Verteporfin photodynamic therapy induced apoptosis in choroidal neovascular membranes

AIM

To evaluate the impact of verteporfin photodynamic therapy (PDT) on the induction of apoptosis in choroidal neovascular membranes (CNV) secondary to age related macular degeneration.

METHODS

Retrospective review of 22 surgically excised CNV. 12 of these patients had been treated with PDT 3-146 days previously. Apoptotic cells were detected with the TUNEL technique and compared to the expression of CD34 (endothelial cells, EC), CD105 (activated endothelial cells), Ki-67 (proliferation marker), and cytokeratin18 (retinal pigment epithelial cells, RPE).

RESULTS

CNV excised 3 days after PDT were characterised both by collapsed and patent vessels. The EC displayed a statistical significant positive TUNEL reaction when compared to the remaining treated CNV (p < 0.001) and untreated CNV (P = 0.002). The proliferative activity was reduced. CNV excised 1-5 months after PDT displayed a patent vascularisation and high proliferative activity. All membranes either treated or untreated disclosed only sporadic TUNEL positive cells within the stroma and the RPE.

CONCLUSIONS

Verteporfin PDT leads to selective and effective damage of EC within CNV. Both patent and occluded vessels were lined by apoptotic EC. This finding and the increased expression of proliferation marker at later time points suggest that revascularisation after PDT is caused by angiogenesis rather than recanalisation.

["Do you have a remedy for macular degeneration?" A field study about the advice given on dietary supplementation in 60 German pharmacies]

PURPOSE

Since completion of the AREDS study, evidence has accumulated to suggest that some form of dietary supplementation may be of value in special individuals who are at risk of progressive age-related macular degeneration (ARMD). We wanted to find out which of the many supplements available are recommended in practice and which instructions, promises, and purchasing arguments are used by German pharmacies.

METHODS

A blinded consultation following a standardized protocol was carried out in 60 pharmacies.

RESULTS

In 36 pharmacies specific products for dietary supplementation were recommended, but the dosage never complied with the AREDS study, and in 24 pharmacies, the necessity for a medical examination or consultation with an ophthalmologist was not mentioned. Possible interactions with other drugs or side effects were generally excluded.

CONCLUSIONS

Potential risks of supplement intake were underestimated. Medical knowledge of the most frequent cause of blindness in the Western world was insufficient. A clear policy of recommendations according to evidence-based criteria is needed.

Empfehlung für die Durchführung von intravitrealen Injektionen

The intravitreal injection as a minimally invasive intervention has proved to be an effective therapy in the management of numerous vitreoretinal diseases. However, non-standardized performance of the procedure might cause severe complications. The recommendations for intravitreal injections discussed here are intended to contribute to a minimization of the risk for complications. Of particular importance are a meticulous preoperative antisepsis with povidone iodine, a sterile environment using a sterile lid speculum, drape and gloves, the use of an adequate injection technique and the exclusion of postoperative retinal non-perfusion.

Histopathological analysis in experimental macular surgery with trypan blue

AIM

To analyse the effect of trypan blue on the retina in an experimental setting of macular surgery.

METHODS

Porcine eyes were used within 3 hours after death. The eyes were hemisected and the vitreous removed. Trypan blue (0.15%) was applied over the trephined posterior pole, whereas the rest of the eye cup was filled with a balanced salt solution (BSS). The dye and the BSS were removed after 1 minute and the complete eye cup irrigated and filled with fresh BSS. Both the treated and untreated retinas were illuminated with a standard surgical light pipe and source at maximum power for 10 minutes. Both the trypan blue exposed retina and the non-treated surrounding retina were processed for histology.

RESULTS

Exposure of the retina to trypan blue for 1 minute, followed by illumination caused no histologically detectable damage compared to the controls. No microarchitectural disorganisation, cellular disruption, or affection of the vitreoretinal interface was detected.

CONCLUSIONS

These findings indicate that a 1 minute exposure of trypan blue followed by illumination does not cause an acute morphologically detectable toxic effect on the porcine retina.

Augenverletzungen im Kindes- und Jugendalter

Childhood trauma of the eye and its adnexa represents approx. 4 - 20 % of all eye injuries. Due to ambiguous patient history and limited cooperation a comprehensive diagnosis of pediatric eye trauma is often difficult. The weakness of the infantile cornea, the thin and elastic anterior lens capsule, and the firm vitreous with its strong adherence to the retina bear particular intra- or postoperative problems. Moreover, the quick development of secondary cataract and the high risk of PVR may complicate the posttraumatic and postoperative course. Small infants represent a special subgroup in various regards mainly because of the risk of amblyopia which often causes functional loss in spite of a good anatomical reconstruction. The relative frequency of certain injuries differs between children and adults. The ocular manifestation of child abuse as well as bite and fireworks injuries are characteristic for childhood and will be discussed more in detail.

Vitrektomie mit oder ohne Cerclage in der Behandlung von Netzhautabl�sungen

In the beginning, pars plana vitrectomy was often combined with encircling elements in the treatment of complicated retinal detachments. Initial considerations were the limited control of the vitreous base due to the restricted view of the fundus periphery and the prevention of redetachment by anterior tears or traction. Today, additional encircling is justified in specified conditions of retinal surgery, e.g., retinal shortening by long-lasting detachments, anterior PVR, or choroidal injuries. Despite several synergistic effects in surgical management, severe complications have to be taken into account for scleral buckling in vitreoretinal surgery. Nevertheless, primary vitrectomy in combination with scleral buckling has led to a marked decrease of primary failure rate and improvement of functional results in retinal detachment surgery.

Reproducibility of circadian retinal and optic nerve head blood flow measurements by Heidelberg retina flowmetry

BACKGROUND/AIM

The Heidelberg retina flowmeter (HRF) is designed to measure retinal capillary blood flow. Previous studies however showed weak reproducibility of data. The intraindividual reproducibility of circadian HRF measurements was examined in healthy subjects in three locations of the retina.

METHODS

36 healthy volunteers (27.3 (SD 4.3) years) were examined by HRF seven times a day (t0-t6). Using a default window of 10 x 10 pixels, three consecutive measurements were performed in three precise focusing planes: superficial, intermediate and deep layer, peripapillary retina, neuroretinal rim and cup, respectively. Images of identical tissue locations identified by capillary landmarks of each layer were selected to quantify the retinal microcirculation of each volunteer. Means and standard deviations of all flow results of a given subject were calculated, at t0-t6 and the coefficients of variation as a measure of reproducibility.

RESULTS

The coefficients of variation ranged between 8.4% and 41.0% in the superficial layer (mean 19.8% (SD 8.4%)), 10.6%, and 43.0% in the intermediate layer (mean 24.0% (SD 8.4%)), and 9.9% and 84.0% (mean 29.6% (SD 15.8%)) in the deep layer.

CONCLUSIONS

These data show the best reproducibility of measurements in the superficial layer followed by the intermediate and the deep layer. Clinically, this is an unsatisfactory intraindividual reproducibility of flow values in each studied layer.

Clinicopathological findings of choroidal neovascularisation following verteporfin photodynamic therapy

AIMS

To report the clinicopathologic findings of surgically excised choroidal neovascularisation (CNV) three days after verteporfin photodynamic therapy (PDT).

METHODS

In three patients (three eyes) with age related macular degeneration, the CNV was surgically removed three days after PDT. The CNV specimens were examined by light microscopy.

RESULTS

The patients had subfoveal classic CNV. Fluorescein angiography revealed non-perfusion of the CNV after PDT and before surgery in all eyes. The light microscopy of the CNV membranes showed swollen and damaged endothelium. Thrombus formation or vascular occlusion in the CNV vessels was not detected.

CONCLUSION

PDT did not cause a thrombosis of the vessels within the CNV three days after PDT. Severe endothelial damage of the CNV was observed and is likely a primary effect of PDT. Non-perfusion of the CNV at this stage is possibly secondary to occlusion at a deeper level, namely the underlying feeding choroid.

Nebenwirkungen und Komplikationen der intravitrealen Triamcinolonacetonid-Therapie

With the advent of intravitreal triamcinolone acetonid injections major focus was assigned to potential ocular side effects. The current discussion is dominated by the potential cytotoxicity of particular biologically incompatible components. Those are regarded as substantial pathogenetic factor of the sterile pseudoendophthalmitis that seems to be avoidable by meticulous purification of the commercially available preparations. Even sustained subretinal or epiretinal deposits disclosed no signs of retinal toxicity. Major ocular side effects comprise temporary corticosteroid glaucoma and progressive cataract formation. Infectious endophthalmitis represents a rare but serious complication that might be set into critical context with hygienic surgical standards applied. Due to steroid-induced immune suppression clinical signs of inflammation might be masked and a proper diagnosis delayed. Other rare complications reported include a transient central retinal artery occlusion, conjunctival ulcerations, retinal detachment and potential reactivation of a cytomegalovirus retinitis. In conclusion, ocular side effects and complications show a wide variety of clinical signs and underlying causal mechanisms. However, the consequences are mostly temporary and show a good response to therapeutic intervention.

Variability of the normalised rim/disc area quotient estimated by laser scanning tomography. A comparison with conventional planimetry

BACKGROUND

The introduction of the laser scanning tomograph raises the possibility of the estimation of optic disc morphology in a less subjective and less time-consuming way than the conventional planimetry of fundus photography. The aim of the present study was to estimate the efficiency of the HRT method in a comparison of data collected in a glaucomatous patient group to planimetric data obtained in young normal volunteers.

METHODS

Repeated rim/disc area measurements were done in 10 glaucoma patients with a Heidelberg Retina Tomograph and in a group of five young volunteers with good vision. The intra-photographic, intra-observer examination of the planimetric method was compared to the inter-photographic assessment of the HRT technique.

RESULTS

The variability of the mean normalised area ratio quotient was nearly 50% less using laser scanning tomography techniques (mean rim/disc area ratio = 0.17).

CONCLUSION

The results show the superiority of HRT over the conventional planimetric technique. Furthermore, the much shorter processing time and the advantages of a computer-based databank in follow-up examination with HRT provides the hope that it could replace the rather time-consuming and subjective manual planimetric technique in the examination of glaucomatous optic nerve conditions.

Retinectomy for treatment of intractable glaucoma: long term results

AIM

To report long term efficacy and complications of retinectomy as an intraocular pressure lowering procedure for intractable glaucoma.

METHODS

This was a consecutive interventional case series. In 44 consecutive eyes (39 patients, 22 men and 17 women) retinectomy was performed to lower the intraocular pressure (IOP) in patients with uncontrolled IOP (>35 mm Hg for more than 4 months) despite conventional filtering surgery and drug treatment. Pars plana vitrectomy was performed and the peripheral retina was surgically excised to various degrees. The procedure was concluded by an intraocular gas tamponade of 20% C(3)F(8). Included were patients with neovascular glaucoma (12 eyes), infantile and juvenile glaucoma (three eyes), secondary glaucoma due to aphakia (13 eyes), severe ocular trauma (seven eyes), uveitis (seven eyes), and glaucoma in Ehlers-Danlos syndrome (two).

RESULTS

All patients underwent successful surgical retinectomy. All patients were followed for 5 years. Mean postoperative IOP after 4 years was 15.7 (SD 9.4) mm Hg, representing a decrease of IOP by 61% compared to the preoperative level (41.2 (9.4) mm Hg). In 52.3% of eyes long term regulation of IOP could be achieved without complications. Retinectomy was least effective in neovascular glaucoma because of central retinal vein occlusion (CRVO). Eyes with glaucoma secondary to uveitis showed a tendency towards low IOP levels with subsequent phthisis bulbi. The initial visual acuity of all patients was lower than 20/50 (mean 1.8 (0.8) logMAR) in the treated eye. Final visual acuity was 2.3 (0.6) logMAR. 21 out of 44 cases developed retinal complications (retinal detachment or proliferative vitreoretinopathy (PVR)) after surgery, requiring silicone tamponade in 11 eyes (52%) either for persistent low IOP or for PVR. Nine eyes developed phthisis, seven of which were enucleated during the follow up.

CONCLUSIONS

Long term results after retinectomy demonstrate its efficacy in otherwise intractable glaucoma. Efficacy and safety of retinectomy are dependent on the underlying disease.

Clinicopathological correlation of choroidal neovascularization after external beam radiotherapy in age-related macular degeneration

PURPOSE

To analyze the histopathology of choroidal neovascularization after external beam radiotherapy in age-related macular degeneration.

METHODS

A retrospective non-case-matched comparative histopathologic study. The histoarchitecture of nine surgically removed subretinal specimens from nine patients that had undergone external beam radiotherapy for exudative age-related macular degeneration was studied. Seven patients had received 20 Gy in 10 fractions and two 15 Gy in 5 fractions with an average time interval between radiotherapy and surgical extraction of 14 months (range 3-28). A consecutive series of classic, mixed and occult choroidal neovascular membranes served as controls.

RESULTS

Clinical findings. Radiation-associated choroidal neovasculopathy was angiographically suspected in four patients: a coarse net of vessels on fluorescein angiography developing at the border of previously irradiated choroidal neovascularization was observed in three patients; blebs at the margin of a plaque on indocyanine green angiography were observed in two patients. Pathological findings. Diffuse drusen as well as intra-Bruch's fibrovascular tissue was found in all irradiated specimens. In four specimens an edematous vascularized layer was seen between diffuse drusen and normal-appearing intra-Bruch's fibrovascular tissue. This lesion was not found in the control specimens. A particular correlation for the bleb lesion was not recognized.

CONCLUSION

The appearance of an edematous subretinal pigment epithelial vascularized layer between diffuse drusen and normal-appearing fibrovascular tissue in four of nine irradiated membranes may be secondary to previous irradiation. It may correlate with the unusual exudative manifestations observed after external beam radiotherapy.

Biocompatibility tests on the intraocular vision aid IOVA

Intraocular miniaturized image transmission systems are developed to restore vision in patients with irreversible destruction of the anterior ocular segment (i.e. chemical burns, explosion trauma, trachoma) and high risk for corneal transplantation, provided that the posterior ocular segment is intact. To ensure safety of such a device biocompatibility tests were conducted. In the present study the effects of light and temperature in various intensities and the toxicity of the implanted materials on neural function in the rabbit retina in-vivo was investigated. All tests give encouraging results concerning the feasibility of intraocular miniaturized image transmission systems.

Subretinally transplanted embryonic stem cells rescue photoreceptor cells from degeneration in the RCS rats

The Royal College of Surgeons (RCS) rat is an animal model for retinal degeneration such as the age-related macular degeneration. The RCS rat undergoes a progressive retinal degeneration during the early postnatal period. A potential treatment to prevent this retinal degeneration is the transplantation into the subretinal space of cells that would replace functions of the degenerating retinal pigment epithelium (RPE) cells or may form neurotrophic factors. In this study we have investigated the potential of subretinally transplanted embryonic stem cells to prevent the genetically determined photoreceptor cell degeneration in the RCS rat. Embryonic stem cells from the inner cell mass of the mouse blastocyst were allowed to differentiate to neural precursor cells in vitro and were then transplanted into the subretinal space of 20-day-old RCS rats. Transplanted and sham-operated rats were sacrificed 2 months following cell transplantation. The eyes were enucleated and photoreceptor degeneration was quantified by analyzing and determining the thickness of the outer nuclear layer by light and electron microscopy. In the eyes transplanted with embryonic cells up to 8 rows of photoreceptor cell nuclei were observed, whereas in nontreated control eyes the outer nuclear layer had degenerated completely. Transplantation of embryonic stem cells appears to delay photoreceptor cell degeneration in RCS rats.

Clinicopathologic correlation in hemorrhagic age-related macular degeneration

PURPOSE

To analyze and compare the histopathology of surgically extracted membranes in hemorrhagic age-related macular degeneration (AMD) versus extracted classic, mixed and occult choroidal neovascularization (CNV) in AMD.

METHODS

Thirty consecutive membranes, surgically removed in hemorrhagic AMD, were analyzed and compared with consecutive series of 50 classic, 20 mixed and 20 occult membrane specimens in exudative AMD. The specimens were serially sectioned and stained in a stepped fashion with hematoxylin-eosin, Masson trichrome and periodic acid-Schiff stain.

RESULTS

Diffuse drusen were observed in all hemorrhagic AMD specimens, fibrovascular tissue was found in 29 of 30 specimens which was located subretinally in 11 specimens and/or in Bruch's membrane in 28 specimens. A hemorrhage was located subretinally in 21 specimens, in the stroma of the fibrovascular tissue in 17 specimens, at the choroidal side of the diffuse drusen adjacent to fibrovascular tissue in 13 specimens and at the choroidal side of the fibrovascular tissue in Bruch's membrane in 8 specimens. Grossly dilated thin-walled vessels were identified in one hemorrhagic AMD case, suggestive of polypoidal choroidal vasculopathy. Scarred tears of the retinal pigment epithelium were identified in two specimens.

CONCLUSION

A large spectrum of histo-architectural lesions is recognized in hemorrhagic maculopathy. Hemorrhages do not only characteristically appear in the subretinal space or in the stroma of the neovascular tissue but also at the choroidal side of the diffuse drusen adjacent to the neovascular complex and at the choroidal side of the intra-Bruch's fibrovascular tissue.

[Visual prognosis and patient selection]

Choroidal neovascularization (CNV) is one of the leading causes of central vision loss. Laser photocoagulation and photodynamic therapy may reduce the risk of severe loss of visual acuity in subfoveal CNV secondary to age-related macular degeneration. However, the most favorable effect of these therapies is the slowing of the vision loss. Macular translocation surgery, removing the neurosensory retina away from the area of choroidal neovascularization to a healthier underlying tissue, may improve or stabilize the visual acuity. Several pilot studies of this surgery reported visual recovery in selected patients. Well-designed, controlled randomized studies are needed to clarify the role of the macular translocation surgery in treatment of choroidal neovascularization. Given the severe complications of this surgery, it is of utmost importance to discuss the potential risks and advantages of this procedure with the patient.