How much is your general practice work really worth?
Dr Paul Payne shares his tips gained from working as both a GP in south Gloucester and hospital practitioner in ophthalmology at Bristol Eye Infirmary
1. Cataracts are the single most common cause for referral by GPs to ophthalmologists and account for more than 70 per cent of their surgical workload. More than 50 per cent of patients over the age of 80 will be affected. There are both medical and social implications of reduced acuity and these often have a bearing on the referrals.
2. The most common presentation is reduced visual acuity, but they can also cause glare. Another common presentation is 'index myopia', where the change in the refractive index of the lens itself results in an increasing myopic shift that often results in frequent changes in refraction and subsequent spectacle changes.
3. Cataracts can be seen with an ophthalmoscope. The examiner should stand about half a metre in front of the patient with a +3 lens in front of the viewing aperture and direct the beam of light through the pupil where the cataract will appear as a black shadow across the normal red retinal reflex.
4. Most cataracts are of the senile variety and are usually nuclear. When viewed on a slit-lamp appear they appear as an amber-coloured central opacity. The less common posterior cortical cataract appears as a lace-like opacity at the posterior surface of the lens. Congenital cataracts are often familial, but any interference with lens development in the first trimester of pregnancy conveys a definite risk of cataract formation.
5. Secondary cataracts are seen following chronic anterior uveitis, as a sequel to trauma that can be either penetrating or blunt, and includes certain surgical techniques, especially those required following retinal detachment. Radiation may also result in cataract formation.
6. Other conditions associated with cataracts are the metabolic group that includes diabetes mellitus, hypocalcaemia, and dystrophia myotonica. Some skin conditions such as atopic dermatitis are sometimes associated with subcapsular cataracts.
7. Steroids given over a long period either systemically or topically can produce posterior cortical cataracts that can markedly interfere with vision. Chlorpromazine is also implicated, although the resulting opacities have less impact on visual acuity.
8. Treatment, contrary to some public belief, is always surgical and is nowadays performed by a relatively non-aggressive sutureless procedure almost always under local anaesthetic as a day-case. The use of flexible intraocular lenses is now routine, and patients are assessed preoperatively to assess the strength of the lens required.
9. Complications of surgery are rare. Immediate causes are infection, and in the case of endophthalmitis can have devastating consequences. Haemorrhage and retinal detachment are rarely seen. Due to the small size of the modern corneal section, iris prolapse is rarely seen. The most common late complication is that of opacification of the posterior capsule, which can easily be remedied by YAG laser capsultotomy.
10. Driving acuity is slightly better than 6/12, and early cataracts can make this impossible, and this in itself is an indication for extraction. With modern surgical techniques, there is no longer a need to wait until a cataract is 'ripe' before it can be removed.