The presence of the parasite Demodex folliculorum on the skin surface of the eyelid

It is well established that Demodectic mites can infest the meibomian glands, eyelash and hair follicles of the eyelid. In this study, scanning electron microscopy revealed Demodex folliculorum occurring freely on the skin surface of the eyelid. This indicates some mobility and implies further vector potential. Exoskeletons from these parasites also occur on the eyelid.     

Moving muscles with microchips, mathematics and models: an update on the 'reverse' model

This paper reviews the current status of our computer model for the management of strabismus and its future direction. Vector analysis was first used in the 1950s for the assessment of strabismus. Robinson's model' was the first computer simulation of ocular motility. Using physiological principles and anatomical approximations, Robinson's model sought to predict the strabismic pattern to be expected from a given injury. The Kault/Stark 'reverse' model works in the opposite direction, to first simulate the given strabismic pattern and then advise the surgery required to restore orthophoria. The surgeon is able to 'trial' various operations and compare the expected postoperative results. An automated system is currently being developed to ease the difficulty in measuring the position of the eyes in all nine positions of gaze. This paper includes three illustrative case reports.     

ORBITAL CELLULITE AND PRESEPTAL CELLULITE IN CHILDHOOD

A study was made of 112 children with preseptal cellulitis, orbital cellulitis, subperiosteal abscess, and orbital abscess. These were consecutive admissions to the Royal Alexandra Hospital for Children, Sydney, during the period June 1976 to August 1985. The average age was 3 years 6 months. The clinical and radiological signs for each group were defined.
Of the 112 children, 43.8% (with an average age of 3 years 3 months) had a clinical history of an upper respiratory tract infection. Trauma was a factor in 13.4% of patients.
Haemophilus influenzae was recovered from blood culture in two patients and from conjunctival culture in seven patients. The average age of this group was 3 years 7 months.
Plain radiographs taken of 53 patients revealed evidence of paranasal sinus disease in 29 (54.7%). Computerized tomography was performed in 14 patients.
Of seven patients requiring surgical drainage of orbital or subperiosteal abscess (average age 7 years 2 months), five had clinical upper respiratory tract infection.     

The place of trabeculectomy in the management of primary open-angle glaucoma and factors favouring success

Medical treatment has always been the mainstay in the management of primary open-angle glaucoma (POAG). Surgical intervention has been reserved for cases with intraocular pressures uncontrolled on medical therapy and/or progression of visual field loss. Following the introduction of trabeculectomy, there was a move toward earlier surgery in POAG with some advocating it as a primary procedure. However, others have emphasised the cornplications and unpredictability of trabeculectomy and use it only as a last resort. In this article the literature is reviewed and the factors that prevent complications and help ensure a successful result in trabeculectomy are considered. While the role of trabeculectomy as a primary procedure in POAG is debatable, the authors favour earlier surgical intervention rather than using surgery as a last resort.     

Management of fixed divergent squint in third nerve palsy using traction sutures

Background: Long-standing fixed divergent squint is a difficult management problem, presenting marked cosmetic and functional symptoms in the patient, and a significant challenge for the squint surgeon to overcome.
Methods: We describe use of through-the-lid traction sutures in 24 consecutive patients with fixed divergent squint secondary to long-standing third nerve palsy. Very large recessions of the lateral rectus were combined with large resections of the medial rectus and traction sutures placed through the insertions of the superior and inferior rectus were brought out through the extreme medial for-nices and skin of the upper and lower lids. Sutures were tied overtarsorrhaphy bolsters and left in situ for six weeks.
Results: After removal of the traction sutures, the eye maintained a good cosmetic position in all but two cases. Postoperative motility was extremely limited or absent. Complications were limited to transient skin ulceration in two cases.
Conclusions: Supramaximal horizontal recess-resect procedure combined with adducting traction sutures left in situ for six weeks is a safe and effective procedure to restore the eye to the centre of the palpebral fissure.     

Keratoprosthesis: preliminary results of an artificial corneal button as a full-thickness implant in the rabbit model

Purpose: To develop a prototype artificial cornea and evaluate it in the rabbit model.
Methods: Hydrogel core-and-skirt keratoprostheses were made and were inserted as full-thickness implants covered with conjunctival flaps in the right eyes of eight rabbits.
Results: Peroperative complications related to inadequate mechanical strength led to failure in the early postoperative period in three animals, one was euthanased for an unrelated reason and the remaining four have been successful for up to 16 weeks' follow-up.
Conclusions: Full-thickness implantation of an artificial cornea; analogous to penetrating keratoplasty, has been achieved in the rabbit model. Histological findings confirm that integration of the prosthesis with host tissue occurs. The main complications encountered in this preliminary series were related to inadequate strength of the sponge skirt of this prototype device. Work in our laboratories is now concentrated upon improving the mechanical qualities of the hydrogel skirt and on the enhancement of biointegration.     

Corneal scarring and irregular astigmatism following refractive surgery in a corneal transplant

Background: Scarring may follow refractive surgery, causing irregular astigmatism and loss of visual acuity. Methods: A case report of scarring and irregular astigmatism occurring in a corneal transplant following photorefractive keratectomy and arcuate incisions is presented. Results: Following surgical excision of the scan unaided visual acuity improved from 1/60 to 6/12. Histopathology of the excised scar was obtained. Conclusions: Refractive surgery following corneal transplantation may produce scarring. The origin of the scar in the present case has not been established.     

Branch retinal artery occlusion in a child

Background: Retinal artery occlusive events are unusual in the paediatric population. The average age of their occurence is 60 years and the aetiology most often related to cardiovascular disease.
Case Report: A healthy 11-year-old white girl developed permanent unilateral visual field loss as a result of a branch retinal artery occlusion. An extensive work-up included transthoracic and transoesophageal echocardiograms, routine haematological and biochemical testing including serum lipids, screening for thrombophilia and thrombolysis, as well as autoantibodies, all of which proved to be within normal limits.
Conclusions: Recognition of the underlying aetiology is not always possible, but should be sought as prognosis for vision or survival may rest upon these findings.