Say Aun Quah

Pharmacokinetics of vancomycin following intracameral bolus injection in patients undergoing phacoemulsification cataract surgery

Aim: To determine the elimination kinetics of intracameral vancomycin administered as a bolus injection at the end of phacoemulsification cataract surgery. Methods: Vancomycin 1 mg/0.1 ml saline solution was administered to 19 patients by intracameral bolus injection at the end of routine cataract surgery. The aqueous concentration of vancomycin was determined in nine patients 1 minute after administration and in 10 patients 18–24 hours postoperatively. Aqueous samples were obtained by inserting a Rycroft cannula into the anterior chamber via the side port incision. Fluorescence polarisation immunoassay was used to calculate the aqueous vancomycin concentration. Results: The median (interquartile range) vancomycin concentration was 5458 (4756–6389) mg/l at 1 minute and 40.6 (25.9–47.1) mg/l 18 to 24 hours (median 19 hours) postoperatively. The vancomycin concentration exceeded the minimum inhibitory concentration (MIC) of endophthalmitis-causing gram-positive bacteria by a factor of 4 for up to 26 hours postoperatively. No adverse event or reaction was noted. Conclusion: Following bolus intracameral injection at the end of cataract surgery the concentration of vancomycin in the anterior chamber vastly exceeds its MIC for at least 24 hours but is predicted to fall below the MIC after 33 hours.

Treatment of refractory vernal ulcers with large-diameter bandage contact lenses.

Purpose. To report two cases of refractory vernal ulcers in which the fitting of a large-diameter (22 mm) hydrogel (Contaflex T75) bandage contact lens (BCL) ameliorated the signs and symptoms of the condition. Methods. Two patients with refractory vernal ulcers are described. Mechanisms of the effect of a large-diameter lens across the ocular surface are discussed in this condition. Results. The first patient is a 10-year-old boy who had been treated unsuccessfully for a left vernal corneal ulcer with topical prednisolone 0.5% and olopatadine. The vernal ulcer resolved 2 weeks after the fitting of a large-diameter BCL. The second patient is a 4-year-old boy who had been intolerant of all his previous topical medications partly because of his ocular discomfort in association with the right vernal ulcer. A large-diameter BCL was fitted in his right eye. The BCL was removed 2 weeks later with complete healing of the corneal vernal ulcer. Owing to his improved comfort, the patient was able to tolerate topical prednisolone 0.5% drops. Conclusions. Large-diameter BCLs may be a useful treatment option in the management of refractory vernal ulcers.

The use of voriconazole in the treatment of Aspergillus fumigatus keratitis

There are a few reports of the use of voriconazole for the treatment of fungal keratitis.1–5 We report another case of its apparent success in Aspergillus fumigatus keratitis and discuss the dilemma of prescribing an expensive drug in the absence of defined ophthalmic therapeutic levels. A 51 year old diabetic man presented a week after being poked in his eye by a child’s finger, with a 3.0×3.5 mm central corneal ulcer overlying full thickness stromal infiltrate with associated hypopyon (fig 1). Pinhole visual acuity was 2/60 in this eye. Topical ciprofloxacin 0.3% was started. Aspergillus fumigatus was isolated after 48 hours’ incubation and topical amphotericin B 0.15%, voriconazole 1% hourly, and …

Sequential versus combined penetrating keratoplasty and cataract surgery.

Purpose. To compare the refractive and visual outcomes of combined penetrating keratoplasty and cataract surgery (triple procedure) with those of sequential surgery (penetrating keratoplasty followed by secondary cataract extraction and posterior chamber intraocular lens implantation). Methods. Forty-six consecutive patients undergoing triple procedure or sequential surgery performed by two surgeons were reviewed retrospectively. The triple procedure group consisted of 23 patients and the sequential surgery group also consisted of 23 patients. Refractive and visual outcomes were collected and analyzed with at least 1 year of follow-up for both groups. Both the difference from target and the variability of the refractive outcome were analyzed. Results. Best spectacle corrected visual acuity of 6/12 or better was achieved in 16 eyes (69.8%) in the triple procedure group and in 19 eyes (82.6%) in the sequential surgery group. For both the triple and sequential groups, there was no difference between the mean postoperative refractive outcome (−2.73/+1.05 × 109 SD = 4.30/1.42/4.43) and (−1.33/+0.79 × 175 SD = 2.39/1.16/2.33) compared with the mean target refraction (−0.77, SD = 1.16 and −0.43, SD = 0.99), (p = 0.39 and 0.48), respectively. In addition, there was no significant difference in the variability of the refractive outcome between the two groups (p > 0.99). Conclusions. Sequential surgery appears to offer no significant advantages over the triple procedure in terms of refractive predictability or variability. There was a slight trend toward more patients achieving 6/12 or better vision in the sequential group.

Conjunctival-corneal melt in association with carotid artery stenosis.

Purpose To report a case of severe conjunctival-corneal melt in association with carotid artery stenosis. Methods Observational case report. Results A 76-year-old man with a history of bilateral severe carotid artery occlusion and nonarteritic ischemic optic neuropathy developed a spontaneous bulbar conjunctival defect. Despite intensive lubrication, and attempts at surgical closure including an amniotic membrane patch graft, it progressed with subsequent adjacent corneal perforation. Thorough investigations revealed no underlying disease, except markedly delayed episcleral vessel filling on anterior segment fluorescein angiography. Conclusions Neovascularisation is a known factor in the inhibition of ulceration. In light of the findings in this report, ocular ischemia should be considered as a cause or contributing factor in the differential diagnosis of conjunctival-corneal melt.

Keratoconus associated with CSNB1.

A 35-year-old man with best corrected visual acuities of −18.00/+10.00×180 (6/60) OD and −10.00/+8.00×5 (6/36) OS. Bilateral steep central corneal thinning, paracentral ectasia and Vogts striae were present; normal fundi. Corneal topography disclosed 7.4 dioptres of irregular astigmatism in the central 3 mm with thinning (335 &mgr;m). Electroretinography (ERG) showed no response. There were no medical or environmental influences for his keratoconus. Occurrence of keratoconus and CSNB in the patient may represent a chance association, but keratoconus has not been previously linked with CSNB1 either as a chance or true association though both show genetic predisposition.

Keratoconus associated with congenital stationary night blindness type 1.

A 35-year-old man presented with keratoconus; his best corrected visual acuities were −18.00/+10.00 ×180 (6/60) oculus dexter and −10.00/+8.00 ×5 (6/36) oculus sinister. Bilateral steep central corneal thinning, paracentral ectasia and Vogts striae were present. Normal fundi. Corneal topography disclosed 7.4 dioptres of irregular astigmatism in the central 3 mm with thinning (335 &mgr;m). Electroretinography (ERG) showed no response. There were no medical or environmental influences for his keratoconus. Occurrence of keratoconus and congenital stationary night blindness (CSNB) in the patient may represent a chance association, but keratoconus has not been previously linked with CSNB1 either as a chance or true association though both show genetic predisposition.

In-vivo scanning of Ascher intrastromal corneal ring opacity

An 80-year-old man was seen with abnormal corneal appearances. He was asymptomatic with no previous ocular, medical or drug history. Visual acuities were 6/6 in both eyes unaided; with ocular examination revealing bilateral 0.1 mm wide white intrastromal corneal ring opacities 7.8 mm and 7.7 mm in diameter in the right and left eyes, respectively (fig 1). Corneal sensation was normal with no evidence of thinning, scarring or vascularisation. The remaining ocular examination was normal. Blood tests for lipid, protein and autoimmune markers were normal. Corneal pachymetry …

Keratoconus associated with CSNB1

A 35-year-old man was referred with progressive impairment of vision. He was previously diagnosed with anisometropic amblyobia and registered partially sighted. He had lifelong problems of night vision and described a family pedigree suggestive of X-linked inheritance, with two generations of male members affected with nyctalopia and high myopia. No male-to-male transmission occurred and female relatives were unaffected. Family members could not be contacted. Refraction showed distorted retinsocopy reflexes, with best corrected visual acuities of −18.00/+10.00 ×180 (6/60) OD and −10.00/+8.00 ×5 (6/36) OS. …