Infections of the superficial skin around the eyes are called periorbital, or preseptal, cellulitis. It is predominantly a paediatric disease. Erysipelas is a bacterial skin infection involving the upper dermis which extends into the superficial cutaneous lymphatics. Sinusitis is in sinuses. Orbital infections and conjunctivitis are within the eye.

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disease. The Lisch nodule represents one of the most common NF1 ocular manifestations.NF1 is caused by a genetic mutation which can cause tumours to grow on nerve endings| these cutaneous neurofibromas are benign tumours which grow on the skin, often first appearing during the hormonal changes that occur in teenage years. They vary in size and can appear anywhere on the body. The number of neurofibromas present differs greatly between individuals and over a lifetime Café au lait spots (coffee coloured birthmarks) are often the first and most common sign of NF1, and these are often found at birth and are usually evident by 2 years of age.Other features of NF1 can include Lisch nodules of the iris (small pigmentation in the iris which causes no disturbance to vision), skin-fold freckling (freckling/pigmentation in the groyne and armpits), plexiform neurofibromas (or sub cutaneous neurofibromas) which are diffuse tumours that grow along a nerve and are found in at least 25 % of people with NF1, optic gliomas (tumour of the optic nerve), and skeletal complications including pseudarthrosis and scoliosis. Macrocephaly (large head size) is also common, and short stature is found in around a third of people with NF1. Rare complications include a risk of malignancy, organs being compromised by neurofibromas, seizures, and hypertension.

The most obvious sign of a congenital cataract in a child less than 1 year would be a strabismus/squint. A 12 month old child is unable to complain of loss of visual acuity and the child is likely to see well in one eye ruling out clumsiness. Amblyopia may also be difficult to test at this age unless it presents with the strabismus. ‘White’ red reflexes usually only present in very mature congenital cataracts.

From the given scenario, the extraocular muscle affected in the child is superior oblique muscle. Point to remember:All of the extraocular muscles are supplied by the oculomotor nerve (3rd cranial nerve), except superior oblique (trochlear nerve/4th cranial nerve) and lateral rectus (abducens nerve/6th cranial nerve).The superior oblique muscle causes the eye to move downwards and medially. The unopposed inferior oblique, in this case, causes the eye to deviate upwards and medially. Children tend to tilt their head (torticollis) to the side opposite to the affected eye with their chin down toward the shoulder, and their face turned away from the affected side to decrease the diplopia.

The most appropriate management would be to reassure the parents, as nasolacrimal duct dysfunction in most infants tends to resolve spontaneously.Note:Nasolacrimal duct blockage occurs in up to 5% of new-borns. 90% of these babies spontaneously resolve in the first year of life. They do not require urgent ophthalmological review, as often advice and reassurance for parents suffice for up to the age of 18 months old or so. A lump can often be seen in the nasolacrimal region following the accumulation of mucous. This does not need to be treated with antibiotics unless there are signs of acute infection.Other options:- The child does not require urgent ophthalmology review as there are no signs of severe infection. Watery eyes often lead to mucous production, which is a common non-worrying sign.- A course of topical antibiotics: Watery eyes often lead to mucous production, which is distinct from pus discharge. Unnecessary topical antibiotics can cause secondary red eyes as well as give parents false expectations for the resolution of the symptoms and signs.- A course of topical and oral antibiotics: Watery eyes often lead to mucous production, which is distinct from pus discharge. Unnecessary topical and oral antibiotics can cause secondary red eyes as well as give parents false expectations for the resolution of the symptoms and signs.- Reassurance is necessary. However, the advice that the child most likely will need a surgical procedure to resolve this is incorrect. Reassurance, but include advice that the child most likely will need a surgical procedure to resolve this is incorrect as 90% of infants that have these symptoms and signs resolve within the first year of life.

When a child with joint problems presents with red-eye, the likelihood of anterior uveitis must be excluded by involving an ophthalmologist in the assessment. This is because uveitis is the most common extra-articular manifestation of juvenile idiopathic arthritis.Other options:- Cataract: It does not give rise to a red-eye, but leukocoria. Often this would have been picked up at an earlier age. – A patient with a corneal foreign body almost would almost invariably give a suspicious history (onset while playing outdoors etc.), as well as have marked symptoms of ocular discomfort (red, watery and painful eyes). – A child with periorbital cellulitis often presents acutely unwell and distressed. – A child with an uncorrected refractive error often complains of being unable to see in class and does not normally present with ocular redness.

Based on the clinical scenario provided, the most probable nerve injured in this patient would be the trochlear nerve. The trochlear nerve has a relatively long intracranial course, and this makes it vulnerable to injury in head trauma. Head trauma is the most frequent cause of acute fourth nerve palsy. A 4th nerve palsy is the most common cause of vertical diplopia. The diplopia is at its worst when the eye looks medially which it usually does as part of the accommodation reflex when walking downstairs.

Cataracts in infants are most commonly identified by an abnormal red reflex. Due to the high risk of amblyopia in unilateral cataracts, prompt referral to a paediatric ophthalmologist is indicated. Bilateral cataracts may occur in association with several syndromes or diseases, and these children require evaluation for these systemic disorders.Retinoblastoma is rare, but it is the most common primary intraocular tumour in children. About 80% of cases are diagnosed before age 4, with a median age at diagnosis of 2 years. It most frequently presents due to an abnormal red reflex. It is one of the few life-threatening disorders encountered in paediatric ophthalmology. Intraocular retinoblastoma is very treatable, but the mortality for metastatic disease is high. Identification of tumours before systemic spread is critical. Most children with large unilateral tumours will require enucleation (surgical removal of the eye), but the eye and vision may sometimes be preserved if the tumours are identified when they are small.

Aniridia is a genetic condition characterized by defects in the formation of a normal iris. The iris may be completely absent or only partially. One of the types of aniridia may be associated with other abnormalities like cataracts, glaucoma, corneal clouding, and nystagmus. The third type of aniridia is associated with intellectual disability, while a fourth type occurs in association with Wilm’s tumour. Aniridia may also be associated with amblyopia and buphthalmos, but macular hypoplasia is not a feature.

The most probable diagnosis in this patient would be hyphaema.The acuity has varied because the blood has been settling in the anterior chamber of the eye, thus allowing a reasonable level of visual acuity. The size of the tennis ball (which is not as harmful as a squash ball in the eye) and the fact that it was struck from a distance would cause a moderately significant injury due to pressure to the globe. Other options:- The absence of severe pain makes a large corneal abrasion less likely. – Vitreous haemorrhage would lead to very poor acuity, more likely ‘hand movements only’. – A retinal detachment or traumatic cataract would not produce such immediate symptoms, and if they did occur it would probably be in the presence of more extensive eye trauma and pain, with additional signs of both hyphaema and vitreous haemorrhage.