|Be careful not to misinterpret subretinal transient hyporeflectivity as subretinal fluid in AMD patients. Photo: Jessica Haynes, OD, James Williamson, OD, and Mohammad Rafieetary, OD. Click image to enlarge.|
Certain findings on spectral domain optical coherence tomography (SD-OCT) could be misinterpreted as exudation in patients with age-related macular degeneration (AMD). Among these is subretinal transient hyporeflectivity (STHR), which may simulate the presence of subretinal fluid and lead to unnecessary or premature treatment. Researchers of a recent study found that although most cases of STHR are quick to disappear on their own, exudative signs may present months later, representing the importance of monitoring these patients.
The study included 1,028 eyes of 514 patients with early, intermediate or late AMD. Of these, 21 eyes of 20 patients initially presented with STHR but no exudative signs on SD-OCT, for a prevalence of around 2%. Two of the eyes had early AMD, one had treatment-naïve nonexudative asymptomatic macular neovascularization and 18 had late AMD including one with geographic atrophy and the other 17 with previously treated neovascular AMD (nAMD).
SD-OCT scans detected 35 areas of STHR across the 20-patient cohort, seven with multiple STHR. The researchers wrote, “In all cases, on SD-OCT, STHR harbored the aspect of a small subretinal hyporeflectivity, delimited internally by a continuous external limiting membrane and externally by the RPE-Bruch’s membrane complex. The ellipsoid zone was intact in 1/35 STHR, while in 34/35 the ellipsoid zone presented varying degrees of disruption. Twenty-nine out of 35 STHR (82.8%) were associated with choroidal hypertransmission in 19/21 eyes.” They noted that for eyes with persistent choroidal hypertransmission underneath the STHR, all the STHR disappeared during the year of follow-up.
Interestingly, at the two-month follow-up, 97.1% of STHR had spontaneously disappeared with no clinical intervention. However, throughout the 12-month follow-up period, exudative signs developed in more than half of the eyes (57.1%), including one with early AMD and 11 with nAMD.
“Among the seven eyes with multiple STHR, 85.7% (six out of seven) developed exudative signs, therefore suggesting that the presence of multiple STHR could represent a higher risk of further exudation,” the researchers wrote. However, further investigation must determine why STHR went away suddenly in nearly all patients within two months, during which time no anti-VEGF treatment was given. Based on this finding, the researchers advise not to treat patients who have STHR immediately with anti-VEGF.
“The corollary of our findings is that STHR could be either an early sign of a low-grade leakage or a nonexudative sign,” the researchers concluded. “A longer follow-up is necessary to demonstrate the exudative or nonexudative nature of this lesion.”
Astroz P, Miere A, Amoroso F, et al. Subretinal transient hyporeflectivity in age-related macular degeneration: a spectral-domain optical coherence tomography study. Retina. December 1, 2021. [Epub ahead of print].