1. Ankara University School of Medicine, Department of Ophthalmology Evaluation of Correlations of Macular Choroidal Thickness and Central Macular Thickness with Ganglion Cell Complex Parameters in Pseudoexfoliation Patients Oya Tekeli1, Zeynep Baş1 1. Ankara University School of Medicine, Department of Ophthalmology The mean CT values were; 321.5 ± 12.8 µm, 381.1 ± 11.7 µm and 417.7 ± 19.6 µm in the PEX, PXG and control group respectively. The mean CT in PEX group was significantly thinner than PXG and control (p=0.0001, p=0.0034). The mean CMT were; 253.3 ± 35.8 µm, 258.5 ± 43.4 µm and 255.1 ± 29.9 µm in the PEX, PXG and control group respectively (p=0.528). In PXG patients, average GCL+IPL thickness and minimum GCL+ IPL thickness showed weak negative correlations with CMT (R= -0.2178, R= -0.1843 respectively), but there was no correlation between GCC parameters and CT measurements (R= -0.1218, R= -0.0861). In PEX group, we detected weak positive correlations of average GCL+IPL thickness and minimum ganglion GCL+IPL thickness with CT (R= +0.2246, R=+0.2071 respectively). There was also a positive correlation between CT and RNFL in PEX group. (R=+0.2566) Purpose To evaluate the macular choroidal thickness (CT) and central macular thickness (CMT) in pseudoexfoliation syndrome (PEX), pseudoexfoliation glaucoma (PXG) and age-matched healthy subjects using spectral-domain optical coherence tomography (OCT) and to investigate the correlations of CT and CMT with ganglion cell complex (GCC). Methods This cross-sectional, prospective study included patients diagnosed with PEX, PXG and healthy volunteers. Clinically evident PEX syndrome was defined as having PEX material deposits on the pupil margin and/or the lens capsule. Patients with retinal or macular disorders, those with marked cataract and those with histories of previous ocular surgeries were excluded. Choroidal thickness measurements were performed using OCT device (V/8.0, Carl Zeiss Meditec Inc., Dublin, California) with an enhanced depth imaging (EDI) mode after pupil dilation. The choroid was measured from the outer portion of the retinal pigment epithelium to the inner surface of the sclera. These measurements were made of the subfovea, 3 mm nasal, 3 mm temporal from the centre of the fovea and average of these measurements are taken into consideration. Table 1 presents the parameters investigated in this study.   Table 1. Parameters recorded are shown The pictures show the scanning imaging obtained from a PXG patient in study. (Figure 1&2) Figure 1&2. En face scan and corresponding optical coherence tomography image showing the choroidal thickness Diagnosis and demographic characteristics Retinal nerve fiber layer thickness (RNFLT) Biomicroscopic examination findings Central macular thickness Intraocular pressure measurements Choroidal thickness Visual field parameters; mean deviation (MD), pattern standard deviation (PSD) Ganglion cell complex Conclusions Pseudoexfoliation syndrome is an age-related disorder characterized by accumulation and deposition of microfibrillar material on multiple ocular and extraocular structures. The presence of pseudoexfoliative material in the choroidal vasculature may interfere with the circulation and lead to ischemia [1]. Recent studies showed that both ocular and choroidal blood flow in patients with PEX has been reduced [2]. In the published literature, several studies presented choroidal thinning in patients with PEX and PXG [3] meanwhile You et al has reported that PEX did not alter CT. [4] In the present study we found that, in PXG group choroid was thicker compared to PEX. In PEX group, choroidal changes may represent an indicator for transformation of PEX to PXG. This may be related to the reversibility of this situation with treatment in early phases. In PEX patients, a positive correlation although poor, exists between the average RNFLT and CT. This suggests that, PEX patients early in their disease courses who begin to lose their RNFL, choroidal thinning may be clinically important. Further studies are needed to better understand the association between choroid and pseudoexfoliation. Results The study included; 41 eyes of 29 patients with PEX, 62 eyes of 45 patients with PXG and 30 eyes of 30 healthy subjects. The RNFLT was found to be significantly thinner in 3 areas in PXG group. (Table 2) There was no significant difference between the groups regarding ganglion cell complex analysis. (Table 3)   Average RNFLT (µm) Superior RNFLT(µm) Nasal RNFLT(µm) Inferior RNFLT(µm) Temporal RNFLT(µm) Control group 91.2±10.5 112.0±16.2 72.4±13.0 114.6±18.8 66.0±12.9 PEXS 88.8±14.0 103.4±23.9 62.2±15.1 116.5±20.2 73.5±25.1 PXG 75.3±20.2 (p=0.001) 93.9±26.9 (p=0.01) 64.8±14.2 (p=0.056) 89.4±37.5 (p=0.0004) 57.2±16.4 (p=0.002) References Table 2. Comparison of RNFL thickness between the pseudoexfoliation patients and control group Sibour, G, Finazzo C, Carenini AB. Monolateral pseudoexfoliatio capsulae: a study of choroidal blood flow. Acta Ophthalmol Scand Suppl, 1997(224): p. 13-4. Mitchell P, Wang JJ, Smith W. Association of pseudoexfoliation syndrome with increased vascular risk. Am J Ophthalmol 1997; 124(5): 685–687. Demircan, S, Yilmaz U, Küçük E. The Effect of Pseudoexfoliation Syndrome on the Retinal Nerve Fiber Layer and Choroid Thickness. Semin Ophthalmol, 2016. You, Q.S., Liang X. Pseudoexfoliation: normative data and associations: the Beijing eye study 2011. Ophthalmology, 2013. 120(8): p. 1551-8.   Average GCL +IPL (µm) Minimum GCL+IPL (µm) Control group 76.4 ± 9.3 61.7 ± 17.4 PEXS 70.7 ± 21.4 60.7 ± 27.9 PXG 70.0 ± 17.7 (p=0.89) 58.3 ± 22.4 (p=0.82) Table 3. Evaluation of ganglion cell complex parameters by groups