The effect of cold tetracaine on the severity of burning sensation upon instillation

Figures & data

Table 1 Demographic characteristics of the study population

	Total number of subjects (N=424)
Age, mean±SD
Gender, n (%)
Female	219 (51.7)
Male	205 (48.3)
History of surgery, n (%)
No	280 (66)
Yes	144 (34)
Hypertension, n (%)	222 (52.4)
Diabetic mellitus, n (%)	199 (46.9)
Dry eye disease, n (%)
No	287 (67.7)
Yes	137 (32.3)
Glaucoma, n (%)
No	375 (88.4)
Yes	49 (11.6)

Figure 1 Comparison of mean VAS scores of the symptoms between instillation of cold tetracaine vs room temperature tetracaine.

Note: The VAS burning sensation score of cold tetracaine was significantly lower than that of room temperature solution (P-value 0.025).
Abbreviation: VAS, visual analog scale.

Table 2 Subgroups of patients and VAS score of burning sensation at room temperature (independent sample t-test)

	n	VAS score of burning sensation (mean±SD)	P-value
Age, years
≤40	49	23.4±19.3	0.241
>40	375	20.1±18.7
Gender
Male	205	20.5±18.7	0.111
Female	219	22.6±20.1
Corneal sensation
C-BA >3 cm (normal)	102	25.8±20.2	0.011*
C-BA ≥3 cm (impaired)	183	21.4±19.1
Tetracaine used in the previous year
Yes	242	19.4±18.1	<0.001*
No	137	24.8±11.3
History of ocular surgery
Yes	143	19.1±18.0	0.008*
No	277	22.7±20.0
Dry eye disease
Yes	137	21.0±18.5	0.124
No	287	22.6±19.7
Glaucoma
Yes	49	21.0±19.8	0.751
No	375	21.6±19.4
Diabetic retinopathy
Yes	82	17.3±17.1	0.163
No	342	20.9±19.2

Note:

* P<0.05.

Abbreviations: C-BA, Cochet–Bonnet esthesiometer; VAS, visual analog scale.

Table 3 Comparison of burning sensation assessed by VAS score between cold tetracaine and room temperature tetracaine in different subgroups (paired t-test, α=0.05)

Demographic data	Burning sensation VAS score (mm)			P-value
	n	Cold tetracaine (mean±SD)	Room temperature tetracaine (mean±SD)
Age, years
≤40	49	23.5±19.3	35.7±24.3	<0.001
>40	375	20.1±18.71	20.9±18.7	0.415
Gender
Male	205	20.2±18.0	20.8±19.4	0.695
Female	219	20.8±19.6	24.5±20.5	0.007
Corneal sensation, cm
>3	102	23.8±19.1	28.1±21.4	0.009
≤3	183	20.7±18.5	21.8±19.2	0.57
Tetracaine used in the previous year
First-time user	137	21.9±20.7	27.9±21.7	0.001
More than one time user	242	19.7±18.3	19.2±17.9	0.676
History of ocular surgery
No	277	21.1±19.4	24.4±20.6	0.006
Yes	143	19.1±17.5	19.0±18.5	0.949
Dry eye disease	137	18.5±19.5	22.7±20.9	0.08
Diabetic retinopathy
No	342	21.3±19.1	23.9±20.6	0.076
Yes	82	17.2±17.1	17.1±17.5	0.973

Abbreviation: VAS, visual analog scale.