QuizWise 24

  1. Hypertension is a potential risk factor in all the following ocular diseases except?
    a. Retinal vein occlusion
    b. ARMD
    c. Glaucoma
    d. AION
  1. All the following are features of hypertensive retinopathy except-
    a. Focal arteriolar narrowing
    b. Arteriovenous nicking
    c. Hemorrhage and exudates
    d. Microaneurysms
  1. Which is one of the first changes to appear in eyes with systemic hypertension?
    a. Changes in the retinal nerve fiber layer in peripapillary region
    b. Changes in the ganglion cell layer in the macular region
    c. Disc hyperemia
    d. A-V changes
  1. Other than hypertension typical changes of hypertensive retinopathy can be caused by which of the following?
    a. Intima-media thickness
    b. Carotid plaque score
    c. Carotid artery stiffness
    d. Serum cholesterol concentration
    e. All of the above
  1. What is the initial response of the retinal circulation to a rise in systemic blood pressure?
    a. Retinal–arteriolar narrowing
    b. Vasospasm
    c. Opacification of arteriolar walls
    d. Compression of the venules by arterioles at their common adventitial locations

Answers

  1. d

Some have suggested that hypertension could increase the potential risk factor for age-related macular degeneration, on the basis of its purported effects on the choroidal circulation. An association between hypertension and risk of age-related macular degeneration has been noted in both cross-sectional and prospective data. The Blue Mountains study has shown that focal arteriolar narrowing, a marker of hypertensive retinopathy damage, was associated with the incidence of some signs of age-related macular degeneration.
Several pathophysiological mechanisms have been proposed to explain this putative association.

First, direct microvascular damage from systemic hypertension could impair blood flow to the anterior optic nerve. This notion is supported by studies linking glaucoma to abnormal ocular blood flow and narrowing of the retinal vasculature.

Second, hypertension could interfere with auto regulation of the posterior ciliary circulation, which is already impaired in glaucoma.

Third, antihypertensive treatment could induce hypotensive episodes, especially at night, which could reduce blood flow to the optic-nerve head, resulting in additional damage to the optic nerve. 

Fourth, other cardiovascular risk factors linked with hypertension (e.g., diabetes and cardiovascular disease) could affect vascular perfusion of the optic-nerve head. 

Finally, systemic blood pressure is closely related to intraocular pressure, the main risk factor for glaucomatous optic-nerve damage.

Reference: Wong TY, Mitchell P. The eye in hypertension. Lancet. 2007;369(9559):425‐435. DOI: 10.1016/S0140-6736(07)60198-6

  1. d

Features of hypertensive retinpathy according to different studies are-

StudyFocal arteriolar narrowing (%)Arteriovenous nicking (%)Haemorrhages and Exudates (%)
Cardiovascular health study9.67.68.3
Beaver Dam eye study13.52.27.8
Atherosclerosis risk in communities study14.914.33
Blue Mountains eye study7.98.9Not reported

Microaneurysms are a feature of Diabetic retinopathy, not hypertensive retinopathy.

Reference: van den Born, Bert-Jan H et al. Value of routine funduscopy in patients with hypertension: systematic review. BMJ (Clinical research ed.) vol. 331,7508 (2005): 73.  DOI: 10.1136/bmj.331.7508.73

  1. b

The thickness decrease was more prominent in the GC-IPL than in the peripapillary RNFL. Although it is difficult to definitively explain, the expected mechanism may be as follows. First, the ganglion cell layer is highly sensitive to acute, transient, and mild systemic hypoxic stress. Second, the ganglion cell bodies in the macular region are multi-layered and 10- to 20-fold thicker than their axons. Hence, changes in the ganglion cell layer may be easier to detect in the macular region than in the peripapillary area

Reference: Lim HB, Lee MW, Park JH, Kim K, Jo YJ, Kim JY. Changes in Ganglion Cell-Inner Plexiform Layer Thickness and Retinal Microvasculature in Hypertension: An Optical Coherence Tomography Angiography Study. Am J Ophthalmol. 2019;199:167‐176. DOI: 10.1016/j.ajo.2018.11.016

In both the Beaver Dam eye study and the Blue Mountains eye study little difference was found in the presence of haemorrhages and exudates between normotensive and hypertensive people aged over. Various other conditions have been associated with hypertensive retinopathy, such as ethnicity, smoking, intima-media thickness, carotid plaque score, carotid artery stiffness, serum cholesterol concentration, diabetes, and body mass index.

Reference: van den Born, Bert-Jan H et al. Value of routine funduscopy in patients with hypertension: systematic review. BMJ (Clinical research ed.) vol. 331,7508 (2005): 73. DOI: 10.1136/bmj.331.7508.73

  1. b

The initial response of the retinal circulation to a rise in blood pressure is vasospasm and an increase in vasomotor tone, which is seen clinically as generalised retinal–arteriolar narrowing. Subsequently, chronic arteriosclerotic changes, such as intimal thickening, media-wall hyperplasia, and hyaline degeneration, develop. These changes manifest as diffuse and focal areas of arteriolar narrowing, opacification of arteriolar walls (described as silver or copper wiring), and compression of the venules by arterioles at their common adventitial locations (termed arterio-venous nipping or nicking). With more pronounced high blood pressure, the blood–retinal barrier breaks down, resulting in exudation of blood (haemorrhages), lipids (hard exudates), and subsequent ischaemia of nerve-fibre layers  (known as cotton-wool spots). In the setting of severely high blood pressure, raised intracranial pressure and concomitant optic nerve ischaemia can lead to disc swelling (papilloedema), which is sometimes referred to as severe or malignant hypertension or hypertensive optic neuropathy.

Referance: Wong TY, Mitchell P. The eye in hypertension. Lancet. 2007;369(9559):425‐435. DOI: 10.1016/S0140-6736(07)60198-6

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