Abstract
Purpose: :
Patients with retinal diseases are known to have sensitivity to the effects of light on quality of vision measured. As such, the effects of diagnostic testing and the light utilized in these tests could negatively affect visual acuity measurements and result in the inappropriate or incorrect application of repeat intravitreal treatment. The goal of the study is to determine the effects of these tests on visual acuity and assist clinicians in the developing a rigorous visual acuity protocol for testing to ensure that high quality decisions are made.
Methods: :
A consecutive series of patients taken from tertiary retinal practices of three vitreo-retinal surgeons who underwent diagnostic testing for macular disease(s) were selected. Patients underwent visual acuity evaluation on a standardized snellen chart. This first visual acuity evaluation took place prior to the instillation of dilating drops required for the performance of diagnostic testing such as intravenous fluorescein angiography (IVFA), Optical Coherence Tomography (OCT) or both. Dilation with a standard phenylephrine/tropicamide mixture was used. Visual acuity was repeated utilizing the same Snellen chart 10 to 15 minutes following the diagnostic procedures. Patients were divided into clinical subgroups based on why they were having diagnostic testing performed. Groups included: dry ARMD, wet ARMD, diabetic retinopathy, and other.
Results: :
Total patients in the study were 172, which equaled a total of 344 eyes. Mean age of patients was 76.47 yrs ± 11.70. Mean time from completing diagnostic test to final BCVA measurement was 18.40 mins ± 3.23. The mean initial BCVA prior to diagnostic testing was 20/95. The mean BCVA after diagnostic testing was 20/115, this resulted in a 0.083 log Mar unit decrease in BCVA after diagnostic testing. There was a statistically significant decline in visual acuity after diagnostic testing in all three clinical subgroups: dry ARMD (p<0.003), wet ARMD (p0.001). Both age (odds ratio=5.92) and initial visual acuity prior to diagnostic testing (odds ratio=2.99) were found to be independent predictors for significant decline in vision after a diagnostic test.
Conclusions: :
Consider effects of diagnostic testing on visual acuity in patients who are older and have poor initial visual acuity. Complete visual acuity testing prior to diagnostic testing as it offers better representation of actual visual acuity. May consider effects of diagnostic testing on visual acuity for patients who are chronically followed for re-treatment regimes with Anti-VEGF.
Keywords: retina • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual acuity