A Christmas tree in the eye

Medicine never ceases to amaze.  I just read a case report published in the BMJ by Ebube E Obi and C Weir about a Christmas tree cataract. I have seen some cases of cataract but I have not seen a Christmas tree cataract. May be sometime in future I will.

They report a case of a 73 year old woman who presented with a Christmas tree cataract of the left eye. The Christmas tree cataract was highly reflective, iridescent and polychromatic. They look like little needles in the eye going in all directions and assume the shape of a Christmas tree. The needles change color when the angle of the incident light is changed. The woman was referred to them for cataract surgery.

A Christmas tree cataract. From BMJ. 

Any opacity in the lens of the eye is called a cataract. Senile cataract is the commonest type though there are many other types. Usually it is accompanied by progressive impairment of vision but in Christmas tree cataract the vision may be 6/6 which is normal. In a Christmas tree cataract, the adjacent areas of the lens remain clear.

GA Shun-Shin et al. had examined the morphological and chemical composition of Christmas tree cataracts. They had examined four Christmas tree cataracts that were extracted and eight Christmas tree cataracts from donor eyes by scanning and transmission electron microscopy. Chemical composition was analyzed by energy dispersive x-ray microanalysis and Raman microspectroscopy.

Electron microscopy showed that Christmas tree cataracts were made up of rectilinear crystal like structures traversing the eye in all directions. The crystalline structures consisted of varying number of plate like elements stacked up together having a periodicity of about 5 nm. It has been suggested that the origin of these structures lie in the reticular meshwork. With increasing age there is degradation of the peptides and amino acids within the lens by endopeptidases. There is an increase in calcium ions and this local increase in calcium ions stimulates the endopeptidases resulting in protein breakdown. The breakdown products are subsequently deposited in the lumen of the reticular meshwork forming the Christmas tree cataract. Radiographic microanalysis showed the presence of sulfur in the crystals of the Christmas tree cataract. Raman microspectroanalysis showed increased CS-SC and S-S vibrations. The crystals are thus taken to be made of cystine (an amino acid). Accumulation of cystine beyond the point of crystallization causes the formation of needles that gives the fascinating appearance of the Christmas tree in the eye.

Reference:

Obi, E., & Weir, C. (2010). A Christmas tree cataract BMJ, 341 (dec08 3) DOI: 10.1136/bmj.c6644


Shun-Shin GA, Vrensen GF, Brown NP, Willekens B, Smeets MH, & Bron AJ (1993). Morphologic characteristics and chemical composition of Christmas tree cataract. Investigative ophthalmology & visual science, 34 (13), 3489-96 PMID: 8258504

Going for fishing: What’s the catch?

It is very unfortunate to have a leisurely activity end in a disaster. A recent case report by Inchingolo F et al. published in the Head and Face Medicine journal illustrates this. When you go for fishing, you may end up with more than what you would have bargained for; the catch may be your very own eye, or in this case, the eyelid.

The authors describe a case of a young 32 year old male fisherman in whom the fish-hook he was using got embedded in his right eyelid. When he was reeling the hook back, it hit him in the face and attached to his right eyelid. He was fortunate that the eye was not injured. The hook was removed under local anesthesia by making a small incision and the patient made a full recovery. He even wanted to resume fishing.

Fish-hook injury to the eyelid. From Head and face medicine.

Fish-hook injuries to the eye would be considered as penetrating injuries to the eye. If you look at the figure, the ends of the fish-hook are curve backwards with a barb. Now I am no expert on fish-hooks, but I would guess they are designed to keep the fish hooked, the more the fish struggles to get it off, the more deeply it attaches. Same thing happens in case of an accidental injury. If you try to get it off forcibly, it will cause even more damage.

Penetrating injuries of the eye are potentially dangerous and they should receive prompt treatment. They are dangerous due to –

• Immediate effect of the trauma.
• Infections may be introduced.
• Sympathetic ophthalmitis.

Layers of the eye. From Patient UK.

Immediate effects of trauma may be on the lid and conjunctiva and they are common as they serve to protect the eye. In lid injury, the site of the injury must be stitched meticulously. Even then, there may notching of the eyelid upon healing, but it was not there in this case. The cornea may also be injured, having a linear wound or a lacerated wound. The corneal endothelium swells up as a result of the injury and the cornea becomes cloudy. In case of large injuries to the cornea, there may be prolapse of the iris and it becomes adherent to the cornea upon recovery. The eyeball itself may rupture in severe cases. The lens may also be involved in the injury. In minor injuries to the lens, a traumatic cataract is formed with subsequent loss of vision. This is treated by removing the cataract. In severe injury to the lens, there is a large wound at the anterior capsule of the lens and the cortical matter of the lens comes out in the anterior chamber as white floccules.

The fish-hook can also cause infection of the eye. Purulent keratitis, that is, pus forming corneal inflammation can occur. This can give rise to frank purulent corneal ulcer which forms a corneal opacity on healing and impairs vision. Endophthalmitis, inflammation of the inner coats of the eyeball and panophthalmitis, inflammation of all the layers of the eyeball can also occur. Panophthalmitis is a dangerous condition with poor prognosis and the eye may have to be removed.

Another dangerous condition that may occur is sympathetic ophthalmitis. In sympathetic ophthalmitis, the uninjured normal eye also becomes involved in inflammation, in addition to the injured eye. Vision becomes impaired in both the eyes. It is thought to be autoimmune in origin, in which antibodies produced against the uveal pigments, uveal proteins and retinal proteins of the injured eye attack the normal eye.

How can fish-hook injuries be prevented? Simple precautions will suffice. Protective goggles will suffice in protecting the eye. Caution while handling the hooks will also be protective.

Reference :

Inchingolo F, Tatullo M, Abenavoli FM, Inchingolo AD, Inchingolo AM, & Dipalma G (2010). Fish-hook injuries: a risk for fishermen. Head & face medicine, 6 (1) PMID: 21156039