Bony orbital anatomy of the koala (Phascolarctos cinereus).

This is the first documented study of the anatomical details of the normal koala orbit. Baseline data are established which are necessary for understanding and treating ocular disease in the koala (Phascolarctos cinereus). The bony anatomy of the orbit of the koala was examined and described from animals that presented dead or had been euthanized for humane reasons. Dissections of the orbital cavity were performed under magnification, and descriptions of the orbital bones were from macerated skulls that had been boiled and cleaned. In general, the orbital bones of the koala, and their respective foramina, are consistent with those of other carnivorous polyprotodont and herbivorous diprotodont marsupials.

Intraorbital anatomy of the koala (Phascolarctos cinereus).

This is the first documented study of the anatomical details of the contents of the normal koala orbit, excluding the bulbus oculi. Baseline data were established which are necessary for understanding and treating ocular disease in the koala (Phascolarctos cinereus). The anatomy of the orbital contents of the koala were examined and described from animals that presented dead or were euthanized for humane reasons. Dissections of the orbital cavity were performed under magnification. Polymethyl methacrylate (PMMA) casts of the nasolacrimal system and the vascular supply of the orbit were also made in order to study these systems. The superficial lymphatic drainage of the conjunctival tissues was studied by subcutaneous injection of Evan's Blue into the palpebral conjunctiva of a freshly deceased animal, and by Microfil casts of the efferent lymphatics. In general, the orbital contents of the koala are consistent with those of other carnivorous polyprotodont and herbivorous diprotodont marsupials.

Corneal endothelial response to induced myopia in the chicken.

PURPOSE: To investigate the role of corneal endothelial surface enlargement in the chicken myopia model in inducing corneal endothelial changes. METHODS: Lid suture was performed on one eye of 1-day-old cockerels. Five chickens were killed at 1 week, and four chickens killed at each of 3 weeks, 6 weeks, and 10 weeks postnatal. The endothelial morphology was obtained by flat mounting the endothelial surface and the subsequent digitisation. Comparisons were undertaken between the control unsutured eye and the lid-sutured eye endothelium, and between the central endothelial areas compared to the peripheral endothelial areas in both the myopic and the normal corneas. Calculation of the contribution to the endothelial change by hypertrophy and mitosis were calculated using Bahn's formula. RESULTS: Total endothelial surface area increased significantly over time in the myopic model compared to control eyes but the mean cell area of endothelial cells remained the same for both the enlarged myopic endothelial surface area and in the normal controls. Sampling from the central and the peripheral corneal endothelial surface also disclosed no difference. The mean cell area did increase steadily with age but was the same for both normal and myopic corneas. CONCLUSIONS: It would appear that there are equal contributions from hypertrophy and mitosis in the myopic group and the normal corneal group with a slightly increasing trend towards mitotic activity in the myopic corneal endothelial layer.

The cytomorphology of ocular surface squamous neoplasia by using impression cytology.

BACKGROUND: The term ocular surface squamous neoplasia (OSSN) encompasses conjunctival and corneal intraepithelial neoplasia through to invasive squamous cell carcinoma of the ocular surface. The disease is related to prolonged exposure to solar ultraviolet light and has been proposed as an acquired immune deficiency syndrome-associated tumor. To the authors' knowledge, very few reports describing the cytology of these lesions have been published. METHODS: Impression cytology (IC) samples collected from the eyes of patients with a range of ocular surface diseases were available for study. From these, 267 sets of impressions had subsequent histopathology that had been collected within 6 months of the IC, and which indicated the presence of OSSN. The IC from these cases was used to describe the cytomorphology of intraepithelial and invasive OSSN. RESULTS: Within the intraepithelial group, keratinized dysplastic cells that often were accompanied by hyperkeratosis, syncytial-like groupings, and nonkeratinized dysplastic cells were described. Within the invasive group, cases with significant keratinization and an additional group of cases with little keratinization and sometimes also prominent macronucleoli were described. Keratinized cases were the most numerous in both the intraepithelial and invasive groups. A description also was given of a low number of cases with cytology and also subsequent histopathology indicating the presence of intraepithelial OSSN, in the absence of a clinically detectable lesion. CONCLUSIONS: This detailed description of the cytomorphology of a high number of cases of OSSN with confirmation by histopathology should assist others with little experience of the cytology of these lesions to examine them with increased confidence. Cancer (Cancer Cytopathol)

Use of topical cyclosporin for conjunctival manifestations of actinic prurigo.

PURPOSE: To report the successful treatment of conjunctival manifestations of actinic prurigo with topical cyclosporin. METHODS: A 12-year-old female with extensive limbal lesions and chronic conjunctivitis secondary to actinic prurigo was treated with topical cyclosporin, and a rapid clinical response was observed. RESULTS: The patient had the limbal lesions surgically excised. The lesions completely recurred over the first 2 postoperative months. Treatment with topical steroids and vitamin A ointment was unsuccessful. The patient was then treated with cyclosporine 2% drops and a dramatic improvement occurred. Over a 3-month period, the lesions completely resolved. CONCLUSION: Cyclosporine eyedrops may be an effective treatment for the conjunctival manifestations of actinic prurigo.

Ultraviolet light exposure as a risk factor for ocular melanoma in Queensland, Australia.

The state of Queensland, Australia, has one of the highest incidences of cutaneous melanoma in the world; this has been linked to the high sun exposure of the mainly Caucasian population. The role of sun exposure in the development of ocular melanoma (melanoma of the conjunctiva, iris, ciliary body or choroid) remains unclear. A case-control study involving 125 patients with ocular melanoma treated between 1972 and 1996, and 375 age- and sex-matched controls (three for each patient) was performed. A standardised telephone questionnaire examining ultraviolet exposure and other potential risk factors was administered. Cumulative lifetime ocular ultraviolet B (UV-B) exposure was assessed using the Melbourne Visual Impairment Project instrument. Risk factors identified include personal history of melanoma of the skin (odds ratio [OR] 2. 42, 95% confidence interval [CI] 0.88, 6.62) or other skin cancers (OR 1.52, CI 0.99, 2.35), and family history of ocu-lar melanoma (OR 6.89, CI 0.70, 67.38). Protective factors included olive or black skin (OR 0.72, CI 0.40, 1.31), brown iris colour (OR 0.89, CI 0.51, 1.54), high resistance to sunburn (OR 0.58, CI 0.26, 1.31), and wearing prescription glasses (OR 0.78, CI 0.48, 1.25). Sunglass wearing was not found to be protective. Cumulative lifetime ocular UV-B exposure was not found to be a risk factor for ocular melanoma. However, there were too few cases of conjunctival and iris melanoma for these to be analysed as separate sub-groups.

Knowledge of sunlight effects on the eyes and protective behaviors in adolescents.

The knowledge of the effects of sunlight on the eyes and protective behaviors were studied in an adolescent population. A group of 652 systematically sampled students aged between 13 and 17 years was surveyed with a standardized questionnaire in Brisbane, Australia in October-November, 1995. Survey data on the knowledge of sunlight effects on the eyes, ultraviolet light, eye and body protection as well as risk factors for ultraviolet (UV) exposure were relatively ranked and totalled to give overall scores. Of the 652 subjects, 330 (51%) were female. Most subjects (568 or 88%) were aged between 15 and 16 years. Overall, this group of subjects demonstrated a moderate level of knowledge with respect to UV, sunlight and the eyes. The knowledge of the effects of sunlight and body protection was higher than the knowledge of the effects of sunlight and eye protection. Almost three-quarters (462 or 71%) of the subjects owned a pair of sunglasses. The mean age at which subjects started to wear sunglasses was 10.4 years. However, most subjects (528 or 81%) only wore sunglasses occasionally or not at all. The reported frequency of wearing sunglasses was significantly related to personal, family and peer attitudes to such use, but not to media advertizing. Assessment of adolescent knowledge is important in the formulation of health promotion strategies designed to prevent excessive UV exposure at this young age.

Laser in situ keratomileusis interface deposits.

BACKGROUND: A clinical investigation was undertaken to determine the origin of a brown interface deposit that developed in 15 eyes after laser in situ keratomileusis (LASIK). METHODS: The LASIK procedure was evaluated and agents that were thought to be related to these brown deposits in the interface were eliminated sequentially. Eyes were observed after LASIK for presence or absence of the deposit. RESULTS: Twenty-five consecutive LASIK eyes in which a methylcellulose sponge was eliminated as a protector of the hinge developed no similar interface deposits. CONCLUSION: The use of a dry methylcellulose sponge to protect the hinge may result in unexpected interface deposits after LASIK.

Postoperative suture manipulation for control of corneal graft astigmatism.

PURPOSE: To assess the effect on post-keratoplasty astigmatism of postoperative manipulation of a single running suture. METHODS: All corneal transplant patients in whom a single 10/0 nylon running suture was placed between November 1990 and April 1996 were included in a prospective study of the effect of manipulation of the suture at the earliest possible time after surgery when the keratometry became possible by virtue of the epithelial surface integrity and where this revealed astigmatism of greater than 2 D. RESULTS: One hundred and ninety eyes underwent suture manipulation and were followed up. Follow up on 30 eyes was discontinued. Repeat manipulation of the running suture was the most common reason for discontinuation of follow up. The remaining patients were followed for a mean (+/- SD) 415.5+/-326.4 days. Mean astigmatism of 7.8+/-3.1 D was reduced to 1.7+/-2.0 D immediately after manipulation, but regressed to 3.0+/-1.9 D (n = 76) by 1 year. The suture was removed in 32 patients. Twenty-five eyes had post-removal astigmatism measurements. In these 25 eyes, astigmatic error appeared not to revert to premanipulation levels. The only significant complication was one broken suture at manipulation. CONCLUSIONS: Early suture manipulation is effective in reducing suture in post-keratoplasty astigmatism, but some regression is seen.

Comparative pupil dilation using phenylephrine alone or in combination with tropicamide.

OBJECTIVE: A prevalence survey of actinic and other eye diseases was conducted in Nambour, Queensland, Australia, in 1992. Pupils were dilated with phenylephrine alone for cataract identification because there were concerns that patient discomfort, due to cycloplegia occurring with the usual dilating agents of tropicamide and phenylephrine, may influence future compliance in an associated intervention study. This validation study was undertaken to measure the possible underestimation of cataract prevalence in this community study, which may have occurred because of inadequate dilation from phenylephrine alone. DESIGN: The study design was a repeated measures experimental design. PARTICIPANTS: Forty-seven normal subjects participated in the study. Both eyes were tested. INTERVENTION: Pupil diameter after dilation with three drops of 10% phenylephrine alone was compared with pupil diameter after dilation with three drops of 10% phenylephrine together with three drops of 1% tropicamide. The two regimens were given to the same subjects 1 week apart. Reversal was attempted with thymoxamine hydrochloride 0.5%. MAIN OUTCOME MEASURES: Pupil diameter was assessed using a Neitz cataract camera, and accommodation reserve also was measured. Subjects' subjective appreciation of return of ocular function was assessed by a questionnaire. Repeated measures analysis of variance, paired t test, McNemar's test, and Wilcoxon signed rank test were used to analyze outcomes. RESULTS: Mean maximum pupil size with 10% phenylephrine and 1% tropicamide was significantly larger than pupil size after the use of 10% phenylephrine alone (F1,19 = 18.99, P = 0.0003). However, there was no significant difference between the two dilation regimens when comparing the proportion of subjects who dilated to 6 mm or more (McNemar's X(2)1 = 2.7, P > 0.1). Compared with 10% phenylephrine and 1% tropicamide, pupil diameters were significantly smaller (t46 = 16.77, P = 0.0001), and accommodation reserve greater (t46 = 4.14, P = 0.0001), 40 minutes after reversal with thymoxamine in the group dilated with 10% phenylephrine alone. CONCLUSION: Pupil dilation with 10% phenylephrine alone, if allowed at least 40 minutes to act, will be as satisfactory for the identification of cataracts in a normal population as 10% phenylephrine and 1% tropicamide and is more acceptable because of reduced problems with glare and accommodation.

Corneoscleral transplantation for end stage corneal disease.

AIM: To describe the prognosis and complications of corneoscleral transplantation in the management of end stage eye disease. METHODS: A case series is presented of 23 patients who have undergone corneoscleral transplantation (> or = 11 mm). Patients were examined for visual acuity, intraocular pressure, recurrence of disease process, epithelialisation of the graft, signs of rejection, and other potential complications. RESULTS: 14 patients retained their eye, with six maintaining a clear graft. Vision ranged from 6/30 to no perception of light. 13 patients developed glaucoma (range 25-69 mm Hg), with six patients requiring surgical intervention. 12 patients required tarsorrhaphy to promote epithelialisation. Only two grafts resulted in typical rejection. CONCLUSIONS: The technique of corneoscleral transplantation can salvage otherwise end stage eye disease, but the results are poor with respect to maintenance of vision. These patients need careful follow up because of potential complications of glaucoma, epithelial defects, rejection, and recurrence of disease.

Retrospective study of ocular surface squamous neoplasia.

BACKGROUND: Ocular surface squamous neoplasia (OSSN) encompasses the conditions of simple dysplasia to carcinoma in situ to invasive squamous cell carcinoma. It has a high rate of recurrence after treatment and the potential to metastasize. The present retrospective study was aimed at further defining the characteristics and clinical course of OSSN. METHODS: With ethical approval, the records of all major pathology laboratories in Queensland were surveyed. Two hundred and eighty-eight cases were identified: 155 dysplasia, 71 carcinomas in situ and 62 invasive squamous cell carcinoma. The records were analysed and an attempt was made to contact and re-examine the patients. RESULTS: Ocular surface squamous neoplasia occurs mainly in males (78.5%) with a mean age of 60.1 years (range 20-88 years). They present as irritation (40.1%) and are located usually at the limbus (87.8%). The majority of OSSN are treated by simple excision (87.5%), after which there is a high rate of recurrence (23.3%). The main predictors for recurrence include histological grade of the lesion, corneal location and larger size (> 2 mm). CONCLUSIONS: Management of OSSN requires adequate excision and careful follow up to monitor any recurrence. As with other ultraviolet light-related conditions, preventative measures must remain the key to disease control.

Measurement of ultraviolet radiation at the surface of the eye.

PURPOSE: A new method for the measurement of ultraviolet radiation that reaches the surface of the eye is described. METHODS: The technique uses contact lenses produced from the ultraviolet-sensitive plastic polysulfone. Two types of polysulfone contact lenses (9 mm and 12 mm in diameter) were manufactured from a polysulfone rod. The 9-mm polysulfone contact lens could be calibrated and used to determine the ocular-to-ambient exposure ratio in a fashion similar to polysulfone film badges. The 12-mm polysulfone contact lens was designed as a "piggy-back" lens and required a larger diameter polymethlylmethacrylate carrier lens to fit the eye adequately. A method of in vivo stabilization was developed to minimize lens rotation. RESULTS: During four wearing trials, the ratio of ocular-to-ambient ultraviolet exposure ranged from 4% to 23%. CONCLUSIONS: Contact lenses manufactured from polysulfone offer the potential to study the exposure of the eye to ultraviolet radiation. The smaller diameter lens can measure an average ocular exposure, whereas the larger, stabilized, piggy-back design may allow regional dose assessment across the entire lens surface.

Efficacy of a training programme designed to teach cervical smear screeners to identify ocular surface squamous neoplasia using conjunctival impression cytology.

Ocular surface squamous neoplasia (OSSN) is a recently proposed term introduced to encompass both intraepithelial neoplasia and invasive squamous cell carcinoma of the conjunctiva and cornea. A teaching programme incorporating a manual, slide sets, and an evaluation test was developed. The aim was to teach experienced cervical smear screeners to evaluate ocular surface specimens collected by conjunctival impression cytology, with a minimum of individual tuition. The use of the manual was well accepted and half of the original six candidates were able to master the new skill adequately within 8 h. It was considered that the differences between the cytology of OSSN and the equivalent lesions of the uterine cervix are sufficient to prevent some experienced screeners acquiring these skills rapidly.

Keratoconus: the clinical experience of a Brisbane ophthalmologist.

Keratoconus is a common corneal dystrophy. In order to characterize an Australian experience with this condition, a retrospective study of 295 consecutive cases of keratoconus presenting to one Brisbane ophthalmologist (GR) was performed. The majority (82%) of patients presented before the age of 40 years. Keratoconus was bilateral in 240 (81%) patients and unilateral in 55 (19%) patients. Family history of keratoconus occurred in 43 (15%) patients. A history of atopy and eye rubbing was obtained in 131 (44%) and 30 (10%) patients, respectively. Follow-up after a mean +/- SD of 5 +/- 5 years was obtained in 188 patients. Treatment modalities at follow-up included rigid gas-permeable contact lenses (CL) (48%), PMMA CL (3%), corneal graft (25%), no treatment (13%), spectacles (9%), soft CL (2%). The annual corneal graft rate was 3% per year per eye. With careful contact lens fitting most keratoconus patients will not require a corneal graft.