Eye Doc

  Lensometer is a device that is used to measure the actual prescription of refractive error on which the glasses are made. Using this link you can practice and refine your lensometer skills by accuratly measuring the prescription of the glasses for comfortable eyes.

  Now you can practice Squint examination by using variable target and an occluder to test the behaviour of the strabismic eye and use prisms to measure the prism diopters of strabismus.  To Open the simulator click here

Human Lens Lens of a human eye is a transparent, biconvex, crystalline structure  It is composed of water (65%) and proteins (34%)                  Protein Content of lenses Higher than that of any organ of the body It consists of following types  -Water Soluble or Crystallins -Alpha crystallins _31.7% -Beta crystallins _53.4% -Gamma crystallins _1.5% -Water Insoluble or Albuminoids  Alpha-crystallins   -Having highest molecular weight (10)6  -M.W. of A chain – 19,500 -M.W. of B chain – 22,500 -α-Crystallins is a polymer compound and is made by fifty monomers.   Beta-crystallins -M.W. – 5x104 to 2x105 -β-Crystallins have high thiol concentration & disulphide bond linkage Gamma-crystallins  -These are the smallest crystallins. -Composed of monomers only. -Gamma-crystallin level is high in nucleus of the lens than its cortex. -Having four fraction which are immunologically identical except fraction II...

Bergmeister's papilla is a structure that arises from the center of the optic disc, consists of a small tuft of fibrous tissue and represents a rudementary fetal hyaloid artery. The hyaloid artery offers nutrients to the lens at some degree of early development inside the fetal eye, and runs forward to the lens from the optic disc.The optic disc is included by means of using a plaque of fibrous cells known as the central supporting tissue meniscus of Kuhnt . This plaque forms a fibrous sheath across the hyaloid artery wherein it leaves the optic disc. At the time of delivery of the infant the hyaloid artery regresses, and is generally absolutely regressed by the time of eyelids opening. Bergmeister's papilla is a remnant of the hyaloid artery fibrous sheath and is regularly located as an incidental finding. Bergmeister's papilla is referred to after Austrian ophthalmologist O. Bergmeister (1845–1918).

  The Mittendorf dot, determined by William Frederick Mitttendorf, is a congenital vascular abnormality of eye which takes place because of an involutional fault of the anterior terminus of anterior hyaloid artery. It manifests as a focal opacity in the infero-nasal element of the posterior lens capsular surface. It is a scientific version of persistent fetal vasculature (PFV), a spectrum of situations that rise up whilst fetal hyaloid vasculature fails to involute. The Mittendorf dot is concept to be connected to the posterior lens capsular surface itself; current research suggests the opportunity of a retrolental presence of the dot inside the anterior vitreous. A lone Mittendorf dot is a exceptionally benign clinical finding and no inflicting any visual impairment

A crystalline lens subluxation can be associated with multiple systemic factors and hence systemic evaluation is required fin addition to just eye examination. Some systemic factors that cause lens subluxation have been mentioned on another post of this website. So the systemic investigations will be the following.   CBC - due to increased incidence of thormboembolic events in general anesthesia. Serum or urine homocystein levels - to rule out homocysteinurea. VDRL - So lens subluxation caused by syphilis. Echocardiography - The ejection fraction must be adequate for patient to be operated under general anesthesia.

A subluxated lens is a condition in which the natural lens of a human eye is moved from its original position and thus causes decreased vision due to eccentric focusing of light directed towards fovea which is main focal point of vision in human eye. Lens subluxation is caused by many factors like trauma to the eyeball or any syndrome. Some of the syndromes that cause lens subluxation are as follows:  Marfan Syndrome Ehler Danlos Syndrome Weil Marchesani Syndrome Pseudoexfoliation Syndrome Syphilis Metabolic syndromes like homocysteinurea, hyperlysinemia.