Comparing a Home Vision Self-Assessment Test to Office-Based Snellen Visual Acuity

Figures & data

Table 1 Patient and Ocular Characteristics

Patient Characteristics (Total Patients N=45)	Values
Female, N (%)	19 (42%)
Age (years), mean (SD)	66 (16)
Both Eyes Included in Study, N (%)	37 (82%)
Single Eye Included in Study, N (%)	8 (18%)
Right eye	5 (11%)
Left eye	3 (7%)
Ocular Conditions Present	Study eyes (N =45)	Fellow Eyes (N =42)
Glaucoma, N (%)	34 (79%)	31 (79%)
Glaucoma suspect, N (%)	9 (21%)	8 (21%)
Lens Status
Phakic, N (%)	30 (67%)	24 (59%)
Pseudophakic, N (%)	15 (33%)	17 (41%)
Myopia, N (%)	8 (18%)	8 (19%)
Uveitis, N (%)	5 (11%)	5 (12%)
Age-Related Macular Degeneration, N (%)	1 (2%)	1 (2%)

Abbreviations: N, number; SD, standard deviation.

Table 2 Comparison of logMAR Visual Acuity Scores

Group	N	Visual Acuity (logMAR)
		Office (Mean, SD)	Home (Mean, SD)	Difference (Office – Home) (Mean, SD)	P-value
Study Eyes	45	0.15 (0.16)	0.17 (0.18)	−0.02 (0.15)	0.28
Vision Better than or equal to 20/40 (logMAR ≤ 0.3)*	38	0.10 (0.11)	0.15 (0.14)	−0.05 (0.13)	0.01
Vision Worse than 20/40 (logMAR > 0.3)*	7	0.43 (0.08)	0.30 (0.19)	0.13 (0.17)	0.09
Fellow Eyes	42	0.15 (0.17)	0.17 (0.20)	−0.02 (0.15)	0.32
Vision Better than or equal to 20/40 (logMAR ≤ 0.3)*	38	0.11 (0.11)	0.15 (0.15)	−0.04 (0.12)	0.04
Vision Worse than 20/40 (logMAR > 0.3)*	4	0.56 (0.13)	0.43 (0.38)	0.14 (0.30)	0.44

Note: *Grouping based on office visual acuity score.

Abbreviations: N, number; SD, standard deviation; logMAR, logarithm of the Minimal Angle of Resolution.

Figure 1 Scatterplot of Office versus Home Visual Acuity.

Notes: Visual acuity measured in the office and at home, with the line of equality; Points have been jittered to help with visualization.

Abbreviations: VA, visual acuity; logMAR, logarithm of the Minimal Angle of Resolution.

Figure 2 Bland-Altman Plot of Office versus Home Visual Acuity.

Notes: Bland-Altman plots of the difference between office and home visual acuity (VA) assessments versus the mean of office and home VA assessments for (A) Study eyes (N=45) and (B) Fellow eyes (N=42). The dashed center line indicates the mean difference and the dashed upper and lower lines indicate the 95% limits of agreement. Shaded regions represent the clinically acceptable limits of agreement, ± 0.2 logMAR from the mean difference. Counts demonstrate number of eyes at each point.

Abbreviations: N, number; logMAR, logarithm of the Minimal Angle of Resolution.