Comparison of methods to assess visual impairment from glare and light scattering with posterior capsule opacification

Purpose: To compare 2 glare tests to determine their relative usefulness in the assessment of posterior capsule opacification (PCO) and to evaluate th e potential benefits of combined visual acuity, contrast sensitivity, and g lare testing. Setting: Teaching hospital ophthalmology department. Methods: Sixteen patients had glare, visual acuity, and contrast sensitivit y testing before and after neodymium:YAG (Nd:YAG] capsulotomy. Results with the Brightness Acuity Tester (BAT, Mentor), which measures disability glar e, and the Straylightmeter (Foundation for Eye Research, The Netherlands). which quantifies forward scatter by direct compensation techniques, were co mpared. The correlation between glare, ETDRS visual acuity, and Pelli-Robso n contrast sensitivity was determined. Results: Pretreatment visual acuity was significantly correlated with contr ast sensitivity (P <.01). However, visual acuity and contrast sensitivity w ere poorly correlated with both the BAT and Straylightmeter (P >.05), indic ating that visual acuity is predictive of contrast sensitivity but a poor p redictor of glare. Glare was significantly improved (Straylightmeter, P<.00 01; BAT, P <.05) following capsulotomy, While the Straylightmeter consisten tly measured precapsulotomy forward scatter that improved with treatment, c orresponding BAT disability glare was unmeasurable in 18.8% of patients wit h PCO, as their visual acuities improved rather than deteriorated with glar e testing. Conclusions. Glare testing provided more information than contrast sensitiv ity when combined with visual acuity in the evaluation of PCO. Glare relate d to PCO is better assessed using the Straylightmeter because the BAT may y ield aberrant disability glare results.