Retrobulbar hemodynamic effects of nipradilol in normal and normal-tension glaucoma eyes.

Purpose. To investigate the effects of nipradilol on retrobulbar hemodynamics. Methods. We investigated normal and normal-tension glaucoma (NTG) eyes. Topical nipradilol (one eye) and placebo eye drops (fellow eye) were instilled for 1 week in volunteers. Nipradilol was also instilled in NTG patients. Ultrasound color Doppler imaging for the posterior vessels was performed before, 2 hr, 1 week (for normal), and at 4 weeks (for NTG). Results. In normal eyes, there were significant decreases in the resistance index (RI) for the temporal short posterior ciliary arteries (PCA) at 2 hr and for the ophthalmic arteries at 1 week. There were no significant changes in the placebo-treated eyes. In the NTG eyes, there was a significant decrease in the RI for the central retinal artery, nasal, and temporal PCA at 2 hr and 4 weeks. Conclusion. Short-term observations found that nipradilol increased the ocular blood flow in normal and NTG eyes.

Retinal Nerve Fiber Layer Decrease during Glycemic Control in Type 2 Diabetes.

Purpose. To assess an effect of glycemic control on retinal nerve fiber layer (RNFL) in type 2 diabetes mellitus. Methods. Thirty-eight eyes of 38 patients with type 2 diabetes undergoing blood glucose regulation were enrolled. All patients were examined at (1) initial visit, (2) 1 month, (3) 2 months, and (4) 4-month after the initial examination. On each occasion, glycosylated hemoglobin (HbA1c) levels and optical coherence tomography (OCT) scanning for RNFL thickness were evaluated. 360 degree circular OCT scans with a diameter of 3.4 mm centered on the optic disc were performed. Results. Significant RNFL decrease was seen in the superior area between initial and 4 months examination (P = .043). The relationship between the changes in HbA1c and the changes in RNFL thickness was observed in superior, temporal, and inferior area (P < .05) at 4 months. Conclusions. This study suggests that the glycemic control affects RNFL within 4 months.

Detection of early diabetic change with optical coherence tomography in type 2 diabetes mellitus patients without retinopathy.

PURPOSE: To detect early diabetic damage in type 2 diabetes mellitus patients with no diabetic retinopathy (NDR) using optical coherence tomography (OCT) and to evaluate OCT as a clinical test. METHODS: Thirty-two patients with NDR (n = 32) were enrolled. We examined retinal and retinal nerve fiber layer (RNFL) thickness using OCT. Two healthy normal populations were also enrolled for the retinal thickness (n = 48) and RNFL thickness (n = 34). Both OCT measurements were obtained in four areas (temporal, superior, nasal and inferior). The receiver operator characteristic (ROC) curve was generated to evaluate the predictor variables. RESULTS: Comparing the normal and NDR eyes, retinal thickness significantly increased (p = 0.03) and RNFL thickness significantly decreased (p = 0.02) in the superior areas. The area under the ROC curve was 0.65 for the superior retinal thickness and 0.63 for the superior RNFL thickness. CONCLUSIONS: Both OCT measurements can detect early retinal damage in NDR patients.

Effects of scleral buckling without encircling procedures on retrobulbar hemodynamics as measured by color Doppler imaging.

OBJECTIVE: To study the effects of segmental scleral buckling without encircling procedures on retrobulbar hemodynamic conditions using color Doppler imaging. METHODS: In 65 consecutive eyes of 65 patients with unilateral rhegmatogenous retinal detachment repaired by scleral buckling, we prospectively measured the blood flow velocities in the ophthalmic artery, central retinal artery, and short posterior ciliary artery using color Doppler imaging before and 2, 12, and 24 weeks after surgery. Peak systolic velocity (PSV) and end diastolic velocity (EDV) (calculated in centimeters per second) were measured using color Doppler imaging. RESULTS: The PSV and EDV in the ophthalmic artery were not changed significantly during follow-up. The PSV and EDV in the central retinal artery were reduced temporarily at 2 weeks after surgery, but at 12 weeks after surgery had returned to presurgery levels. The PSV and EDV in the short posterior ciliary artery on both sides continued to decrease postoperatively, and the reductions became statistically significant by 24 weeks after surgery (buckled side: P=.001 for PSV and P=.002 for EDV; unbuckled side: P<.001 for PSV and P=.004 for EDV). The decreases of PSV and EDV in the short posterior ciliary artery on the buckled side were positively correlated with the subject's age (R = 0.40, P = .001 for PSV; and R = 0.32, P = .008 for EDV). CONCLUSIONS: Scleral buckling procedures can cause subclinical disturbance of the choroidal circulation, even if encircling procedures are avoided. Aging is one of the risk factors for the disturbance.

Macular thickness measurements in healthy subjects with different axial lengths using optical coherence tomography.

PURPOSE: To evaluate the retinal thickness of the macula in healthy subjects with different axial lengths. METHODS: Included were 203 healthy subjects (116 males and 87 females). The axial length of the eyes ranged from 22.68 to 30.22 mm. Four optical coherence tomograms were obtained in a radial spoke pattern centered on the central fovea. Retinal thickness was calculated from the inner and outer retinal boundaries. The average retinal thickness in three circular areas surrounding the central fovea (350, 1,850, and 2,850 microm in diameter) was determined. RESULTS: The retinal thickness in the three circular areas was not significantly correlated with the axial length of the eye (P = 0.10, P = 0.39, and P = 0.12). There also was no statistically significant difference found between the average thickness in emmetropic and low myopic, mildly myopic, and highly myopic eyes in the three circular areas (P = 0.35, P = 0.38, and P = 0.14). CONCLUSION: When eyes with pathologic myopia were excluded, the axial length of the eye was found not to influence the average retinal thickness in the macular area.