A FBGC reaction may follow implantation of the tarSys™ xenograft.

No abstract

The laser interferometer can effectively bypass the optics of the eye and measure retinal function in patients with immature cataracts. However, it is not known how much laser interferometric measurements are impaired by cataract density. In this study we compared objective lens opacity using the IntraOptics opacity lensmeter with contrast sensitivity (CS) measured by a Randwal He-Ne laser interferometer. Comparison of lens opacity with CS in the cataract population revealed an inverse linear relationship between objective lens opacity and retinal contrast sensitivity. Separation by cataract type showed correlation coefficients as high as -0.91 for nuclear sclerotic predominant cataracts and as low as no significant correlation for posterior subcapsular predominant cataracts. Comparisons of before and after implantation surgery contrast sensitivities (as measured by the laser interferometer) with preoperative lens opacities (as measured by the IntraOptics opacity lensmeter) quantified the extent to which laser interferometric measurements underestimated potential retinal function. We found that for all cataracts, other than posterior subcapsular predominant cataracts, potential contrast sensitivity (in decibels) was underestimated by about 0.2 to 0.3 times the opacity measured by this technique.

Preoperative contrast sensitivity functions (CSFs) were determined for 15 cataract patients using laser-generated patterns that effectively bypassed the optical components of the eye. These functions were compared with postoperative CSFs determined using traditional methods by transmission through the optics of the eye. Accurate prediction of postoperative contrast sensitivity occurred in 91% of the cases (ten of 11) for patients with preoperative visual acuity of 20/200 or better and in 67% of all the cases (ten of 15). Prediction failures occurred when the laser interferometer was not able to penetrate the cataract or when postoperative complications occurred. These results suggest that preoperative measurement of laser interferometric CSF is a useful predictor of postoperative CSF for patients with mild to moderate cataracts that can be bypassed by the laser and with better than 20/200 preoperative visual acuity. The problem of assessment when lens opacity is advanced is addressed in Part II.