Abstract
Purpose::
Diabetic eye screening at Nashville VAMC is performed by the Vanderbilt Ophthalmic Imaging Center (VOIC.) VOIC protocol includes mydriatic digital fundus photographs and visual acuity testing. The purpose of this study was to determine how well visual acuity measurements taken via VOIC protocol correlate with those measured in the eye clinic. A secondary aim was to determine if these data are predictive of eye disease not detected in the digital fundus photograph.
Methods::
483 patients were screened using VOIC protocol from January 2, 2004 to December 22, 2004. Of this group, 204 patients were referred exclusively for a diagnosis of decreased visual acuity (<20/40) in one or both eyes. These patients were sorted alphabetically, and a convenience sample of the final 75 consecutive records was chosen. Of these, 68 charts were available for review. The following elements were recorded from the eye clinic visit: date, spectacle use, entering visual acuity, etiology of decreased vision, presence or absence of diabetic retinopathy, and severity of diabetic retinopathy. If visual acuity data were not present in the chart or if visual acuity could not be quantified, the data were excluded. Visual acuity in 82 eyes of 43 patients was converted to logMAR notation and compared.
Results::
Of the 68 charts reviewed, 48 patients followed up in the eye clinic, and their visual acuity measured in the eye clinic correlated well (ρ = 0.745) to the VOIC data. The most common reasons for decreased visual acuity were uncorrected refractive error (35.7%), false-positive on screening (23.2%), cataract (10.7%), and amblyopia (8.9%). Combined mechanisms of decreased vision (visual acuity plus other ocular pathology) accounted for 10.7% of patients. The remaining etiologies were functional vision loss, known retinal or optic nerve pathology, and known glaucoma. Presence or absence of diabetic retinopathy as determined by VOIC and by the eye clinic examiner agreed in 85% of cases. No patient was found to have severity of disease greater than mild non-proliferative diabetic retinopathy, and none of the patients had decreased visual acuity secondary to diabetic retinopathy.
Conclusions::
A significant proportion of patients were referred (42.2%) solely because of decreased visual acuity, yet no patient was found to have decreased visual acuity due to diabetic retinopathy. VOIC visual acuity data correlates well with clinical measures and seems useful for detecting eye and vision problems unrelated to diabetic retinopathy.
Keywords: visual acuity • diabetic retinopathy