Efficacy of the Amsler Grid Test in Evaluating Glaucomatous Central Visual Field Defects.

ABSTRACT

PURPOSE: To investigate the efficacy of the Amsler grid test in detecting central visual field (VF) defects in glaucoma. DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Patients with glaucoma with reliable Humphrey 10-2 Swedish Interactive Threshold Algorithm standard VF on the date of enrollment or within the previous 3 months. METHODS: Amsler grid tests were performed for each eye and were considered "abnormal" if there was any perceived scotoma with missing or blurry grid lines within the central 10 degrees ("Amsler grid scotoma"). An abnormal 10-2 VF was defined as ≥3 adjacent points at P < 0.01 with at least 1 point at P < 0.005 in the same hemifield on the pattern deviation plot. Sensitivity, specificity, and positive and negative predictive values of the Amsler grid scotoma area were calculated with the 10-2 VF as the clinical reference standard. Among eyes with an abnormal 10-2 VF, regression analyses were performed between the Amsler grid scotoma area and the 10-2 VF parameters (mean deviation [MD], scotoma extent [number of test points with P < 0.01 in total deviation map] and scotoma mean depth [mean sensitivity of test points with P < 0.01 in total deviation map]). MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of the Amsler grid scotoma area. RESULTS: A total of 106 eyes (53 patients) were included (mean ± standard deviation age, 24-2 MD and 10-2 MD = 66±12 years, -9.61±8.64 decibels [dB] and -9.75±9.00 dB, respectively). Sensitivity, specificity, and positive and negative predictive values of the Amsler grid test were 68%, 92%, 97%, and 46%, respectively. Sensitivity was 40% in eyes with 10-2 MD better than -6 dB, 58% in eyes with 10-2 MD between -12 and -6 dB, and 92% in eyes with 10-2 MD worse than -12 dB. The area under the receiver operating characteristic curve of the Amsler grid scotoma area was 0.810 (95% confidence interval, 0.723-0.880, P < 0.001). The Amsler grid scotoma area had the strongest relationship with 10-2 MD (quadratic R(2)=0.681), followed by 10-2 scotoma extent (quadratic R(2)=0.611) and 10-2 scotoma mean depth (quadratic R(2)=0.299) (all P < 0.001). CONCLUSIONS: The Amsler grid can be used to screen for moderate to severe central vision loss from glaucoma.