Retinotomy and foveal translocation for surgical management of subfoveal choroidal neovascular membranes

Cell-Based Therapies for Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. The pathogenesis of AMD involves dysfunction and loss of the retinal pigment epithelium (RPE), a monolayer of cells that provide nourishment and functional support for the overlying photoreceptors. RPE cells in mammals are not known to divide, renew or regenerate in vivo, and in advanced AMD, RPE loss leads to degeneration of the photoreceptors and impairment of vision. One possible therapeutic approach would be to support and replace the failing RPE cells of affected patients, and indeed moderate success of surgical procedures in which relatively healthy autologous RPE from the peripheral retina of the same eye was transplanted under the retina in the macular area suggested that RPE replacement could be a means to attenuate photoreceptor cell loss. This prompted exploration of the possibility to use pluripotent stem cells (PSCs) as a potential source for "healthy and young" RPE cells for such cell-based therapy of AMD. Various approaches ranging from the use of allogeneic embryonic stem cells to autologous induced pluripotent stem cells are now being tested within early clinical trials. Such PSC-derived RPE cells are either injected into the subretinal space as a suspension, or transplanted as a monolayer patch upon scaffold support. Although most of these approaches are at early clinical stages, safety of the RPE product has been demonstrated by several of these studies. Here, we review the concept of cell-based therapy of AMD and provide an update on current progress in the field of RPE transplantation.

International Board Members of the American Journal of Ophthalmology

This year marks the 100th anniversary of the "modern" American Journal of Ophthalmology (AJO). International influence has been present since the beginnings of the journal, and the AJO had boasted a number of foreign editorial board members and collaborators over the years. Within the article we present sketches of the deceased international board members of the AJO, particularly of Sir Stewart Duke-Elder, Pierre Amalric, Joaquin Barraquer, and Yasuo Tano. Although the AJO is American by name and with respect to the majority of contributions and readers, the international board members and collaborators have helped to maintain its international character and worldwide level of recognition. As the United States is a competitive society that values progress and success partially owing to foreign influence and immigrants, similarly the international contributions help to support and provoke the dynamic development of the AJO.

Clinical characteristics and current treatment of age-related macular degeneration

Age-related macular degeneration (AMD) is a multifactorial degeneration of photoreceptors and retinal pigment epithelium. The societal impact is significant, with more than 2 million individuals in the United States alone affected by advanced stages of AMD. Recent progress in our understanding of this complex disease and parallel developments in therapeutics and imaging have translated into new management paradigms in recent years. However, there are many unanswered questions, and diagnostic and prognostic precision and treatment outcomes can still be improved. In this article, we discuss the clinical features of AMD, provide correlations with modern imaging and histopathology, and present an overview of treatment strategies.

Major challenges in vitreoretinal surgery

Since the first vitrectomy surgery was used for treatment of vitreoretinal diseases, surgical techniques and instrumentation have been rapidly improved in the past decades. However, there are complicated vitreoretinal diseases that cannot be successfully treated, even with state-of-the-art surgeries. The outcomes of some complicated cases are still poor due to different reasons and debates still remain in some areas regarding what are the best treatments. There is still a lack of full understanding on many complicated vitreoretinal diseases, such as the molecular basis of proliferative vitreoretinopathy (PVR), the role of scleral buckling (SB) in the management of rhegmatogenous retinal detachment (RRD), the optimal surgical consideration for pediatric RD, and the possibility of surgical management for various retinal degenerations and congenital retinal anomalies. This review discusses the current understandings of some complicated vitreoretinal diseases.

Choroidal neovascularization in pathological myopia

Myopic choroidal neovascularization (CNV) is one of the leading causes of visual impairment worldwide. The clinical and socioeconomic impact of myopic CNV in Asian countries is particularly significant due to rising trend in the prevalence and severity of pathological myopia. The exact pathogenesis of myopic CNV remains unclear and there is paucity of information with respect to incidence and risk factors for myopic CNV from prospective studies. Furthermore, there are no recognized measures that may prevent or delay the development of CNV in eyes with pathological myopia. Advances have been made in the diagnosis and characterization of myopic CNV over the years. Until recently, treatment modalities for myopic CNV were limited to thermal laser photocoagulation and photodynamic therapy with verteporfin, both these modalities primarily aim at prevention of further visual loss. In the last 5 years, inhibitors of vascular endothelial growth factor (VEGF) have been used successfully and may improve vision to some extent. Nevertheless, the long-term safety and efficacy of anti-VEGF agents remains unknown. Furthermore, the risk of developing chorioretinal atrophy remains the key factor in determining the final visual outcome. This review article summarizes the current literature on myopic CNV, highlighting new evolving diagnostic and treatment modalities, prognostic factors influencing visual outcome, and areas of future research.

Diplopia and strabismus following ocular surgeries

Postoperative diplopia and strabismus may result from a variety of ocular surgical procedures. Common underlying mechanisms include sensory disturbance, scarring, direct extraocular muscle injury, myotoxicity from injections of local anesthesia or antibiotics, and malpositioning of extraocular muscles by implant materials. The most common patterns are vertical and horizontal motility disturbance. Treatment options include prisms, botulinum, occlusion, or surgery.

Magnetic resonance imaging of the extraocular muscle path before and after strabismus surgery for a large degree of cyclotorsion induced by macular translocation surgery

PURPOSE

To evaluate the changes in the location of the extraocular muscles (EOMs) following strabismus surgery to treat a large degree of torsional diplopia induced by macular translocation surgery.

METHODS

Six consecutive patients who underwent macular translocation surgery with 360 degrees of retinotomy and subsequent strabismus surgery were studied. Magnetic resonance imaging (MRI) was performed before and after the surgery. The angle made by the line connecting the center of the orbit and the center of each rectus muscle and the horizontal was measured. The changes in these angles before and after strabismus surgery were studied.

RESULTS

The average rotation of the globe after strabismus surgery was 28 degrees (SD = 7.21; range, 17 degrees -39 degrees ). The average measured EOM shift was -0.3 degrees (SD = 8.04; range, -20.4 degrees to 20.2 degrees ).

CONCLUSIONS

Despite large torsional rotation of the globe, there was no corresponding torsional repositioning of the deep paths of the rectus muscles. The paths of the operated muscles were essentially unchanged.

Macular translocation for neovascular age-related macular degeneration

BACKGROUND

Macular translocation has been proposed by vitreoretinal surgeons to displace the neuroretinal tissue onto healthy retinal pigment epithelium and choroid when the macula has been invaded by subretinal neovascularisation.

OBJECTIVES

This review aims at assessing the effectiveness of macular translocation for preserving or improving vision in patients with neovascular age-related macular degeneration (AMD).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE and Caribbean Literature on Health Sciences (LILACS). There were no language or date restrictions in the search for trials.The electronic databases were last searched on 21 July 2008.

SELECTION CRITERIA

We included randomised or quasi randomised controlled trials comparing macular translocation with any other treatment or observation.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data. The risk ratio (RR) of visual loss and visual gain was estimated at one year after treatment.

MAIN RESULTS

Only one small unblinded study on 50 people compared full macular translocation with photodynamic therapy (PDT) in AMD patients with predominantly classic subfoveal choroidal neovascularisation (CNV). At the last examination, performed in most of the cases after one year, there was no difference in the rate of visual loss of 3 or more lines (translocation versus PDT: RR 0.56, 95% confidence interval (CI) 0.22 to 1.43), as well as in the mean change of contrast sensitivity (1 letter favouring translocation; 95% CI -3.51 to 5.51) and the rate of recurrence of CNV (translocation versus PDT: RR 1.56, 95% CI 0.83 to 2.91). Other outcomes significantly favoured translocation, such as the gain of 3 or more ETDRS lines (RR 21, 95% CI 1.30 to 340.02), the mean change of visual acuity (mean difference (MD) 14.60, 95% CI 5.39 to 23.81) and the mean change of near visual acuity score (MD 17.80, 95% CI 3.98 to 31.62) which is obtained with an algorithm. Serious complications reported after macular translocation were retinal detachment in 6/25 patients and diplopia requiring prismatic correction in 5/25 patients.

AUTHORS' CONCLUSIONS

There is insufficient evidence from randomised controlled trials on the effectiveness of macular translocation, which is also not free of important risks. Furthermore, this technique is difficult to perform and a long surgical training is required. Future studies might include patients with small neovascular lesions that failed to respond to current pharmacological therapies and are willing to accept the risks associated with surgery to try to improve visual acuity.

Antiangiogenic effect of oral 2-methoxyestradiol on choroidal neovascularization in mice

We evaluated the efficacy of systemic 2-methoxyestradiol (2ME2) in a laser-induced murine model of choroidal neovascularization (CNV). C57BL/6J mice (8-week-old males) were used in this study and divided into four groups. After laser treatment, daily oral treatment with vehicle control, and 30, 50, and 75 mg/kg of 2ME2 was started. Two weeks after laser treatment, digital images of CNV were obtained from fluorescein isothiocyanate-dextran (FITC-dextran) angiography and choroidal flat mount after FITC-dextran perfusion. These images were quantified by NIH image software. Analysis of images from both FITC-dextran angiography and choroidal flat mount with FITC-dextran perfusion demonstrated that the 2ME2 treated groups showed a statistically significant, dose-dependent decrease in CNV. No toxicity or weight loss was observed during the treatment. Significant antiangiogenic effects of oral 2ME2 on laser induced CNV were observed. Since 2ME2 (Panzem) has demonstrated good safety in phase I/II trials for cancer, it has the potential to be used as a novel oral treatment for age-related macular degeneration.

Autologous translocation of the choroid and retinal pigment epithelium in age-related macular degeneration

PURPOSE

To evaluate the autologous translocation of peripheral choroid and retinal pigment epithelium (RPE) in 45 eyes of 43 patients with age-related macular degeneration (AMD).

DESIGN

Prospective nonrandomized study.

METHODS

All patients had visual loss due to AMD (n = 5 classic membranes, n = 14 occult, n = 2 mixed, n = 16 pigment epithelial detachment (PED), n = 5 subretinal hemorrhage, n = 3 geographic atrophy). After extraction of the neovascular complex, an autologous peripheral full-thickness explant of RPE, Bruch membrane, and choroid was translocated from the midperiphery to the macula.

RESULTS

Preoperative distant visual acuity ranged from 20/800 to 20/40. Reading vision ranged from 1.4 logarithm of reading acuity determination (logRAD) to 0.5 logRAD (0.04 to 0.32 Snellen equivalent). Revision surgery was required in 22 eyes as a result of proliferative vitreoretinopathy (PVR), retinal detachment, macular pucker, or vitreous hemorrhage. In eight patients, the patch was renewed. At six months, distant visual acuity ranged from light perception to 20/50 (increase of 15 letters in four eyes). Reading vision ranged from 1.4 to 0.4 logRAD. Visual outcome was unrelated to the type of AMD. Vascularization of the transplant was visible on indocyanine green (ICG) angiography in 40 of 42 eyes. In most patients, autofluorescence of the pigment epithelium was coincident with revascularization of the graft. Fixation on the patch was positively related to visual acuity.

CONCLUSIONS

Autologous translocation of a full-thickness transplant of choroid and RPE usually results in a vascularized and functioning graft. Vascularization was even achieved in patients with geographic atrophy. Fixation stability and microperimetry before the patch translocation may be helpful in selecting patients who will profit from surgery.

Surgical management of age-related macular degeneration

The development of increasingly refined vitreoretinal surgical techniques has resulted in a variety of surgical procedures for age-related macular degeneration (AMD). These have included submacular surgery with removal of choroidal neovascular membranes and subretinal blood, intraoperative lysis of feeder vessels, pneumatic displacement of subretinal blood and macular translocation surgery. The goals of these procedures have been to improve upon the poor natural history of exudative AMD and restore useful central vision. This article reviews the varied approaches, results and complications of the surgical management of AMD.

Two-year results of macular translocation with scleral infolding in myopic choroidal neovascularisation

PURPOSE

To assess the two year outcome following macular translocation (MT) with scleral infolding in the management of myopic subfoveal choroidal neovascularisation (CNV).

DESIGN

Prospective, clinical interventional noncomparative consecutive case series.

PARTICIPANTS

79 eyes of 79 patients with myopic subfoveal CNV and less than 6 months of duration of the symptoms.

INTERVENTION

MT with scleral infolding.

MAIN OUTCOME MEASURES

Visual Acuity (VA), reading ability of 12 point Arial letter sentences at a reading distance without magnifying systems and foveal displacement.

RESULTS

Mean preoperative VA was 20/125, after two years the mean VA was 20/80. Reading ability of 12 point Arial letter sentences at a reading distance (33 cm) was obtained in 59% of the eyes at one year, descending to 43% at two years. Mean foveal displacement after surgery was 942 microns. Intraoperative complications have been: retinal breaks (21.5%) and choroidal haemorrhage not affecting the posterior pole (3.7%). Main postoperative complications have been: Insufficient foveal displacement: 20%; Retinal detachment: 8.8%; Subfoveal recurrence: 28%; macular fold: 2.5% and macular hole: 1.2%.

CONCLUSION

MT with scleral infolding offers the opportunity to recover central vision and reading ability in patients with myopic CNV but it remains unpredictable.

FOVEAL SENSITIVITY AND FIXATION STABILITY BEFORE AND AFTER MACULAR TRANSLOCATION WITH 360-DEGREE RETINOTOMY

PURPOSE

To evaluate the functional changes of the fovea by scanning laser ophthalmoscopy (SLO) fundus perimetry after macular translocation with 360-degree retinotomy, and to determine whether the preoperative macular function estimated by the sensitivity of the fovea and the stability of fixation can predict visual acuity after the surgery.

METHODS

Macular translocation with 360-degree retinotomy and simultaneous torsional muscle surgery were performed on 25 eyes of 25 patients with choroidal neovascularization. The index of foveal sensitivity (Isens) and the index of fixation stability (Ifix) before and after surgery were calculated from the microperimetric data. The preoperative Isens and Ifix were compared with postoperative Isens and Ifix, respectively. The correlations of preoperative Isens and Ifix with the visual acuity after the translocation surgery (VApost) were calculated.

RESULTS

Isens increased in 14 (56%) of 25 eyes. Ifix improved in 10 (40%) of 25 eyes. The preoperative Isens and VApost were moderately correlated (r = 0.434, P = 0.0295), while the preoperative Ifix and VApost were highly correlated (r = - 0.530, P = 0.0057).

CONCLUSION

An increase in foveal sensitivity and an improvement in the fixation stability were demonstrated quantitatively by microperimetry. The preoperative foveal sensitivity and fixation stability were correlated with the postoperative visual acuity. Microperimetry using SLO can be used to investigate foveal function before and after the translocation and to predict the postoperative visual acuity.

Retinal changes after macular translocation with 360-degree retinotomy in monkey eyes

PURPOSE

To determine the morphologic and functional changes of the fovea and retina of monkey eyes after macular translocation with 360-degree retinotomy.

DESIGN

Experimental study.

METHODS

The retinas of eight monkey eyes were surgically translocated with a 360-degree retinotomy with procedures similar to those used on human eyes. At 1, 2, and 3 months after the surgery, the six eyes that had successful surgery were studied by light and transmission electron microscopy, terminal deoxynucleotidyl transferase (TdT)-dNTP terminal nick-end labeling (TUNEL) assay, and immunohistochemistry with peanut agglutinin (PNA) lectin and glial fibrillary acidic protein (GFAP). Retinal physiology was assessed by scotopic and photopic electroretinograms (ERGs).

RESULTS

The fovea was successfully translocated approximately 30 to 40 degrees superiorly in six eyes. The translocated macula and fovea had a normal layered architecture with no TUNEL-positive cells, minimal misalignment of the outer segments, and strong immunoreactivity to GFAP. The mean amplitudes of the scotopic and photopic b-waves were significantly reduced at 1 month after the surgery, and there was only a slight recovery at 3 months. No significant changes were observed in the mean implicit times after the surgery.

CONCLUSION

These findings indicate that macular translocation surgery with 360-degree retinotomy results in minimal morphologic alterations but significant depression of electrophysiologic function.

Morphologic and angiographic assessment of the macula after macular translocation surgery with 360 degrees retinotomy

PURPOSE

To compare the optical coherence tomographic assessment of retinal thickness and the fluorescein angiographic appearance after macular translocation surgery for subfoveal choroidal neovascularization.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty-three consecutive eyes.

INTERVENTION AND TESTING

Optical coherence tomography and fluorescein angiography were performed before and 6 to 15 months (mean +/- standard error [SE], 10.4+/-0.7) after macular translocation surgery with a 360 degrees retinotomy in 23 patients, ages 48 to 79 years, with age-related macular degeneration (12 eyes), polypoidal choroidal vasculopathy (2 eyes), and high myopia (9 eyes). The diameter of the choroidal neovascularizations ranged from 0.3 to 2.6 disc diameters (mean +/- SE, 1.2+/-0.2), and the angle of rotation of the retina ranged from 11 degrees to 45 degrees (mean +/- SE, 29.1+/-2.1 degrees ).

RESULTS

The preoperative best-corrected visual acuity ranged from hand motions to 20/100, and the postoperative best-corrected visual acuity ranged from 20/667 to 20/25. Optical coherence tomography demonstrated a concave foveal configuration after surgery in all 23 eyes, with a mean foveal thickness of 150+/-11 micro m (mean +/- SE). Fluorescein angiography showed various degrees of fluorescein leakage with a pattern similar to cystoid macular edema in 16 of 23 eyes (70%).

CONCLUSIONS

The newly located macula after macular translocation surgery with a 360 degrees retinotomy had cystoid macular edema on fluorescein angiography and normal macular configuration with normal thickness in optical coherence tomography.

Review Article. New treatments in age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of legal blindness in individuals 50 years and older in the developed world. Choroidal neovascularization (CNV) in exudative AMD is responsible for the majority of severe vision loss. Until recently, laser photocoagulation was the only well-established and widely accepted treatment for CNV. However, it is beneficial only for a small subset of patients, has a high rate of CNV persistence and recurrence and results in iatrogenic, collateral damage to the overlying retina. These issues make it difficult to recommend in the case of subfoveal lesions. Consequently, numerous experimental therapeutic interventions are under investigation with the common objective of destroying the CNV but leaving the foveal neurosensory retina intact. Treatment modalities can be grouped into five major categories: photodynamic therapy; radiotherapy; transpupillary thermotherapy; anti-angiogenic and angiostatic agents; and surgical intervention. The present review aims to explain the rationale behind these new treatments, analyse the evidence for their safety and efficacy, determine their stage of development and indicate in which patients they are potentially useful.

One year follow up of macular translocation with 360 degree retinotomy in patients with age related macular degeneration

AIM

To evaluate the benefits of macular translocation with 360 degree retinotomy in patients with exudative age related macular degeneration (ARMD).

METHODS

A consecutive interventional case series was performed on patients who underwent macular translocation between June 1997 and January 2000 at the department of ophthalmology, University of Aachen, Germany. A retrospective pilot study was set up with a minimum follow up of 12 months in 39 consecutive patients with subfoveal choroidal neovascularisation secondary to ARMD. The surgical technique included pars plana vitrectomy, induction of retinal detachment, 360 degree retinotomy, removal of the choroidal neovascular membranes (CNVM), macular translocation, peripheral laser retinopexy, and silicone oil endotamponade.

RESULTS

18 patients showed predominantly occult CNVM, six patients had predominantly classic CNVM, and 15 showed subretinal haemorrhage. At the 12 month follow up 13 patients (33%) showed an improvement in visual acuity of more than three lines (logMAR scale), 18 patients (46%) retained stable visual acuity with a change of equal or less than three lines (logMAR scale), and eight patients (21%) showed a decrease in visual acuity of more than three lines (logMAR scale). Recurrence of CNVM was observed in three (8%) eyes at 5-11 months postoperatively. Other complications included proliferative vitreoretinopathy with retinal detachment (n=10), peripheral epiretinal membranes (n=9), macular pucker (n=2), corneal decompensation (n=2), and hypotony (n=11). 18 patients (46%) complained about persistent diplopia.

CONCLUSION

Macular translocation surgery is able to maintain or improve distant vision in the majority of patients with exudative ARMD. Proliferative vitreoretinopathy and diplopia are the two major complications. A prospective randomised controlled trial comparing macular translocation with observation for patients with the occult form of exudative ARMD may be justified.

Age-related macular degeneration: etiology, pathogenesis, and therapeutic strategies

Age-related macular degeneration is the principal cause of registered legal blindness among those aged over 65 in the United States, western Europe, Australia, and Japan. Despite intensive research, the precise etiology of molecular events that underlie age-related macular degeneration is poorly understood. However, investigations on parallel fronts are addressing this prevalent public health problem. Sophisticated biochemical and biophysical techniques have refined our understanding of the pathobiology of drusen, geographic atrophy, and retinal pigment epithelial detachments. Epidemiological identification of risk factors has facilitated an intelligent search for underlying mechanisms and fueled clinical investigation of behavior modification. Gene searches have not only brought us to the cusp of identifying the culpable gene loci in age-related macular degeneration, but also localized genes responsible for other macular dystrophies. Recent and ongoing investigations, often cued by tumor biology, have revealed an important role for various growth factors, particularly in the neovascular form of the condition. Transgenic and knockout studies have provided important mechanistic insights into the development of choroidal neovascularization, the principal cause of vision loss in age-related macular degeneration. This in turn has culminated in preclinical and clinical trials of directed molecular interventions.

Angiographic characteristics in patients undergoing macular translocation for subfoveal choroidal neovascularization secondary to age-related macular degeneration

PURPOSE

To review in a standardized fashion pre- and postoperative fluorescein angiographic characteristics in patients undergoing limited macular translocation (LMT) with scleral imbrication to treat subfoveal choroidal neovascularization (SFCNV) secondary to age-related macular degeneration (AMD). The current study was undertaken to assess any potential effects of the translocation procedure on altering the angiographic characteristics of SFCNV before laser photocoagulation.

METHODS

A consecutive series of patients undergoing LMT for AMD was identified retrospectively. The pre- and postoperative fluorescein angiograms were reviewed in a masked fashion. Angiographic characteristics evaluated included pre- and postoperative lesion components, stability of lesion, and the amount of retinal translocation obtained.

RESULTS

Eighty-eight patients (90 eyes) had angiograms of adequate quality to permit evaluation. Time between the preoperative and the prelaser angiogram ranged from 2 to 84 days (median 7.5 days). Neovascular complexes remained unchanged or decreased in size in 79% of patients. There was no statistically significant difference in lesion size between the pre- and postoperative periods (P = 0.34). Retinal movement ranged from 160 microm to 3,320 microm (median 960 microm), with 61% of cases undergoing effective translocation (i.e., the fovea was moved away from the neovascular complex). None of the lesion components or demographic factors evaluated affected the amount of translocation obtained. Larger lesions were more likely to remain subfoveal following translocation (P = 0.004).

CONCLUSION

The size and lesion characteristics appear relatively stable following translocation. Amount of retinal movement is not associated with angiographic lesion characteristics. Only size was associated with achievement of desired translocation in the final model, with large lesions being less likely to achieve desired translocation. In our study group, the amount of retinal translocation was variable with 61% of cases undergoing effective translocation.

Photoreceptor transplantation in retinitis pigmentosa: short-term follow-up

PURPOSE

To explore the use of adult human photoreceptor transplantation as a treatment for advanced retinitis pigmentosa (RP).

DESIGN

Prospective noncomparative case series.

PARTICIPANTS

Eight patients with advanced RP.

INTERVENTION

Transplantation of adult human cadaver photoreceptor sheets harvested with the excimer laser. No immunosuppression was used postoperatively. Patients were followed for 12 months postoperatively.

MAIN OUTCOME MEASURE

Visual acuity and retinal function measured by psychophysical, electrophysiologic, and clinical testing.

RESULTS

Best-corrected visual acuity (Bailey-Lovie chart), median reading speed, contrast sensitivity, and visual fields for the operated eye were not statistically significantly improved postoperatively. The amplitude and latency of the maculoscope electroretinogram, as well as the log threshold for dark adaptation, did not change between the operated and control (unoperated) eye. There was no detectable homograft reaction on slit-lamp biomicroscopy or fluorescein angiography. The only adverse effect observed was one patient who complained of monocular diplopia after retinal transplantation and subsequent cataract surgery.

CONCLUSIONS

Allogeneic adult human photoreceptor transplantation is feasible in RP but was not associated with rescue of central vision or a delay in visual loss. However, any possible slowing in the rate of retinal degeneration will take many years to determine.

Pathologic myopia: where are we now?

PURPOSE

To describe current concepts and available treatments for pathologic myopia.

DESIGN

Review of experimental and clinical studies.

METHODS

The demography, natural history, medical and surgical treatments for choroidal neovascular membrane, vitreoretinal interface disorders and future strategies for pathologic myopia are reviewed.

RESULTS

Several medical and surgical modalities are currently available to treat various complications of pathologic myopia. Macular translocation appears to stabilize or improve visual function in many eyes with choroidal neovascularization.

CONCLUSION

Newer strategies are emerging to better ameliorate or prevent the complications of pathologic myopia.

Macular translocation with 360 degree retinotomy for management of age-related macular degeneration with subfoveal choroidal neovascularization

PURPOSE

The aim of this study is to evaluate the functional outcome in a group of patients treated with full macular translocation (FMT) with 360-degree retinotomy for treatment of age-related macular degeneration (ARMD) with subfoveal choroidal neovascularization.

DESIGN

Consecutive interventional case series.

METHODS

Fifty consecutive eyes (50 patients) with ARMD and subfoveal neovascularization who underwent a FMT in our department from January 1999 to July 2000 are included in this study. Compensatory muscle surgery, as described by Eckardt and associates, was performed on all the eyes. The median follow-up is 21 months (range, 12 to 36; SD, 5.4).

RESULTS

The best-corrected postoperative visual acuity (BCVA) was improved by 2 or more Snellen lines in 33 eyes (66%) and remained stable (+/-1 line) in 14 eyes (28%). Only 3 eyes (6%) experienced a deterioration of the BCVA of 2 or more lines. The final BCVA was 20/50 or better in 32% of the cases; only 8 eyes (16%) had a final BCVA < 20/200. Thirty-four (68%) patients are able to read newspaper print (3.3/10) with normal (+3 diopters to +4 diopters) or increased (+5 diopters to +8 diopters) reading ads. Other patients are able to read with magnifying systems. Complications included proliferative vitreoretinopathy (PVR) in 9 eyes (18%), recurrent choroidal neovascularization in 5 eyes (10%), diplopia in 3 eyes (6%), choroidal hemorrhage in 2 eyes (4%), macular hole in 1 eye, and temporary hypotony in 1 eye.

CONCLUSIONS

As 68% of the patients in the study group regained reading vision with reading glasses, FMT can be considered an effective approach in cases of subfoveal choroidal neovascularization. Further investigations are necessary to determine which patients will have the most benefit from this complex therapeutic method.

Extracellular matrix ligands promote RPE attachment to inner Bruch's membrane

PURPOSE

To determine if resurfacing layers of human Bruch's membrane with extracellular matrix ligands increases adult human retinal pigment epithelium (RPE) attachment.

METHODS

We removed successive layers of Bruch's membrane sequentially by mechanical or enzymatic means to expose the RPE basal lamina, inner collagen layer, and elastin layer. Each layer was coated with extracellular matrix proteins (4 microg/cm(2) laminin, 4 microg/cm(2) vitronectin, 20 microg/cm(2) fibronectin, 20 microg/cm(2) collagen IV) for 2 hrs at 37 degrees C. First passage adult human RPE (15000 cells/6 mm explant) were plated onto coated or uncoated Bruch's membrane layers and RPE attachment was measured 18 hrs later.

RESULTS

The reattachment rate to basal lamina derived from younger (age < 50) donors was higher than older (age >/= 70) donors (56.2 +/- 4.8% versus 46.7 +/- 0.7% respectively; p < 0.05). Coating with laminin or collagen IV increased RPE attachment to older but not younger basal lamina. The reattachment rate to inner collagen derived from younger donors was higher than older donors (51.3 +/- 2.7% versus 37.4 +/- 1.7% respectively, p < 0.05). Coating with laminin, fibronectin or collagen IV increased RPE attachment to older but not younger inner collagen layer. Adding extracellular matrix ligands did not increase RPE attachment to elastin.

CONCLUSIONS

RPE attachment is increased by adding ligands to the basal lamina or inner collagen layer but not to the elastin layer. This may be important if the elastin layer is exposed in AMD patients after submacular surgery.

Retinal pigment epithelium translocation after choroidal neovascular membrane removal in age-related macular degeneration

PURPOSE

To test the feasibility of a new surgical technique and to assess visual function over the translocated retinal pigment epithelium (RPE) cells in patients operated on for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (ARMD).

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Nine patients with previously untreated exudative ARMD underwent surgical excision of the subfoveal CNV with RPE translocation and were observed for 12 to 32 months.

METHODS

The surgery consisted of a standard three-port pars plana vitrectomy, excision of the CNV, and RPE translocation. Pre- and postoperative ocular examination included best-corrected visual acuity measurement, fundus color stereo photography, and fundus fluorescein angiography. Optical coherence tomography and confocal laser scanning ophthalmoscopy (cLSO) were performed after surgery. A crossfixation target and a single-point flashing light were projected on different areas of the posterior pole using a cLSO. Photopic 10 to 2 perimetry, photopic fine matrix mapping, and cLSO microperimetry were also performed after surgery in six patients.

MAIN OUTCOME MEASURES

Optical coherence tomography cross-sectional scans and cLSO RPE autofluorescence were recorded to detect the presence of viable translocated RPE. Visual acuity, fixation, photopic 10 to 2 perimetry, photopic fine matrix mapping, and cLSO microperimetry were used to test central visual function.

RESULTS

Retinal pigment epithelium was translocated successfully at the time of CNV removal from the edge of the RPE defect to a subfoveal location in seven of nine patients. One patient experienced proliferative vitreoretinopathy, but significant hemorrhage was not a feature. Optical coherence tomography showed the translocated RPE as an area of increased optical reflectivity with optical shadowing external to it. Confocal laser scanning ophthalmoscopy showed autofluorescence of the translocated RPE. The crossfixation target was seen when projected on the translocated RPE. During eccentric fixation, the patients could see a flashing point-target projected on the translocated RPE. Photopic 10 to 2 perimetry, photopic fine-matrix mapping, and cLSO microperimetry showed the presence of central visual function.

CONCLUSIONS

The authors propose that translocation of RPE at the time of CNV removal, from the edge of the RPE defect to a subfoveal location, may have a role in the surgical management of ARMD.

Retinal pigment epithelium translocation and central visual function in age related macular degeneration: preliminary results

PURPOSE

To test the feasibility of a new surgical technique, and to assess visual function over the translocated retinal pigment epithelium (RPE) cells in patients operated upon for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

MATERIALS AND METHODS

Six patients presenting previously untreated exudative AMD underwent surgical excision of the subfoveal CNV with RPE translocation and were followed from 1 to 10.5 months. The surgery consisted of a standard three port pars plana vitrectomy (TPPPV), excision of the CNV and RPE translocation. Pre and post-operative ocular examination included best-corrected visual acuity measurement, fundus color stereo photography and fundus fluorescein angiography. Optical coherence tomography (OCT) and confocal laser scanning ophthalmoscopy (cLSO) were performed post-operatively. A cross fixation target and a single-point flashing light were projected on different areas of the posterior pole using a cLSO. Photopic 10-2 perimetry, photopic fine matrix mapping, cLSO microperimetry were also performed pre and post-operatively in four patients. OCT cross-sectional scans and cLSO RPE autofluorescence were recorded to detect the presence of viable translocated RPE. Visual acuity, fixation, photopic 10-2 perimetry, photopic fine matrix mapping and cLSO microperimetry were tested for the presence of central visual function.

RESULTS

RPE could be effectively translocated at the time of CNV removal from the edge of the RPE defect to a subfoveal location. OCT showed the translocated RPE as an area of increased optical reflectivity with optical shadowing external to it. cLSO showed autofluorescence of the translocated RPE. The cross fixation target was seen when projected on the translocated RPE. During eccentric fixation, the patients could see a flashing point-target projected on the translocated RPE. Photopic 10-2 perimetry, photopic fine matrix mapping and cLSO microperimetry showed presence of central visual function.

CONCLUSIONS

The authors propose that translocation of RPE at the time of CNV removal, from the edge of the RPE defect to a subfoveal location, may have a role in the surgical management of AMD.

Limited macular translocation with scleral retraction suture

BACKGROUND/AIMS

Macular translocation with scleral imbrication is a new technique for treating subfoveal choroidal neovascular membranes (CNV). This procedure shortens the sclera but may result in a minimal decrease in the internal circumference of the globe and limits the amount of foveal displacement. The authors propose a new scleral retraction suture aimed at decreasing the internal circumference of the globe in an effort to increase foveal displacement.

METHODS

Using a cadaver model, they compared the amount of scleral shortening using a standard scleral imbrication technique and a modified three suture scleral retraction technique. Sections of the globes were digitised and specialised software was used to estimate the amount of scleral shortening. Three patients with subfoveal choroidal neovascularisation underwent limited macular translocation using pars plana vitrectomy and macular detachment with the modified scleral suture technique. The main outcome measures were visual acuity, foveal displacement, and complications.

RESULTS

In the cadaver model, the scleral retraction suture resulted in a flatter internal scleral fold compared to the standard suture technique and created approximately 890 microm of effective scleral shortening. In the patients who underwent macular translocation and laser photocoagulation of the CNV, visual acuity improved in two patients and worsened in one patient. The range of foveal displacement was 1400-2400 microm.

CONCLUSION

The foveal displacements achieved in this limited study compared to median displacement previously published using standard suture techniques demonstrates that the scleral retraction suture technique may be a useful adjunct to limited macular translocation. The advantage of this type of suture in conjunction with translocation may depend on the effective scleral shortening offered by this retraction suture.

Long-term visual acuity after argon green laser photocoagulation of juxtafoveal choroidal neovascularization in highly myopic eyes

PURPOSE

To evaluate visual outcomes in patients with high myopia afterjuxtafoveal choroidal neovascularization (CNV) treated with argon green laser photocoagulation.

PATIENTS AND METHODS

We retrospectively analyzed 23 eyes of 21 patients with high myopia (>6.0 diopters and/or axial length >26 mm) with juxta foveal CNV treated with direct Argon green laser photocoagulation. Mean age at diagnosis was 49.08+/-12.20 years (range, 29 to 71). Mean follow-up was 54.26+/-26.18 months (range 18 to 96).

RESULTS

Best corrected visual acuity (BCVA) before treatment was 0.09+/-0.10 (range, 0.01 to 0.40). Two months after treatment it was 0.14+/-0.12 (0.01 to 0.6), significant difference (p=0.02, Student's t-test forpaired data) and aftersix months 0.19+/-0.14 (0.01 to 0.5) (p=0.0002). Mean BCVA decreased with follow-up, to 0.19+/-0.15 (0.01 to 0.4) after two years, 0.16+/-0.15 (0.01 to 0.5) after three years and 0.16+/-0.19 (0.01 to 0.7) after four years, with no significant improvement after the third year (p=0.04). In two cases CNV reappeared.

CONCLUSIONS

Direct argon green laser photocoagulation in high-myopia juxtafoveal CNV can improve BCVA initially for between two and 24 months. The improvement fades with time, and is no longer significant after the third year.

Surgical removal of subfoveal choroidal neovascularization without removal of posterior hyaloid: a consecutive series in younger patients

PURPOSE

Subfoveal choroidal neovascularization (CNV) remains a common and important cause of visual loss. Previous studies have suggested that submacular surgery may improve or maintain visual acuity, particularly in younger patients. The majority of reported cases included removal of the posterior hyaloid during vitrectomy. The authors present a consecutive series of patients age 55 or younger with subfoveal CNV removal without posterior hyaloid removal.

METHODS

Seventeen patients without age-related macular degeneration (ARMD), with subfoveal CNV from choroiditis, presumed ocular histoplasmosis syndrome, myopia, or idiopathic causes, underwent a small retinotomy technique to extract the membranes after vitrectomy without posterior hyaloid removal.

RESULTS

Median improvement in visual acuity was from 20/320 to 20/50. Eleven patients (65%) experienced an improvement of three or more lines of Snellen acuity (average 7.5), 4 (23%) were within two lines of preoperative acuity, and 2 (12%) had decreased acuity, with an average follow-up of 12 months (range 3-31). Choroidal neovascularization recurred in six patients (35%). Postoperative retinal detachment, epiretinal proliferation, or macular hole did not occur.

CONCLUSIONS

In this series of younger patients with subfoveal CNV not from ARMD, visual acuity was improved in the majority after submacular membrane removal. Omission of removal of the posterior hyaloid did not adversely affect outcome.

Efficacy of Prinomastat) (AG3340), a matrix metalloprotease inhibitor, in treatment of retinal neovascularization

PURPOSE

To study the activity of the novel anti-angiogenic compound AG3340 (Prinomastat), a selective inhibitor of matrix metalloproteases, in an animal model of retinal neovascularization.

METHODS

C57BL/6J mice were used to produce oxygen-induced retinal neovascularization. Mice were exposed to room air from birth (P0) to postnatal 7 days (P7) and to hyperoxia (75% oxygen) for the next 5 days. On postnatal day 12 (P12) the animals were returned to the room air and were treated until postnatal day 16 (P16) with intraperitoneal injections of AG 3340. Four groups were assigned: no drug, 1.6 mg/kg/day, 16 mg/kg/day and 48 mg/kg/day. On day 17 (P17) the animals were sacrificed and the eyes prepared for histological sectioning. Preretinal neovascularization was assessed by counting neovascular nuclei of endothelial cells in the preretinal side of the internal limiting membrane (ILM). The use of animals for this study complies with the ARVO guidelines for animal research.

RESULTS

AG3340 administered systemically by intraperitoneal injections inhibited hypoxia-induced retinal neovascularization. The inhibition was dose dependent with highly significant decrease of neovascular nuclei counts among eyes treated with 0, 1.6 mg/kg, 16 mg/kg and 48 mg/kg doses. There appears to be a saturation effect of inhibition at the level of 70% at the two highest doses of 16 mg/kg and 48 mg/kg.

CONCLUSIONS

AG3340 administered systemically significantly inhibits oxygen-induced retinal neovascularization in an animal model and appears to be a promising candidate for the treatment of neovascular retinal diseases.

Comparison of three techniques of foveal translocation in patients with subfoveal choroidal neovascularization resulting from age-related macular degeneration

PURPOSE

To report the results of three methods of foveal translocation in the presence of subfoveal choroidal neovascular membrane resulting from age-related macular degeneration.

METHODS

We treated 51 eyes of 51 consecutive patients with subfoveal choroidal neovascular membranes resulting from age-related macular degeneration with one of three techniques of foveal translocation surgery: foveal translocation with partial retinotomy (n = 6), limited translocation (n = 9), and translocation with 360-degree retinotomy (n = 36). All patients were followed for at least 6 months postoperatively. The size of the choroidal neovascular membrane and the amount of foveal displacement, the best-corrected visual acuity, and complications were recorded preoperatively and postoperatively.

RESULTS

The mean distance of the foveal translocation was greater in the 360-degree retinotomy group (3340 microm) than in the partial retinotomy (1060 microm, P <.001) and the limited translocation groups (1120 microm, P <.001). A final visual acuity of 20/200 or better was achieved in two eyes (33%) in the partial retinotomy group, seven eyes (78%) in the limited translocation group, and 23 eyes (64%) in the 360-degree retinotomy group. The final visual acuity improved by 0.2 logarithm of minimal angle of resolution (logMAR) unit or more in one eye (17%), one eye (11%), and seven eyes (19%), respectively. The final visual acuity was maintained within 1 line in zero eyes, five eyes (56%), and 19 eyes (53%), respectively. A retinal detachment developed postoperatively in five eyes (83%), zero eyes (0%), and 15 eyes (42%), respectively.

CONCLUSIONS

A significant number of patients improved or maintained best-corrected visual acuity after translocation with 360-degree retinotomy, and limited translocation, whereas translocation with 360-degree retinotomy is suitable for larger choroidal neovascular membranes because it resulted in the greatest foveal displacement among the three translocation procedures.

Drug targeting to choroidal neovascularization

Subfoveal choroidal neovascularization (CNV) causes significant visual loss, especially in patients with age-related macular degeneration (AMD). Several pharmaceutical treatments that use anti-angiogenic agents have been tried to inhibit the activity of CNV experimentally and clinically. In general, however, systemically administered drugs may reach not only targeted tissues but also other tissues, resulting in unwanted side effects. Also, to maintain therapeutic levels of the drugs in targeted tissues, frequent administration for an extended period of time is required. To solve these problems, drug delivery systems targeted to the CNV are being developed. Anatomic characteristics of CNV tissues resemble those of tumor vasculature, exhibiting enhanced permeability and retention effect. Drug targeting to CNV may be feasible in the same manner as it is to tumors. In this review, we describe two approaches of drug targeting to CNV: passive targeting and active targeting.

Electrophysiological changes after 360 degrees retinotomy and macular translocation for subfoveal choroidal neovascularisation in age related macular degeneration

AIM

To evaluate electrophysiological changes after 360 degrees retinotomy and macular translocation for subfoveal choroidal neovascularisation in patients with age related macular degeneration (AMD).

METHODS

A consecutive series of 32 patients suffering from subfoveal choroidal neovascularisation secondary to AMD underwent 360 degrees retinotomy and macular translocation. The ERG served as the main parameter of the study and was recorded 1 day before the translocation surgery and no earlier than 4 weeks after the silicone oil removal.

RESULTS

The scotopic ERG amplitudes were significantly reduced after translocation surgery. Depending on the applied flash luminance the mean b-wave amplitude reduction of the scotopic ERG varied between 67% (0.2 cd.s/m2) and 74% (0.03 cd.s/m2). The a-waves and b-waves of the saturating light response decreased significantly by 46% and 59%, respectively. The photopic a-wave and b-wave amplitudes were significantly lower after the translocation surgery resulting in a mean reduction of 27% and 43%, respectively.

CONCLUSIONS

Although macular translocation may provide the potential of preserving and even restoring vision in patients with subfoveal choroidal neovascular membranes secondary to AMD the present study indicates that a significant electrophysiological decrease is caused by surgical procedures associated with this technique. Further research is necessary to clarify if certain modifications of the surgical procedure are able to substantially reduce the neuroretinal trauma.

Macular translocation with chorioscleral outfolding: a pilot clinical study

PURPOSE

A new surgical technique to translocate the macula was used to treat patients with subfoveal choroidal neovascularization secondary to age-related macular degeneration (AMD).

DESIGN

Prospective, interventional case series.

METHODS

Twenty-five eyes of 25 patients underwent macular translocation with either circumferential or radial chorioscleral outfolding using three clip sizes: 2-mm, 3-mm, and 4-mm. Postoperative photocoagulation was performed on only those eyes that had an extrafoveal choroidal neovascular membrane following surgery.

RESULTS

The surgery successfully displaced the fovea in 22 (88%) of the eyes. The median postoperative foveal displacement was 1142 microm (range 0 to 3200 microm). Patients who had radial outfolding with 4-mm clips had the greatest displacement of the fovea (range 1644 to 3200 microm median 1977 microm). The fovea was successfully displaced to a location outside the choroidal neovascular membrane in 17 (68%) of the 25 eyes. The best-corrected visual acuity improved in 11 eyes (median, 17 letters), remained unchanged in 4 eyes, and decreased in 10 eyes (median, 12 letters). Visual acuity increased by a median of 2 letters. The final best-corrected visual acuity was 20/64 in 3 eyes; 20/80 in 3 eyes; 20/100 in 4 eyes; 20/126 in 4 eyes; 20/200 in 4 eyes; 20/250 in 4 eyes; and 20/400 in 3 eyes.

CONCLUSIONS

Macular translocation with radial chorioscleral outfolding using 4-mm clips resulted in the best foveal displacement and improvement in visual function, and was associated with the least amount of vision loss and complications. Further refinements are needed to make this surgical procedure more predictable, and more research (randomized clinical trials) is needed to determine the role of macular translocation in the treatment of subfoveal choroidal neovascularization in patients with AMD.

Foveal translocation with scleral imbrication in patients with myopic neovascular maculopathy

PURPOSE

To report our surgical results of foveal translocation with scleral imbrication in patients with myopic neovascular maculopathy.

DESIGN

Noncomparative, interventional, consecutive case series.

METHODS

Ten eyes of 10 myopic patients with subfoveal neovascular membranes that had undergone foveal translocation with scleral imbrication were recruited for this retrospective study. Inclusion criteria were myopia 6.0 diopters or greater in refractive error (or axial length 26.5 mm or longer), subfoveal choroidal neovascularization, and preoperative best-corrected visual acuity of 20/100 or worse. None of these eyes had undergone prior laser photocoagulation or submacular surgery. The main outcome measures were surgical complications and postoperative visual function.

RESULTS

Postoperatively, visual acuity had improved more than 3 lines in the logarithm of minimum angle of resolution (logMAR) measurement in all eyes. The mean preoperative, postoperative best, and final visual acuity were 0.12, 0.59, and 0.51, respectively. Of the 10 eyes, six achieved a postoperative final visual acuity of 20/40 or better. The mean postoperative foveal displacement was 0.78 disk diameter (range, 0.3--1.3 disk diameter). Two patients underwent a reoperation because of insufficient foveal displacement. Furthermore, one of these two patients required a third operation to reduce an excessive retinal fold involving the fovea induced by the second surgery. Of the 10 patients, two noted transient diplopia. This complaint, however, resolved over time as suppression developed. Although unintentional iatrogenic retinal tears formed intraoperatively in two eyes, these were successfully treated without serious complications. Postoperatively, mild retinal pigment epithelial changes were observed in all cases, but none led to significant deterioration of visual acuity during the follow-up period. All patients but one were followed for a minimum of 6 months.

CONCLUSIONS

In eyes with myopic neovascular maculopathy, foveal translocation with scleral imbrication may be useful in improving visual acuity. Further refinements in surgical technique and assessment of the long-term complications will be needed to make this procedure safer and more useful.

Macular translocation with chorioscleral outfolding: an experimental study

PURPOSE

Macular translocation by chorioscleral infolding has been proposed as a surgical intervention for exudative age-related macular degeneration, but the surgery is unpredictable and can be associated with severe complications. We tested a new surgical technique, macular translocation with chorioscleral outfolding secured by neurosurgical clips.

METHODS

This was a prospective interventional study in two parts; the first in human cadaver eyes and the second in pigs. Chorioscleral infolding was performed on six human donor eyes, and chorioscleral outfolding was performed on an additional six. The inner surface of the eye wall was measured, and then the fold was unfolded and the distance was measured again. In the second half of the study, macular translocation surgery was performed on 33 pig eyes with one of three sclera shortening methods: 1) a circumferential chorioscleral infolding using 5-0 nylon sutures, 2) a circumferential chorioscleral outfolding using scleral clips, or 3) a radial chorioscleral outfolding using scleral clips. Foveal translocation was measured.

RESULTS

The inner wall of the human cadaver eye was shortened in the chorioscleral infolding group by a mean of 1.6 mm, and in the chorioscleral outfolding group by 3.0 mm. In the pig eyes, the fovea was translocated a mean 2377 microm by circumferential suturing, 2582 microm by circumferential clipping, and 3386 microm by radial clipping. Irregular deformation of the globe was more apparent in the circumferential suture group. Undesirable retinal folds often formed after circumferential infolding but not after radial clipping.

CONCLUSION

Radial chorioscleral outfolding with clips is more predictable and effective than infolding. It produces more translocation and prevents folds across the fovea, one of the most undesirable complications in macular translocation surgery.

Retinal pigment epithelial cell transplantation after subfoveal membranectomy in age-related macular degeneration: clinicopathologic correlation

PURPOSE

To report the histopathology after retinal pigment epithelial cell transplantation and subfoveal membranectomy in age-related macular degeneration.

METHODS

An 85-year-old white woman with bilateral choroidal neovascularization underwent subfoveal membranectomy combined with transplantation of a sheet of human adult retinal pigment epithelium (retinal pigment epithelium) under the foveal center in the right eye. The patient was immunosuppressed postoperatively with prednisone, cyclosporine, and azathioprine. The patient died from congestive heart failure 114 days after surgery.

RESULTS

A patch of hyperpigmentation was visible at the transplant site under the foveola after surgery. Mound-like clusters of individual round, large densely pigmented cells were present in the subretinal space and outer retina in this area. There was loss of the photoreceptor outer segments and native retinal pigment epithelium in the center of the transplant bed, with disruption of the outer nuclear layer predominantly over regions of multilayered pigmented cells. Cystic spaces were present in the inner and outer retina. A residual intra-Bruchs membrane component of the original choroidal neovascular complex was present under the transplant site.

CONCLUSIONS

The transplant site contained clusters of round, pigmented cells that did not form a uniform monolayer in most areas. The morphology at the transplant site is consistent with the lack of visual improvement seen after surgery in this patient.