Biomechanical homeostasis in ocular diseases: A mini-review

Myopia, also known as short-sightedness or near-sightedness, is a very common condition that typically starts in childhood. Severe forms of myopia (pathologic myopia) are associated with a risk of other associated ophthalmic problems. This disorder affects all populations and is reaching epidemic proportions in East Asia, although there are differences in prevalence between countries. Myopia is caused by both environmental and genetic risk factors. A range of myopia management and control strategies are available that can treat this condition, but it is clear that understanding the factors involved in delaying myopia onset and slowing its progression will be key to reducing the rapid rise in its global prevalence. To achieve this goal, improved data collection using wearable technology, in combination with collection and assessment of data on demographic, genetic and environmental risk factors and with artificial intelligence are needed. Improved public health strategies focusing on early detection or prevention combined with additional effective therapeutic interventions to limit myopia progression are also needed.

To assess whether a low cerebrospinal fluid pressure (CSF-P) is associated with open-angle glaucoma in eyes with normal intraocular pressure (IOP). Prospective, interventional study. The study included 43 patients with open-angle glaucoma (14 with a normal IOP, and 29 with an elevated IOP) and 71 subjects without glaucoma. All patients underwent standardized ophthalmologic and neurologic examinations and measurement of lumbar CSF-P. Cerebrospinal fluid pressure and IOP. Lumbar CSF-P was significantly (P<0.001) lower in the normal IOP glaucoma group (9.5+/-2.2 mmHg) than in the high IOP glaucoma group (11.7+/-2.7 mmHg) or the control group (12.9+/-1.9 mmHg). The trans-lamina cribrosa pressure difference (IOP minus CSF-P) was significantly (P<0.001) higher in the normal IOP glaucoma group (6.6+/-3.6 mmHg) and the high-IOP glaucoma group (12.5+/-4.1 mmHg) than in the control group (1.4+/-1.7 mmHg). The extent of glaucomatous visual field loss was negatively correlated with the height of the CSF-P and positively correlated with the trans-lamina cribrosa pressure difference. In the control group, CSF-P was significantly correlated with both systolic blood pressure (P = 0.04) and IOP (P<0.001). The trans-lamina cribrosa pressure difference was not significantly associated with blood pressure (P = 0.97). In open-angle glaucoma with normal IOP, CSF-P is abnormally low, leading to an abnormally high trans-lamina cribrosa pressure difference. Pathogenetically, a low CSF-P in normal-IOP glaucoma may be similar to a high IOP in high-IOP glaucoma. Consequently, the glaucomatous visual field defect is positively correlated with the trans-lamina cribrosa pressure difference and inversely correlated with the CSF-P. In nonglaucomatous subjects, CSF-P, blood pressure, and IOP are significantly associated with each other. Copyright (c) 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Diabetes mellitus (DM) is a complex metabolic disorder arising from lack of insulin production or insulin resistance (Diagnosis and classification of diabetes mellitus, 2007). DM is a leading cause of morbidity and mortality in the developed world, particularly from vascular complications such as atherothrombosis in the coronary vessels. Aldose reductase (AR; ALR2; EC 1.1.1.21), a key enzyme in the polyol pathway, catalyzes nicotinamide adenosine dinucleotide phosphate-dependent reduction of glucose to sorbitol, leading to excessive accumulation of intracellular reactive oxygen species (ROS) in various tissues of DM including the heart, vasculature, neurons, eyes, and kidneys. As an example, hyperglycemia through such polyol pathway induced oxidative stress, may have dual heart actions, on coronary blood vessel (atherothrombosis) and myocardium (heart failure) leading to severe morbidity and mortality (reviewed in Heather and Clarke, 2011). In cells cultured under high glucose conditions, many studies have demonstrated similar AR-dependent increases in ROS production, confirming AR as an important factor for the pathogenesis of many diabetic complications. Moreover, recent studies have shown that AR inhibitors may be able to prevent or delay the onset of cardiovascular complications such as ischemia/reperfusion injury, atherosclerosis, and atherothrombosis. In this review, we will focus on describing pivotal roles of AR in the pathogenesis of cardiovascular diseases as well as other diabetic complications, and the potential use of AR inhibitors as an emerging therapeutic strategy in preventing DM complications.