الفهرس 
Anatomy & Embryology & of the LensOnly 14 pages are availabe for public view
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Abstract
Most bilateral cataracts are due to inherited and/or systemic diseases, whereas unilateral cataracts are almost always caused by some local ocular phenomenona or developmental abnormality that involves other structures of the eye as well. However, after a thorough evaluation there is no discernible cause.
Leukocoria or white reflex can be the presenting sign of a cataract. In fact, there is no benefit in doing a large number of tests and investigations on all children with cataract. It is better to take a careful history, including a family history from the parents. Ask about any illnesses or drugs used during the pregnancy, and find out if the child is developing normally, the child preferred to be examined by pediatricians, who can look for other congenital anomalies, and can determine if the child is fit for general anesthesia.
The fundus should be assessed by indirect ophthalmoscope, looking particularly for underdevelopment or malformation of the disc or macula and the presence of abnormal pigmentation.
Deciding on the appropriate timing of surgery is most critical during early infancy. In the case of a unilateral dense cataract diagnosed at birth, the surgeon can wait until 4-6 weeks of age. Waiting until this age decreases anesthesia-related complications and facilitates the surgical procedure. Waiting beyond this time, however, adversely affects visual outcome.
More and more clinicians implant IOL every year. It results, first of all, from the improvement of surgical technique and preferences of parents for IOL implants versus correction with contact lens, facilitating later visual rehabilitation. Intraocular lens implantation is also associated with lower further costs.
It is well known that the majority of the eye’s axial growth occurs during the first 2 years of life. This rapid eye growth makes selection of an IOL power for an infant difficult.
Power calculation with different IOL formulas depends on axial length and corneal power. Axial length is changing from 17mm at birth to 23mm at the age 13 to 14 years. In the same time corneal power is decreasing from 53 D to 43 D. Most of this development occurs during first year of life. According to these changes also IOL power to be implanted in different age of children decreases from 32 D at the birth to 21 D at the age 13 to14 years.
Postoperative opacification of the posterior capsule is common in children. It is the most important complication of pediatric cataracts because even a technically successful surgery may eventually be functionally unsuccessful if the visual axis does not remain clear for long-term amblyopic therapy. Many authors advocate a planned primary posterior capsular opening at the time of initial cataract surgery for all children less than 6 years of age.
Primary posterior capsulotomy and anterior vitrectomy is regarded nowadays as standard surgical procedure of pediatric cataract surgery in young children.
Nd: YAG laser can also be used to perform posterior capsulotomy, when VAO is not dense and the child can cooperate for YAG laser capsulotomy. However, reopacification of YAG-laser openings have been reported in pediatric eyes.
The best outcomes after surgery depend on several variables. This includes the extent of cataract, associated ocular or systemic abnormalities, early diagnosis and removal of cataract, optimal optical correction, and aggressive visual rehabilitation for several years.