European Association for the Study of Diabetic Eye Complications

Annual Meeting Munich 21-23rd May 2004

Paper Abstracts

MACULAR EDEMA

PERIFOVEOLAR POSTERIOR VITREOUS DETACHMENT AND THE PROFILE OF RETINAL THICKENING IN DIABETIC MACULAR EDEMA.

Ramin Tadayoni, Cécile Roux, Ali Erginay, Belkacem Haouchine, Antoine Catier, Alain Gaudric, Pascale Massin.

Purpose: To establish with OCT whether or not perifoveolar posterior vitreous detachment (PVD) affect the profile of retinal thickening in diabetic macular edema.

Methods: Six scans 6 mm long, forming a radial spoke pattern centered on the patient's fixation point were performed on 47 eyes of 41 consecutive diabetic patients with macular edema. Retinal thickness was measured at the center of macula and at the borders of the scans, 3 mm from the center. The ratio of central macular thickness to mean border thickness was worked out. Eyes were classified according to vitreous detachment, into 2 groups: perifoveolar PVD and others.

Results: The mean age of patients (23 males and18 females) was 63 years. Nineteen eyes (40%) had perifoveolar PVD, and 28 (60%) did not. No case of tractional edema associated with a thickened taut posterior hyaloid was observed. In the perifoveolar PVD group the macula was typically dome-shaped, whereas in others it was more homogeneously thickened. The ratio of central macular thickness to mean border thickness was 2.02±0.34 in the perifoveolar PVD group versus 1.58±0.46 in the others (p=0.0007).

Conclusions: The role of the traction exerted by the vitreous on the macula in the pathogenesis of diabetic macular edema remains controversial. Vitreous traction on the macula, if any, may be maximal during perifoveolar PVD, because it is concentrated on a small surface of the macula. The present study showed that the ratio of central macular thickness to the thickness 3 mm from the center was significantly greater in eyes with perifoveolar PVD than in others. In diabetic macular edema, perifoveolar PVD seems to increase the thickness of the retina in the center of the macula, to which the vitreous is attached.

CURRENT METHODS TO MEASURE DIABETIC MACULAR EDEMA OBJECTIVELY

Aljoscha S Neubauer ¹ , Christos Chryssafis ¹ , Christos Haritoglou, Martin J Thiel ¹ , Anselm Kampik¹ , Michael W Ulbig¹ .

Dept. of Ophthalmology, Ludwig-Maximilians University, Muenchen, Germany¹ .

Purpose: To present an overview of different imaging methods to quantify diabetic macular edema and show their relation to fluorescein angiography.

Methods: In a first step it was aimed at comparing the amount and pattern of fluorescein leakage to retinal thickness maps obtained by both, retinal thickness analyzer (RTA) and optical coherence tomography (OCT). A consecutive series of 30 eyes from 30 patients with diabetic macular edema were included in this comparison. Fluorescein angiography (FA) was performed and the macula divided in 10 subfields as defined by the EDTRS. The amount of leakage in each field and source of leakage was determined. Retinal thickness in each of the 10 fields was measured by OCT (6 radial scans) and RTA (retina map) and compared to the FA findings. In a second step on different patients the measures of the HRT II macular map were compared to those of OCT and RTA.

Results: Foveal retinal thickness is strongest influenced by the overall FA leakage, which is the only significant covariate on multivariate analysis. The source of leakage has a significant correlation with retinal thickness when ischemic cases are excluded. Not the central, but the leakage source between 1500 and 3000 micron from the foveal center shows the highest correlation with foveal thickness. The overall strongest correlation with FA is found with the central OCT measurements. However, a topographic correlation can only be shown for peripheral fields measured by RTA. The HRT II maps correlate with the other objective measures but do not yield absolute thickness measures

Conclusions: Both, OCT and RTA can reliably measure foveal thickening and identify patients for further examination. The HRT maps can also help in determining the thickened area but do not give absolute thickness measures.

EFFECT OF RETINAL THICKNESS ON CENTRAL VISUAL FIELDS IN DIABETIC RETINOPATHY

Christos Chryssafis ¹ , Aljoscha S Neubauer ¹ , Martin J Thiel ¹ , Michael W Ulbig¹ , Anselm Kampik¹ .

Dept. of Ophthalmology, Ludwig-Maximilians University, Muenchen, Germany¹ .

Purpose: While central retinal thickness is known to correlate well with visual acuity, little is known about the effect of posterior pole thickening on the central visual field. This study therefore investigates the correlation of central visual field and retinal thickness in diabetic patients.

Methods: On 39 eyes from 39 patients with systemic diabetes besides a complete clinical examination a 10-2 HFA perimetry and objective measurements of retinal thickness were performed by optical coherence tomography (OCT) and retinal thickness analyzer (RTA). Twenty-six patients had  previously received focal laser therapy, while the remaining 13 did never receive any laser treatment.

Results: A good correlation of visual acuity and central retinal thickness was found with both instruments, OCT and RTA, which correlated highly with each other (r=0.82, p<0.000). Visual acuity also correlated strongly with the mean defect (MD) on visual fields (VF; r=0.50, p=0.001) but not with the pattern standard deviation (PSD). Subgroup analysis was performed on three groups: 1) clinically no diabetic retinopathy, 2) clinically significant macular edema and 3) macular edema after focal laser treatment. Although group 1 had a tendency towards a lower MD and PSD on ANOVA no significant difference was found between the groups. Retinal thickness in group 1 without retinopathy was significantly lower than the other groups. The eyes after laser treatment (group 3) showed a tendency towards lower retinal thickness and better visual acuity than group 2 but the same MD and PSD on VF. A good topographic correlation of VF defects and retinal thickening could be shown.

Conclusions: Central macular retinal thickness is vital for visual acuity. Thickened retina corresponds topographic to scotomas in visual fields. Focal laser treatment seems not to cause significant field defects.

RETINAL  AUTOREGULATION  DECREASES WITH  INCREASING  DIABETIC MACULOPATHY

Christian Alcaraz Frederiksen¹ , Peter Jeppesen¹  and Toke Bek¹

¹. Dept of Ophthalmology, Aarhus University Hospital, Denmark

Purpose: To study the diameter response of retinal arterioles in patients with different stages of diabetic maculopathy during a rise in the arterial blood pressure.

Methods: Twenty-four type 2 diabetic patients were studied. The patients consisted of three groups matched for age, gender, and duration of diabetes. Group (A) no retinopathy. Group (B) 1-4 microaneurysms, Group (C) hard exudates in the macula area. The diameter changes of a  retinal arteriole were measured continuously using the Retinal Vessel Analyzer (RVA, Imedos, Germany) before, during,  and  after  a  rise  in blood pressure  induced by  isometric exercise when  lifting a hand weight  in one arm. Blood pressure was measured on  the other arm  using  cuff  technique

Results:  The  isometric  exercise  induced  an  increase  in  blood pressure of averagely 25.8±2.6 mmHg with no difference between the studied groups. Retinal

autoregulation showed a significant decrease with increasing degree of diabetic maculopathy (p=0.03, ANOVA). The diameter changes were –1.58%±0.82 in group A indicating preserved autoregulation,  0.70%±0.63  in  group  B,  and  1.05%±0.66  in  group  C  indicating  loss  of autoregulation.

Conclusions: The results are in accordance with previous studies suggesting that  impaired autoregulation may be  involved  in  the pathogenesis of diabetic maculopathy. This can be estimated non-invasively and in vivo using the Retinal Vessel Analyzer.

DIABETIC  MACULAR  TRACTION  SYNDROME

Jiri Rehak, Oldrich Chrapek, Zuzana Pracharova Dept. of  Ophthalmology, University Hospital, Olomouc, Czech Republi

Purpose:   To evaluate effect of pars plana vitrectomy on visual acuity and development of macular edema in diabetic macular traction syndrome.

Methods:   In the period of July 2002 to January 2003, we identified 35 diabetics in total, with clinically significant macular edema. The OCT examination was carried out with all of the patients. In 5 patients, the diabetic macular traction syndrome was detected and these patients underwent pars plana vitrectomy. The monitoring period was 6 months

Results:   The visual acuity (VA) improved 4 times at least by one line of the Snellen chart  and 1 time the VA worsened in relation to the progress of ischaemic changes in macula. It was necessary to perform supplementary direct photocoagulation in one of the improved patients, or, for the most part, intervention with laser after vitrectomy was not necessary. Development of the macular edema after operation: before operation, in all of the 5 patients, cystoid macular edema (CME) was present, in one patient with a significant ischaemic component. The CME practically completely disappeared in 3 cases, in one case a significant reduction occurred and in one case the CME did not change (the patient with ischaemic macula). We re-operated once due to development of an epimacular membrane 6 months after the first operation 

Conclusion:   We recommend the OCT examination for all the patients with the diabetic macular edema. In the case of development of the macular traction syndrome, we recommend pars plana vitrectomy, which in 80 % improves the VA and significantly reduces macular edema. In the case of the diabetic macular traction syndrome, the anatomic improvement, however, does not always lead to vision improvement.

REPEATED INTRAVITREAL TRIAMCINOLONE INJECTIONS FOR TREATMENT OF DIABETIC MACULAR EDEMA : RESULTS AT ONE YEAR.

P. Massin, C Mazit, A Erginay, R Benosman, F Audren , B Haouchine, A Gaudric Ophthalmology Department, Hôpital Lariboisière, Paris

Purpose: To assess the efficacy of repeated intravitreal triamcinolone acetonide (TA) injections for refractory diabetic macular edema (DME) , at one year.

Methods: Twenty three eyes of 19 diabetic patients ( 11 on insulin) were included in the study. They exhibited DME that persisted despite grid laser photocoagulation more than 6 months previously. No eyes had active proliferating diabetic retinopathy. Blood pressure was less than 150/80 mm Hg and HbA21c, less than 8.5%. Before inclusion IOP response was tested by instilling 0.1% dexamethasone drops thrice daily for one month. Eyes whose IOP rose above 25 mmHg were not included. In the 23 eyes, 4mg TA in 0.1ml was injected transconjonctivally into the vitreous cavity. Reinjection was allowed 6 months later in case of DME recurrence. A mean of 2.1 injections was performed during follow-up. The efficacy of TA was checked by measuring Best Corrected Visual Acuity (BCVA) on ETDRS optotypes, and macular thickness on OCT mapping ( OCT1, A5 software, Zeiss Instruments , Dublin CA). Patients were examined monthly.

Results: One month after the first injection, macular thickness had decreased significantly, in 22/23 cases. At 5.7 months DME had recurred in 21 eyes, and either one or two reinjections were then performed at various interval. Mean macular thickness decreased from 566 µm ± 146 before treatment to 210µm ±44 at one month, and to 292µm±136 at one year (p=0.0002). BCVA increased from 43±12.7 ETDRS letters to 52±11 at one month, and 47±13 at one year (NS). IOP rose after 23/48 injections. After the first injection 12/23 eyes (50%) exhibited IOP > 21 mmHg. IOP was always controlled by topical treatment. Lens opacity increased in 10/21 phakic eyes, and 4 cataracts were operated on during the year of follow-up.

Conclusion: Intravitreal injection of 4 mg TA significantly improved DME refractory to grid laser treatment, at least for several months. DME recurred in almost all cases between 3 and 9 months after the first injection (mean 5.7±1.7). Reinjection maintained the improvement until one year thereafter. VA increased moderately at 3 months but progression of cataract limited this result at one year. Further studies are needed to assess the long term value of TA treatment for DME.

DIFFUSE DIABETIC MACULAR EDEMA: PATHOLOGY AND IMPLICATIONS FOR SURGERY

Arnd Gandorfer, Matthias Rohleder, Christos Haritoglou, Michael Ulbig, Sabine Grosslfinger, Anselm Kampik Augenklinik der Ludwig-Maximilians-Universität, München

Purpose: To investigate the ultrastructure of the vitreomacular interface in patients with diffuse diabetic macular edema.

Methods: Fifty-five consecutive patients with diffuse diabetic macular edema underwent vitrectomy with en-bloc removal of the inner limiting membrane and epimacular tissue. Six patients were operated on both eyes. Sixty-one specimens harvested during vitrectomy were analyzed by electron microscopy.

Results: Preoperatively, a thickened premacular cortical vitreous was present in 47 eyes. Native vitreous collagen with single cells interspersed within the collagenous layer or a cellular monolayer were the ultrastructural features in these eyes. Twentythree eyes showed an epimacular membrane. In eyes with obvious signs of tangential vitreomacular traction, multilayered membranes situated on a layer of native vitreous collagen were found. Fibroblasts and fibrous astrocytes were the predominant cell types; myofibroblasts and macrophages were also present. Sixty out of 61 specimens showed native vitreous collagen covering the inner limiting membrane. Macular edema resolved in 58 eyes and persisted in 3 eyes. No recurrent fibrocellular proliferation was observed during the follow-up period of 18 months (mean; 3 to 56 months).

Conclusion: The vitreomacular interface in eyes with diffuse diabetic macular edema is characterized by a layer of native vitreous collagen and a varying cellular component. Tangential vitreomacular traction is associated with multilayered membranes situated on a layer of vitreous collagen. Resolution of macular edema does not depend on the presence of contractile membranes. In eyes without tangetial traction, complete removal of epimacular tissue also leads to fluid resorption.