Change in Subfoveal Choroidal Thickness following Cataract Surgery Imaged with Enhanced Depth Imaging Optical Coherence Tomography.

BACKGROUND: Due to its invasive nature, cataract surgery can lead to inflammatory processes in the posterior segment, which can result in prolonged recovery times, reduced functional outcomes, and late-onset complications. The aim of the current study was to identify wherever phacoemulsification parameters play a role in choroidal thickness change following cataract surgery. METHODS: This prospective single-center study enrolled 31 patients (31 eyes) scheduled to undergo routine cataract surgery. Patients with previous ocular surgeries, pathologies or general disorders affecting vision were excluded. Patients were examined preoperatively, as well as 1, 4, and 12 weeks after surgery. Corrected distance visual acuity (CDVA), intraocular pressure (IOP) as well as cumulative dissipated energy (CDE), ultrasound time (UT), and fluids used during surgery were recorded. Subfoveal choroidal thickness was measured manually by two masked independent experts using enhanced depth imaging (EDI) optical coherence tomography (OCT). Furthermore, cataract density was automatically calculated using a custom MATLAB script and an anterior segment OCT. RESULTS: Subfoveal choroidal thickness increased significantly (p < 0.001, Student's paired sample t-test) and continuously during the 12-week-long follow-up period. Both the nuclear lens density and the improvement in CDVA correlated significantly with this increase (r = 0.413, p = 0.021 and r = 0.421, p = 0.018, respectively). Neither the CDE (r = 0.334, p = 0.071), the UT (r = 0.102, p = 0.629), the amount of fluid used (r = 0.237, p = 0.27) nor the decrease in IOP (r = - 0.197, p = 0.288) showed any significant correlation with the choroidal swelling. CONCLUSION: Cataract surgery leads to an increase in subfoveal choroidal thickness. While no statistically significant correlation to the phacoemulsification parameters could be established, this might be because of a selection bias due to the technological constraints of the OCT. Nevertheless, the choroid might play a central role in early- and late-onset complications.

Injection time related to intraocular pressure using a CO2 driven preloaded injector: An experimental laboratory study.

PURPOSE: Experimental study to measure the intraocular lens (IOL) injection time and injection speed at different intraocular pressure (IOP) settings when using the AutonoMe® injector. METHODS: In this experimental study, following phacoemulsification in porcine cadaver eyes, a trocar was inserted at pars plana with a connected infusion and IOPs of 20, 50 and 80 mmHg were generated by altering the infusion height. Twelve CO2 gas-driven injectors were used to implant an IOL via a corneal incision of 2.2 mm. For each IOP setting, the duration of the IOL injection and the injection speed was measured by analyzing a video recording of the procedure. RESULTS: The mean ±SD injection time (seconds) was 4.47±0.50 at 20 mmHg, 4.98±0.55 at 50 mmHg and 5.47±0.20 at 80 mmHg. The mean ±SD injection speed (millimeters per seconds) was 1.36±0.15 at 20 mmHg, 1.22±0.14 at 50 mmHg and 1.10±0.04 at 80 mmHg. There was a significant (p<0.05) difference between the 20 and 80 mmHg groups in mean injection duration and injection speed. CONCLUSION: The CO2 gas driven injector allows a safe IOL injection even at elevated IOP. Although the implantation time is slightly extended at higher IOPs, this does not seem to be clinically relevant. No IOL damage was observed at these pressure settings.

The impact of glistenings on the optical quality of a hydrophobic acrylic intraocular lens.

PURPOSE: To study the effect of glistenings on the optical quality of a hydrophobic acrylic intraocular lens (IOL). SETTING: David J. Apple Laboratory, Heidelberg, Germany. DESIGN: An in vitro laboratory study. METHODS: An accelerated aging protocol was used to induce glistenings (microvacuoles) in 38 hydrophobic acrylic IOLs. The IOLs were warmed to 45°C and then cooled to 37°C. Image analysis of light-microcopy photographs determined the number and size of microvacuoles (MV). A classification was applied based on the glistening number per mm2: grade 0 (none), grade 1 (1-100), grade 2 (101-200), grade 3 (201-500) and grade 4 (more than 500). An optical bench was used to measure each IOL's modulation transfer function (MTF) and Strehl ratio to evaluate the impact of glistenings on image quality. RESULTS: Glistenings were observed in all IOLs. The mean glistening numbers ± SD (MV/mm2) in grades 1 through 4 were 74 ± 12.7, 142 ± 22.2, 297 ± 76.2, and 1509 ± 311.9, respectively. The mean glistening sizes in grades 1 through 4 were 13.28 ± 3.85 µm, 15.88 ± 2.08 µm, 16.85 ± 3.23 µm, and 15.27 ± 2.25 µm, respectively. Statistical analysis showed that grades 1 through 3 did not change the optical quality; however, in grade 4, the MTF and the Strehl ratio were significantly affected. CONCLUSION: A limited number of glistenings (<500 MV/mm2) had no effect on the image quality. Although statistically significant deteriorations in the MTF and the Strehl ratio were observed in grade 4, the effects found were small and are unlikely to affect the visual quality.