Morphometric analyses in patients treated with subthreshold laser photocoagulation for central serous chorioretinopathy

BACKGROUND AND OBJECTIVE

To analyze changes in selected parameters in optical coherence tomography (OCT) after subthreshold laser coagulation (ST-LP) in patients with central serous chorioretinopathy (CSCR).

MATERIALS AND METHODS

Fifty-four eyes of 49 patients with CSCR were included in the study. Each patient underwent therapy with ST-LP with a frequency-doubled Neodym-YAG Laser and OCT imaging. In OCT the thickness of the central subfield, cube volume, average cube thickness, volume under the ETDRS grid, and average thickness under the ETDRS grid were collected.

RESULTS

Decreases in total OCT volume and central retinal subfield thickness were statistically significant (p < 0.05). Possible correlations were observed between visual acuity at V3 (3 months after ST-LP) and Baseline and between central retinal subfield thickness at V1 (4 weeks after ST-LP) and visual acuity at BL.

CONCLUSION

A decrease in retinal thickness and retinal volume could be shown after ST-LP. Central retinal subfield thickness measured by OCT could be a more sensitive measure than mean retinal thickness or macular volume for early detection of disease recurrence occurring in some patients 3 months after ST-LP.

Chemical and Physical Stability of Perfluorocarbons with Laser Treatment

Physical and toxicological aspects of different perfluorocarbons and semifluorinated compounds are discussed. The urgent need for ultrapurification of perfluorocarbons is demonstrated. In vitro laser treatment simulating physiological conditions of two ultrapurified perfluorocarbons used for temporary tamponade and mechanical fixation of unfolded retina in case of giant tears, and one semifluorinated diether resulted in no detectable chemical alteration. Cytotoxic examinations of both laser treated and untreated probes showed no difference in cell proliferation.

[New Possibilities in Retinal Diagnostics Using OCT Angiography]

BACKGROUND

Instruments for using OCT angiography (OCTA) in daily clinical practice have recently become available. The aim of this paper is to report the possibilities, advantages and limitations of OCTA in the clinical diagnosis of diseases of the posterior segment of the eye.

PATIENTS/METHODS

Patients with diabetic retinopathy, retinal vascular occlusions, and age-related macular degeneration who had been assigned to fluorescein angiography (FA) additionally underwent an AngioPlex™-OCTA examination, which captures a 6 × 6 mm scanning area centred on the fovea. If deemed necessary, 3 × 3 mm volume scans were created in regions of interest. The findings of FA and OCTA were correlated and compared.

RESULTS

The OCTA procedure took only a few seconds, was easily integrated into the standard OCT diagnostic imaging procedure, and delivered highly detailed, three dimensional images of the entire microvasculature of the retina and choroid. Microvascular changes, such as microaneurysms, intraretinal microvascular abnormalities, non-perfused areas, alterations in the foveal avascular zone (FAZ) and neovascularization were reliably detected. Overall, OCTA results were in good agreement with the results of the FA. Additionally, OCTA provided more detailed and three dimensional information and thus permitted a better assessment of the spatial extension of microvascular abnormalities. Due to OCTA's limited scanning area, vascular alterations in the mid-periphery were detected only if their location had already been determined by FA. Although OCTA does not show leakage, macular oedema can be diagnosed from OCTA, together with OCT thickness measurements.

CONCLUSION

OCTA provides important three dimensional information on vascular alterations and is already an indispensable diagnostic method. As the procedure takes just a few seconds and can be performed non-invasively, OCTA is well suited as a monitoring method and may allow early diagnosis. In this sense, prospective studies are required to determine precise OCTA analytical strategies for specific diseases. It is very likely that OCTA will revolutionise the diagnosis of retinal and choroidal diseases; however, it is not yet clear estimated to what extent it will replace FA.

[Basic in vitro studies on VEGF inhibition with aflibercept: similarities and differences to other VEGF-binding therapeutic proteins]

Patients suffering from various retinal diseases benefit from therapies directed against the vascular endothelial growth factor (VEGF). Aflibercept (Eylea) is another VEGF-binding protein available for intravitreal injection, in addition to the antibody bevacizumab (Avastin) and the F(ab) fragment ranibizumab (Lucentis). Aflibercept's distinct structure and broader binding specificity may have clinically relevant consequences, which is supported by basic in vitro studies and observations in animal eyes. All pathological processes involving neovascularisation are driven by the dominant action of VEGF, but other factors including placenta growth factor (PlGF), a mitogenic protein for retinal endothelial cells, potentially modulate its effects. Aflibercept is an inhibitor of both VEGF and PlGF and therefore may have superior therapeutic effects in some cases. However, whether or not aflibercept's broader binding specificity or different affinities for the different VEGF-binding proteins to VEGF result in substantially diverse therapeutic efficiencies has not yet been clarified. In vitro studies confirm that aflibercept efficiently prevents or normalises VEGF-stimulation of retinal cells and disturbance of their barrier function. These experiments also show that aflibercept is taken up by important retinal cell types and affects their normal function, i.e., migration of endothelial cells and phagocytosis of pigment epithelial cells. In accordance with a role of the Fc domains of aflibercept and bevacizumab, substantial amounts of both proteins are internalised, whereas only a small portion of ranibizumab enters the cells. Internalisation and storage by ocular cells, also observed in vivo after intravitreal injection into eyes of monkeys, may result in not yet recognised side effects during long-term treatment of patients with certain VEGF-binding proteins.

[Treatment of diabetic macular oedema with the VEGF inhibitors ranibizumab and bevacizumab: conclusions from basic in vitro studies]

Diabetic macular oedema (DMO) which may occur at all stages of diabetic retinopathy (DR) is a severe vision-threatening complication. In most cases, laser treatment does not improve visual acuity. Therefore research in ophthalmology focuses on the improvement of the prognosis of DMO patients with a drug-based DMO therapy. Vascular endothelial growth factor (VEGF) is considered the most important therapeutic target because this growth factor also is the most potent permeability factor affecting the inner retinal barrier formed by endothelial cells (ECs). Compared to its angiogenic stimulation of proliferation and migration of ECs, effects of VEGF on permeability have not been studied in all details. In vitro investigations on the behaviour of primary or immortalised retinal endothelial cells confirmed the key role of VEGF in the regulation of the permeability of the inner retinal barrier. Despite the presence of a variety of other factors found to be elevated in DR, a VEGF-disrupted barrier can be completely restored with the VEGF-inhibiting ranibizumab (Lucentis®) and bevacizumab (Avastin®) when applied at clinically achievable concentrations. The antibody bevacizumab, but not the antibody fragment ranibizumab, accumulates in both retinal EC and pigment epithelial cells during prolonged treatment. This observation might be relevant because patients are often treated for several years and additional long-term side effects may be recognised in the future.

[Mechanisms of retinal neurodegeneration as a result of diabetes mellitus]

Diabetic retinopathy is characterised by microvascular damage to the retina caused by diabetes mellitus. Early vascular findings are microaneurysms and a breakdown of the blood-retina barrier. Recent studies indicate that neurodegeneration and neuroinflammation of the retina play an important role in the pathogenesis of diabetic retinal changes. They can occur early and preceed vascular changes. Important features of neurodegeneration of the retina are apoptosis and glia activation. This results in the loss of neuroretinal tissue.

New approaches for the treatment of diabetic macular oedema: recommendations by an expert panel

The current standard therapy for patients with diabetic macular oedema (DME)--focal/grid laser photocoagulation--usually does not improve impaired vision, and many patients lose vision despite laser therapy. Recent approval of ranibizumab by the European Medicines Agency to treat visual impairment due to DME fulfils the previously unmet medical need for a treatment that can improve visual acuity (VA) in these patients. We reviewed 1- and 2-year clinical trial findings for ranibizumab used as treatment for DME to formulate evidence-based treatment recommendations in the context of this new therapy. DME with or without visual impairment should be considered for treatment when it fulfils the Early Treatment Diabetic Retinopathy Study (ETDRS) criteria for clinically significant oedema. For DME with centre involvement and associated vision loss due to DME, monthly ranibizumab monotherapy with treatment interruption and re-initiation based on VA stability is recommended. Laser therapy based on ETDRS guidelines is recommended for other forms of clinically significant DME without centre involvement or when no vision loss has occurred, despite centre involvement. Because these recommendations are based on randomised controlled trials of 1-2 years duration, guidance may need updating as long-term ranibizumab data become available and as additional therapeutic agents are assessed in clinical trials.

[Photodynamic therapy with verteporfin in occult choroidal neovascularization in age-related macular degeneration]

OBJECTIVE

We investigated retrospectively the clinical outcome of photodynamic therapy (PDT) with verteporfin (Visudyne) in patients with exudative age-related macular degeneration (ARMD) and subfoveal occult choroidal neovascularization (OCN).

METHODS

77 consecutive patients (90 eyes) with OCN were retrospectively analysed using a standardised protocol. It included best corrected visual acuity (BCVA) pre- and post-PDT, greatest linear dimension of OCN (GLD), ophthalmoscopic findings, optical coherence tomography (OCT), fundus photography and fluorescein angiography (FAG). The findings were descriptively analysed by Spearman rank correlation and cross-tabulation.

RESULTS

Age ranged from 52 to 92 years (median: 79 years). 7 (8 %) of 90 PDT eyes gained > or = 2 lines, 67 (74 %) eyes stabilised with +/- 1 line. 17 eyes (18 %) showed a deterioration with loss of > or = 2 lines. BCVA of all cases was pre-PDT 0.33 (+/- 0.2), post-PDT 0.27 (+/- 0.2, p < 0.05), in the improvement group pre-PDT 0.4, post-PDT 0.7 in the stable cases pre-/post-PDT 0.3 and in the deterioration group pre-PDT 0.4 and post-PDT 0.2. GLD of all cases was pre-PDT 3.91 mm (minimum: 0.76 mm, maximum: 5.43 mm). From 86 eyes with OCT follow-up of at least 3 months 51 (60 %) had dry macula after last PDT and 35 (40 %) persistent macular edema (ME) in OCT. In 21 eyes (23 %) with leakage of fluorescein after last PDT, treatment was terminated. 10 eyes (47 %) had retinal angiomatous proliferation stage III, of these, 6 eyes presented with retinochoroidal anastomoses. 4 eyes (18 %) showed after PDT retinochoroidal anastomoses, 2 (10 %) vitreomacular traction in epiretinal membrane of the macula, 2 (10 %) had a tear of the retinal pigment epithelium, 1 (5 %) eye had a gain of GLD > 7200 microm, in 1 eye (5 %) BCVA was < 0.05 and in 1 eye (5 %) treatment was stopped at request of the patient.

CONCLUSIONS

According to our study PDT might be helpful in the treatment of OCN in ARMD patients for stabilisation but not for improvement of BCVA. Results from large multicentre studies show that concerning BCVA ranibizumab (Lucentis) is superior to PDT in OCN. Further studies are required to investigate the outcome of combined therapy with PDT and VEGF inhibitors for reducing the number of treatments or the number of recurrences of choroidal neovascularisation.

[Different indications of photodynamic therapy in ophthalmology]

BACKGROUND

Photodynamic therapy (PDT) in eye disease was approved 10 years ago for age-related macular degeneration (AMD). Thereafter it was approved for choroidal neovascularisation (CNV) in pathological myopia. The treatment regimen is based on two prospective, multicentre trials (TAP and VIP studies).

MATERIAL AND METHODS

In the meantime PDT has been successfully used also in several other ocular diseases. PDT is minimally invasive and has an excellent side effect profile. Different diseases and their treatment with PDT are discussed.

RESULTS

The treatments of idiopathic CNV, secondary CNV in inflammatory diseases of the retina and choroid, choroidal haemangioma, vasoproliferative tumours, malignant melanoma of the choroid, and central serous chorioretinopathy with PDT are described. In most patients the disease progression can be stopped and in some the PDT treatment results in visual improvement. The prognosis is better in patients with early disease detection and small lesions.

CONCLUSION

Several retinal and choroidal diseases can be treated successfully with PDT. Except for AMD and pathological myopia, PDT is an off label treatment.

[In vitro studies on the mechanism of action of VEGF and its inhibitors]

VEGF expression and signalling are deregulated in diabetic retinopathy. Cellular processes like migration and proliferation as well as control of the permeability of the endothelium by VEGF are regulated as a consequence of its binding to the VEGF receptor 2. Proteins forming tight junctions between microvascular endothelial cells of the retina are delocated to the cytoplasm after treatment with VEGF(165), likely leading to the breakdown of the blood-retina barrier. VEGF-inhibitors such as a VEGF-aptamer (modified RNA-oligonucleotide; pegaptanib) or specific antibodies/antibody fragments (bevacizumab, ranibzumab) which directly interfere with the interaction of VEGF with its receptors are considered to be promising novel therapeutics to treat diabetic retinopathy and age-related macular degeneration. In vitro studies using microvascular endothelial cells will help to clarify the mechanisms of action of VEGF and its inhibitors. In particular, the influence of VEGF isoforms and the inhibitor ranibizumab on the proliferation and migration of bovine retinal microvascular endothelial cells was studied, as well as the rearrangement of tight-junction proteins after treatment of the cells with VEGF(165) and specific inhibitors. In addition to a review of recent publications in the field, primary data from our own studies are presented in this article.

[Effect of VEGF165 and the VEGF aptamer pegaptanib (Macugen) on the protein composition of tight junctions in microvascular endothelial cells of the retina]

BACKGROUND

VEGF signalling is deregulated in diabetic retinopathy. Therefore, VEGF inhibitors like the modified RNA-oligonucleotide pegaptanib (VEGF aptamer, Macugen) which inhibits the interaction of VEGF(165) with its receptors, are currently being discussed as therapeutic options in the treatment of diabetic retinopathy. VEGF(165) does not only stimulate the proliferation and migration of endothelial cells but also induces delocalization of occludin which is part of the so-called tight junctions of endothelial cells likely associated with the breakdown of the blood-retina barrier.

METHODS AND MATERIAL

To further investigate the mechanisms of action of VEGF and its inhibitor, we studied the influence of VEGF(165) and/or pegaptanib on the protein composition of tight junctions in immortalised endothelial cells of the bovine retina (iBREC) by immunofluorescence staining.

RESULTS

The tight junction proteins ZO-1, occludin and claudin-5 are strongly expressed at the plasma membrane in confluent iBREC, but are located in the cytoplasm in non-confluent cells. In the presence of 50 ng/ml VEGF(165), occludin was found in the cytoplasm after 1 to 2 days, whereas claudin-5 was not and ZO-1 was only weakly influenced. However, after addition of 33 microg/ml pegaptanib for 24 h to VEGF(165)-treated iBREC, all tight junction proteins tested were again strongly expressed in the plasma membrane.

CONCLUSION

These results confirm an important role of tight junction proteins in the mechanisms of action of VEGF and pegaptanib on endothelial cells.

Okuläre Manifestation einer infektiösen Endokarditis

BACKGROUND

Infectious infiltrations of the retina and the vitreous in endogenous infections such as septicaemia are rare.

PATIENT

A 42-year-old woman presented complaining about a defect of her visual field in the right eye. The patient reported about a feeling of illness and high temperature up to 39.5 degrees C since two weeks.

RESULTS

At the first examination the patient had a best corrected visual acuity of 1.25 in her right eye and 1.0 in her left eye. A focal infiltration of the retina with a circumscribed haemorrhage was found on ophthalmoscopy and fluorescein angiography, located on the temporal superior vein. One day later a circumscribed vitreous infiltration was seen in this area. The ophthalmological findings and the fever of unknown origin led to the tentative diagnosis of a retinal infiltration due to an infectious disease. Internal examinations revealed a subacute endocarditis caused by viridans streptococci. Under intravenous antibiotic treatment the infiltration of the retina and vitreous declined quickly. A complete healing of the ophthalmological findings was found 3 weeks later.

CONCLUSIONS

Since the subacute endocarditis in infections caused by viridans streptococci is characterized by a lingering start of the disease with high temperature of unknown origin and an unspecific feeling of illness, the ophthalmological findings can manifest itself before the diagnosis of the underlying disease is made. Complications such as blindness after fulminant endophthalmitis and death can be avoided through quick diagnosis and treatment.

[Comparison of Preferential Hyperacuity Perimeter (PHP) test and Amsler grid test in the diagnosis of different stages of age-related macular degeneration]

BACKGROUND

Age-related macular degeneration (ARMD) is the leading cause of blindness in people over 65 years of age. A rapid loss of vision occurs especially in cases with choroidal neovascularisation. Early detection of ARMD and timely treatment are mandatory. We have prospectively studied the results of two diagnostic self tests for the early detection of metamorphopsia and scotoma, the PHP test and the Amsler grid test, in different stages of ARMD.

PATIENTS AND METHODS

Patients with ARMD and best corrected visual acuity of 6/30 or better (Snellen charts) were examined with a standardised protocol, including supervised Amsler grid examination and PHP, a new device for metamorphopsia or scotoma measurement, based on the hyperacuity phenomenon in the central 14 degrees of the visual field. The stages of ARMD were independently graded in a masked fashion by stereoscopic ophthalmoscopy, stereoscopic fundus colour photographs, fluorescein angiography, and OCT. The patients were subdivided into 3 non-neovascular groups [early, late (RPE atrophy > 175 microm) and geographic atrophy], a neovascular group (classic and occult CNV) and an age-matched control group (healthy volunteers).

RESULTS

140 patients, with ages ranging from 50 to 90 years (median 68 years), were included in the study. Best corrected visual acuity ranged from 6/30 to 6/6 with a median of 6/12. 95 patients were diagnosed as non-neovascular ARMD. Thirty eyes had early ARMD (9 were tested positive by the PHP test and 9 by the Amsler grid test), and 50 late ARMD (positive: PHP test 23, Amsler grid test 26). The group with geographic atrophy consisted of 15 eyes (positive: PHP test 13, Amsler grid test 10). Forty-five patients presented with neovascular ARMD (positive: PHP test 38, Amsler grid test 36), 34 volunteers served as control group (positive: PHP test 1, Amsler grid test 5).

CONCLUSIONS

The PHP and Amsler grid tests revealed comparable results detecting metamorphopsia and scotoma in early ARMD (30 vs. 30 %) and late ARMD (46 vs. 52 %). However, the PHP test more often revealed disease-related functional changes in the groups of geographic atrophy (87 vs. 67 %) and neovascular ARMD (84 vs. 80 %). This implies that the PHP and Amsler grid self tests are useful tools for detection of ARMD and that the PHP test has a greater sensitivity in the groups of geographic atrophy and neovascular AMD.

[Retinal angiomatous proliferation in age-related macular degeneration]

BACKGROUND

Angiomatous proliferation in ARMD originates from the retina and extends into the subretinal space. Retinal angiomatous proliferation (RAP) is diagnosed with angiography. This study investigates the characteristics of RAP in optical coherence tomography (OCT) and correlates them with clinical and fluorescein angiographic findings.

METHODS

327 consecutive patients with age-related macular degeneration (ARMD) were retrospectively examined using a standardised protocol. The protocol included best corrected visual acuity (BCVA), binocular ophthalmoscopy, fundus photography, fluorescein angiography (FAG) and OCT. The OCT and angiographic findings were graded in 3 RAP stages.

RESULTS

32 of 327 (9.79 %) patients (45 eyes) had RAP. The age ranged from 56 to 90 years (median: 79 years). 9 eyes presented RAP stage I, 23 stage II and 13 stage III. BCVA ranged from 0.01 to 0.7 (median: 0.2). OCT foveal minimum was 136 to 722 microns (median: 327). 33 (73 %) eyes showed a detachment of retinal pigment epithelium (RPE). Macular oedema was found in 43 (96 %) eyes. Cystoid macular oedema was seen in 36 (80 %) eyes. In stage II, 22 eyes (96 %) showed an RPE detachment, in stage III 11 eyes (85 %). 11 (85 %) eyes in stage III showed retinal-choroidal anastomosis.

CONCLUSIONS

RAP was found in 9.79 % of the patients with ARMD. The OCT is helpful in detection of RPE detachment, macular oedema and cystoid changes in RAP. RAP and retinal-choroidal anastomosis should be identified because of the possibly poor prognosis.

CAR-Syndrom (carcinoma-associated retinopathy syndrome) assoziiert mit einem Adenokarzinom der Zervix

BACKGROUND

CAR is a rare paraneoplastic syndrome. It is most commonly associated with small-cell carcinoma of the lung. Specific autoantibodies exist not only against the retina but also against other ocular structures. They induce apoptotic death of retinal photoreceptor cells.

CASE REPORT

We report about a 68-year-old patient who presented in February 2003 with progressive visual dysfunction including visual acuity loss and visual field defects of unknown origin, which first manifested in the year 1998.

RESULTS

We found a visual acuity of 0.1 in both eyes and concentric visual field defects. The scotopic and photopic electroretinogram was markedly reduced. Uveitis intermedia in both eyes, narrowing of the vessels, especially of the arterioles, optic atrophy and window defects in the retinal pigment epithelium were observed on fluorescein angiography. Due to the patient's report about a resection of an adenocarcinoma of the cervix in June 2002, she was diagnosed as having CAR syndrome. Serologic screening by Western blot analysis revealed different specific autoantibodies against retinal proteins. The patient was treated with corticosteroid pulse therapy. The follow-up showed stable findings.

CONCLUSIONS

In patients with progressive visual loss, concentric visual field defects and pathological electroretinogram as well as evidence of uveitis, a CAR syndrome has to be ruled out. One has to take into consideration that visual dysfunction can appear before the primary cancer is diagnosed.

Rubeosis iridis als Komplikation bei Zentralarterienverschluss

BACKGROUND

Iris neovascularization (IN) with a secondary angle closure glaucoma is a complication of central retinal artery occlusion (CRAO). Its incidence is greatly underestimated.

MATERIALS AND METHODS

In a retrospective study we analyzed all patients with CRAO seen within 2 years who were treated in our department. We looked especially for the frequency of the occurrence of IN.

RESULTS

In 27 patients with CRAO, 5 developed an IN with a secondary neovascular glaucoma with high intraocular pressure. Thus, the frequency of IN was 18 % in our patients. The IN occurred 2 months to 2 years after the occlusion. Visual acuity in three eyes was between 1/20 and light perception and two eyes had no light perception. In all cases a panretinal laser treatment was performed. Three eyes were additionally treated with a peripheral retinal cryocoagulation and cyclophotocoagulation. In the histories of these patients, diabetes mellitus and arterial hypertension were found.

CONCLUSIONS

In previous studies it has been shown, that ischemia/reperfusion injuries of the retina after CRAO predispose to IN (incidence 3 - 18 %). Although it has been shown that the majority of IN occurs within three months, our data show that IN may occur as a severe complication of CRAO even later. Patients should be followed-up closely (including gonioscopy), to diagnose the occurrence of IN early. Recommended treatment is panretinal laser coagulation or -- in the case of a secondary angle closure glaucoma -- cyclophotocoagulation, respectively.

Medikament�se Therapie der diabetischen Retinopathie

Chronic overproduction of growth hormone and insulin-like growth factor 1 play an important role in the pathogenesis of diabetic retinopathy. Somatostatin receptors are the targets of somatostatin analogues such as octreotide in the treatment of diabetic retinopathy. Octreotide has shown promise as a safe and effective treatment for advanced diabetic retinopathy and diabetic macular edema. One important pathomechanism in the development of diabetic complications is the activation of protein kinase C induced by high glucose due to an increased diacylglycerol level. The development of a selective PKCss inhibitor enables a new therapeutic approach for the treatment of diabetic retinopathy. Ongoing prospective clinical studies are investigating if treatment with specific PKCss inhibitors can prevent the progression of diabetic retinopathy and diabetic macular edema. The intravitreal injection of triamcinolone acetonide leads to at least temporary improvement of the diffuse diabetic macular edema. Side effects are increase of intraocular pressure, cataract, and endophthalmitis.

Vergleich der optischen Kohärenzmethode (Zeiss IOL-Master) mit zwei ultrasonographischen Biometrieverfahren zur Kunstlinsenkalkulation nach Phakoemulsifikation im klinischen Alltag

BACKGROUND

The aim of this work was to investigate the accuracy of prediction of three different biometric methods for the calculation of posterior chamber intraocular lenses.

METHODS

In 59 consecutive patients who underwent extracapsular cataract-extraction with posterior chamber intraocular lens implantation, we compared the refractive results at the first day (D1) and 6 weeks (W6) after surgery with the calculated refraction of three biometric methods: the Carl Zeiss "IOL-Master 99" (IOLM), the Biovision "Echograph Class 1 - Type B" (BIOV) and the Allergan Humphrey "Ultrasonic Biometer Mod. 820" (AHUB). For statistical calculation box-plots, the Wilcoxon signed-rank test and linear regression analysis were used.

RESULTS

In all patients the mean of the postoperative refraction was - 0.07 D (SD: 1.41) at day 1 and 0.12 D (SD: 1.18) at week 6. Compared to the postoperative refraction at week 6, the calculated refractive values were higher in all three measuring devices: IOLM: + 0.28 D (SD: 0.67), BIOV: + 0.60 D (SD: 0.88), AHUB: + 0.26 D (SD: 0.92). There were no statistically significant differences between IOLM and BIOV, or respectively, AHUB and BIOV (p < 0.0001), but a significant difference was found between IOLM and AHUB, (p = 0.906). To adjust for systematic differences of the agreement, one can calculate the postoperative refraction at week 6 (REF6) from IOLM by using the linear regression formula: REF6 = 1.1 x IOLM + 0.3.

CONCLUSION

A comparison between the three biometric methods and the refractive results at day 1 and week 6 after cataract surgery with implantation of a posterior chamber intraocular lens showed that the calculated mean values obtained from the three biometric methods are higher than the real postoperative refraction. Calculations using the Zeiss IOL-Master and the Allergan Humphrey Ultrasonic Biometer are closer to the patient's postoperative refraction than calculations using the Biovision Echograph.

Prospektiver Vergleich des neuen Impressionstonometers TGDc-01 und des Non-Kontakt-Tonometers PT 100 mit der etablierten Goldmann-Applanationstonometrie

BACKGROUND

This study aimed to compare the results of newer tonometric techniques with standard tonometry for the examples of the Goldmann applanation tonometry (GAT), the indentation tonometer "TGDc-01" and the non-contact tonometer "PT 100".

PATIENTS

The study was conducted on a total of 52 healthy subjects. The IOP was measured in each subject on both eyes with all three methods. There were 27 males (51.9 %), 25 females (48.1 %) with an average age of 28.5 years, with a minimum of 13 and a maximum of 79 years.

RESULTS

There was no statistically significant difference between the non-contact and the Goldmann applanation tonometry. The measurements were 0.4 mmHg lower, no difference for the left or right side was seen. For IOP higher than 15 mmHg - 0.88 mmHg lower and for IOP lower 15 mmHg - 0.15 mmHg. The results for the "TGDc01" were 0.82 mmHg lower than GAT, the standard deviation was a little higher with 2.9 mmHg compared to 2.67 mmHg for GAT. For IOP higher than 15 mmHg they rose up to - 2.28 mmHg, for IOP lower than 15 mmHg the results for "TGDc-01" were only - 0.2 mmHg lower. There was also an effect with respect to the side, on the right eye the difference was significant with 3.03 mmHg (p = 0.006), in contrast to the left eye with 2.69 mmHg (p = 0.235). For "TGDc01" the standard deviation was higher with 2.9 mmHg compared to 2.6 mmHg for "PT 100".

CONCLUSIONS

The non-contact tonometer showed no clinical relevant difference compared with GAT for measuring IOP. The indentation tonometer showed differences for precision, for higher tension IOP the measurement was lower compared with GAT. There was also a significant side difference using the "TGDc-01".

Elevated serum levels of N(epsilon)-carboxymethyl-lysine, an advanced glycation end product, are associated with proliferative diabetic retinopathy and macular oedema

AIMS/HYPOTHESIS

Diabetic retinopathy is a frequent microvascular complication. In search of novel risk markers, we analysed the association between serum levels of the major advanced glycation end product N(epsilon)-carboxymethyl-lysine (CML) and prevalence of advanced stages of retinopathy in Type 2 diabetic patients without nephropathy.

METHODS

We carried out a case-control study of Type 2 diabetic patients with and without advanced stages of diabetic retinopathy. Retinopathy and macular oedema were defined according to standard criteria. Serum levels of CML were estimated by means of a novel competition-based ELISA assay.

RESULTS

Serum levels of CML were significantly different between age-matched controls (n=792; mean value +/- SD: 521+/-134 ng/ml), Type 2 diabetic patients without severe retinopathy (821+/-141 ng/ml; p<0.0001) and Type 2 diabetic patients with proliferative retinopathy (1182+/-346 ng/ml; p<0.0001). Levels of CML greater than 1000 ng/ml represented a 25-fold increase in risk of proliferative retinopathy. Receiver operating characteristics analysis revealed a CML threshold of 1087 ng/ml (100% sensitivity, 93% specificity) for clinically significant macular oedema.

CONCLUSIONS/INTERPRETATION

High serum levels of CML were associated with advanced stages of retinopathy. Serum levels were shown to be a progressive risk marker, whereby a level of more than 1000 ng/ml induced a 25-fold increase in risk of proliferative retinopathy and clinically significant macular oedema. Our data suggest that serum levels of CML provide a novel risk marker for advanced stages of diabetic retinopathy in Type 2 diabetic patients.

Einfluss von Wachstumsfaktoren auf die Differenzierung von porcinen Linsenepithelzellen

BACKGROUND

Besides cell proliferation, transdifferentiation of lens epithelial cells (LECs) to myofibroblasts is one of the mechanisms of secondary cataract formation. This process is characterized by increased expression of alpha-smooth muscle actin (alpha-SMA). This study investigated the influence of bFGF, TGF-beta2, EGF and IGF-1 on the expression of alpha-SMA in porcine LECs.

MATERIALS AND METHODS

Porcine LECs were cultured for 7 days in serum-free medium without or with 1 to 50 ng/ml bFGF, TGF-beta2, EGF or IGF-I. Alpha-SMA was detected immunocytochemically with a mouse monoclonal antibody, and the relative numbers of alpha-SMA-positive cells were calculated. Statistical analysis was performed using Student's unpaired t-test.

RESULTS

The ratio of alpha-SMA-positive cells cultured for 7 days in serum-free medium was 36 +/- 11.9 % (mean +/- SD). BFGF significantly reduced this ratio in a dose-dependent manner to 11.2 +/- 7.3 % at a concentration of 50 ng/ml (p < 0.0001). EGF reduced the ratio significantly to 25.1 +/- 15.7 % (p = 0.05) when 50 ng/ml were applied. IGF-1 (10 ng/ml) reduced the relative numbers of transdifferentiated cells to 16.8 +/- 5.8 %, but the reduction was not statistically significant (p = 0.0787). TGF-beta2 (50 ng/ml) slightly increased the relative number of alpha-SMA-positive cells to 44.2 +/- 13.8 %. However, this increase was not significant (p = 0.1202) during a culture period of 7 days.

CONCLUSIONS

BFGF and EGF significantly reduced the expression of alpha-SMA by LECs while TGF-beta and IGF-1 had no statistically significant effect. These results suggest that bFGF and EGF do not primarily induce secondary cataract formation by the mechanism of cell transdifferentiation.

Therapie der diabetischen Retinopathie mit Somatostatinanaloga

Somatostatin analogues are a therapeutic option in patients with chronic overproduction of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). These factors are also involved in the pathogenesis of diabetic retinopathy. Somatostatin receptors are expressed in the retina and are therefore possible targets of somatostatin analogues in the treatment of retinal vascular diseases like diabetic retinopathy. The somatostatin analogue octreotide has shown promise as a safe and effective treatment for advanced diabetic retinopathy and diabetic macular edema. The compound blocks the local and systemic production of GH and IGF-1, and thus inhibits the angiogenic effect. Evidence from animal models, and clinical trials in patients with diabetic retinopathy, suggest that octreotide can delay, and to some extent reverse diabetic retinopathy.

Octreotide prevents growth factor-induced proliferation of bovine retinal endothelial cells under hypoxia

Ocular diseases such as proliferative diabetic retinopathy are the major cause of blindness in industrialized countries. The main pathologic features of these diseases are hypoxia and overproduction of growth factors resulting in pathologic proliferation of endothelial cells and new vessel formation. Particularly, hypoxia and growth factors, such as VEGF, IGF-1, bFGF and TGF beta(2), show a complex interaction in the onset and progression of the diseases. Therefore, to date, most therapeutic strategies for proliferative retinopathies have targeted proliferation of endothelial cells evoked by growth factors. Recently, a synthetic analog of somatostatin, octreotide, has been shown to inhibit the proliferation of various cells in vitro, including endothelial cells. In this study, we have investigated the proliferative response of bovine retinal endothelial cells (BREC) to growth factors under hypoxic conditions and the modulation by octreotide. We found a dose-dependent increase of cell proliferation with VEGF, IGF-1 and bFGF, and inhibition of hypoxia-induced cell proliferation with TGF beta(2). Moreover, growth factor-induced, but not hypoxia-induced, cell proliferation was attenuated in the presence of octreotide. In contrast, TGF beta(2) abolished hypoxia-induced BREC proliferation. Similar to octreotide BIM23027, a somatastatin receptor subtype 2 (SSTR2) receptor agonist was able to attenuate the growth factor-induced proliferation of BREC expressing mRNA and protein for SSTR2. Therefore, we postulate that octreotide exerts its effects mainly through binding to the SSTR2. Taken together, our findings point to octreotide as a promising candidate for the treatment of eye disorders involving growth factor-dependent proliferation of endothelial cells.

[Diabetic retinopathy. Pathophysiology and therapy of hypoxia-induced inflammation]

Diabetic retinopathy is the most common chronic microvascular complication associated with diabetes mellitus. The development of diabetic retinopathy is a consequence of metabolic dysregulation. Hyperglycemia is a critical factor which is involved in basement membrane thickening, loss of pericytes and endothelial cells, and retinal capillary nonperfusion. We review the molecular basis of diabetic retinopathy and maculopathy and elaborate the role of growth factors and cytokines in the development of diabetic vascular alterations, their specific influence on the cellular interaction between retinal endothelial cells and pericytes, and the role of intravascular blood components.

[Intracanalicular trabeculostomy with the Er:YAG laser]

PURPOSE

To develop a new ab externo technique for glaucoma trabecular surgery using the infrared Er:YAG laser radiation (2.9 micrometer) guided into Schlemm's canal by an optical fiber.

MATERIAL AND METHODS

In order to create a drainage canal to the anterior chamber, a quartz fiber (core diameter: 100 micrometer) coupled to an Er:YAG laser was shielded by a metal canula (diameter: 280 micrometer) bent in conformance to the curvature of Schlemm's canal. A 45 degrees -mirror enabled the laser radiation to exit the canula perpendicular to the fiber axis. The complete surgery device was tested on agar medium and enucleated human eyes.

RESULTS

Using the unshielded quartz fiber, eight pulses of 8 mJ (frequency: 7 Hz, pulse duration: 150 microseconds) were sufficient to perforate the trabecular meshwork of the human eye. Histology showed a rippled canal with 50 micrometer average diameter and a surrounding necrosis zone of 15-35 micrometer. The complete device could be easily inserted into Schlemm's canal similar to the classic trabeculostomy probe and a conical-shaped canal with a length of 2-3 mm could be created in agar medium within a few seconds.

CONCLUSIONS

Initial experience in an experimental set-up show the ab externo creation of a draining canal between Schlemm's canal and the anterior chamber with only minimal irritation of the surrounding tissue. Further refinements of the laser parameters and the biomechanical set-up resulted in a new hand-held device with improved function. The Er:YAG laser intracanalicular trabeculostomy could become a new ab externo technique for minimal invasive therapy of open angle glaucoma.

[Objective determination of optical density of xanthophyll after supplementation of lutein]

BACKGROUND

It is thought that a high optical density of xanthophyll has a protective effect against the development of aggregated macular degeneration. The aim of this study was to investigate whether an increase of the optical density of xanthophyll in the macula after a supplementation of lutein can be proven by objective methods. Most methods applied for the determination of the macular pigment require the co-operation of the proband and the ability for foveal fixation.

METHOD

Imaging spectrometry and the evaluation of laser scanner images taken at 488 nm will be presented. In contrast to psychophysical methods, both methods are independent of the patients ability for foveal fixation.

RESULTS

Even by evaluation of laser scanner images taken as in fluorescence angiography but without inserting the blocking filter, the 2-dimensional distribution of xanthophyll can be determined. In 10 probands taking 6 mg lutein daily over 40 days, an increase of the optical density could be determined at least in some probands. The optical density reached a plateau 30 days after starting the supplementation of lutein.

CONCLUSION

The assumed protective effect of xanthophyll against age-related macular degeneration can be influenced by supplementation of lutein under objective control.

[Iris metastases in breast carcinoma]

BACKGROUND

Metastatic cancer of the iris is rare. We report a case of breast carcinoma which metastasized to the iris and a review of the literature.

METHOD

A 60-year-old woman with a history of breast carcinoma presented with lesions of the iris 5 years after diagnosis and tumor excision. In addition to slit-lamp examination including gonioscopy, ultrasound biomicroscopy, positron-emission tomography and fluorescein angiography of the iris were used for diagnosis. Furthermore, the literature was searched using the medline database.

RESULTS

The iris metastasis exhibited multiple whitish to pink nodules on the inferior half of the iris and infiltration of the chamber angle. The main tumor mass was prominent and highly vascularized. Best corrected visual acuity was 20/40 and the intraocular pressure was 7 mmHg. Ultrasound biomicroscopy showed lobular masses characterized by mid to low reflectivity and there was no distinct border to the surrounding tissue. Fluorescein angiography of the iris showed tumor vessels with dye leakage. The positron-emission tomography displayed metastatic lesions to the liver, lung, bones and lymph nodules in addition to the lesion of the iris. The review of the literature revealed that breast carcinoma leads to choroidal metastases in 5% of cases and iris metastases are even rarer. In twothirds of these cases the lesions form unilateral whitish to red clumps at the horizontal meridian and in the inferior quadrants of the iris. The preferred treatment is chemotherapy and/or radiation therapy.

CONCLUSIONS

Breast carcinoma is rarely associated with iris metastasis. Positron-emission tomography is a sensitive diagnostic tool to identify metastatic lesions and is a useful method for planning therapeutic approaches. Radiation therapy, argon laser treatment and block excision are therapeutic options with an isolated metastasis of the iris.

Thalidomide and prednisolone inhibit growth factor-induced human retinal pigment epithelium cell proliferation in vitro

Thalidomide and prednisolone were recently introduced as treatment modalities in age-related macular degeneration (AMD). Growth factor-induced activation of retinal pigment epithelial (RPE) cells is a crucial event in this disease. The purpose was to examine the effect of thalidomide and prednisolone on growth factor-preactivated RPE cells. Human RPE cells were stimulated with 10 ng/ml platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), or vascular endothelial growth factor (VEGF) for 24 h. Afterwards, thalidomide (50 microg/ml) or prednisolone (100 ng/ml) were added for 24 h. RPE cell proliferation was determined by [3H]-thymidine incorporation. PDGF and bFGF significantly stimulated human RPE cell proliferation (p < 0.005), the value for VEGF stimulation was not significant (p = 0.3). The effect of the growth factors was diminished after addition of thalidomide and prednisolone (p < 0.005). The current study shows that the inhibitory properties of thalidomide and prednisolone remain even after growth factor activation of the cells.

Value of positron emission tomography in the diagnosis of malignant ocular tumors

PURPOSE

To address the question whether positron emission tomography (PET) can identify malignant ocular tumors.

METHODS

In patients with ocular tumors, PET was performed using the incorporation of the glucose analogue (18)F-2-fluoro-2-deoxy-D-glucose. The diagnosis of the ocular lesions was based on conventional diagnostic procedures including histologic examination.

RESULTS

Nineteen patients with a mean age of 62.8 +/- 14.2 years were included in this study. Nine patients with a mean age of 62.9 +/- 13.1 years displayed the presence of a malignant tumor including metastatic lesions (4), malignant melanomas (4) and squamous cell carcinoma (1). Additionally, 10 patients with a mean age of 62.8 +/- 15.9 years with benign lesions were studied. There was a statistically significant difference (p = 0.012) in tumor height and tumor volume, but not in tumor diameter between benign and malignant lesions. The smallest PET positive lesion measured 7 x 3 mm. PET was positive in 7 out of 9 malignant lesions and negative in all 10 benign lesions, i.e. there was no false-positive and two false-negative results. The two false-negative tumors represented malignant melanomas of the choroid. Additionally, results of the PET examination were independent of tumor size.

CONCLUSION

PET seems to be of limited value for the diagnosis of malignant melanoma of the choroid, i.e. a negative result does not exclude a malignant process.

Octreotide reduces vitreous hemorrhage and loss of visual acuity risk in patients with high-risk proliferative diabetic retinopathy

OBJECTIVE

Growth hormone and insulin-like growth factor-I have been implicated as strong promoters of proliferative diabetic retinopathy. We studied reduction of bleeding and preservation of visual acuity by treatment with the long-acting somatostatin analogue, octreotide, in diabetic patients at an advanced stage of proliferative diabetic retinopathy.

RESEARCH DESIGN AND METHODS

Randomized trial in a University hospital setting. Reading ophthalmologists were masked for octreotide use, diabetologists were aware of that treatment. Nine patients received 100 microg tid octreotide (verum) subcutaneously for a maximum of 36 months. Nine diabetics served as controls, no placebo treatment was used. Episodes of vitreous hemorrhages were counted, measurement of visual acuity, estimation of neovascularization by stereoscopic fundus photography and fluorescein angiography were carried out.

RESULTS

After 3 years of treatment, the incidence of vitreous hemorrhages and the need for vitreoretinal surgery was significantly lower (log rank test p = 0.002) in the octreotide-treated patients. Visual acuity was preserved and significantly better in the octreotide treated group compared to controls (p = 0.05).

CONCLUSIONS

In diabetics with high-risk proliferative retinopathy after full scatter laser coagulation, octreotide reduced the number of vitreous hemorrhages, preserving visual acuity.

[Prospective randomized comparative study of frequency doubling perimetry vs standard automated perimetry in patients with glaucoma]

AIM

To compare frequency doubling perimetry (FDP) versus standard automated perimetry in glaucoma. To evaluate the reproducibility of both methods.

PATIENTS AND METHODS

All the patients were tested (full threshold test) twice with both FDP (N-30) and Humphrey Field Analyzer II model 750 (HFA) (30-2 procedures) in random sequence, within one day. The parameters mean deviation (MD), pattern standard deviation (PSD) and measured thresholds per quadrant and center areas were evaluated for FDP/HFA comparison in 45 glaucoma patients. The same parameters were used for testing the reproducibility of FDP (n = 46) and HFA (N = 39). Additionally, the center and each quadrant area were checked for any deviation in the total deviation probability plots. For statistical analysis Kappa coefficients and Bland/Altman plots were used.

RESULTS

An average MD (FDP vs HFA) of -7.3 +/- 5.8 dB vs -8.9 +/- 7.6 dB and PSD of 6.9 +/- 2.4 dB vs 6.5 +/- 3.6 dB were found. Kappa coefficients denote marginal accordance (kappa: 0.11-0.38) for area deviations. In a total of 225 areas HFA detected 191 deviations and FDP 165. HFA measured more negative deviation compared with FDP in the case of MD < -15 dB. The reproducibility was 0.98 (MD) and 0.92 (PSD) for FDP and 0.98 (MD) and 0.95 (PSD) for HFA (95% confidence interval).

CONCLUSIONS

There was great conformity between FDP and HFA in glaucoma patients. HFA detected more deviations in the total deviation probability plots than FDP. There was a high reproducibility of both methods. FDP is an appropriate tool for detecting visual field loss in glaucoma patients.

Changes of retinal capillary blood flow in age-related maculopathy

BACKGROUND

To investigate retinal capillary blood flow characteristics in patients with age-related maculopathy (ARM).

METHODS

Retinal capillary blood volume (VOL), blood flow (FLOW), and velocity (VEL) were measured in four macular sectors (I, II, III, IV) and in two areas beyond the temporal superior and inferior major vessel arcades (V and VI) in: 10 eyes with early ARM (drusen > or = 63 microns and/or atrophy of the retinal pigment epithelium, RPE, < 175 microns and/or proliferation of RPE), 13 with late ARM (exudative), 10 with late ARM (fibrotic), 14 normal eyes of 14 children of patients with ARM, and in 4 age- and sex-matched control groups using the Heidelberg retinal flowmeter (HRF). Statistical analysis was performed with the exact Wilcoxon test using an additional adjustment procedure by Bonferroni-Holm.

RESULTS

As compared to the control group, there was no significant change of VOL, FLOW, and VEL in patients with early ARM. In patients with late ARM (exudative), there was a significant higher FLOW in sectors I, II, and IV and a higher VOL and VEL in sectors III and IV. The group with late ARM (fibrotic) showed a reduction of VOL and FLOW in sectors I-IV and of VEL in sectors II and IV. In children of ARM patients, VOL, FLOW, and VEL of sectors I-VI did not differ from the control group.

CONCLUSION

HRF measurements in patients with ARM indicate an increased macular retinal capillary blood flow in patients with the exudative form of late ARM and a decreased macular perfusion in those with the fibrotic form.

[Dilatation of large retinal vessels after increased intraocular pressure]

PURPOSE

To measure dilation of large retinal branch vessels.

METHODS

Diameters of a vessel section of a branch artery and vein were examined by the retinal vessel analyzer. Intraocular pressure (IOP) was increased briefly by an oculo-oscillo-dynamograph. The examination was repeated after 2 weeks.

RESULTS

A vessel reaction was found in all volunteers. The mean venous diameter decreased 9.9 +/- 9.4% during the suprasystolic phase of intraocular pressure. A maximal dilation was found in arteries (7.0 +/- 6.2%) and veins (9.3 +/- 5.2%) 1 min after lowering of IOP. The results were reproduced in the second examination for veins in all phases of the examination and for arteries in the middle phase after lowering IOP (4 min). Various changes in mean systolic blood pressure did not significantly affect reproducibility of the vessel reaction.

CONCLUSION

The vessel reaction caused by rise in IOP can be measured for single vessel sections. The venous reaction is well reproducible in healthy volunteers. Further research should examine the benefit of this method in the diagnosis and follow-up of glaucoma.

[Effect of octreotide combined with growth factors on proliferation of RPE cells in vitro]

BACKGROUND

The long-acting somatostatin analogue octreotide is used as a therapeutic option for patients with diabetic retinopathy and age-related macular degeneration. Growth factors, such as EGF, bFGF, VEGF, and PDGF, have been implicated in the pathogenesis of these diseases. The aim of this study was to investigate the effect of octreotide on the growth-factor-induced proliferation of bovine retinal pigment epithelial (RPE) cells in vitro.

METHODS

RPE cells were assayed for proliferation as measured by (3H)-thymidine uptake (ccpm). Bovine RPE cells at passage 3-8 were seeded in a 96-well plate and incubated for a 24-h period with a minimum medium followed by a 24-h incubation with the different growth factors at a concentration of 10 ng/ml with and without 5 x 10(-5) M octreotide. In a different assay the cells were incubated with octreotide at 5 x 10(-10)-5 x 10(-4) M. Afterwards the cells were pulsed with 5 microCi/ml (3H)-thymidine for 12 h, and the incorporated radioactivity was measured on glass fiber filters in a beta-counter (mean +/- SEM ccpm). The Wilcoxon Signed Rank test and the student's t-test were used for statistical analyses.

RESULTS

There was a biphasic effect of octreotide on RPE cell proliferation. Exposure of RPE cells to PDGF (20,225 +/- 3304 ccpm) and bFGF (3441 +/- 539 ccpm) resulted in a significantly higher proliferation compared to control medium (1543 +/- 352 ccpm) (p < 0.05). No difference was found for EGF (2385 +/- 383 ccpm). For VEGF (776 +/- 83 ccpm) a significant reduction in RPE cell proliferation was found (P < 0.05). There was a significant reduction in proliferation of RPE cells with PDGF, bFGF, and EGF in combination with octreotide versus growth factors alone (octreotide in combination with PDGF 308 +/- 82 ccpm, with bFGF 229 +/- 88 ccpm, with EGF 2362 +/- 91 ccpm) (p < 0.005). VEGF in combination with octreotide resulted in a significant inhibition of RPE cell proliferation compared to VEGF alone (p < 0.0005).

CONCLUSION

The data suggest that there is an inhibitory effect of octreotide on RPE cell proliferation of bovine RPE cells and on the increased proliferation of bovine RPE cells induced by PDGF and bFGF. An enhanced inhibitory effect is found for the combination of octreotide and VEGF.