Novel Method Measuring Conjunctival Microvascular Blood Flow Velocity by Zoom-lens, Ultra-high-speed Camera Attached Slit-lamp Biomicroscope

Purpose@#To introduce an intuitive method for measuring conjunctival microvascular blood flow velocity by imaging bulbar conjunctival microvessels using a slit-lamp biomicroscope equipped with a zoom lens and an ultra-high-speed camera. @*Methods@#After obtaining consent from 10 patients (1 male, 9 females) who visited Yeouido St. Mary’s Hospital from August 21, 2020, to June 12, 2021, the patients were examined under a slit lamp microscope equipped with an ultra-high-speed camera and zoom lens. The blood flow in the conjunctival microvessels was photographed. The captured images were analyzed with ImageJ software to measure the blood flow velocity in the conjunctival microvessels, and we investigated whether the blood flow velocity correlated with the vessel diameter and age. @*Results@#The median age of the subjects was 49.0 years. The mean conjunctival blood flow velocity in 53 microvessels was 0.786 ± 0.468 mm/s. The median conjunctival microvascular diameter was 7.06 μm (interquartile range 5.84 to 9.23 μm). The conjunctival microvascular diameter and blood flow velocity were not significantly correlated (Spearman’s p = 0.177), and the subjects’ age and conjunctival microvascular blood flow velocity were also not correlated (Spearman’s p = 0.669). @*Conclusions@#In this study, the blood flow velocity in the bulbar conjunctival microvessels could be measured easily by means of image analysis using a slit-lamp microscope equipped with an ultra-high-speed camera with a zoom lens.

Age-related Changes in Anterior, Posterior Corneal Astigmatism in a Korean Population

PURPOSE: To evaluate age-related changes in anterior and posterior corneal astigmatism in Koreans. METHODS: The anterior and posterior corneal astigmatisms of 160 subjects with age ranging from 11 to 92 years, none of whom experienced any complications, were measured with a rotating Scheimpflug camera (Pentacam®). Using this data, the changing proportions of with-the-rule to against-the-rule and changing tendency of anterior and posterior corneal astigmatisms with age were evaluated using polar value analysis according to the Naeser method. RESULTS: For the anterior cornea, the proportion of with-the-rule astigmatisms decreased with age (p < 0.0001). On the other hand, for the posterior cornea, the proportion of against-the-rule astigmatisms decreased with age (p = 0.012). In the polar value analysis, there was a trend toward against-the-rule astigmatism associated with increasing age for the anterior cornea (p < 0.0001) and toward with-the-rule astigmatism for the posterior cornea (p < 0.0001). CONCLUSIONS: In previous studies, the anterior corneal surface shifted from with-the-rule to against-the-rule astigmatism with increasing age, whereas the posterior corneal surface remained as against-the-rule astigmatism in most cases. But, our results showed that the proportion of against-the-rule astigmatisms of the posterior cornea decreased with age. Thus, evaluation of posterior corneal astigmatisms should be performed before cataract surgery in old patients, especially when using a multifocal or toric intraocular lens.

Comparison of the Clinical Outcomes of Two Types of Toric Intraocular Lens

PURPOSE: In this study evaluated clinical outcomes and higher-order aberrations in patients with implanted Tecnis ZCT toric intraocular lens (IOL) (Abbott Medical Optics Inc., Santa Ana, CA, USA) and the Zeiss AT TORBI toric IOL (Carl Zeiss Meditec AG, Jena, Germany) in eyes with low to moderate corneal astigmatism. METHODS: We conducted a retrospective study of 32 consecutive eyes of 26 patients with a visually significant cataract and moderate corneal astigmatism (higher than 1.25 diopter [D] and lower than 4.5 D) undergoing cataract surgery with implantation of the aspheric Tecnis ZCT toric IOL (Abbott Medical Optics Inc.) and the Zeiss AT TORBI toric IOL (Carl Zeiss Meditec AG). Phacoemulsification was performed by the same experienced surgeon using 2.2 mm temporal incision. Visual, refractive and aberrometric changes were evaluated during a 3-month follow-up. Power vector analysis of Cartesian astigmatism (J0) and oblique astigmatism (J45) was performed. RESULTS: At the 3-month follow-up, corrected distance visual acuity (CDVA) and residual astigmatism showed no statistically significant differences between groups (p = 0.203 and p = 0.364, respectively). Pre- and postoperative J0 were 0.71 +/- 0.84 and 0.05 +/- 0.39 in the Tecnis Toric group and, 0.88 +/- 1.27 and -0.02 +/- 0.16 in the AT TORBI group, respectively, which showed statistically significant differences (p = 0.029 and p = 0.032, respectively). Pre- and post-operative differences of J0 and J45 were not statistically significant (p = 0.234 and p = 0.603, respectively). No eye had IOL rotation > or =10degrees. Ocular aberrometry values were statistically significantly differenct between the groups, except for spherical aberration, which was higher in the AT TORBI group (p = 0.0047). CONCLUSIONS: Both IOLs showed good postoperative uncorrected distance visual acuity, CDVA and refractive results in this study. Rotational stability was excellent for both IOLs until the 3-month follow-up.