A new study has identified key relationships between subretinal fluid (SRF) characteristics and outer retinal layer reflectivity in patients with central serous chorioretinopathy (CSCR), suggesting that optical coherence tomography (OCT)-derived reflectivity metrics may provide valuable insight into disease progression.

Published in Investigative Ophthalmology & Visual Science, the retrospective cross-sectional study by Ekin Ece Oskan, MD, and colleagues of the Haseki Training and Research Hospital in Istanbul, Turkey, analyzed 33 eyes with CSCR and 33 matched controls. Reflectivities of the retinal pigment epithelium (RPE), external limiting membrane (ELM), and ellipsoid zone (EZ) were measured at 3 anatomic locations using OCT.

Findings

Average reflectivity values for the RPE, ELM, and EZ were significantly lower in CSCR eyes than in controls (P<.001). In the subgroup with pigment epithelium detachment (PED), EZ reflectivity values were further reduced compared with the non-PED group (P=.012 for nasal EZ; P=.013 for average EZ).

The researchers also found negative correlations between SRF dimensions and outer retinal reflectivity. Specifically:

• SRF base width correlated negatively with average EZ (P=.018) and average ELM (P=.021).

• SRF area correlated negatively with both average EZ (P=0.049) and average ELM (P=.025).

• RPE central reflectivity showed a negative correlation with SRF height (P=.016).

Patients with chronic CSCR (eyes with SRF lasting over 3 to 6 months) demonstrated lower EZ and ELM reflectivity values than those with acute disease after age adjustment (average EZ, P=.017; average ELM, P=.010). Conversely, relative reflectivity ratios were higher in acute cases, while the ratio of EZ/ELM to RPE reflectivity was lower in chronic cases. PED was present in 15.2% of patients, and this subgroup exhibited marked reductions in EZ reflectivity. The authors suggested “that PED may exacerbate the adverse effects of SRF on retinal structures” and that “identifying patients with PED and monitoring their reflectivity changes could thus be an essential step in preventing the progression to chronic CSCR.”

Longer symptom duration correlated with lower reflectivity values, suggesting that prolonged exposure to SRF causes cumulative photoreceptor stress, metabolic disruption, increased retinal disorganization and longer recovery times. “Even after the SRF is managed,” the authors wrote, “the reflectivity values in affected regions remain significantly lower than those in healthy controls. The implication here is that the damage caused by SRF is not merely transient but can lead to prolonged, possibly irreversible alterations in retinal structure.”

Study Population and Imaging

Participants were a mean age of 45.5±11.5 years, and 63.6% were male. Among CSCR eyes, 60.6% were acute and 39.4% were chronic. OCT scans were obtained using the AngioVue Avanti RTVue-XR system, and reflectivity analyses were performed using ImageJ software. Only images with a signal quality index of at least 7/10 were included. Interobserver agreement for reflectivity measurements was excellent (intraclass correlation coefficients, 0.91-0.97).

Limitations

The authors acknowledged limitations including the cross-sectional and retrospective design, small sample size, and restricted spatial sampling at three retinal points. Although age adjustment was performed, subtle measurement variability due to imaging angle and signal strength could not be completely excluded. All participants were Caucasian, so applicability to other populations may be limited.

Clinical Implications

Reflectivity measurements should be incorporated into routine clinical practice to track disease activity and treatment response, guide timing and intensity of interventions, and identify patients who need early or aggressive treatment to prevent photoreceptor loss, the authors wrote. They added that the correlation between decreased EZ reflectivity and larger SRF accumulation suggests that patients with significant EZ damage may benefit from earlier intervention. Treatments such as mineralocorticoid receptor antagonists or photodynamic therapy should target SRF reduction to preserve retinal integrity. Further, they cited additional research which demonstrated that the structural integrity of the EZ prior to photodynamic therapy could predict visual outcomes after treatment.

They concluded, “The preservation of the outer retinal layers, particularly the EZ, is crucial for optimal visual outcomes, and timely intervention to reduce SRF is essential to prevent irreversible damage. The associations between reduced reflectivity and increased SRF dimensions underscore the need for regular, quantitative OCT assessments to guide personalized treatment approaches.” RP