Photophobia- eye’s disorder.

Photophobia
Name
Institution

Photophobia
Introduction
Photophobia is a debilitating medical condition that primarily affects the eye to introducing light sensitivity, although that is just a functional symptom that does not have a specific organ basis. It is presented as an abnormal eye sensitivity or aversion to light, explaining its nomenclature: ‘photo’ the Greek word for light and ‘phobia’ Greek word for fear. Individuals suffering from the condition complain of exacerbated eye discomfort or even pain when exposed to increasing light that should otherwise not have been uncomfortable (Muchnick, 2008). It is a common primary complication arising from eye conditions that include retinal dystrophies and uveitis. In fact, it is reported in neuro-ophthalmic disorders and migraines. The International Classification of Headache Disorders reports that photophobia is a classic indication of a migraine. In addition, its presence is considered as an indication of blepharospasm, traumatic brain injury, intracranial conditions, posterior segment disease, anterior segment disease, progressive supranuclear palsy, and so on. As such, photophobia can be considered as a debilitating indication of neurologic and ophthalmic medical disorders (Ashley, 2010; Brodsky, 2010). Therefore, photophobia can be considered as a sensory state in which the eyes feel uncomfortable owing to light sensitivity even in light conditions that are normally comfortable.
Causes
As earlier indicated, photophobia is a complication arising from a range of medical conditions that affect the eye and brain.

Firstly, anterior segment diseases (such as blepharitis, cyclitis, and iritis) have been reported to cause photophobia. This is because the disease is caused by the trigeminal afferents being irritated to cause eye and corneal innervation to result finally in superficial corneal lesions. The lesions cause the eyes to dry up causing corneal neuropathy that presents photophobia. Secondly, posterior segment disease (such cone dystrophies, retinal dystrophies, pigmentosa, and retinitis) cause photophobia when they present photopsia and hemeralopia. Thirdly, intracranial conditions (such as apoplexy, pituitary tumors, sub-arachnoid hemorrhage, and meningitis) cause photophobia by affecting the trigeminal nerve to innerve and irritate the meninges particularly in the regions around the diaphragma sellae. Fourthly, migraines cause photophobia as one of the intrinsic symptoms, to be accompanied by nausea and disability. This association is thought to be the result of the visual pathway dysfunction between the occipital lobes and retina that develops into light sensitivity. Fifthly, traumatic brain injury causes photophobia bringing about the injury, irritation or even displacement of the pain-sensitive intracranial structures thereby causing the eyes to be light sensitive. Finally, blepharospasm (presented as focal dystonia linked to closure, squeezing and blinking of the eyelids) causes photophobia by inhibiting and exciting the blink reflex from the brainstem (Wong & Liew, 2011).
In addition, photophobia has been linked to the occurrence of psychiatric conditions such as seasonal depression, bipolar depression, neurasthenia, and agoraphobia. This is because the eyes exposure to light has been noted to trigger anxiety attacks, with darkness noted to bring about a feeling of relaxation. In fact, the cognitive behavioral therapies for these psychiatric conditions have been noted to include light control as a principal feature (Manu & Karlin-Zysman, 2015). As a result, photophobia is reportedly caused by psychiatric conditions.
Effects on eye and body
Photophobia has been inextricably linked to increased light sensitivity and pain presentation in the head, and the eye in particular. This is because it affects the primary pain mediator (trigeminal nerve) in the brain thereby bringing about a sensation of pain to the head. In such cases, any light source results in discomfort. This forces the individual to close the eyelids or squint to reduce the amount of light entering the eyes. Nausea and headache could also result. These effects worsen with an increase in the amount of light. In addition, there is greater blink reflex and squinting in a bid to cut back the light glare and reduce the irritation (Ashley, 2010; Brodsky, 2010). Therefore, photophobia is associated with greater incidence of light sensitivity in the eyes and a sensation of pain in the head.
Test and diagnosis
Testing and diagnosis of photophobia involves a multistep process, which considers the patient’s medical history along with an examination of the neuro-ophthalmic and neurologic fields. These tests can be simplified as examinations of the visual field. Firstly, the medical history is collected in which evidence of prior central processing difficulties are presented. A positive history of central process difficulties will be accompanied by lumbar puncture, neuroimaging, and laboratory studies to ascertain current difficulties in central processing. The diagnosis proceeds to the second test if there is no history of central processing difficulties. The second test involves determining the presence of dry eyes. This is accompanied by Shirmer test, corneal staining, uveitis, and iritis. The presence of anterior segment disease and dry disease is addressed through treatment with anti-inflammatory medicine, artificial tears, ointments, and lid hygiene. The diagnosis proceeds to the third test if there is no uveitis, iritis, and dry eyes. The third test involves the determination of whether the photophobia is resolved by either dilation or topical anesthetic. If it is resolved, then further tests are conducted to ascertain the presence of dry eyes, uveitis, cyclitic, iritis, and corneal neuropathy. The diagnosis proceeds to the fourth test if the photophobia is not resolved by dilation and topical anesthetic. The fourth test involves checking for a family history of decreased visual acuity, nyctalopia, and hemeralopia. The presence of these conditions will indicate retinal dystrophy in which genetic testing, electrophysiological studies, and family history checks are conducted. If there is no family history of decreased visual acuity, nyctalopia, and hemeralopia, then the tests proceed to the fifth stage. The fifth stage involves checking for evidence of involuntary closure of the eye to light and excessive blinking. A positive result is considered as presence of blepharospasm and treated using surgical myectomy, medication, and botulinum toxin. A negative result will cause a migraine history to be taken, in which case incidences of vomiting, nausea, phonophobia, and eye pain are noted. A positive result is considered as presence of a migraine, in which case additional tests for depression and anxiety are conducted. A negative result will cause the whole process to begin with step one (Kahan, Miller & Smith, 2009; Collins, 2013). The six-step approach represents a typical test and diagnosis plan for photophobia.
Treatments, medications, surgeries
Although there are not definite treatments for photophobia, clinicians can apply a range of approaches to managing and treat the condition. Firstly, dark tinted lenses are used to decrease the dark-adapted state. Still, the dark tinted glasses have been criticized for increasing the pain and perception associated with light sensitivity. Red optically tinted glasses have also been used to manage photophobia, although they have been criticized for exacerbating migraines associated with the photophobia. FL-41 rose-colored tints have been noted to be more successful in managing the condition without presenting increased light sensitivity and migraine complications. This is because FL-41 tints are noted to block the blue-green light wavelengths that have been noted to cause the most pain and irritation in individuals suffering from photophobia. Secondly, the dry eyes can be treated with ointments, drops, and punctual plugs to increase lubrication. Thirdly, dilating drops such as cycloplegics can be used to provide relief from ocular inflammation since the medication reduces spasms of the ciliary muscle to reduce papillary dilation and decrease the amount of light entering the eyes (Prahlow & Kincaid, 2013; Suter & Harvey, 2011; Thurtell, Tomsak & Daroff, 2011).
Fourthly, systemic medication such as sedatives, anticonvulsants, calcium channel blockers, beta-blockers, migraine-specific medication, antidepressants, botulinum toxin, and topical lacosamide. Sedatives decrease trigeminal irritability by facilitating eye closure and increased sleep. Migraine-specific medication treats an acute migraine to reduce the photophobia that develops to accompany migraines. Antidepressants and anxiolytics act to reduce depression, panic, and anxiety disorders associated with photophobia. Botulinum toxin is used to treat blepharospasm. Systemic anticonvulsants (such as carbamazepine, pregabalin, and gabapentin) and lacosamide are used to treat corneal neuropathy. Seventhly, surgical procedures can be used to manage photophobia. This will involve injecting the supraorbital nerve to reduce the eye’s sensitivity to light. In addition, 50% alcohol can be injected into the orbit to cause ocular inflammation that alleviates photophobia. Besides that, lidocaine can be used to reduce the eye’s sensitivity to light by blockading the superior cervical nerve and other sympathetic nerves (Prahlow & Kincaid, 2014; Thurtell, Tomsak & Daroff, 2012).
Is there cured?
There is no cure for photophobia, rather the causal medical conditions can be managed to reduce its incidence, effect and severity to allow patients to lead near normal lives (Prahlow & Kincaid, 2014; Thurtell, Tomsak & Daroff, 2012).
Technological advances
There have been marked technological advances in the treatment and management of photophobia, except for the presentation of FL-41 tinted glasses. FL-41 tints are specially designed glasses that have a pinking look and block both the blue and green light wavelengths from passing through. These glasses are noted to reduce eyelid contraction and blink rate in individuals suffering from photophobia, thereby presenting a cheap and non-invasive method of managing the condition (Blackburn et al., 2009).
Overview of photophobia
One must accept that photophobia is a debilitating medical condition presented by the eye being sensitive to light and could be accompanied by pain sensation in both the eye and head. In addition, one must acknowledge that the presentation of photophobia is an indication of other medical conditions since it is a functional symptom of retinal dystrophies, uveitis, neuro-ophthalmic disorders, and migraines. As such, photophobia is caused by medical conditions affecting trigeminal nerve in the brain and eye, increasing its sensitivity to the slightest stimulation. The diagnosis of the condition will involve checking for the underlying causes and treating them as their presence is confirmed. This will include taking a medical history of the patient’s central processing, checking for dry eyes, taking a history of visual acuity, nyctalopia, and hemeralopia, checks for blepharospasm, and checking for migraines. Each condition is treated as its presence is confirmed that clearing them will alleviate the photophobia. Still, it is important for patients to know that the condition cannot be cured; rather it can only be managed by treating the causative medical conditions.

References
Ashley, M. (2010). Traumatic Brain Injury: Rehabilitation, Treatment, and Case Management, 3rd ed. Boca Raton, FL: CRC Press.
Blackburn, M., Lamb, R., Digre, K., Smith, G., Warner, J. … & Katz, B. (2009). FL-41 Tint Improves Blink Frequency, Light Sensitivity, and Functional Limitations in Patients with Benign Essential Blepharospasm. Ophthalmology, 116(5), 997-1001.
Brodsky, M. (2010). Pediatric Neuro-Ophthalmology, 2nd ed. New York: Springer.
Collins, D. (2013). Algorithmic Diagnosis of Symptoms and Signs: A cost-effective approach, 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins.
Kahan, S., Miller, R. & Smith, E. (2009). Signs and Symptoms, 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins.
Muchnick, B. (2008). Clinical Medicine in Optometric Practice. St. Louis, MO: Mosby Elsevier.
Manu, P. & Karlin-Zysman, C. (2015). Handbook of Medicine in Psychiatry, 2nd ed. Arlington, VA: American Psychiatric Publishing.
Prahlow, N. & Kincaid, J. (2014). Neuromuscular. New York: Demos Medical Publishing.
Thurtell, M., Tomsak, R. & Daroff, R. (2012). Neuro-Ophthalmology. Oxford: Oxford University Press.
Wong, T. & Liew, G. (2011). The Ophthalmology Examinations Review, 2nd ed. Singapore: World Scientific Publishing Co. Pte. Ltd.