The impact of cataract, and its surgical removal, on measures of macular pigment using the Heidelberg spectralis HRA+OCT multicolor device

PURPOSE. To investigate the effect of cataract (and cataract surgery) on macular pigment (MP) measurements using the Heidelberg Spectralis HRA+OCT MultiColor device. METHODS. Thirty-six patients (age, 54-87 years) scheduled for cataract surgery at the Institute of Eye Surgery, Ireland, were enrolled in this study. Cataracts were graded using the Lens Opacities Classification System (LOCS) III, and surgery was performed using standard phacoemulsification technique with implantation of a Tecnis ZCB00 or Tecnis ZCT intraocular lens. Macular pigment was measured before and after cataract surgery in the operated (study) eye and in the fellow (control) eye. RESULTS. In the study eye, there was statistically significant disagreement in measures of MP taken before and after surgery. At all eccentricities, and also for MP volume, the postsurgery measurements were significantly (P < 0.05) greater, ranging from an average 16% greater at 1.72° to an average 35% greater at 0.23° eccentricity. Eyes exhibiting large disagreement between pre- and postsurgery measurements at a given eccentricity also generally exhibited substantial disagreement at other eccentricities. Overall severity of cataract contributed to greater disagreement between pre- and postoperative measures of MP, as did grade of nuclear opalescence, nuclear color, and posterior subcapsular cataract. In control eyes, there was no statistically significant disagreement in terms of measures of MP taken before and after cataract surgery (P > 0.05 for all; 1-sample t-test). CONCLUSIONS. Macular pigment measurements using the Spectralis are affected by cataract. Accordingly, we recommend that cataract be graded when measuring MP with a device that utilizes dual-wavelength fundus autofluorescence and propose the employment of a correction factor to compensate for cataract when measuring MP.