Table 1: Binocular visual acuity (BVA) and binocular summation (BS) of BVA in the group A (patients with central retinal impairment) with prismatic and non-prismatic correction after the entry examination and after 30-day trial wearing. The bold marked pairs (prism vs. non-prism) vary at statistically significant level p < 0.05 (column „Wilcoxon test results). Number behind BVA and BS signs the Weber’s contrast level; „total“ =  sum of ETDRS letters, correctly read at all contrast levels. 

Group A. binocular visual acuity (BVA) and summation (BS)

After examination

Mean values | Standard deviations

Wilcoxon test results (p)

At a distance

(number of ETDRS letters)

Prism

Non-prism

Difference

BVA (full contrast)

80.588

12.679

79.412

11.336

1.176

3.695

0.167

BVA (50% contrast)

77.706

12.348

77.412

12.947

0.294

1.929

0.529

BVA (25% contrast)

73.941

13.836

71.294

14.451

2.647

4.315

0.032

BVA (10% contrast)

60.824

15.163

59.059

15.762

1.765

2.969

0.023

BVA (sum of all contrast levels)

293.059

52.996

287.176

52.551

5.882

7.817

0.006

BS (full contrast)

0.529

2.875

-0.647

4.212

1.176

3.695

0.167

BS (50% contrast)

0.941

3.191

0.647

3.161

0.294

1.929

0.529

BS (25% contrast)

1.412

3.374

-1.235

5.847

2.647

4.315

0.032

BS (10% contrast)

3.353

3.823

1.588

3.447

1.765

2.969

0.023

BS (sum of all contrast levels)

6.235

8.166

0.353

13.048

5.882

7.817

0.006

At near distances (decimal)

 

 

 

 

 

 

 

BVA

0.871

0.229

0.821

0.237

0.050

0.269

0.012

BS

0.032

0.058

-0.027

0.059

0.059

0.081

0.012

After 30-day trial wearing

Mean values | Standard deviations

Wilcoxon test results (p)

At a distance

(number of ETDRS letters)

Prism

Non-prism

Difference

BVA (full contrast)

80.647

11.816

79.353

12.257

1.294

3.312

0.132

BVA (50% contrast)

77.529

12.625

77.059

13.021

0.471

4.732

0.950

BVA (25% contrast)

72.941

12.765

71.471

13.125

1.471

3.955

0.088

BVA (10% contrast)

56.882

15.341

57.118

15.194

-0.235

6.006

0.938

BVA (sum of all contrast levels)

288.000

51.116

285.000

52.709

3.000

13.143

0.332

BS (full contrast)

1.000

2.806

0.000

3.041

1.000

4.213

0.320

BS (50% contrast)

0.882

4.729

-0.647

4.795

1.529

5.680

0.414

BS (25% contrast)

1.529

3.955

-0.529

4.361

2.059

4.867

0.093

BS (10% contrast)

1.765

8.318

0.529

4.033

1.235

6.969

0.421

BS (sum of all contrast levels)

5.176

16.576

-0.647

13.852

5.824

14.943

0.326

At near distances (decimal)

 

 

 

 

 

 

 

BVA

0.858

0.245

0.818

0.261

0.040

0.075

0.076

BS

0.048

0.085

-0.003

0.066

0.051

0.074

0.028