Long-term progression of visual field defects and related factors in medically treated normal tension glaucoma

Figures & data

Table 1 Patient characteristics, IOP data, and visual field data

Characteristics	n (%)	Mean ± SD
Sex
Female	82 (61.2)
Male	52 (38.8)
Age (years)		57.7±11.3
Follow-up period (years)		8.05±0.82
Refractive error (D)		−3.19±3.56
CCT (μm)		520.5±32.7
DH
+	29 (21.6)
−	105 (78.4)
Baseline IOP (mmHg)		14.96±1.98
Mean IOP (mmHg)		12.01±0.88
IOP reduction rate (%)		18.82±8.48
IOP reduction range (mmHg)		−2.95±1.60
Maximum IOP (mmHg)		14.32±1.63
Minimum IOP (mmHg)		10.29±0.98
IOP range (mmHg)		4.03±1.27
IOP fluctuation (mmHg)		0.97±0.22
Initial MD value (dB)		−7.46±5.53
Final MD value (dB)		−10.35±6.49
MD slope (dB/yr)		−0.22±0.22

Notes: Mean ± SD number of visual field tests: 15.7±3.6 (range, 11–29). Mean ± SD number of IOP measurements: 37.8±4.4 (range, 23–41).

Abbreviations: CCT, central corneal thickness; DH, disc hemorrhage; IOP, intraocular pressure; MD, mean deviation; SD, standard deviation.

Figure 1 Distribution of number of eyes in which consecutive decrease in MD value was observed.

Notes: Of 130 eyes in which consecutive decrease in MD value was observed during the follow-up period, the number of two consecutive was 57 eyes (43.8%). Three consecutive and four or more consecutive was observed in 39 eyes (30.0%) and 34 eyes (26.2%), respectively.
Abbreviation: MD, mean deviation.

Figure 2 Distribution of number of eyes with MD slope value at the final visual field test.

Notes: At the final visual field test, significantly negative MD slope was observed in 80 (59.7%: red column) of 134 eyes, but MD slope deterioration was not significant in 54 eyes (40.3%: blue column). All 21 eyes with MD slope of lower than −0.4 dB/year showed significant deterioration. Of 102 eyes with MD slope was less than −0.4 dB/year, however, 59 eyes (57.8%) appeared to be significant MD slope deterioration.
Abbreviation: MD, mean deviation.

Table 2 Results of trend analysis and univariate logistic regression analysis

Consecutive decrease of MD	MD slope		Total
	Deterioration	Nondeterioration	n (%)
	n (%)	n (%)
≤1	2 (50.0)	2 (50.0)	4 (3.0)
2	23 (40.4)	34 (59.6)	57 (42.5)
3	26 (66.7)	13 (33.3)	39 (29.1)
≥4	29 (85.3)	5 (14.7)	34 (25.4)
Total	80 (59.7)	54 (40.3)	134
			P-value: <0.0001
Value	Odds ratio (95% CI)		P-value
Consecutive decrease of MD	2.19 (1.44–3.34)		<0.0001

Notes: Objective variable: presence or absence of MD slope deterioration. Explanatory variables: consecutive deterioration of VFD.

Abbreviations: CI, confidence interval; IOP, intraocular pressure; MD, mean deviation; VFD, visual field defects.

Table 3 Comparison of variables between groups with and without MD slope deterioration

Factor	MD slope		P-valuea
	Deterioration	Nondeterioration
	(n=80)	(n=54)
Sex n (%)			0.4755
Female	51 (63.8)	31 (57.4)
Male	29 (36.2)	23 (42.6)
Age (years)	57.6±10.88	57.9±11.95	0.8943
Follow-up duration (years)	8.0±0.81	8.0±0.86	0.9792
Refractive error (D)	−3.2±3.31	−3.2±3.92	0.9410
CCT (μm)	518.5±31.31	523.5±34.84	0.3935
DH, n (%)			0.5265
+	19 (23.8)	10 (18.5)
−	61 (76.2)	44 (81.5)
Baseline IOP (mmHg)	14.7±1.95	15.3±1.99	0.0896
Mean IOP (mmHg)	12.0±0.85	12.0±0.92	0.5307
IOP reduction rate (%)	17.2±8.64	21.2±7.68	0.0053*
IOP reduction range (mmHg)	−2.67±1.59	−3.37±1.54	0.0130*
Maximum IOP (mmHg)	14.3±1.54	14.4±1.76	0.7797
Minimum IOP (mmHg)	10.3±0.93	10.4±1.05	0.5660
IOP range (mmHg)	4.0±1.24	4.0±1.34	0.9340
IOP fluctuation (mmHg)	1.0±0.21	1.0±0.24	0.5765
Initial MD value (dB)	−7.1±5.61	−8.0±5.43	0.3950
Final MD value (dB)	−11.8±6.61	−8.3±5.77	0.0016*
MD slope (dB/yr)	−0.32±0.20	−0.06±0.12	<0.000*

Notes:

a Welch’s t-test except sex, DH (Fisher’s exact test);

* Values indicate those results that are statistically significant at the P<0.05 level.

Abbreviations: CCT, central corneal thickness; DH, disc hemorrhage; IOP, intraocular pressure; MD, mean deviation; SD, standard deviation.

Table 4 Results of multivariate logistic regression analysis

Value	Odds ratio (95% CI)	P-value
Consecutive decrease of MD	2.43 (1.55–3.80)	<0.0001
IOP reduction rate (%)	0.92 (0.88–0.97)	0.0020

Notes: Objective variable: presence or absence of MD slope deterioration. Explanatory variables: consecutive deterioration of VFD, IOP reduction rate versus baseline.

Abbreviations: CI, confidence interval; IOP, intraocular pressure; MD, mean deviation; VFD, visual field defects.