Asbjørn M. Tønjum

Risk Factors for Intraoperative Complications in 1000 Extracapsular Cataract Cases

A prospective study of the risk factors in extracapsular surgery was carried out between October 1984 and April 1986. One thousand extracapsular cataract extractions were performed by seven physicians. Decreasing pupil size was the only statistically significant risk factor for vitreous loss (P = 0.0002). Zonular breaks occurred more commonly with pseudoexfoliation syndrome (PX) (P less than 0.0001), with decreasing pupil size (P less than 0.0001), and with one surgeon who used the Simcoe aspirating needle (Storz) exclusively (P = 0.0001). It is acknowledged that it is very difficult to standardize what constitutes a small zonular break; hence, the increase in zonular breaks recorded by this surgeon may have been due only to his using less stringent criteria than the others. Capsule breaks had no significant risk factors at the 0.01 level. High myopia, advanced cataract, glaucoma, advanced age, and diabetes mellitus were not found to be risk factors for vitreous loss, zonular breaks, or capsular breaks.

EFFECTS OF BENZALKONIUM CHLORIDE UPON THE CORNEAL EPITHELIUM STUDIED WITH SCANNING ELECTRON MICROSCOPY

The corneal surface of rabbits and vervet monkeys was studied by means of scanning electron microscopy after the influence of the cationic surfactant, benzalkonium chloride. The concentration of the drug was 0.02% or 0.01% and the exposure time was 2 or 4 min. The corneas treated with the drug had characteristic changes with small holes or more extensive lesions of the superficial cell membranes, and loss of microvilli or microplicae. The damage was considered to be due to the lytic effect of benzalkonium chloride upon the plasma membranes.

Permeability of horseradish peroxidase in the rabbit corneal epithelium.

Horseradish peroxidase has been used in the cornea as a histochemical tracer for both light and electron microscopy. When the rabbit corneae, as little damaged as possible, were mounted between two lucite chambers containing a nutrient solution, and exposed to this enzyme on the epithelial side, no peroxidase reaction products were detected below the epithelial surface. When the endothelial side had been exposed for one hour or more, the enzyme had moved across the endothelium, the Descemets membrane, the stroma, and up between the epithelial cells to the zonulae occludentes between the cells of the most superficial layer, adjacent to the tear film.

Exfoliation syndrome among Saudis.

Abstract. The prevalence of exfoliation syndrome among Saudis was determined during the National Survey of Blindness and Eye Disease in 1984 in Kingdom of Saudi Arabia. The subsample of this study consists of 376 persons aged 40 years or more from 50 different locations examined under mydriasis by the authors using Kowa hand‐held microscope. There were 192 men and 184 women with the mean age of 56.0 ± 1.2 years (median 53.5 years, range 40–95 years).

GONIOSCOPY IN TRAUMATIC HYPHEMA

Traumatic hyphema is a condition frequently seen in ophthalmological practice, and severe post-traumatic lesions may be present in the anterior chamber angle. Until recently little attention has been paid to these lesions. However, Wolf/ &. Zimmermnn (1962) gave an account of the pathological anatomical picture of the lesions. They also associated the chamber angle lesions with the development of chronic secondary glaucoma of the injured eyes. It therefore seems to be of interest to present some gonioscopic observations which show the frequency and extent of the lesions in the chamber angle caused by blunt traumata. The relationship between these lesions and the regional vessels and the pupillary changes is also noted.

INTRAOCULAR PRESSURE AND FACILITY OF OUTFLOW LATE AFTER OCULAR CONTUSION

Chamber angle deformities usually exist after ocular contusion, the most common lesion being a tear of the anterior face of the ciliary body (Blanton, 1964, Howard, Hutchinson & Frederick, 1965, Tonjum, 1966). Also, disturbances of intraocular hydrodynamics may develop early after the trauma andlor as a late phenomenon. Increase andJor decrease of intraocular pressure may be present. Glaucoma may sometimes be found late after a contusion. In eyes with extensive goniosynechiae that develop after a contusion, a glaucoma may be explained by the visible morphological changes, which indicate a causal relationship between the contusion and bhe secondary glaucoma. In some eyes with glaucoma late after contusion, visible damage of the trabecular meshwork area cannot be demonstrated. These glaucomas may be primary simple ones, developing at random in eyes with previous contusion. However, the contusion angle deformities may, in one way or another, influence the intraocular hydrodynamics, indicating a causal relationship between the contusions and the glaucomas. In the present study the intraocular pressure and the facility of outflow have been determined in a specially selected sample of patients with previous ocular contusion. Tears of the anterior face of the ciliary body were the main visible pathological changes with possible causal relationship to the alterations of intraocular hydrodynamics.

IN VITRO STUDIES ON PEROXIDASE MOVEMENT IN THE EPITHELIUM OF PROSTAGLANDIN‐TREATED RABBIT CILIARY BODIES

The movement of horseradish peroxidase (HRP) in the epithelium of isolated rabbit iris/ciliary body preparations, has been studied with the electron microscope. HRP was applied at the stromal side of the epithelium, and was left for 60 and 120 min. The distribution pattern of HRP found in the epithelium of the iridial and ciliary processes is consistent with in vivo studies, i.e. the progression of HRP is blocked at the site of the zonula occludens of the superficial epithelium. The HRP distribution pattern found in the iris epithelium indicates that also the superficial epithelial cells of this epithelium are girdled by zonulae occludentes.

MOVEMENT OF HORSERADISH PEROXIDASE IN THE CORNEA, SCLERA AND THE ANTERIOR UVEA

The anterior chambers of rabbit, monkey and human eyes were perfused with horseradish peroxidase. The perfusion was started immediately after enucleation of the monkey and human eyes, while the rabbit eyes were perfused in situ after the animals had been killed. Comparative results were obtained after 1 h of perfusion and were mainly based on frozen sections. Intensive staining was found in the Descemets membrane, the sclera and the iridial stroma, considerably more than in the corneal stroma and in the ciliary body base. In the vervet monkey and human eyes only traces of peroxidase reaction products were seen in the stroma of the ciliary body base. The movement of the protein tracer from the anterior chamber into the corneal stroma is probably dependent upon vesicular transport across the corneal endothelium. The Descemets membrane was interpreted to be more porous than the corneal stroma. A trans‐corneal and a corneo‐scleral movement appeared to be more efficient than the uveo‐scleral one, at least in the vervet monkey and the human eyes.

PROTEIN DIFFUSION BARRIERS IN THE ANTERIOR UVEA OF THE RABBIT EYE

The distribution in the anterior uvea of the protein tracer horseradish peroxidase, has been studied in eyes of albino rabbits. The tracer was injected intravenously 30 or 60 min before enucleation. Light microscopy of frozen sections and of semithin sections of Epon‐embedded material revealed: 1. The stroma of the iridial and ciliary processes, and the choroid contained considerable amounts of peroxidase reaction product. 2. In the iris and the ciliary body apart from the processes (the ciliary body base), the peroxidase reaction product was confined to the vessels. 3. A sharp demarcation of peroxidase activity was observed between the iridial processes and the iris stroma, and between the ciliary processes and the ciliary body base.

LENS DISLOCATION FOLLOWING OCULAR CONTUSION

Dislocation of the lens is a feared complication in ocular contusion. Posterior luxation or subluxation is by fa r the most frequent form, and it is this which is of interest in this paper. Gregersen (1962) noted 4.5 O/O of lens dislocation in 200 successive eyes with traumatic hyphema. T o n j u m (1966) found an incidence of 9.40//0 in 53 successive eyes. The selection of these samples seems to be comparable. Secondary glaucoma is frequent after lens dislocation, both earIy after the trauma and in a delayed, chronic form. Hegner (1915) found 51.40/0, Maggiore (1924) 100/0, and Kutschera & Ebner (1964) 43.7 O/O of eyes with secondary glaucoma in series with traumatic lens subluxation. When the lens was completely luxated into the vitreous body, the incidence of secondary glaucoma was found by Maggiore (1924), 10 O/O, Ringelhan & Elschnig (1931), 9.6 O/O, Kutschere & Ebner (1964), 61 010. The pathogenesis of the glaucoma after ocular contusion with lens dislocation has been widely discussed. When the chamber angle is closed, the cause of the development of the glaucoma is easily understood, and these cases are not of interest in the present study. When the angle is open, the glaucoma is more difficult to explain. The theory that the dislocated lens irritates the ciliary body, resulting in an increased production of aqueous humor, has many supporters. Contrary to this, Rodman (1963) claimed that the secondary glaucoma was caused by the recession of the chamber angle and a coincidental damage of the trabecular meshwork with decreased facility of outflow. I t would be of interest to investigate eyes with traumatic lens dislocation with open chamber angles, in order to determine the deformities of the chamber angle caused by the contusion, and to correlate the possible hydrodynamic changes with the grade of the chamber angle deformities, whether or not glaucoma was present. Therefore the present sample of patients with ocular