Abstract: Cataract surgery is one of the most commonly performed surgeries among the elderly today. The volume of cataract surgeries has dramatically increased in the past few decades due to technological advancements leading to decreased morbidity, better overall outcomes, and increased expectation for correction of refractive error and spectacle independence after cataract surgery. The number of cataract surgeries is expected to continue to rise with the increase of the elderly population. Thus, accurate predictions of intraocular lens (IOL) power and the ability to correct for any postoperative refractive errors are critical. Despite the improved ability of cataract surgeons to accurately calculate IOL power, postoperative refractive errors still do occur due to various reasons such as imperfect preoperative measurements, toric-lens misalignment, and existing or surgically-induced astigmatism. The aim of this article is to review the various surgical options, including intraocular and corneal refractive surgical approaches, to correct post-operative refractive errors after cataract surgery.
Background: To measure the anterior and posterior segment structural features of acute primary angle-closure (APAC) eyes.
Methods: A total of 36 subjects with unilateral APAC were recruited in this study. The ocular biometric characteristics were measured by anterior segment optical coherence tomography (AS-OCT) and swept source optical coherence tomography (SS-OCT), respectively at baseline, 2 weeks, and 1 month after surgical intervention.
Results: At baseline, when compared with the fellow eyes, APAC-affected eyes showed significantly greater corneal thickness (P=0.004), shallower anterior chamber depth (ACD) (P<0.001), smaller anterior chamber area (ACA) (P=0.013), angle opening distance at 750 μm from the scleral spur (AOD750) (P=0.002), trabecular–iris space area at 750 μm from the scleral spur (TISA750) (P=0.033), angle recess area (ARA) (P=0.014), and iris area (IARE) (P=0.003), less iris curvature (ICURVE) (P=0.003), and larger lens vault (LV) (P=0.030). After intervention, the corneal thickness was significantly decreased at 1 month (P<0.001), while ACD, ACA, and AOD750 were significantly increased at 2 weeks and 1 month (all P<0.017). Changes in ACD were correlated with decreasing LV (P<0.05). The posterior segment parameters did not change over the 4-week period.
Conclusions: When compared with the fellow eyes, APAC-affected eyes had greater corneal thickness, shallower anterior chamber, narrower angle, less ICURVE, and larger LV. After intervention, the corneal thickness was decreased, while the shallower anterior chamber was relieved to some extent.
Background: To investigate the microstructural features of parapapillary gamma zone and beta zone and their relationship with three-dimensional optic disc shape in non-myopic eyes.
Methods: This cross-sectional study included 62 non-myopic eyes with parapapillary gamma or beta zone and 70 control eyes. On the spectral domain optical coherent tomography (SD-OCT) images, we measured the area of gamma zone and beta zone, the length of border tissue, and related disc parameters. The disc ovality index, disc rotation degrees around three axes, Bruch’s membrane opening (BMO) ovality ratio were calculated based on the SD-OCT images.
Results: The parapapillary gamma zone composed by externally oblique border tissue was found in inferior, nasal and temporal quadrants of the non-myopic eyes. The presence of gamma zone in non-myopic eyes was correlated with smaller disc ovality index, larger rotation degree around vertical and horizontal axes, and larger BMO ovality ratio (P<0.001). Compared with the non-temporal gamma zone group, eyes with temporal gamma zone had a longer axial length and rotated more around vertical axes (P<0.001). Multivariate analysis showed that the area of gamma zone was correlated with the disc ovality index (P<0.001). The presence and area of beta zone was correlated with age (P<0.01).
Conclusions: In non-myopic eyes, the parapapillary gamma zone composed by external oblique border tissue was significantly associated with the disc ovality and disc rotations around vertical and horizontal axes. From a biomechanical perspective, parapapillary gamma zone may contribute to the optic disc stability in association with the structure of BMO.
