Saturday, February 9, 2008

7.19 Headaches

(Skrik, 1893, Edvard Munch - from headaches?)

Headaches are an interesting clinical entity. They are quite common yet with very few outward signs useful for diagnosis (except maybe temporal arteritis, see below). Plus the potential causative factors are many. Of course, we are talking real serious headaches, not those from muscular tension or sinus congestion; both of which most people are well aware of and who can often self-treat.

Most times, headaches can be diagnosed based on chief complaints, for example, in migraine and cluster headaches. One of the migraine prodromes, the occurrence of auras is quite well-known. [Note, however, in ocular migraines, auras do not lead to headaches.] And cluster headaches can last quite a few days; the patients often need to rest/recuperate in a dark and quiet place.

Patients with persistent headaches who show up in an eye doctor's office, are often referrals from the PCPs. The purpose is see if any of these apply: athenopia, angle-closure glaucoma, temporal arteritis, pseudotumor cerebri, pituitary tumor, etc. The PCPs may also plan, in addition to a complete physical to rule out hypertension, migraines, etc, neurological and radiological consults to ensure absence of space-occupying or vascular lesions, hemorrhages in the brain, or even meningitis. It is a multi-disciplinary process of elimination that can therefore be quite time-consuming.

From an eye doctor's perspective, any patients with headaches are suspected of having one of the following until proven otherwise:

Beyond the routine headaches checklist (throbbing/sharp/dull, where, when, how long, how bad, how treated), the first exam is to see if asthenopia is a contributing factor. Asthenopia is simply headaches caused by eye strain or uncorrected refractive error. The strain can occur when the eyes are forced to constantly re-focus, further worsened by insufficient accommodative reserve - typically in progressive hyperopia and/or incipient presbyopia, and much less well-known, in uncorrected astigmatism. The patient's complain of pain is usually vague; although it mostly refers to heaviness in and around the eyes. The symptoms disappear as soon as the refractive error is properly corrected. A good example is to switch from spherical equivalent to toric contact lenses for a full astigmatism correction. And the accommodative lag or insufficiency is remedied by applying more plus (or less minus) power. Asthenopia is, however, never truly debilitating, nor is it sight- or life-threatening.

Often the patient with acute angle-closure glaucoma attack ends up in the ER department of a hospital. Because the symptoms can include headaches, nausea, and vomiting. During attacks, the eyes show steamy corneas with limbal flush and often a distorted pupil as well (see image below):

As in acute angle-closure, patients with chronic narrow-angle glaucoma often complain of "brow aches". The cause is a true increase of pressure in the eye that can be readily measured with a tonometer. At the slit-lamp, gonioscopy is also performed to assess the angle - to see if the aqueous drainage is dangerously obstructed. Both hypotensive agents and laser iridotomy maybe needed to normalize the IOP to get to the origin of this type of headaches and prevent the visual field loss.

Temporal arteritis usually afflicts the elderly. It is a manifestation of a systemic giant cell arteritis that can sometimes lead to death. Usually the inflamed temporal artery can be seen snaking under the skin (shown in image below). The temple area is quite tender, certainly sensitive to touch, and painful while chewing. The blood supply to the optic nerve and the retina also can be compromised, causing irreversible loss of vision. Definitive diagnosis is based on erythrocyte sedimentation rate (ESR) and temporal artery biopsy. The treatment of choice is naturally the use of systemic steroids which can reduce the inflammation rather quickly.

Then we have the pseudotumor cerebri. As the name indicates, this is not a real tumor inside the cranium, but an increase in intracranial pressure owing to the presence of excess cerebrospinal fluid (CSF). Usually the patient is a slightly over-weight woman of child-bearing age. Birth control pills, vitamin A, and tetracyclines are all risk factors. Because of the increase in the intracranial pressure as in hypertension, sometimes papilledema is seen (shown below). Papilledema is a swelling of the optic disc, so the disc margin is now raised and the demarcation blurred. These can be seen very easily with a hand-held ophthalmoscope.

Definitive diagnosis is lumbar puncture together with neuro-imaging, the latter to rule out brain tumor. There are other visual disturbances such as blurred vision and diplopia. In fact, these visual symptoms are the reason why the patients are referred to the eye doctors in the first place.

Speaking of brain tumor, pituitary adenomas that impinge upon the optic chiasm can cause bilateral hemifield loss. Which can be picked up by performing simple confrontation visual field tests. Definitive diagnosis is brain MRI. The MR image below is a T1-weighted coronal scan showing a large hyperintense area (arrows), i.e., the pituitary tumor.

Headaches are of course a prominent feature of pituitary adenoma. They also can be the only manifest, and to the surprise of many eye doctors, without involving any visual field loss. Needless to say, pituitary tumors must be removed (usually through the nose to reach the base of the brain where the pituitary gland is).

Diagnosis and treatment of headaches can be exciting and rewarding - particularly if a potentially sight- and/or life-threatening lesion is the root cause. Fortunately, most cases are benign, stress-induced variety.

Wednesday, February 6, 2008

7.18 Nip and tuck


Cosmetic eye surgery has always been very popular. In Asia, for example, double-upper-lid surgery (see above) is a perennial ladies' favorite - for a more "spirited" look, allegedly. In the US, the low insurance reimbursement rates for other procedures have forced surgeons to seek additional sources of revenue. And medically unnecessary cosmetic surgery is paid out of pocket by the patients. It is therefore a perfect solution, especially if the surgical outcome meets the expectation of the patients. Botox injection to remove the wrinkles and thermo-lasers to re-surface the skin are now common place.

Medical necessity simply means whatever is "reasonable and necessary for the diagnosis or treatment of illness, injury, or to improve the function of a malformed body member" - according to Medicare. So the double-lid surgery cited above does not qualify. Also excluded is the "bags under the eyes" which are simply too common to merit any especial attention. They are essentially pockets of fatty tissues which can be removed and the skin tightened with the basic Z-plasty. Some of course opt for the procedure to look younger. Sometimes, however, the "bags" are from accumulation of fluids, as part of a general fluid retention, then the underlying problem(s) should be addressed instead.

There are many medically necessary cosmetic surgeries for the eye/orbit, usually performed by specially-trained hospital-based plastic surgeons. To name a few: ptosis repair, excision of cancer of the lid-margins, orbital decompression for Graves' Disease, patching of fractured orbital bones, prosthetics implants, reconstruction of facial deformity, repair of tear drainage system, and pterygium removal. This list probably should alert you that not all plastic surgeons are trained or qualified to operate on the eye and orbit.

A few examples of the eye plastics are presented below:

The most common procedure is probably that for repairing ptosis, i.e., drooping eyelids, that can interfere with vision.
In the case pictured above (notice also the bags under the eyes), clearly the visual field of the right eye is severely limited. The levator or Muller's muscle is therefore shortened to lift the upper lid. Ptosis can be bilateral. It can be congenital or acquired. The latter as a result of Cranial Nerve III palsy or myathenia gravis; both of which accompanied by double vision.

Very few people know how a prosthetic eye is fashioned. It actually requires the implant of a sphere made of porous polyethylene into the orbit to replace the enucleated eye - porous to allow migration of cells into it. Then the 4 straight rectus muscles are re-attached and the sphere covered with conjunctival tissue. After proper healing, an acrylic shell with the painted iris is then inserted (see image below).
The outcome is, without exception, quite striking. It is not uncommon for a novice eye doctor trying to examine the prosthetic eye, to the great bemusement of the patient.

Graves' disease, commonly known as hyperthyroidism, can cause enlargement of the extraocular muscles or increasing volume of the orbital fat (both within and without the EOM cone). This increase forces the eyeballs to bulge out - not only cosmetically undesirable but often the vision may be compromised. It is therefore necessary to decompress the orbit, by removing part of either the orbital bones or the fatty tissues, or both.

Very simplistically put, ocular/orbital plastics is practiced by very talented artists who happen to be skilled surgeons.

Tuesday, February 5, 2008

7.17 Wink, wink

("The Wink" - Seinfeld: Season 7, Episode 114, 12 Oct 1995)

The fans of the 1990s "a [TV] show about nothing" known as "Seinfeld" will readily recall "the Wink" episode. In which, a bit of grapefruit juice was accidentally squirted into George Costanza's left eye causing George to wink at inopportune moments.

First, a little info on first-aid: Any time when acid or alkali is splashed onto the eye, the most important first action is to rinse the open eye with copious amount of normal saline, or tap water if saline solution is not available. A few liter or more is generally needed. Then seek immediate medical attention so that the anterior structure of the eye can be preserved. Acid and alkali burns are different. Acid causes protein denaturation on contact. The denatured protein sometimes can form a barrier to prevent further acid erosion. On the other hand, alkali can penetrate deep into ocular tissues. Alkali burn is long-lasting and far more difficult to manage. In either case, saline/water rinsing is the crucial first step.

Back to "Seinfeld". The pH of grapefruit juice is around 3, mild in comparison to, e.g., HCl; although it does cause some discomfort for the eye. Tear fluid in the eye is poorly buffered yet its pH usually stays at a comfortable 7.4, until disturbed. George's winking or twitching, known as myokymia, is from acidic irritation to the nerve endings of the orbicularis oculi muscle in the lower eyelid (occasionally, the upper eyelid can be affected). Myokymia usually resolves itself. In very annoying cases, anti-histamine eyedrops can be used to slow down the muscle contraction. The best one Livostin unfortunately is no longer in production, probably lost out to Botox injection?

There is another uncontrollable winking, know as the Marcus-Gunn jaw-winking syndrome, in which the patient's eye (or eyes) twitches when chewing or suckling. In this case, there is a wiring problem: the eyelid levator muscle, instead of being innervated by a branch of Cranial Nerve III, is now by the motor branch of Cranial Nerve V. It can be regarded as a birth defect; although nothing untoward is involved.

More persistent and chronic twitching of the eyelids of both eyes is known as blepharospasm. It has been noted for years that blepharospasm seems to predate the onset of Parkinson's disease. Recent findings suggest that indeed if there is a lesion in substantia nigra, then Parkinson's eventually does develop. Others report that L-DOPA used to treat Parkinson's can cause blepharospasm. Sort of a lose-lose situation. Other possibilities include the usual suspects: fatigue, dry eye, stress, too much caffeine, etc.

Truly debilitating eye twitching involves half the face, i.e., hemifacial spasm or Meige's Syndrome, that can severely curtail both speech and eating. It is usually a result of inflammation of the facial nerve (Cranial Nerve VII), a sequela of Bell's palsy, or from a tumor or blood vessel pressing on the facial nerve. This can be treated with muscle relaxants, Botox injection, or neurosurgical repair.

Indeed, a wink is not quite just twitching of the eyelid.

Sunday, February 3, 2008

7.16 Organ donors

(A post-op transplanted cornea - the zig-zag lines are the sutures)

Organ donation remains a voluntary act, at least in the US. The way it must be. Usually, at driver's license renewal, a question on whether you are willing to donate your organs is put forth. You can answer either yes or no and your wish is honored. Or you can carry a donor card with you (see picture below). In the hospitals, it is often a difficult task for physicians to request organ donation of a deceased from the grieving family; although who almost always give their consents.
Organ donation actually cuts through social, cultural and religious boundaries. It is a universal human act of giving and care.

Donated organs that can benefit many others include: Kidneys, heart, liver, pancreas, intestines, lungs; skin; bone and bone marrow; and the cornea. To keep these organs/tissues safe, both the FDA and the Health Resources and Services Administration (part of the HHS) have issued rules and guidelines - necessary for avoiding life-threatening infectious agents. Unfortunately, there are also unscrupulous operators who provide contaminated or cancerous organs that result in the death/injury of the recipients.

Here, we will touch upon the corneal issue. You can elect to donate only your corneas (see donor card above). They are a true gift of sight. The Sri Lanka Eye Donation Society is known to have collected tens of thousands of corneas, made available not only to Sri Lankans but also to numerous patients in other countries. These and all other donors deserve our special gratitude and respect.

It is estimated that in the US, between 30-50,000 corneal transplants are performed each year. And the reason for such an operation is to restore vision to patients with the following problems:

Keratoconus (cone-shaped cornea, see illustration below) and thinning of the cornea
Cornea scarring and ulcers (caused by, e.g., infection or injury)
Corneal opacities or severe edema

(Keratoconus - from
Eye banks are now responsible for retrieving and preserving the donor eyes which are then provided to corneal surgeons. Since the eyes have limited "shelf life", unused (plus those deemed unsuitable) eyes can also be used for lab research. Essentially, there is no such thing as a wasted donor eye.

So can the donor corneas be preserved for as long as possible without losing their viability? In the olden days, the whole eyes were simply stored in a refrigerator and the corneas used within 2 days. Now, the excised corneas are placed in culture media such as Optisol GS or Eusol-C, which can preserve the cornea for up to 2 weeks (at 0-4°C). Other MEM-based modified culture media may also be used if needed. The corneas are inspected for the shape and count of the endothelial cells. The more cell loss the less viable/successful after transplantation.

Technically, there are three corneal transplant procedures. The most common is Penetrating Keratoplasty, in which the whole damaged cornea is replaced with the donor cornea. A trephine (similar to a miniature cookie cutter) is used to cut the donor and recipient corneal buttons, so the sizes match. Unexpectedly, the recent popularity of LASIK has actually reduced the donor cornea availability because the cornea now maybe too thin for penetrating keratoplasty. The alternative is to use only the endothelium, which is untouched by the LASIK procedure, for Deep Lamellar Transplant. Yet another procedure is the Surface Lamellar Transplant, in which, only the superficial layers of the cornea, in toto, are replaced. The corneal surgeon of course is the one who can decide which procedure works the best for you.

Corneal transplants have the usual surgical complications such as infection, bleeding, inflammation, and the occasional rejection (rare because the cornea is not a vascularized tissue). However, the success rate is quite high, e.g., 98% in keratoconus repair and more than 90% overall. We have just seen a case of of keratoconus that recurred after the transplant. This has been reported by others, in 11.7% of post-op cases. The causative factor is, however, still unknown.

By and large, corneal transplant, as cataract extraction, is a very safe way of replacing damaged corneas.