Think Tank

Embryology of the human Eye

The human eye anatomically is considered as an extension of the brain.the central nervous develop from the neural tube.A thickening appears on either sides of the neural tube in its anterior part known as OPTIC PLATE.The optic plate grows as the Foetus(baby) grows towards the surface to form the OPTIC VESICLE.the two eyes develop from these two optic vesicles.the neural ectoderm and mesoderm come together to form the optic vesicles.
As the foetus grows the optic visicles invaginates from in front and below to form the OPTIC CUP. there is a line of invagination that remains open  for sometime known as the embryonic fissure.the hyloid artery enters through the fissure to provide nutrients to the developing structures.later atrophies found dissapears.
The inner layer of the retina(main) is formed by the inner layer of the optic cup whiles the outer layer develops into the pigmented epithelium.the neural ectoderm is responsible for the secretion of the jelly-like fluid called the VITREOU…
Tears are secreted by the main and accessory lacrimal glands and pass laterally accross the ocular surface then evacuated through the canaliculus into the lacrimal sac,nasolacrimal duct and finally into the nose through the valve of Hasner. A variable amount of the tear film is lost through evaporation depending on the ambient temperature,humidity,and the rate of blinks per minute. An inefficiency in any may result in either dry eyes or watering eyes.its worth to know that any abnormal anatomy of the eye or morbidity may also result in watering eyes.
General signs and symptoms note:signs are cause specific and may include multiple features of the underlining anormaly profuse tearingpain,rednes,swelling and epihora at the medial canthus in cases of dacrocystitis painless swelling in the inner canthus(mucocele)  accumulation of sulphur granules in the canthusincomplete blinks and reduced blinking rateredness of the eyecongestion and redness of the eyelid maginsswollen eyelids C…


 ALLERGIES AND PHOTOKERATITIS  CHRISTMAS is here again,snow is falling once again,the weather is cold.... As family and friends enjoy the best of summer,others cannot wait for it to pass by.Medically,some people are very reactive to the presence of snow flakes and seasonal changes in the weather patterns.  Photokeratitis is a painful eye condition that occurs when your eye is exposed to invisible rays of energy called ultraviolet (UV) rays, either from the sun or from a man-made source.
Photokeratitis can be caused by sun reflection from sand, water, ice and snow. It can also happen if you stare at the sun, such as watching a solar eclipse directly without using a special device. A solar eclipse can also cause a burn to the retina, which is long lasting and more serious than temporary corneal damage.
There are also many man-made sources of ultraviolet light, including tanning lamps and tanning beds, as well as arc welding.

Snow blindness: a common form of photokeratitis Snow bli…


Huraaaaay!  Summer is here once again...... Enjoy the best of every moment with your family and friends . Summer with all the fun that comes seasonally with it, brings many medical conditions that causes discomforts in the life of many individuals who fall a victim to the season due to their body's reaction to the weather . As many cant wait for summer to come,others fear for the seasons return because of their eye ALLERGIES that  recurrently occurs every summer ;medically its called VERNAL  KERATOCONJUNCTIVITIS (spring catarrh).

Allergies are simply a hypersensitivity reaction of the human body following exposure to noxious stimuli in the environment.(pollen,dust,smoke,snow,perfumes,contact lenses,drugs,surgical sutures etc).Allergens as type 1 (immediate ) hypersensitivity reaction resulting in the secretion of eosinophils and mast cell degranulation causing inflamation,itchy sensation,redness,pain and tearing of the eyes.
Signs/symptoms Red…


RED EYES Red eye is a common sign seen in many eye conditions; most often people get eye drops from nearby pharmacies when these symptoms are seen.Self medication by patients often worsen their eye conditions due to wrong drug prescriptions acquired.the eye conditions sometimes report to doctors late resulting in majority of visual impairments.this article will give all patients an idea about common causes of red eyes,symptoms and plan if confused about actions needed if your eyes getred. Red eye is simply occurs when small blood vessels that are present on the surface of the eye(conjunctiva) becomes enlarged congested with blood.

This often happens when there an insufficient amount of oxygen supplyto the cornea,trauma,or an infection to eye tissues. Red eye normally is no cause for alarm but may be dangerous when it comes with signs and symptoms like: - Pain - Reduced vision - Abnormal discharge from the eye  - Difficulty looking at light - Problem with moving eye and headaches 
 RULE 1: SEE …