Abstract
Purpose: :
To investigate the effect of intra ocular lens implants (IOLs) on the diagnostic performance of 4 variants of multifocal Pupil Objective Perimetry (mfPOP) in glaucoma.
Methods: :
We tested 77 normal subjects (age 62.7 ± 8.9SD), including 34 IOL eyes. The glaucoma group consisted of 87 subjects (age 67.9 ± 9.8SD), with 40 IOL eyes. Glaucoma subjects had moderate to severe visual fields in at least one eye. Subjects were examined with HFA achromatic, SWAP and Matrix 24-2 perimetry, Stratus OCT. Visual fields were classified according to their HFA mean defects: mild <=6 dB, moderate 6 to 12 dB, severe > 12 dB. Informed written consent was obtained from all subjects. Multifocal stimuli having 24 test regions/eye, extending to 30 deg eccentricity, were presented concurrently to both eyes using a prototype of the TrueField Analyzer. Recording duration was 4 minutes, divided into 8 segments of 30 s. Segments were repeated if more than 15% of the data was lost due to blinks or fixation losses, monitored in real time under infrared illumination. Four stimulus protocols were examined which differed in mean presentation rate (4/s or 2/s) and flicker rate (15Hz or 30Hz). Peak stimulus luminance of 290 cd/m2 and background of 10 cd/m2 were used. The measure of diagnostic performance was area under the curve (AUC) of receiver operator characteristics (ROC) plots and the method used to determine the effect of IOLs on pupil responses for both groups was multiple regression analysis.
Results: :
The best diagnosticity was achieved with the 4/s and 15 Hz protocol, with 94.98% AUC in subjects with IOLs and 94.48% AUC in subjects without IOLs. As might be expected changes to response amplitudes although significant were small. The diagnostically best protocol produced the largest effect of IOLs on pupil constriction: a response reduction of -0.33 dB, tstat = 7.27, p = 3.66e-13.
Conclusions: :
This study of 328 eyes demonstrates that IOLs have only a small effect on pupillary responses and diagnostic performance in glaucoma subjects and that this can be compensated for by a small bias term on the normative data of about 0.3 dB.
Keywords: perimetry • pupil • refractive surgery: phakic IOL