- Deliberate متعمد
- Overdose as self-harm or suicide attempt.إنتحار
- Child abuse .
- Munchhausen's syndrome :Factitious disorder, Hospital addiction syndrome(e.g psychic patient).
- Third party (attempted homicide, terrorist, warfare).
- Accidental عن غير قصد
- Most episodes of paediatric poisoning.
- Dosage error.
- Iatrogenic
- Patient error
- Recreational use.
- Environmental:
- Plants
- Food
- Venomous stings/bites.
- Industrial exposures.
Friday, November 28, 2008
- Types of Poisoning.
Thursday, November 20, 2008
- cornea.
* Definition :
It is a colorless (transparent) structure
covering the anterior 1/6 of the eye ball.
*Development of the cornea:
- Surface ectoderm forms the epithelium of the cornea.
- Mesoderm gives rise to the corneal stroma.
- Neural crest cells gives rise to the corneal Endothelium.
**Characters of the cornea :-
- colorless (transparent) structure and has a smooth surface.
- A vascular structure.
- Highly innervated by non-myelinated trigeminal nerve fibers.
-The most powerful refractive media of the eye
( 42+ diopters ).
- Diameter :-
- Horizontal = 12mm
- vertical = 11mm Why…?
& lower sides of the cornea.
- It is not uniformly curved How…?
>>the central or optical zone having a smaller radius of
curvature than the peripheral parts,and the
posterior surface is more strongly curved than the anterior.
>> Ant radius of curvature = 7.7 mm
>> Post radius of curvature = 6.6 mm
>>Thus the cornea is thinner (0.6 mm) at its
center than near its margin (1 mm).
Dr Ibrahim
Wednesday, November 19, 2008
- gonioscopy.
In the name of Allah
to know the principle of goniolens we
must know some important information.....
- corneal R.I = 1.38
- Air R.I = 1.00
- Goniolens eliminates the total internal reflection by replacing the cornea-air interface by a new geniolens-air interface that has higher R.I (n=1.50) than
that of the cornea and the tear.
-uses :-
used for viewing the anterior chamber angle of the eye for evaluation, management and classification of normal and abnormal angle structures which is important in glaucoma management and evaluation.
- Contraindications for gonioscopy:-
- Hyphaema.
- Compromised cornea (e.g corneal ulcer).
- Lacerated or perforated globe.
Thanks alot
Dr Ibrahim
Saturday, November 15, 2008
- Anatomy and histology of eye lids.
- Eye lid :
- It is movable muco-cutaneous fold covering anterior surface of eye globe.
- Upper eye lid is more movable than lower eye lid as it have levator palpebrae superioris muscle and Muller's muscle .
- The upper eyelid skin crease (superior palpebral furrow) is approximately 8-11 mm superior to the eyelid margin and is formed by the attachment of the superficial insertion of levator aponeurotic fibers (8-9 mm in men and 9-11 mm in women).
Sunday, November 9, 2008
- Development of eye lids.
Begins during 6th week.
process:
1- Eye lids develop from two folds of skins over the
cornea during 6th week.
2- Eye lids adhere to each other by the beginning of 10th week
& remain adhered till 26th to 28th weeks.
Congenital anomalies:
usually congenital anomalies appear together
to give a syndrome.
1-congenital ptosis:-
cause: failure of development of levator palpebrea
superioris muscle.
- It may be simple( alone).
- It may be associated eith other lid deformities or
congenital opthalmoplegia.
- it is usually bilateral & hereditary.
2- Epicanthus:
- is a semilunar skin fold at the side of the nose
covering the medial canthus & the caruncle leading
to false convergent squint.
3- Telecanthus:
increased distance () two medial canthi.
4-Blepharo-phimosis: -Diminution of the horizontal width of the palpebral fissure from 25-30 mm (normal) to 18-22mm without pathologic changes in the eyelids. - It is rare & usually asscociated in Blepharo-phimosis syndrome. 5-Blepharo-phimosis syndrome: presence of congenital ptosis,Epicanthus, elecanthus & Blepharo-phimosis with each other.
6- Congenital trichiasis ( distichiasis)
- rare condition.
- In which abnormal extra raw of lashes replacing white line.
7- Congenital entropion:
- rare with micropthalmos.
8- Congenital ectropion:
- rare with Blepharo-phimosis syndrome.
9- coloboma of the eye lids:
- It is triangular , quadrilateral or
irregular shaped defect of the lid margin.
10- Epiblepharon:
-horizontal redundant medial fold of skin of the
eye lid inducing vertical orientation of the cilia.
-Epiblepharon may co exist with entropion.
-It usually imrpoves by age as the eyelid skin stretches.