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Biomedical subjects

M J Lavin

Publications and source records attributed to M J Lavin.

34 records · Page 2Linked to original sources
PubMed1989

Glaucoma drainage tubes--their role in glaucoma management.

The results are presented from 100 eyes operated upon with either the ACTSEB procedure or a one piece tube and plate that have been followed for greater than 12 months. An intraocular pressure control was considered 'successful' if less than 21 mm Hg. The success varied according to the diagnostic category and its type of operation. One third of the total group did not require antiglaucomatous medications. Higher success rates were found in the one piece than the ACTSEB procedure. Overall success rates at 18 months per diagnostic group ranged between 41% in the neovascular glaucomas to 83% in the chronic simple glaucomas.

Adolescent↗
PubMed1989

Silicone tubes in glaucoma surgery: the effect of technical modifications on early postoperative intraocular pressures and complications.

One hundred and nineteen eyes with glaucoma were treated by implantation of silicone rubber tubes draining either to encircling inverted gutters (92 eyes) or to integral plates sutured at the equator of the globe. The occurrence of persistent choroidal effusion was related significantly (S less than 0.01) to post-operative hypotony and choroidal haemorrhage appeared to occur during periods of ocular hypotony. This paper describes our surgical modifications to overcome these problems. A one-piece integral tube and plate with a slit-valve mechanism designed to regulate post-operative intraocular pressure had a very variable response in 27 eyes, with mean pressures similar to those after unligated tube and gutters. Ligation of the tube in 34 eyes caused significantly higher mean intraocular pressures on the first two days after surgery than that in 43 eyes without ligation and the incidence of ocular hypotony (less than 7 mmHg) was significantly lower after ligation. However, five eyes with ligated tubes required operative release of the suture because of uncontrollably raised intraocular pressures. Venting of the drainage tube on the anterior chamber side of the occlusive ligation in 15 eyes caused fewer cases of raised post-operative intraocular pressures, but also a moderate increase in the frequency of ocular hypotony. At present a combination of occlusive ligation and a venting stab into the drainage tube in a one-piece tube and plate system appears to be the best design for avoiding short-term ocular hypotony whilst achieving long-term pressure control.

Adolescent↗
PubMed1987

The Hudson-Stahli line. I: An epidemiological study.

The overall prevalence of Hudson-Stahli line in a group of 550 subjects was 65 per cent with bilateral involvement and a further 4 per cent with unilateral involvement; analysis of two subgroups, with either blue/grey iris colour or with brown/green colour, suggested that the incidence is slightly higher in the latter group, particularly in the third to fifth decades. Irrespective of iris colour, the incidence rises with age. Both the length and the density of the line increase with age. For a given age, brown/green eyes have longer lines than blue/green eyes, but similar densities. Concordance of length and density between the right and left eyes of a pair is seen in about 80 per cent of subjects.

Adolescent↗
PubMed1987

The Hudson-Stahli line. II: A comparison of properties in eyes with and without long-term contact lens wear.

The eyes of 98 long-term contact lens wearers and 342 subjects not wearing contact lenses were examined for the presence of Hudson-Stahli lines, using slit-lamp biomicroscopy. The period of contact lens wear ranged from 2 to 25 years, all subjects using contact lenses for refractive reasons only. The incidence of Hudson-Stahli lines in contact lens wearers was not significantly different from that of control subjects in the same decades. Contact lenses appear, however, variably to alter the characteristics of the Hudson-Stahli line. Results from a group of 4 unilateral lens wearers, from 94 bilateral lens wearers and from studies of the morphology of the line suggest that contact lens wear is associated with a relative reduction of length and density of the line and also with a broadening and, more rarely, displacement of it. In eyes with brown or green irides, the attenuation of length and density by contact lens wear obscures the normal increases seen with age; in this subgroup of contact lens wearers, both factors appear to be almost constant from the third to sixth decades of life.

Adolescent↗
PubMed1987

The Hudson-Stahli line. III: Observations on morphology, a critical review of aetiology and a unified theory for the formation of iron lines of the corneal epithelium.

Observations as to the morphology, position and orientation of the Hudson-Stahli line are presented, based on the slit-lamp biomicroscopic examination of the eyes of six hundred and forty-four subjects. The origin of the pigments in the Hudson-Stahli zone and other corneal epithelial lines is reviewed, the evidence for either tear film dynamics or epithelial dynamics influencing the typical configuration is discussed and a unified theory for the formation of corneal iron lines is presented.

Cornea↗
PubMed1987

Cyclic variation in onset of central retinal vein occlusion.

We studied the seasonal incidence of onset of symptoms of central retinal vein occlusion (CRVO) in 105 patients over a 5-year period. Their onset showed a significant cyclic variation (p less than 0.01), being most frequent in the months September through to February. We believe this seasonal variation may in part reflect seasonal changes in haemostasis and retinal perfusion, though other unidentified factors play a significant role.

Humans↗
PubMed1987

Retinal arterial macroaneurysms: a retrospective study of 40 patients.

We studied 40 patients with a total of 44 retinal arterial macroaneurysms. All patients were followed up for at least six months. Macroaneurysms (MAs) have variable clinical presentations and are still frequently misdiagnosed before fluorescein angiography. Haemorrhagic MAs were most frequently misdiagnosed (75%), and had a sudden onset with a relatively poor visual outcome. Patients with these MAs had higher systolic blood pressures and significantly fewer associated retinal vein occlusions (p less than 0.05) than other types of MA. Exudative MAs caused a gradual onset of symptoms, were frequently associated with retinal vein occlusions, and were the most frequent indication for laser treatment. Only one of 10 quiescent MAs subsequently developed significant exudation or haemorrhage. We confirm the association of MAs with retinal and systemic vascular disease. In addition we found that MA patients had a significantly higher blood packed cell volume (haematocrit) than controls (p less than 0.05). Laser treatment significantly shortened the duration of MA patency (p = 0.006).

Aged↗
PubMed1986

Is topical haloperidol a useful glaucoma treatment?

A randomised, double blind, single dose study of topical haloperidol, a dopamine receptor blocking drug, was performed on 20 healthy volunteers. After its administration a modest reduction in intraocular pressure was recorded over the six-hour study period, but the difference was not significant at the p less than 0.05 level. Although dopamine blocking agents are effective in reducing intraocular pressure in experimental animals, topical haloperidol appears unlikely to be clinically useful in the treatment of glaucoma.

Administration, Topical↗
PubMed1986

Pathogenesis of recurrent corneal erosion: a further aetiological factor?

An unmasked, prospective study of the magnitude of Bell's phenomenon in 42 patients with recurrent corneal epithelial erosion has demonstrated an abnormally high prevalence of 'absent' or 'weak' Bell's phenomenon as compared to that in a control group of 189 patients. Those patients without a predisposing factor had a 78 per cent prevalence of abnormal Bell's phenomenon, those with an epithelial or basement membrane dystrophy had a 55 per cent prevalence, whereas those with preceding traumatic corneal abrasion formed an intermediate group (62 per cent abnormal Bell's phenomenon); the prevalence of 'absent' or 'weak' Bell's phenomenon in the control group was 26 per cent. The probable mechanisms of recurrent corneal epithelial erosion are discussed in the light of this newly described association.

Adult↗
PubMedDate not supplied

Techniques of intraocular lens suspension in the absence of capsular/zonular support.

Implantation of intraocular lenses has become the standard of care in the aphakic state. Ideally, the lens is placed in the capsular bag, which affords stable fixation at a position closest to the nodal point of the eye. However, there will always be instances where this will not be possible. Congenital weakness of the lens zonules in various conditions, trauma, and surgical complications of cataract surgery are just some examples. In this article, we review the methods that have been devised to allow intraocular lens implantation in the absence of capsular or zonular support. These include anterior chamber angle and iris-fixated lenses, as well as posterior chamber iris- and scleral-sutured lenses. The various lenses are described, and the techniques involved, advantages and disadvantages, complications, and results of each method are discussed. It is hoped that this article will provide a comprehensive overview of ways to deal with a problem that can still result in a very good visual outcome for the patient. This is particularly relevant given the many recent developments and refinements of methods in implanting intraocular lenses.

Humans↗