Focus on amblyopia, thyroid eye disease and papilledema

Neuro-optometry is a rapidly expanding field, with more and more optometrists becoming more involved in the diagnosis and management of certain serious and common neurological diseases. Pilar Vergara, DOO, FCOVD, who practices in Albacete, Spain, Richard Castillo, OD, DO, of Tahlequah, OK, and Kelsey Moody Mileski, OD, FAAO, of Marietta Eye Clinic, Marietta, GA, provided their take on these diseases.

Amblyopia: a paradigm shift

Pilar Vergara, DOO, FCOVD, described a new treatment paradigm for the management of anisometropic amblyopia. She and her colleague Robert Sanet, OD, developed a new protocol to circumvent the shortcomings of the current standard treatment, i.e. the patch.

These disadvantages include resistance to wearing the patch, difficulty in school and play due to the need to use the amblyopic eye to process information and perform, disappointing results with long treatment, effects long-term psychological effects on children and parents resulting from the patch and difficulties achieving 20/20 vision and maximum stereopsis, Dr. Vergara said.

Unlike the old treatment protocol, which states that the primary problem is reduced visual acuity, the patch is the optimal treatment, and the optimal prescription is based on greatest to best visual acuity, Drs. Sanet and Vergara proposed a new neuroscience-based treatment for amblyopia.

And, indeed, they believe that reduced vision is not the problem but only a symptom of the underlying binocular problem.

This thinking represents a paradigm shift.

They described their keys to success as follows: the timing and sequence of each step is crucial; the prescription of lenses is based on obtaining maximum binocularity and not maximum visual acuity; unequal additions are frequently prescribed; monocular fixation in a binocular field; optometric phototherapy; use of graduated occlusion; and optometric vision therapy.

In less complicated cases, i.e. defined as best corrected visual acuity (BCVA) of 20/50 or better and anisometropia less than 6 diopters (D), using the new protocol, 80% of patients can achieve 20/20 vision and 20 arc seconds of stereopsis without the need for a patch over 12 to 15 weeks.

In more complicated cases, defined as 20/50 to 20/200 BCVA and anisometropia up to 8 D or greater, most patients can achieve 20/20 to 20/25 vision and 20 to 30 seconds of stereopsis without any patch within a maximum period of 24 weeks.

Drs. Sanet and Vergara can explain the neuroscience research behind their new model and the steps needed to achieve better clinical outcomes. They have designed 2 courses that are currently available: a new amblyopia treatment paradigm and tearless amblyopia treatment – faster and better results without a patch.

Thyroid eye disease (TED): it takes a whole village

Dr. Castillo described current knowledge of PDD, which most commonly manifests as Graves’ disease (hyperthyroidism, however, can also develop in hypothyroid and euthyroid patients (normal hormone levels). The disease is complex and patients can benefit from the expertise of a number of specialists and sub-specialists.

The complexity of this disease is highlighted by the many attempts to classify its many manifestations. There are currently no less than 5 classification schemes. Type I includes cases with minimal inflammation and restrictive myopathy, and type II moderate to severe inflammation and restrictive myopathy.

NO-SPECS includes 7 classes of PDD ranging from Class 0 with no signs of symptoms to Class 6 with vision loss and optic nerve involvement.

The VISA classification, i.e. vision, inflammation, strabismus and appearance, defines vision, inflammation and congestion based on documented changes in inflammation rather than absolute value , strabismus and motility with measured ductions and alignments, and appearance and exposure. A score of 5 or greater when using this classification indicates active disease or progression for which steroids should be considered.

The EUGODO classification defines mild disease as swelling and retraction of the eyelids and proptosis; moderate to severe disease as active disease that includes diplopia, proptosis greater than 25 mm, and extraocular muscle dysfunction.

The classic clinical features of thyroid (Grave’s variant or hyperthyroid) eye disease include goiter, proptosis, and pretibial myxoedema, Dr. Castillo explained.

Risk factors for developing ocular manifestations include age at onset, duration of hyperthyroidism, and smoking. These manifestations include eyelid retraction/proptosis, conjunctival chemosis/hyperemia, periorbital edema, diplopia, keratitis/exposure keratopathy, and optic neuropathy compression.

Examination may reveal eyelid signs that include fixed appearance, eyelid shift on downward gaze, eyelid retraction, incomplete and infrequent blinking, lower eyelid edema, and eyelid shift lower on upward gaze.

The standard screening tests for Graves’ disease are thyroid-stimulating hormone and free T4. Conventional treatments include beta-blockers, thioamide, radioactive iodine ablation; surgical approaches are thyroidectomy and TED-specific surgeries, ie orbital decompression, strabismus, eyelid lengthening, blepharoplasty; and more recently teprotumumab infusion (Tepezza, Horizon Therapeutics).

Clinicians involved in treatment include endocrinologists or internists, oculoplastic surgeons, strabismus surgeons, and neuro-ophthalmologists.

“Thyroid eye disease, whether due to the hyperthyroid, hypothyroid, or euthyroid state, can be considered an immunological derangement, and understanding the immunopathology involved helps explain the ocular manifestations of PDD,” said the Dr. Castillo.

Papilloedema vs pseudopapillary edema: differentiating the two

Papilledema is a medical emergency and patients should be referred to the emergency room, according to Dr. Mileski.

The disease is characterized by swelling of the optic disc secondary to elevated intracranial pressure (ICP) which is bilateral in most cases. Elevated ICP causes headache, nausea, vomiting, diplopia, pulsatile tinnitus, and transient visual obscuration.

Papilledema can result from the presence of an intracranial mass, cerebral hemorrhage, meningitis, hydrocephalus, spinal cord injury, venous drainage obstruction, and hypertension idiopathic intracranial (IIH). The presentations of these are similar, but all should be excluded from the differential diagnosis before IIH is diagnosed, she advised.

Patients with IIH have normal vision and color vision, possibly diplopia, enlarged blind spot, and elevated retinal nerve fiber layer and neuroretinal rim on optical coherence tomography (OCT) of the optic nerve. On dilated examination, the optic nerve appears raised and swollen. Darkening of the vessels, Paton’s lines and hemorrhages may be present.

In contrast, pseudopapillary edema is characterized by the absence of an optic disc cup, small disc, vascular trifurcation, drusen, and spontaneous venous pulsation.

OCT can be useful in differentiating between the two diseases by visualizing drusen and peripapillary wrinkles. Fundus autofluorescence (FAF) may also show buried optic disc drusen.

However, the future is bright for diagnosing both conditions through the use of deep learning systems.

The treatment of papilledema depends on its etiology, i.e. a mass or Chiari malformation is treated surgically, cerebral vein thrombosis by treating the underlying cause with anticoagulants, and IIH with diet, weight loss and pharmacological or surgical treatment.

A new observation about papilledema resulting from IIH is that findings suggestive of IIH on magnetic resonance imaging (MRI) may be the same as in those without IIH. Another new observation is that the prevalence rate of papilledema increased from 2.8% in patients with at least 1 sign on MRI to up to 40% when more signs of IIH were present at imagery.[MK1] . Despite the MRI results, the only way to truly diagnose IIH is through a lumbar puncture.

It is also important to remember that anemia can make IIH papilledema worse. In addition to changing diet and weight loss, the underlying anemia must also be treated. The typical treatment for papilledema is acetazolamide (500 mg twice daily and titrated up to 2 grams daily). Once the papilledema has improved, this dosage can be reduced. Optic nerve sheath fenestration may be reserved for severe cases of vision loss.

Dr. Mileski’s clinical pearls include the following:

  • Papilledema is a medical emergency
  • Symptoms, clinical examinations, OCT, and visual fields should all be used to differentiate papilledema from pseudopapillary edema

• Physicians should perform an urgent outpatient workup in case of uncertainty.

• Artificial intelligence could be useful in the future.

  • IIH is a diagnosis that requires normal MRI, magnetic resonance venography and lumbar puncture
  • IIH without papilledema is possible but rare
  • Patients with IIH should be asked about anemia

“Clinical tools can help differentiate papilledema from pseudopapilledema. If papilledema is suspected, these patients should be referred to the emergency department for appropriate diagnosis and treatment. Patients should have normal neuroimaging ( MRI, MRV) and high burst pressure for a diagnosis of IIH. These patients should also be tested for anemia as this can worsen their condition,” Dr. Mileski said.

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