Biometric Indicators of Anterior Segment Parameters Before and After Laser Peripheral Iridotomy by Swept-Source Optical Coherent Tomography

Background Primary angle closure glaucoma (PACG) is the most common type of glaucoma in China. Laser peripheral iridotomy (LPI) is the primary choice to treat PAC. We aim to evaluate the changes and to find the biometric indicators of anterior segment parameters before and after laser peripheral iridotomy (LPI) in primary angle closure (PAC) eyes using swept-source optical coherent tomography (OCT). Methods LPI was performed in 52 PAC eyes of 28 participants. The change of intraocular pressure and anterior segment parameters, including angle opening distance (AOD500), AOD500 area, trabecular iris space area (TISA500), TISA500 volume, trabecular iris angle (TIA500), iridotrabecular contact (ITC) index, ITC area, anterior chamber volume (ACV), anterior chamber depth (ACD), lens vault (LV) and lens thickness (LT) before and 1 week after LPI were measured by Tomey CASIA2 anterior segment OCT. We also estimate and analyze potential contributing factors possibly affecting the change of anterior chamber angle parameters. Results No post-laser complications were found. The LV and LT did not change significantly 1 week after LPI. AOD500, AOD500 area, TISA500, TISA500 volume, TIA500, ACV and ACD increased significantly after LPI. There was significant decrease in ITC index and ITC area. LT was positively correlated to the change of ITC index (r=0.411, p=0.002) and ITC area (r=0.384, p=0.005). ACD was negatively correlated to the change of ITC index (r=0.292, p=0.036). Conclusions The anterior segment architecture significantly changed after LPI in PAC spectrum eyes. Crystalline lens measurements remained unchanged before and after LPI. AS-OCT can be used to follow anterior chamber parameter changes in PAC spectrum eyes. Pre-treatment LT and ACD affect the therapeutic effect of LPI.

Optical coherent tomography in the diagnosis of inflammatory and ischemic optical neuropathies (clinical cases)

Optic neuropathy is a group of diseases of the optic nerve. Using diagnostic techniques such as ophthalmoscopy and perimetry diagnosis are insufficient, as the found abnormalities are not specific for either inflammation or ischemia. Establishing the predominant factor in the pathogenesis of neuropathy is crucial in determining the method of treatment. The aim of the study: to investigate the features of optic nerve damage using optical coherent tomography (OCT) in optic neuropathy in the acute period. Materials and methods: two patients with visual impairment were examined. Result. Patient G. had concomitant rheumatoid arthritis with unregulated Methotrexate therapy. OCT revealed edema of the nerve fibre layer convinced of the predominance of inflammatory neuropathy (atypical neuritis). Pulse therapy with corticosteroids was prescribed, which gave a positive functional effect. A patient O. with pneumonia on the background of Covid-19 with a history of OST showed a decrease in the thickness of the layer of nerve fibres in the lower segment, and in the angio mode – drusen of the optic disc. Conclusions. Thus, the use of OCT for the diagnosis of optic neuropathies in the acute period showed that under conditions of inflammatory lesions is more characteristic of edema and an increase in the thickness of the layer of nerve fibres. In ischemic neuropathy, on the contrary, a decrease in the thickness of nerve fibres is more characteristic, which correlates in location with the localization of scotoma in the field of view. Therefore, the use of OCT of the optic nerve will help in understanding the pathogenesis of forms of optic neuropathy. This will help in the choice of treatment tactics

OCT on Anterior Segment Anomalies of the Eye in a Polish Paediatric Cohort: Diagnostic and Therapeutic Challenges

Purpose. To present applications of anterior segment optical coherent tomography (AS OCT) for anomalies of the eye in a Polish paediatric cohort. Materials and Methods. Seventy-four eyes of infants and older children were examined. The majority of them underwent general anaesthesia to allow OCT to be performed in the operating room, but a few were examined in a routine way. We focused on corneal, anterior chamber, iris, and lens disorders. Measurements included corneal morphology, anatomy of the anterior chamber, and general involvement of surrounding tissues in pathologic lesions. Results. We divided the paediatric patients into several groups by considering the type of disease and involvement of particular tissues. The groups were selected based on OCT usefulness in describing their ocular disorders. Conclusion. The collected anterior segment disorders showed huge usefulness for paediatric diagnosis and treatment planning.