Traumatic injuries to the eye are common, and can result in significant vision loss or even blindness if not managed properly. Chemical injuries to the eye can also cause severe damage if not treated promptly.
Therefore, mechanical trauma and chemical injuries of the eye are important topics in ophthalmology, and are likely to be tested in the NEET PG exam to assess your understanding of these important clinical scenarios.
Read this blog further and get a quick overview of this important ophthalmology topic.
M/C wall of orbit to fracture in blow out fracture: Inferior wall /floor
Thinnest wall : Medial wall
Fracture of medial wall prevented by ethmoid air cells
Easy to fracture inferior wall as it rests on cavernous maxillary sinus with no air cells
Tear drop sign in seen
M/C site of scleral rupture - Limbus & just under the insertion of rectus muscles (thinnest past) → Seidel’s test
M/C site of lodgement of foreign body: under the upper eyelid, in the palpebral conjunctiva.
Corneal penetration / perforation
Black Ball / Eight ball hyphema- total hyphema - optic atrophy if IOP > 50 mmHg for 5 days
Eight ball hyphema: Traumatic hyphema
Grade 0: Microscopic hyphema not seen under slit lamp examination
Grade 1 : 1/3rd of AC depth filled
Grade 2 : 1/3rd – ½ AC volume filled
Grade 3 : > half till almost entire chamber
Grade 4 : Entire AC chamber
M/C type of traumatic glaucoma: Angle recession glaucoma, gonioscopy essential for diagnosis
D shaped pupil seen in Iridodialysis
Ciliary body injury has max incidence of sympathetic ophthalmitis
Rosette cataract & Vossius ring on lens
Imprint of pupil on anti-lens capsule
Usually smaller than pupil because pupil constrict at time of impact.
Vitreous base avulsion - sign of trauma ; vitreous avulsion occurs only due to trauma
Vitreous haemorrhage usually seen in young males on getting hit (like in Boxers)
Berlin's edema : Post traumatic macular edema ( cherry red spot ) ; a/k/a commotio retinae
Traumatic optic neuropathy : Occurs when injury is close to eyebrows
Optic nerve avulsion: Leads to injury to optic canal & optic nerve
It is simultaneously injury + rotation of eyeball
CHEMICAL INJURIES OF EYE
Treat first ask questions later
Alkaline injury more dangerous than acids
Alkaline can penetrate more and damage, acids usually precipitates
Most domestic solutions are alkaline
Most common acid causing chemical injury to eye is Sulphuric acid
Most dangerous acid Hydrofluoric acid
Most common alkali is Calcium hydroxide (lime)
Most dangerous alkali is Ammonia
Factors of prognosis
Duration of contact
Limbal area of damage
Dua classification is used for chemical injuries of eye
Irrigation with BSS (Balanced Salt Solution): 1/2 L over 30 min through IV tube
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