Objective To evaluate the accuracy of the biometry using immersion B scan and partial coherence interferometry (Lenstar LS900) for the axial length (AL) of silicone oil-filled eyes respectively. Methods Thirty-five silicone oil-filled eyes (38 patients) were included in the study. All of these eyes underwent silicone oil removal, cataract extraction and intraocular lenses implantation. The AL of all the silicone oil-filled eyes was measured with A/B-scan ultrasound and Lenstar LS900 before operation and with Lenstar LS900 after operation. The measured distance was compared respectively. The method of immersion B-scan guided with respective sonic velocity. AL was the sum of corneal thickness, anterior chamber depth, lens thickness, the apparent length of oil bubble (velocity values 996 m/s), the depth of the water layer beneath the oil bubble. Results Thirty-one eyes were measured with Lenstar LS900 before silicone oil removal, and the mean AL was (24.12±1.70) mm, 7 eyes failed to get the results before the operation; 36 eyes were measured with Lenstar LS900 after silicone oil removal, and the mean AL was (24.45±1.89) mm. All eyes were measured with B-scan before silicone oil removal, and the mean AL was (24.87±2.52) mm. The difference (31 eyes) of AL measurement before silicone oil removal by two methods was (−0.00±0.09) mm; the difference (31 eyes) between pre- and post-surgical AL measurement with Lenstar LS900 was (0.02±0.07) mm; the difference (36 eyes) between pre-surgical AL measured with B-scan and post-surgical AL measured with Lenstar LS900 was (−0.02±0.11) mm. All the differences were not statistically significant (t=−0.205, 1.752, −1.280; P＞0.05). The consistency of the results measured by two methods was well in Bland-Ahamn analysis. Conclusions Measurement results of AL between immersion B-scan guided with respective sonic velocity and Lenstar LS900 are high repeatability on silicone oil-filled eyes. The AL of silicone oil-filled eyes can be measured reliably by immersion B-scan guided with respective sonic velocity.
Objective To observe the clinical and multimodal imaging characteristics of eyes with acute macular neuroretinopathy (AMN) associated with COVID-19. MethodsA retrospective clinical study. From December 18 to 26, 2022, 16 eyes of 8 patients with AMN associated with COVID-19 were included in the study. There were 4 males and 4 females; all cases were bilateral. The age was (31.5±9.6) years old. The time from fever to decreased vision was (3.75±1.04) days. The best corrected visual acuity (BCVA), intraocular pressure, slit lamp microscopy, indirect fundus microscopy, fundus color photography, and optical coherence tomography (OCT) were performed in all patients. Infrared fundus photography (IR), OCT angiography (OCTA) and fluorescein fundus angiography (FFA) were performed in 14, 6 and 4 eyes respectively. The BCVA examination was performed using the international standard visual acuity chart, which was converted into logarithm of the minimum angle of resolution (logMAR) BCVA for statistics. The clinical data, IR, OCT and OCTA imaging features of the patients were retrospectively analyzed. ResultsThe logMAR BCVA of AMN eyes was 4.21±0.74, intraocular pressure was (14.87±1.50) mm Hg (1 mm Hg=0.133 kPa). Fundus color photography showed that multiple gray-white petal-shaped lesions were arranged around the macular fovea in 2 eyes; no obvious abnormality was found in the macular area in 14 eyes. Of the 14 eyes examined by IR, 6 eyes had irregular weak reflective lesions around the macular fovea. OCT showed strong reflex in the outer nuclear layer and outer plexiform layer of all eyes, including 15 eyes with elliptical zone injury. In 6 eyes examined by OCTA, the blood flow density of the superficial and deep capillary plexus (DCP) of retina decreased, and the blood flow density of DCP decreased significantly. The en-face image of DCP showed the wedge-shaped strong reflective lesion area with the tip pointing to the central fovea in 2 eyes. No abnormal fluorescence was observed in FFA. ConclusionsThe characteristic manifestation of AMN associated with COVID-19 is weak reflex focus in IR; OCT shows strong reflection in outer core layer and outer plexiform layer; OCTA showed that retinal DCP blood flow density decreased.