Prior to Macular Hole, Choroid Thickness Decreases

Vessel density measurements of the retinal capillary plexuses show a decrease in choroidal thickness that may precede macular hole formation, according to a study published in Photodiagnosis and Photodynamic Therapy. The research relied on optical coherence tomography angiography (OCT-A) imaging.  

Researchers conducted a retrospective case series that included 20 patients with unilateral idiopathic macular hole (IMH) (3 men, 17 women; mean age, 63.80 years; preoperative acuity in the eye with IMH, 1.65 logarithm of the minimum angle of resolution [logMAR]) and 20 age- and sex-matched patients to serve as a control group (3 men, 17 women; mean age 62.8 years; 0.08 logMAR). All participants were imaged with OCT-A between 2019 and 2021.

Among the IMH group, significant differences between the IMH eye and fellow eye were observed for vascular densities in the temporal (mean, 50.71 vs 59.05 µm; P <.001), nasal (mean, 48.73 vs 58.57 µm; P <.001), superior (mean, 53.47 vs 58.44 µm; P =.032), and inferior (mean, 52.88 vs 57.75 µm; P =.040) regions and retinal thickness in the temporal (mean, 376.00 vs 302.20 µm; P <.001), superior (mean, 381.80 vs 313.60 µm; P <.001), nasal (mean, 401.15 vs 314.25 µm; P <.001), and inferior (mean, 385.55 vs 309.45 µm; P <.001) regions. 

In the macular fovea, the IMH eyes had significantly lower fovea blood flow area (mean, 1.38 vs 1.77 mm²; P <.001), retinal thickness (mean, 381.45 vs 234.50 µm; P <.001), subfoveal choroidal thickness (mean, 203.65 vs 256.25 µm;  P =.002), superficial capillary plexuses (mean, 20.84 vs 25.56%; P =.004), and deep capillary plexuses (mean, 25.46 vs 20.44%; P =.017). The fellow eye was associated with lower fovea blood flow area (P =.012) and subfoveal choroidal thickness (P =.018) compared with healthy eyes.

Among the IMH eyes, significant correlations were observed between vascular density of the superficial capillary plexuses and retinal thickness in the fovea (r, 0.519; P =.019) and vascular density of the deep capillary plexuses and retinal thickness in the inferior (r, -0.788; P <.001), para-fovea (r, -787; P <.001), superior (r, -0.757; P <.001), temporal (r, -0.680; P <.001), nasal (r, -0.642; P =.002), and fovea (r, -0.608; P =.004) regions.

The major limitation of this study was the small sample size.

“The morphology of retina and choroid in idiopathic macular hole is different from that in fellow eye. The thickness of choroid in the fovea area of the unaffected eye also showed a decreasing trend. Taken together, the mechanism of macular hole may be further understood, that is, the decrease of choroid thickness may occur before the macular hole formation,” the researchers explain. “It was verified again that the choroidal blood flow area in macular fovea of IMH patients was significantly lower than that in fellow eyes and healthy eyes.”