Predictive value of the characteristics of intraretinal cystoid spaces on early response to antivascular endothelial growth factor treatment in patients with cystoid diabetic macular edema.

Purpose: To evaluate whether baseline spectral-domain optical coherence tomography characteristics of intraretinal cystoid spaces predict visual outcomes in patients receiving intravitreal antivascular endothelial growth factor injection therapy (bevacizumab 1.25mg/0.05ml) for diabetic cystoid macular edema.

Methods: The relationship between the properties of the cystoid spaces before injection and anatomic and functional results after injection were investigated in patients who received three consecutive intravitreal bevacizumab injections for cystoid macular edema. The best-corrected visual acuity for functional success and central subfield thickness for anatomical success were evaluated. The relationship of the location of the cystoid spaces with the integrity of photoreceptors and inner retinal layers was also evaluated.

Results: In 36 eyes of 36 patients, the mean best-corrected visual acuity significantly improved (p=0.002), and mean central subfield thickness decreased after injections (p=0.003). The improvement in best-corrected visual acuity was limited in eyes with outer nuclear layer cysts (p=0.045). Intracystic reflectivity was higher in eyes that poor best-corrected visual acuity than in eyes with successful visual outcomes (p=0.028). The disrupted ellipsoid zone was present in 13 (59.0%) of 22 eyes with outer nuclear layer cysts, whereas in only 1 of 14 eyes (7.1%) without outer nuclear layer cysts (p=0.009). Disorganization of retinal inner layers was present in 15 of 22 (68.1%) eyes with outer nuclear layer cysts, whereas only 2 of 14 (14.2%) without outer nuclear layer cysts had disorganization of retinal inner layers (p=0.013).

Conclusion: Characteristics of intraretinal cystoid spaces may predict prognosis in patients with diabetic cystoid macular edema, and visual gain may be limited in the eyes with outer nuclear layer cysts.