Refractive lens exchange in high myopia: long term follow up

AIM

To establish long term outcomes and incidence of complications following refractive lens exchange (RLE) for the correction of high myopia.

METHODS

Operative and postoperative records of 62 cases of small incision phacoemulsification RLE performed in 37 patients over an 11 year period, by a single surgeon, were reviewed. In addition, patients were recalled for a follow up examination, which included dilated retinal examination with scleral indentation.

RESULTS

Two cases (3.2%) of retinal detachment occurred at intervals of 2 months and 5 months following uncomplicated RLE procedures. A posterior chamber intraocular lens was inserted in 46 eyes (74%). YAG laser posterior capsulotomy was performed in 38 of 62 eyes (61%) and did not represent a risk for retinal detachment.

CONCLUSION

Refractive lens exchange results in rapid and predictable improvement in unaided vision in patients with high myopia. However, the risks of sight threatening complications inherent in any intraocular procedure underlie the need for appropriate patient selection.

Investigation and management of an epidemic of Hydroview intraocular lens opacification

BACKGROUND

Opacification of Hydroview posterior chamber intraocular lenses had been prescribed, but many aspects of this complication remain unknown, including its aetiology, clinical features, pathogenesis, prognosis and treatment. This paper describes an epidemic of Hydroview intraocular lens (IOL) opacification.

METHODS

Subjects in whom the Hydroview IOL was implanted were recalled for evaluation of its transparency, assessment of contrast sensitivity (CS) [VCTS (Vistech CO, Dayton, Ohio, USA)] and visual acuity (LogMAR), and analysis of medical and surgical data. The results of IOL exchange in 69 eyes of 67 patients are also presented.

RESULTS

Of 103 patients recalled, 46 (44.6%) and 3 (2.9%) exhibited opacification of the implanted IOL in one and both eyes, respectively. CS was significantly worse in the presence of an opacified IOL (P<0.050), even when Snellen acuity was unaffected. Where the viscoelastic employed during the primary cataract surgery was reliably documented, VISCOAT was used in 100% of cases (43/43), whereas Healonid had not been used in any (0/57) (P<0.0001). Following IOL exchange, visual acuity improved from a mean (+/-SD) of 0.75 (0.41) to 0.4 (0.34) LogMAR.

CONCLUSIONS

The prevalence of Hydroview IOL opacification is associated with the use of VISCOAT in the primary cataract surgery, and there is a biochemically plausible rationale to account for this. Visual acuity and contrast sensitivity are adversely affected by opacification of the Hydroview IOL, but CS to a greater extent. Exchange of opaque IOLs is a visually rewarding procedure.

A novel index for predicting intraocular pressure reduction following cataract surgery

AIM

The results of a study designed to investigate the predictive value of preoperative anterior chamber depth (ACD) and intraocular pressure (IOP) are reported. The relation between these factors and their effect on the reduction in IOP following phacoemulsification cataract surgery was also studied.

METHODS

The ACD and IOP were prospectively measured in 103 non-glaucomatous eyes of 103 patients who underwent uneventful phacoemulsification and posterior chamber intraocular lens (PCIOL) implantation. Other data which were recorded included best corrected visual acuity, axial length, lens thickness, and severity of lens opacity.

RESULTS

The ACD increased by a mean (SD) of 1.10 (0.44) mm (p<0.00001) and this increase was significantly and inversely related to preoperative ACD (r(2) = 68%; p<0.01). IOP dropped by a mean of 2.55 (1.78) mm Hg following cataract surgery (p<0.0001), and this reduction was significantly and positively related to preoperative IOP (r(2) = 56%; p<0.01), and significantly and inversely related to preoperative ACD (r(2) = 21%; p<0.01). A novel ratio, the pressure to depth (PD) ratio (preoperative IOP/preoperative ACD), was found to be significantly and positively related to the surgically induced reduction in IOP (r(2) = 73%; p<0.01), and IOP was reduced by > or =4 mm Hg in all patients with a PD ratio >7.

CONCLUSION

The reduction in IOP following cataract surgery was found to be positively related to preoperative IOP, and inversely related to preoperative ACD. Furthermore, these results indicate that a novel index, the PD ratio, is strongly predictive for IOP reduction following cataract extraction, and may prove useful in surgical decision making.

The influence of pharmacological mydriasis on biomicroscopic evaluation of the glaucomatous optic nerve head

AIMS

To investigate whether pharmacological mydriasis influences interobserver agreement or within-observer agreement (comparing estimates made before and after dilation) in the evaluation of the optic nerve head (ONH) of the glaucoma suspect or patient.

METHODS

Monoscopic disc photographs of the ONH were assessed by each observer on two separate occasions in order to establish baseline intra- and inter-observer agreement. Then the ONH of 53 eyes of 53 patients was examined by each observer on two separate occasions, the pupil being pharmacologically dilated on only one of these visits. Each observer commented on the vertical and horizontal cup-to-disc (C/D) ratio, and the presence of the following ONH parameters: laminar dots; disc haemorrhage; disc saucering; disc notching, and peripapillary atrophy (PPA).

RESULTS

Intersessional variability of C/D ratio estimates, based on photographs of the ONH, was similar for the two observers. The mean (+/-standard deviation) age of the 53 patients was 70 (+/-15) years, and the male : female ratio was 28 : 25. Intraobserver agreement of C/D ratio estimation performed through a dilated pupil on one occasion and an undilated pupil on the other occasion was not statistically different between observers. Interobserver agreement of C/D ratio estimates were not adversely affected in a statistically meaningful way if ONH evaluation was performed by each observer under conditions of nonmydriasis or by each observer under conditions of pharmacological mydriasis. Within-observer (before and after dilation) and interobserver agreement with respect to the presence of laminar dots (kappa=0.41-0.69), PPA (kappa=0.36-0.54), and pathological cupping (kappa=0.46-0.68) was typically moderate to good across the two visits where the pupil was dilated on one occasion only, but less reliable for saucering, disc notching and disc margin haemorrhage.

CONCLUSION

Routine pharmacological mydriasis is not essential for reproducible evaluation of the ONH for patients in whom a satisfactory view of the optic disc can be achieved through the undilated pupil.

Current concepts and recent advances in the management of age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness in the Western World in those aged 65 and older. At present, several treatment modalities are utilised and several more are undergoing investigation in an attempt to retard the occurrence and progression of this devastating condition.

AIMS

To provide the non-ophthalmologist with an understanding of the current treatment options available to patients suffering from all variants of AMD.

METHODS

Medline and Embase search.

RESULTS

Several treatment modalities have been investigated and utilised in the treatment of all variants of this condition. While promising results have been reported, no treatment is ideal.

CONCLUSION

While no curative treatment for this condition currently exists, early recognition and treatment, if indicated, have been shown to reduce the risk of severe vision loss in patients with this condition.

Macular translocation: unifying concepts, terminology, and classification

PURPOSE

To describe some unifying concepts, terminology, and classification of macular translocation so as to facilitate communication within the scientific community.

METHODS

A panel of ophthalmologists with expertise in macular translocation reviewed available data and developed some unifying concepts, terminology, and classification of macular translocation.

RESULTS

Macular translocation may be defined as any surgery that has a primary goal of relocating the central neurosensory retina or fovea intraoperatively or postoperatively specifically for the management of macular disease. It may be classified according to the size of the retinotomy and, where applicable, the technique of chorioscleral shortening used. The direction of macular translocation is denoted by the movement of the neurosensory macula relative to the underlying tissues. Effective macular translocation may be defined as successful intraoperative or postoperative relocation of the fovea overlying a subfoveal lesion to an area outside the border of the lesion. The concepts of minimum desired translocation and median postoperative foveal displacement can give some useful idea of the likelihood of effective macular translocation before surgery.

CONCLUSIONS

Use of a common standardized terminology for macular translocation will facilitate communication within the scientific community and enhance further research in this area. However, the definitions, terms, classification, and concepts concerning macular translocation are likely to continue to evolve as macular translocation undergoes further modifications and refinements.

Candida endophthalmitis: an unusual complication of prolonged intravenous access

A 16 year old boy awaiting a defunctioning colostomy for Crohn's disease complained of reduced vision in his left eye. Four weeks previously candida had been isolated from his central line used for parenteral feeds. Fundal examination of the left eye revealed a macular abscess with a classic "string of pearls" appearance of multiple vitreous abscesses. This was treated with pars plana vitrectomy and intravitreal antifungal therapy. Microbiological studies confirmed a diagnosis of candida endophthalmitis.

Macular pigment and risk for age-related macular degeneration in subjects from a Northern European population

PURPOSE

Age and advanced disease in the fellow eye are the two most important risk factors for age-related macular degeneration (AMD). In this study, the authors investigated the relationship between these variables and the optical density of macular pigment (MP) in a group of subjects from a northern European population.

METHODS

The optical density of MP was measured psychophysically in 46 subjects ranging in age from 21 to 81 years with healthy maculae and in 9 healthy eyes known to be at high-risk of AMD because of advanced disease in the fellow eye. Each eye in the latter group was matched with a control eye on the basis of variables believed to be associated with the optical density of MP (iris color, gender, smoking habits, age, and lens density).

RESULTS

There was an age-related decline in the optical density of macular pigment among volunteers with no ocular disease (right eye: r(2) = 0.29, P = 0.0006; left eye: r(2) = 0.29, P < 0.0001). Healthy eyes predisposed to AMD had significantly less MP than healthy eyes at no such risk (Wilcoxon's signed rank test: P = 0.015).

CONCLUSIONS

The two most important risk factors for AMD are associated with a relative absence of MP. These findings are consistent with the hypothesis that supplemental lutein and zeaxanthin may delay, avert, or modify the course of this disease.

Decompensation of a congenital retinal macrovessel with arteriovenous communications induced by repetitive rollercoaster rides

PURPOSE

To describe a congenital retinal venous macrovessel that communicates with a cilioretinal artery and a retinal artery, and to report how this vascular anomaly decompensated as a result of repetitive rollercoaster rides.

METHODS

Case report with serial fundus photography and fluorescein angiography.

RESULTS

After a short period of intensive rollercoaster rides, a 19-year-old woman complained of reduced vision in one eye. Funduscopy and fluorescein angiography revealed a venous congenital retinal macrovessel with arteriovenous communications, and retinal exudation was visible at the termination of the anomalous vessel. Exudation resolved, and acuity recovered after a period of avoidance of rollercoaster rides.

CONCLUSION

This case represents the first report of a retinal artery and a cilioretinal artery communicating with a congenital retinal macrovessel, and it suggests that such patients are at increased risk of retinal vascular decompensation if involved in activities associated with changes in g-forces, such as bungee jumping or rollercoaster rides.

Non-organic visual loss in children

BACKGROUND

Patients with non-organic visual loss (NOVL) can take up a disproportionate amount of clinic time and clinicians often resort to expensive and prolonged investigations to ensure the correct diagnosis. This is especially the case in children.

METHODS

The case notes of 30 children (18 girls, 12 boys) were retrospectively reviewed following presentation with a primary complaint of visual impairment and a diagnosis of non-organic visual loss. This figure represents 1% of new paediatric referrals to our unit. Associated symptoms included headache, periorbital pain, diplopia, photopsia and photophobia. Visual field defects were present in 5 patients and spasm of the near reflex in 1 child.

RESULTS

Treatment consisted of reassurance and was associated with recovery of normal visual function in all cases. Three children were referred to other health care professionals. All psychophysical, electrophysiological and neuroradiological investigations were negative.

CONCLUSION

Our study shows that non-organic visual loss is relatively common in pre-pubertal children and that this condition can be safely diagnosed using standard clinical tests in the majority of cases. Prompt diagnosis prevents unnecessary investigations and prolonged 'disease' course. Coexisting social conflict was common and may be a contributory factor. Careful explanation and reassurance to both the child and parents remains the mainstay of management.

The role of oxidative stress in the pathogenesis of age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blind registration in the developed world, and yet its pathogenesis remains poorly understood. Oxidative stress, which refers to cellular damage caused by reactive oxygen intermediates (ROI), has been implicated in many disease processes, especially age-related disorders. ROIs include free radicals, hydrogen peroxide, and singlet oxygen, and they are often the byproducts of oxygen metabolism. The retina is particularly susceptible to oxidative stress because of its high consumption of oxygen, its high proportion of polyunsaturated fatty acids, and its exposure to visible light. In vitro studies have consistently shown that photochemical retinal injury is attributable to oxidative stress and that the antioxidant vitamins A, C, and E protect against this type of injury. Furthermore, there is strong evidence suggesting that lipofuscin is derived, at least in part, from oxidatively damaged photoreceptor outer segments and that it is itself a photoreactive substance. However, the relationships between dietary and serum levels of the antioxidant vitamins and age-related macular disease are less clear, although a protective effect of high plasma concentrations of alpha-tocopherol has been convincingly demonstrated. Macular pigment is also believed to limit retinal oxidative damage by absorbing incoming blue light and/or quenching ROIs. Many putative risk-factors for AMD have been linked to a lack of macular pigment, including female gender, lens density, tobacco use, light iris color, and reduced visual sensitivity. Moreover, the Eye Disease Case-Control Study found that high plasma levels of lutein and zeaxanthin were associated with reduced risk of neovascular AMD. The concept that AMD can be attributed to cumulative oxidative stress is enticing, but remains unproven. With a view to reducing oxidative damage, the effect of nutritional antioxidant supplements on the onset and natural course of age-related macular disease is currently being evaluated.

Acute occlusion of the retinal arteries: current concepts and recent advances in diagnosis and management

PURPOSE/BACKGROUND

Central retinal artery occlusion (CRAO) is usually a blinding event, and is not an infrequent presentation to the accident and emergency (A&E) department. The evidence-base in support of current treatment options is weak.

METHODS

This paper reviewed the literature germane to the diagnostic, therapeutic and prognostic aspects of retinal arterial occlusive disease.

RESULTS

The visual prognosis associated with CRAO remains poor, and current therapeutic practices are of unproven benefit. The non-ophthalmologist in the A&E department should lie the patient flat and give a stat dose of intravenous acetazolamide in an attempt to improve the retinal perfusion pressure.

CONCLUSION

The management of acute occlusion of the central retinal artery has not changed over the past 30 years, although the potential benefits of superselective intra-arterial fibrinolytic therapy warrant evaluation in a randomised controlled trial. The identification of underlying pathology is an essential component of medical care, and all cases should be followed up by an ophthalmologist because of the possibility of ocular rubeosis.

Optic atrophy in association with cobalamin C (cblC) disease

PURPOSE

To report the association of optic atrophy with cobalamin C (cblC) disease.

METHODS

Descriptive case reports on three patients, two of whom were siblings.

RESULTS

All three patients with cblC disease exhibited bilateral optic atrophy with decreased visual acuity. Of the two siblings, the younger sister had received cobalamin supplements from birth and the mother had been given cobalamin supplements prenatally.

CONCLUSION

These three cases confirm the association of optic atrophy with cblC disease. Early treatment with cobalamin supplements does not appear to prevent the development of optic atrophy.

Local intra-arterial fibrinolysis for acute occlusion of the central retinal artery: a meta-analysis of the published data

BACKGROUND/AIM

Central retinal artery occlusion (CRAO) is typically associated with a poor visual outcome. Several favourable reports of local intra-arterial fibrinolysis (LIF), which involves the superselective administration of a thrombolytic agent directly into the ophthalmic artery, have appeared in the recent literature. The aim of this study was to critically appraise these studies in a collective fashion.

METHODS

A meta-analysis was performed of all the published literature germane to LIF in cases of CRAO.

RESULTS

Of the 16 studies identified, all were retrospective and non-randomised. After correction for data duplication, the results of LIF in 100 patients can be reported. A final acuity of 6/6 or better was seen in 14% of patients following LIF, and a visual result of 6/12 or better was seen in 27% of subjects. A poor final acuity of 3/60 or worse was seen in 60.6% of eyes treated with local intra-arterial fibrinolysis. These results compare favourably with conventional forms of therapy. Potentially serious complications were seen in four patients, but no patient suffered a permanent neurological deficit.

CONCLUSION

The results of this study suggest that there may be a marginal visual benefit associated with LIF compared with conventional management of CRAO. However, the methodology of the cited studies was often unsatisfactory, and a randomised controlled trial of LIF in cases of CRAO is justified. Outside of a randomised clinical trial, the use of superselective fibrinolytic therapy for CRAO cannot be recommended on the basis of current evidence.

The changing pattern of cytomegalovirus retinitis in human immunodeficiency virus disease

There have been profound changes in the pattern of cytomegalovirus (CMV) retinitis over the last two decades. The epidemiology and behaviour of CMV retinitis has been significantly altered by Acquired Immune Deficiency Syndrome (AIDS). It was uncommon prior to the AIDS epidemic, but soon became the most common retinal infection in AIDS patients. In the past several years, highly active anti-retroviral treatment (HAART) has achieved a dramatic improvement in the prognosis for patients infected with human immunodeficiency virus (HIV). As a result, HIV patients are living longer and have a reduced risk of CMV retinitis. Some patients with CMV retinitis who respond to HAART develop a transient symptomatic vitritis while others undergo no reactivation of their retinitis despite having no specific anti-CMV therapy. This pattern is likely to undergo further change as the treatment of HIV and CMV disease continues to improve.

The role of ophthalmic triage and the nurse practitioner in an eye-dedicated casualty department

PURPOSE

To evaluate the appropriateness of triage decisions in a busy ophthalmic casualty department and to assess the diagnostic and management skills of eye-dedicated nurse practitioners.

METHODS

Three hundred and one consecutive patients attending the Birmingham and Midland Eye Centre (BMEC) accident and emergency (A&E) department over a 2 week period were included in this prospective study. Patients were categorised in terms of urgency in concordance with strict guidelines, and the agreement between the final diagnosis and this system of prioritisation was then investigated. To evaluate nurse practitioner (NP) skills, all patients seen and managed by a NP were also assessed by the most senior doctor in casualty at the time in a masked fashion. Waiting times and a breakdown of waiting times were also calculated.

RESULTS

Upon establishment of a diagnosis, triage category allocation was found to be appropriate in all 301 cases. Fifty patients (16.67%) were seen by the NP. Of these the supervising doctor concurred with the NP diagnosis in all cases and with the proposed management in 96% of cases. The mean waiting time (+/- SD) was 83.43 +/- 45.84 min, with a range of 5-335 min. The delay before being attended to was greater for less urgent cases as categorised by the triage system.

CONCLUSION

This study confirms the high standard of diagnostic and management skills of the ophthalmic NP and indicates that the triage system of patient prioritisation is accurate. Waiting times in the A&E department remain unacceptable and ways of addressing this include improved ophthalmic training of general practitioners, diverting a greater proportion of non-acute cases to the primary care clinic and expanding the role of the NP.

Macular pigment optical density measurement: a novel compact instrument

A compact device to derive the optical density of human macular pigment (MP) using heterochromatic flicker photometry is described. The validity of the system is assessed by measuring the optical density spectra of MP in 12 healthy subjects and comparing this with well-established previously published values. The mean spectral absorbance characteristics of MP across subjects corresponds well with accepted values. As reported in other studies, our measurements show a wide variation of MP optical densities between individuals. In our technique within-subject variability is low; standard deviations are between 0.025 and 0.15 in most cases. The overall optical density of MP ranged from 0.08 to 0.84 with a mean of 0.496 and standard deviation of 0.257 at 460 nm. The stimulus size was 0.95 degrees. The unique feature of the technique is that it allows free viewing (not Maxwellian View) of the stimulus, it can be conducted easily and quickly and does not need frequent re-calibration.

Cytomegalovirus retinitis in patients with acquired immune deficiency syndrome

Cytomegalovirus (CMV) retinitis is the most common intra-ocular infection in patients with acquired immune deficiency syndrome (AIDS), and a leading cause of AIDS-related morbidity. Untreated CMV retinitis in AIDS patients is a progressive and potentially blinding disorder. The diagnosis of CMV retinitis is a clinical one and it is important for physicians to be familiar with the clinical features of the disease. Ophthalmic screening of AIDS sufferers should be undertaken at regular intervals, and this is dictated, in part, by the patient's CD4+ T-lymphocyte (CD4) counts. CMV retinitis may be treated with systemic ganciclovir, foscarnet or cidofovir, or with local (intravitreal) therpy. CMV-related retinal detachment is treated surgically. In some patients with quiescent CMV retinitis receiving highly active anti-retroviral therapy, anti-CMV maintenance therapy may be discontinued in favour of close ophthalmologic observation and CD4 count monitoring.

Non-organic visual loss

Visual complaints without a physical basis are not uncommon presentations to the general physician, the neurologist, or the ophthalmologist. These alleged visual disturbances may be psychogenic or feigned. The diagnosis is made when all possible contributory pathology of the visual system is excluded, and reassurance remains the cornerstone of management.

Acute intraoperative suprachoroidal haemorrhage in ocular surgery

PURPOSE/BACKGROUND

Acute intraoperative suprachoroidal haemorrhage (AISH) is the most sight-threatening complication of ocular surgery. We investigated the visual outcomes following this intraoperative event, patient characteristics that may predispose to it and the clinical features that may be of prognostic significance.

METHODS

The records of 45 cases of AISH collected from ophthalmic centres in the United Kingdom, Republic of Ireland and Switzerland were reviewed. Two satisfactory controls in terms of operative procedure, surgeon, age (+/- 5 years) and gender were found for each of 33 of our cases. Systemic and ocular characteristics were compared for cases and controls, and the visual results of all cases of AISH are analysed.

RESULTS

Cases and controls differed only in terms of axial length and pre-operative intraocular pressure, both of which were significantly greater for eyes that experienced an AISH (p < 0.05). Ten eyes (22.2%) achieved a final Snellen acuity of 6/12 or better. Statistically significant associations with a final acuity of counting fingers or worse included spontaneous nuclear expression (p = 0.02), retinal detachment (p < 0.0001), four-quadrant suprachoroidal haemorrhage (p = 0.007) and vision of perception of light or worse at the first dressing (p = 0.0001). Four of the 6 eyes that experienced an AISH during phacoemulsification surgery had a visual outcome of 6/12 or better, and this was significantly greater than for cases involving extracapsular cataract surgery (p = 0.004).

CONCLUSION

The results indicate that longer axial length and higher pre-operative intraocular pressure are associated with increased risk of AISH. Poor visual results are more likely following spontaneous nuclear expression, retinal detachment, four-quadrant suprachoroidal haemorrhage or vision of perception of light or worse at the first dressing. The results also suggest that AISH complicating a phacoemulsification procedure has a more favourable visual prognosis than AISH that occurs during extracapsular cataract surgery.

Surgical excision of subfoveal neovascular membranes

BACKGROUND

Subfoveal choroidal neovascular membranes (CNV) are a cause of significant visual impairment. Laser treatment of such lesions results in visual loss. Surgical excision of CNV may allow stabilisation or improvement of vision. A series of results of surgical excision are presented.

METHODS

The records for 43 eyes of 40 consecutive patients undergoing surgical excision of CNV not associated with age-related macular degeneration (AMD) were reviewed retrospectively. Statistical analyses of the relationship between pre-operative factors and post-operative visual results were made. Improvement or worsening of visual acuity was defined as a change of more than 2 lines of Snellen acuity.

RESULTS

In 79.1% of patients visual acuity was improved or unchanged following surgery, and in 20.9% there was a reduction of Snellen acuity. There was no statistically significant association between visual outcome and age, gender, duration of visual symptoms, cause of CNV, presence of subretinal haemorrhage, elevation of retina by subretinal fluid, prior laser surgery, or the presence of pre-operative or intraoperative subretinal haemorrhage. There was a possible association between the non-use of gas tamponade and an increased chance of reduced vision. Visual loss was more likely in those eyes with good pre-operative visual acuity. Recurrence of CNV was noted in 10 (23%) eyes; repeat surgery was not associated with a worse visual outcome.

CONCLUSIONS

Surgical excision of CNV not related to AMD is a promising technique. More meaningful assessment of visual function in these patients will allow refinement of case selection.

Correlation between the orbital and intraocular portions of the optic nerve in glaucomatous and ocular hypertensive eyes

BACKGROUND/PURPOSE

It has recently been reported that the retrobulbar optic nerve diameter (OND) and cross-sectional area (ONCSA) are reduced in glaucoma. This study was performed to investigate the correlation between the orbital and intraocular portions of the optic nerve.

METHODS

One eye of 20 volunteers (16 glaucoma subjects, 4 ocular hypertension subjects) underwent optic disc analysis using Heidelberg retinal tomography, and echographic measurements of the retrobulbar optic nerve.

RESULTS

The male-to-female ratio was 6.5:3.5, and the mean age of our sample (+/- SD) was 62.25 +/- 13.7 years. Orbital optic nerve diameter and cross-sectional area correlated significantly and positively with the neuroretinal rim area (Spearman's rank correlation coefficient; OND: rs = 0.488, p = 0.0336; ONCSA: rs = 0.619, p = 0.0079), but not with any other topographical disc data. The retrobulbar optic nerve cross-sectional area-to-disc area ratio (ONCSA/D) was found to have a significant negative correlation with the cup area/disc area ratio (simple regression analysis; r = -3.948, p = 0.046), and a statistically demonstrable positive correlation with the neuroretinal rim area/disc area ratio (r = 0.451, p = 0.046).

CONCLUSION

The results of this study indicate that orbital optic nerve dimensions are a reflection of the neuroretinal rim area of the optic disc. Echographic measurements of the retrobulbar nerve may be additive to the traditional triad of raised intraocular pressure, field defects and glaucomatous optic neuropathy that suggests a diagnosis of glaucoma.

Evaluation of optic disc cupping using high-resolution ocular ultrasound

BACKGROUND/PURPOSE

The new Biovision B-Scan Probe has greater resolution than its predecessors because of its posteriorly placed focus (25 mm inside the eye) and the consequent reduction in size of the sound field. We investigated the accuracy, reproducibility and test-retest variability of two-dimensional optic cup measurements using this new-generation B-scanner.

METHODS

One randomly selected eye of 20 patients underwent five repeated measurements of vertical (VOCD) and horizontal optic cup diameters (HOCD), and optic cup depth, using confocal scanning laser tomography (Heidelberg Retinal Tomograph) and high-resolution ultrasound (Biovision, Chiron Vision, UK) on two separate occasions. There was one operator per instrument who was masked to all clinical data and previous measurements. Accuracy of ultrasound readings was quantified by comparing the results with those of Heidelberg Retinal Tomography (HRT).

RESULTS

The 95% confidence interval for the bias of echographic vertical and horizontal cup diameter measurements was -95 +/- 48 microns and -19 +/- 72 microns respectively, and -87 +/- 328 microns for cup depth readings. The indices of reproducibility (mean coefficient of repeatability +/- SD) were: VOCD: 177 +/- 105 microns [B-scan] 209 +/- 100 microns [HRT]; HOCD: 179 +/- 61 microns [B-scan], 205 +/- 101 microns [HRT]; cup depth: 206 +/- 63 microns [B-scan], 204 +/- 124 microns [HRT]. Ninety-five per cent limits of agreements between initial and retest values for ultrasound were 18 +/- 136 microns [VOCD], 2 +/- 144 microns [HOCD] and 4 +/- 156 microns [cup depth], compared with 1 +/- 104 microns [VOCD], 20 +/- 102 microns [HOCD] and 3 +/- 168 microns [cup depth] for scanning laser tomography.

CONCLUSION

The results demonstrate that measurements of optic cup diameter and depth using ultrasound correlate strongly with corresponding HRT readings. These echographic measurements are reproducible, and not subject to clinically meaningful test-retest variability. This technique of measuring two-dimensional cup parameters does not require expensive specialist equipment and has many potential clinical applications which are discussed.

Necrotizing sclerokeratitis following uncomplicated cataract surgery

PURPOSE

To report a case of surgically induced necrotising sclerokeratitis (SINS) with imminent uveal prolapse following uncomplicated cataract surgery.

METHODS

Case report.

RESULTS

The causative agent was found to be a subtarsal abscess and the condition responded to drainage of the localised infection and a course of topical antibiotics.

CONCLUSION

This report represents the first account of postoperative scleral necrosis arising from a subconjunctival abscess, and illustrates the importance of identifying all aetiopathogenic factors in cases of postsurgical necrotizing scleritis.

Trabeculectomy augmented with mitomycin C application under the scleral flap

AIM

The authors investigated the safety and intraocular pressure (IOP) lowering effectiveness of trabeculectomy augmented with mitomycin C application beneath the scleral flap, and assessed the influence of preoperative risk factors on the surgical outcome.

METHODS

A retrospective study of 72 consecutive high risk eyes undergoing trabeculectomy with adjunctive mitomycin C (0.2 mg/ml) applied under the scleral flap for 5 minutes was performed. Each eye was ascribed a score based on the number of preoperative risk factors, and categorised into one of three risk factor groups. Success was described as unqualified where IOP was < or = 21 mm Hg without medication and qualified where antiglaucomatous therapy was required to maintain it at such a level. A life table analysis of IOP control was calculated.

RESULTS

The mean IOP (SD) fell from a preoperative level of 28.4 (6.9) to a level of 16.63 (8.06) mm Hg at the last follow up (paired Student's t test: p < 0.0001). Fifty two eyes (72%) were classed as unqualified successes. The survival rates did not differ significantly between different risk factor groups (log rank test: chi 2 = 0.967, p > 0.1). The incidence of postoperative complications compared favourably with reports of mitomycin C application between Tenon's capsule and the undissected scleral bed.

CONCLUSION

The results illustrate that mitomycin C applied beneath the scleral flap during trabeculectomy in high risk eyes is associated with a success rate comparable to other modes of application. The incidence of potentially serious complications such as conjunctival wound leak and prolonged hypotony was lower than previously published data reporting sub-Tenon's administration of mitomycin C. The number and nature of preoperative risk factors do not appear to influence the surgical outcome. A possible mechanism of action is proposed.

Echographic measurements of the retrobulbar optic nerve in normal and glaucomatous eyes

AIM

A study was designed to investigate whether measurements of the optic nerve diameter (OND) and cross sectional area (ONCSA), as measured by B-scan ultrasonography, are altered in glaucoma. The reproducibility and test-retest variability of echographic estimates of retrobulbar optic nerve dimensions was also tested.

METHODS

One eye of 49 glaucoma patients and 90 control subjects underwent five repeated echographic measurements of the maximal interpial diameter and cross sectional area of the orbital optic nerve on two separate occasions. All measurements were taken by one experienced ultrasonographer.

RESULTS

Mean optic nerve diameter (SD) for the control group was 2.86 (0.46) mm, and was independent of height (multiple regression analysis: p = 0.21), axial length (p = 0.74), spherical equivalent (p = 0.97), sex (ANOVA: p = 0.36), or race (p = 0.14), but was inversely related to age (p = 0.01). Reproducibility of OND readings in control subjects was 0.149 mm (coefficient of repeatability). Test-retest variability of interpial diameter was -0.02 (0.29) mm. Mean interpial diameter of the optic nerve was significantly smaller among glaucomatous eyes (2.58 (0.501) mm) than controls (Mann-Whitney U test: p < 0.0001). Glaucomatous optic nerves also had a significantly smaller cross sectional area (6.68 (2.58) mm2) than those of healthy volunteers (8.25 (1.67) mm2) (p = 0.004).

CONCLUSION

Echographic measurements of the orbital optic nerve are highly reproducible and not subject to clinically meaningful test-retest variability. Optic nerve interpial diameter and cross sectional area are reduced in glaucomatous eyes, reflecting nerve fibre loss. This technique may be useful in distinguishing between normal and glaucomatous eyes where optic disc morphometry is inconclusive or impossible as a result of opaque media.

Bilateral macular holes resulting from septic embolization

PURPOSE

To report a previously undescribed cause of bilateral macular hole formation.

METHOD

Case report.

RESULTS

Septic emboli were noted at the center of the macula in both eyes of a 32-year-old man with acute bacterial endocarditis. Bilateral full-thickness macular holes later developed at the site of these retinal lesions.

CONCLUSION

This case represents the first report of fundus lesions in septicemia resulting in full-thickness macular hole formation.

Effect of applanation tonometry on mean corneal curvature

PURPOSE

To evaluate whether applanation tonometry affects corneal curvature and if so, the implications for intraocular lens power calculation.

SETTING

Birmingham and Midland Eye Hospital, Birmingham, England.

METHODS

Twenty-two patients attending the preoperative assessment clinic were enrolled in the study. Keratometry was performed immediately before, 1 minute after, and 10 minutes after standard Goldmann tonometry. Main outcome measures were mean corneal refractive power and its reproducibility (coefficient of repeatability).

RESULTS

No clinically significant difference was noted between preapplanation and postapplanation readings (P = .6), and reproducibility was not significantly affected.

CONCLUSION

The results indicate that corneal applanation before keratometry does not compromise the prediction of postoperative refraction.

Phacoemulsification versus endocapsular cataract extraction in a unique cohort of patients

The visual recovery and refractive results of 33 consecutive patients (66 eyes) undergoing standard endocapsular cataract extraction in one eye and simultaneous phacoemulsification in the fellow eye are reported. One surgeon performed all the operations. Surgically induced astigmatism was evaluated for the two techniques in terms of: (1) the proportion of eyes with a refractive cylinder of 1.5 dioptres (D) or less; (2) the interocular difference in post-operative astigmatism. Eyes undergoing phacoemulsification had a significantly lower mean induced cylinder (paired Student's t-test: t = 3.729; p < 0.001) and were more likely to exhibit a cylinder of 1.5 D or less (chi-squared test with Yates' correction: chi 2 = 7.88; p < 0.01) than the nuclear expression group. For paired eyes less post-operative astigmatism (Wilcoxon's signed rank test: T = 92; p < 0.01) was seen in the phacoemulsification eye. At the time of the last post-operative assessment a significantly higher proportion of phacoemulsified eyes achieved a corrected Snellen visual acuity of 6/6 or better than their fellow eyes (McNemar's test: p < 0.01). The results of this unique cohort of patients confirm the beneficial effects of phacoemulsification on astigmatism and visual outcome in the early post-operative period.

Day-case trabeculectomies: safety and efficacy

A comparison of 90 day-case and 102 in-patient trabeculectomies is presented. There was no statistically significant difference in the incidence of post-operative hyphaema (Chi-squared test p = 0.84), shallow anterior chamber (p = 0.46), flat bleb (p = 0.84) or hypotony (p = 0.87) between the two groups. Casualty attendances, readmissions and further surgery in the postoperative period were seen with similar frequency in each group. Intraocular pressure control three months following surgery was not compromised by undergoing the procedure as a day-case (p = 0.29). This study demonstrates the safety and efficacy of ambulatory filtration surgery.

Simultaneous bilateral cataract extraction in the UK

AIMS/BACKGROUND

Simultaneous bilateral extracapsular cataract extraction (SBCE) is not routinely performed in the developed world. This study investigated the safety and efficacy of this procedure as performed in the UK.

METHODS

A review of 319 consecutive patients (638 eyes) who underwent SBCE with posterior chamber intraocular lens implantation is presented.

RESULTS

The incidence of intraoperative complications was 7.7%. These included posterior capsule rupture (0.8%) and vitreous loss (0.3%). Postoperative complications were seen in 8.7% of operated eyes and included iris prolapse (0.3%) and raised intraocular pressure (3.0%). Endophthalmitis occurred in one eye (0.15%). There were no major bilateral complications, and, in particular, no cases of bilateral endophthalmitis. Final visual acuities compared favourably with reports for unilateral surgery. Eighty two per cent achieved a final visual acuity of 6/12 or better, and 41% tested 6/6 or better.

CONCLUSION

This study illustrates that SBCE is not associated with an increased incidence of complications and that the visual results are good. Where indicated, and under strict surgical protocol, this procedure is safe.

Affective reactions to failure as a function of effort and depression

University students, divided on a quartile split into low (n = 53) and high (n = 42) depression groups (Beck scores of 0-1 or 7 and higher), were presented a series of failure situations in which failure occurred under high effort (with situational factors causing failure) or low effort. Subjects rated their affective reactions to each situation. It was hypothesized that the group low on depression would feel worse after high effort (since this would challenge their sense of self-efficacy) whereas the high depression group would feel better in this condition (since attribution of failure to situational factors would protect their sense of self-esteem). Results were consistent with expectations for the group low on depression. For the group high on depression, the means were rank-ordered as predicted but the difference was not significant.

The obstetric and gynaecological implications of pseudoxanthoma elasticum

The obstetric aspects of 54 pregnancies in 20 women with pseudoxanthoma elasticum (PXE) have been reviewed. Forty live births were delivered vaginally, three of them were preterm. Twelve pregnancies miscarried at between 6 and 14 weeks gestation and two were terminated in the 8th week for psychiatric reasons. Fetal losses in two instances were attributed to cervical incompetence. One baby died at 4 days of age from a complex congenital cardiac anomaly. No abnormal maternal genital or gastrointestinal bleeding was recorded. Hypertension complicated seven pregnancies. Abdominal striae developed in all patients, the severity of which correlated with weight gain and the number of pregnancies. All the women had normal gynaecological histories, none had excessive menstrual bleeding or increased episodes of menorrhagia. The eye, blood vessels and other organ systems involved in PXE were unaffected by pregnancy. Apart from the increased risk of first trimester miscarriage and the cosmetic deterioration of the abdominal skin, there are few serious complications in pregnancy in patients with PXE.

Protein phosphorylation in a tetradecanoyl phorbol acetate-nonproliferative variant of 3T3 cells

The 3T3-TNR9 cell line is a variant of Swiss 3T3 cells which does not respond mitogenically to tumor promoters, but does respond mitogenically to epidermal growth factor, fibroblast growth factor, and serum. To elucidate differences between tumor promoters and polypeptide mitogens in the pathway(s) of mitogenesis which might be responsible for the nonresponsiveness of the 3T3-TNR9 cells, we have examined in these cells the early protein phosphorylation events known to be associated with mitogenesis in the parental 3T3 cells. We find that the 3T3-TNR9 cells display levels of tetradecanoyl phorbol acetate binding and of a calcium- and phospholipid-dependent protein kinase activity which are at least the equal of those seen in the parental 3T3 cells, implicating some postreceptor event in the nonmitogenic phenotype. In addition, we find that phosphorylation of the epidermal growth factor receptor and of 80-kDa and 22-kDa proteins, as well as the tyrosine phosphorylation of a 42-kDa protein, all proceed normally in the nonmitogenic variant, even though these phosphorylations must depend on the activation of different kinases. Thus, all these early phosphorylation reactions are intact in the 3T3-TNR9 cells. Although these phosphorylations may be necessary, they clearly are insufficient to trigger mitogenesis.