Topical Cysteamine Research Articles

The Effect of Topical Cysteamine Drops on Reducing Crystal Formation Within the Cornea of Patients Affected by Nephropathic Cystinosis

We studied the usefulness of topical cysteamine ophthalmic drops in reducing crystal formation within the corneas of patients affected by nephropathic cystinosis. A dosage of 0.3% cysteamine given four times daily was chosen as a more manageable method than a previously reported protocol of hourly administration of 0.11% drops. No reduction in crystal formation was observed in our patients; they were followed for seven months.

A Randomized Placebo-Controlled Trial of Cysteamine Eye Drops in Nephropathic Cystinosis

Eighteen patients with nephropathic cystinosis who were younger than 42 months and 11 patients 4 to 31 years of age were entered into a double-masked, randomized, placebo-controlled trial of topical cysteamine eye drops between November 1985 and September 1989. Eight of the younger patients and 2 of the older patients showed marked clearing of corneal crystals in one eye compared with the fellow eye. When the code was broken, all 10 patients were found to have received cysteamine eye drops in the improved eye. Of the remaining 19 patients 4 were unavailable for follow-up. In 15 patients no marked difference was noted between the two eyes. Eight have presumably been in the protocol for too short a time and several have been poor compliers with the therapy. These results not only demonstrate the potential for primary prevention of corneal crystal deposition but also, for the first time, offer the possibility of reversing the corneal complications of cystinosis in older patients.

Range of toxicity of topical cysteamine in rabbit eyes.

Cysteamine eye drops in concentrations from 0.1% to 10% were tested in albino rabbits in both short and long-term experiments. Toxicity, consisting of an inflammatory response, was proportional to the cysteamine concentration and absent at concentrations at or below 0.5%.

Ocular changes in some progressive hereditary nephropathies

Ocular involvement is a common feature of three hereditary nephropathies: cystinosis, nephronophthisis and Alport's syndrome. The follow-up of 25 cases of infantile cystinosis over a period of 26 years demonstrated that the corneal and retinal epithelium were affected in the same way as the kidney epithelium. Corneal involvement induced photophobia and discomfort, but actual blindness was mainly due to retinal involvement, and therefore no corneal graft was performed. The use of topical cysteamine appears to be promising, but its production raises many questions so no definitive conclusions may be made. Since 1965, 51 patients with nephronophthisis have had ocular examinations; all patients had characteristic clinical symptoms and histological findings. The first group, which consisted of 18 children, all under 10 years of age, was found to have obvious chorioretinal degeneration. The second group, which consisted of 11 children, had a normal ocular examination and normal electroretinogram (ERG). The third group, consisting of 22 children, had a normal clinical examination but ERG tracings with variable alterations. In 28 instances of Alport's syndrome, two types of ocular abnormalities have been observed. In six cases, an anterior lenticonus was noted, which caused a major decline in visual acuity. Retinopathy, which did not affect vision, was observed in 13 cases.