Optic Disc Changes After Acute Primary Angle Closure

Abstract

Abstract: : Purpose: To evaluate the changes in optic disc in the first 16 weeks after an episode of acute primary angle closure (APAC) using stereoscopic optic disc photography and digital optic disc planimetry. Methods: This was a prospective, observational study of 47 Asian patients presenting with APAC, who were successfully treated with laser peripheral iridotomy. Stereoscopic optic disc photographs were taken at week 2 and week 16 during the follow–up period after APAC. The images were then analyzed with a computer–assisted planimetric measurement program, corrected for ocular magnification. The overall and quadrantic areas of the optic disc, cup–disc ratio (CDR) and neuroretinal rim (NRR) were measured by 2 independent graders and the mean of the readings were used to calculate the changes in optic disc parameters during the period. Results: The mean age of the study population was 67.6 ± 11.2 years. (range, 40–104 years). The majority of the subjects were female (66%) and Chinese (90%). From week 2 to week 16, the mean CDR increased from 0.56 ± 0.05 to 0.59 ± 0.03 (p<0.001) and the mean surface area of NRR decreased from 1.74 ± 0.31 mm² to 1.59 ± 0.27 mm² (p<0.001). There was no significant change in the mean optic disc area (p=0.19). Conclusions: This study demonstrated significant changes in optic disc parameters, namely CDR and NRR, from week 2 to week 16 after an episode of APAC.

Keywords: optic disc • imaging/image analysis: clinical • clinical (human) or epidemiologic studies: natural history