Pain responses of Pascal 20 ms multi-spot and 100 ms single-spot panretinal photocoagulation: Manchester Pascal Study, MAPASS report 2.
OBJECTIVE
To evaluate pain responses following Pascal 20 ms multi-spot and 100 ms single-spot panretinal photocoagulation (PRP).


METHODS
Single-centre randomised clinical trial. 40 eyes of 24 patients with treatment-naive proliferative diabetic retinopathy randomised to 20 and 100 ms PRP under topical 0.4% oxybuprocaine. A masked grader used a pain questionnaire within 1 h (numerical pain score (NPS)) and 1 month after treatment (numerical headache score (NHS)). Primary outcome measure was NPS immediately post-PRP. Secondary outcome measures were mean NHS scores and levels of photophobia reported within 4 weeks of primary PRP.


RESULTS
Mean laser fluence was significantly lower using 20 ms PRP (4.8 J/cm²) compared to 100 ms PRP (11.8 J/cm²); p < 0.001). Mean NPS scores for treatment were 2.4 (2.3) (mild) for 20 ms PRP group compared to 4.9 (3.3) (moderate) in 100 ms PRP group-a significant difference (95% CI 4.3 to 0.68; p = 0.006). Mean NHS score within 1 month was 1.5 (2.7) in 20 ms PRP group compared to 3.2 (3.5) in the 100 ms PRP group (p < 0.05). The median duration of photophobia after 20 ms PRP was 3 h, and significantly less compared to 100 ms PRP after which 72 h of photophobia was reported (p < 0.001).


CONCLUSIONS
Multi-spot 20 ms PRP was associated with significantly lower levels of anxiety, headache, pain and photophobia compared to 100 ms single-spot PRP treatment. Possible reasons include lower fluence, shorter-pulse duration, and spatial summation of laser nociception with multi-spot Pascal technique.
Muqit
M M K
MM
Manchester Royal Eye Hospital, Manchester, UK.
Marcellino
G R
GR
Gray
J C B
JC
McLauchlan
R
R
Henson
D B
DB
Young
L B
LB
Patton
N
N
Charles
S J
SJ
Turner
G S
GS
Stanga
P E
PE
D000287:Administration, Topical; D000779:Anesthetics, Local / Q000008:administration & dosage*; D003930:Diabetic Retinopathy / Q000601:surgery*; D005260:Female; D006801:Humans; D008028:Light Coagulation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000209:etiology* / Q000517:prevention & control; D020795:Photophobia / Q000209:etiology; D011343:Procaine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D011446:Prospective Studies; D018630:Vitreoretinopathy, Proliferative / Q000601:surgery*
D000779:Anesthetics, Local; D011343:Procaine; C005298:benoxinate