Aims: To study the long term toxic effects of intraocular benzalkonium chloride (BAC). Methods: 19 patients exposed to intraocular BAC preserved viscoelastic during cataract surgery in February 1999 developed severe striate keratopathy immediately postoperatively. 16 patients, including two who underwent penetrating keratoplasty, were studied in the period April to June 2000. Ocular symptoms, visual acuity, biomicroscopy, intraocular pressure, dilated funduscopy, specular endothelial microscopy, and corneal pachymetry findings were recorded. The corneal and iris specimens of the two patients who underwent keratoplasty were studied by light, transmission, and scanning electron microscopy. Results: Six males and 10 females, aged 64-98 years, were studied 14-16 months postoperatively. All patients were symptomatic. 12 patients had best corrected visual acuity of 6/12 or better and four patients of between 6/18 and 6/60. Five patients had corneal epithelial oedema and 11 had Descemet's membrane folds. The central corneal thickness, 620 (SD 71) µm, in affected eyes was significantly higher (p<0.005, two tailed paired t test) than that of the contralateral eyes, 563 (SD 48) µm. The endothelial cell density was significantly lower (p<0. . There was no significant difference in the coefficient of variation of cell size between the two eyes (p=0.3, two tailed paired t test). Two corneal specimens displayed morphological features of bullous keratopathy and other nonspecific abnormalities. Extracellular melanosomes were present in a portion of the iris of one case. Conclusion: BAC is toxic to the corneal endothelium when used intraocularly, leading to severe striate keratopathy. This cleared in most cases but left varying degrees of residual stromal thickening in all eyes. If penetrating keratoplasty is required the results are excellent.

The SOG scheme demonstrates acceptable levels of accuracy between SOG and glaucoma consultant. This scheme allows many stable low-risk patients to remain out of hospital eye department outpatient clinics.

Purpose This study assessed the role of specialist optometrists who were working in the community and sharing the care for glaucoma patients with, and under close supervision of, a consultant ophthalmologist working in the Hospital Eye Services (HES) to ensure high-quality standards, safety, and care. Methods From February 2005 onwards, the majority of all new glaucoma referrals to our eye department were diverted to our specialist optometrists in glaucoma (SOGs) in their own community practices. Selected patients in the HES setting who were already diagnosed with stable glaucoma were also transferred to the SOGs. The completed clinical finding details of the SOGs, including fundus photographs and Humphrey visual field tests, were scrutinised by the project lead.

LETTERS

Aim This paper describes the experience at a district general hospital of coping with an abrupt onset of calcification of Hydroview intraocular lens (IOL) implants requiring exchange surgery mostly for symptoms of glare, even though the visual acuities were relatively good. Methods In this retrospective study, the operative details of 174 consecutive lens exchanges by one surgeon were retrieved from the surgeon's notes. Of these, pre and postoperative details of 106 consecutive patients were obtained from the hospital notes. Results Of the 174 lens exchanges, all were sutureless except one and 31 eyes (18%) had had previous capsulotomies. Of 143 eyes with intact posterior capsules, eight (5.6%) needed anterior vitrectomy. Lens replacements were in the bag in 136 (95%), in the sulcus in five (3.5%), and in the anterior chamber in two (1.5%). Of the 31 eyes with previous capsulotomies, 10 (32%) needed anterior vitrectomy. Lens replacements were in the bag in 22 (71%) and in the sulcus in the remaining nine cases (29%). Postoperatively the bestcorrected visual acuity was improved in 53%, remained the same in 35%, and deteriorated in 12%. Conclusion The lens exchange procedure was mostly predictable with satisfactory visual results allowing preoperative counselling of risks to be similar to that for cataract surgery. The onset and resolution of the period of implantation of lenses requiring exchange has not been explained.