Posterior capsule opacification following diabetic extracapsular cataract extraction

Review was performed of extracapsular cataract extraction with posterior chamber lens implantation in 90 diabetic patients and 263 non-diabetic patients. There was a higher incidence of posterior capsular opacification as judged by the requirement for Nd:YAG posterior capsulotomy in patients with non-proliferative (12/35, 34%) or quiescent proliferative diabetic retinopathy (8/18, 44%) than in non-diabetic patients (48/263, 18%) (Mantel-Haenszel p = 0.04). Although subgroup analysis showed a higher incidence of posterior capsule opacification in diabetics with non-proliferative or quiescent proliferative retinopathy than in diabetics without retinopathy, this was not statistically significant (Mantel-Haenszel p = 0.19 and p = 0.07, respectively). Following cataract surgery in diabetics with retinopathy, frequent review and prompt management of posterior capsular opacification is recommended, to maintain adequate fundus visualisation at a time when deterioration of retinopathy is likely.

Adult Coats' disease in branch retinal vein occlusion

We report a case of adult Coats disease secondary to a branch retinal vein occlusion. Angiograms show the relationship of the peripheral telangiectasis, aneurysm formation and vascular incompetence to the peripheral retinal ischaemia. The possible role of vascular remodelling in the pathogenesis of this uncommon complication of a common condition is discussed.

Color contrast sensitivity and pattern electroretinographic findings after diode and argon laser photocoagulation in diabetic retinopathy

The retinal depth at which photocoagulation is maximal varies with wavelength. We compared visual function of eyes undergoing photocoagulation by the near-infrared diode laser to the argon green laser. We treated 14 patients with diabetic retinopathy requiring bilateral panretinal photocoagulation with the diode laser on the right eye and the argon system on the left eye. Before and after treatment visual acuity, central and peripheral color contrast sensitivity, and pattern electroretinograms were recorded. No difference was noted in the clinical response or visual acuity outcome, but a tendency was observed for less decline in color contrast sensitivity and pattern electroretinogram recordings after diode laser photocoagulation. Although P values (.05 to .5) did not reach significance, a mean of 8.4 of 14 patients per test had better test results after diode laser treatment. Diode laser photocoagulation seems to be a viable alternative to argon laser treatment and may be a more gentle mode of treatment.

Immunofluorescence analysis of B-1 cell ontogeny in the mouse

In order to further understand the developmental aspects of B-1 cells, we characterized the ontogeny of this B cell population in the spleen and peritoneal cavity of BALB/c mice. Although there are B-1 cells in the spleen within the first 1-3 weeks after birth, they do not at any stage represent the majority of splenic B cells. Splenic B-1 cells reach peak levels at approximately 9 days after birth. The mesenteric lining that covers the small intestine of 7-day-old mice contains a population of IgM+ B cells, while at the same age, there are few lymphoid cells in the peritoneal cavity. Between 7 and 8 days after birth there is an influx of B cells into the peritoneal cavity. At 8 days, the first detectable peritoneal B cells appear to be of the B-1 type based on expression of IL-5 receptor and CD5. However, these peritoneal B-1 cells do not express Mac-1. This antigen is not expressed by the majority of peritoneal B-1 cells until 3 weeks. This study indicates that the majority of early splenic B cells are not B-1 cells and it suggests that the mesenteric tissues surrounding the gut contain B lymphocytes which traffic into the peritoneal cavity where they then reside.

Effects of IgM allotype suppression on serum IgM levels, B-1 and B-2 cells, and antibody responses in allotype heterozygous F1 mice

IgM allotype heterozygous F1 mice were independently suppressed for Igh6a or Igh6b to evaluate the contribution of B-1 and B-2 cells to natural serum IgM levels and Ab responses. B-2 B cells expressing IgM of the suppressed allotype were evident in the spleens of suppressed mice 4 to 6 weeks after cessation of the suppression regimen, whereas B-1 B cells of the suppressed allotype were undetectable for up to 9 months. Although serum IgM of the suppressed allotype was initially depleted in mice suppressed for either allotype, by 7 months of age, there were detectable levels of IgM of the suppressed allotype in the serum; however, the levels were significantly below that found in nonsuppressed mice. When mice were immunized with either the T-independent or T-dependent form of phosphorylcholine, those suppressed for either allotype, and consequently depleted of B-1 B cells of that allotype, did not respond with phosphorylcholine-specific IgM of the suppressed allotype. In contrast, when mice were immunized with alpha 1-3 dextran, the Igh6a allotype-suppressed mice were able to produce dextran-specific IgM of that allotype. These results show that allotype-bearing B-1 cells of both allotypes can be effectively suppressed by this suppression protocol and this produces long-lasting effects on B-1 cell levels and serum IgM of the suppressed allotype. These observations reflect the derivation of the majority of B-1 cells from fetal-neonatal precursors, which cannot be replaced by newly emerging B-2 cells of adult origin. Their ablation by antibody treatment results in permanent alterations to the adult B-cell repertoire.

Orbital ultrasound in the ocular ischaemic syndrome

The ocular ischaemic syndrome illustrates well the effects of hypoperfusion of the globe and is a useful model for studying disorders of the orbital circulation. Recent advances in orbital ultrasound techniques have provided a non-invasive method of examining flow velocities in the orbital vessels, particularly the ophthalmic artery. Orbital ultrasound studies were performed on 3 cases of the ocular ischaemic syndrome. Continuous or intermittent reversal of blood flow in the ophthalmic artery was seen in all cases. How this phenomenon relates to the symptoms and signs in affected patients, and the role of orbital ultrasound in the investigation of the ocular ischaemic syndrome, are discussed.

No-needle one-quadrant sub-tenon anaesthesia for panretinal photocoagulation

Panretinal photocoagulation (PRP) is tolerated well by most patients using topical anaesthesia alone, though there are a significant number of patients who experience pain. Additional local anaesthesia alternatives for these patients include retrobulbar, peribulbar or subconjunctival injection. Deep introduction of a sharp needle may rarely cause damage to orbital structures, whereas no-needle sub-Tenon irrigation of local anaesthetic solution to the posterior Tenon's space theoretically avoids these risks. A one-quadrant, inferior-nasal, sub-Tenon delivery of 1.5-2 ml plain 2% lignocaine was administered and PRP performed on 12 eyes of 12 patients who were previously intolerant of PRP by topical anaesthesia alone. To assess the efficacy of anaesthesia, patients were asked to score pain, using a visual analogue score chart graded from 0 to 10. If patients were unable to see the chart, or read the accompanying text, a verbal explanation and description of the scoring chart was performed. Where PRP was performed with topical amethocaine 1% alone, pain scores were graded as median 8, mean 8.5 and range 6-10. The administration of sub-Tenon anaesthesia was well tolerated with a median pain score of 1.5, mean 1.9 and range 0-5. PRP after sub-Tenon administration was successfully completed in 11 of the 12 patients with a median pain score of 1.5, mean 1.8 and range of 0-9. The range was wide due to one patient with a high pain score who was intolerant of PRP in spite of the sub-Tenon delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term follow-up of diode laser trabeculoplasty for primary open-angle glaucoma and ocular hypertension

BACKGROUND

Initial studies of laser trabeculoplasty using infrared energy (810 nm) emitted by diode semi-conductor lasers have been encouraging. A 2-year study of diode laser trabeculoplasty (DLT) in the control of primary open-angle glaucoma (POAG) and ocular hypertension has been completed.

METHODS

Patients with uncontrolled POAG or ocular hypertension were treated with DLT to one half of the trabecular meshwork using a trabeculoplasty lens. Spot size was 100 microns, exposure time was 0.2 second, and mean power was 1096 mW (+/- 46.5 mW). The desired endpoint was a mild blanching of the meshwork only.

RESULTS

Twenty-five eyes of 16 patients were treated. Mean intraocular pressure reduction was 9.24 mmHg (+/- 3.4 mmHg) at 6 weeks, 9.32 mmHg (+/- 3.6 mmHg) at 3 months, 9.34 mmHg (+/- 3.8 mmHg) at 6 months, 8.42 mmHg (+/- 2.62 mmHg) at 12 months, 8.14 mmHg (+/- 3.42 mmHg) at 18 months, and 7.9 mmHg (+/- 3.63 mmHg) at 24 months. No pressure peaks (> 5 mmHg) were recorded after therapy. Inflammation and discomfort were minimal after laser treatment. Of 16 eyes examined at 2 years, there were no peripheral anterior synechiae. During the course of the study, six eyes became uncontrolled, despite one session of DLT. Four eyes regained control with a further session of DLT, but two required trabeculectomy.

CONCLUSION

Diode laser trabeculoplasty is an effective form of therapy in POAG and ocular hypertension. Hypotensive effects and success rates are comparable with argon laser trabeculoplasty (ALT). Reduced inflammation after laser treatment may be due to reduced absorption of infrared energy by the melanin of the anterior segment. The portable nature of these lasers may allow for laser delivery in developing countries and remote situations.

[Comparative use of diode and argon laser for panretinal photocoagulation in diabetic retinopathy]

The recently introduced semiconductor diode laser is portable, more compact, and cheaper to maintain than other laser systems. It is unclear whether its wavelength characteristics in the near infrared (810 nm) lead to different clinical results of retinal photocoagulation. In a prospective study ten diabetics (3 type I and 7 type II) ranging in age from 26 to 72 years with bilateral proliferative or severe nonproliferative diabetic retinopathy and visual acuity better than 6/18 in both eyes underwent panretinal photocoagulation. One eye was treated with the diode laser, the fellow eye with argon green (514 nm). Follow-up was documented by best-corrected visual acuity, fundus photography and fluorescein angiography. Mean duration of follow-up was 12 months. In neither group was there a significant difference in the response of retinopathy and neovascularization to the treatment, or in the course of visual acuity. Fluorescein angiography revealed the more profound effects of the diode laser in the choroid. Compared to argon laser treatment, patients found diode laser treatment more painful, but appreciated the absence of bright flashes during therapy. Photocoagulation for diabetic retinopathy using the diode laser was as effective as using the argon system in this initial pilot study.

Displaced intraocular lens repositioning using a reversed 10-0 straight polypropylene needle lasso technique

Images

Photocoagulation of choroidal neovascular membranes with a diode laser

Nine eyes with parafoveal choroidal neovascular membranes due to age-related macular degeneration or angioid streaks were treated with a diode laser and were followed up to 40 weeks (mean 26 weeks). Angiographically proved closure of the membrane was achieved in seven eyes. Four lesions needed a second treatment for growth of subretinal neovascular tissue. Post-treatment visual acuity ranged from 6/9 to 6/60. Two eyes developed subfoveal membranes resulting in poor visual acuity. The morphology of the diode laser lesions differed from that of the argon green laser and was more similar to that of the krypton laser, producing a 'black hole' on the fluorescein positive print. In one particular eye fluorescein angiography revealed subfoveal choroidal non-perfusion next to the site of the diode lesion suggesting choroidal vascular closure.

Factors influencing the natural history of diabetic retinopathy

Despite recent improvements in the management of blood glucose control and in modern technology such as laser treatment and vitreoretinal surgery, diabetes mellitus is the major systemic cause of blindness in the Western world. The study of the natural history of diabetic retinopathy is difficult because of the variability of the disease, and the numerous factors that may influence its course and outcome. In the many studies available of the natural history of diabetic retinopathy, there is a failure to identify these factors. This article tries to identify and to classify the influences that may modify the outcome and the natural course of diabetic retinopathy, and gives some advice on how to deal with them. They can be subdivided into external, internal and ocular factors. Any future studies of the natural history of diabetic retinopathy are marred by the fact that effective treatment is now established and the guidelines for when to commence treatment and the techniques of treatment are well documented.

Encephalitis and chorioretinitis associated with neurotropic African horsesickness virus infection in laboratory workers. Part II. Ophthalmological findings

Four laboratory workers developed uveitis-chorioretinitis, associated with encephalitis in 3 cases. The retinitis was characterised by haemorrhages and areas of retinal oedema, most marked over the posterior polar regions, and was associated with exudative retinal detachments. The lesions progressed over weeks and showed a severe retinal arterial vasculopathy with arteriolar narrowing, ghost vessel formation and the development of optic atrophy. The picture in 2 of the patients resembled that of the acute retinal necrosis syndrome (ARN). Antibodies to African horsesickness (AHS) virus were detected. The serology for AHS virus was positive in all 4 patients as well as in 5 of 15 laboratory workers from the same facility who were clinically and ophthalmologically normal. This is to our knowledge the first description of subclinical and probable clinical neurotropic AHS virus infection in man. AHS is a hitherto-unrecognised possible cause of viral retinitis and the ARN syndrome.

Transient vessel wall sheathing in acute retinal vein occlusions

Three cases are reported which had features similar to, and evolved in a pattern consistent with central retinal vein occlusions and a fourth case is reported which behaved as a hemispheric vein occlusion. However, they differed from classic retinal vein occlusions by having prominent sheathing of the retinal venous vasculature at presentation, which in all four cases resolved within three weeks. There was no evidence for any of these cases having an inflammatory vasculitis. The significance of this transient sheathing is uncertain.

Extracapsular cataract extraction in diabetics with rubeosis iridis

We reviewed thirteen operated eyes (twelve diabetic patients) with rubeosis iridis who underwent extracapsular cataract extraction and intraocular lens implantation. Prior to surgery five had active proliferative retinopathy (APR), and eight had non-proliferative retinopathy (NPR), either quiescent proliferative retinopathy (QPR) or background retinopathy (BR). No case with APR was visually improved by surgery. Three cases with NPR achieved a visual acuity of 6/12. After surgery, vitreous haemorrhage or progression of proliferative retinopathy occurred in three cases with APR. Early postoperative fibrinous uveitis was severe in eyes with APR, resulting in permanent fibrin membrane formation in four. We suggest a significant prognostic indicator in diabetic cataract extraction with rubeosis iridis is the status of the underlying retinopathy. With NPR, postoperative visual acuity may be good and early postoperative complications less severe. In the presence of APR the visual outcome is poor, progression of retinopathy likely and early postoperative fibrinous uveitis may be severe enough to prevent postoperative panretinal photocoagulation. Maximum preoperative panretinal ablation is essential in these cases.

Macular oedema and retinal neovascularisation in juvenile diabetics

Thirteen young diabetic patients with peripheral capillary non perfusion who presented with symptoms of mild maculopathy were reviewed retrospectively. In this group, peripheral retinal ischaemia was often overlooked and a rapidly progressive proliferative retinopathy developed. Fluorescein angiography of the peripheral retina showed capillary closure, but with preservation of arterioles and venules. In this series, half of the eyes lost vision. In seven eyes where the peripheral ischaemia was treated by pan retinal photocoagulation, the maculopathy resolved without any specific laser treatment to the macula. In young diabetics presenting with maculopathy, the peripheral retina should be examined for ischaemia, and if present, pan retinal laser photocoagulation should be performed. Focal treatment for the macular disease can be delayed until after the peripheral photocoagulation, as the maculopathy may remit.

Detection of subpigment epithelial neovascularisation in cases of retinal pigment epithelial detachments: a review of the Moorfields treatment trial

The entry angiograms of 42 eyes with detachment of the retinal pigment epithelium in a treatment trial of laser photocoagulation were reviewed in a masked fashion by three observers in order to assess the possible presence of subpigment epithelial neovascularisation. Vascularity or avascularity was designated with reference to a list of clues believed to imply the presence of subpigment epithelial neovascularisation. As a predictor of outcome the initial assessment achieved a sensitivity and specificity of 77% and 82% respectively. Despite notable parity of the degree of sensitivity and specificity among the three observers, full agreement on the initial assessments was reached in only 23 eyes (55%), 10 with vascular and 13 with avascular outcome. Of these, only one eye which developed new vessels after 4 years had an outcome which differed from that predicted by classification of the entry angiograms.

Controlled trial of laser photocoagulation of pigment epithelial detachments in the elderly: 4 year review

Patients who were enrolled in a controlled treatment trial of laser grid photocoagulation for retinal pigment epithelial detachment as part of age-related maculopathy were reviewed 4 years after entry into the trial. The data imply that the original conclusion that this form of treatment did not improve the visual prognosis at 18 months was also justified at 4 years. It has become clear that lesions with evidence of subpigment epithelial new vessels were included in the trial. In a retrospective study the lesions were separated into those in which there was evidence of subretinal neovascularisation and those in which no such evidence existed. A difference was identified in the behaviour of the treated and untreated lesions designated avascular in that the treated eyes had a poorer visual outcome. These cases accounted for the different behaviour between two management groups in the initial study such that the original conclusion that grid photocoagulation of avascular pigment epithelial detachments in the elderly does not improve the visual prognosis is justified.

Development and function of the early B cell repertoire

The early B cell repertoire is characterized by extensive interconnectivity, autoreactivity and multispecificity. Our preliminary sequence analysis of some of the idiotype specific antibodies is beginning to provide molecular clues to explain the observed multireactivity and the expression of shared idiotypic determinants on immunoglobulins of early B cells. The VH gene rearrangements analyzed are typical of the early pre-B cell and CD5 B cell repertoire. Some of these include shared or identical CDR3 regions resulting from the use of germline VH, D and JH gene segments in the absence of N region addition. As previously described, the most D proximal VH genes are also used most frequently. Collectively these genetic restrictions, together with the lack of somatic mutation, suggest that the characteristic self reactivity of the early B cell repertoire is related to the expression of germline gene segments and limited use of diversification mechanisms. It has also been possible for the first time to isolate hybridomas secreting functional IgM molecules which use the most D proximal VH gene, VH81X. These antibodies and another example from the VH7183 family have a broad multireactivity pattern possibly because of the presence of an unusually high number of charged amino acid groups present in the VH region. These findings are preliminary and more extensive studies are needed to establish if these groups are responsible for the highly cross-reactive nature of these antibodies. Nevertheless, these unusual characteristics signify a unique role for antibodies expressing this VH gene during B cell development. It is also clear that the observed anti-lymphocyte reactivity, another feature of the newborn repertoire, is the result of the prevalence of B cells using similar if not identical VHDJH genes and DJH joins. The development of these B cells appears to occur consistently in early ontogeny and, again, are not found in conventional splenic B cells obtained from the normal adult. Understanding the functional significance of the early appearance of these antibodies may help to clarify and understand their role during development as well as in autoimmunity. We propose that the unique self reactive nature of the early repertoire provides a pattern within which self-assertiveness develops and results in the establishment of the adult repertoire. In doing so, dominant clones are established which may or may not be within, but whose selection and differentiation is directed by the CD5 B cell subset.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute tear of the retinal pigment epithelium

The fluorescein angiographic findings immediately following a tear of the retinal pigment epithelium are presented and the mechanisms of fluid movement from the retina to the choroid are discussed. Our case represents a clinical correlate to recent experimental reports on fluid movement across the retinal pigment epithelium-Bruch's membrane complex.

Effect of a long-acting somatostatin analogue (BIM23014) on proliferative diabetic retinopathy: a pilot study

A pilot study on the use of a continuous infusion of somatostatin, by subcutaneous pumps in the management of proliferative diabetic retinopathy is reported. Two patients out of eight with proliferative retinopathy demonstrated improvement. One patient demonstrated regression of disc new vessels and the other a reduced area of retinal capillary non-perfusion, both demonstrated by fluorescein angiography. Control patients showed worsening of fluorescein leakage over the observation period of four to six weeks whereas the other six patients given the somatostatin infusion did not demonstrate any deterioration. The mechanism of action of somatostatin in this study is unknown but it is thought to have direct anti-angiogenic properties as well as inhibiting growth hormone secretion.

Iris clipping of a diode laser beam when performing retinal photocoagulation

The Microlase infrared diode laser has recently become available for retinal photocoagulation. It uses a laser beam with a large convergence angle (23 degrees). This gives rise to a laser beam with a relatively large cross section at the subject's pupil. In this study the pupillary area required to view the fundus at the slit-lamp with a 90-dioptre lens is determined. It is found that the pupillary area required to view the fundus is smaller than the cross section of the Microlase laser beam at the pupil. Thus iris clipping of the laser beam can occur even though the surgeon has a clear and bright view of the fundus. Care should be taken to use the Microlase only in the presence of a widely dilated pupil.

Effects of dibutyryl cyclic AMP, ouabain, and xanthine derivatives on crossbridge kinetics in rat cardiac muscle

In a previous communication, we showed that beta-adrenergic stimulation of cardiac muscles was associated with an increase in the rate of cycling of crossbridges as measured by perturbation analysis in the frequency domain. In this analysis, the frequency at which dynamic stiffness is a minimum (fmin) is taken as a measure of the rate of crossbridge cycling. In this paper, we test the hypothesis that the beta-adrenergic receptor-induced increase in crossbridge cycling rate is mediated by elevation of the intracellular level of cyclic AMP. The approach taken is to compare the effects on fmin in rat papillary muscles during Ba(2+)-activated contractures of 1) an agonist of cyclic AMP that can easily penetrate the cell, namely, dibutyryl cyclic AMP, 2) agents that block cyclic AMP phosphodiesterase, namely, the xanthine derivatives isobutylmethylxanthine and caffeine, and 3) an inotropic agent that does not affect the intracellular level of cyclic AMP, namely, ouabain. Our results showed that dibutyryl cyclic AMP at a dose of 5 mM has the same actions as beta-adrenergic stimulation: it potentiated the isometric twitch force, reduced the time to peak tension and time to half relaxation, and shifted fmin by a factor of 1.8 +/- 0.1 (n = 5). Isobutylmethylxanthine at up to 1.1 mM also acted in the same manner, increasing fmin by a factor of 1.8 +/- 0.2 (n = 6), but ouabain, at a dose (0.03 mM) sufficient to potentiate twitch force by 40 +/- 2% (n = 4), was without effect on the time course of the twitch nor was fmin changed (n = 4). Our findings support the hypothesis that a beta-adrenergic receptor-mediated increase in crossbridge cycling rate is due to an increase in intracellular cyclic AMP level and illustrate the usefulness of the frequency domain analysis approach in the analysis of the mechanism of action of inotropic agents.