Ординатура / Офтальмология / Английские материалы / Clinical Ophthalmology A Systematic Approach 7th Edition_Kanski, Bowling_2011

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Age-related macular hole

Overview

Idiopathic age-related macular hole is a relatively common cause of central visual loss, with a prevalence of approximately 3 : 1000 individuals; with peak incidence of onset in females in the 7th decade. Presentation may be with impairment of central vision in one eye, or as a relatively asymptomatic deterioration, first noticed when the fellow eye is closed or at a routine sight test. The risk of involvement of the fellow eye at 5 years is around 10%.

Pathogenesis

The pathogenesis is incompletely defined, but current hypotheses suggest a role for the following:

•Oblique/anteroposterior traction via a persistent vitreofoveolar attachment following perifoveal vitreous separation.

•Tangential vitreoretinal traction.

•Predisposing involutional change of the inner retinal layers at the fovea.

Stages

1Stage 1a: ‘Impending’ macular hole

aSigns: flattening of the foveal depression with an underlying yellow spot.

bPathology: inner retinal layers (‘Müller cell cone’) detach from the underlying photoreceptor layer, with the formation of a schisis cavity.

2Stage 1b: Occult macular hole

aSigns: a yellow ring (Fig. 14.53A) that may be associated with metamorphopsia or a mild decrease in visual acuity.

bPathology: loss of structural support causes the photoreceptor layer to undergo centrifugal displacement (Fig. 14.54B).

3 Stage 2: Small full-thickness hole

aSigns: full-thickness hole less than 400 µm in diameter (Fig. 14.53B). The defect may be central, slightly eccentric or crescent-shaped.

bPathology: a dehiscence develops in the roof of the schitic cavity, often with persistent vitreofoveolar adhesion (Fig. 14.54C).

4Stage 3: Full-size macular hole

aSigns: full-thickness hole greater than 400 µm in diameter with a red base in which yellow-white dots may be seen. A surrounding grey cuff of subretinal fluid is usually present (Fig. 14.53C), and an overlying operculum (sometimes called a pseudo-operculum) may be visible. Visual acuity is often reduced to 6/60, although it is occasionally better, particularly in patients able to use eccentric fixation.

bPathology: avulsion of the roof of the cyst (Fig. 14.54D) with an operculum (Fig. 14.54E) and persistent parafoveal attachment of the vitreous cortex.

5 Stage 4: Full-size macular hole with complete PVD

aSigns: as above.

bPathology: the posterior vitreous is completely detached, often suggested (but not confirmed) by the presence of a Weiss ring.

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Fig. 14.53 Macular hole (A) Occult – stage 1b; (B) small full-thickness – stage 2; (C) full-sized – stage 3

(Courtesy of J Donald M Gass, from Stereoscopic Atlas of Macular Diseases, Mosby 1997 – fig. A; S Milenkov – fig. B)

Fig. 14.54 High resolution OCTof macular hole. (A) Normal; (B) stage 1b shows attachment of the posterior hyaloid to the fovea, separation of a small portion of the sensory retina fromthe RPEin the foveolar region and intraretinal cystic changes; (C) eccentric stage 2 shows attachment of the vitreous to the lid of the hole and cystic changes; (D) stage 3 shows a full-thickness hole with intraretinal cystic spaces at its border; (E) stage 4 shows a full-thickness macular hole with intraretinal cystic spaces and an overlying pseudooperculum; (F) stage 4 after surgical closure

(Courtesy of J Fujimoto)

Investigations

Slit-lamp biomicroscopy alone is usually sufficient to make the diagnosis.

1The Watzke–Allen test is performed by projecting a narrow slit beam over the centre of the hole both vertically and horizontally, preferably using a Goldmann fundus contact lens. A patient with a macular hole will report that the beam is thinned or broken. In contrast, patients with a pseudoor lamellar hole, or a cyst, usually see a distorted beam of uniform thickness.

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2OCT is extremely useful in the diagnosis and staging (see Fig. 14.54).

3FA in a full-thickness hole shows an early well-defined window defect due to xanthophyll displacement and RPE atrophy. Late frames may show the surrounding subretinal fluid as a hyperfluorescent halo (Fig. 14.55).

4Amsler grid testing will show non-specific central distortion rather than a scotoma.

Fig. 14.55 (A) Stage 4 macular hole; (B) FA shows corresponding hyperfluorescence

(Courtesy of S Milewski)

Surgery

About 50% of stage 1 holes resolve following spontaneous vitreofoveolar separation, so these are managed conservatively. About 10% of fullthickness holes also close spontaneously, with variable visual improvement.

1Indications are stage 2 or worse holes provided visual acuity is less than 6/9. Superior results are usually achieved in holes which have been present for less than 6 months, but substantial visual improvement has been reported in long-standing cases.

2Technique:

•Vitrectomy and peeling of the internal limiting membrane (ILM).

•Peeling is facilitated by staining the ILM with indocyanine green, trypan blue or triamcinolone. Although indocyanine green may be the most effective agent surgically, dose-related toxicity has been reported.

•Vitreomacular traction must be relieved, either by induction of a total PVD if not already present or by removal of the perifoveal vitreous.

•Gas tamponade is usual, but the necessity for strict extended postoperative face-down posturing (e.g. 50 minutes per hour for 7–14 days) is under review.

•Adjunctive agents such as autologous serum or platelets may be used.

•Because a cataract often develops following vitrectomy, combined surgery (‘phacovitrectomy’) may be considered.

3Results. The hole is closed in up to 100% of cases (Fig. 14.54F) and visual improvement occurs over the course of many months in 80–90% of eyes, with a final visual acuity of 6/12 or better in approximately 65%. Worsening of visual acuity occurs in up to 10% of eyes.

4Complications are essentially those of vitrectomy. Occasionally, the hole may enlarge. Visual field defects may develop secondary to prolonged intraoperative retinal exposure to dry air.

Differential diagnosis of age-related macular hole

1 Other causes of full-thickness macular hole

aHigh myopia in the presence of posterior staphyloma may be associated with macular hole formation which can lead to

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retinal detachment. The subretinal fluid is generally confined to the posterior pole.

bBlunt ocular trauma may cause a macular hole as a result of either vitreous traction or commotio retinae (see Ch. 21).

2Lesions with a similar appearance

aPseudohole in a macular epiretinal membrane.

bLamellar hole resulting from an abortive process of macular hole formation or in long-standing severe CMO (see Fig. 14.61).

c Foveal pseudocyst, typically idiopathic; in at least some patients may correspond to stage 1 macular hole. d Vitreomacular traction syndrome.

eSolar retinopathy.

fMacular microhole (see below).

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Macular microhole

Macular microhole is uncommon and may be easily overlooked without a careful history and examination. It is usually unilateral and has a favourable prognosis.

1Presentation is with minimal symptoms, usually a central scotoma or reduced reading vision.

2Signs. A very small, red, well-demarcated intraretinal foveal or juxtafoveal defect that remains stationary with long-term follow up (Fig. 14.56A).

3Higher-resolution OCT shows a well localized subtle defect gap in the photoreceptors and/or the RPE (Fig. 14.56B).

4Differential diagnosis includes stage 1a age-related macular hole, solar retinopathy and blunt trauma.

Fig. 14.56 Macular microhole. (A) Small red foveal lesion; (B) OCTshows a subtle defect in the sensory retina

(Courtesy of C Barry – fig. B)

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Central serous chorioretinopathy

Overview

Central serous chorioretinopathy (CSCR) is an idiopathic disorder characterized by a localized serous detachment of the sensory retina at the macula secondary to leakage from the choriocapillaris through focal, or less commonly diffuse, hyperpermeable RPE defects. CSCR typically affects one eye of a young or middle-aged Caucasian man; women with CSCR tend to be older. Imperfectly defined additional risk factors include psychological stress, type A personality, steroid administration, Cushing syndrome, systemic lupus erythematosus and pregnancy.

Clinical features

1Presentation is with unilateral metamorphopsia that may be associated with micropsia, mild dyschromatopsia and decreased contrast sensitivity.

2VA is usually reduced to 6/9–6/18, but often correctable to 6/6 with a weak convex lens, because elevation of the sensory retina gives rise to an acquired hypermetropia.

3Signs

•A round or oval detachment of the sensory retina is present at the macula (Fig. 14.57A).

•The subretinal fluid may be clear (particularly in early lesions), turbid or fibrinous, and precipitates may be present on the posterior retinal surface.

•One or more abnormal depigmented RPE foci (sometimes small PEDs) of variable size may be visible within the neurosensory detachment.

•Small patches of RPE atrophy and hyperplasia elsewhere in the posterior pole may indicate the site of previous lesions.

•The optic disc should be examined to exclude a congenital pit.

Fig. 14.57 (A) Central serous chorioretinopathy; (B) OCTshows separation of the sensory retina fromthe RPE

(Courtesy of C Barry – fig. B)

Investigations

1Amsler grid confirms metamorphopsia corresponding to the neurosensory detachment.

2 OCT shows an optically empty neurosensory elevation (Fig. 14.57B). A RPE detachment or a deficit in the RPE may also be seen. 3 FA may show the following patterns:

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•'Smokestack’ manifests as an early hyperfluorescent spot (Fig. 14.58A) that progresses to form a vertical column by the late venous phase (Fig. 14.58B), followed by diffusion throughout the detached area.

•‘Ink blot’ (most common) shows an early hyperfluorescent spot (Fig. 14.58C) that gradually enlarges (Fig. 14.58D).

•An underlying PED may be demonstrated.

•Multiple leakage points or diffuse leakage can be evident, particularly in chronic or recurrent disease.

4ICGA. The early phase may show dilated or compromised choroidal vessels at the posterior pole. The mid-stage shows areas of hyperfluorescence due to choroidal hyperpermeability.

Fig. 14.58 FA in central serous chorioretinopathy. (A and B) ‘Smokestack’ appearance; (C and D) ‘ink blot’ appearance

(Courtesy of S Milewski)

Course

1Spontaneous resolution occurs in most patients within 3–6 months, with return to near-normal or normal vision in more than 80% but recurrences occur in up to 50% of cases.

2Chronic course lasting more than 12 months constitutes a minority and typically affects older patients.

•Prolonged detachment is associated with gradual photoreceptor and RPE degeneration with resultant visual impairment.

•Multiple recurrent attacks may also give a similar clinical picture.

•FA shows granular hyperfluorescence with one or more leaks (Fig. 14.59).

•CMO, CNV or RPE tears may develop in a minority of cases.

3Bullous CSCR is characterized by large, single or multiple, serous retinal and RPE detachments that should not be misdiagnosed as rhegmatogenous retinal detachment or exudative detachment from another cause.

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Fig. 14.59 FA in chronic central serous chorioretinopathy. (A) Venous phase shows granular hyperfluorescence; (B) late stage shows fading of fluorescence

(Courtesy of Moorfields Eye Hospital)

Management

1Observation is appropriate in most cases.

2 Discontinue any corticosteroid treatment if possible, particularly in chronic, recurrent or severe cases.

3Lifestyle change to reduce stress in selected cases.

4Laser photocoagulation to the RPE leak speeds resolution but does not influence the final visual outcome or recurrence rate. It is advisable to wait at least 4 months before considering treatment of a first attack, and 1–2 months for recurrences. Thermal laser treatment is probably inadvisable if the leak is within the FAZ. Two or three low-intensity burns (200 µm, 0.2 second) are applied to the leakage site (Fig. 14.60) to produce mild greying of the RPE.

5PDT may be considered in subfoveal leaks or chronic disease. Only 30% of the dose of verteporfin used for CNV, in conjunction with 50% light intensity is used by some authorities as first-line treatment.

6 Intravitreal anti-VEGF agents show some promise.

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Fig. 14.60 Laser treatment of central serous chorioretinopathy. (A and B) Prior to treatment; (C and D) after successful treatment

(Courtesy of C Barry)

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Cystoid macular oedema

Pathogenesis

Cystoid macular oedema (CMO) results from the accumulation of fluid in the outer plexiform and inner nuclear layers of the retina with the formation of cyst-like changes (Fig 14.61A). Fluid may initially accumulate intracellularly in Müller cells, with subsequent rupture. In longstanding cases, smaller microcystic spaces coalesce into larger cavities and may progress to lamellar hole formation at the fovea (Fig.

14.61B) with irreversible impairment of central vision. CMO is a non-specific manifestation of any type of macular oedema.

Fig 14.61 Cystoid macular oedema. (A) Histology shows cystic spaces in the outer plexiformand inner nuclear layer; (B) progression to lamellar hole formation

(Courtesy of J Harry and G Misson, from Clinical Ophthalmic Pathology, Butterworth-Heinemann 2001 – fig. A)

Diagnosis

1Presentation is with blurring and distortion. There is typically pre-existing disease such as diabetes indicating the cause, although CMO may be the presenting feature of a causative condition such as branch retinal vein occlusion.

2Signs

•Loss of the foveal depression, thickening of the retina and multiple cystoid areas in the sensory retina (Fig. 14.62A), best seen with red-free light using a fundus contact lens (Fig. 14.62B).

•Optic disc swelling is sometimes present.

•A lamellar hole may be visible.

•Features of associated disease.

3 Amsler chart testing demonstrates central blurring and distortion.

4FA shows early hyperfluorescent spots due to leakage that progress to a characteristic petaloid pattern (Fig. 14.62C) of dye accumulation within microcystic spaces in the outer plexiform layer.

5OCT shows cyst-like hyporeflective spaces within the retina, with retinal thickening and loss of the foveal depression (Fig. 14.62D). It is effective in demonstrating vitreoretinal traction and the presence of a lamellar hole. Serial examination is commonly used to assess the response to treatment.

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