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AIM: To study the structural parameters of the optic nerve head and the retinal nerve fiber layer (RNFL) obtained by using Heidelberg Retina Tomograph-II (HRT-II) and the perimetric indices of Humphrey perimetry in normal and preclinical primary closed-angle glaucoma (PACG) subjects and to observe the effect of prophylactic surgeries on these parameters of the preclinical PACG patients. METHODS: Fifty-seven patients (57 eyes) and 30 healthy subjects (60 eyes) were enrolled in the study and classified into 3 separate groups: 60 healthy eyes for normal control, 41 PACG eyes to undergo preventive peripheral iridectomy with or without laser, 16 PACG eyes untreated with surgery. Of the normal control eyes, 41 PACG eyes treated with surgery before treatment and 6 months after treatment and 16 PACG eyes untreated at the first diagnosis and 6 months later were examined with ophthalmic routine examinations, HRT-II and Humphrey perimetry. Visual acuity, intraocular pressure, anterior chamber angle width and cup area (CA), disk area (DA), rim area (RA), cup volume (CV), rim volume (RV), cup/ disk area ratio (CDAR), linear cup/disk ratio (LCDR), mean cup depth (MCD), maximum cup depth (MaxCD), cup shape measure (CSM), height variation contour (HVC), mean RNFL thickness (MRNFLT), RNFL cross sectional area (RCSA) and mean defect (MD) values were obtained from the result reports. The differences of parameters between normal eyes, 41 treated PACG eyes of pre- and post-treatment and 16 untreated PACG eyes at the first diagnosis and 6 months later were comparatively analyzed with statistic software. RESULTS: Among the normal control group, the treated PACG group before surgery and the untreated PACG group at the first diagnosis, there were no significant differences of visual acuity and intraocular pressure. No statistically significant differences of visual acuity, intraocular pressure and the change of anterior chamber angle width were observed between pre- and post-treatment of the treated PACG group and between at the first diagnosis and 6 months later of the untreated PACG group. The MD value was not different between the normal control group and the pre-treated PACG group, but there was significant differences of CA, RA, CV, CDAR, CSM, HVC, MRNFLT and RCSA in HRT-II between them (P < 0.05). By the comparison between the PACG group of 6 months after treatment [48.61% (27.67%) and the untreated group after 6 months of follow-up [66.18% (21.33%)], the preventive surgeries decreased the increasing rate of MD absolute value (P < 0.05). The increasing rate of CA in treated PACG group was lower than that in untreated group (P < 0.05 , while the decreasing rate of RA in treated PACG group was lower than that in untreated group (P < 0.05). The CDAR value in the PACG group with 6 months of treatment was lower than that in the untreated group after 6 months of follow-up (P < 0.05). The CSM, HVC and MRNFLT values in the untreated group after 6 months of follow-up were less than those in the PACG group with 6 months of treatment (P < 0.05). CONCLUSION: The prophylactic (laser) peripheral iridectomy can delay the progression of preclinical PACG. LA: Chinese
Dr. X.-G. Yang, Shaanxi Ophthalmic Medical Center, Fourth Hospital of Xi'an City, Xi'an 710004 Shaanxi Province, China. yangxinguang62@hotmail.com
6.6.2 Automated (Part of: 6 Clinical examination methods > 6.6 Visual field examination and other visual function tests)
6.9.1.1 Confocal Scanning Laser Ophthalmoscopy (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.1 Laser scanning)