During phacoemulsification, a range of variables can affect eye perfusion, including changes in arterial blood pressure, position of blood vessels, venous return of blood and CO₂ levels. A recent study used OCT-angiography (OCT-A) to investigate possible changes of macular perfusion after uncomplicated cataract surgery and found that perfusion alterations in the macula are due to functional hyperemia.

The study included 55 eyes of 55 patients. Patients underwent OCT-A before cataract surgery and at one week, one month and three months post-op. The researchers noted that significant vascular parameter changes in all eyes plateaued one week after surgery and remained stable up to three months after surgery.

These changes occurred in all retinal layers but not in the choroid or choriocapillaris. They saw the greatest increases of vessels percentage area (22.79%), total vessels length (16.71%), average vessels length (166.71%) and junctions density (29.49%) in the superficial vascular complex. The great change in mean lacunarity (-53.41%) was present in the deep vascular complex.

The researchers concluded that functional hyperemia was causing the macular perfusions post-phaco. “We presume the effect is evoked by increased light intensity stimulation of retina after cataract removal,” they said. “Accordingly, phacoemulsification in elderly population could have an advantageous feature in addition to restoring visual acuity.”