measured using OPTEC6000 Vision Tester (Stereo Optical) in 23 eyes of 21 subjects with early nuclear cataract (9 males and 12 females, mean age +/- standard deviation, 68.4 +/- 9.0 years), whose best-corrected visual acuity was 20/20 or better. From the contrast sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. Ocular higher-order aberrations (HOA) were measured for a 6-mm pupil using a Hartmann-Shack wavefront analyzer. The root-meat-square (RMS) of third- plus fifth-order Zernike coefficients, and fourth- plus sixth-order Zernike coefficients were used to represent coma-like and spherical-like aberrations under mesopic condition, respectively. The density of lens opacity was quantitatively assessed from Scheimpflug images using the EAS-1000 (Nidek). The relationship among mesopic contrast sensitivity, HOA and lens density was investigated.
Results Mesopic AULCSF was significantly lower than photopic AULCSF (P< 0.001). With the presence of glare, mesopic AULCSF decreased furthermore (P< 0.001), while photopic AULCSF remained unchanged (P= 0.143). Multiple linear regression analysis revealed that lens density (P =0.035) and coma-like aberrations (P = 0.037) were significantly associated with mesopic AULCSF with glare, while only lens density was significantly associated with mesopic AULCSF without glare (P= 0.049).
Conclusions  In early nuclear cataract eyes, lens density significantly influences mesopic contrast sensitivity. Mesopic contrast sensitivity with glare is affected by coma-like aberrations as well.