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Missed Opportunities and Lost Vision

Medico Legal

by Mr Kim Hakin. An ever increasing ageing population, the advent of new treatments, improved community screening (that increases referrals) and perpetually rising expectations, could be said to have combined to create a “perfect storm” in healthcare, and in the UK, a demand that far outstrips the capacity of the NHS and its ability to cope. Nowhere is this more apparent than in the field of ophthalmology.

Cataract surgery, that comprises the majority of ophthalmic operations, is the most frequently performed operation in the UK, and has received considerable attention and investment in recent years as successive governments have sought to reduce waiting lists and times for surgery. Ophthalmology, however, also has a significant outpatient workload and indeed, in terms of outpatient episodes, is frequently the busiest outpatient department of a general hospital. The majority of outpatient visits are for one (or more) of three chronic conditions, ‘wet’ macular degeneration, glaucoma, and diabetic eye disease, all of which require regular long-term review, and can lead to irreversible loss of vision without timely treatment.

The chronic nature of these conditions results in an inability in most cases, to discharge patients from the Hospital Eye Service – GPs are not able to undertake any continued management, whilst the numbers of optometrists who are appropriately trained and able to contribute to care, are minimal. As a result, there is a seemingly exponential buildup within ophthalmology departments nationwide, of unquantifiable numbers of patients requiring follow-up appointments and essential treatment, that in some cases cannot be adequately provided, causing a number of patients (with a likely much greater number yet to be identified) to suffer irreversible but potentially preventable loss of vision, that has then proceeded to litigation.

Wet’ Age-Related Macular Degeneration

Age-related macular degeneration (ARMD) describes the age-related degenerative change of the macula, the central area of the retina responsible for central vision. Degeneration of the macula typically results in loss of central vision (acuity), distortion of central vision and loss of colour vision. ARMD may be “dry” where there is a gradual of thinning and degeneration of the macula, typically associated with slow deterioration of central vision, or “wet”, which is characterised by the development of new, abnormally fragile blood vessels in the macula area that usually results in a considerably more rapid loss of vision. Wet ARMD may occur de novo, or in an area of existing dry ARMD. At one time, neither type of ARMD was treatable. In 2006, however, US FDA approval was granted for the treatment of wet ARMD with intraocular injections of Lucentis, an ‘anti-VEGF agent’, that can lead to shrinkage of the blood vessels with stabilisation and in some cases, improvement of vision. NICE gave its approval for use in the NHS in 2008, a decision that was widely welcomed, but which several years on, has resulted in considerable capacity and financial issues for the NHS due to the overwhelming demand for treatment.

Where a patient with ‘wet’ ARMD may have previously been seen once in the ophthalmology clinic, essentially for a diagnosis to be made before being discharged with an untreatable condition, many more patients with suspected ARMD are now needing to be seen and investigated to identify any treatable condition, with those considered likely to benefit, then receiving treatment and being subsequently reviewed and re-treated as required. Review may be required as frequently as every month, and almost indefinitely, until eventual disease stability or burn-out has occurred, or in view of the age of the typical patient, their passing. (The initial multi-centred studies that confirmed the efficacy of Lucentis, involved monthly injections for 24 months). There is a limited window of opportunity for the treatment of ‘wet’ ARMD, before irreversible retinal damage has occurred, when treatment with Lucentis will be of benefit, and it is essential therefore, that at risk patients are monitored on a regular and timely basis. If review is delayed and a treatable condition not appropriately treated, irreversible retinal changes with permanent loss of central vision will occur. It is easy to understand, therefore, with an increasingly elderly population, how the demands on an ophthalmology service have risen so quickly and significantly, and in some cases, have exceeded the ability to provide a satisfactory service, with patients failing to receive adequate and appropriate treatment, and potentially disastrous consequences.

Diabetic Eye Disease

Diabetic retinopathy describes the damage to the retina in diabetic patients, which may eventually lead to complete blindness. It can affect up 80% of patients who have had diabetes for 10 years or more, although vigilant screening and treatment of diabetic patients, as is now commonplace, can significantly reduce the risk and extent of visual loss. The risk of developing diabetic retinopathy increases with increased duration of disease and poor diabetic control, and smoking. Diabetic retinopathy is caused by abnormal changes in the small blood vessels within the retina that may leak fluid or bleed, that in turn lead to swelling and reduced function of the retina with subsequent reduction in vision. Diabetic change affecting the macula is described as maculopathy and will invariably result in loss of acuity. In other patients, retinopathy may become manifest when there is rupture and bleeding of (abnormally fragile) new blood vessels that grow on the surface of the surface of the retina (proliferative retinopathy). The development of these abnormal blood vessels can, furthermore, lead onto the development of retinal detachment that may result in total and irreversibly loss of vision without, and even with, treatment. It is important to note that diabetic retinopathy may occur, and even reach an advanced stage, without symptoms, hence the introduction of a nationwide retinopathy screening programme that attempts to annually screen (in the community) for the development of diabetic eye disease in all diabetic patients.

Laser treatment of diabetic retinopathy has transformed the outcome of diabetic eye disease, significantly reducing the incidence of blindness, although as with ‘wet’ ARMD and glaucoma, it is essential that treatment is undertaken before the onset of irreversible retinal change; hence the importance of initial screening for the condition, and upon diagnosis of sight-threatening disease, regularity of review. A patient with significant diabetic eye disease will generally require indefinite review, leading to an increasingly growing cohort of ‘follow-up’ patients for whom appointments will be required but in some cases cannot be provided, at least not within an appropriate time-frame, that can then lead to unchecked progression of diabetic eye disease and irreversible loss of vision.

Glaucoma

Glaucoma is the name given to a group of disorders in which the intra-ocular pressure (IOP) is sufficiently elevated to cause loss of vision. The most common form of glaucoma is chronic open angle glaucoma (COAG), affecting approximately 1 to 2% of the population over 40, with the prevalence increasing with age such that 10% of people over 70 may be affected. It is responsible for 10 to 12% of all cases of blind registration in the UK. COAG is characterised by a progressive chronic rise in IOP, above the normal range of 16-21 mmHg, that results in irreversible damage to the optic nerve (visible as “cupping” upon examination) with commensurate slowly progressive loss of visual field, usually occurring over many years. The rise in pressure is thought to be increased resistance to outflow of aqueous humour circulating within the eye through the trabecular meshwork, a circumferential sieve-like structure sitting in the angle between the iris and cornea through which 90% of the aqueous humour is thought to drain.

Due to its insidious onset, symptoms of COAG are typically few and late, with the patient becoming aware of its presence only at the advanced stage when significant visual field loss has occurred. In most cases however, at least in the UK, the condition is identified in its early stages by optometrists upon ocular examination in the course of spectacles prescription. The extent and progression of COAG within an eye is assessed by examination of the optic disc and measurement of the degree of “cupping”, and by the assessment of the visual field. Glaucomatous cupping of the optic disc will lead to typical visual field defects, although considerable optic disc damage and cupping may occur before a field defect arises. Although COAG cannot be prevented, it is universally accepted that reduction of an elevated IOP will reduce the risk (but not completely abolish) of progression of glaucomatous optic neuropathy and subsequent visual field loss. Initial treatment is typically with eye drops, of which there are several “classes”, each with a different mode of therapeutic action; many patients can achieve satisfactory control with the use of one drop only whilst others may require a combination of two or more different types of drop. If the IOP cannot be reduced to the desired target pressure, laser and/or surgery maybe required.

As glaucomatous optic neuropathy and subsequent loss of vision are irreversible, screening for the condition with prescription of hypotensive treatment is essential if loss of vision from glaucoma is to be prevented – one reason why in the UK, anyone over the age of 40 is advised to visit their optometrist on a regular basis. Individuals with glaucoma require life-long monitoring, at intervals appropriate for the extent and control of their condition, with adjustment and increase in treatment as necessary, and will generally remain indefinitely under the care of the Hospital Eye Service.

Whilst there is considerable pressure on hospital Trusts to provide initial treatment of any referred patient within 18 weeks of referral (with severe financial penalty in the event of failure to treat within this time), no such ‘targets’ exist following that initial treatment, and as a result therefore, there is less focus or perceived incentive to deal with those patients who have joined the ranks of ‘follow-ups’, but who still require regular review and frequently, active management of potentially sight-threatening disease. With the continuous ‘one-way’ stream of patients who enter but do not exit from ophthalmology departments, it is perhaps therefore not unduly surprising to discover that some patients are being failed by the system, with profound consequences, and that this is likely to continue whilst there is no resolution of the underlying causative factors. ?

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