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

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2Systemic features include severe deafness, dental anomalies, multiple fractures (Fig. 8.17B) and short limbs; death in early infancy from respiratory infection.

3Ocular manifestations include blue sclera and shallow orbits.

Ehlers–Danlos syndrome type VI

Ehlers–Danlos syndrome VI (ocular sclerotic) is a rare, usually AR disorder of collagen caused by deficiency of procollagen lysyl hydroxylase. There are nine distinct subtypes but type 6 and, rarely, type 4, are associated with ocular features.

1Skin is thin and hyperelastic (Fig. 8.18A). It bruises easily, heals slowly and with a tendency to ‘papyraceous’ scarring (Fig. 8.18B).

2Joints are hypermobile with lax ligaments (Fig. 8.18C). This may lead to recurrent dislocation, repeated falls, hydroarthrosis and pseudotumour formation over the knees and elbows.

3Cardiovascular disease consists of a bleeding diathesis, dissecting aneurysms, spontaneous rupture of large blood vessels and mitral valve prolapse.

4Other systemic manifestations include scoliosis, diaphragmatic hernias, and diverticula of the gastrointestinal and respiratory tracts.

5Other ocular features include scleral fragility with globe rupture caused by mild trauma, epicanthic folds, microcornea, keratoconus, keratoglobus, ectopia lentis, myopia and retinal detachment.

Fig. 8.18 Ehlers–Danlos syndrome type VI. (A) Cutaneous hyperelasticity; (B) papyraceous scarring; (C) joint hypermobility

(Courtesy of MA Mir, from Atlas of Clinical Diagnosis, Saunders, 2003 – figs A and B; JH Krachmer, MJ Mannis and EJ Holland, from Cornea, Elsevier 2005 – fig. C)

Other systemic associations

1Marshall–Smith syndrome is characterized by accelerated prenatal skeletal maturation and growth, broad middle phalanges, mental handicap, umbilical hernia and shallow orbits.

2Russell–Silver syndrome is characterized by short stature, small triangular face, fasting hypoglycemia in early infancy, and limb asymmetry.

3Hallermann–Streiff–François syndrome (see Ch. 9).

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Miscellaneous conditions

Congenital ocular melanocytosis

Classification

Congenital ocular melanocytosis is an uncommon condition characterized by an increase in number, size and pigmentation of melanocytes (Fig. 8.19A) in the sclera and uvea and may also involve the periocular skin, orbit, meninges and soft palate. It occurs in the following three clinical settings.

1Ocular melanocytosis, the least common, involves only the eye.

2Dermal melanocytosis involves only the skin and accounts for about one-third of cases.

3Oculodermal melanocytosis (naevus of Ota) is the most frequent type and involves both skin and eye.

Fig. 8.19 Congenital melanocytosis. (A) Histology shows an increase in the number, size and pigmentation of melonocytes in the inner sclera and choroid; (B) episcleral melanocytosis; (C) cutaneous melanocytosis

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

Clinical features

1Signs

•Multifocal slate-grey pigmentation within the sclera and episclera which cannot be moved over the globe (Fig. 8.19B).

•Occasionally the peripheral cornea may be involved.

2 Naevus of Ota is bilateral in 5% of patients, occurring frequently in Orientals and darker races but rarely in Caucasians.

•Deep bluish hyperpigmentation of facial skin, most frequently in the distribution of the 1st and 2nd divisions of the trigeminal nerve (Fig. 8.19C).

•It may be subtle in fair-skinned individuals and is best detected by observation in good lighting.

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•Involvement of the 3rd division of the trigeminal nerve and of the nasal and buccal mucosa is uncommon.

Ipsilateral associations

1Iris hyperchromia is common (Fig. 8.20A).

2Iris mammillations, which are tiny, regularly spaced, villiform lesions, are uncommon (Fig. 8.20B). They may also be found in patients with neurofibromatosis type 1, Axenfeld–Rieger anomaly and Peters anomaly.

3Fundus hyperpigmentation can occur (Fig. 8.20C).

4 Trabecular hyperpigmentation (Fig. 8.20D) which is associated with glaucoma in about 10% of cases.

5Uveal melanoma may develop in a small minority of patients, and long-term review is required.

Fig. 8.20 Ipsilateral associations of naevus of Ota. (A) Iris heterochromia; (B) iris mammillations; (C) fundus hyperpigmentation; (D) trabecular hyperpigmentation

(Courtesy of B Gilli – fig. A; L MacKeen – fig. D)

Idiopathic sclerochoroidal calcification

Idiopathic sclerochoroidal calcification is an innocuous, age-related condition that is usually bilateral.

1Signs. A yellow-white choroidal mass with ill-defined margins located in the superotemporal (Fig. 8.21A) or inferotemporal midperiphery.

2Ultrasonogram shows a highly reflective choroidal plaque-like lesion with orbital shadowing (Fig. 8.21B).

3Differential diagnosis includes choroidal metastatic tumour, amelanotic choroidal melanoma, choroidal naevus and choroidal osteoma.

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Fig. 8.21 (A) Idiopathic sclerochoroidal calcification; (B) ultrasonogramshows a highly reflective lesion with orbital shadowing

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

Scleral hyaline plaque

Scleral hyaline plaques are bilateral oval, dark-greyish areas located close to the insertion of the horizontal rectus muscles (Fig. 8.22) that should not be confused with scleromalacia perforans. They typically affect elderly patients and are entirely innocuous.

Fig. 8.22 Scleral hyaline plaque

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Chapter 9 – Lens

ACQUIRED CATARACT 270 Age-related cataract 270 Cataract in systemic diseases  272

Secondary cataract 273 Traumatic cataract 273

MANAGEMENT OF AGE-RELATED CATARACT 273 Preoperative considerations 273

Intraocular lenses 279 Anaesthesia 280 Phacoemulsification 281

Small incision manual cataract surgery 285 Operative complications 285

Acute postoperative endophthalmitis 289 Delayed-onset postoperative endophthalmitis  293

Posterior capsular opacification 295

Anterior capsular fibrosis and contraction 296 Miscellaneous postoperative complications 296

CONGENITAL CATARACT 298 Aetiology 298 Inheritance 298 Morphology 298

Systemic metabolic associations 298 Associated intrauterine infections 302 Associated chromosomal abnormalities  302

Associated skeletal syndromes 302 Management 303

ECTOPIA LENTIS 304

Without systemic associations  304

With systemic associations 304 Management 307

ABNORMALITIES OF SHAPE 308 Anterior lenticonus 308 Posterior lenticonus

 308

Lentiglobus 309

Microspherophakia 309

Microphakia 309

Coloboma 309

Acquired cataract

Age-related cataract

Subcapsular cataract

Anterior subcapsular cataract lies directly under the lens capsule and is associated with fibrous metaplasia of the lens epithelium. Posterior subcapsular opacity lies just in front of the posterior capsule and has a vacuolated, granular, or plaque-like appearance on oblique slit-lamp biomicroscopy (Fig. 9.1A) and appears black on retroillumination (Fig. 9.1B). Due to its location at the nodal point of the eye, a posterior subcapsular opacity has a more profound effect on vision than a comparable nuclear or cortical cataract. Near vision is frequently impaired more than distance vision. Patients are particularly troubled under conditions of miosis, such as produced by headlights of oncoming cars and bright sunlight.

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Fig. 9.1 Age-related cataract. (A) Posterior subcapsular; (B) on retroillumination; (C) nuclear; (D) on retroillumination

(Courtesy of J Schuman, V Christopoulos, D Dhaliwal, M Kahook and R Noecker, from Lens and Glaucoma, in Rapid Diagnosis in Ophthalmology, Mosby 2008 – figs A-C)

Nuclear cataract

Nuclear cataract starts as an exaggeration of the normal ageing changes involving the lens nucleus. It is often associated with myopia due to an increase in the refractive index of the nucleus, and also with increased spherical aberration. Some elderly patients may consequently be able to read without spectacles again ('second sight of the aged’). Nuclear sclerosis is characterized in its early stages by a yellowish hue due to the deposition of urochrome pigment. This type of cataract is best assessed with oblique slit-lamp biomicroscopy (Fig. 9.1C) and not by retroillumination (Fig. 9.1D). When advanced the nucleus appears brown.

Cortical cataract

Cortical cataract may involve the anterior, posterior or equatorial cortex. The opacities start as clefts and vacuoles between lens fibres due to hydration of the cortex. Subsequent opacification results in typical cuneiform (wedge-shaped) or radial spoke-like opacities, often initially in the inferonasal quadrant (Fig. 9.2A and B). Patients with cortical opacities frequently complain of glare due to light scattering.

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Fig. 9.2 Age-related cataract (A) Cortical; (B) on retroillumination; (C) Christmas tree; (D) on retroillumination

(Courtesy of J Schuman, V Christopoulos, D Dhaliwal, M Kahook and R Noecker, from Lens and Glaucoma, in Rapid Diagnosis in Ophthalmology, Mosby 2008 – figs A and B)

Christmas tree cataract

Christmas tree cataract, which is uncommon, is characterized by striking polychromatic needle-like deposits in the deep cortex and nucleus (Fig. 9.2C and D); they may be solitary or associated with other opacities.

Cataract maturity

1Immature cataract is one in which the lens is partially opaque.

2 Mature cataract is one in which the lens is completely opaque (Fig. 9.3A).

3Hypermature cataract has a shrunken and wrinkled anterior capsule due to leakage of water out of the lens (Fig. 9.3B).

4Morgagnian cataract is a hypermature cataract in which liquefaction of the cortex has allowed the nucleus to sink inferiorly (Fig. 9.3C and D).

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Fig. 9.3 Cataract maturity. (A) Mature cataract; (B) hypermature cataract with wrinkling of the anterior capsule; (C) Morgagnian cataract with liquefaction of the cortex and inferior sinking of the nucleus; (D) total liquefaction and absorption of the cortex with inferior sinking of the lens

(Courtesy of P Gili – fig. D)

Cataract in systemic diseases

Diabetes mellitus

Hyperglycaemia is reflected in a high level of glucose in the aqueous humour, which diffuses into the lens. Here glucose is metabolized by aldose reductase into sorbitol, which then accumulates within the lens, resulting in secondary osmotic overhydration of the lens substance. In mild degree, this may affect the refractive index of the lens with consequent fluctuation of refraction pari passu with the plasma glucose level (hyperglycaemia resulting in myopia and vice versa). Cortical fluid vacuoles develop and later evolve into frank opacities.

1Classic diabetic cataract, which is rare, consists of snowflake cortical opacities (Fig. 9.4A) occurring in the young diabetic. Such a cataract may resolve spontaneously or mature within a few days (Fig. 9.4B).

2 Age-related cataract occurs earlier in diabetes mellitus. Nuclear opacities are common and tend to progress rapidly.

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Fig. 9.4 Cataract in systemic disease. (A) Diabetic snowflake cataract; (B) advanced diabetic cataract; (C) stellate posterior subcapsular cataract in myotonic dystrophy; (D) advanced left cataract in a patient with myotonic dystrophy; (E) bilateral advanced cataracts in atopic dermatitis; (F) shield-like anterior subcapsular cataract in atopic dermatitis

(Courtesy of A Fielder – fig. A; J Schuman, V Christopoulos, D Dhaliwal, M Kahook and R Noecker, from Lens and Glaucoma, in Rapid Diagnosis in Ophthalmology, Mosby 2008 – fig. B; L Merin – fig. D)

Myotonic dystrophy

Myotonic dystrophy is an AD condition characterized by delayed muscular relaxation after cessation of voluntary effort (myotonia – see Ch. 19). About 90% of patients develop visually innocuous, fine cortical iridescent opacities in the 3rd decade which evolve into visually disabling stellate posterior subcapsular opacities (Fig. 9.4C) by the 5th decade that may progress to maturity (Fig. 9.4D); occasionally cataract may predate myotonia.

Atopic dermatitis

About 10% of patients with severe atopic dermatitis develop cataracts in the 2nd–4th decades; these are often bilateral and may mature quickly (Fig. 9.4E). Shield-like dense anterior subcapsular plaque which wrinkles the anterior capsule is characteristic (Fig. 9.4F). Posterior subcapsular opacities resembling a complicated cataract may also occur.

Neurofibromatosis type 2

NF2 (see Ch. 19) is associated with cataract in about 60% of patients. It tends to develop prior to the age of 30 years. They may be posterior subcapsular or capsular, cortical or mixed.

Secondary cataract

A secondary (complicated) cataract develops as a result of some other primary ocular disease.

Chronic anterior uveitis

Chronic anterior uveitis is the most common cause. The incidence is related to the duration and activity of intraocular inflammation that results in prolonged breakdown of the blood–aqueous and/or blood–vitreous barrier. The use of steroids, topically and systemically, is also important. The earliest finding is a polychromatic lustre at the posterior pole of the lens which may not progress if the uveitis is arrested. If the inflammation persists, posterior (Fig. 9.5A) and anterior opacities (Fig. 9.5B and C) develop that may progress to maturity. The opacities appear to progress more rapidly in the presence of posterior synechiae.

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