Functional visual acuity measurement in cataract and intraocular lens implantation

Recently, functional visual acuity (FVA) measurement has been reported to be an important method of determining 'masked impairment of visual function' and assessing visual acuity in detail. This review discusses a new continuous FVA measurement system for the assessment of visual performance and introduces the application of FVA measurement in cataract and intraocular lens implantation.

The FVA was first developed to detect impaired visual function for daily activities in dry eye syndrome. The usefulness of this new methodology has been described in patients with tear instability, undergoing laser-assisted in-situ keratomileusis surgery, with Stevens-Johnson syndrome, Sjögren syndrome and mild cataract opacities. The microstructure of the lenticular opacities is highly variable (nucleus sclerosis and/or posterior capsular cataract and/or cortical opacity) causing a combination of different effects on the incident light rays that can be refracted, reflected, absorbed or scattered. In some cases, patients have a good visual acuity but may complain of disturbances in vision quality. We reported the improvement of FVA after cataract surgery in patients with mild cataracts and visual symptomatology despite a good preoperative and postoperative conventional visual acuity. To detect visual impairment due to cataract, measurement of FVA was useful in the evaluation of vision quality and changes in kinetic vision after phacoemulsification surgery.

FVA measurement is an effective and noninvasive test that reflects the complaints of blurring/glare and postoperative satisfaction in patients with mild cataract.