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Aphakia is the absence of the lens of the eye, due to surgical removal, such as in cataract surgery, a perforating wound or ulcer, or congenital anomaly. It causes a loss of ability to maintain focus ( accommodation ), high degree of farsightedness ( hyperopia ), [ 1 ] and a deep anterior chamber .
Aphakia is the absence of the natural crystalline lens. The aphakic state is usually due to surgery to remove a cataractous lens, but post-surgical aphakia is rare nowadays because of the ubiquity of intraocular lenses. Rarely, aphakia can be post-traumatic or congenital in nature.
The brightness of the Purkinje images can be determined using Fresnel's equation: = (′) / (′ +), where and ′ are the refractive indices before and after the reflecting surface.
Aphakia correction: High degree hypermetropia due to absence of lens (aphakia) is best corrected using intraocular lens implantation. [ citation needed ] Refractive lens exchange (RLE): A variation of cataract surgery where the natural crystalline lens is replaced with an artificial intraocular lens ; the difference is the existence of abnormal ...
Acute-onset anisocoria should be considered a medical emergency. These cases may be due to brain mass lesions, which cause oculomotor nerve palsy.Anisocoria in the presence of confusion, decreased mental status, severe headache, or other neurological symptoms can forewarn a neurosurgical emergency.
Aniseikonia due to uniocular aphakia is best corrected surgically by intraocular lens implantation. [4] Similarly retinal aniseikonia is corrected by treating causative retinal disease. [4] Note however that before the optics can be designed, first the aniseikonia should be measured.
Replacement of the lens as treatment for cataract can cause pseudophakic macular edema (‘pseudophakia’ means ‘replacement lens’). This could occur as the surgery involved sometimes irritates the retina (and other parts of the eye) causing the capillaries in the retina to dilate and leak fluid into the retina. This is less common today ...
Bullous keratopathy, also known as pseudophakic bullous keratopathy (PBK), is a pathological condition in which small vesicles, or bullae, are formed in the cornea due to endothelial dysfunction.