Pituitary Apoplexy in an Ectopic Pituitary Tumour

A case report of a patient with unilateral visual loss, due to infarction in an ectopic pituitary tumour, is presented. Good return of vision followed surgical removal of the tumour.

Polyacrylic Acid Gel in Patients with Dry Eyes: A Randomised Comparison with Polyvinyl Alcohol

Purpose

To compare the safety and efficacy of polyacrylic acid 0.2% (PAA) gel and polyvinylalcohol 1.4% (PVA) in the treatment of patients with dry eyes.

Methods

Eighty-nine patients with dry eyes were randomly allocated to treatment with either PAA (48) or PVA (41) in a prospective, investigator-masked study in two centres. The parameters assessed were daily frequency of instillation of the study medications, ocular signs and symptoms, tear film break up time, Schirmer's test values, local tolerance and global assessment of the improvement following treatment.

Results

The two groups were similar in patient demographics and study parameters at baseline. The total score of symptoms (gritty or foreign body sensation, burning sensation, dry eye sensation, photophobia, others) and signs (conjunctival hyperaemia, ciliary injection, corneal and conjunctival epithelial staining) was reduced significantly more by treatment with PAA than with PVA at both three and six weeks (p<0.0001). The daily frequency of instillation of PAA was significantly less than that PVA on 38 of the 41 (93%) study days. Both PAA and PVA were safe and equally well-tolerated except for blurred vision, usually mild and transient, on PAA. On global assessment of the improvement in their dry eye condition, significantly more PAA patients felt better on treatment at six (p=0.02) weeks compared with those on PVA.

Conclusions

Polyacrylic acid gel was as safe as and more effective than polyvinylalcohol in the treatment of patients with dry eyes.

Nebulised ipratropium causing a unilateral fixed dilated pupil in the critically ill patient: a report of two cases

We describe two cases of a unilateral fixed dilated pupil secondary to the ocular instillation of nebulised ipratropium bromide. In one patient there was no other neurological abnormality. The second patient was unconscious following a cardiac arrest. While a fixed dilated pupil is an alarming sign, if it is caused by ocular instillation of ipratropium bromide the condition will resolve, although it may take up to 24 hours. The differential diagnosis of a unilateral dilated pupil includes partial third nerve palsy, tonic pupil, direct trauma to the eye and pharmacological mydriasis. The diagnosis can often be determined using pilocarpine eye drops.

Pseudoexfoliation and sensorineural hearing loss

AIMS

There is increasing evidence that pseudoexfoliation (PXF) not only affects ocular anterior segment structures, but may also be a systemic disease. This study was undertaken to assess the relationship between PXF and sensorineural hearing loss.

METHODS

Patients with PXF were identified from hospital records and underwent complete ocular examination. The sum of pure-tone hearing thresholds measured at 1, 2 and 3 kHz (HTL1,2,3) in each ear was compared with the ISO 7029 standard sex-matched, median age-associated hearing loss summed over the same frequencies (AAHL1,2,3). The proportion of ears with thresholds higher than the ISO 7029 median AAHL1,2,3 on the same side as eyes without PXF was compared with the proportion of ears ipsilateral to eyes with PXF but without glaucoma and similarly the proportion of ears on the same side as eyes with PXF and glaucoma.

RESULTS

In total, 69 patients were studied, of whom 39 were male (56.5%). The mean age of the male patients was 75.8 years, while that of the female group was 75.1 years. All patients had PXF affecting at least one eye. Overall 101 ears (73.7%) had a higher HTL1,2,3 than the ISO 7029 median AAHL1,2,3 which included 56 ears of 78 in the male group (71.8%) and 45 ears of 59 in the female group (76.3%). There was no significant difference between the proportion of ears with HTL1,2,3 higher than the ISO 7029 median AAHL1,2,3 on the same side as eyes without PXF, with PXF but not glaucoma and with PXF and glaucoma, in either the male or female groups.

CONCLUSIONS

A large proportion of patients with PXF have sensorineural hearing loss in comparison to age-matched controls, regardless of whether or not there is associated glaucoma. This finding supports the theory that PXF may be a systemic condition.

Pupillary autonomic denervation with increasing duration of diabetes mellitus

BACKGROUND/AIMS

The autonomic pupillary changes in type I and II diabetic patients without clinical evidence of diabetic autonomic neuropathy (DAN) were compared with age matched controls. The relation between pupillary and cardiovascular autonomic function was assessed in the diabetic patients.

METHODS

A case-control study was performed with diabetics grouped according to type and duration of diabetes. Static infrared pupillography was used to compare mean dark adapted pupil size and mean percentage changes in pupil size with pilocarpine 0.1% and cocaine 4% in the diabetic and control groups. All diabetic patients underwent cardiovascular autonomic function assessment using the Valsalva ratio, the 30:15 ratio, and testing for orthostatic hypotension.

RESULTS

In total, 72 type I and 69 type II diabetic patients were compared with 120 controls. Mean dark adapted pupil size was significantly smaller in diabetic groups than controls. Except for type I diabetics with disease for less than 5 years, all patient groups had significantly greater mean percentage constriction in pupil size in response to dilute pilocarpine than controls. There was no significant difference between the mean percentage dilatation in response to cocaine 4% in diabetics and controls. A high proportion of patients had normal cardiovascular autonomic function particularly when this was assessed with the Valsalva ratio.

CONCLUSIONS

Denervation hypersensitivity to dilute pilocarpine is a result of damage to the pupillary parasympathetic supply of diabetic patients. This occurs before the pupillary sympathetic pathway is affected, it can be detected early in the disease, and it may be a possible explanation for the small pupil size seen in diabetic patients. Pupillary autonomic dysfunction occurs before cardiovascular autonomic changes and detection of pupil denervation hypersensitivity to dilute pilocarpine is an inexpensive way to detect early DAN.

The pattern of perforating eye injuries in Ireland

BACKGROUND

Almost all perforating eye injuries present to dedicated eye units. Data from eye units are therefore reliable indicators of the incidence of perforating injuries.

AIMS

To establish the aetiology and visual outcome of perforating eye injuries presenting to one unit over a twelve-month period.

METHODS

Patients with eye injury were identified from the operating room register. Case-notes were reviewed and eye examinations were performed to determine current level of vision.

RESULTS

A total of 37 perforating eye injuries were operated on in the 12-month period from January to December 1995. Thirty one patients (83.8%) were male. The mean age was 33.9 years. The chief causes were work related or do-it-yourself (DIY) in 32.4%, miscellaneous accidents in 27.0%, assault in 16.2%, road traffic accidents in 10.8%. Twenty eyes (54.1%) were blind with acuity < 6/60 at their most recent review.

CONCLUSION

Work-related and DIY injuries are the most common causes of eye perforation. Many of these injuries are easily preventable with appropriate eye protection. The proportion of injuries resulting from road traffic accidents was low. Injuries due to assault are becoming more prevalent and carry a poor visual prognosis.

Ocular complications of acoustic neuroma surgery

AIM

To analyse the risk factors involved in the development of ocular complications after acoustic neuroma resection, in particular corneal complications and visual loss, and to identify measures that may reduce these.

METHODS

62 patients who underwent surgery for acoustic neuroma had a standardised ophthalmic examination and retrospective case note review.

RESULTS

At final review (mean 37.6 months), although 38 patients reported ocular symptoms, only 22% saw 6/12 or worse. Patients with hypoaesthetic corneas had a higher incidence of corneal pathology (79%) than those with normal sensation (39%). Lagophthalmos increased the incidence of corneal pathology (to 80%); in those with normal closure, the incidence was only 46%. 20 patients required at least one ophthalmic surgical procedure.

CONCLUSIONS

After acoustic neuroma resection patients place a considerable burden on the ophthalmologist. Immediate referral postoperatively, and frequent review of those with abnormal sensation may reduce the severity of long term ocular complications.

A case of ocular neuromyotonia with tonic pupil

A 48-year old woman with hypertension experienced painful oculomotor nerve palsy. After surgery for a giant aneurysm of the internal carotid artery in the cavernous sinus, phasic constrictions of the pupil developed. Two years later, this phenomenon disappeared and was replaced by intermittent involuntary cyclic spasms elevating the ptosed lid. These cyclic lid movements were not elicited with any eye movement or by increased accommodation. The pupil now manifested the pharmacologic features of a tonic pupil. The explanation for this unique case of ocular neuromyotonia is based on a misdirection phenomenon, possibly caused by ephaptic transmission.

Intra-ocular pressure changes following laryngeal mask airway insertion: a comparative study

We compared the effects of the Brain laryngeal mask airway with a tracheal tube on intra-ocular pressure. Propofol was used as induction agent and atracurium as relaxant. Twenty-six patients with normal intra-ocular pressure undergoing cataract surgery were randomly allocated to two groups. Group A (n = 13) had a laryngeal mask airway inserted and Group B (n = 13) had a tracheal tube inserted. Intra-ocular pressure was measured just before insertion of the airway, 20 s after insertion and at 2 min. In the laryngeal mask airway group there were no significant changes in mean intra-ocular pressure. In the tracheal tube group there was a significant rise in mean intra-ocular pressure at 20 s (p = 0.0056) which returned to pre-insertion levels at 2 min. We conclude that the laryngeal mask airway continues to have advantages over the tracheal tube for ophthalmic surgery despite the use of propofol and atracurium as anaesthetic agents.

Absent meibomian glands: a marker for EEC syndrome

A patient with a 20 year history of severe keratoconjunctivitis of unknown origin was found, on assessment at a blepharitis clinic, to have complete absence of meibomian glands. Further examination revealed the features of EEC syndrome. To our knowledge, this is the only case to have been diagnosed in this way. The ocular complications of EEC syndrome and other ectodermal dysplasias are reviewed.

Association of HLA type with pseudoexfoliation of the lens capsule

AIMS/BACKGROUND

To identify an HLA association with pseudoexfoliation of the lens capsule to support the hypothesis that there is a genetic predisposition to pseudoexfoliation. A randomised trial would be ideal for establishing a relation but is more costly and time consuming to conduct. Case-control studies provide an alternative method of establishing a relation.

METHODS

The study group comprised 128 subjects who presented to a major eye centre with pseudoexfoliation. Data from blood donors representative of the population of Ireland were used to form a control group.

RESULTS

An HLA association with pseudoexfoliation is identified for 14 antigens. Eleven antigens (HLA A1, A33, B8, B47, B51, B53, B57, B62, DR3, DR12, and DR13) are significantly more common in the pseudoexfoliation group while three antigens (HLA B12, B17, and DR2) are significantly less common. Four HLA antigens are strongly associated, with odds ratios of over 7.5.

CONCLUSION

The strength of this HLA association is supportive evidence for a genetic component to the development of pseudoexfoliation of the lens capsule.

Anatomy of the extraneural blood supply to the intracranial oculomotor nerve

AIMS

An anatomical study was undertaken to determine the extraneural blood supply to the intracranial oculomotor nerve.

METHODS

Human tissue blocks containing brainstem, cranial nerves II-VI, body of sphenoid, and associated cavernous sinuses were obtained, injected with contrast material, and dissected using a stereoscopic microscope.

RESULTS

Eleven oculomotor nerves were dissected, the intracranial part being divided into proximal, middle, and distal (intracavernous) parts. The proximal part of the intracranial oculomotor nerve received extraneural nutrient arterioles from thalamoperforating arteries in all specimens and in six nerves this blood supply was supplemented by branches from other brainstem vessels. Four nerves were seen to be penetrated by branches of brainstem vessels and these penetrating arteries also supplied nutrient arterioles. The middle part of the intracranial oculomotor nerve did not receive nutrient arterioles from adjacent arteries. The distal part of the intracranial oculomotor nerve received nutrient arterioles from the inferior cavernous sinus artery in all 11 nerves and in seven nerves this was supplemented by a tentorial artery arising from the meningohypophyseal trunk. The inferior hypophyseal artery arose from the meningohypophyseal trunk in all 11 cavernous sinuses dissected.

CONCLUSION

This study shows a constant pattern to the blood supply of the intracranial oculomotor nerve. It also highlights the close relation between the blood supplies to the intracavernous oculomotor nerve and the pituitary gland.

Early changes in the choroidal vasculature of rats occurring with experimentally induced hypertension

We investigated the early changes in the choroidal vasculature in rats following surgically induced renovascular hypertension. Renovascular hypertension was induced in a group of 12 male Wistar rats using a modified Goldblatt procedure. The rats were divided into four groups, each being sacrificed at weekly intervals, the first group being sacrificed 1 week following the procedure. Vascular casts were prepared of the choroidal circulation using acyl resin (mercox). These were then studied using the scanning electron microscope. No abnormality of the choroidal circulation was noted for the first 2 weeks. At 3 weeks, when a rise in the average mean arterial pressure was noted, nodular lesions were seen in the choroidal arteries and choriocapillaris. These lesions were present in far greater numbers by 4 weeks. It seems likely that the nodular lesions described are microaneurysms and may contribute to the pathogenesis of the clinically described Elschnig spot.

Clinical comparison of three techniques for evaluating visual function behind cataract

The aim of the study was to compare the ability of displacement threshold hyperacuity to identify reduced retinal/neural function in cataract patients with that of the potential acuity meter (PAM) and laser interferometer. Fifty-two patients (mean age 72.0 +/- 10.8 years) admitted for extracapsular cataract extraction were randomly selected for inclusion in the study. Patients underwent routine refraction and logMAR acuity measurement on the eve of cataract surgery. Following pupillary dilation and in random order, the oscillatory displacement threshold (ODT; defined as the smallest detectable displacement of an object) was determined, and predictions of the post-operative acuity were obtained using the PAM and Rodenstock Retinometer (RR). Patients were re-examined approximately 7 weeks post-operatively when logMAR acuities and ODTs were remeasured. On the basis of the results of an independent fundus examination, patients were assigned to either a normal or a pathology group. Increasing cataract density adversely affected the predictions provided by the PAM (p = 0.0001) and ODT (p = 0.0001) techniques, but not the RR (p = 0.137). One-factor ANOVA revealed that pre-operative ODT (p = 0.0001), PAM (p = 0.0001) and RR (p = 0.0004) measures successfully distinguished patients with retinal/neural pathology from normals. Pre-operative cut-off levels to distinguish normal from pathology cases were retrospectively determined for each technique. The cut-off values for the PAM and ODT techniques yielded higher sensitivity and specificity values than was the case for the RR. The results suggest that the predictive abilities of the PAM and ODT techniques are similar, and superior to that of the RR. Further work involving larger numbers of patients with posterior segment pathology is necessary to reveal which technique provides the best means of assessing retinal/neural function in the presence of ocular media opacities.

Adherence of bacteria to intraocular lenses: a prospective study

AIMS

The study was designed to investigate the bacterial flora of the operating field during routine cataract surgery and the source of intraocular lens contamination during the surgery.

METHODS

The normal flora of the external eye and fornices of 17 patients undergoing selective cataract surgery was determined preoperatively. Swabs taken from the eyelid surface and lashes showed coagulase negative staphylococci (CNS) in 90%, Propionibacterium acnes in 62%, Corynebacterium sp in 18%, and Peptostreptococcus in 3% of the patients. The lower fornices of 70% had CNS, 47% P acnes, 6% Staphylococcus aureus, 6% Corynebacterium sp, and 6% Candida.

RESULTS

A sterile PMMA intraocular lens was touched on the upper bulbar conjunctiva immediately before the surgery. Eighty two per cent of lenses grew CNS, 18% P acnes, 18% Bacillus sp, 12% S aureus, and 6% Corynebacterium sp. A second sterile PMMA intraocular lens was left on the drape and near the eye during surgery. Forty seven per cent of these cultured CNS, 12% Corynebacterium sp, and 6% Bacillus sp. A high count of bacteria in the operating field, especially CNS and P acnes can contribute to postoperative inflammation and endophthalmitis.

CONCLUSION

Special measures are needed before and during the surgery to reduce the chance of intraocular inoculation of these bacteria. Use of proper culture media and techniques are necessary to identify these organisms, especially anaerobes, in postoperative inflammation.

Convergence substitution for paralysed horizontal gaze

Three patients with paralysed horizontal gaze are presented. Involuntary use of convergence to assist horizontal gaze was noted as a late feature. All patients showed (1) unilateral or bilateral horizontal gaze palsy (two patients had one and a half syndrome, the other had bilateral nuclear sixth nerve palsies), (2) adduction of both eyes on attempted gaze into the paralysed field, (3) miosis which coincided with adduction. Convergence substitution should be considered in the differential diagnosis of gaze induced strabismus.

Assessing retinal/neural function in patients with cataract using oscillatory displacement thresholds

Oscillatory displacement threshold (ODT) measurement has been proposed as a useful means of assessing retinal/neural function behind cataract. In order to examine the qualitative predictive ability of this technique, the influence of age, simulated cataract, and various posterior segment disorders upon ODT's were investigated. In a separate investigation, thresholds were measured in 30 cataract patients on the eve of surgery, and again 6 to 8 weeks postoperatively. ODT's were found to increase with age (p < 0.001) and were highly resistant to the effects of image degradation as produced by simulated cataract. In addition, thresholds were sensitive to the presence of retinal/neural disorders (p << 0.001). Although not completely independent of the presence of cataract, higher ODT's were measured in cataract patients with coexistent retinal/neural dysfunction than was the case for patients with normal posterior segments (p < 0.001). Preoperative ODT measurement may offer a means of distinguishing between the optical and retinal/neural components of visual impairment in patients with cataract.

Dark adaptation in disabled readers screened for Scotopic Sensitivity Syndrome

A peripheral retina, photoreceptor, or transient visual-system deficit has been suggested as a basis for dyslexia. We performed dark adaptation using a Goldmann-Weekers adaptometer on 41 dyslexic readers subjected to the Irlen Differential Perceptual Schedule for the Scotopic Sensitivity Syndrome and on 23 volunteers of normal reading ability, all aged between 10 and 20 years. 12 of the 41 disabled readers examined had abnormally poor dark adaptation at peripheral retinal locations consistent with a rod processing-system deficit.

The Demodex mite population in rosacea

BACKGROUND

The cause of rosacea is unknown; among other factors a causative role has been postulated for the hair follicle mites Demodex folliculorum and Demodex brevis.

OBJECTIVE

Our purpose was to compare the population density of Demodex mites in facial skin of defined categories of patients with rosacea with control subjects. We also assessed the impact of tetracycline therapy on the mite population.

METHODS

The population density and distribution of Demodex mites were studied in the facial skin of 42 patients with rosacea and 42 age- and sex-matched control subjects. Mites were counted in measured skin surface biopsy specimens obtained from six standard facial sites with cyanoacrylate glue.

RESULTS

The mean mite count was 49.8 (range 2 to 158) in patients with rosacea and 10.8 (range up to 97) in control subjects (p < 0.001); the highest density of mites was found on the cheeks. A statistically significant increase in mites was found in all subgroups of rosacea, being most marked in those with steroid-induced rosacea. Mite counts in patients with rosacea before and after a 1-month course of oral tetracycline showed no significant difference.

CONCLUSION

Increased mites may play a part in the pathogenesis of rosacea by provoking inflammatory or allergic reactions, by mechanical blockage of follicles, or by acting as vectors for microorganisms.

Hypertensive retinopathy: a cause of decreased visual acuity in children

Hypertensive retinopathy may present atypically in children. Delays in diagnosis may result in permanent visual loss, as demonstrated in three cases we saw.

Intermittent downbeat nystagmus secondary to vermian arachnoid cyst with associated obstructive hydrocephalus

A 27-year-old man presented with a history of dizziness and intermittent vertical oscillopsia after oblique extension of the head and neck, following a neck injury 2 years previously. He had no other symptoms of cerebellar or brainstem dysfunction. On examination, an intermittent downbeat nystagmus lasting about fifty seconds was elicited by head extension and rotation. Radiologic examination showed slight lateral instability of the odontoid on lateral rotation, and computed tomography brain scan with Iopamidol 300 (Niopam) contrast revealed a 5-cm vermian arachnoid cyst in the posterior fossa with obstructive hydrocephalus. Removal of the cyst cured the nystagmus.

Effect of anaesthesia on intraocular blood flow

Pulsatile ocular blood flow, intraocular pressure, systemic blood pressure, and heart rate was measured in two groups of 15 patients. One received lignocaine 1.5 mg/kg intravenously prior to induction. There was a significant increase in intraocular pressure after suxamethonium, which was not associated with any rise in ocular blood flow. Both the IOP and ocular blood flow increased significantly after tracheal intubation. A rise in ocular blood flow reflects the stress response associated with intubation. Lignocaine failed to attenuate either response.

Electroretinography, retinal ischaemia and carotid artery disease

Reduction in the amplitude of oscillatory potential (OP) on the B wave of an electroretinogram (ERG) is a sensitive index of experimental retinal ischaemia and is being used clinically to evaluate the progression of diabetic retinopathy. This study assessed whether electroretinography could detect retinal ischaemia in a group of patients with normal fluorescein angiograms and carotid atherosclerosis. Two groups of patients were studied. Group A (n = 15) had carotid atherosclerosis on duplex ultrasonography while a matched control group B (n = 15) had normal vessels. All patients in Group A had flurorescein angiograms. ERGs were recorded bilaterally using a Ganzfeld stimulator and Medelec oscilloscope. The OP amplitudes were determined using the peak-nadir method. Of the 60 eyes examined, 18 had abnormal OPs and all of these occurred in Group A; ten associated with ipsilateral non-stenosing carotid lesions and eight with critical stenoses. Twelve had normal OPs in Group A, only one of which was associated with severe disease. The mean OP amplitudes were 292 mu and 198 mu in Group A and 172.89 mu and 115.6 mu in Group B (P less than 0.005 Wilcoxon Rank Sum Test). (Two readings reflect Medelec readings before and after computer adjustments.) This study demonstrates by electroretinography significant retinal ischaemia in the presence of normal fluorescein angiography in patients with proven carotid artery disease. Further evaluation is required to determine the relative importance of flow reduction and silent micro-embolisation in the genesis of this ischaemia particularly in relation to pre- and postoperative evaluation.

Yersinia-induced uveitis in Ireland

A prospective study was undertaken on 54 patients with an apparently idiopathic first attack of acute anterior uveitis. Blood samples were assayed for antibodies to Yersinia enterocolitica and Yersinia pseudotuberculosis, and tested for HLA type. Thirteen patients were found to have serological evidence of recent yersinia infection, eight with Y. enterocolitica and five with Y. pseudotuberculosis. The clinical course of uveitis did not differ from that typically found in HLA-B27 positive patients. Five patients were observed to develop non-ocular inflammation at a variable interval. The means by which eye inflammation follows yersinia infection is discussed in the light of recent theories on pathogenesis of HLA-B27 associated diseases.

Retinal ultrastructural findings in cone degeneration

We studied an eye from a 73-year-old man with a sporadic type of retinal cone degeneration and choroidal melanoma. Histologic and ultrastructural studies of the nasal retina unaffected by the choroidal melanoma showed alterations at the outer retina predominantly involving the photoreceptors and retinal pigment epithelium. A wide spectrum of pathologic changes were observed, ranging from near normal retina showing only photoreceptor outer segment disease (distortion and kinking) to grossly pathologic regions where photoreceptor cell bodies were sparse and their outer segments absent. The retinal pigment epithelium in minimally affected regions of the retina showed an increased proportion of the melanin complement of the cell within complex granules. In severe disease, many cells showed only giant complex granules with no free melanin. Retinal pigment epithelial cell migration and relocation around blood vessels was also noted in severe disease.

Management of intraocular pressure during cardiopulmonary bypass

Intraocular pressure was measured in two groups of patients undergoing cardiopulmonary bypass surgery. A control group received mannitol at the start of bypass in accordance with standard practice; pressure was found to rise by 6.4 mmHg. In a second group of patients mannitol was administered 30 min prior to bypass; pressure elevation of 2.4 mmHg was found. These findings are discussed in relation to other clinical observations during bypass and to ocular morbidity complicating bypass surgery.