Refractive Changes After Implantation of Reversed Intraocular Lens in Cataract Surgery: A Mathematical Model.

PURPOSE: To develop a mathematical model that can predict the amount of refractive change caused by implantation of an intraocular lens (IOL) in a reversed position during cataract surgery. METHODS: A theoretical mathematical formula based on the Gullstrand eye model was constructed to estimate the refractive change of the eye after implantation of a reversed IOL. The refractive change caused by implantation of the IOL in a reversed position was calculated based on the exchange of the anterior curvature with the posterior curvature of the IOL, and the lengthening of the distance between the IOL and the retina. In case of a three-piece IOL with angulation, the amount of refractive change was calculated based on its angle and the total refractive power of the eye, which is dependent on the focal length of the eye. RESULTS: Calculated refractive change for one-piece IOLs was less than 0.10 diopter (D). For three-piece IOLs, the calculated refractive change makes the eye on average 0.77 D more myopic and can increase with the total refractive power of the patient's eye. The mathematical model was applied to seven previously published cases of reverse IOL implantation. CONCLUSIONS: This calculation demonstrates that with an upside-down IOL, there is a small refractive change in the one-piece IOL, including a toric IOL without angulation, but there can be a large refractive change in the three-piece IOL with angulation, especially using a higher power IOL or with a shorter axial length. [J Refract Surg. 2023;39(5):326-331.].

Establishment of an Acanthamoeba keratitis mouse model confirmed by amoebic DNA amplification.

Acanthamoeba castellanii, the causative agent of Acanthamoeba keratitis (AK), occurs mainly in contact lens users with poor eye hygiene. The findings of many in vitro studies of AK, as well as the testing of therapeutic drugs, need validation in in vivo experiments. BALB/c mice were used in this study to establish in vivo AK model. A. castellanii cell suspensions (equal mixtures of trophozoites and cysts) were loaded onto 2-mm contact lens pieces and inserted into mouse eyes that were scratched using an ophthalmic surgical blade under anesthesia and the eyelids of the mice were sutured. The AK signs were grossly observed and PCR was performed using P-FLA primers to amplify the Acanthamoeba 18S-rRNA gene from mouse ocular tissue. The experimental AK mouse model was characterized by typical hazy blurring and melting of the mouse cornea established on day 1 post-inoculation. AK was induced with at least 0.3 × 105 A. castellanii cells (optimal number, 5 × 104), and the infection persisted for two months. The PCR products amplified from the extracted mouse eye DNA confirmed the development of Acanthamoeba-induced keratitis during the infection periods. In conclusion, the present AK mouse model may serve as an important in vivo model for the development of various therapeutic drugs against AK.

Hypertension as a risk factor for recurrent subretinal hemorrhage in polypoidal choroidal vasculopathy.

OBJECTIVE: To investigate the relationship between hypertension and recurrent subretinal hemorrhage (SRH) in eyes with polypoidal choroidal vasculopathy (PCV). DESIGN: Retrospective, comparative case series. PARTICIPANTS: Thirty-eight eyes of 38 patients with PCV. METHODS: Ocular findings and clinical features were analyzed retrospectively in patients with PCV enrolled from January 2011 to December 2013. The patients were divided into 2 groups according to the presence of recurrent SRH after successful initial treatment (rebleeding vs nonrebleeding) and were subdivided into those with and without hypertension, based on history of hypertension, systolic blood pressure (SBP) >150 mm Hg. The relationship between hypertension and recurrent SRH was analyzed. RESULTS: Thirty-eight patients (38 eyes) were included in this analysis. High SBP or history of hypertension was significantly more frequent in the rebleeding group than in the nonrebleeding group (p = 0.014). Subgroup analysis showed that mean time until recurrent SRH was significantly shorter in the hypertensive group than in the nonhypertensive group (p = 0.025). The cumulative incidence of recurrent SRH at 2 years was 43% in the hypertensive group and 20% in the nonhypertensive group. Cox regression after adjustment for age showed that hypertension was associated with a 3.9-fold greater risk of recurrent SRH (p = 0.039). CONCLUSIONS: Recurrent SRH in patients with PCV was more common in hypertensive subjects. Undiagnosed hypertension should be considered when assessing the prognosis of patients with PCV.

Antifibrotic effect of pirfenidone on human pterygium fibroblasts.

OBJECTIVE: The effects of pirfenidone were investigated on cultured human pterygium fibroblasts (HPFs). METHODS: HPFs were obtained from pterygium surgery and subjected to primary culture. After treatment with 0.5, 1.0 or 1.5 mg/mL pirfenidone, MTT and cell migration assays were performed, and procollagen secretion and TGF-ß expression were measured by Western blotting and immunofluorescence analysis. RESULTS: Pirfenidone had a significant inhibitory effect on HPF proliferation, migration and collagen synthesis. There were no differences between the cells treated with 0.5, 1.0 and 1.5 mg/mL pirfenidone and the controls in the MTT assay. After 48 h of treatment with 1.0 or 1.5 mg/mL pirfenidone, TGF-ß expression was significantly decreased. CONCLUSIONS: These findings demonstrate that pirfenidone inhibits the proliferation, migration and procollagen secretion of HPFs at nontoxic concentrations by decreasing TGF-ß expression. Thus, pirfenidone may be considered as a safe adjuvant for pterygium surgery to prevent recurrence.

The yellow intraocular lens and the natural ageing lens.

PURPOSE OF REVIEW: The purpose of this study is to review and evaluate the advantages and disadvantages of blue light (400-480 nm) filtering intraocular lenses (IOLs) when compared with the ultraviolet (UV)-blocking IOLs. RECENT FINDINGS: Theories that blue light could be related to the pathogenesis of age-related macular degeneration (AMD) have led to the use of yellow tinted IOLs in cataract surgery to filter short wavelength light. In spite of the potential benefits, some concerns have been raised. The potential advantages of the blue light filtering IOLs are that they could better mimic the conditions of phakia and therefore be more protective for the retina in decreasing the incidence of AMD. However, the potential disadvantages are that blue light filtering could negatively affect scotopic vision and circadian rhythms in older patients. SUMMARY: These advantages and disadvantages of blue light filtering IOLs have not been proven clinically and thus many questions remain. Studies have shown that each type of IOL may have its own benefits and the type of IOL should be picked on the basis of patients' specific situations. In cataract surgery, considerations such as preexisting AMD, night vision problems or sleep problems may be considered with the choice of IOL.

Changes in the Serum Level of High Density Lipoprotein-cholesterol after Smoking Cessation among Adult Men.

BACKGROUND: Smoking and obesity are known risk factors for cardiovascular diseases, while low serum levels of high density lipoprotein-cholesterol is an independent risk factor for mortality from ischemic heart diseases. This study examines changes in the serum level of high density lipoprotein-cholesterol depending on changes in the state of smoking and body mass index. METHODS: A survey and blood check-up were conducted on medical examination, along with acts of smoking among male adults of 25 years or older who visited the health promotion center of Daegu Medical Center from 2007 to 2010, and the results were analyzed. The subjects were divided into two different groups, current smokers and abstainers, and body mass index, total cholesterol, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, and triglycerides for three years were compared in both groups. Changes between the first and second visits in body mass index and lipid profiles of the two groups were compared to analyze changes after abstaining. RESULTS: The subject group which showed a significant increase in high density lipoprotein-cholesterol level was only abstainers whose body mass index had decreased by more than 0.5 kg/m(2). CONCLUSION: Smoking cessation increases serum levels of high density lipoprotein-cholesterol. If reduction of body mass index and smoking cessation are combined, the risk of cardiovascular disease will be lower in proportion to the increase in serum high density lipoprotein.

Effect of diastolic dysfunction on early outcomes during elective off-pump coronary artery bypass grafting: a prospective observational study.

BACKGROUND: Left ventricular diastolic dysfunction (DD) causes adverse outcomes after cardiac surgery; however, the effects of DD during off-pump coronary artery bypass grafting (OPCAB) are not well understood. We aimed to assess the influence of DD on early mortality and morbidity of patients undergoing OPCAB. METHODS: This prospective observational study included 1,256 patients scheduled for elective OPCAB. The DD of the patients was assessed by transthoracic echocardiography and tissue Doppler imaging. The cohort was classified into four DD groups; normal, mild (relaxation abnormality), moderate (pseudonormal dysfunction), and severe (restrictive abnormality). Study endpoints were major adverse cardiac events and other complications. Multivariate logistic regression was used to evaluate the independent effect of DD on surgical outcomes. RESULTS: The 1,256 patients were grouped as follows: normal diastolic function (n=55, 4.4%), mild DD (n=995, 79.2%), moderate DD (n=169, 13.5%), and severe DD (n=37, 2.9%). Operative strategy did not differ among groups. The prevalence of hypertension, diabetes mellitus, renal failure, low ejection fraction (<35%), myocardial infarction within 30 days, and European System of Cardiac Operative Risk Evaluation score greater than 5 increased significantly with more severe DD. No significant difference was found in 30-day major adverse cardiac events (normal, 1.8%; mild DD, 3.6%; moderate DD, 6.5%; severe DD, 5.4%; p=0.23); however, postoperative renal failure, respiratory complications, respiratory failure, and prolonged hospitalization (more than 12 days: 75th percentile of the study cohort) increased with the severity of DD (p<0.01). Multivariate analysis revealed that severe DD independently predicted respiratory complications (odds ratio 3.68, 95% confidence interval: 1.84 to 20.36, p=0.01) and prolonged hospitalization (odds ratio 5.75, 95% confidence interval: 1.81 to 13.23, p<0.01). CONCLUSIONS: Diastolic dysfunction does not affect 30-day major adverse cardiac events after elective OPCAB. However, severe DD independently predicts respiratory complications and prolonged hospitalization.

Correlation of akinesia with graft patency and cardiac enzyme after off-pump coronary artery bypass graft surgery.

BACKGROUND: The aim of the present study was to identify the clinical implications of newly developed akinesia in echocardiography after off-pump coronary artery bypass graft (CABG) surgery and its relationship with graft patency. METHODS AND RESULTS: A total of 512 patients underwent off-pump CABG from January 2007 to November 2008. Two hundred and thirty-nine patients, whose echocardiography and multi-slice computed tomography data were available, were included in the study. Wall motion was subdivided into 16 segments and analyzed. Patients were separated into group A with newly developed akinesia (n=20), and group B without newly developed akinesia (n=219). Morbidity and early mortality, cardiac enzyme level, and graft patency were compared. The incidence of newly developed akinesia according to the anatomical territory was as follows: anterior, 5; lateral, 3; posterior, 7; and multiple territories, 5. Significant differences in preoperative ejection fraction were observed between the 2 groups (group A, 45.0+/-7%; group B, 58.0+/-12.2%, P<0.001). There was no statistical difference in the mean number of bypassed grafts and the complete revascularization rate. Complication and early mortality rates were insignificant between the 2 groups. There was little association between graft patency, cardiac enzyme level, and newly developed akinesia (P>0.05). Multivariate analysis showed that the preoperative ejection fraction was a risk factor for newly developed akinesia. CONCLUSIONS: The mechanism of development of akinesia after off-pump CABG might be attributable to intraoperative coronary malperfusion, which is probably due to cardiac manipulation rather than graft occlusion.

A prospective study of blood pressure and intraocular pressure changes in hypertensive and nonhypertensive patients after intravitreal bevacizumab injection.

PURPOSE: To evaluate the changes in blood pressure and intraocular pressure (IOP) in patients with and without hypertension after intravitreal bevacizumab (Avastin) injection. METHODS: This study examined 135 (74 nonhypertensive vs. 61 hypertensive) consecutive patients treated with an intravitreal injection of 1.25 mg bevacizumab for retinal vascular diseases prospectively over a 6-month period. All the hypertensive patients were on medication, and only patients with controlled hypertension after consultation with cardiology specialists were included. Intraocular pressure and blood pressure were measured before and 30 minutes, 1 day, 1 week, 3 weeks, and then every month after the bevacizumab injection. RESULTS: The mean baseline systolic and diastolic pressures were significantly higher in the hypertensive group (systolic P = 0.001, diastolic P = 0.023). None of the systolic and diastolic values after injection differed significantly from the baseline values in the hypertensive group. By contrast, the 30-minute systolic values were significantly higher than baseline (P < 0.05), and the 1-day diastolic values were lower than before injection in the nonhypertensive group (P < 0.05). The mean baseline IOP of the nonhypertensive and hypertensive groups was similar (P = 0.08). The mean IOP 30 minutes after injection was significantly higher than the baseline mean IOP (P < 0.05), and the mean IOPs at 1 day and 1 week were significantly lower than before injection in both groups (P < 0.05). CONCLUSION: Intravitreal bevacizumab injection is safe in terms of blood pressure and IOP in both hypertensive and nonhypertensive patients after 6 months of follow-up.

Results of an extracardiac pericardial-flap lateral tunnel Fontan operation.

OBJECTIVE: Extracardiac pericardial-flap lateral tunnel Fontan operation has the theoretical advantage of growth potentiality of the extracardiac tunnels. The mid-term results of this technique and morphologic change of the lateral tunnel were studied. METHODS: Clinical data were reviewed in 42 patients who underwent extracardiac pericardial-flap lateral tunnel Fontan operation between November 1993 and December 2004. The age was 2.8+/-1.5 years and the body weight was 12.3+/-3.2kg. Extracardiac tunnel was constructed using the pedicled pericardium with the base undetached. By reviewing the follow-up cardiac angiograms (2.3+/-1.4 years postoperatively), ratios of diameter and cross-sectional area of the lateral tunnel to those of inferior vena cava were obtained. RESULTS: There were 4 surgical mortalities (10%). Postoperative morbidity included prolonged pleural effusion in 5 patients and heart block in 1 patient. Follow-up was possible in 37 patients and the follow up duration was 3.8+/-2.2 years. There were two late deaths due to ventricular dysfunction and sudden death of unknown causes. Two patients required reoperation due to subaortic stenosis and stenosis between inferior vena cava and lateral tunnel. In one patient, bradyarrhythmia was observed but there was no thromboembolic complication. Follow-up anteroposterior and lateral diameter ratio were 1.1+/-0.5 and 1.2+/-0.5. The cross-sectional area ratio was 2.6+/-2.3. In 5 patients, fusiform dilatation of the lateral tunnel was observed, but in the remaining patients, the lateral tunnel preserved tubular morphology with good hemodynamics. CONCLUSIONS: Extracardiac pericardial-flap lateral tunnel Fontan operation is relatively simple and feasible even in patients with previous median sternotomies. The mid-term results were acceptable, and the lateral tunnel demonstrated a tendency to preserve its tubular shape. However in some patients, dilatation of the pericardial-flap tunnel was observed during follow up. Longer follow-up is required to determine the morphologic changes of the lateral tunnel and the value of this technique.

Burst-shot infrared digital photography to determine scotopic pupil diameter.

PURPOSE: To evaluate the usefulness of infrared digital photography for determining scotopic pupil size by comparing infrared digital photography with a Colvard pupillometer (Oasis Medical). SETTING: Department of Ophthalmology, Ajou University School of Medicine, Suwon, Korea. METHODS: Scotopic pupil size in 50 eyes of 25 healthy individuals was measured with a Colvard pupillometer and a digital camera (DSC-F828) using infrared burst shots after 5 minutes of dark adaptation. Measurements were performed by 2 independent examiners (E1 and E2). The digital photograph images were read using the ruler function of Adobe Photoshop 7.0 by 2 independent readers (R1 and R2). Agreement and repeatability were analyzed using the comparison method described by Bland and Altman. RESULTS: The mean scotopic pupil diameter measured using the Colvard pupillometer was 6.69 mm +/- 0.78 (SD) (E1) and 6.70 +/- 0.71 mm (E2). The mean scotopic pupil diameter measured from the digital photograph images was 6.67 +/- 0.75 mm (E1) and 6.66 +/- 0.78 mm (E2). The mean difference between E1 and E2 with both devices was small; however, the result with the infrared digital camera was marginally smaller than with the Colvard pupillometer. The limits of agreement were -0.01 +/- 0.70 mm with the Colvard pupillometer and 0.01 +/- 0.20 mm with the digital photograph image. The digital photograph image showed better agreement. The coefficient of interrater repeatability was smaller for the digital photograph image (0.39) than for the Colvard pupillometer (0.70). CONCLUSIONS: Scotopic pupil measurement using an infrared digital camera with a burst shot had good agreement with the Colvard pupillometer and better repeatability. The infrared digital camera is less expensive, and pupil unrest can be overcome by taking serial images.