Retinal thickness variation in the diabetic patient measured by the retinal thickness analyser

AIM—To evaluate the potential of the retinal thickness analyser (RTA) as an objective tool for assessment and follow up of diabetic macular oedema.
METHODS—A prototype of the RTA that operates on the principle of laser slit biomicroscopy was used. Retinal thickness was obtained in 41 eyes of 41 diabetic patients. The clinical diagnosis was cystoid macular oedema (CMO) in 10 eyes, clinically significant macular oedema (CSMO) without retinal cysts in 21 eyes, and "dry" macula following grid pattern laser treatment in 10 eyes. The control group consisted of 46 eyes of age matched healthy volunteers.
RESULTS—In normal eyes (46 eyes), the foveal thickness measured was 178 (SD 44) µm and the macular thickness around the fovea was 311 (51) µm. The eyes with CMO displayed the largest foveal thickening, 875 (287) µm (390% increase compared with normal values). The average thickness of the fovea in the non-cystoid CSMO group was 427 (175) µm (144% increase compared with normal fovea). The average thickness of the foveal centre in eyes judged as having "dry" macula after laser treatment was 315 (71) µm (77% increase compared with normal value and a 26% decrease in thickness compared with the CSMO eyes). Statistically significant differences were found in central thickness between these four groups (p = 0.0001). The average thickness at 500 µm surrounding the fovea was 566 (202) µm in the CSMO eyes compared with 311 (51) µm in normal eyes (80% increase). The "dry" macula group (after undergoing laser treatments) had an average thickness of 414 (94) µm (27% decrease compared with CSMO eyes and a 33% increase compared with eyes of healthy controls).
CONCLUSIONS—RTA is a system for quantifying macular thickness and imaging of macular pathology. The system can be a useful tool for diagnosis of macular diseases and for evaluation of the effect of treatment modalities.

Keywords: diabetic retinopathy; retinal thickness; macular oedema; retinal imaging     

Retinal vessel dilatation and elongation precedes diabetic macular oedema

AIMS/BACKGROUND—Retinal vessel dilatation is a well known phenomenon in diabetes. In this study, the theory of whether excessive changes in diameter and length of retinal vessels occur in the development of diabetic macular oedema was tested, supporting a hypothesis that the development of diabetic macular oedema may be linked to hydrostatic pressure changes described in Starling's law.
METHODS—From fundus photographs of diabetic patients attending a regular eye screening programme, the diameter and segment length of retinal vessels were measured in three retinopathy groups (12 patients each) with diabetic macular oedema (DMO), background retinopathy and no retinopathy, over a period of approximately 4 years, ending at the time of diagnosis of diabetic macular oedema in the DMO group.
RESULTS—A statistically significant dilatation and elongation of retinal arterioles, venules, and their macular branches was found before the diagnosis of macular oedema in the DMO group. No significant changes were found in the other two groups.
CONCLUSION—It is suggested that Starling's law applies to the formation of oedema in the retina as in other tissues.

     

Scanning laser tomography Z profile signal width as an objective index of macular retinal thickening

AIMS—(i) To evaluate the relation between retinal thickness and the Z profile signal width of a scanning laser tomographer in selected patients exhibiting clinically manifest and circumscribed macular retinal thickening; (ii) to compare the Z profile signal width values of a group of age similar normal subjects with those of the patients with macular retinal thickening; and (iii) to present the methodology underlying the Z profile signal width derivation.
METHODS—Three patients with the following conditions were selected: widespread diabetic macular oedema; localised diabetic macular oedema; and macular hole. The patients were selected because they exhibited clinically manifest and circumscribed macular retinal thickening. Patients underwent fundus photography and a clinical examination which included fundus biomicroscopy. Fourteen age similar normal subjects were also assessed. The Heidelberg retina tomograph (HRT) was utilised to acquire seven topographic images of each macula. Z profile signal width data were analysed using custom software. Signal width was measured at 50% of the maximum intensity.
RESULTS—For each patient with macular retinal thickening, Z profile signal width analysis (after normalisation to reduce the influence of variation in reflectance intensity between successive images) revealed a significant (p<0.0001) localised increase of signal width which agreed with the HRT topographic analysis of retinal height, and also the clinical assessment of retinal thickness. The mean normalised Z profile signal width for the normal subjects (assessed over the whole image) ranged from 0.278 (SD 0.039) to 0.444 (0.063); these values compared with those obtained from patients in areas of macular retinal thickening of 0.761 (0.224) to 0.953 (0.194). Z profile signal width test-retest data for the patient with localised diabetic macular oedema were plus or minus 0.159 which compared with a mean signal width value of 0.761.
CONCLUSION—The evidence of this study, based upon three selected patients with macular retinal thickening and 14 normal subjects, would suggest that Z profile signal width analysis offers a non-invasive, objective, topographic, and reproducible index of macular retinal thickening. Studies employing larger sample sizes are required to determine the true clinical worth of the technique.

Keywords: diabetic macular oedema; retinal thickening; scanning laser tomography; Z profile     

A new colour vision arrangement test to detect functional changes in diabetic macular oedema

AIM—A study was undertaken to investigate the correlation between colour discrimination tests and the presence of macular oedema in patients with type I diabetes to find a sensitive diagnostic tool for the detection of early functional changes.
METHODS—The study was performed in 39 type I diabetic patients, 10 with and 29 without macular oedema. The examination included biomicroscopy, fundus photography of the macula, videofluorescein angiography, the LogMAR visual acuity chart, Farnsworth-Lanthony desaturated D-15 test, and the new Mollon-Reffin "Minimalist" test for colour vision deficiencies version 6.0.
RESULTS—A highly significant correlation was found between the tritan value of the Mollon test and the presence of clinically significant macular oedema (p<0.0015), with a high sensitivity (88.9%) and specificity (93.3%). The DD-15 test was not significant (p=0.345) and showed low sensitivity for the presence of macular oedema (36%). All variables concerning the grading of macular oedema showed a highly significant association with the tritan values of the Mollon test (p<0.0001).
CONCLUSION—The results suggest that the Mollon-Reffin "Minimalist" test version 6.0 is the best colour discrimination test for detecting macular oedema, with higher specificity and sensitivity than the other methods used in the study.

     

Reproducibility of volumetric measurements of normal maculae with the Heidelberg retina tomograph

AIMS—The Heidelberg retina tomograph (HRT) is a scanning laser ophthalmoscope with confocal optics. The reproducibility of the optic nerve head topography is accurate and reliable. The authors describe a new technique for the assessment of macular thickening by volumetric quantification and present the results of its reproducibility in normal subjects.
METHODS—Topographic images of the macula, centred on the fovea were obtained in one eye of 44 normal subjects. The volumes above the reference plane bound by a 1 mm, 2 mm, and 3 mm diameter circle were measured. The reference plane was adjusted to the lowest point of the height variation of the contour line at each examination. The reproducibility of repeated measurements within a 2 mm diameter circle was assessed in 20 eyes selected at random. Three HRT scans of each eye were obtained. The measurements of volume above reference plane of each scan were repeated three times on three separate days.
RESULTS—The intrascan coefficients of variability measured 7.12-9.57%. The 95% confidence interval for the geometric mean ratio of single volume measurements was 0.92 to 1.24 for scans 1 and 2, 0.89 to 1.17 for scans 1 and 3, and 0.81 to 1.12 for scans 2 and 3. When the mean of three measurements of one scan were compared with the mean of three measurements of a second scan, the 95% confidence interval for their geometric mean ratio was 0.89 to 1.20 for scans 1 and 2, 0.89 to 1.16 for scans 1 and 3, and 0.84 to 1.13 for scans 2 and 3. The average standard deviation (SD) for one measurement per scan was 0.02 mm³, and 0.019 mm³ for two or three measurements per scan. Linear regression demonstrated a significant increase in SD as volumetric measurements increased (p = 0.003). Age did not significantly affect the SD of volumetric measurements (p = 0.797). The authors found no significant differences in volumetric measurements across all ages for all three circles (p = 0.314, p = 0.471, p = 0.267).
CONCLUSION—Good reproducibility for volumetric measurements at the macula was found with the HRT using the above technique in normal subjects. This method may be extremely useful for the identification and quantification of diabetic macular oedema and for monitoring the effects of argon laser photocoagulation.

Keywords: Heidelberg retina tomograph; volume above reference plane; reproducibility; macula     

Differentiating full thickness macular holes from impending macular holes and macular pseudoholes

AIMS—The reliability of scanning laser ophthalmoscope (SLO) microperimetry in differentiating full thickness macular holes from macular pseudoholes and impending macular holes was evaluated.
METHODS—106 eyes with the clinical diagnosis of full thickness macular holes, macular pseudoholes, and impending (stage 1) macular holes were examined for the presence of deep or relative scotoma using SLO microperimetry. The relation between these scotomas and the clinical diagnosis was studied.
RESULTS—Deep and relative scotomas were detected in all 57 eyes with clinically defined full thickness macular holes. In contrast, among 49 eyes diagnosed with macular pseudoholes or impending macular holes, no deep and only one relative scotoma was observed. The sensitivity of the presence of a deep scotoma as an indicator of the clinical diagnosis of a full thickness macular hole was 100% (57 of 57), and the specificity was 100% (49 of 49). The sensitivity of the presence of a relative scotoma was 100% (57 of 57) and the specificity was 98.0% (48 of 49).
CONCLUSION—With SLO microperimetry, full thickness macular holes can be precisely and objectively distinguished from other conditions that mimic macular holes.

     

Grid laser photocoagulation for macular oedema in uveitis or the Irvine-Gass syndrome

AIMS—To determine the effect of modified macular grid photocoagulation in patients with refractory macular oedema due to uveitis or cataract extraction.
METHODS—In this study 20 patients with macular oedema underwent modified macular grid laser photocoagulation and were followed by means of standardised examinations (day 0, months 2, 6, and 12) consisting of best corrected visual acuity and fluorescein angiography.
RESULTS—The mean visual acuity increased from 0.16 before to 0.3 after laser treatment (p=0.013), and fluorescein leakage was significantly reduced (p=0.005). Visual prognosis was influenced by duration of the uveitis, not by sex or age.
CONCLUSION—Modified macular grid laser photocoagulation had a beneficial effect on macular oedema caused by uveitis or the Irvine-Gass syndrome. A prospective, randomised study is needed to determine the exact place of modified macular grid photocoagulation in the treatment of patients with inflammatory or postsurgical macular oedema.

Keywords: macular grid photocoagulation; Irvine-Gass syndrome; macular oedema     

Diabetic retinopathy in people aged 70 years or older. The Oulu Eye Study

AIMS—To evaluate the presence and severity of diabetic retinopathy and the value of retinopathy screening in people aged 70 years or older.
METHODS—In a population based study on 500 of 560 eligible (89%) people aged 70 years or older, signs of diabetic retinopathy were evaluated through dilated pupils by an ophthalmologist using photographic and/or ophthalmoscopic methods.
RESULTS—23% of the study population (113/500) had diabetes mellitus. Signs of diabetic retinopathy were found in 24 people (21% of the diabetic population). Retinopathy changes were graded as mild to moderate non-proliferative retinopathy (NPDR) in 40 eyes (18 people), severe NPDR (preproliferative) in five eyes (four people), and proliferative in three eyes (two people). Preproliferative or proliferative changes were present in four people (3.5% of the diabetic population) and diabetic maculopathy was diagnosed in nine (8% of the diabetic population). Laser treatment was considered to be indicated in seven people for maculopathy, and in two for proliferative changes. In four people the visual acuity was reduced to a low vision level as a result of diabetic retinopathy.
CONCLUSION—In spite of the high prevalence of diabetes mellitus in the elderly population, the prevalence of vision threatening diabetic retinopathy, particularly proliferative retinopathy, is low. Ophthalmoscopically, reliable information on fundus changes could be obtained in 94%, but photographs were gradable in only 76% of the diabetic population. Therefore, the value of photographic screening for diabetic retinopathy in this age group is poor in comparison with younger age groups.

     

Evidence that upregulation of serum IGF-1 concentration can trigger acceleration of diabetic retinopathy

BACKGROUND—Acute reduction of chronic hyperglycaemia can accelerate early diabetic retinopathy. In adolescent patients with Mauriac's syndrome, this phenomenon is related to an upregulation of subnormal serum IGF-1 levels.
AIM—To obtain longitudinal data on serum IGF-1 and retinopathy status in poorly controlled adult insulin dependent (type 1) diabetic patients without Mauriac's syndrome, in whom hyperglycaemia is reduced by intensive insulin therapy.
METHODS—Four patients with chronic severe insulin deficiency and early microangiopathy were studied prospectively. Changes in plasma glucose, HbA_1c, serum IGF-1 levels, proteinuria, retinopathy, and clinical status were followed up closely.
RESULTS—Reducing hyperglycaemia from >16 mmol/l (equivalent to HbA_1c >11%) to <10 mmol/l (HbA_1c <8%) within 5 months increased serum IGF-1 levels by 70-220%. While proteinuria and symptomatic neuropathy regressed, retinopathy progressed from the mild to the severe non-proliferative stage with maculopathy (n=4), and to the proliferative stage (n=1). Laser coagulation was commenced upon the appearance of sight threatening macular oedema (n=4).
CONCLUSION—Upregulation of serum IGF-1 preceding retinal deterioration in these patients suggests a cause-effect relation, consistent with earlier experimental and clinical data.

Keywords: diabetes mellitus; macular oedema; metabolic control; intensive therapy; glycated haemoglobin A_1c; growth factors     

Bilateral involvement by age related maculopathy lesions in a population

AIMS—To describe the influences of age and sex on the frequency of bilateral age related macular degeneration (AMD) and age related maculopathy (ARM) lesions.
METHODS—The Blue Mountains Eye Study examined 3654 older Australians, 82% of permanent residents living in an area west of Sydney. Stereo macular photographs were graded for AMD (neovascular maculopathy and geographic atrophy) and early ARM lesions (soft drusen, reticular drusen, hyperpigmentation, and hypopigmentation).
RESULTS—Among 230 gradable cases of AMD or early ARM, 183 (80%) were bilateral. For AMD, 39/69 cases (57%) were bilateral, while for early ARM, 123/161 cases (77%) had signs in both eyes. Of the individual lesions, reticular drusen (91%) and indistinct soft drusen (79%) were most frequently present in both eyes. Geographic atrophy was bilateral in 56%, neovascular AMD in 40%, and distinct soft drusen in 47%, while hyperpigmentation was bilateral in 38% and hypopigmentation in only 28% of cases. A consistent age related increase in bilateral distribution was observed for most lesions. After adjusting for effects of age, current smoking, and AMD family history AMD and ARM component lesions, except for soft drusen, were more frequently bilateral in women. This sex difference was significant only for neovascular AMD, odds ratio 7.7 (95% confidence intervals 1.3-46.7). An AMD family history was more frequently reported in cases with bilateral involvement.
CONCLUSIONS—This study has documented differences in the age related bilaterality of individual ARM components with higher bilateral rates for reticular or indistinct soft drusen compared with other lesions. The increased bilaterality of most ARM lesions among women is likely to contribute to the increased age adjusted risk of AMD blindness found in women.

Keywords: age related maculopathy; age related macular degeneration; drusen     

Surgical management of macular holes: results using gas tamponade alone, or in combination with autologous platelet concentrate, or transforming growth factor β2

BACKGROUND—Vitrectomy and gas tamponade has become a recognised technique for the treatment of macular holes. In an attempt to improve the anatomic and visual success of the procedure, various adjunctive therapies—cytokines, serum, and platelets—have been employed. A consecutive series of 85 eyes which underwent macular hole surgery using gas tamponade alone, or gas tamponade with either the cytokine transforming growth factor β2 (TGF-β2) or autologous platelet concentrate is reported.
METHODS—Twenty eyes had vitrectomy and 20% SF₆ gas tamponade; 15 had vitrectomy, 20% SF₆ gas, and TGF-β2; 50 had vitrectomy, 16% C₃F₈ gas tamponade, and 0.1 ml of autologous platelet concentrate prepared during the procedure.
RESULTS—Anatomic success occurred in 86% of eyes, with 96% of the platelet treated group achieving closure of the macular hole. Visual acuity improved by two lines or more in 65% of the SF₆ only group, 33% of those treated with TGF-β2, and in 74% of the platelet treated group. In the platelet treated group 40% achieved 6/12 or better and 62% achieved 6/18 or better. The best visual results were obtained in stage 2 holes.
CONCLUSION—Vitrectomy for macular holes is often of benefit and patients may recover good visual acuity, especially early in the disease process. The procedure has a number of serious complications, and the postoperative posturing requirement is difficult. Patients need to be informed of such concerns before surgery.

     

Fundus autofluorescence in patients with macular holes imaged with a laser scanning ophthalmoscope

AIM—To demonstrate the usefulness of a recently developed technique of imaging fundus autofluorescence and to compare it with the results of fluorescein angiography in the diagnosis and staging of macular holes.
METHODS—The intensity and distribution of fundus autofluorescence was studied in 51 patients with idiopathic macular holes and pseudoholes using a confocal laser scanning ophthalmoscope (cLSO) and the images were compared with those obtained by fundus fluorescein angiography.
RESULTS—Autofluorescence imaging demonstrated bright fluorescence of macular holes with appearance similar to that obtained by fluorescein angiography. In contrast macular pseuodoholes showed no such autofluorescence. The attached operculum in stage 2 macular holes and the preretinal operculum in stage 3 macular holes showed focal decreased autofluorescence. The associated retinal elevation and the cuff of subretinal fluid were less fluorescent compared with the background autofluorescence of the normal fellow eyes. Following successful surgical treatment the autofluorescence of the macular holes was no longer visible.
CONCLUSION—Autofluorescence imaging with the cLSO makes the assessment of macular holes possible with an accuracy comparable with that of fluorescein angiography. Being non-invasive and rapid, autofluorescence imaging may become a useful alternative to fluorescein angiography in the assessment and the differential diagnosis of full thickness macular holes.

Keywords: fundus autofluorescence; macular hole; lipofuscin; retinal pigment epithelium; laser scanning ophthalmoscope     

Predicting visual outcome after macular hole surgery using scanning laser ophthalmoscope microperimetry

AIMS—To determine if postoperative visual outcome after successful macular hole surgery can be predicted with preoperative scanning laser ophthalmoscope (SLO) microperimetry.
METHODS—A prospective non-comparative study of 16 eyes in 15 patients examined before the surgery.
RESULTS—Visual outcome following macular hole surgery correlated with the "maximum parahole sensitivity", the highest intensity of stimulus to which the patient did not respond to any of the stimuli around the hole. Preoperative visual acuity, duration of the symptoms, size of the macular hole, and the "minimum parahole sensitivity", the lowest intensity to which the patient responded to all the stimuli around the hole, did not correlate significantly with postoperative visual acuity.
CONCLUSION—Preoperative assessment of patients using SLO microperimetry is a good predictor of visual outcome after macular hole surgery.

     

Late reopening of successfully treated macular holes

BACKGROUND—Most idiopathic macular holes can be closed by a surgical procedure combining vitrectomy, posterior hyaloid ablation, and fluid-gas exchange followed by postoperative positioning. Reopening of closed macular holes has been reported, but its frequency is not known. Here the incidence of reopening after successful macular hole surgery is reported.
METHODS—77 consecutive cases of idiopathic macular holes operated with autologous platelet injection between July 1993 and October 1995 were reviewed. The procedure consisted of three port vitrectomy, posterior hyaloid removal, non-expansile fluid-gas exchange, and autologous platelet injection followed by face down positioning. The incidence of reopening was analysed in the cohort of the 72 anatomical successes.
RESULTS—Mean follow up was 12.3 months. The macular hole reopened in five eyes of five patients (five out of 72 patients, 6.9%), in four cases after cataract extraction. In four cases too, an epiretinal membrane was noted, either clinically or during reoperation, and fluorescein leakage in the macular area was present in two cases. Three of the five cases of reopening were reoperated and all three were anatomical successes.
CONCLUSION—Late macular hole reopening occurred in five out of 72 patient, and in four cases after cataract surgery. The presence of an epiretinal membrane around the hole in four of them suggested that tractional forces were responsible for the reopening. Reoperation, performed in three cases, again closed the macular holes.

     

Smoking and neovascular form of age related macular degeneration in late middle aged males: findings from a case-control study in Japan

AIMS—The risk of smoking habits for developing the neovascular form of age related macular degeneration (neovascular form of AMD) were studied by a case-control study in Japan.
METHODS—56 male patients with the neovascular form of AMD and 82 healthy male controls, aged 50 to 69 years, were enrolled. A self administered questionnaire provided necessary information for the study subjects. Questions on smoking included whether the study subjects have ever smoked or not, and if smoked, depth of smoke inhalation, use of extra filter, age at starting smoking, average number of cigarettes smoked per day, and duration of smoking. When a smoker had stopped smoking, age at cessation was also recorded. Unconditional logistic analysis was adapted to calculate age adjusted odds ratios and their 95% confidence intervals (CIs) for smoking related factors.
RESULTS—Age adjusted odds ratio of developing the neovascular form of AMD was 2.97 (95% CI 1.00-8.84) for current smokers and 2.09 (0.71-6.13) for ex smokers, compared with non-smokers. All smoking habit/smoking history related variables such as use of extra filter, smoke inhalation level, age at starting smoking, duration of smoking, and Brinkman index were found to be significantly related to an increased risk of the neovascular form of AMD.
CONCLUSIONS—Suggested is the strong possibility that cigarette smoking enhances the neovascular form of AMD risk in late middle aged males, though the magnitude of risk by smoking variables might be overestimated, in part, because of health oriented controls.

     

Effects on IOP restoration and blood-aqueous barrier after long term treatment with latanoprost in open angle glaucoma and ocular hypertension

AIMS—To evaluate whether long term treatment with the prostaglandin analogue latanoprost has a deleterious effect on the blood-aqueous barrier (BAB) and to determine the duration of the effect on intraocular pressure (IOP) after withdrawal of treatment.
METHODS—Patients with ocular hypertension or glaucoma were topically treated with latanoprost 50 µg/ml once daily for 6-12 months. In 26 patients IOP was followed for 14 days after withdrawal of treatment. Aqueous flare was measured with a laser flare meter during 6-12 months' treatment in 16 patients.
RESULTS—On the last day of treatment IOP was 6.9 mm Hg (95% CI 5.3-8.5) lower than before treatment. It increased slowly during the follow up period but was still 1.3 mm Hg (95% CI 0.2-2.5) lower than pretreatment IOP 14 days after cessation of treatment. No change in aqueous flare was seen throughout the study.
CONCLUSION—Latanoprost has no clinically significant effect on the permeability of the BAB and IOP will return to pretreatment levels within a few weeks, indicating that latanoprost is safe for long term treatment.

     

Relation between pressure determined by ophthalmodynamometry and aortic pressure in the dog

AIMS—Ophthalmodynamometry has been used extensively since the last century; however, controversy surrounds what it actually measures. This study was set up to determine the relation between ophthalmodynamometric (ODP) and systemic blood pressures.
METHODS—Aortic pressure was continuously monitored and altered by phlebotomy in six anaesthetised dogs, while ophthalmodynamometry was performed, by directly altering intraocular pressure. Maxillary artery pressure was monitored in two animals. All pressure transducers were zeroed at eye level.
RESULTS—Mean ODP was 96.6% (1.6%) (95% confidence interval, n = 49) of aortic pressure. Mean maxillary artery pressure was 95.7% (5.5%) (95% CI, n = 16) of aortic pressure. ODP was 1.9 (0.6) mm Hg (95% CI, n = 33) higher than maxillary artery pressures.
CONCLUSION—ODP was only slightly below aortic pressure and not significantly different from maxillary artery pressure, the analogue of the internal carotid artery in humans. These results also suggest a retinal artery collapse pressure of at least 1.9 mm Hg.

Keywords: ophthalmodynamometry; dog; arterial pressure     

Pseudoexfoliation syndrome and secondary cataract

AIM/BACKGROUND—The pseudoexfoliation (PEX) syndrome is frequently associated with impairment of the blood-aqueous barrier. This study analysed if this might stimulate secondary cataract following cataract extraction.
METHODS—This historical cohort study included 197 eyes of 197 patients (99 with and 98 without PEX) that underwent extracapsular cataract extraction with posterior chamber lens implantation (PMMA optic) between 1985 and 1991. Secondary cataract was defined as opacification of the axial posterior capsule and decrease of visual acuity by two or more lines. Mean follow up was 23.8 months. For statistical analysis, the Kaplan-Meier method and multivariate Cox regression analysis were used.
RESULTS—Secondary cataract was observed within 24 months in 35% (SD 7%) of all eyes, and was significantly more frequent in eyes with PEX (45 (11)%) than in eyes without PEX (24 (9)%, p<0.03). Eyes with diabetes mellitus (n=32) showed a significantly lower frequency of secondary cataract (11 (11)%) than eyes without diabetes mellitus (39 (8)%, p<0.01). The influences of sex, open angle glaucoma, type of cataract, surgeon, positioning of IOL, and phacoemulsification versus nuclear expression on secondary cataract did not reach statistical significance.
CONCLUSION—The higher frequency of secondary cataract could be considered as another potential complication of cataract surgery in eyes with PEX.

     

Complicated posterior capsulorhexis: aetiology, management, and outcome

BACKGROUND—A 1 year retrospective analysis of 650 patients, who underwent a posterior capsulorhexis on their intact capsules, was performed to examine the incidence of complications, their aetiologies, and the outcome.
METHODS—Data were analysed on 32 patients with complicated capsulorhexis for type of surgery, preoperative and postoperative factors, and relative risk factors for vitreous issue.
RESULTS—There were six patients with vitreous loss. The posterior capsulorhexis was uncontrolled in 14 cases and difficult to perform in 12 cases. Implantation into the capsular bag was possible in all cases. Systemic vascular hazard and old age (over 80 years) were found to be statistically significant risk factors for vitreous loss (p=0.002 and p=0.03 respectively). The mean follow up was 13.5 months (range 4-25 months). One patient developed a retinal detachment and two had a transient clinical cystoid macular oedema. Visual acuity of ≥ 20/40 was obtained in 93% of the patients.
CONCLUSION—Loss of control of the posterior capsulorhexis has a low incidence but can lead to serious problems during surgery. A good knowledge of the technique is necessary to complete the procedure with a posterior capsulorhexis of the optimum size without vitreous loss.

     

Risk of endophthalmitis after cataract extraction: results from the International Cataract Surgery Outcomes study

AIM—To estimate risk of infectious endophthalmitis after cataract extraction in Denmark and to compare results with the risk of this complication in the USA
METHODS—In the national Danish administrative hospital register, 19 426 patients were identified who underwent first eye cataract surgery from 1985 to 1987 and who were 50 years of age or older. Of these, 61 patients had postoperative endophthalmitis.
RESULTS—A 12 month cumulative risk of rehospitalisation for endophthalmitis was estimated at 0.18% (95% CI 0.09-0.26) after extracapsular cataract extraction with lens implant. Advanced age, male sex, intracapsular cataract extraction, and anterior vitrectomy were all associated independently with an increased risk of postoperative endophthalmitis. When restricting the sample to patients aged 65 years or older, in order to allow comparisons to be made with the US National Study of Cataract Outcomes, a 12 month risk of 0.17% (95% CI 0.08-0.25) was estimated. The previously reported US risk of 0.12% is included in the confidence interval of the risk estimated in the Danish sample.
CONCLUSION—Despite considerable differences in the healthcare systems, no statistically significant difference in outcome of surgery as measured by risk of endophthalmitis was shown between Denmark and the USA.