Eye drop instillation technique in patients with glaucoma.

AIMS: To evaluate the technique of eye drop instillation in patients with glaucoma and assess factors associated with a good technique. METHODS: A cross-sectional observational study of 85 participants using self-administered topical medication for glaucoma or ocular hypertension. Patients were asked to demonstrate how they normally instil eye drops using a 5-ml bottle of sterile artificial tear solution. The procedure was recorded and assessed by two masked graders. Whether the patient had been previously shown how to instil drops, the number of eye medications used, and self-perceived difficulty of using drops were also recorded. Univariable logistic regression was performed to relate each variable to drop technique and variables with P<0.2 were included in a multivariable logistic regression analysis. RESULTS: 54.1% (46/85) of patients had a poor drop technique, 11.8% (10/85) missed the eye, 15.3% (13/85) touched the tip of the bottle to the bulbar conjunctiva or cornea, and 27.1% (23/85) touched the eyelid or lashes with the bottle tip. 81.2% (69/85) could not recall being shown how to instil eye drops. In the multivariable model, previous instruction regarding drop instillation technique was significantly associated with good technique (adjusted OR=8.17, 95% CI 2.02-33.05, P=0.003) and increasing age was associated with poor technique (adjusted OR=0.95, 95% CI 0.91-0.99, P=0.017). CONCLUSIONS: Education relating to eye drop instillation technique is significantly associated with a patient's ability to instil drops correctly. The assessment of a patient's ability to instil eye drops correctly should be a routine part of the glaucoma examination.

A histological analysis of lens capsules stained with trypan blue for capsulorrhexis in phacoemulsification cataract surgery.

PURPOSE: Staining of anterior lens capsules with dye to facilitate completion of continuous curvilinear capsulorrhexis is now being used more frequently in phacoemulsification of white and mature cataracts with poor red reflexes. This study examined the histological characteristics of anterior lens capsules stained with trypan blue. The layer(s) of the lens capsule that stained with dye and the extent of accumulation of dye in these layers of the lens capsule were determined. To the best of our knowledge this has not been described before. METHODS: A series of 10 stained lens capsules were analysed histologically. The dye used in this study consisted of a standard sterile, noninflammatory, nonpyrogenic, 2 ml solution containing 0.6 mg/ml of trypan blue. Following capsulorrhexis, samples were sent to the laboratory for histological analysis. Frozen sections (8 microm) were prepared and examined with the light microscope. All 10 capsules were cut by frozen section to preserve trypan blue staining (which would be leached by processing) and then subjected to immunohistochemistry for collagen IV. Immunohistochemical analysis using markers for type IV collagen were done on formalin-fixed specimens for morphological comparison with the frozen sections. A counterstain highlighted the epithelium. RESULTS: Continuous curvilinear capsulorrhexis was successfully and easily completed in all cases without any complications. Frozen section analysis using light microscopy demonstrated accumulation of trypan blue dye in the basement membrane of the lens capsule. Staining was concentrated in the portion of the membrane adjacent to the lens epithelium. The lens epithelium could not be clearly identified on the frozen sections. Consequently, immunohistochemical analysis with markers for type IV collagen was performed. A counterstain highlighted the epithelium. This confirmed that the layer staining with trypan blue was the basement membrane, a consistent feature on all the specimens. CONCLUSION: Trypan blue selectively stains the basement membrane of the anterior lens capsule. There is a concentration of dye in the basement membrane adjacent to the lens epithelial cell layer. The lens cortex does not appear clinically to stain with trypan blue. This enables surgeons to distinguish the lens capsule from the cortex and provides sufficient contrast for successful completion of continuous curvilinear capsulorrhexis during cataract surgery.