Related Experiment Video
Updated: Jan 29, 2026
07:18
Evaluation of Capillary and Other Vessel Contribution to Macular Perfusion Density Measured with Optical Coherence Tomography Angiography
Published on: February 18, 2022
2.2K
Changes in Optic Nerve Head Vessel Density After Acute Primary Angle Closure Episode.
Sasan Moghimi1,2, Mona SafiZadeh2, Masoud Aghsaei Fard2
1Hamilton Glaucoma Center, Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, San Diego, California, United States.
Investigative Ophthalmology & Visual Science
|February 6, 2019
Summary
Acute primary angle closure (APAC) reduces circumpapillary vessel density (cpVD) over six weeks. Retinal nerve fiber layer (RNFL) thickness initially increases then decreases after an APAC episode.
Area of Science:
- Ophthalmology
- Retinal Imaging
- Vascular Biology
Background:
- Acute primary angle closure (APAC) is a critical condition affecting ocular health.
- Understanding the microvascular and structural changes post-APAC is crucial for patient management.
Purpose of the Study:
- To investigate the longitudinal changes in circumpapillary vessel density (cpVD) and retinal nerve fiber layer (RNFL) thickness following an acute primary angle closure (APAC) episode.
Main Methods:
- Prospective observational study involving 28 patients with unilateral APAC and 39 controls.
- Optical coherence tomography angiography (OCTA) measured cpVD; spectral-domain optical coherence tomography (SD-OCT) measured RNFL thickness.
- Comparisons made at 1 and 6 weeks post-APAC between affected, fellow, and control eyes.
Main Results:
- At 6 weeks, APAC eyes showed significantly lower cpVD compared to fellow and control eyes (P < 0.001), with superonasal microvascular dropout.
- APAC eyes exhibited thinner RNFL globally and in most sectors at 6 weeks.
- Affected eyes had higher cpVD at 1 week than at 6 weeks (P = 0.003) but lower than fellow eyes (P < 0.001).
- RNFL thickness in APAC eyes was greater at 1 week than at 6 weeks (P = 0.037) and also greater than in fellow eyes at 6 weeks (P = 0.001).
Conclusions:
- Circumpapillary vessel density significantly decreases in the 6 weeks following an APAC episode.
- Retinal nerve fiber layer thickness shows a transient increase followed by a decrease in the weeks after APAC.
Related Concept Videos
01:28Angle Closure Glaucoma: Treatment
1.2K
Angle-closure glaucoma, or closed-angle glaucoma, is an eye condition where the iris bulges out and blocks the iridocorneal angle, resulting in a buildup of aqueous humor and increased intraocular pressure. Immediate medical attention is necessary due to the sudden onset of symptoms. The treatment for angle-closure glaucoma includes short-term and long-term approaches. Short-term treatment involves using eye drops like pilocarpine to lower intraocular pressure by increasing aqueous humor...
1.2K
01:13Contact Angle
19.2K
When a solid is dipped inside a liquid, the liquid surface becomes curved near the contact. For some solid–liquid interfaces, the liquid is pulled up along the solid, while for others, the liquid surface is convex or depressed near the solid surface. This phenomenon can be explained using the concept of cohesive and adhesive forces.
The adhesive force is the molecular force between molecules of different materials, that is, between the molecules of the solid and the liquid. The cohesive...
The adhesive force is the molecular force between molecules of different materials, that is, between the molecules of the solid and the liquid. The cohesive...
19.2K
01:27Open Angle Glaucoma: Treatment
993
In open-angle glaucoma, the iridocorneal angle remains open, but the trabecular meshwork becomes stiff, slowing down the outflow of aqueous humor. This causes a buildup of aqueous humor in the anterior chamber, leading to a sudden increase in intraocular pressure. The treatment for open-angle glaucoma focuses on reducing the elevated intraocular pressure by either decreasing the secretion of aqueous humor or increasing its outflow.
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drugs such as carbonic anhydrase inhibitors, α2- and...
993
01:19Muscles that Move the Head
5.8K
The muscles that move the head are a dynamic and complex group of structures that work together to facilitate a wide range of head movements, including rotation, flexion, extension, and lateral bending.
The bilateral sternocleidomastoid, or SCM, and the suprahyoid and infrahyoid muscles are significant head flexors. The SCM muscles originate at the sternum and clavicle and attach to the mastoid process of the temporal bone. The SCM contracts bilaterally to bend the head forward, whereas...
The bilateral sternocleidomastoid, or SCM, and the suprahyoid and infrahyoid muscles are significant head flexors. The SCM muscles originate at the sternum and clavicle and attach to the mastoid process of the temporal bone. The SCM contracts bilaterally to bend the head forward, whereas...
5.8K
01:13Angle of Twist: Problem Solving
784
An electric motor applies a torque of 700 N·m to an aluminum shaft, triggering a stable rotation. Two pulleys, B and C, are subjected to torques of 300 N·m and 400 N·m, respectively. The modulus of rigidity is provided as 25 GPa. With the knowledge of the length and diameter of each segment, the twist angle between the two pulleys can be computed. First, a section cut is made between pulleys B and C, and the cut cross-section is analyzed using a free-body diagram. Given that the torque...
784
00:56Density
19.8K
Density is an important characteristic of substances, crucial in determining whether an object sinks or floats in a fluid. Its SI unit is kg/m3, and its cgs unit is g/cm3. The density of an object helps in identifying its composition, and also reveals information about the phase of the matter and its substructure. The densities of liquids and solids are roughly comparable, consistent with the fact that their atoms are in close contact. However, gases have much lower densities than liquids and...
19.8K