Abstract
Purpose::
To determine If pseudoexfoliation (PXF) is associated with increased mortality and progression of lens opacities.
Methods::
In 1999, 833 volunteer participants aged >=50 years underwent full slit lamp examination including Goldmann intraocular pressure,LOCS III grading for lens opacity, optic disc assessment and photography. At follow up, 168/833 (20.2%) had died, and 346/665 (52.0%) of the remaining participants were traced and re-examined using similar methods.Progression of lens opacity was identified as an increase of LOCSIII grades beyond a threshold derived from the inter-observer variation tests. This was a change of 1.0 LOCSIII units for nuclear opacity (NO), colour (NC), and posterior subcapsular lens opacity (PSCLO), and 1.5 units for cortical lens opacity (CLO). The effect of PXF, age and gender on mortality and cataract progression opacity was assessed using the chi squared test, t-test or the Wilcoxon rank sum test. The presence of climatic droplet keratopathy (CDK) was used as a proxy indicator for ultraviolet (UV) exposure in the final model. Differences in baseline cup-disc ratio (CDR) between subjects who did and did not attend for re-examination were analysed to assess the effect of bias on the results.
Results::
At baseline, 62/833 participants were diagnosed with PXF (7.4%, 95% CI, 6.5-8.3). 24.2% of those diagnosed with PXF at baseline had died compared to 19.3% without PXF (Odds Ratio(OR)=1.33, 0.72-2.45, p=0.35, age-adjusted OR=0.8, 0.4-1.9, p=0.6). Progression of NO was identified in 48/315 participants (15.2%; 13.2-17.2%), NC in 47 participants (15.1%; 13.1 -17.1%), CLO in 67 participants (21.9%; 19.6-24.2%) and PSCLO in 10 participants (3.3%; 2.3-4.3%). Participants with PXF were more likely to have progression of lens opacity; for NO, OR=1.7, 0.6-4.9, p=0.3; for NC, OR=1.35, 0.4-4.2, p=0.6; CLO, OR= 2.0, 0.8-5.3, p=0.1; for PSCLO, OR=4.3, 0.8-22.3, p=0.06, although none of these effects were statistically significant. The OR for the effect of PXF on progression was attenuated by inclusion of age and gender. Inclusion of CDK had no effects on the final model. There was no difference in median CDR between those examined and not re-examined (0.3, IQR: 0.2-0.4 in both groups,p=0.49).
Conclusions::
There is no evidence from this cohort that PXF is associated with increased mortality or progression of lens opacity.
Keywords: cataract • clinical (human) or epidemiologic studies: natural history