Abstract:  Objective To report the preliminary results of using long-term image registration of 45° fundus photographs for the diagnosis of preperimetric glaucoma in patients with ocular hypertension. Design Retrespective case series. Participants A total of 330 patients (330 eyes) diagnosed with ocular hypertension at the Ophthalmology Clinic of Beijing Tongren Hospital from January 1, 2015, to December 31, 2023. Method The data of PACS and electronic medical records of patients with ocular hypertension were reviewed. 330 patients with initial diagnosis of ocular hypertension, follow-up for more than six months, and with 45° fundus photography data were included. All patients were first subjected to baseline 45° fundus photography and regularly (every 3-6 months) followed up with fundus photography. We use image registration software developed in collaboration between Beijing Institute of Ophthalmology and Beijing Daheng Imaging Company to perform multiple fundus image registrations, and observe with flickering. The interpretation of all results was completed by the corresponding author. Focus on observing local or overall changes in the optic cup and rim, as well as changes in the position of small blood vessels near the boundary of optic cup. Main Outcome Measures The number of cases with morphological changes in the optic disc or retinal nerve fiber layer during image registration and the number of cases ultimately diagnosed with preperimetric glaucoma. Results Among 330 patients with ocular hypertension, The age at the final follow-up was (34.38±16.25) years (10-81 years). Follow up period was 48.73±40.79 months (6-292 months), with a follow-up frequency of 8.15±7.17 times (2-54 times). There were 140 males (42.4%) and 190 females (57.6%). 126 cases (38.18%, 126/330) were ultimately diagnosed with primary open-angle glaucoma (POAG) or juvenile glaucoma (JOAG) through follow-up. Among them, there were 109 cases (86.5%,109/126) with varying degrees of enlargement of the optic cup in one or both eyes (displacement of small blood vessels within the optic disc or narrowing of the upper and lower disc rim), 19 cases (15.1%, 19/126) with varying degrees of reduction in the optic cup in one or both eyes, 5 cases (4.0%, 5/126) with localized RNLFD in the superior-temporal or inferior-temporal regions in one eye, and 7 cases (5.6%, 7/126) with first-degree relatives diagnosed with POAG or JOAG previously or during the patient's follow-up period. When diagnosing glaucoma, all patients (100%) had normal Humphrey field with 24-SITA FAST program testing. Conclusion In this retrospective case series, about one-third of patients with ocular hypertension were diagnosed with preperimetric glaucoma after long-term follow-up. The early diagnosis of preperimetric glaucoma is a long-term follow-up and dynamic assessment process. Registration and follow-up with 45 ° fundus images is a very useful diagnostic tool. The displacement of small blood vessels within the optic disc is an important diagnostic criterion.  

Key words:  Preperimetric glaucoma/diagnosis, Ocular hypertension, Image registration