Ophthalmic diagnoses are dependent on a good, thorough history, which can help narrow down the differential diagnoses and help suggest the disease and its cause. A good history can also identify the parts of the clinical examination that need special attention and indicate a need for particular additional investigations. In addition, the history may reveal 'red flag' symptoms that can help identify which patients need urgent specialist referral.
Ocular history taking is similar in structure to a general medical history. However, note the important addition of past ocular history (Figure 1).
As with all histories, start with open questions and let the patient describe their symptoms in their own words. Direct questioning is used to clarify information such as ocular symptoms, time of onset, which eye is affected and non-ocular symptoms.
It is important to ask about the patient's other eye if the patient presents with unilateral symptoms.
History of the presenting complaint:
If the patient complains of pain, use the 'SOCRATES' method of questioning e.g. ask about the site (unilateral or bilateral), onset (gradual or acute), character, timing (e.g. how long the eye has been red), exacerbating/relieving factors and severity.
Ask about any associated symptoms that can help you narrow down the diagnosis. Remembering the list of specific questions to ask can be a little tricky. To help remember, think about the anatomy and structures of the eye that may be affected. For example, start with the eyelids and adnexae and work 'backwards' towards the visual cortex; ask about the conjunctiva and sclera (conjunctivitis, slceritis), anterior chamber (glaucoma), lens (cataract), retina (flashes, floaters, etc) and lastly general questions such as headaches. Here are some of the possible questions that you might want to ask:
The 'floaters' that patients complain about are caused by fragments of condensed vitreous which result from degenerative changes in older patients. When patients complain of flashing lights (photopsia), this suggests posterior vitreous detachment, caused by the collapse of vitreous gel. Some patients may describe a 'shower of floaters' associated with photopsia, representing condensations within the collapsed vitreous.
These symptoms of posterior vitreous detachment may precede retinal detachment, where the patient may then complain of a progressively developing field defect, described as a 'shadow' or 'curtain'.
The 'timing' of the symptoms is also very important. For example, in patients who present with reduced visual acuity, it is important to know if it was of acute or gradual onset. Another example is the patient with blepharitis, whose symptoms may be worse in the morning.
Don't forget to ask about systemic features as well, e.g. any fever, malaise, vomiting, arthralgia, rashes, headache and facial pain.
Enquire about possible precipitating factors:
For patients whose symptoms are associated with a history of trauma, careful questioning is required. It is essential to ask about the form of injury, as each type of injury is associated with different complications.
For example, a flake of metal from the use of a hammer and chisel can penetrate the sclera and cause subconjunctival haemorrhage with minor pain. Other foreign bodies may become lodged under the eyelid.
Blunt trauma may result in damage to the orbit, causing a blow-out fracture. History of a high-velocity object (such as shuttlecocks, squash balls and champagne corks) can cause blunt injury to the eye. Patients with a blow-out fracture may have enophthalmos with limitation of eye movements, particularly upgaze and downgaze.
It is also essential to ask about any possible chemical or radiation injury in trauma. Strong alkalis can penetrate the anterior tissues of the eye, making the conjunctiva appear white.
Also ask about any self-treatment measures taken or treatment received from health professionals already and what the patient thinks might be wrong.
Figure 3 shows two common presenting symptoms with some questions to ask for each symptom.
Ask about previous ophthalmological problems including:
Also enquire if the patient has had a recent sight test to exclude an uncorrected refractive error. Myopia has been associated with retinal detachment and early onset vitreous degeneration, while hypermetropia has been associated with increased risk of acute angle closure glaucoma and pseudopapilloedema.
Other conditions to look out for in the past medical history:
Ask the patient what medications he or she is taking. Some drugs such as isoniazid and chloroquine may be toxic to the eye. Steroid use is associated with posterior subcapsular cataracts.
Also ask if the patient takes any eye drops, e.g. for glaucoma.
IMPORTANT: Ask about any drug allergies.
Drugs and their delivery vehicles and preservatives may stimulate an allergic reaction, which might cause a red eye presentation in a patient.
Also bear in mind systemic drugs that can cause ocular side effects. Table 1 shows some common systemic drugs and their ocular side effects.
Ask if there's a family history of ocular problems such as glaucoma, and ocular diseases that are known to be inherited such as retinitis pigmentosa. A family history of strabismus, refractive errors or amblyopia can help the diagnosis when faced with a child presenting with a squint.
Also ask if there's a history of albinism, a group of inherited abnormalities of melanin synthesis. There are two types: ocular albinism (X-linked and recessive forms) associated with lack of pigmentation confined to the eye; and oculocutaneous albinism (recessive) where the hair and skin are also affected.
Other ophthalmological conditions that have less well-defined associations include presenile cataract, retinal/corneal dystrophies and retinal detachment. The juvenile macular dystrophies are also a group of rare inherited conditions affecting the retinal pigment epithelium and photoreceptors.
Enquire if there's a family history of diabetes, hypertension, etc.
Apart from asking the usual questions such as about occupation, smoking, alcohol and the patient's everyday circumstances, a sexual history can help in diagnosing Reiter's syndrome, where the patient can have ocular problems such as uveitis or conjunctivitis.
It is important to understand the patient's social circumstances as this is important when planning for arrangements after surgery (e.g. suitability for day case surgery). For patients with visual impairment, it is also important to be able to empathise and understand the functional impact and social repercussions of the patient's condition. Ask about indicators of function such as reading, driving, shopping, etc.
There might be a profound impact on the patient's occupation due to severe irreversible visual impairment. Visual loss can also impair driving on the road. Visual requirements for driving include the ability to read a number plate (in good light, with or without corrective lenses) at a distance of 20.5m, which corresponds to a binocular visual acuity of 6/10 on a Snellen chart. It is possible to drive with one eye if the visual requirements are met.
Enquire about the patient's housing arrangements and the level of support at home as some patients with visual impairment might not be able to mobilise safely without the risk of falling. This is particularly important in older patients who are at risk of falls.
At the end, complete the history with a systems review, and summarise back to the patient to make sure you haven't missed anything important.
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