diabetic retinopathyNonproliferative - damaged capillaries leak blood → lipids and fluid seep into retina (hard exudates) → hemorrhages and macular edema, which can distort vision. Arteriolar obstruction cause ischemic injury → ☆cotton-wool spots
+☆microaneurysm, dot-blot hemor
Treatment: blood sugar control.
Proliferative - chronic hypoxia results in new blood vessel formation with resultant traction on retina → retinal detachment. Treatment: anti-VEGF injections, peripheral retinal photocoagulation, surgery. ophthalmologyUWorld Jul 7, 2020, 11:15 PM HirotoShishido
Pictureleft: "blood and thunder appearance"
→ retinal vein occlusion
right: macular star (exudate, red arrow), cotton-wool spots (blue arrow)
Retinal damage due to chronic uncontrolled HTN. Presence of papilledema requires immediate lowering of BP. ophthalmology Jul 7, 2020, 5:50 AM HirotoShishido
closed angle glaucoma vs migrane with auraclosed angle glaucoma
→ typically older (> 60yo),
severe pain and conjunctival erythema are common, and vision would not be expected to improve without intervention
mechanism of sorbitol accumulationThe first step in the polyol pathway is the conversion of glucose into sorbitol by aldose reductase. Sorbitol cannot readily cross cell membranes and is therefore trapped inside the cells where it forms.
The second enzyme in the pathway, sorbitol dehydrogenase, is able to convert sorbitol into ☆fructose at a sufficient rate to prevent accumulation when glucose levels are normal.
symptoms/signs/pathogenesis of cataract・Gradual loss of visual acuity
・Excessive glare, halos around bright lights
・Myopic shift
・Opacification of lens
・Loss of red reflex
・Photooxidative damage
Cumulative photooxidative stress is worsened by heavy UV exposure (eg, outdoor occupations), smoking, or ionizing radiation.
・Nuclear sclerosis
・Osmotic injury
accelerated in patients with diabetes mellitus ophthalmologyUWorld May 18, 2020, 9:37 PM HirotoShishido
Pictureoptic disk atrophy with characteristic cupping=thinning of outer rim of optic nerve head
→glaucoma
cherry red spot(☆bright red fovea centralis surrounded by a contrasting white macula→ central retinal artery occlusion, metachromatic leukodystrophy, Niemann-Pick, Tay-Sachs)
latanoprost/ iloprost
mechanismlatanoprost→
prostaglandins
☆↑outflow of aqueous humor via uveoscleral pathway
treatment of glaucoma
iloprost→
prostacyclin
direct vasodilatory effects on pulmonary and systemic arterial vascular beds, inhibit platelet aggregation ophthalmologypharmacologyUWorld Apr 12, 2020, 11:37 AM HirotoShishido
adverse effect to ciliary muscle
of α-agonists, β-blockers, cholinomimeticsα-agonists (naphazoline)(↓aqueous humor synthesis (α2))→cannot used for closed angle glaucoma due to ☆mydriasis (α1)
β-blockers (timolol) decrease aqueous humor synthesis (β2) in ☆ciliary epithelium→ no pupillary or vision changes
