A preliminary trial to determine whether prevention of dark adaptation affects the course of early diabetic retinopathy.

UNLABELLED: This study was designed to determine whether a new form of treatment of diabetic retinopathy (DR) was acceptable to patients and whether reduction in the maximal activity of rods in diabetes could affect the progress of DR. METHODS: In 12 patients, trans-lid retinal illumination of one eye was employed during sleep to prevent the depolarisation of rods and thus reduce their metabolic activity. TECHNIQUES: A headband was used to place a source of chemical light over one eye, with its fellow as a control. MEASUREMENTS: Colour contrast thresholds were measured before and after a period of treatment in treated eyes, and the changes were compared to those in untreated fellow eyes, and areas of 'dark retinal anomalies' (microaneurysms, dot haemorrhages) were measured at the same time points. RESULTS: Patients found this intervention to be acceptable, and no adverse effects were noted. In the majority of cases, and for each outcome measure, the treated eyes improved relative to their fellows. The intervention significantly reduced the tritan thresholds in treated eyes relative to their fellows (P=0.03), and the area of dark retinal anomalies decreased in treated eyes and increased in untreated eyes, with a similar probability. CONCLUSIONS: The study showed that this intervention is safe. Although the study was not powered to study efficacy, the results are promising and consistent with other reports that indicate the retina in DR is suffering from hypoxia; however, further trials should be undertaken.

Tear film and meibomian gland functions in psoriasis.

Tear secretion, tear film stability, and meibomian gland function (plugging, volume, and thickness) were assessed in patients with psoriasis vulgaris (n = 70). As compared to that of the healthy controls (n = 125) mean Schirmer I value of psoriatic patients was found to be in normal ranges, whereas tear film break-up time was significantly lowered. When evaluating meibomian gland function, psoriatic patients were found to have higher plugging and thickness indices but a normal volume of meibomian gland secretion. These findings suggested an obstructive type of meibomian gland dysfunction in psoriatic patients which might result from increased turnover of the epithelia lining the meibomian gland duct.

Cavernous hemangioma with cone dysfunction.

We report a 13-year-old male who complained of strabismus and low visual acuity in the right eye. Saccular aneurysms filled with dark-colored blood were noted in the upper nasal quadrant of the right fundus. Ishihara color plates and Lanthony's new color test revealed a red-green color defect. Cone response and 30-Hz flicker responses were nearly absent. Cavernous hemangioma of the retina is a rare vascular hamartoma; the associated findings show cone dysfunction concomitant with this peripheral lesion.

Meibomian gland dysfunction and tear film abnormalities in rosacea.

In order to determine the relationship between meibomian gland dysfunction and tear film abnormalities in rosacea, tear film flow and stability and meibomian gland function were assessed in 43 consecutive patients. Schirmer, tear film break-up time, and meibomian gland function values in patients with ocular rosacea (n = 28) were found to be significantly decreased as compared with those of the patients with only cutaneous involvement and control patients (p > 0.05). In patients with dermatologic rosacea (n = 15) these values were not different from those of the age- and sex-matched controls (p > 0.05). The effects of tetracycline and meibomian gland expression therapy also were investigated in patients with ocular rosacea. Neither meibomian gland expression therapy nor tetracycline administration had beneficial effects on decreased tear secretion, but tetracycline improved the break-up time values. Our findings showed a positive relationship between tear film abnormalities and meibomian gland dysfunction in patients with rosacea. Decreased tear secretion in patients with ocular rosacea would seem to be a result of structural changes secondary to meibomian gland dysfunction, and short break-up time might be due to an abnormal meibum composition.

Pattern-reversal electroretinograms and visual evoked potentials in branch retinal vein occlusion.

We recorded pattern electroretinograms and visual evoked potentials in a group of selected patients with unilateral uncomplicated branch retinal vein occlusion. To document the effects of preexisting risk factors, patients were divided into three groups: diabetes mellitus, hypertension with hyperlipidemia and no systemic disease. The transient and steady-state pattern electroretinogram and visual evoked potential amplitudes were significantly reduced and visual evoked potential peak times were delayed relative to the fellow eyes and age-matched normal subjects. There was a second amplitude reduction relative to the other patient groups in both the affected and fellow eyes of the diabetes mellitus group, which was indicative of an additive effect of diabetes mellitus.

An unusual fundus finding in a patient with optic nerve pit syndrome.

In a study of 12 patients with optic nerve pits, a female patient presented an unusual fundus finding in which there were many flat grey-white lesions in both eyes. These lesions covered a large area of the fundus and extended from the posterior pole to the periphery. There was an optic pit in the right eye and an inferior coloboma in the left eye. The visual acuities and the clinical findings remained unchanged over the follow-up period of 2 years. Fluorescein angiographic and electrophysiological examinations suggested that these lesions were probably located at or beneath the retinal pigment epithelium.