Pulsatile ocular blood flow change after treatment with systemic steroid in patients with Graves' ophthalmopathy

Do ocular pulse amplitude and choroidal thickness change in patients with thyroid eye disease?

Purpose: The aim of this study was to evaluate whether orbital changes induced by thyroid eye disease affect the ocular pulse amplitude and choroidal perfusion. Materials and Methods: A total of 38 eyes of 38 patients with thyroid eye disease (Group 1) and 38 eyes of 38 control individuals (Group 2) with normal intraocular pressure were enrolled in this study. Thyroid eye disease activity was defined using clinical activity score. Intraocular pressure measurement with Goldmann applanation tonometer, axial length, central corneal thickness, Hertel exophthalmometry and systolic and diastolic blood pressure measurements were taken from each patient. Ocular pulse amplitude and intraocular pressure were measured using dynamic contour tonometry. Choroidal thickness was measured by enhanced depth imaging-optical coherence tomography at subfoveal, nasal and temporal 1000 μm area. Results: Intraocular pressures measured with Goldmann applanation tonometer and dynamic contour tonometry and mean ocular pulse amplitude were not statistically different between groups. However mean choroidal thicknesses were significantly lower when compared to control group. Ocular pulse amplitude and intraocular pressure measurement with dynamic contour tonometry did not change significantly with the increase in clinical activity score. There was not statistically significant correlation between ocular pulse amplitude and choroidal thicknesses in patients with thyroid eye disease. Conclusion: Ocular pulse amplitude and choroidal perfusion were not found to change with orbital involvement in thyroid eye disease and with disease activity, especially in patients with normal intraocular pressure. Although choroidal thickness was thinner than control group, choroidal perfusion did not change as a compensatory mechanism for maintaining ocular homeostasis.

Short-term effects of intravitreal triamcinolone acetonide injection on ocular blood flow evaluated with color Doppler ultrasonography

AIM

To evaluate the changes in ocular blood flow with color Doppler ultrasonography (CDU) after intravitreal triamcinolone acetonide (IVTA) injection.

METHODS

A total of 46 patients who underwent IVTA (4 mg/0.1 mL) injection for diabetic macular edema (DME) (n=22), central retinal vein occlusion (CRVO) (n=12) and choroidal neovascular membrane (CNVM) (n=12) were included in the study. Peak systolic velocity (PSV), end diastolic velocity (EDV) and resistivity index (RI) were measured from the ophthalmic artery (OA), the central retinal artery (CRA) and the posterior ciliary artery (PCA) of each patient with CDU before, at the end of the first week and at the end of the first month following IVTA injection.

RESULTS

In the DME group, PSV of OA at the first of the first month (mean±SD) (37.48±10.87 cm/s) increased compared to pre-injection value (31.39±10.84 cm/s) (P=0.048). There was a statistically significant decrease (P=0.049) in PSV of CRA at the end of the first month (7.97±2.67 cm/s) compared to the pre-injection (9.47±3.37 cm/s). There was not any statistically significant difference on the other parameters in the DME group. Also, there was not any statistically significant difference on the ocular blood flow values in the CRVO and CNVM groups.

CONCLUSION

We observed that 4 mg/0.1 mL IVTA increased PSV of OA and decreased PSV of CRA in DME patients and did not have any effect on ocular blood flow values of CRVO and CNVM patients.

Effects of phacoemulsification surgery on ocular hemodynamics

AIM

To evaluate the possible effects of phacoemulsification cataract surgery on ocular hemodynamics.

METHODS

In this prospective study, intraocular pressure (IOP), pulsatile ocular blood flow (POBF), and ocular pulse amplitude (OPA) were measured pre-operatively (baseline) and at 1 week and 3 weeks postoperation in 52 eyes of 26 patients (mean age 63.15±10.25 years) scheduled for unilateral phacoemulsification cataract surgery with intraocular lens implantation. In all of the eyes, a blood flow analyzer (Paradigm DICON; Paradigm Medical Industries Inc.; USA) was used to obtain measurements of IOP, POBF, and OPA. The data obtained from operated eyes were compared statistically to untreated fellow phakic eyes of the patients.

RESULTS

For operated eyes, the mean baseline IOP, POBF, and OPA values were 15.9±4.64mmHg, 17.41±4.84µL/s, and 2.91±1.12mmHg, respectively. The IOP, POBF, and OPA values were 17.19±4.34mmHg, 17.56±6.46µL/s, and 3.12±1.1mmHg, respectively, in the nonoperated control eyes. Statistically significant differences from baseline measurements were not observed 1 week and 3 weeks postoperation for the operated or nonoperated eyes. There were also no statistically significant differences in any measurements between the operated and nonoperated eyes in all the examination periods (P>0.05 for all).

CONCLUSION

Uncomplicated phacoemulsification surgery does not affect ocular hemodynamics in normotensive eyes with cataracts.

Hemodynamic response to intravitreal triamcinolone in eyes with macular edema

PURPOSE

To assess ocular hemodynamic response to intravitreal triamcinolone in patients with macular edema due to diabetes or retinal vein occlusion.

METHODS

Forty-three patients that were injected by intravitreal triamcinolone acetonide (0.1 cc 4 mg) for unilateral macular edema due to diabetes mellitus (n = 17) and occlusion of retinal vein (n = 26) underwent ocular hemodynamic evaluation by color Doppler imaging (CDI) before and one, two and three months after injection. Non-injected fellow eyes as well as 16 healthy volunteers were also evaluated.

RESULTS

In patients with diabetic macular edema, there was no hemodynamic difference between eyes to be injected and non-injected at baseline (P > 0.23). Compared to controls, a significant difference existed in the ophthalmic artery resistant index (P = 0.001) and end-diastolic velocity (P < 0.001) in diabetics. At one month, compared to fellow eyes, change in end diastolic velocity from baseline in treated eyes was significantly decreased in posterior ciliary arteries (0.68 +/- 0.34 cm/s [mean +/- SEM] vs. -1.04 +/- 0.81 cm/s, P = 0.012). Throughout the study period, no significant alteration from baseline in the resistant index of any artery was noted in treated diabetic eyes (P > 0.05). In eyes with retinal vein occlusion, baseline CDI evaluation demonstrated reduced posterior ciliary arteries systolic flow velocity compared to fellow and control eyes (13.24 +/- 1.04 cm/s, 16.37 +/- 0.76 cm/s and 14.33 +/- 1.41 cm/s, respectively, P = 0.007). Increased peak systolic velocity in the posterior ciliary arteries at one week (P = 0.02), one month (P = 0.005) and two months (P = 0.04), and increase in central retinal artery resistant index at one month was noted (P = 0.05).

CONCLUSION

Intravitreal triamcinolone temporarily changed central retinal artery blood flow and posterior ciliary arteries' peak systolic blood velocity in eyes with retinal vein occlusion whilst no response of blood flow to triamcinolone injection but only transiently altered end diastolic blood velocity in posterior ciliary arteries was observed in diabetic eyes.

Technical note: How many readings are required for an acceptable accuracy in pulsatile ocular blood flow assessment?

PURPOSE

Pulsatile ocular blood flow (POBF) assessment aids the diagnosis of ocular diseases with defective ocular haemodynamics, such as glaucoma. Although each successful POBF measure given by the instrument represents five 'repeatable' pulses, there has been no study verifying how repeatable they are. There is also no report on the minimal number of measurements for an acceptable accuracy.

METHODS

Forty-three healthy young subjects were recruited and each subject had five consecutive POBF measurements obtained from one randomly selected eye. The coefficient of variation was calculated from the raw data of the five 'repeatable' pulses. The average from five consecutive measurements was considered as the standard for comparison with the first, average of the first two, the first three and the first four measurements. The 95% limits of agreement were determined using the Bland and Altman approach.

RESULTS

The coefficient of variation was greater than the manufacturer's claim of within 10%. The mean (+/-S.D.) POBF calculated from five consecutive measures was 732.5 +/- 243.2 microL min(-1). The mean (+/-S.D.) difference between the standard POBF and the first, average of the first two, the first three and the first four measurements was (in microL min(-1)): 12.5 +/- 59.8, 7.8 +/- 42.1, 9.6 +/- 32.5 and 3.7 +/- 19.6 respectively. The corresponding 95% limits of agreement were (in microL min(-1)): +/-117.2, +/-82.6, +/-63.8 and +/-38.4 respectively.

CONCLUSIONS

As the five 'repeatable' pulses were not as repeatable as the manufacturer claims, practitioners should not rely on one single POBF measure. An average of three consecutive measurements will be adequate to detect the minimum reported difference in POBF between glaucoma and normal patients.