Group 27 have shown that photocoagulation is effective in the treatment 

of proliferative retinopathy. Treatment is particularly effective when 

given early and adequately and joint initiatives for screening for diabetic 

retinopathy as shown by the Brunel study1.

.

Similarly the British and Study28 and the Early Treatment of Diabetic 

Retinopathy Study14 have shown that visual loss due to diabetic 

maculopathy can be reduced, especially when the lesion are early, and 

the vision still good.

.

As the earliest forms of retinopathy, when treatment is also most 

effective, are not associated with visual symptoms, it is essential that 

these should be detected. DR therefore represents an excellent paradigm 

for screening as laid out in the principles for screening of human disease29. 

Screening for diabetic retinopathy is cost effective in health economic 

terms30-32. 

.

Comprehensive screening programmes for DR in the UK are difficult 

to put in place since there is as yet no complete register of all diabetics 

in all health regions. however, attempts should be made to achieve full 

coverage of the patient population through the establishment of district 

wide diabetes registers.

.

Screening may be undertaken for two reasons: the detection of disease 

of any severity and the detection of disease of sufficient severity to 

require consideration for treatment. The latter constitutes the 

"indications for referral to the ophthalmologist" and is dealt with below.

.

Screening modalities include fundoscopy, which can be performed by 

various individuals with different levels of expertise, and photography 

with a fundus camera with or without mydriasis.

.

Several studies on the value of screening11,30,32-39 have led to the 

following general recommendations proposed in a parallel guidelines 

document in preparation by the European Consensus Document and the 

conference of Scottish Royal Colleges:

.

• all patients aged over 12 years and/or entering puberty 

should be screened
.
• screening should be performed annually and should 

include a measurement of visual acuity and examination 
of the fundus through a dilated pupil
.
• screening should be performed in the most appropriate 

and comprehensive manner and will involve a combination of:
.
a. diabetologists for patients attending hospital diabetic 
    clinics
.
b. optometrists, usually in densely populated urban areas, 
    as primary screeners for diabetic patients being treated 
    by their general practitioner, if the GP does not wish to 
    perform the screening him/herself
.
c. photographic screening for patients for whom neither of 
    the above is available eg. in rural communities. Photographs 
    would be evaluated by primary screeners at diabetic clinics 
    or GP practices.

.

Combined modality screening may be useful in certain circumstances. 

In this case the opinion of a trained ophthalmoscopist, whether 

physician, ophthalmologist or optometrist, is combined with photography 

through a dilated pupil, the photographs being evaluated by a trained 

observer. While labour intensive, the number of missed is greatly reduced. 

Whichever screening method is employed in any region, it is important 

that the results of screening and indeed treatment outcomes from the 

screening programme, are audited and validated.

.

With rapid advancement of technology, new methods for screening are 

now available including digital photographic and computerized methods for 

detection and assessment of retinopathy. While opinions remain divided 

as to the best screening modalities, it should dbe possible to develop an 

effective screening programme based on a single modality, thereby 

reducing duplication, cost and sources of error. A number of research 

programmes are currently in progress to evaluate the various modalities. 

All new screening methods however, should be tested for sensitivity and 

specificity against known standards. In addition, the screening procedure 

in each centre should be audited regularly by independent assessors to 

ensure uniform standards of care.

.

4.2 Indications for referral to an ophthalmologist

The main purpose of screening is to detect patients who require treatment 

and to refer them to the ophthalmologist in good time, when vision can be 

saved, or possibly improved.

.

Urgent referral is indicated in the following conditions:

• new vessels on the disc
• new vessels elsewhere
• preretinal and/or vitreous haemorrhage
• rubeosis iridis
• retinal detachment

.
These patients should be seen on the same day in the case of retinal 
detachment and vitreous haemorrhage and within 2-3 days in the 
case of new vessels.

.

Early referral is indicated in the following conditions:

• "high risk", pre-proliferative retinopathy
• non-proliferative retinopathy with macular involvement
• haemorrhages and/or hard exudates within one disc diameter from 

the centre of the fovea
• reduced visual acuity not corrected pinhole, suggestive of macular oedema.

These patients should be seen within 3-4 weeks.

.

• non-proliferative retinopathy with large circinate or plaque exude 

within the major temporal arcade but not threatening the macula
• retinal findings that are not characteristic of diabetic retinopathy
• background retinopathy with reduced vision but without maculopathy 

to determine cause of visual loss.