Retinal damage extends beyond the border of the detached retina in fovea-on retinal detachment

PURPOSE

The aim of this study was to investigate the preoperative and postoperative change in retinal sensitivity in relation to the distance to the retinal detachment (RD) in patients with fovea-on RD.

METHODS

We prospectively evaluated 13 patients with fovea-on RD and a healthy control eye. Preoperatively, OCT scans of the RD border and the macula were obtained. The RD border was highlighted on the SLO image. Microperimetry was used to assess the retinal sensitivity at the macula, the RD border and the retina around the RD border. At 6 weeks, 3 and 6 months postoperatively, follow-up examinations of OCT and microperimetry were performed in the study eye. Microperimetry was performed once in control eyes. Microperimetry data were overlaid on the SLO image. The shortest distance to the RD border was calculated for each sensitivity measurement. The change in retinal sensitivity was calculated as control-study. The relation between the change in retinal sensitivity and the distance to the RD border was assessed using a locally weighted scatterplot smoothing curve.

RESULTS

Preoperatively, the greatest loss in retinal sensitivity was 21 dB at 3° inside the RD which decreased linearly, through the RD border, and reached a plateau of 2 dB at 4°. For 6 weeks and 3 months postoperatively, the greatest retinal sensitivity loss remained at 3° inside the RD but was 4 dB and sensitivity loss decreased linearly to a plateau of 0 dB at 5° outside the RD. At 6 months postoperatively, the greatest sensitivity loss was 2 dB at 3° inside the RD, and decreased linearly to a plateau of 0 dB at 2° outside the RD.

CONCLUSIONS

Retinal damage extends beyond the detached retina. Retinal sensitivity loss of the attached retina decreased drastically as the distance to the RD increased. Postoperative recovery occurred for both attached and detached retina.

Prevalence of vitreoschisis-induced vitreous cortex remnants over the peripheral retinal surface in eyes undergoing vitrectomy for primary rhegmatogenous retinal detachment

PURPOSE

Unremoved vitreoschisis-induced vitreous cortex remnants over the peripheral retinal surface posterior to the vitreous base (pVCR) may increase the risk of surgical failure after primary rhegmatogenous retinal detachment (RRD) repair. The purpose of this study was to validate our previous findings on pVCR prevalence during vitrectomy for RRD and to examine their association with proliferative vitreoretinopathy (PVR) and surgical failure.

METHODS

Prospective observational multisurgeon study of 100 eyes of 100 consecutive patients who underwent vitrectomy for RRD by one of four vitreoretinal surgeons. Collected data included detected pVCR and known PVR risk factors. Pooled analysis with our previous retrospective study (251 eyes of 251 patients) was also performed.

RESULTS

Initial PVR (≥C) was present and removed in 6/100 (6%) patients, pVCR were detected in 36/100 (36%) patients, pVCR were removed in 30/36 (83%) patients with pVCR, and 4/36 (11%) patients with pVCR were high myopes (≤-6D). Six per cent (6/100) developed a retinal redetachment, of which 3/6 (50%) had initial PVR (≥C). Surgical failure rates in eyes with and without pVCR were 17% (6/36) and 0% (0/64), respectively. In eyes with pVCR and surgical failure, pVCR were not or not completely removed during the first surgery. Overall analysis showed that pVCR were statistically significantly associated with PVR.

CONCLUSIONS

This study confirms our previous findings: a pVCR prevalence of around 35% and an association between pVCR, PVR formation and surgical failure in patients undergoing vitrectomy for RRD. More research is needed to determine which patients would benefit most from pVCR removal.

Destructive inflammatory reaction after an autologous retinal pigment epithelium and choroid transplantation: no detection of an auto-immune response

Purpose

Five patients who underwent uncomplicated retinal pigment epithelium (RPE)-choroid transplantation for neovascular age-related macular degeneration developed a destructive inflammatory reaction causing subretinal fluid accumulation and extensive RPE atrophy in the graft. We hypothesized that this inflammation could be caused by an auto-immune response against the graft, resulting in circulating auto-antibodies. The aim of our study was to examine a potential autoimmune origin, which would allow a more targeted therapy approach.

Methods

Five above-mentioned patients and four control groups of five patients each were included: 1) after uncomplicated RPE-choroid transplantation, 2) after full macular translocation, 3) treated with anti-vascular endothelial growth factor, and 4) healthy controls. Histopathology of rejected graft tissue was performed using standard procedures. Presence of RPE-choroid autoantibodies in serum was examined by indirect immunofluorescence and Western blot, and human leukocyte antigen (HLA) typing was performed.

Results

Histopathological examination of an explanted graft showed infiltration of T-lymphocytes and macrophages in the choroid and RPE, and an increased number of B-cell lymphocytes were found in the choroid. Indirect immunofluorescence showed weak RPE-choroid autoantibody immunoreactivity in three patients of different groups. Western blot did not show specific RPE-choroid autoantibody immunoreactivity and no difference of HLA genotypes between the groups was found.

Conclusions

Although local mononuclear inflammatory cell infiltration and a high number of B-lymphocytes were observed in an explanted graft, we did not detect serological evidence of an autoimmune origin of the postoperative inflammation using direct immunofluorescence and Western Blot. Alternatively, the graft failure may have been caused by local innate inflammation, triggered by breakdown of tolerance. Based on our current findings of this small study group, we have no rationale to pursue therapies targeted towards autoreactive graft failure. More research is needed to confirm our findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12348-022-00305-2.

Validation of a multi-species-specific PCR panel to diagnose patients with suspected postoperative bacterial endophthalmitis

INTRODUCTION

Currently, patients suspected of endophthalmitis are referred to a tertiary centre for a vitreous biopsy and bacterial culture, thereby causing a treatment delay for the intravitreal antibiotics injection. We developed a new diagnostic tool, multi-mono-PCR (mm-PCR), not requiring viable bacteria, allowing antibiotic injection without delay. Performance of mm-PCR was tested on biopsies from patients with suspected postoperative endophthalmitis with known bacterial culture results.

METHODS

Most frequently occurring pathogens in endophthalmitis were determined using published data and treatment logs of endophthalmitis patient of the Rotterdam Eye Hospital. Vitreous biopsies from patients with suspected endophthalmitis were aliquoted in two parts. One part was sent out for bacterial culture and another was stored at -80°C for mm-PCR analysis and, as a backup, also by panbacterial PCR. Twelve vitreous samples from patients not suspected of having endophthalmitis were added as control samples.

RESULTS

Concordancy between bacterial culture and mm-PCR was 89% (24 of 27). All twelve control samples were negative. In three nonconcordant samples, the PCR results were most likely the correct ones.

CONCLUSION

mm-PCR results are highly concordant with bacterial culture. mm-PCR with panbacterial PCR as backup could be considered a diagnostic tool in patients with endophthalmitis, which would allow us to reverse the order of diagnosis and treatment while maintaining diagnostic surveillance, thereby preventing treatment delay.

Vitrectomy, subretinal Tissue plasminogen activator and Intravitreal Gas for submacular haemorrhage secondary to Exudative Age-Related macular degeneration (TIGER): study protocol for a phase 3, pan-European, two-group, non-commercial, active-control, observer-masked, superiority, randomised controlled surgical trial

Background

Neovascular (wet) age-related macular degeneration (AMD) can be associated with large submacular haemorrhage (SMH). The natural history of SMH is very poor, with typically marked and permanent loss of central vision in the affected eye. Practice surveys indicate varied management approaches including observation, intravitreal anti-vascular endothelial growth factor therapy, intravitreal gas to pneumatically displace SMH, intravitreal alteplase (tissue plasminogen activator, TPA) to dissolve the clot, subretinal TPA via vitrectomy, and varying combinations thereof. No large, published, randomised controlled trials have compared these management options.

Methods

TIGER is a phase 3, pan-European, two-group, active-control, observer-masked, superiority, randomised controlled surgical trial. Eligible participants have large, fovea-involving SMH of no more than 15 days duration due to treatment-naïve or previously treated neovascular AMD, including idiopathic polypoidal choroidal vasculopathy and retinal angiomatous proliferation. A total of 210 participants are randomised in a 1:1 ratio to pars plana vitrectomy, off-label subretinal TPA up to 25 μg in 0.25 ml, intravitreal 20% sulfahexafluoride gas and intravitreal aflibercept, or intravitreal aflibercept monotherapy. Aflibercept 2 mg is administered to both groups monthly for 3 doses, then 2-monthly to month 12. The primary efficacy outcome is the proportion of participants with best-corrected visual acuity (BCVA) gain of ≥ 10 Early Treatment Diabetic Retinopathy (ETDRS) letters in the study eye at month 12. Secondary efficacy outcomes (at 6 and 12 months unless noted otherwise) are proportion of participants with a BCVA gain of ≥ 10 ETDRS letters at 6 months, mean ETDRS BCVA, Radner maximum reading speed, National Eye Institute 25-item Visual Function Questionnaire composite score, EQ-5D-5L with vision bolt-on score, Short Warwick and Edinburgh Mental Wellbeing score, scotoma size on Humphrey field analyser, and presence/absence of subfoveal fibrosis and/or atrophy and area of fibrosis/atrophy using independent reading centre multimodal image analysis (12 months only). Key safety outcomes are adverse events, serious adverse events, and important medical events, coded using the Medical Dictionary for Regulatory Activities Preferred Terms.

Discussion

The best management of SMH is unknown. TIGER aims to establish if the benefits of SMH surgery outweigh the risks, relative to aflibercept monotherapy.

Trial registration

ClinicalTrials.govNCT04663750; EudraCT: 2020-004917-10.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05966-3.

Visual Acuity Inadequately Reflects Vision-Related Quality of Life in Patients After Macula-Off Retinal Detachment Surgery

Purpose

To determine the impact of postoperative visual function on the vision-related quality of life (VRQoL) in patients after anatomically successful surgery for macula-off rhegmatogenous retinal detachment (RRD) and to propose a classification to grade the extent of macular detachment using preoperative optical coherence tomography (OCT) scans.

Methods

This prospective study evaluated 48 patients. At 12 months after surgery, visual function assessments were as follows: metamorphopsia (M-CHARTS), aniseikonia (New Aniseikonia Test), best corrected visual acuity (BCVA) (Early Treatment Diabetic Retinopathy Study [ETDRS]), low contrast BCVA (10% ETDRS), color vision (Hardy Rand Rittler), and stereopsis (Titmus Fly). VRQoL was assessed by the National Eye Institute Visual Functioning Questionnaire-25 (NEIVFQ-25). Associations between visual function parameters and NEIVFQ-25 scores were evaluated. Preoperative OCT-scans were classified into six stages according to the extent of macular detachment based on an ETDRS-grid: incomplete perifoveal detachment (1), incomplete parafoveal detachment (2), incomplete foveal detachment (3), complete foveal detachment (4), complete parafoveal detachment (5), and complete perifoveal detachment (6).

Results

General vision and driving were the lowest scoring categories. General vision had the strongest correlation with low contrast BCVA (r = −0.41, P = 0.002), while driving had the strongest correlation with stereopsis (r = −0.39, P = 0.008). All macular detachments were graded stage 3 or beyond. Patients with stage 3 macular detachments had the highest visual function values compared to the other stages. The highest percentage of patients with metamorphopsia, aniseikonia and BCVA>0.1 logMAR was found in stages 5 and 6.

Conclusions

Macula-off RRD particularly affects general vision and driving. The extent of macular detachment is a potential predictor for visual function and can be graded using the proposed classification.

Smaller Foveal Avascular Zone in Deep Capillary Plexus Is Associated with Better Visual Acuity in Patients after Macula-off Retinal Detachment Surgery

Purpose

To associate the change in the foveal avascular zone (FAZ) and vessel density (VD) with final best corrected visual acuity (BCVA) in eyes after macula-off rhegmatogenous retinal detachment surgery, and to investigate the evolution of FAZ and VD during 12 months of follow-up.

Methods

We prospectively evaluated 47 patients with macula-off rhegmatogenous retinal detachment and healthy fellow eyes. At 1.5, 3.0, 6.0, and 12.0 months postoperatively, optical coherence tomography angiography scans were obtained from both eyes on a 3.0 × 3.0 mm macula-centered grid. En face images of the superficial vascular plexus, intermediate capillary plexus and deep capillary plexus were used to quantify FAZ and VD. BCVA was assessed with ETDRS-charts (logarithm of the minimal angle of resolution).

At 12 months postoperatively, the association between the change in optical coherence tomography angiography parameters and visual function in study eyes was evaluated using the Spearman correlation coefficient. We calculated the BCVA difference and the percentage difference of FAZ and VD between the study and control eye. The evolution of FAZ and VD was investigated with linear mixed-effects models with nested random effects (eyes nested within patients).

Results

At 12 months postoperatively, FAZ difference of the deep capillary plexus and BCVA difference were correlated (P = 0.0004, r_s = 0.5). Furthermore, there was no evidence that FAZ and VD changed during follow-up.

Conclusions

Although FAZ and VD remained stable during 12 months after surgery for macula-off rhegmatogenous retinal detachment, a smaller FAZ in the deep capillary plexus is associated with better BCVA.

Translational relevance

Reduction in FAZ area may be caused by angiogenesis to counteract ischemia, therefore therapeutic stimulation of angiogenesis could be beneficial to visual recovery.

The Influence of Prolongation of Interruptions of Preoperative Posturing and Other Clinical Factors on the Progress of Macula-On Retinal Detachment

PURPOSE

To evaluate whether prolongation of interruptions of preoperative posturing by sitting upright influences retinal detachment (RD) progression. The secondary objective was to find clinical factors to identify patients with a high risk for RD progression.

DESIGN

Prospective cohort study.

PARTICIPANTS

One hundred ninety-eight patients divided among 3 cohorts of patients with macula-on RD were included. Inclusion criteria were volume OCT scans of sufficient quality and smallest distance from the fovea to the detachment border of at least 1.25 mm. In the second and third cohort, 50 patients with only superior temporal RD were included.

METHODS

Patients were admitted to the ward in anticipation of surgery. Preoperative bed rest and positioning were prescribed. The position of the RD border was determined based on OCT imaging performed at baseline, before and after the usual interruptions for meals or toilet visits. The duration of interruptions was prolonged with sitting upright for 20 minutes in cohort 2 and for 40 minutes in cohort 3. Various secondary outcome measures were defined, such as the baseline area of subretinal fluid (SRF) as measured on ultrasound images in the third cohort.

MAIN OUTCOME MEASURES

The RD border displacement was determined. The worst RD progression from baseline was given by the shortest distance to the fovea in any of the OCT scans during follow-up. The worst relative RD progression from baseline was defined as the worst RD progression from baseline as a percentage of the baseline distance between RD border and fovea.

RESULTS

The median duration of interruptions was 22, 41, and 58 minutes in cohorts 1, 2, and 3, respectively. The median RD border displacement during interruptions in patients with superior temporal RD was not significantly different among the cohorts (P = 0.28). The correlation coefficient between the SRF area at baseline and worst relative RD progression from baseline was 0.37 (95% confidence interval, 0.04-0.66; P = 0.009).

CONCLUSIONS

We did not find a significant increase in RD progression after prolongation of interruptions by sitting upright. Patients with a larger area of SRF on ultrasound showed more RD progression from baseline.

Dabigatran inhibits intravitreal thrombin activity

PURPOSE

Proliferative vitreoretinopathy (PVR) is a vitreoretinal disorder in which retinal pigment epithelial (RPE) cell activation contributes to both formation of fibrotic retinal membranes and inflammation. Vitreous of patients with PVR contains increased thrombin activity which induces profibrotic and proinflammatory programs in RPE cells. Inhibition of intravitreal thrombin activity may thus represent a therapeutic option for PVR. In this study, we examined the capacity of the clinically available direct thrombin inhibitor dabigatran to inhibit thrombin activity in vitreous fluids.

METHODS

ARPE-19 cells were cultured with the following: (i) thrombin, (ii) vitreous without thrombin activity and (iii) vitreous with elevated thrombin activity (PVR samples and thrombin spiked vitreous) either in the presence or absence of dabigatran (range: 10^-5 to 10^-7  M). Subsequently, CCL2, CXCL8, GMCSF, IL6 and PDGFB mRNA expression levels were determined by RQ-PCR and protein levels of 27 cytokines, chemokines and growth factors were detected in culture supernatants using a multiplex approach. In addition, the capacity of vitreous fluids obtained from patients after oral dabigatran intake was tested in an in vitro thrombin activity assay.

RESULTS

Thrombin and vitreous fluids containing thrombin activity induced CCL2, CXCL8, GM-CSF, IL-6 and PDGF-BB expression by ARPE-19 cells, which was inhibited by dabigatran. In addition, dabigatran that reached the vitreous after repeated oral intake did inhibit thrombin activity in the in vitro activity assay.

CONCLUSION

Proliferative vitreoretinopathy (PVR) is associated with increased intravitreal thrombin activity that activates profibrotic and proinflammatory pathways in RPE cells. Our findings provide evidence that this activation pathway can potentially be inhibited by dabigatran.

A prospective multicentre randomized placebo-controlled superiority trial in patients with suspected bacterial endophthalmitis after cataract surgery on the adjuvant use of intravitreal dexamethasone to intravitreal antibiotics

PURPOSE

We aimed to determine whether intravitreal dexamethasone as an adjuvant to intravitreal antibiotics is beneficial in the treatment of suspected bacterial endophthalmitis after cataract surgery.

METHODS

Randomized, placebo-controlled superiority trial in three tertiary referral centres in the Netherlands. Patients with suspected bacterial endophthalmitis within 6 weeks after cataract surgery were eligible. A diagnostic vitreous biopsy was taken for culture, and patients received intravitreal injections of 400 μg dexamethasone (without preservatives) or placebo, in addition to 0.2 mg vancomycin and 0.05 mg gentamicin. The vancomycin and dexamethasone or placebo injections were repeated once at day 3 or 4. Primary outcome measure was best-corrected visual acuity (BCVA) at 1 year.

RESULTS

Between 1 November 2004 and 1 March 2014 (excluding two interruptions totalling 20 months), 324 eligible patients presented. A total of 167 patients (81 dexamethasone, 86 placebo) were available for the intention-to-treat analysis. Biopsies of 114 patients (68%) were culture-positive. Final BCVA did not differ between the dexamethasone and the placebo group (logMAR 0.31 ± 0.58 versus 0.27 ± 0.50; p = 0.90), nor did the number of patients with final vision of no light perception (LP, 7 versus 13). Pain, corneal oedema, the absence of a red fundus reflex on presentation, LP on presentation and culture of virulent pathogens from biopsy were statistically significantly associated with an unfavourable visual outcome.

CONCLUSION

Intravitreal dexamethasone without preservatives as an adjuvant to intravitreal antibiotics does not improve visual acuity (VA) in patients treated for suspected bacterial endophthalmitis after cataract surgery.

Thrombin Generation in Vitreous and Subretinal Fluid of Patients with Retinal Detachment

PURPOSE

To measure prothrombin fragments (F1+2) and thrombin-antithrombin complex (TAT) in vitreous and subretinal fluid (SRF) of rhegmatogenous retinal detachment (RRD) patients and to validate and further specify our earlier finding of increased thrombin activity in patients with proliferative vitreoretinopathy (PVR).

METHODS

F1+2 and TAT were measured in 31 vitreous and 16 SRF samples using the Enzygnost® immunoassays.

RESULTS

We found significant levels of F1+2 and TAT in the vitreous of all patients with RRD compared to patients with macular hole or macular pucker. However, there was no significant difference between patients who would develop PVR in the future, had established PVR, and patients with uncomplicated RRD both in vitreous concentrations of F1+2 (Kruskal-Wallis p = 0.963) and TAT (p = 0.516).

CONCLUSION

The analysis of F1+2 and TAT confirmed significant thrombin generation in both vitreous and SRF of patients with RRD. An imbalance between the thrombin regulation mechanisms TAT and α2-macroglobulin possibly explains the difference from our previous findings.

Postoperative aqueous humour flare as a surrogate marker for proliferative vitreoretinopathy development

PURPOSE

As some surgical procedures have been shown to increase postoperative flare values and thus contribute to blood-ocular barrier breakdown, retinal reattachment surgery might influence the risk of developing proliferative vitreoretinopathy (PVR). Therefore, we investigated whether postoperative aqueous flare values are a surrogate marker for the development of postoperative PVR.

METHODS

We prospectively included 195 patients with primary rhegmatogenous retinal detachment (RRD) and measured aqueous laser flare preoperatively, and at 2 and 6 weeks postoperatively. Postoperative PVR was defined as reoperation for redetachment due to PVR membranes, within 6 months of initial surgery. Logistic regression and receiver operating characteristic (ROC) analysis determined whether higher postoperative flare values were associated with an increased risk of developing PVR later on.

RESULTS

Reoperation for postoperative PVR was needed in 12 (6.2%) patients; in 18 (9.2%), reoperation was not related to PVR. The median flare value for patients who would develop PVR was significantly higher than that of patients who would not develop PVR, both at 2 weeks (p = 0.001) and 6 weeks (p < 0.001) postoperatively. Logistic regression analyses showed that a higher flare value significantly increased the odds of developing PVR, either at 2 weeks [odds ratio (OR) 1.027; 95% CI: 1.010-1.044] or 6 weeks (OR 1.076; 95% CI: 1.038-1.115).

CONCLUSION

Flare values both at 2 and 6 weeks postoperatively seem a good surrogate marker in terms of sensitivity and specificity for the development of postoperative PVR but have only a modest positive predictive value. The 2-week value would be more useful in terms of early recognition of high-risk patients and hence give the possibility to better study effects of treatment methods.

Visual acuity of 20/32, 13.5 years after a retinal pigment epithelium and choroid graft transplantation

Purpose

To present the 13.5-year-survival of an autologous retinal pigment epithelium (RPE) and choroid graft transplantation with good visual acuity results.

Observations

A 72-year old patient presented with a 5-weeks-old visual acuity deterioration to excentric finger counting at half a meter. Fundoscopy showed a fibrotic macular scar, a large subretinal hemorrhage, partly recent, combined with intraretinal fluid, blood, and hard exudates. RPE-choroid graft surgery was performed, and visual acuity improved to 20/32, and maintained up until 13.5 years postoperative. Microperimetry performed at the same time revealed a 3.4 dB sensitivity, with fixation on the graft. During the postoperative years glaucoma developed, an uveitis anterior was treated, and to treat a small Coats' like lesion; one bevacizumab injection was administered.

Conclusions and importance

A best corrected visual acuity of 20/32 could be achieved and maintained up to 13.5 years after an RPE-choroid graft transplantation, despite an unfavorable preoperative presentation and some early and late complications. This case is a proof of principle that an RPE-choroid graft harvested from the midperiphery can support the macular metabolism up to 13.5 after surgery in a patient with severe exudative AMD. It also represents a rationale for pursuing stem cell derived RPE replacement. Anti-vascular endothelial growth factor injections are nowadays the mainstay of therapy for choroidal neovascularization and/or small hemorrhages and offer good results. Nevertheless, selected patients that cannot benefit from this therapy may profit from an autologous RPE-choroid graft transplantation.

Preoperative aqueous humour flare values do not predict proliferative vitreoretinopathy in patients with rhegmatogenous retinal detachment

BACKGROUND/AIMS

Patients with rhegmatogenous retinal detachment (RRD) who develop postoperative proliferative vitreoretinopathy (PVR) have been found to have higher preoperative laser flare values than patients with RRD who do not develop this complication. Measurement of laser flare has therefore been proposed as an objective, rapid and non-invasive method for identifying high-risk patients. The purpose of our study was to validate the use of preoperative flare values as a predictor of PVR risk in two additional patient cohorts, and to confirm the sensitivity and specificity of this method for identifying high-risk patients.

METHODS

We combined data from two independent prospective studies: centre 1 (120 patients) and centre 2 (194 patients). Preoperative aqueous humour flare was measured with a Kowa FM-500 Laser Flare Meter. PVR was defined as redetachment due to the formation of traction membranes that required reoperation within 6 months of initial surgery. Logistic regression and receiver operating characteristic analysis determined whether higher preoperative flare values were associated with an increased risk of postoperative PVR.

RESULTS

PVR redetachment developed in 21/314 patients (6.7%). Median flare values differed significantly between centres, therefore analyses were done separately. Logistic regression showed a small but statistically significant increase in odds with increasing flare only for centre 2 (OR 1.014; p=0.005). Areas under the receiver operating characteristic showed low sensitivity and specificity: centre 1, 0.634 (95% CI 0.440 to 0.829) and centre 2, 0.731 (95% CI 0.598 to 0.865).

CONCLUSIONS

Preoperative laser flare measurements are inaccurate in discriminating between those patients with RRD at high and low risk of developing PVR.

Vitreous and subretinal fluid concentrations of orally administered dabigatran in patients with rhegmatogenous retinal detachment

PURPOSE

One of the factors that was shown to contribute to the development of proliferative vitreoretinopathy (PVR) is the coagulation factor thrombin. Therefore, a specific oral thrombin inhibitor such as dabigatran might be a possible therapeutic option. An oral drug has the advantage of patient-friendly prolonged administration in contrast to drugs that can only be applied during vitrectomy, on condition that the drug reaches the target site. We tested whether dabigatran reaches the vitreous and subretinal fluid (SRF) after a single oral dose of dabigatran.

METHODS

Twenty-eight patients with a retinal detachment received a single dose of 220 mg dabigatran etexilate 2-8 hr prior to surgery. During surgery, we took a blood sample and a vitreous or subretinal fluid sample. The concentration of dabigatran was measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

The dabigatran concentration between 2 and 9 hr after administration was higher in SRF than in vitreous (max 8.5 and 3.8 ng/ml). Corresponding plasma concentrations ranged from 15 to 225 ng/ml. There was a significant relationship between SRF levels and plasma levels (r_s  = 0.68, p = 0.014); the levels in vitreous fluid showed no such relationship (r_s  = 0.20, p = 0.48). In addition, we measured the vitreous concentration of a non-study patient using 150 mg dabigatran twice daily. The concentration was approximately 10 times higher than after a single dosage (25.8 ng/ml).

CONCLUSION

We demonstrate that oral intake of dabigatran, a candidate drug to modulate PVR, results in potentially relevant intraocular concentrations. We suggest that repeated dosing may lead to higher concentrations, but this should be further explored.

What made you wait so long? Delays in presentation of retinal detachment: knowledge is related to an attached macula

PURPOSE

In rhegmatogenous retinal detachment, the time between first symptoms and reattachment surgery is critical to prevent macular detachment. We explored which determinants discriminate between 'macula-ON' and 'macula-OFF' retinal detachments to improve timely treatment.

METHODS

Eight-hundred patients with rhegmatogenous retinal detachment admitted for surgery at the Rotterdam Eye Hospital in the Netherlands were eligible to complete a questionnaire to explore the following determinants: (i) patient's delay and doctor's delay; (ii) patient-reported causes for delay; (iii) symptoms as early warning signals; (iv) patient's prior knowledge about retinal detachment; and (v) trait anxiety.

RESULTS

Five hundred and twenty-one questionnaires (65%) were analysed. Median interval between first symptoms and surgery was 14 days. Macula-ON/OFF ratio was 46/54. Patient's delay in macula-ON patients (median 3 days) was shorter than in macula-OFF (5 days, p = 0.026). No difference was found in doctor's delay except for 'waiting time for surgery': macula-ON patients were operated on faster (median 1 day) than macula-OFF (median 5 days, p < 0.001). Macula-ON patients more often attributed symptoms to retinal problems. Except floaters, no symptoms were determined as early warning signals for macula-ON. Macula-ON patients more often reported knowing that prognosis would be worse when treated later, even when controlled for previous experience with retinal detachment.

CONCLUSION

Macula-ON patients seem to self-refer faster to a healthcare provider, seem more sensitive to floaters and seem more informed. This suggests that increasing awareness, especially about floaters, might increase the proportion of patients with macula still on at the moment of referral to the ophthalmologist.

Prospective, Randomized Intervention Study Comparing Retinal Pigment Epithelium-Choroid Graft Surgery and Anti-VEGF Therapy in Patients with Exudative Age-Related Macular Degeneration

Purpose: To investigate whether patients with exudative age-related macular degeneration and a submacular hemorrhage, retinal pigment epithelium (RPE) tear or nonresponders to anti-vascular endothelial growth factor (VEGF) benefit more from a free RPE-choroid graft transplantation surgery than from (continuation of) anti-VEGF treatment. Procedures: A total of 20 patients were included in this prospective, international, multicenter, randomized intervention study. Results: The change in the mean number of Early Treatment of Diabetic Retinopathy Study (ETDRS) letters in the graft group 1 year postoperatively was -15 (range -54 to +26), whilst 2 patients experienced a gain of >10 letters. The median preoperative visual acuity (VA) was 0.75 logMAR (range 0.46-2.8), and the mean postoperative VA was 1.48 logMAR (range 0.14-2.8). The change in the mean number of ETDRS letters in the anti-VEGF group was -8 (range -26 to +6); no patients experienced a >10 letter gain. The median preoperative VA was 1.36 logMAR (range 0.58-1.6), and the median postoperative VA was 1.42 logMAR (range 0.44-1.66). Conclusions: The included patient group is far too small to draw conclusions. However, both gain and loss of VA may be experienced by patients undergoing either treatment method; more gain might be possible for patients with a graft in the absence of complications.

Direct Blood Flow Measurements in a Free RPE-Choroid Graft with Phase-Resolved Doppler OCT

PURPOSE

We directly demonstrated the revascularization in a free retinal pigment epithelium (RPE)-choroid graft with direct blood flow detection by experimental phase-resolved Doppler optical coherence tomography (PRD-OCT).

METHODS

Seven patients with age-related macular degeneration underwent an RPE-choroid graft translocation in a prospective institutional cohort study. Spectral domain optical coherence tomography (SD-OCT) was used to measure the revascularization stage. With PRD-OCT the presence of flow was imaged postoperatively.

RESULTS

The PRD-OCT confirmed flow in three patients when SD-OCT indicated the afferent vessel ingrowth stage, and in all seven patients when the SD-OCT indicated the efferent vessel ingrowth stage.

CONCLUSIONS

The PRD-OCT study was able to detect the presence of blood flow in a free RPE-choroid graft. The PRD-OCT findings directly confirmed the revascularization that was otherwise based on the more circumstantial evidence provided by SD-OCT images and angiography.

TRANSLATIONAL RELEVANCE

The use of both techniques to monitor the revascularization process in a free graft in patients are an interesting example of replacing more invasive by noninvasive techniques. There is potential future use of PRD-OCT for the visualization of vascularization patterns in other pathologies.

A prospective multicenter randomized placebo-controlled trial of dexamethasone as an adjuvant in the treatment of postoperative bacterial endophthalmitis: interim safety analysis of the study drug and analysis of overall treatment results

PURPOSE

In an ongoing prospective multicenter randomised placebo-controlled trial we study the adjuvant use of intravitreal dexamethasone in the treatment of patients with suspected bacterial endophthalmitis after phacoemulsification. In accordance with the study protocol, a mid-inclusion interim analysis of the safety of the study drug was performed.

PATIENTS AND METHODS

Patients with suspected endophthalmitis after phacoemulsification were asked to participate in this study. A diagnostic vitreous biopsy was taken and the patients received intravitreal injections of 400 micrograms dexamethasone or a placebo, plus 0.2 mg vancomycin and 0.05 mg gentamicin. Injections were repeated after 3 or 4 days. The safety analysis included: the number of eyes with an evisceration; no light perception; or a visual acuity of less than 5/200. Treatment outcome was evaluated in terms of: the percentage of patients with a visual acuity of 20/40 or more and 20/100 or more.

RESULTS

The interim analysis included 81 patients with at least 1 year follow-up. Sixty-three patients (65 %) were culture-positive. Safety analysis: 7 eyes were eviscerated (3 dexamethasone, 4 placebo); 4 eyes had no light perception (2 dexamethasone, 2 placebo); and 4 eyes had less than 5/200 vision (3 dexamethasone, 1 placebo). Treatment outcome: 70 % of patients had a visual acuity of at least 20/40.

CONCLUSION

The safety analysis does not warrant premature discontinuation of the study. So far, the overall outcome of our treatment regimen, consisting of merely a diagnostic biopsy instead of a vitrectomy and an optimized antibiotic dosing, compares favourably to published literature.

The role of thrombin in proliferative vitreoretinopathy

PURPOSE

To determine the role of thrombin in the development of proliferative vitreoretinopathy (PVR).

METHODS

Vitreous was collected from patients undergoing a vitrectomy (macular holes and puckers, n = 11 [controls]; retinal detachment without PVR development following vitrectomy, n = 15 [RRD1]; retinal detachment with PVR development within 6 months after vitrectomy, n = 11 [RRD2]; and established PVR, n = 14 [PVR]). Thrombin activity in vitreous was determined using a thrombin-specific chromogenic substrate. ARPE-19 cells were stimulated with 8× diluted vitreous samples in the presence and absence of hirudin. The samples were analyzed at t = 0 and t = 24 hours for the presence of 27 cytokines/chemokines and growth factors using a multiplex approach. In comparable studies, ARPE-19 cells were stimulated for 2 hours, and mRNA expression levels for CCL2, CXCL8, GMCSF, IL6, and PDGFB were determined by real-time quantitative (RQ)-PCR.

RESULTS

Thrombin activity was significantly (P < 0.05) higher in vitreous of the PVR group compared to the other groups. Proliferative vitreoretinopathy vitreous stimulated the production of chemokine (C-C motif) ligand (CCL)2, chemokine (C-X-C motif) ligand (CXCL)8, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, and platelet-derived growth factor (PDGF)-BB by ARPE-19 to significantly (P < 0.05) higher levels than vitreous from the RRD1 and RRD2 groups. These effects of PVR vitreous were significantly (P < 0.05) reduced by hirudin. These data were confirmed by mRNA studies.

CONCLUSIONS

Thrombin activity is increased in vitreous of patients with established PVR and is involved in the activation of proinflammatory and profibrotic pathways in RPE cells. Inhibition of thrombin activity may therefore represent a potential treatment option for proliferative vitreoretinopathy.

There is no relation between the occurrence of proliferative vitreoretinopathy and the location of the donor site after transplantation of a free autologous retinal pigment epithelium-choroid graft

PURPOSE

A free autologous retinal pigment epithelium (RPE)-choroid graft can be harvested during transplantation surgery from a 6 or 12 o'clock site in the midperiphery. This study evaluated whether proliferative vitreoretinopathy (PVR) occurs more frequently in patients with an inferior donor site retinotomy, which is not closed by the tamponade and is in contact with the hydrophilic, pro-inflammatory and fibrotic environment, than in patients with a superior donor site retinotomy.

METHODS

Retrospective analysis of a prospective cohort of 246 patients with exudative age-related macular degeneration treated with an RPE-choroid graft transplantation and a lighter-than-water, 5000 centistoke silicone oil endotamponade. The location of the donor site, the presence or absence of PVR development and the location of PVR were noted. The two-tailed Fisher's exact test was used for statistical analysis.

RESULTS

Thirty-nine of 246 (15.9%) patients developed PVR, of whom 35 had a superior donor site and four an inferior donor site. Of the 209 patients without PVR, 155 had a superior donor site and 25 had an inferior one. For 27 patients, no donor site location was explicitly documented in the patient files. We found no difference between the groups with a superior or inferior donor site and the occurrence of PVR (p=0.8).

CONCLUSION

Shifting the inflammatory aqueous milieu away from the graft donor site does not prevent the occurrence of PVR.

Developing cellular therapies for retinal degenerative diseases

Biomedical advances in vision research have been greatly facilitated by the clinical accessibility of the visual system, its ease of experimental manipulation, and its ability to be functionally monitored in real time with noninvasive imaging techniques at the level of single cells and with quantitative end-point measures. A recent example is the development of stem cell-based therapies for degenerative eye diseases including AMD. Two phase I clinical trials using embryonic stem cell-derived RPE are already underway and several others using both pluripotent and multipotent adult stem cells are in earlier stages of development. These clinical trials will use a variety of cell types, including embryonic or induced pluripotent stem cell-derived RPE, bone marrow- or umbilical cord-derived mesenchymal stem cells, fetal neural or retinal progenitor cells, and adult RPE stem cells-derived RPE. Although quite distinct, these approaches, share common principles, concerns and issues across the clinical development pipeline. These considerations were a central part of the discussions at a recent National Eye Institute meeting on the development of cellular therapies for retinal degenerative disease. At this meeting, emphasis was placed on the general value of identifying and sharing information in the so-called "precompetitive space." The utility of this behavior was described in terms of how it could allow us to remove road blocks in the clinical development pipeline, and more efficiently and economically move stem cell-based therapies for retinal degenerative diseases toward the clinic. Many of the ocular stem cell approaches we discuss are also being used more broadly, for nonocular conditions and therefore the model we develop here, using the precompetitive space, should benefit the entire scientific community.

[Laser pointers are not toys; eye injury with permanent loss of visual acuity]

In the nineteen-nineties, there was much hype in the European media about presumed laser pointer maculopathy. However, the recent introduction of more powerful and therefore more dangerous laser pointers and their easy availability on the internet necessitates vigilance on the issue. This is an urgent matter, as here we report three cases of proven maculopathy due to an unsafe laser pointer. Three boys aged 13, 9 and 12 years used an unsafe laser pointer as a toy and looked repeatedly into the pointer, resulting in a permanent reduction in visual acuity due to macular damage. Laser pointers are not designed to be children's toys or instruments to annoy people in a crowd. Health authorities and the ophthalmic community should be aware of the potential danger of improper use of high-output laser pointers and warn the general public before the widespread availability of unsafe laser pointers and consequently laser pointer-induced macular damage becomes a true social problem.

Thrombin induces epithelial-mesenchymal transition and collagen production by retinal pigment epithelial cells via autocrine PDGF-receptor signaling

PURPOSE

De-differentiation of RPE cells into mesenchymal cells (epithelial-mesenchymal transition; EMT) and associated collagen production contributes to development of proliferative vitreoretinopathy (PVR). In patients with PVR, intraocular coagulation cascade activation occurs and may play an important initiating role. Therefore, we examined the effect of the coagulation proteins factor Xa and thrombin on EMT and collagen production by RPE cells.

METHODS

Retinal pigment epithelial cells were stimulated with factor Xa or thrombin and the effect on zonula occludens (ZO)-1, α-smooth muscle actin (α-SMA), collagen, and platelet-derived growth factor (PDGF)-B were determined by real-time quantitative-polymerase chain reaction (RQ-PCR), immunofluorescence microscopy, and HPLC and ELISA for collagen and PDGF-BB in culture supernatants, respectively. PDGF-receptor activation was determined by phosphorylation analysis and inhibition studies using the PDGF-receptor tyrosine kinase inhibitor AG1296.

RESULTS

Thrombin reduced ZO-1 gene expression (P < 0.05) and enhanced expression of the genes encoding α-SMA and the pro-alpha1 chain of collagen type-1 (P < 0.05), indicating EMT. Also, ZO-1 protein expression declined on thrombin stimulation, whereas production of α-SMA and collagen increased. In contrast to thrombin, factor Xa hardly stimulated EMT by RPE. Thrombin clearly induced PDGF-BB production and PDGF-Rβ chain phosphorylation in RPE. Moreover, AG1296 significantly blocked the effect of thrombin on EMT and collagen production.

CONCLUSIONS

Our findings demonstrate that thrombin is a potent inducer of EMT by RPE via autocrine activation of PDGF-receptor signaling. Coagulation cascade-induced EMT of RPE may thus contribute to the formation of fibrotic retinal membranes in PVR and should be considered as treatment target in PVR.

A free retinal pigment epithelium-choroid graft in patients with exudative age-related macular degeneration: results up to 7 years

PURPOSE

To report and analyze long-term best-corrected visual acuity (BCVA) outcomes following a free autologous retinal pigment epithelium (RPE)-choroid graft translocation in patients with exudative age-related macular degeneration (AMD).

DESIGN

Prospective cohort study.

METHODS

SETTING

Institutional.

STUDY POPULATION

One hundred and thirty consecutive patients (133 eyes) with AMD underwent RPE-choroid graft translocation between October 2001 and February 2006. All patients had a subfoveal choroidal neovascular membrane with or without hemorrhage and/or an RPE tear. All were either ineligible for or nonresponsive to photodynamic therapy, the standard treatment at the time of surgery.

OBSERVATION PROCEDURES

Data collection included preoperative and postoperative visual acuity measurements, fundus photography, fluorescein and indocyanine green angiography, and microperimetry.

MAIN OUTCOME MEASURES

Postoperative BCVA.

RESULTS

The mean preoperative BCVA was 20/250. Four years after surgery, 15% of the eyes had a BCVA of >20/200, and 5% had a BCVA of ≥20/40. One patient achieved a BCVA of 20/32, which was maintained at 7 years after surgery. Complications consisted of proliferative vitreoretinopathy (n = 13), recurrent neovascularization (n = 13), and hypotony (n = 2).

CONCLUSIONS

RPE-choroid graft transplantation may maintain macular function for up to 7 years after surgery, with relatively low complication and recurrence rates. Retinal sensitivity, BCVA data, and fixation on the graft suggest that the graft, rather than simply the removal of submacular hemorrhage and/or choroidal neovascular membrane, was responsible for the preservation of macular function. This surgery may be an alternative for patients with AMD who cannot undergo other standard treatment.

Phase-stabilized optical frequency domain imaging at 1-µm for the measurement of blood flow in the human choroid

In optical frequency domain imaging (OFDI) the measurement of interference fringes is not exactly reproducible due to small instabilities in the swept-source laser, the interferometer and the data-acquisition hardware. The resulting variation in wavenumber sampling makes phase-resolved detection and the removal of fixed-pattern noise challenging in OFDI. In this paper this problem is solved by a new post-processing method in which interference fringes are resampled to the exact same wavenumber space using a simultaneously recorded calibration signal. This method is implemented in a high-speed (100 kHz) high-resolution (6.5 µm) OFDI system at 1-µm and is used for the removal of fixed-pattern noise artifacts and for phase-resolved blood flow measurements in the human choroid. The system performed close to the shot-noise limit (<1dB) with a sensitivity of 99.1 dB for a 1.7 mW sample arm power. Suppression of fixed-pattern noise artifacts is shown up to 39.0 dB which effectively removes all artifacts from the OFDI-images. The clinical potential of the system is shown by the detection of choroidal blood flow in a healthy volunteer and the detection of tissue reperfusion in a patient after a retinal pigment epithelium and choroid transplantation.

Early perfusion of a free RPE-choroid graft in patients with exudative macular degeneration can be imaged with spectral domain-OCT

PURPOSE

To study early flow and revascularization in a free, autologous, retinal pigment epithelium (RPE)-choroid graft.

METHODS

This prospective cohort study used spectral domain-optical coherence tomography (SD-OCT) after RPE-choroid graft surgery in 12 patients. This SD-OCT was combined with fluorescein angiography (FA) and indocyanine green angiography (ICGA) in 5 patients.

RESULTS

SD-OCT revealed that vessel diameter, number of vessels, and graft thickness increased in 10 of 12 patients, starting between 3 and 10 days after surgery. A subsequent decrease in thickness was found in all 10 patients, beginning as early as 8 days after surgery. Initially, the graft vessels were optically clearer than the underlying choroidal recipient vessels. Between 8 and 30 days after surgery, the optically clear vessels became gray, similar to the recipient choroid. FA and ICGA revealed perfusion in 4 of 5 patients between postoperative days 6 and 15. Between postoperative days 12 and 60, the entire choroidal structure of the graft was visible on ICGA. CONCLUSIONS; These data suggest that enlargement of vessel diameter, increase in the number of choroidal vessels, and graft thickening visualized by SD-OCT correspond with the ingrowth of afferent vessels, as demonstrated by ICGA. The subsequent establishment of efferent vessels results in flow, imaged as a change in color of the graft's vessels from optically clear to gray, graft thinning on SD-OCT, and complete revascularization on ICGA. SD-OCT, a noninvasive examination, can be used to demonstrate early graft perfusion in patients (trialregister.nl/trialreg/admin/rctview.asp number, NTR1768).

Cost-effectiveness of autologous retinal pigment epithelium and choroid translocation in neovascular AMD

AIM

To assess the cost-effectiveness of autologous retinal pigment epithelium and choroid translocation (PATCH) in neovascular age-related macular degeneration (AMD).

METHODS

Visual acuity and complication rates of published patient series were used to determine the incremental utility of treatment for the patient. The utility data applied assume that the better eye was affected. Comparator was a meta-analysis of recent control groups, in which patients received best supportive care. To assess cost-effectiveness, costs per quality adjusted life years (QALYs) and costs of avoiding low vision ("legal blindness", i.e. ≤20/200) were calculated. Costs were based on a German sick fund perspective and in a scenario on US costs. Robustness of the model was investigated by univariate and probabilistic multivariate sensitivity analysis (PSA).

RESULTS

Cost-utility analysis showed surgery to be the dominant ("cost-saving") strategy for Germany and for the US in both, cost-effectiveness and cost-utility analysis (costs per QALY). In the sensitivity analysis the intervention remained dominant or cost-effective in all scenarios investigated. Clinical outcomes and duration of modeling were the most influential factors in the sensitivity analyses.

CONCLUSION

Therapy of neovascular AMD by PATCH is a cost-effective treatment option for selected patients, who are not well suitable for other current treatment options.

The effect of a preoperative subconjuntival injection of dexamethasone on blood-retinal barrier breakdown following scleral buckling retinal detachment surgery: a prospective randomized placebo-controlled double blind clinical trial

Background

Blood–retinal barrier breakdown secondary to retinal detachment and retinal detachment repair is a factor in the pathogenesis of proliferative vitreoretinopathy (PVR). We wished to investigate whether an estimated 700 to 1000 ng/ml subretinal dexamethasone concentration at the time of surgery would decrease the blood–retinal barrier breakdown postoperatively.

Methods

Prospective, placebo-controlled, double blind clinical trial. In 34 patients with rhegmatogenous retinal detachment scheduled for conventional scleral buckling retinal detachment surgery, a subconjunctival injection of 0.5 ml dexamethasone diphosphate (10 mg) or 0.5 ml placebo was given 5–6 hours before surgery. Differences in laser flare photometry (KOWA) measurements taken 1, 3 and 6 weeks after randomisation between dexamethasone and placebo were analysed using mixed model ANOVA, while correcting for the preoperative flare measurement.

Results

Six patients did not complete the study, one because of recurrent detachment within 1 week, and five because they missed their postoperative laser flare visits. The use of dexamethasone resulted in a statistically significant decrease in laser flare measurements at the 1-week postoperative visit.

Conclusion

The use of a preoperative subconjunctival injection of dexamethasone decreased 1-week postoperative blood–retina barrier breakdown in patients undergoing conventional scleral buckling retinal detachment surgery. This steroid priming could be useful as a part of a peri-operative regime that would aim at decreasing the incidence of PVR.

The angio-fibrotic switch of VEGF and CTGF in proliferative diabetic retinopathy

BACKGROUND

In proliferative diabetic retinopathy (PDR), vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF) cause blindness by neovascularization and subsequent fibrosis, but their relative contribution to both processes is unknown. We hypothesize that the balance between levels of pro-angiogenic VEGF and pro-fibrotic CTGF regulates angiogenesis, the angio-fibrotic switch, and the resulting fibrosis and scarring.

METHODS/PRINCIPAL FINDINGS

VEGF and CTGF were measured by ELISA in 68 vitreous samples of patients with proliferative DR (PDR, N = 32), macular hole (N = 13) or macular pucker (N = 23) and were related to clinical data, including degree of intra-ocular neovascularization and fibrosis. In addition, clinical cases of PDR (n = 4) were studied before and after pan-retinal photocoagulation and intra-vitreal injections with bevacizumab, an antibody against VEGF. Neovascularization and fibrosis in various degrees occurred almost exclusively in PDR patients. In PDR patients, vitreous CTGF levels were significantly associated with degree of fibrosis and with VEGF levels, but not with neovascularization, whereas VEGF levels were associated only with neovascularization. The ratio of CTGF and VEGF was the strongest predictor of degree of fibrosis. As predicted by these findings, patients with PDR demonstrated a temporary increase in intra-ocular fibrosis after anti-VEGF treatment or laser treatment.

CONCLUSIONS/SIGNIFICANCE

CTGF is primarily a pro-fibrotic factor in the eye, and a shift in the balance between CTGF and VEGF is associated with the switch from angiogenesis to fibrosis in proliferative retinopathy.

Collagen distribution in the human vitreoretinal interface

PURPOSE

To evaluate the presence of collagen types I to VII, IX, XI, and XVIII at the posterior pole, the equator and the pre-equatorial area in human donor eyes, since collagens are important macromolecules that contribute to vitreoretinal adhesion at the vitreoretinal interface.

METHODS

Freshly isolated human retinectomy samples from the equator were used for reverse transcription-polymerase chain reaction to detect mRNA of the above-mentioned collagens. In addition, human donor eyes and equatorial retinectomy samples were embedded in paraffin, stained with antibodies against the collagens and evaluated by light microscopy (LM).

RESULTS

Retinectomy samples expressed mRNA of all tested collagen types. By LM, vitreous cortex was positive for collagen types II, V, IX, and XI. In all three regions within the donor eyes and in the retinectomy samples, the internal limiting membrane (ILM) showed types IV, VI, and XVIII; the retinal vasculature was positive for types I to VI and XVIII in most specimens; and the retinal layers showed condensed spots of type VII. In addition, type VII increased in density and in distribution over the retinal layers toward the posterior pole.

CONCLUSIONS

Staining patterns of collagen types I to V, IX, XI, and XVIII confirmed previous observations. Important new findings include the presence of type VI in the ILM and type VII in several layers of the retina. Both collagens can anchor matrix components, and type VI could be involved in vitreoretinal attachment. Furthermore, the presence of collagen mRNA in human retinectomy samples may be an indication of postnatal collagen production by retinal cells.