Evaluation of macular segmentation and retinal vessel diameters in central retinal artery occlusions

SUMMARY Evaluation of Macular Segmentation and Retinal Vessel Diameters in Central Retinal Artery Occlusions Dr. Tahsin AKÇAOĞLU Central retinal artery occlusion is a pathology that begins suddenly and causes permanent vision loss, usually affecting one side, and requires urgent treatment. Central retinal artery occlusion is an important cause of morbidity. Systemic diseases that cause obstruction usually affect all body vessels. For this reason, failure to diagnose the disease and failure to conduct research on the disease may lead to life-threatening situations for the patient. Our study aims to show the changes starting from the moment of diagnosis in the retinal layers in the macular region of the disease, retinal vessel diameters, subfoveal and peripapillary choroidal thicknesses during the follow-up of patients diagnosed with unilateral central retinal artery occlusion. Patients diagnosed with central retinal artery occlusion, who came to Pamukkale University Hospitals Ophthalmology Polyclinic, applied to our hospital's emergency department, were consulted by us, and were subsequently followed up and treated by us, were included in this study. Demographic data and disease-related data (age, gender, systemic diseases, symptoms, onset time, which eye is affected, whether they have been traumatized) were obtained from the patients medical file records. Best-corrected visual acuity, intraocular pressures, anterior and posterior segment examination findings, fundus photographs, and OCT examination results were included in the initial examination of all patients recorded in the hospital information system, and the examination and measurement records made during the visits covering the study period were evaluated retrospectively. The visual acuity of the patients was first measured with the Snellen chart and then converted to logMAR for statistical analysis. 70 eyes of 35 patients were included in our study, and the other eyes that were not affected by the disease were accepted as the control group. The mean age of the patients was 70.03±12.48 years and the median was 71 years. The mean eye pressure of the patients was 12.86±3.32 mmHg and the median was 12 mmHg. There was no significant age difference between male and female genders (p>0.05). 40% of the patients had DM, 74.3% had HT and 42.9% had cardiovascular disease. When the visual acuity of the patients was evaluated, the majority of them were at the level of hand movements. There were no light-negative patients at the beginning and end of the study. It was observed that the retinal artery diameters of the patients became thinner during follow-up. While the initial retinal artery diameters were 77.91±11.77 µm, the retinal artery diameters were found to be 70.74±15.12 µm at the last follow-up (p<0.05). A thinning was also detected in retinal vein diameters. While the initial retinal vein diameter was 130.94±22.54 µm, it was 118.57±20.61 µm in the last control measurements and the thinning was found to be significant (p<0.05). Initial retinal artery diameters, final control retinal artery diameters and final control retinal vein diameters did not differ significantly depending on whether the patients received hyperbaric treatment or not (p>0.05). The central macular thickness of the patients showed thinning in both groups, regardless of treatment. While the central macular thickness was found to be 292.74±92.03 µm at baseline measurements, it was measured as 169.97±39.24 µm at the last visit (p<0.05). Macular segmentation was performed with Spectral-domain Optical Coherence Tomography. Significant atrophy findings and thinning were detected in the inner layers (RNFL, ganglion cell, IPL, INL) at the last follow-up, and although there was partial thinning in the other layers, it was proportionally less than the inner retina layers. In the study, it was found that the layer with the greatest thickness increase at first and then atrophy the most was the RNFL. The initial thickness was 40.09±26.86 µm and the final thickness measurement was 12.51±4.99 µm and a significant thinning was detected (p<0.005). The least affected layer was the photoreceptor cell layer. The initial measurement was 24.60±7.30 µm, and in the final measurements it was found to be 22.89±5.98 µm, and no significant difference was found (p>0.05). Significant thinning in subfoveal choroidal thickness (SFCT) was detected. While the initial SFCT was 206.40±34.91 µm, it was found to be 178.86±28.28 µm at the last follow-up (p=0.009). Contrary to other parameters, an increase in peripapillary choroidal thickness was detected. In measurements taken from four different quadrants, the thickest choroidal thickness was found to be in the nasal quadrant and the thinnest thickness was found to be in the inferior quadrant.While the first nasal measurement of peripapillary choroidal thickness measured was 263.11±41.13 µm, the last measurement was 278.37±41.15 µm and the increase in thickness was considered significant (p<0.05). In the measurements taken from the inferior quadrant, the beginning was 219.54±37.59 µm and the last measurement was 246.34±48.24 µm and the increase in thickness was significant (p<0.005). As a result, central retinal artery occlusion is a rare but important disease group due to its consequences. The thinning of the inner retinal layers, thinning of the retinal vessel diameters and thickening of the peripapillary choroidal thickness due to central retinal artery occlusion have been revealed. The continuation of the blockage that causes central retinal artery occlusion is the main reason that causes changes on the retina. Cases in which the occlusion was not opened were included in the study. Similar morphological changes were detected in the groups that received and did not receive hyperbaric treatment. Keywords: Central Retinal Artery Occlusion, Retinal Artery Occlusion, Macular Segmentation, Optical Coherence Tomography