S. Pohjola

Ocular manifestations of idiopathic hypoparathyroidism.

Hypoparathyroidism encountered as a sequela of thyroid surgery is a wellknown complication. But the idiopathic form described by Beumer and Falkenheim (54) is probably not commonly known since the time lapse between the onset of the symptoms of the disease and arrival a t a diagnosis averages 10 years (8). Over a hundred cases have been reported, and in three-fourths of them the disease began a t under 20 years of age (58). Idiopathic hypoparathyroidism (IPH) is characterised by low serum calcium and elevated inorganic phosphorus of the serum. In addition, phosphorus diuresis is increased after the administration of parathormone (EllsworthHowards test). The clinical symptoms are caused chiefly by hypocalcemia. They are chronic tetany, especially attacks of the grand ma1 type, ocular symptoms, intracerebral calcifications, trophic disorders of the ectoderm and moniliasis. Pseudohypoparathyroidism (PSH) resembles IPH but differs from it in the following respects: the condition is hereditary, the metacarpal and metatarsal bones are short, there are subcutaneous calcifications, the face is round, the trunk short and broad and the kidneys do not respond to parathormone (e. g. 4,8). Although the ocular symptoms of I P H are common and often dominate the disease picture, with the exception of cataract they have been discussed relatively little in ophthalmological literature (48, 44. 64). On the other hand, general surveys by internal specialists and pediatricians have taken the ocular symptoms into consideration (40, 8, 58). The present author reports a case of his own and analyses the ocular symptoms of 1 1 7 published cases.

NAUSEA AND VOMITING AFTER OCULAR SURGERY

The frequency of postoperative nausea and vomiting following common ocular operations was studied in 110 male and 125 female patients anaesthetized by four different techniques: N2O‐ O2‐relaxant anaesthesia, neurolept analgesia, N2O‐O2‐halothane anaesthesia, and local anaesthesia with 2% mepivacaine. There were no significant differences between these various techniques in regard to the frequency of nausea and vomiting, although local anaesthesia seemed to give the best results in this respect.

MYOPIA AND SCLERAL RIGIDITY

In a previous investigation (Castrdn and Pohjola 1961) we came to the same conclusion as many other ophthalmologists that the scleral rigidity of the myopic eye is lower than that in an emmetropic or a hypermetropic eye. I t seemed wellgrounded to us to study the relation between scleral rigidity and the degree of myopia, because the opinions about it are somewhat incongruous for the present. Furthermore, in an other previous work (Castrkn and Pohjola 1961) we noticed a tendency to a decrease of scleral rigidity at puberty, which might be associated with the origination of myopia. In 1937 Friedenwald found, that axial myopia of some diopters did not influence noticeable the scleral rigidity. With increasing myopia, however, the rigidity decreased. Friedenwald noticed further that in extreme myopia (more than 20 diopters) the rigidity did not decrease any more on the contrary it rised. He supposed this was due to the sclera having been stretched out to the uttermost. The scleral rigidity became again a question of current interest when Goldmann invented his applanation tonometer. He also found a low rigidity coefficient in myopic eyes. In 1959 Bock and Stepanik arrived at the same conclusion when determining the scleral rigidity coefficient of 57 myopic eyes. In myopia of 6-12 diopters the average of the coefficient was 0.017 and in eyes of 13-16 diopters 0.014. When the degree of myopia was 17-20 diopters the average coefficient was 0.015 and in myopic eyes of 21-25 diopters as high as 0.018. On the other hand, according to Becker and Gay (1959) the rigidity coefficient was lower than normal in myopic eyes of 1-5 diopters, but in myopic eyes of more than 5 diopters the rigidity gradually reached the normal level. In their study the average rigidity coefficient was 0.022, the mean in myopic eyes 0.018 and in eyes with 1-5 diopters myopia 0.015.

Refraction and scleral rigidity.

The scleral rigidity is low in myopic eyes (Friedenwald 1937 and Goldmann 1955). According to Goldmann & Schmidt (1957), the rigidity coefficient of niyopic eyes varied between 0.0060 and 0.0136. They reported a mean coefficient value of 0.0203, whereas Friedenwalds tables are based on the rigidity coefficient of 0.0215. Lavergne ,pC Weekers & Prijot (1957) found in their investigation, that the rigidity coefficient of myopic eyes was 0.0150-0.0214. Heinzen & Luder & Miiller (1958) reported an average value of 0.0233 in hyperopic eyes, in emmetropic eyes 0.0220. In myopic eyes the coefficient varied between 0.0192 and 0.021 I. The results of Draeger (1959) are to a great extent similar: in hyperopic eyes 0.021 1-0.0220, in emmetropic 0.0199, and in myopic eyes 0.0144-0.0165. In a previous publication we reported a low rigidity coefficient at puberty, a period when myopia often develops or increases (Castrtn 8. Pohjola 1961). The present paper sets out first to study the rigidity coefficient by different refraction groups and second, to reveal if the rigidity coefficient in myopic eyes at puberty would be particularly low.

UNILATERAL EXOPHTHALMOS with special reference to endocrine exophthalmos and pseudotumor

Unilateral exophthalmos is caused either by a small orbital volume or space-taking process in the orbit. Also an increased intracranial tension (Knudtzon 1952) and elevated local venous pressure can give rise to it. From 82 consecutive cases of O’Brien and Leinfelder (1935) the most frequent cause of unilateral exophthalmos was orbital abscess. In this series there were only two cases of endocrine exophthalmos. In Godtfredsen’s material (1947) there was no case of endocrine exophthalmos among 107 patients with orbital disease. Three-fourths of the patients had an orbital tumor. Drescher and Renedict (1950) reviewed 177 patients with unilateral exophthalmos. They found endocrine exophthalmos the most common cause with 23 percent of cases. SchultL & al. (1961) reported on 59 patients with asymmetric proptosis. The most common cause was endocrine exophthalmos (36%). Neurosurgeons have a different impression of the incidence of expanding lesions of the orbit when they review the findings in orbital explorations. The commonest cause in one series was meningeoma with 31 percent, carotid aneurysms and fistulas were second with 12 percent. Endocrine exophthalmos comprised only two percent of patients (Van Buren aqd Poppen 1957). Radiologists, on the other hand, reported mucocele as the most common cause followed by inflammation, carcinoma of the sinus, and meningeoma (Bullock et al. 1959). Thus the etiology of unilateral exophthalmos seems to vary considerably, particularly as regards the incidence of endocrine exophthalmos. The present study was undertaken to reveal the causes of unilateral exophthalrnos in Finland with a special reference to endocrine exoph

SGLERAL RIGIDITY AT PUBERTY

It is a well-known fact today that the intraocuIar pressure values obtained by the Schi~tz tonometer may differ notably from the true values, by more than 12.5 mm H g even. This is due more frequently to abnormal rigidity of the sclera than e. g. to the curvature of the cornea (Schmidt 1961). The use of a special rigidity coefficient by means of which the real intraocular pressure could be established was proposed by Friedenwald (1 937). Only since the appearance of Goldmann’s applanation tonometer, however, has it been possible to determine intraocular pressure and consequently scleral rigidity with considerably greater reliability than earlier. It was found that the deviation of a single rigidity estimate with the method of paired Schic?tz readings was twice as great as that obtained with applanation and Schietz tonometer (CastrCn and Pohjola 1961). Scleral rigidity and intraocular pressure are different at different ages according to Draeger (1959), with the rigidity coefficient decreasing and intraocular pressure increasing with age. His series, however, included only 14 eyes from persons under 20 and the rigidity value obtained from them was not statistically reliable. His total material consisted of 175 eyes. Rigidity seemed to decrease with age also in Ytteborg’s (1960) material of 166 eyes (the age of the persons examined was 12-92 years). The differences, however, were not significant. He, too, observed an increase in intraocular pressure with age though the difference was no more than 0.1 mm Hg between subjects aged 12-19 and 25-45. Twenty five of the eyes belonged to persons aged 12-19. On the other hand, Goodside (1959) for instance reported that the rigidity coefficient increases with age. His material was large, 852 eyes, but the measurements were made by the so-called paired weights method and not with an applanation tonometer.

CLINICAL EVALUATION OF THE DRAEGER APPLANATION TONOMETER

The Goldmann applanation tonometer has one important advantage over the Schistz tonometer: the result of measurement is independent of the coefficient of scleral rigidity. A disadvantage, however, is that the intraocular pressure cannot without special arrangements be measured in the supine position, as would be desirable for instance in recording the morning pressure for the diurnal curve and in examining children with congenital glaucoma in general anesthesia. To eliminate this disadvantage, Draeger 1-4 modified the Goldmann tonometer so as to make pressure measurement independent of the patient’s position. According to Draeger’s 3,4 reports, the new tonometer gives results which do not differ significantly from those obtained with the Goldmann tonometer. Before routine clinical application of the Draeger instrument, we have wished to examine the pressure values obtainable in our hands with this new tonometer by comparing them with the corresponding data for the Goldmann tonometer.

The measurement of scleral rigidity. Evaluation of various methods used.

As early as 1863, Donders was aware of the significance of the elastic properties of the ocular wall in the measurement of intraocular tension. In 1937, Friedenwald devised the method of paired tonometric readings for estimating the coefficient of the scleral rigidity. Since then, and particularly during the last few years, a number of publications have appeared which have dealt with the clinical estimation of the rigidity coefficient, but not infrequently the results obtained have been controversial, which leads one to conclude that there is considerable scope for error in the estimation of the coefficient. The clinical value of a reliable and practical method for the estimation of the rigidity coefficient is obvious. In the diagnosis of early glaucomas, in particular, when the Schintz tonometer is used, a knowledge of the ,,rigidity<< has proved indispensable, particularly in myopic eyes. As described by Friedenwald, the rigidity coefficient can be determined by means of his Nomogram and the Sch i~ tz tonometer with two different plunger loads. The 1954 made Nomogram soon proved inaccurate and was revised in 1955. Different Schintz tonometers, even carefully standardized, do not give consistent readings even in the same eye. Wi th tonometry the chance of error in method is also considerable according to Rohrschneider and Kiichle (1954), k 1 Schiatz scale unit for a single measurement. The effect of massage unfortunately invalidates rapidly repeated tonometric readings attempted to reduce this error in tonometry (Leydhecker & Leydhecker 1956, Schmidt 1955 and Kronfeld 1959). Other factors which influence the rigidity coefficient include the corneal curvature (Schmidt 1960) and the volume of the eye. Phillips and Quick (1960), experimenting with hollow rubber spheres, suggested by analogy that

EFFECT OF GUANETHIDINE ON GLAUCOMATOUS EYES

Guanethidine or 2(octahydro-l’-azocinyl)aethyl-guanidin-sulphate is a sympaticolyticum synthetized by Ciba. At first the drug was used for lowering of the blood pressure (Maxwell, Plummer, Schneider,Povalski & DanieI 1960). Because of the sympathicolytic properties of the drug experiments have been made to solve its value as an antiglaucomatous agent. Keates, Krishna & Leopold (1960) established a clear decrease of the intraocular pressure when injecting guanethidine intravenously. Also when applied locally as eye drops the same effect on the intraocular pressure could be obtained (e. g. Kutschera, Kuchle and Stepanik 1961). According to the last-mentioned investigations, guanethidine in 10 per cent solution instilled in the conjunctival sac causes a lowering of the intraocular pressure at last in one hour. The maximal effect will be obtained after 6-8 hours. Further, only a moderate miosis follows but no change of the accommodation. Instead of that the palpebral aperture will narrow and according to Stepanik also the pressure of the fellow eye in which no drops were instilled decreased. The pressure of this control eye increased to the initial value in half an hour, and the blood pressure, too, decreased for the same t inie. (On the contrary, in the rabbit experiments of Oosterhuis (1961) the pupil (Mated and the intraocular pressure increased after the instillation of guanet hidine. To the next day the pressure decreased and the mydriasis disappeared. All experiments mentioned above have been performed using 10 per cent guanethidine solution. Oosterhuis developed same results in his animal experiments also when using 4 per cent but not with 2 per cent solution of the drug. ’) Received 2nd April 1962.

THE INTRAOCULAR PRESSURE LEVEL AND SCLERAL RIGIDITY IN NORMOTENSIVE HUMAN EYES

According to Friedenwald (1937), the scleral rigidity coefficient is independent from the variations of the intraocular pressure. Also Moses and Tarkkanen (1959) came to the same result when using the differential applanation tonometry. Draeger (1959) could not find any definite correlation between the pressure and ocular rigidity when investigating 72 eyes. Prijot and Weekers (1959), too, could not show any changes in the rigidity as a function of the hypertension produced by injection of intraocular fluid. Also Kronfeld (1959) writes that both the combined applanation and impression tonometry, and the differential impression tonometry, and also the differential applanation tonometry, all >>these clinical methods, as practiced so far, have not shown any trend toward a decrease of ocular rigidity with rising pressure<<. However, the reports concerning this question are by no means going along the same lines. Ma&, Wanko and Grimes (1958) established in their post mortem measurements of nine human eyes that by increasing intraocular pressure the rigidity usually increases up to a critical point and then begins to decrease, while in some eyes only a decrease can be observed. Perkins and Gloster (1957 and 1959) found in experiments with rabbit eyes, that by rising intraocular pressure also the rigidity increased, but the state of things was just the opposite in their experiments with enucleated human eyes. According to Kruse (1960), the scleral rigidity diminished with increasing intraocular pressure in his study of 100 human normotensive eyes by using differential applanation tonometry. Also Goodside (1959), using the two-weight method on 500 patients, and Drapger and Miiller (1960), using the applanation tonometry and weight tonometry and the water provocation test came to the same result. McBain (1958) and Miiller (1960) observed also a decrease of the rigidity