Table 1 Summary of characteristics of the included studies

Blaha et al. [16] (USA)

To compare pain scores during injection versus total procedure for four anesthetic techniques

96

80

G1: 0.5% topical proparacaine

Pain was graded on a 0 to 10 scale

RNZ, BVZ

G1: 3.0

No statistical difference in pain scores for the four anesthetic techniques. Topical drops provided excellent anesthesia in a quick, comfortable, and safe manner for IVI

G2: 0.5% topical tetracaine

G2: 2.8

G3: topical proparacaine + 4% lidocaine pledget

G3: 2.3

G4: topical proparacaine + SC injection of 2% lidocaine

G4: 3.1

p = 0.28

Yau et al. [11] (Canada)

To compare the anesthetic effectiveness of three topical agents used for IVIs

93

Group 1: 83.6

G1: 0.5% tetracaine hydrochloride drops + 4% lidocaine pledget for 10

Patients graded pain on a 100-mm VAS, or by saying a number from 0 to 100

RNZ

G1: 19 (12–26)

No clinical (statistical) difference in patient pain between the three topical agents tested. The addition of a 4% lidocaine pledget for 10” offered no clinical advantage in pain relief compared to 0.5% tetracaine or 4% cocaine drops alone

Group 2: 79.5

G2: 0.5% tetracaine hydrochloride drops

G2: 21 (13–29)

Group 3: 82.1

G3: 4% cocaine + epinephrine 1/100.000 drops

G3: 21 (16–27)

Örnek et al. [14] (Turkey)

To compare the efficacy of topical 0.75% levobupivacaine and 0.5% proparacaine

96

63.97

G1: 0.75% levobupivacaine drops

Patients graded pain on a 100-mm VAS

RNZ, TAC

G1: 44.77 ± 16.42

0.5% topical proparacaine was more effective than 0.75% topical levobupivacaine in preventing pain during IVI

G2: 0.5% proparacaine drops

G2: 34.18 ± 14.83

p = 0.003

Shiroma et al. [1] (Brazil)

To investigate the safety and anesthetic efficacy of five concentrations of lidocaine gel

260

70.1

G1: 2% lidocaine gel

Patients graded pain on a 0 to 10 scale

RNZ

G1: 2.63 ± 1.68

Lidocaine gel at concentrations from 2% to 12% induced similar anesthetic effect for IVI

G2: 3.5% lidocaine gel

G2: 2.08 ± 1.35

G3: 5% lidocaine gel

G3: 2.00 ± 1.65

G4: 8% lidocaine gel

G4: 1.93 ± 1.40

G5: 12% lidocaine gel

G5: 1.83 ± 1.35

p = 0.077

Andrade et al. [6] (Brazil)

To compare the anesthetic effectiveness of topical proparacaine drops, SC lidocaine, and 2% lidocaine gel

92

66.4

G1: proparacaine

Patients graded pain on a 0 to 10 scale

BVZ

G1: 3.2 ± 1.7

SC injection of lidocaine was most effective in preventing pain during IVI compared to proparacaine or 2% lidocaine gel

G2: proparacaine + SC injection of 2% lidocaine

G2: 1.0 ± 1.0

G3: 2% lidocaine gel

G3: 1.0 ± 1.1

Kumar et al. [15] (UK)

To compare patient comfort during IVI after SC anesthesia or topical eye drops

30

G1: 72

G1: 0.5% proximetacaine

Patients graded pain on a 0 to 10 scale

TAC

G1: 0.87 ± 0.83

There was no significant difference in pain scores or overall satisfaction scores between the two groups

G2: 74

G2: SC injection of 2% lidocaine

G2: 0.93 ± 0.96

p = 0.84

Davis et al. [2] (USA)

To compare the anesthetic effect among topical proparacaine drops, 4% lidocaine solution, and 3.5% lidocaine gel

120

80.18

G1: 0.5% topical proparacaine

Patients graded pain on a 0 to 10 scale

BVZ, RNZ, TAC

G1: 1.78 ± 1.44

There was no significant difference in pain scores or overall satisfaction scores between the different groups

G2: topical proparacaine + 4% lidocaine pledget

G2: 1.75 ± 1.46

G3: 3.5% lidocaine gel

G3: 1.48 ± 1.58

p = 0.38

Rifkin and Schaal [5] (USA)

To determine factors associated with patient comfort during in-office IVI

60

65

G1: 0.5% TetraVisc

Patients graded pain on a 0 to 10 scale

BVZ, RNZ, TAC

G1: 3.39 ± 2.26

The tetracaine group reported the lowest pain

G2: proparacaine

G2: 3.17 ± 2.18

G3: tetracaine

G3: 3.05 ± 2.01

p < 0.01