Dysfunctional Pain Coping Features in Neuropathic Corneal Pain

Abstract

Purpose : Catastrophic thinking related to pain might be a risk factor for high levels of pain, emotional distress and chronicity. Our purpose is to assess pain coping mechanisms in patients with neuropathic corneal pain (NCP) by pain catastrophizing scale (PCS).

Methods : Medical records of patients who were diagnosed with NCP or DED, based on clinical and in vivo corneal confocal microscopic findings, and filled out the PCS questionnaire were evaluated retrospectively (n=111). The PCS asks about 13 thoughts or feelings during pain experience which yield a total score (0-52) and 3 subscores assessing rumination (0-16), magnification (0-12) and helplessness (0-24). Individuals whose total PCS score/subscores are higher than 50^th percentile of asymptomatic samples are considered at moderate/high risk for the development of chronicity. NCP patients were subcategorized based on proparacaine challenge test as followings: pure peripheral NCP (P-NCP); complete pain relief after drop; mixed mechanism NCP (M-NCP); partial pain relief after drop, and pure central NCP (C-NCP); no pain relief after drop. ANOVA analysis was used to compare differences between groups.

Results : Thirty-one P-NCP patients, 38 M-NCP patients, 22 C-NCP patients and 20 DED patients were included. The mean age of patients was 54.0±16.5 in P-NCP, 48.8±18.0 in M-NCP, 50.4±15.7 in C-NCP and 46.5±17.4 in DED (p=0.29). The mean total PCS score was 20.5±15.0 (0-52) in NCP and 8.5±12.8 (0-46) in DED (p=0.001). The mean rumination (7.3±5.6 vs. 3.6±5.4), magnification (3.9±3.3 vs. 1.6±2.5) and helplessness (9.3±7.3 vs.3.2±5.6) subscores were higher in NCP compared to DED (p<0.05). The mean total PCS score was lower in P-NCP (14.1±13.2) compared to M-NCP (24.4±15.0) (p=0.005) and C-NCP (23.2±15.0) (p=0.02). Rumination (5.3±5.0 vs. 8.5±5.8 vs. 8.4±5.4) and helplessness (5.3±5.7 vs. 12.3±7.2 vs. 9.9±7.2) subscores were lower in P-NCP group compared to M-NCP (p=0.02) and C-NCP (p=0.05), respectively. However, the magnification subscore (3.4±3.6 vs. 4.1±3.3 vs. 4.3±3.0) was similar in all NCP groups (p=0.55).

Conclusions : Neuropathic corneal pain patients exhibit dysfunctional pain coping mechanisms and NCP patients with central component (both M-NCP and C-NCP) are more affected than P-NCP. Therefore, NCP patients with central component need more close and meticulous attention, since they have a higher risk of development of persistent pain and emotional distress.

This is a 2020 ARVO Annual Meeting abstract.