The discovery of systemic disease related to raised tissue and serum immunoglobulin G4 (IgG4) is changing diagnostic and therapeutic practice in many medical specialties.

Tetracyclines have an anticollagenolytic action in addition to their antimicrobial activity. The use of doxycycline as an adjunctive therapy in the management of Pseudomonas corneal melting may help to stabilize corneal breakdown and prevent subsequent perforation.

Fluoroquinolone antibiotic drops have been extensively used in bacterial keratitis because of their ease of availability, broad spectrum of activity, and lack of toxicity. While corneal precipitates have been reported with cases of topical ciprofloxacin and norfloxacin, little has been documented on corneal deposits and topical ofloxacin in the treatment of bacterial keratitis. The predisposing factors resulting in corneal deposits and the role of polypharmacy are important features that may impair epithelialisation. Clinical management should be aimed at reducing the toxic environment and promoting ocular surface stability.

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Penetrating keratoplasty is infrequently performed in the mentally retarded due to the high risk of serious post-operative complications, in particular wound rupture and severe inflammation of the graft. Graft survival is hindered by the patient's tendency for eye rubbing and possibly self-inflicted injury. Adequate nursing support is essential to ensure strict compliance with post-operative treatment. A retrospective study of corneal graft outcomes in mentally retarded patients was undertaken to assess graft survival, visual rehabilitation, post-operative complications and the influence on social behaviour. Six cases of penetrating keratoplasty performed in mentally retarded patients by one surgeon are presented. A continuous 10-0 nylon suture was employed in all cases. In 2 cases surgery was undertaken following perforation of the globe in patients with Down's syndrome. The grafts were retained in all cases and 2 patients achieved reasonably good acuity, although formal visual acuity assessment in these patients is limited. Penetrating keratoplasty in mentally retarded patients is a potentially hazardous procedure and patients require close supervision and good support care. This series demonstrates that relatively successful outcomes can be obtained in some mentally retarded patients.

Although bilateral Acanthamoeba keratitis is rare, it is essential that the patient is properly educated in contact lens hygiene and disinfection. Regular contact lens follow-up of patients is essential, and lens storage and disinfection techniques must be reviewed with the patient. The use of single-use contact lens storage cases may be advantageous in reducing the incidence of bilateral disease after case contamination.

Cockayne's syndrome is a rare, autosomal recessive condition which usually presents in early childhood, and is characterised by dwarfism, premature ageing, mental retardation and a typical facial appearance and body habitus. Retinal dystrophy, enophthalmos, strab ismus, cataract, nystagmus and corneal opacities are associated ocular features. At a genetic level, a defect occurs in the pathway for the repair of transcriptionally active DNA, and the most common form of Cockayne's is associated with mutations in the human repair gene ERCC6. These patients pose a difficult management problem. A significant proportion will require cataract extraction at an early age, which may present technical difficulties due to enophthalmos, which is a constant finding, poor pupillary dilation and growth retardation. Also, the fitting and assessment of aphakic contact lenses during the post-operative period requires great skill. General anaesthesia in these patients may be hazardous. In particular, difficulty with endotracheal intubation should be anticipated. Two patients with Cockayne's syndrome requiring bilateral cataract extraction in early infancy are presented. The problems associated with surgery, anaesthesia and subsequent follow-up in these mentally retarded infants are discussed. Cockayne's syndrome (CS) l is a rare autosomal recessive condition which presents in early childhood with growth failure, developmental delay and mental retardation? Patients have a characteristic facial appearance often associated with microcephaly. Erythematous rashes due to photosensitivity are common and the skin may appear prematurely aged, being dry and scaly. The limbs are dispropor tionately long with flexion contractures, and kypho scoliosis may develop. Neurological associations

Combining cataract extraction with posterior chamber IOL implantation and vitrectomy in one procedure may be indicated, especially if there is traumatic rupture of the lens capsule.