Evaluation of Corneal Biomechanical Parameters in Psoriasis Patients: A Controlled Study

Abstract

Purpose: To evaluate corneal biomechanical parameters with an ocular response analyzer (ORA) in patients with psoriasis and compare these parameters with age-matched control subjects.

Study design: This was a cross-sectional observational case-control study.

Methods: Thirty eyes of 15 psoriasis patients were included in the study and compared with 30 eyes of 15 control subjects. Corneal biomechanical properties were calculated by ORA. Central corneal thickness (CCT) was measured by anterior-segment optical coherence tomography. The main outcome measures were corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and Goldmann-correlated IOP (IOPg). For dry-eye evaluation, Schirmer's test was used.

Results: Mean CH in the psoriasis group was 10.20±1.55 mmHg and in the control group 10.66±1.36 mmHg (p=0.215). Mean CRF in the psoriasis group was 9.76±1.60 mmHg and in the control group 10.97±1.42 mmHg (p=0.003). Mean IOPcc in the psoriasis group was 14.84±3.43 mmHg and in the control group 16.67±3.17 mmHg (p=0.035). Mean IOPg in the psoriasis group was 13.92±3.35 mmHg and in the control group 16.62±3.10 mmHg (p=0.002). Mean CCT in the psoriasis group was 543.90±37.27 µm and in the control group 551.23±28.63 µm (p=0.392). Schirmer's test results in the psoriasis group were 11.4±1.57 mm/5 min and in the control group 17.5±1.52 mm/5 min (p<0.001).

Conclusion: Psoriasis affects corneal biomechanical properties with statistically significantly lower corneal biomechanics than normal. CH correlates negatively with disease activity. These corneal biomechanical changes should be considered when determining IOP values and during corneal evaluation for keratoconus-suspected patients.

Keywords: corneal hysteresis; corneal resistance factor; corneal-compensated intraocular pressure; ocular response analyzer; psoriasis.