Entrapment of ophthalmic ointment in the cornea

No eye pad for corneal abrasion

We have carried out a randomised clinical trial to assess the healing rate and level of discomfort experienced in two groups of patients with simple traumatic corneal abrasions. Patients treated with antibiotic ointment and mydriatic alone have a significantly improved healing rate compared with those treated with antibiotic ointment, mydriatic and a double eye pad with bandage (0.05 > p > 0.02). There was no significant difference in the level of discomfort experienced by the two groups.

Adverse external ocular effects of topical ophthalmic medications

Medical and pharmacologic research of recent years has led to the development of many potent and efficacious topical ophthalmic medications. Unfortunately, many of these drugs are potentially toxic or allergenic, and their adverse effects have themselves become important external ocular diseases. This paper presents a classification of these adverse effects and provides a review of their etiology, pathogenesis, histopathology, diagnosis, and management. It is hoped that this information will be helpful to ophthalmologists in their efforts to anticipate, prevent, recognize, and treat drug-induced ocular problems and that it will serve to emphasize the importance of avoiding the ill-considered use of medications.

Ophthalmic ointments

The use of ointments as an ocular drug vehicle adds an important dimension to topical therapy. Ointments are well tolerated, fairly safe, and provide an excellent means for enhanced ocular contact time. In the case of certain antibiotics, this improved contact time yields increased ocular drug levels. However, experimental data indicate that corticosteroid ointments do not penetrate into the eye as well as do suspension preparations. This may relate to the binding of the drug to the ointment base and also to the particular steroid compound. Like other ophthalmic preparations, ointments may become contaminated. Ophthalmic ointments should not be instilled into eyes with open wounds. Instillation of ointments into postoperative eyes where wound closure is secure appears to be safe and effective.

Recurrent erosion of the cornea

Altogether, 80 patients aged between 24 and 73 years with recurrent erosion of the cornea have been studied and compared with a control group of 200. The patients' erosions were divisible into macroform and microform types. The macroform occurred in 10%, the microform in 56%, and both types in the same patients in 31%. The macroform was more commonly related to trauma than the microform. However, many (40%) were spontaneous in origin. The most common cause of the initial trauma was a finger nail. The recurrences occurred at around the time of waking, either just before or just after. Difficulty in opening the eye occurred in 10%. There was little evidence of precipitating factors, but eye rubbing was admitted by 10% and barbiturates were implicated in 3%. The corneae were examined in the healed state, when a high incidence (59%) were found to have superficial corneal dystrophies of the fingerprint lines, bleb, and Bietti's lacunar (map-like) types. These are considered individually, particular attention being paid to the distinction between the various types of line resembling the fingerprint line. Epithelial microcysts were also a common finding (59%) and were sometimes of the Cogan type. In only 11% of patients were there no corneal signs in the healed state. The need for careful examination of the cornea by retroillumination, using both the iris and the fundus, is stressed. The control group, in contrast, showed a very low incidence of dystrophies and cysts. Treatment was given initially with either drops or ointment and no differences in healing were found. Debridement was performed in 12 eyes as an initial treatment and also in four eyes which were not healing on medical treatment. Debridement assisted healing, but did not prevent recurrence. One eye was treated with debridement and scarification and seven with carbolization. These procedures appeared to reduce the recurrence rate. Sodium chloride ointment 5% was found useful as a prophylactic taken at bedtime, and the recurrence rate increased when it was withdrawn.

Corneal superficial unwettable defect. II. Electron microscopic study

Corneal biopsy specimens of 6 patients with this particular affection were studies with the electron microscope. In addition to the routine electron microscopic methods, staining with ruthenium red was performed on one excised specimen. Marked changes were found in the region of Bowman's membrane, which was altered either superficially or in its total width. Its collagen fibrils became rough and intensively electron-dense, forming a granular or structureless trabecular meshwork. Intertrabecular spaces were filled with special electron-lucent material, which also formed a continuous layer on the surface of the altered Bowman's membrane. Filamentous structures resembling fingerprints were observed in certain areas of these spaces; and after staining with ruthenium red, numerob granules were also visible. Both these structures are considered by the author to be acid mucopolysaccharides. There is further discussed on the correlation of these findings with previous histochemical findings; the author gives special attention to the question whether waxy substances-eye ointment bases-could have been deposited in the pathologically altered Bowman's membrane.