Ординатура / Офтальмология / Английские материалы / Handbook of Retinal Screening in Diabetes_Taylor_2006

Figure 11.8 Pre-retinal haemorrhages

Disc

The disc margins are unremarkable. There is an indistinct red area over the upper and left-hand part of the disc. This is fibro-vascular tissue resulting from previous new vessel formation.

Vessels

The veins are engorged. There is some variation in calibre of the veins.

Retina

Multiple blot haemorrhages are present. At 3 o’clock to the disc there is a moderate sized pre-retinal haemorrhage. Below the disc there is a large pre-retinal haemorrhage which must have been present for sometime given that the blood cells have settled under gravity to cause the straight upper border. Some small dilated vessels can be seen towards the left-hand side of the disc, and are likely to be IRMA. A third preretinal haemorrhage extends over the macular region. Microaneurysms and more blot haemorrhages are present in the upper left-hand portion of the image.

Figure 11.9 Fibrous band and heavy laser scars

Disc

The disc is unusually pale, probably as a result of poor microvascular circulation at the nerve head.

Vessels

The major vessels are poorly seen, being partially obscured by fibrous tissue extending forwards from the plane of the retina.

Retina

The distinct white band of fibrous tissue is attached to a small area of the retina near the fovea. Further contraction could cause distortion then detachment of the retina with catastrophic results upon the visual acuity of this eye. Visual acuity has been preserved by the photocoagulation over 10 years earlier (6/09) despite peripheral field defects. The very heavy laser therapy was necessary to halt the proliferative process which continued after standard pan-retinal photocoagulation.

show no change compared with previous images. The concern is that the dark spot is a malignant melanoma requiring urgent ophthalmological assessment and treatment.

Congenital retinal disorders may be seen and retinitis pigmentosa is most frequently encountered. People with this familial progressive disease will usually already be under ophthalmological care.

Central and branch vein retinal occlusions require ophthalmological assessment. Cholesterol emboli are likely to be associated with high blood cholesterol levels, and simple tablet treatment saves lives.

Other eye diseases

Glaucoma

Two very different diseases can cause raised pressure in the eyeball and they are often confused.

Chronic glaucoma (also known as open angle glaucoma) is common and by itself is the third commonest cause of blindness registration in the UK. It is caused by relative blockage of the outflow of aqueous humour through the trabecula meshwork into the canal of Schlemm. Chronic glaucoma is very gradual in onset and can cause substantial loss of vision before it is diagnosed. The optic disc may have an abnormally large cup. Older people are mainly affected, and 10 per cent of relatives are likely to develop the condition. Treatment is usually by the use of eye drops (e.g. timolol, latanoprost). Tropicamide eye drops do not constitute any risk for people with chronic glaucoma or their family members. Use of mydriatic drops is irrelevant to the cause of this condition.

Acute glaucoma (also known as angle closure glaucoma) is much less common and has less of a family tendency. It presents acutely as a painful, red eye and urgent ophthalmological treatment is essential. Predisposed people have a narrow angle between the cornea and the iris (see Figure 3.1) and sudden blockage of drainage to the canal of Schlemm can happen at any time. Treatment is by laser or surgery to create a hole in the iris, and this is done in both eyes. Once this has been done there is no risk of recurrence and

mydriatic eye drops of any kind may be used. The great cloud of worry about this subject has been created entirely because people who are just about to develop acute glaucoma may have the condition precipitated by use of strong or combined mydriatic drops (such as atropine, cyclopentolate). This is a rare event. Even for such people in the days before they suffer the acute attack, the relatively weak tropicamide is extremely unlikely to precipitate acute glaucoma when used as a single agent.

Conjunctivitis

Inflammation of the conjunctiva is most often due to infection. Allergy or physical irritation may also cause a similar appearance. Viral conjunctivitis is very contagious and strict hygiene must be observed for any red eye. Expert diagnosis is necessary.

Sub-conjunctival haemorrhage

A minor leak of blood under the conjunctiva can cause an alarming appearance of uniform redness where there should be white conjunctiva. It may involve the whole or only part of the conjunctival area, and usually only affects one eye. Often no cause can be found, but it is typically associated with a bad coughing bout. A sub-conjunctival haemorrhage always gets completely better with no treatment and is of no concern whatever.

Uveitis

Uveitis is an inflammatory condition of the ciliary body and iris. It tends to be associated with systemic diseases such as inflammatory arthritis (e.g. ankylosing sponylitis, Reiter’s syndrome, systemic lupus).

Box 12.1 Glaucoma

Chronic glaucoma

Due to slow drainage of aqueous humour from the eye even though the angle between the iris and the pupil is normal.

Also known as open-angle glaucoma (and is unaffected by mydriatic drops).

This is the common form of glaucoma. Tends to run in families.

Acute glaucoma

Due to blockage of drainage of aqueous humour from the eye because of closure of a narrower than normal angle between the iris and the pupil.

Comes on suddenly with pain and redness of eye.

In susceptible people it can be precipitated by strong mydriatic drops such as those used by ophthalmologists.

It cannot be precipitated by tropicamide (0.5 or 1 per cent) unless spontaneous acute glaucoma was just about to happen anyway.

Treatment

Chronic glaucoma is usually treated with regular eye drops (such as timolol). Such treatment is not a contraindication to the use of tropicamide.

Acute glaucoma is usually treated by creating a drainage hole through the iris either by laser or by surgery. Both eyes are treated, and after such treatment there is no contraindication to the use of tropicamide.

The myth that tropicamide eye drops cannot be used in people with established glaucoma is simply without basis. The myth has created a real risk to eyesight by causing failure to screen properly for diabetic retinopathy.

Figure 12.1 Drusen

Disc

The optic cup is well-defined and normal. Colour elsewhere on the disc is normal apart from a small linear haemorrhage. The disc margins are not clear but are within normal appearances.

Vessels

Normal.

Retina

Small, approximately round lesions are evenly spread over the central retina. Each is slightly indistinct and pale but not white. The most diagnostic feature of Drusen spots is that they are fairly uniformly distributed in most cases, as opposed to the random occurrence or clustering of exudates. If the white lesions are as obviously close to the fovea as in this case and the visual acuity is normal, the lesions are unlikely to be exudates.

Figure 12.2 Drusen

Disc

Unremarkable, with normal cup, margins and small vessels.

Vessels

Normal.

Retina

Examination of the peripheral retina is unremarkable, with normal variation of background colour. Close to the fovea there are several pale areas, most of which are indistinct. One appears more prominent. Visual acuity was normal, and because a confident diagnosis could not be made ophthalmology referral was arranged. All lesions were confirmed as Drusen spots.

Figure 12.3 Atrophic chorioretinital scars

Disc

The colour, margins and small vessels are unremarkable.

Vessels

The veins are normal throughout with some light reflection especially in the lower part of the image. The diameter is somewhat greater than normal, approaching 3 : 2 compared with arteries.

Retina

Several very pale, well demarcated lesions are scattered over the retina. The shape varies, and some contain dark areas of pigment clumping. The retinal vessels frequently run across the lesions. The patient reported no previous eye trouble or serious illness and vision was perfect. The appearance of focal inflammation from many years ago can be expected to remain stable. There are also widespread microaneurysms and blot haemorrhages. The two small round pale spots in the macula region (one at 4 o’clock and one at 8 o’clock to the fovea) deserve comment. They look too regular and too tiny to be exudates. They are tiny intra-retina cysts.