Associating the biomarkers of ocular blood flow with lamina cribrosa parameters in normotensive glaucoma suspects. Comparison to glaucoma patients and healthy controls

Purpose To evaluate association between ocular blood flow biomarkers and lamina cribrosa parameters in normotensive glaucoma suspects compared to glaucoma patients and healthy controls. Methods A total of 211 subjects (72 normotensive glaucoma suspects, 70 with primary open-angle glaucoma and 69 controls) were included. Ocular blood flow biomarkers in ophthalmic artery, central retinal artery, as well as in nasal and temporal short posterior ciliary arteries were measured using colour Doppler imaging. Lamina cribrosa position was assessed by measuring its depth, deflection depth, lamina cribrosa shape index and its horizontal equivalent (LCSIH) on B-scan images obtained using optical coherence tomography. Results Ocular blood flow biomarkers in glaucoma patients were statistically significantly reduced when compared to healthy controls in peak systolic velocity (PSV) (P = 0.001 in ophthalmic artery and P<0.001 in central retinal artery) and mean flow velocity (Vm) (P = 0.008 in ophthalmic artery and P = 0.008 in central retinal artery), but not statistically significantly different to that of glaucoma suspects except for PSV in central retinal artery (P = 0.011). Statistically significant correlations corrected for age, central corneal thickness and intraocular pressure were found in glaucoma patients between LCSIH and end diastolic velocity of central retinal artery (P = 0.011), and of nasal short posterior ciliary artery (P = 0.028), and between LCSIH and Vm of central retinal artery (P = 0.011) and of nasal short posterior ciliary artery (P = 0.007). No significant correlations were observed between these parameters in glaucoma suspects and healthy controls. Conclusions Impaired ocular blood flow associated with the deformation of lamina cribrosa was found in glaucoma patients, whereas glaucoma suspects had similar lamina cribrosa shape to glaucoma patients but that deformation was not associated with ocular blood flow biomarkers.

Assessment of optic nerve vascularity in healthy eyes using superb microvascular imaging: a preliminary study

Background Changes in optic nerve vascularity are observed in many diseases. Superb microvascular imaging (SMI) has the potential to become the method of choice for detecting microvasculature in the optic nerves. Purpose To evaluate optic nerve vascularity in healthy individuals through power Doppler sonography (PDUS) and SMI. Material and Methods Twenty-seven healthy patients with 54 eyes were prospectively evaluated. The duration of the examination for optic nerve vascularity lasted until the posterior ciliary artery blood supply was observed in PDUS and SMI. The visibility of vascularity, as well as the ratio of the vascular structures to the optic nerves (vascular index [VI]), was evaluated. Results Fifty-four eyes were evaluated from a total of 27 patients (mean age = 49.0 ± 19.42 years). The VI value for the right optic nerve was 29.58 ± 4.00 while for the left optic nerve, it was 31.21 ± 3.52. Vascularity was clearly observed in both eyes (n = 54) in all 27 cases in the evaluation performed with the SMI technique. However, with the power Doppler examination, vascular flow was not observed in 14 right eyes and in 10 left eyes within the specified timeframe. Conclusion The results indicate that imaging of vascular structures can be done faster and better with SMI than PDUS examination. The normal VI values may provide important information about the blood supply of the optic nerve, which is of relevance in orbital pathologies and many systemic conditions.

Inflammation of a Posterior Ciliary Artery in a Naive Cynomolgus Macaque

This brief communication describes a previously unreported background lesion in the eye of a naive cynomolgus macaque. Inflammation of a posterior ciliary artery was, in this case, morphologically similar to vascular inflammation of other tissues described in naive cynomolgus macaques. However, the available literature does not describe this lesion at this anatomical site. The affected animal did not present with any abnormal clinical signs and ophthalmological examinations were within normal limits. Toxicologic pathologists should be aware of this finding in order to help differentiate it from a test item–related finding.

The effect of moderate treadmill exercise on the resistive index of the medial long posterior ciliary artery in dogs

The resistive index (RI) is an indirect measurement of arterial resistance by means of a ratio between the peak systolic and end diastolic velocities recorded with a spectral Doppler device, especially used to evaluate the vascular damage in ocular diseases such as glaucoma. Some ocular variables such as the intraocular pressure (IOP), the choroidal thickness, the axial length and the ocular blood flow may be influenced by physical exercise. The purpose of this study was to evaluate the influence of the exercise on the RI of the medial long posterior ciliary artery in dogs, and correlate the data obtained with the IOP values. Ten clinically healthy dogs were subjected to moderate physical exercise on a canine motorised treadmill at different speeds for 45 minutes. A colour Doppler examination was performed and the RI values were calculated for the medial long posterior ciliary artery at rest, immediately after the exercise, and after 60 minutes at the end of the exercise. At the same times, the IOP was recorded by applanation tonometry. The data were analysed by a two-way repeated ANOVA measurement in order to compare the RI and the IOP. Wilcoxon’s test was applied for the post hoc comparison. Spearman’s rank correlation for non-normal distribution was used to determine a relationship between the RI and the IOP. The at rest RI was 0.722 +/–0.022, IOP 12.38 +/3.21 mm Hg. A significant decrease in the RI was observed immediately after the exercise (0.697 +/–0.035) and during the passive recovery phase (0.682 +/–0.042). A significant decrease in the IOP (11+/3.39 mmHg) was recorded after 60 min of the passive recovery phase; at the end of the exercise, a slight decrease (12.29+/4.26 mm Hg) mm Hg was detected. During the test, a linear correlation between the RI and the IOP was observed. Our results suggest that exercise induces the modification of the ophthalmic blood flow in dogs, presumably related to the compensatory neuro-hormonal mechanisms.

Tangential Scleral Myopexy (TSM) as an Alternative to Muscle Resection in Strabismus Treatment

To present the new method as a variant of minimal invasive strabismus surgery (MISS) technique for less invasive and faster reсtus muscle plication. Extraocular muscle strengthening is common for strabismus treatment. Plication as an alternative for tightening or strengthening muscles appears to be less traumatic, quicker and vascular preserving operation. A new plication variant performed by fixating the edge of muscle with 6-0 vicril sutures and pulling them forward and oversewn at 2–3 mm from external part sclera-tendon joint avoiding the anterior ciliary artereies. The distance of muscles advancement depends on the eye deviation angle and calculated by Kenneth Wright charts. In all patients fornix transconjunctival access was performed. Proposed trapezoidal scleral myopexy (TSM) was performed in 26 patients at the age from 3 to 32 years old (children 3–15 y.o. = 29; adults 20–32 y.o. = 7). 23 consecutive patients underwent TSM combined with antagonist recession at the same eye (15 esotropia, 11 exotropia). Follow up period was 6–26 months. The results were considered satisfactory if the postoperative angle was between 0 ± 3° (92.3 %). Only 2 cases (7.6 %) failed to reach this standart. The obtained results considered as very satisfactory. Patients reported only minimal postoperative discomfort and no complain on cosmetics. Trapezoidal muscle plication was inconspicuous throught the conjunctive. The good results of TSM proposed by the author seems to be very simple and more effective for muscle strengthening comparing to resection of medial and lateral rectus muscles. Placement of sutures at the muscle edge during trapezoidal plication exclude ciliary vassel destruction and anterior segment ischemia. The obtained results demonstrated that TSM was considered to be equivalent to resection of horizontal rectus and especially of vertical rectus muscles. Trapezoid form of plication increases the arc of sclera contact to the muscle, probably, explaining the efficiency of proposed operation for muscle strengthening. Proposed modification of muscle plication is reversible, simple, sparing for ciliary artery procedure and is recommended as minimal invasive strabismus surgery (MISS) for simultaneous operation on multiple rectus muscles.