The value of a phenol red impregnated thread for differentiating between the aqueous and non-aqueous deficient dry eye

To determine the clinical viability of a phenol red impregnated cotton thread in differentiating between normal, aqueous deficient and non-aqueous deficient dry eyes. Subjects were recruited on the basis of subjective symptoms, tear stability, rose bengal staining, Schirmer test, conjunctival hyperaemia, patency and number of meibomian glands, presence of mucin strands, appearance of lower tear meniscus. Based on the outcome of the tests, subjects were categorised as either aqueous deficient dry eyes, non-aqueous dry eyes or normals. Subjects were randomised and a thread was applied by inserting into the lower fornix of the right eye and leaving the thread in place for 120 sec. All data was collected under similar ambient conditions. After gathering all the data, the codes were broken. Mean (+/- S.D.) thread wetting values were, all dry eyes (n = 59) 18.4 mm (5.9). Aqueous deficient dry eyes (n = 35), 15.5 mm (4.6). Non-aqueous deficient dry eyes [n = 24], 22.7 mm (5.0). For the normals (n = 38), 19.4 mm (5.0). Differences between (i) normals and aqueous deficient dry eyes and (ii) aqueous deficient and non-aqueous deficient dry eyes were significant (p = 0.01). Difference between all dry eyes and normals was not significant. For the aqueous deficient and non-aqueous deficient dry eyes only, using a cut-off value of 20 mm the calculated sensitivity and specificity values were 86% and 83% respectively. This cotton thread test can effectively differentiate between aqueous deficient and non-aqueous deficient dry eye.

Hydroxychloroquine and visual screening in a rheumatology outpatient clinic

OBJECTIVE

To review 10 years' data relating to visual screening of patients taking hydroxychloroquine.

METHODS

Following baseline visual assessment, ophthalmic monitoring was carried out at six monthly intervals on 758 patients while on hydroxychloroquine. This consisted of corrected visual acuity, central field screening with a red Amsler grid, slit lamp examination, and retinoscopy.

RESULTS

None of the patients suffered visual impairment from retinal toxicity, though 12 reported visual disturbance. This was related to ocular muscle imbalance in four. In the remainder, none of the ocular findings was directly attributable to hydroxychloroquine. Ten patients reported defects when tested with a red Amsler grid. None was related to retinal toxicity. Seven patients developed corneal drug deposits which cleared on stopping or reducing the dose of hydroxy-chloroquine.

CONCLUSIONS

The findings support the view that following baseline ophthalmic examination for patients receiving hydroxychloroquine, regular ophthalmic screening is not required if the daily dose is less than 6.5 mg kg-1 and the cumulative dose is less than 200 g.

A classification for dry eyes following comparison of tear thinning time with Schirmer tear test

In a double-blind study a non-invasive method of examining the stability of the precorneal tear film was used to record tear thinning time on a population of 34 independently diagnosed dry eye patients. The results were compared with those for tear output, as inferred from the standard Schirmer tear test, and a correlation coefficient of 0.20 determined. The mean tear thinning time and Schirmer results for the population sample were 6.87 +/- 2.97 sec, and 5.62 +/- 5.69 mm wetting in 5 min, respectively. From a plot of tear thinning time against Schirmer a simple classification for dry eyes can be made. A Type A with normal tear stability and low output accounting for 14.70% of the dry eyes. A Type B with low tear stability and normal output, also accounting for 14.70% of the dry eyes. A Type C with low stability (less than 9.84 sec), and low output (less than 11.31 mm wetting in 5 min) accounting for 70.60% of the dry eyes.