Ординатура / Офтальмология / Английские материалы / Moorfields Manual of Ophthalmology_Jackson_2007

Pseudoexfoliation Syndrome

Background Pseudoexfoliation syndrome (PXS) is characterized by the deposition of grey flecks of amyloid-like fibrillar material on the lens capsule and many extraocular tissues. It is more common with increasing age, with geographical and racial clustering. Associated trabecular dysfunction may cause elevated IOP and pseudoexfolative glaucoma (PXG).

Symptoms May be an incidental finding or present late with glaucomatous field loss. Two-thirds are unilateral on presentation.

Signs Radial lens–iris contact may rub off pseudoexfolation (PXF) material leaving a ‘bull’s-eye’ pattern (a clear intermediate zone). Central iris transillumination occurs due to abrasion of iris pigment epithelium, and PXF material may be seen on the iris and pupil margin (Fig. 7.15). Gonioscopy shows ‘salt and pepper’ pigmentation on the trabecular meshwork and pigment deposition anterior to Schwalbe’s line (Sampaolesi line ). The pupil often dilates poorly.

History and examination Record family history, VA, IOP, iris transillumination, gonioscopy, RAPD, and disc examination (with pupils dilated). Note cataract density and postdilation pupil size. Look for phacodonesis – lens subluxation may occur due to weak zonules.

Investigations Arrange baseline disc imaging and visual fields. Further investigations are not routinely required.

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Pseudoexfoliation syndrome

Treatment Manage ocular hypertension and glaucomatous optic neuropathy as for primary open angle glaucoma (p. 287). Argon laser trabeculoplasty may be effective but may also fail abruptly. Routine trabeculectomy is usually effective. Cataract surgery may be complicated (≈fivefold increase in vitrectomy rate) due to weak zonules and small pupils, so manage accordingly

(p. 254). Postoperative capsule phimosis may be significant.

Follow–up With PXF only (no glaucomatous optic neuropathy or ocular hypertension), review 12 monthly. For PXG, review 3–12 monthly as indicated by the stability of IOP, disc, and field.

Pigment Dispersion Syndrome

Background Pigment dispersion syndrome (PDS) is characterized by pigment shedding from iris pigment epithelium and deposition on other intraocular structures. It is more common in Caucasians, myopes, and the 35–50 age group, and can occur with an autosomal dominant inheritance pattern with variable penetrance. Posterior bowing of the midperipheral iris results in abrasion of the iris by lens zonules. Pigment deposits in the trabecular meshwork are associated with raised IOP and glaucoma.

Symptoms Transient visual blurring or halos often following physical exertion. May present late with glaucomatous field loss.

Signs Pigment loss results in iris transillumination, typically seen as radial spokes in the midperiphery (Fig. 7.16). Pigment deposition on the corneal endothelium is usually concentrated in the vertical midline by aqueous convection (Krukenburg spindle). The anterior chamber is deep. Gonioscopy shows diffuse pigment deposition around 360º of the trabecular meshwork. The angle is

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Pigment dispersion syndrome

open and the peripheral iris may be appreciably bowed posteriorly. Pigment granules may be seen on the iris surface and among zonular insertions at the lens equator (Scheie stripe).

Differential diagnosis Angle pigmentation can occur in angle closure, and following trauma, iritis, and in pseudoexfoliation. Iritis may cause iris transillumination.

History and examination Ask about visual disturbance, particularly following exercise. Record family history, VA, IOP, corneal pigment deposits, anterior chamber depth and cellular activity, iris transillumination, gonioscopy, RAPD, and disc examination (with pupils dilated). Exclude peripheral retinal holes, especially if prescribing pilocarpine.

Investigations Request a baseline disc image and visual field.

Treatment Consider IOP measurement following exercise. Pigment dispersion may ‘burn out’ prior to causing elevated IOP. Iris–zonule contact may be reduced by low-dose pilocarpine, but this is often not tolerated. Treatment with laser peripheral iridotomy is controversial. Manage pigmentary glaucoma as for primary open angle glaucoma (p. 287). Argon laser trabeculoplasty may be effective but has a high failure rate; use low-power settings. Trabeculectomy is often effective.

Follow–up With PDS only (no glaucomatous optic neuropathy or ocular hypertension), review 6–12 monthly; for pigmentary glaucoma, 3–12 monthly as indicated by stability of the IOP, disc and fields.

Neovascular Glaucoma

Background A secondary glaucoma with open angle and angle-closure mechanisms resulting from iris neovascularization.

Symptoms Redness, pain, photophobia and decreased VA.

Signs Poor VA, high IOP, conjunctival congestion, corneal oedema, iris new vessels (NVI or rubeosis iridis), ectropion uveae, vessels crossing trabecular meshwork on gonioscopy, and peripheral anterior synechiae (PAS). Rubeosis iridis is shown on page 440.

Differential diagnosis For the causes of rubeosis iridis, see page 440.

Investigations Fluorescein angiography is not usually necessary. Arrange Carotid Doppler if relevant.

Treatment

■Control IOP : as shown in the treatment algorithm (Fig. 7.17). Arrange physician review as required.

■Urgent panretinal photocoagulation (PRP): using slit lamp, indirect, or endolaser. For technique see page 434. Consider cryotherapy or trans-scleral diode laser retinal ablation if an inadequate fundal view prevents laser treatment under direct vision.

■Medical treatment : topical glaucoma medication is required in eyes with navigational vision or better. If the eye is painful with no useful navigational vision, manage with G. dexamethasone 0.1% q.d.s., G. atropine 1% b.d.

■Surgical treatment : for eyes with good potential visual function, consider glaucoma drainage devices (GDD), or mitomycin C (MMC) augmented trabeculectomy only if the eye is uninflamed.

■Ciliary ablation by diode laser: see page 298.

■Retrobulbar alcohol or enucleation : reserved for painful blind eyes not controlled medically or with cyclodestruction.

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Neovascular glaucoma

Fig. 7.17: Neovascular glaucoma treatment algorithm.

Uveitic Glaucoma

Background Ten percent of uveitic eyes develop secondary glaucoma.

Signs Look for keratic precipitates, flare, iris atrophy/nodules, and posterior synechiae. Gonioscopy may show peripheral anterior synechiae, pigment, or debris in the angle.

Management Problems include frequent recurrence, variable IOP, pupillary membranes and secondary cataracts precluding disc assessment and reliable field testing, and the need for long-term steroid treatment. Collaborate with uveitis specialists and physicians, especially for immunosuppression. Treatment depends on the mechanism(s):

■Secondary open angle glaucoma : treat medically and control the uveitis.

■Closed angle glaucoma with pupil block : examine the other eye to rule out primary angle closure. Treat as acute angle closure but without miotics. Surgical iridectomy is preferable to laser.

■Steroid pressure response : see next page.

■Closed angle without pupil block : medical management of IOP.

■All mechanisms : if medical therapy fails, consider mitomycin C-augmented trabeculectomy. Do not combine cataract and filtering surgery. Use postoperative steroids and 5FU judiciously, using the minimum steroid potency and dosage. If enhanced filtration surgery fails then consider drainage tubes.

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Steroid pressure response and associated glaucoma

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Steroid Pressure Response and

Associated Glaucoma

Background Usually caused by topical steroids, especially prednisolone and dexamethasone, but may be caused by intraocular, periocular, inhaled, intranasal, or systemic steroids. G. dexamaethasone 0.1% q.d.s. for 6 weeks is associated with an IOP rise of >6 mmHg in 35% of normal adults versus 95% of patients with primary open angle glaucoma (POAG). Higher IOP rises occur in POAG patients and their first-degree relatives.

Classification Low response (<6 mmHg IOP rise); intermediate response (6–15 mmHg); and high response

(>15 mmHg). Diagnosis is confirmed by IOP fall on steroid reduction.

Symptoms Often asymptomatic unless there is advanced field loss or very high IOP.

Signs Raised IOP, usually after 4–6 weeks of steroids (rarely before 2 weeks, except in children). Optic disc cupping with visual field loss may suggest steroid-induced glaucoma.

History and examination Record the steroids used, their concentration, frequency and duration, IOP, and optic disc assessment. Perform gonioscopy. Exclude posterior subcapsular cataract.

Differential diagnosis Undiagnosed or coexisting ocular hypertension / POAG.

Investigations Disc imaging and visual field assessment.

Treatment See Box 7.4

Follow–up The rate of IOP fall is variable (days to months). Occasionally, IOP rise is permanent.

Box 7.4: Treatment of steroid pressure response and associated glaucoma

■Reduce the potency and frequency of steroid treatment.

■Consider fluorometholone or rimexolone (less steroid response in adults).

■Treatment as for POAG if IOP remains above target (p. 287).

■Consider topical NSAIDs for the management of inflammation.

Phacolytic and

Phacomorphic Glaucoma

Background Disease of the lens may cause raised IOP. Identifying the underlying mechanism is important before deciding on the appropriate therapeutic options.

Classification

■Phacolytic : leakage of protein from mature or hypermature cataract through an intact capsule obstructing trabecular meshwork.

■Phacomorphic : secondary angle closure from lens intumescence. Increases relative pupil block.

Symptoms Unilateral pain, reduced VA, lacrimation, and photophobia.

Signs Intumescent mature or hypermature (Morganian) cataract, conjunctival hyperaemia, corneal oedema, and IOP >21 mmHg. Note VA.

History Record duration and severity of symptoms, previous history of cataracts, ocular surgery or uveitis.

Examination

■Phacolytic : angles open on gonioscopy, intense anterior chamber flare with small white particles of lens matter.

■Phacomorphic : closed angles on gonioscopy, shallow anterior chamber, typically with contralateral eye showing deeper anterior chamber and open angles.

Differential diagnosis

■Symptomatic primary angle closure : characteristically has symmetrically narrow angles. A mature/hypermature cataract is not present.

■Inflammatory/uveitic glaucoma : exclude other uveitides by thorough examination.

■Phacoanaphylactic glaucoma : granulomatous uveitis with keratic precipitates and hypopyon is usual, with a history of cataract surgery.

Investigations B-scan ultrasonography (±ultrasound biomicroscopy [UBM]) is useful in defining the anatomical relationships and excluding retrolental disease. Record axial length, AC depth, lens thickness, or PC configuration in both eyes.

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Phacolytic and phacomorphic glaucoma

Box 7.5: Phacolytic and phacomorphic glaucoma treatment

■Topical beta blockers (e.g. timolol 0.25% b.d.,), and/or topical alpha agonist (e.g. apraclonidine 0.5% t.d.s.).

■Oral carbonic anhydrase inhibitors (e.g. acetazolamide 500 mg stat dose, then 250 mg q.d.s).

■Topical steroid (e.g. prednisolone 1% 2-hourly).

■Cycloplegics (e.g. cyclopentolate 1% t.d.s.).

Treatment The immediate aim is to control IOP and inflammation (Box 7.5).

Hyperosmotic agents (e.g oral glycerol 50% 1 ml/kg) may be necessary. Miotics must be avoided, since they may shift the iris– lens diaphragm forward, exacerbating angle closure, and possibly increase inflammation. The definitive treatment is cataract extraction as soon as IOP and inflammation are controlled.