Bulbar conjunctival microvascular responses in dry eye

Area of Science:

• Ophthalmology
• Neuroscience
• Vascular Biology

Background:

• Dry eye (DE) may involve somatosensory dysfunction.
• Conjunctival microvascular responses can indicate neural pathway function.
• Assessing microvascular alterations may offer insights into DE pathophysiology.

Purpose of the Study:

• To investigate correlations between bulbar conjunctival microvascular changes and dry eye (DE) features.
• To evaluate conjunctival microvascular responses to air puff stimulation in DE patients.

Main Methods:

• Fifty-six DE patients underwent temporal bulbar conjunctiva imaging before and after corneal air puff stimulation.
• Functional slit lamp biomicroscopy (FSLB) was used to measure blood flow velocities and create noninvasive microvascular perfusion maps (nMPMs).
• DE symptoms, ocular pain, and signs were assessed; correlations with microvascular parameters were analyzed.

Main Results:

• Bulbar conjunctival blood flow velocity significantly increased post-stimulation (P < 0.001).
• Baseline blood flow velocity positively correlated with Schirmer scores (r = 0.40, P = 0.002).
• Reduced change in blood flow velocity was associated with higher wind hyperalgesia (r = -0.268, P = 0.046).

Conclusions:

• Conjunctival blood flow velocity, unlike vessel diameter or complexity, increases following wind stimuli.
• Baseline conjunctival blood flow velocity is linked to tear production (Schirmer scores).
• The change in conjunctival blood flow velocity after stimulation is inversely related to wind-induced pain sensitivity in dry eye patients.