The use of dye in ophthalmology.

Dyes are used in current ophthalmological practice, both as diagnostic and therapeutic aids. Commonly used dyes include sodium fluorescein, indocyanine green, rose bengal and methylene blue. The properties of these agents are outlined, along with indications for their use. The article concentrates mainly on intravenous sodium fluorescein and fundus fluorescein angiography, although topical and intracameral use of other dyes is highlighted. Ocular tissue responses are discussed, in particular those of the retinal vasculature and choroidal circulation. The normal blood-retinal barriers and pathology of abnormal angiography findings is presented. Pharmacokinetics and pharmacodynamics of intravenous dye are discussed, along with potential systemic complications.

Topographic and keratometric astigmatism up to 1 year following small flap trabeculectomy (microtrabeculectomy).

AIM: To determine the induced corneal astigmatism by measuring the changes in manual keratometry and computerised corneal videokeratoscopy up to 1 year following small flap trabeculectomy (microtrabeculectomy). METHOD: A prospective study of a case series of small flap trabeculectomy procedures performed at the 90 degree meridian on 16 eyes of 16 patients, all followed to 1 year postoperatively. Changes in manual keratometry and computerised videokeratoscopy (Eyesys) readings were analysed by vector analysis and vector decomposition techniques. RESULTS: By vector analysis, the mean surgically induced refractive change (SIRC) cylinder power vectors induced at 1, 3, 6, and 12 months as measured by manual keratometry were 0.68, 0.38, 0.52, and 0.55 dioptres, and by keratography 0.75, 0.66, 0.59, and 0.64 dioptres. Vector decomposition on the induced vector cylinders on manual keratometry resulted in a "with the rule" mean vector of 0.52 and 0.22 dioptres at 1 and 3 months and an "against the rule" mean vector of 0.16 and 0.16 dioptres at the same time points (p=0.03 and 0.28 respectively). Vector decomposition at 6 and 12 months revealed no significant with the rule changes induced. Similar analysis on the videokeratoscopy results revealed significant induced with the rule astigmatism until 3 months, but not at 6 and 12 months postoperatively. CONCLUSION: Small flap trabeculectomy (microtrabeculectomy) produces smaller changes in corneal curvature that resolve sooner than previous reports of larger flap techniques.

Long-term follow-up of a single continuous adjustable suture in penetrating keratoplasty.

Penetrating keratoplasty was performed on 30 patients using a single adjustable continuous 10/0 nylon suture. Seventeen patients had astigmatism of 4.00 dioptre cylinders (DC) or more and were adjusted. The latest adjustment was at 32 weeks. Following adjustment there was a significant reduction in median post-keratoplasty astigmatism from 6.00 DC to 2.50 DC (p < 0.001). Thirteen patients, with astigmatism of 4.00 DC or less, were not adjusted. Median astigmatism for the non-adjusted group was 3.00 DC and for the entire group was 2.88 DC. Long-term refraction and suture status were monitored with time. Mean follow-up was 112 weeks (range 53-170 weeks). Over the study period the entire group showed significant 'long-term astigmatic drift' (LTAD), from 2.88 DC to 3.25 DC (median drift, 1.25 DC; range, 0.00-5.50 DC) (p < 0.001). Suture adjustment and suture removal showed no significant effect on LTAD. With suture removal between 32 and 84 weeks median LTAD was 1.50 DC. For suture removal after 84 weeks, median LTAD was also 1.50 DC, but the range of LTAD was 1.50 DC, compared with a larger range of 5.00 DC in the earlier suture removal group. The technique of single continuous adjustable sutures for penetrating keratoplasty is safe, effective in reducing astigmatism, but may need modification to further enhance long-term refractive stability.

Non-attendance at ophthalmology outpatient clinics.

Non-attendance at outpatient clinics is a common problem, resulting in inefficiency and wasted resources. To establish the reasons why patients failed to attend their outpatient clinic appointment and to assess what proportion of these failed attendances were potentially preventable, we conducted a 13-month prospective postal survey of clinic non-attenders to our hospital. Of 5248 appointments made during the study, 521 were not kept (9.9%). Of these, 224 patients replied to the questionnaire, a response rate of 43%, with new patients more likely to not attend than old patients (odds ratio 2.7, P < 0.001). From the replies, 27.3% of non-attendances could be described as 'clerical error' with a further 17.9% due to patients failing to remember their appointment. Based on the replies received, a better organized outpatient booking system and a simple postal reminder could potentially prevent at least 40% of non-attendances.

Dye enhanced laser photocoagulation in the treatment of a peripapillary subretinal neovascular membrane.

A 45-year-old female with an elevated peripapillary subretinal neovascular membrane was treated with dye enhanced laser photocoagulation, using indocyanine green and the diode laser. Following treatment the membrane regressed, with flattening of the lesion. No side effects occurred and excellent visual acuity was maintained over a 12 month follow-up period.

Recurrent corneal erosion: clinical features.

The clinical features of a group of 30 patients with recalcitrant recurrent corneal erosions (i.e. those who failed to respond to conventional therapy) were evaluated. Associated ocular and facial abnormalities were documented. Meibomian gland dysfunction was present in all patients as manifest by dropout and inspissation of the meibomian glands, reduced tear film break-up time and debris in the tear film. Dropout of meibomian glands was present in 25 (83%) patients and was maximum in the medial half of the lid in 21 (84%) of these 25 patients. Tear film break-up time was reduced in all patients, being instant in 7 (23%), between 1 and 5 seconds in 22 (74%) and between 10 and 15 seconds in 1 (3%) patient. Superficial corneal abnormalities were present in 28 (93%) patients as manifest by maps, dots and fingerprints. Facial abnormalities such as telangiectasia, rhinophyma and acne rosacea were present in 22 (73%) patients. The findings of our study suggest an association between recalcitrant recurrent corneal erosions and meibomian gland dysfunction.

Oral tetracycline in the treatment of recurrent corneal erosions.

We report the results of a prospective, randomised controlled, 24 week trial to assess the efficacy of oral tetracycline and oral tetracycline with topical prednisolone in the treatment of recalcitrant recurrent corneal erosions, i.e. those which fail to respond to standard therapy. A total of 30 patients were randomly allocated to either standard treatment (group A), standard treatment and oral tetracycline (group B) or standard treatment, oral tetracycline and topical prednisolone (group C). Treatment groups B and C were instructed to perform daily lid hygiene. There was a significant reduction in the number of recurrent corneal erosions during the 24 week study period in group B (p = 0.04) and in group C (p = 0.0003) but not in group A (p = 0.66). There was a significant difference in the accelerated healing time of recurrent corneal microerosions between groups A and B (p = 0.001) and between groups A and C (p = 0.001). There was a significant improvement in the symptom scores during the study in treatment groups B and C (p = 0.005) but not in group A (p = 0.15). We conclude that lid hygiene and oral oxytetracycline 250 mg twice daily for 12 weeks with or without topical prednisolone for the first 7 days is beneficial in the management of recalcitrant recurrent corneal erosions.

The treatment of epiphora with balloon dacryocystoplasty.

We examine a new treatment for epiphora: balloon dilatation of the nasolacrimal duct, or dacryocystoplasty. The procedure, which was performed as an out-patient procedure under local anaesthetic, was carried out on 20 patients with epiphora, 17 due to anatomical and 3 due to functional obstruction. There was an overall success rate of 60%, with complete relief of symptoms in 4 patients and a symptomatic improvement in another 8 (follow-up 2-9 months, mean 4.2 months). All patients tolerated the procedure well with minimal per-operative and post-operative discomfort. A higher success rate was seen in those patients with either a low anatomical or a functional obstruction. The procedure can be easily repeated and, if unsuccessful, still allows a dacryocystorhinostomy to be performed at a later date.