Ординатура / Офтальмология / Английские материалы / Fundamentals of Clinical Ophthalmology Cornea_Coster_2002

Indications

1.

In limbal stem cell deficiency amniotic membrane transplantation

can be done in combination with stem cell graft.

2.

Chemical injuries

3.

Persistent epithelial defects

4.

Painful bullous keratopathy

5.

Conjunctival cicatrisation

Setting

Operating room

Equipment required

1. Speculum

2.

Plain forceps

3.

Conjunctival forceps

4.

10.0 nylon suture, 8.0 polyglactin 910 suture

5.

Bandage contact lens

Anaesthesia

1.

Topical

2.

Regional – local infiltration, peribulbar, subtenon

Procedure

1. The amniotic membrane is gently spread on a prepared

corneal surface and trimmed to the appropriate size

2.

In corneal/limbal diseases the membrane should be larger than

the area involved

3.

Fix the amniotic membrane with 10.0 nylon and 8.0 polyglactin

910 on the cornea and conjunctival ends respectively

4.

In conjunctival surgery, it is used to cover conjunctival defects,

using a spacer to maintain fornices

5.

A bandage contact lens is then placed for comfort and

also to hold the graft

Complications

1.

Operative – haemorrhage, perforation of globe

2.

Postoperative – failed epithelialisation, fibrosis, infection

Follow up and postoperative care

1.

The contact lens and sutures are removed after 2–4 weeks

2.

Topical antibiotics and corticosteroids – preservative free are preferred

PROCEDURES

Botulinum toxin-A induced ptosis

Indications

1.

Some persistent epithelial defect

2.

Exposure keratopathy

Setting

Procedure room

Equipment required

1.

Botulinum toxin-A (reconstituted with isotonic saline to the

appropriate dilution) 62.5 picagrams in 0.1 ml

2.

A 25 mm, 25 gauge needle or a tuberculin syringe

Anaesthesia

Local to skin or not required

Procedure

The skin is penetrated immediately below the central part of

the superior orbital rim and the needle passed backwards along the

orbital roof for 25 mm. The effect lasts for seven days to five weeks

Complications

1.

Transient ipsilateral superior rectus palsy

2.

Haemorrhage

Indications

1.

Suspected conjunctival malignancy

2.

To establish a diagnosis of systemic diseases with conjunctival

involvement, e.g. sarcoidosis

3.

Early diagnosis of suspected autoimmune conjunctivitis

Setting

1. Procedure room with operating microscope

2.

Operating room

Equipment required

1. Speculum

2.

Conjunctival forceps (plain)

3.

Conjunctival scissors

Anaesthesia

1.

Topical

2.

Regional – local infiltration, peribulbar, subtenon, subconjunctival

Procedure

1.

Identify the site or sites for biopsy

2.

A subconjunctival injection of 2% lignocaine

3.

Gently dissect the lesion. Minimise handling the tissue as this can

create artefacts

4.

If the lesion is large multiple biopsies can be done

5.

Each biopsy is placed in a separate bottle accompanied by a map

Managing the specimen

1.

Histopathology – isotonic buffered formaldehyde

2.

Immunohistochemical staining (autoimmune diseases) – direct

immunofluorescence fixative

Follow up and postoperative care

1.

Topical antibiotics, e.g. chloramphenicol until the conjunctiva heals

PROCEDURES

Conjunctival flap – Gunderson’s

Indications

1.

Corneal perforation which has failed to respond to other modalities

of treatment and not suitable for keratoplasty

2.

Corneal oedema (painful bullous keratopathy)

3.

Chronic epithelial defects which have failed to respond to

conventional medical therapy

Setting

1. Operating room

Equipment required

1.

Speculum

5. Plain forceps

2.

4.0 silk suture

6. 6.0 polyglactin 910 suture

3.

Bard Parker no. 15 blade

7. Needle holder

4.

Conjunctival scissors

Anaesthesia

1.

Regional – local infiltration with 1% lignocaine with epinephrine

(1: 100 000) peribulbar, subtenon

Procedure

1.

Place a superior rectus bridle suture

2.

Once the local anaesthetic has been administered, the conjunctiva is

cut 15–18 mm above the superior limbus for approx. 30 mm

horizontally. Avoid tenons. Dissect inferiorly till the superior limbus

3.

Next a 360 periotomy is performed

4.

Prepare the corneal surface by removing the corneal epithelium and

necrotic stroma, if present, by gentle scraping with a blade

5.

The flap is now placed over the cornea and secured with 6.0

polyglactin 910

6.

The original conjunctiva of the lower limbus is approximated to the

lower border of the bridge flap, closed with two interrupted sutures.

Repeat for the superior limbus

Complications

1.

Operative – haemorrhage, button hole of the conjunctiva

2.

Postoperative – retraction of the conjunctival flap infection

Follow up and postoperative care

1.

Topical antibiotics and topical inflammatory treatment

2.

The inflammation gradually settles after a few weeks and the flap

continues to thin over several months

3.

Review at one day, one week, then as required

Indications

1.

Corneal perforation which has failed to respond to other modalities

of treatment

2.

Chronic epithelial defect which has failed to respond to conventional

medical therapy

Setting

1. Operating room

Equipment required

1.

Speculum

5. Plain forceps

2.

4.0 silk sutures

6. 10.0 nylon sutures

3.

Bard Parker no. 15 blade

7. Needle holder

4.

Conjunctival scissors

Anaesthesia

1.

Regional – local infiltration, peribulbar, subtenon

Procedure

1.

A single pedicle flap is created from conjunctiva adjacent to a corneal

lesion with the base at the insertion of one of the rectus muscles

2.

The corneal epithelium is debrided as previously described for

Gunderson’s flap

3.

The flap should be 20–30% larger than the area to be covered

4.

The conjunctiva is dissected from the tenons and the pedicle flap

placed on the cornea over the site that requires the flap and sutured

securely with 10.0 nylon sutures

Complications

1.

Operative – haemorrhage, avulsed flap, unable to close the defect

2.

Postoperative – infection, ischaemia of flap, persistent perforation

Follow up and postoperative care

Chloramphenicol 4/day for four days

Review at one day, one week, and then as required

PROCEDURES

Corneal biopsy

Indications

1.

Undiagnosed infections with negative smears and cultures

2.

Progressive keratitis with an infiltrate that is inaccessible to

corneal scraping

3.

Undiagnosed but significant corneal pathology, e.g. genetic metabolic

storage diseases, degenerations, dystrophies

Setting

1.

Slit lamp

2.

Operating room

Equipment required

1. Speculum

2.

Trephine (dermatological 2–3 mm)

3.

Sharp blade (preferably a diamond)

4.

Fine forceps

Anaesthesia

1.

Topical

2.

Regional – local infiltration, peribulbar, subtenon

Procedure

1.

Select the site for biopsy which should include a leading edge of the

lesion and a portion of uninvolved tissue

2.

Outline it with a trephine or blade up to a depth of 0.2–0.3 mm

followed by lamellar dissection of the area

3.

Place the specimen in a sterile container, moisten with BSS

Managing the specimen

1.

Infectious aetiology – divide the tissue into two for (a) histopathology

and (b) microbiology

2.

Non-infectious – divide the tissue into two for

(a) histopathology (buffered isotonic formalin) and

(b) electron microscopy (glutaraldehyde)

Complications

1.

Operative – iatrogenic corneal perforation

2.

Postoperative – secondary infection

Follow up and postoperative care

1.

Topical antibiotic and a cycloplegic agent until the epithelium covers

the biopsy site

2.

Review daily, then regularly until it heals, then as required

Indications

Recurrent erosion

Setting

Slit lamp

Equipment required

25 gauge needle

Anaesthesia

Topical

Procedure

1.

Identify unstable area.

2.

Multiple punctures (50–150) with 25 gauge needle

Complications

1.

Corneal ulceration

2.

Infection

Follow up and postoperative care

Pad/12 hours

Seven days, then as required

Indications

Infective keratitis

Setting

Slit lamp

Equipment required

1. Alcohol lamp

2.

Kimura spatula

3.

Glass slides

4.

Agar plates – blood agar

– chocolate agar

– Sabouraud’s agar

5.

Liquid media – special brain–heart infusion broth

– cooked meat medium

Anaesthesia

1.

Topical – non-preserved local anaesthetic preferred

– proparacaine hydrochloride (0.5%)

Procedure

1. Remove any adherent mucopurulent material

2.

The platinum spatula is used to collect specimens of corneal

scrapings at the slit lamp

3.

Multiple collections are made from the edge of the ulcer and from

the base

4.

One scraping is taken for each microbiological medium

5.

Allow 20 seconds for the tip of the spatula to cool between flaming

and scraping

6.

Material is inoculated onto the agar plates and into liquid media

7.

Transport the slides and media to the laboratory without delay

Managing the specimen

Material collected is distributed as follows.

1.

Gram/Giemsa staining

2.

Blood agar – incubated anaerobically at 35 C

3.

Chocolate agar – incubated in air 15% CO2 at 35 C

4.

Sabouraud’s agar – incubated in air at 28 C

5.

Special brain–heart infusion broth – incubated in air 15% CO2

at 35 C

6.

Cooked meat medium – incubated anaerobically at 35 C

Complications

1.

Operative – iatrogenic corneal perforation

2.

Postoperative – negative results

Follow up and postoperative care

First review no later than 24 hours

Indications

1.

Visual – keratoconus, dystrophy, scarring

2.

Pain – bullous keratopathy

3.

Tectonic – perforation, threatened perforation

Setting

Operating room

Equipment required

1.

Corneal graft set

2.

Speculum, SR/IR forceps, diamond knife or equivalent, micro tissue

holding forceps, tying forceps, needle holder, range of trephines, small

bore cannula, 6.0 silk on a spatulated needle (4 crossover retaining

sutures), 4.0 silk, 10.0 nylon

Anaesthesia

1.

Regional – local infiltration, peribulbar

2.

General anaesthesia

Procedure

Superior rectus and inferior rectus suture

1.

Posture globe. Eye and microscope to be coaxial

2.

Paracentesis, crossover sutures

3.

Cut recipient disc with trephine, blade, scissors. Often 7.5 mm

4.

Cut donor: punch donor eye on block, 0.25 mm oversize

5.

Place donor disc in defect, tie crossover sutures

6.

Place cardinal sutures 10.0 nylon at 6, 12, 3, and 9 o’clock

7.

Continuous 10.0 nylon or 16 10.0 nylon interrupted sutures

8.

BSS to a/c to check for leaks

Managing the specimen

Into isotonic buffered formaldehyde

Complications

1.

Operative – haemorrhage, damage to iris or lens

2.

Postoperative – infection, primary graft failure, astigmatism, allograft

rejection, elevated intraocular pressure, cataract

Follow up and postoperative care

1.

One day, one week, three weeks, six weeks, 12 weeks, six months,

nine months, 12 months, then annually

2.

Sutures removed at 12 months

Indications

Visual: corneal opacity where an optical iridectomy is not likely to be

useful

Setting

Operating room

Equipment required

Corneal graft set

Anaesthesia

General anaesthesia

Procedure

1.

Superior and inferior rectus suture to posture eye coaxial with

microscope. Positioning is sometimes required to expose entire cornea

2.

Corneoscleral support ring, crossover sutures, paracentesis

3.

Determine optimal size, usually 5–6 mm

4.

Cut donor, punch from endothelial surface with 1 mm oversize

5.

Excise recipient cornea with trephine, blade, scissors

6.

Place donor disc in recipient defect and secure by tying crossovers

and placing cardinal sutures at 3, 6, 9, and 12 o’clock

7.

Place 16 10.0 nylon interrupted sutures

8.

Balanced salt to anterior chamber

Managing the specimen

Divide in two. One half into buffered isotonic formaldehyde, one half

into glutaraldehyde for histopathology and electron microscopy

Complications

1.

Operative – haemorrhage, damage to iris or lens

2.

Postoperative – infection, primary graft failure, astigmatism,

allograft rejection, elevated intraocular pressure, cataract

Special consideration

It is helpful to administer an appropriate paediatric dose of an osmotic

agent (e.g. mannitol) at the beginning of the procedure to reduce

vitreous pressure

Follow up and postoperative care

1.

One day, one week, three weeks, then as required

2.

Suture removal: usually remove half sutures at six weeks, then other

half three weeks later