Clinical notes

These notes summarise the hospital management of common or serious retinal conditions. To navigate to a particular condition click on the link below:
If you have questions about a condition not listed on this page please do get in touch (contact details).

Age-related macular degeneration (AMD) 
 There have been important advances in the treatment of AMD in recent years, most notably the introduction of agents that inhibit vascular endothelial growth factor (VEGF). Anti-VEGF agents target the new vessels responsible for exudative (wet) AMD and the results of two large radomised clinical trial (MARINA and ANCHOR) establised ranibizumab (Lucentis) as an effective treatment.  Anti-VEGF treatment is available for many patients through the NHS, depending on their visual function and prognosis.  Because of the high drug cost of Lucentis, self-paying patients are often given Avastin off-label, a much cheaper agent that is chemically related to Lucentis.  Although Avastin has not been subject to a large trial like Lucentis, many clinicians feel it has a similar clinical effect.   I am currently a principal investigator for a new surgical treatmentof wet AMD that delivers a focal dose of radiation  to the macula via vitrectomy. Surgery has commenced recently at King's College Hospital, and it is anticipated that centres in Southampton and Belfast will soon follow. The potential advantage of radiation is that it can eradicate the new vessels that cause leakage in a one off procedure, unlike Lucentis which requires regular injections for life. The study is called CABERNET and the commercial spopsors are a US biotechnology company called NeoVista.  Preliminary results from America look encouraging, with visual outcome similar or better than Lucentis treatment, but until the CABERNET study is completed a firm conclusion on efficacy cannot be drawn. Patients wishing to be involved in this study should click here. Sadly, for atrophic (dry) AMD there are no breakthrough medical or surgical treatments on the immediate horizon - low vision aids remain the mainstay of treatment.  There is some interest in implantable telescopic lenses for dry AMD and a trial of these is underway at King's.  Contact details are available by clicking here. A guide to AMD referral is available by clicking here.  A patient information sheet is available here.

age-related macular degeneration
Severe, exudative, age-related macular degeneration

Diabetic retinopathy  The treatment of diabetic retinopathy has remained much the same for over a decade. Those with mild disease (NAD or background diabetic retinopathy) continue to require regular screening, such as annual photographs via DECS (diabetic eye complication screening).  Moderate to severe non-proliferative retinopathy is often reviewed regularly by an ophthalmologist.  More severe disease (proliferative retinopathy or maculopathy) is usually treated with laser - pan retinal photocoagulation (PRP) - to treat proliferating new vessels, or macular grid laser to reduce macular oedema.  Severe proliferative disease not responding to treatment, or vitreous haemorrhage from new vessels, may require vitrectomy and laser in a small proportion of patients.  Tight glucose control has been proven to slow the progression of diabetic retinopathy.  Control of hypertension is also important. For referral guidelines click here.  A patient information sheet is available here.

Retinal vein occlusion  Retinal vein occlusions can be divided into branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO), depending on which vessels are involved.  CRVO produces haemorrhage throughout the retina, whereas BRVO produces focal involvement.  BRVO is initially managed by observation alone, but if macular oedema develops a macular grid laser is often required and there are studies suggesting newer anti-VEGF agents such as Avastin may have a role to play.  BRVO and CRVO may develop new vessels that are treated by panretinal photocoagulation (PRP laser). Neovascularisation is usually a response to extensive retinal ischaemia.  In general, ischaemic vein occlusions do worse than non-ischaemic cases, particularly if the fovea is ischaemic.  CRVO macular oedema is difficult to treat and does not usually respond to grid laser. Recently people have been trying intravitreal steroid injections, and novel surgical techniques such as radial optic neurotomy (RON) which is available to select patients. Patients diagnosed with vein occlusion should have their cardiovascular risk factors carefully managed to reduce the chance of recurrence. Blood tests such as Full Blood Count, Fasting Glucose, Lipids, ESR and others may be appropriate to exclude underlying disease. Most patients with acute onset retinal vein occlusion should be seen by an ophthalmologist within approximately 1-2 weeks.

Vitreous floaters and posterior vitreous detachment Patients commoly have a 
few longstanding vitreous floaters in their vision or the occasional flash of light (photopsia).  These patients can be referred routinely to an optometrist with a request that they dilate the pupil and check the retina.  More worrying symptoms include a sudden increase in the number of floaters or change in their nature, significant photopsia, or field defects - in this setting retinal detachment needs to be promptly exluded with same-day ophthalmology review.  Risk factors for retinal detachment include high myopia, complicated cataract surgery, trauma, a postitive family history, and previous retinal detachment in either eye.   The commonest differential of photopsia is migraine but this is usually experienced in both eyes simultaneously, unlike vitreoretinal photopsia that usually occurs in the temporal field of one eye. The commonest finding in patients referred to hospital with new floaters is a posterior vitreous detachment. This occurs when the vitreous gel collapses, and the posterior surface of the vitreous separates from the retina.  It is not in itself harmful, however, it can be a prelude to retinal tears and detachment in a small minority of patients and thus careful fundus examination is important.  A patient information sheet is available here.  For patients who present with floaters always provide a retinal detachment warning, advising them to present immediately if they develop flashes, increasing floaters, or a visual field defect.

Retinal tears and holes Retinal tears usually occur when the vitreous pulls away from the retina (see posterior vitreous detachment above) and an abnormally strong vitreoretinal adhesion pulls a break in the retina.  These typically have a U-shaped or horseshoe configuration and acute tears usually require treatment (retinopexy) with laser or cryotherapy to reduce the risk of retinal detachment. Longstanding tears sometimes lead to a healing response that creates an adhesion between the retina and the underlying RPE (retinal pigment epithelium), creating much the same effect as retinopexy - in this setting retinopexy may not be required. 

A U-shaped, horseshoe tear surrounded by laser retinopexy

Retinal holes have a different pathogenesis - they are round atrophic defects in the retina that can occur without posterior vitreous detachment. They may occur in eyes with lattice degeneration, a thinning of the retina associated with myopia.   Round holes can lead to retinal detachment but it is not proven that retinopexy reduces this risk. In the past they were usually  treated, but this is becoming less common.  Symptomatic retinal tears should be seen by an ophthalmologist the same day, whereas atrophic round holes picked up during a routine optician examination can be referred routinely.  Asymptomatic retinal tears should be seen by an ophthalmologist semi-urgently (1-2 weeks). Provide all patients with a retinal detachment warning, advising them to present immediately if they develop flashes, floaters, or a visual field defect. 

Retinal detachment Retinal detachment is usually occurs when a posterior vitreous detachment pulls a break in the retina, and vitreous fluid passes into the potential space between retina and RPE (retinal pigment epithelium). Detached retina does not see so the patient experiences an enlarging visual field defect. If the detachment extends to involve the macular (a macular-off retinal detachment), then visual acuity drops precipitously.  Occasionally, retinal detachments are asymptomatic.  

Retinal detachment
A superior macular-on retinal detachment

Treatment involves one of three strategies: pneumatic retinopexy, cryobuckle surgery, or vitrectomy/laser/gas. Pneumatic retinopexy is reserved for a small number of straightforward detachments; it has the advantage that it is a simple procedure, but it has a fairly high failure rate, with about 30% of cases going on to require cryobuckle or vitrectomy.  Cryobuckle involves the use of scleral explants to indent the sclera/RPE in apposition to the retina. The retina-RPE are then sealed together with a laser or cryoprobe.  Vitrectomy involves removal of the vitreous gel, and a gas bubble to push the retina onto the RPE from within the eye, and again, laser or cryoprobes are used to seal the break.  Because of the gas bubble patients have certain restrictions after surgery and these are outlined in the patient information sheets posted elsewhere on this website.   Occasionally, asymptomatic, chronic retinal detachments are detected during routine optician examination, and these can be referred to an opthalmologist semi-urgently (1-2 weeks), however in all other situations patients require same-day ophthalmology review and shoud be kept nil by mouth.  Refer to a centre with a Vitreoretinal Service, such as King's College Hospital.

Macular hole The exact pathogenesis of macular holes is not known but the end result is a full-thickness defect centred on the fovea. As expected this produces a central visual defect with blurred vision and distortion. 

OCT macular holemacular hole
Macular holes seen on OCT (left) and a fundus photograph (right).

Without treatment only a small minority of macular holes resolve and surgery is usually recommended, unless the macular hole has been present for a very long time (2 years of more), when the visual prognosis is guarded.  Surgery involves vitrectomy and gas, and leads to hole closure in 80-90% of eyes. Not all eyes with closure of the hole have visual improvement, but most have an appreciable improvement. Fully normal vision is seldom achieved. Patients should be referred to a Vitreoretinal Surgeon, routinely.  Patient information is available here. 

Epiretinal membrane An epiretinal membrane is a thin layer of scar tissue on inner surface of the retina.  It usually occurs at the macula.  Contraction of the membrane causes corrugations in the fovea that distort the patient's vision, with straight lines appearing bent or bowed. It can occur in isolation or in association with other eye disease such as peripheral retinal breaks, posterior uveitis, and trauma.  Treatment involves surgical removal with vitrectomy and membrane peel. This usually, but not always, improves the distortion.  The effect on visual acuity may be less marked but some benefit is common.  Sometimes the membanes recur and repeat surgery is required. Patients should be referred to a Vitreoretinal Surgeon on a routine basis.  

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