Abstract
Purpose::
To determine the relationship between cataract type and higher-order aberrations (HOA).
Methods::
Ninety-eight eyes were evaluated of 101 subjects (mean age 73.43, SD 9.08) who presented consecutively to undergo cataract extraction and intra-ocular lens implantation. Root mean square (RMS) values were separately evaluated for the HOA components Total, TiltS1, High, TComa, TTrefoil, T4foil, TSph and HiAstg using the NIDEK Optical Path Difference Scanning System ARK-10000 aberrometer. Cataract was graded using the Lens Opacity Classification System (LOCS) III for type (Nuclear Opalescence/NO, Nuclear Color/NC, Cortical/C and Posterior/P) and severity (levels 0 through 6). For each of the eight HOAs, Analysis of Variance and post-hoc contrasts were employed to evaluate differences in RMS values between the various types of cataract. For more complex combinations of NO, NC and P cataract, Analysis of Co-variance was used, comparing grouped NO and NC levels 2-5 with level 6, and P type levels 0, 1-4 and 5.
Results::
There was a significant difference in the RMS values for each HOA between level 5 compared to lower levels for P cataract and between level 6 compared to lower levels for NO and NC cataract. RMS values of C cataract did not differ between levels. A significant correlation was present between the level of P cataract and the RMS value for each HOA and between the level of combined NO/NC group and the RMS value for each HOA except Trefoil. In addition, both spherical equivalent and pupil size were correlated with several types of HOA. For all HOA types, the P cataract contributed most to the corresponding RMS values.
Conclusions::
The combination of advanced posterior sub-capsular cataract with advanced nuclear cataract induces significant levels of HOA. Cortical cataract has little effect on HOA.