Abstract
Background
To evaluate choroidal thickness, ganglion cell complex and photoreceptor outer segment length in patients with breast cancer undergoing tamoxifen therapy using spectral domain optical coherence tomography (SD-OCT) and to compare the results to normal eyes.
Methods
Fourty four patients with breast cancer undergoing tamoxifen therapy and fourty one healthy controls were included in this prospective, comparative study. All participants underwent a complete ophthalmologic evaluation and SD-OCT. Subfoveal, nasal (nasal distance to fovea 500 μm, 1000 μm, 1500 μm) and temporal (temporal distance to fovea 500 μm, 1000 μm, 1500 μm) choroidal thickness measurements were performed using enhanced depth imaging mode of SD-OCT. Using an Early Treatment Diagnostic Retinopathy Study (ETDRS) circle at the macular level, the automated retinal segmentation software was applied to determine thicknesses of the ganglion cell complex (GCC) by adding the macular retinal nerve fiber layer, macular ganglion cell layer, and macular internal plexiform layer parameters. The photoreceptor outer segment (PROS) length was determined by manually as the distance from inner surface of ellipsoid zone to inner surface of retina pigment epithelium after automatic retinal segmentation.
Results
The mean choroidal thickness measurements were statistically greater in tamoxifen group than controls in all quadrants (p<0.001 for all quadrants). Of all tamoxifen users (44 eyes of 44 patients), 33 eyes (75%) had uncomplicated pachychoroid (UCP). Pachychoroid pigment epitheliopathy (PPE) was detected in 5 patients (11.3%) in tamoxifen group. Patients with PPE in one eye had UCP in the fellow eye. Central serous chorioretinopathy findings were observed in one patient. Tamoxifen users had statistically lower GCC thicknesses in all inner rings of ETDRS inlay and only in nasal outer ring (p:0.027, p:0.002, p:0.002, p:0.001 and p:0.030; respectively). No statistically significant difference was found between the groups in terms of mean subfoveal PROS length.
Conclusions
SD-OCT provides valuable information in identifying the structural changes and evaluation of ocular findings in patients receiving tamoxifen therapy. Increasing choroidal thickness, PPE, thinning GCC were detected in tamoxifen users. These OCT findings may be an early indicator of retinal toxicity for patients undergoing tamoxifen therapy in follow-up period.
Comparison of photoreceptor outer segment length in diabetic and idiopathic epiretinal membranes
