Vitreous levels of placental growth factor correlate with activity of proliferative diabetic retinopathy and are not influenced by bevacizumab treatment.

PurposePlacental growth factor (PlGF) is a member of the VEGF family that plays an important role in experimental models of diabetic retinopathy and retinal neovascularization. We aimed to investigate whether vitreous levels of PlGF correlated with proliferative diabetic retinopathy (PDR) status, VEGF levels, and bevacizumab treatment. We also analysed PDR membranes to confirm the presence of the PlGF receptor, FLT1, in endothelial cells.MethodsThis was a case-control study: undiluted vitreous fluid samples were obtained from 28 active PDR patients without preoperative bevacizumab treatment, 21 active PDR patients with preoperative bevacizumab treatment, 18 inactive PDR patients, and 21 control patients. PlGF and VEGF levels in samples were determined by enzyme-linked immunosorbent assay. Immunohistochemistry for FLT1 was performed on human PDR membranes.ResultsCompared to control, vitreous PlGF levels were higher in both active PDR without bevacizumab (P<0.0001) and with bevacizumab (P<0.0001). There was no significant difference in PlGF between active PDR patients without and with bevacizumab (P=0.56). Compared to active PDR, PlGF levels were significantly reduced in inactive PDR (P=0.004). PlGF levels were highly correlated with VEGF levels in active PDR. VEGFR1 was expressed in endothelial cells in human PDR membranes.ConclusionThe strong correlation of PlGF levels with PDR disease status and expression of FLT1 in human PDR membranes suggest that PlGF has a pathogenic role in proliferative diabetic retinopathy. Therapeutic targeting of PlGF with agents like aflibercept may be beneficial.

A novel locus for Leber congenital amaurosis on chromosome 14q24.

Leber congenital amaurosis (LCA) is a clinically and genetically heterogeneous autosomal recessive retinal dystrophy and the most common genetic cause of congenital visual impairment. We used a DNA pooling strategy comparing the genotypes of affected to unaffected control pools in a genome-wide search for identity-by-descent on a consanguineous Saudi Arabian LCA family. A shift to homozygosity was observed in the affected DNA pool compared with the control pool at linked markers D14S606 and D14S610. Genotyping of individual DNA samples from the entire pedigree for marker D14S74, closely linked to these loci, and several flanking markers confirmed linkage with a ZMAX=13.29 at theta=0.0. These data assign a third locus (LCA3) for LCA to chromosome 14q24. This locus and the previously identified loci are excluded for other Saudi Arabian pedigrees, both confirming that this clinical disorder is genetically heterogeneous and that additional LCA genes remain to be identified.

Retinal detachment surgery in Marfan's syndrome.

BACKGROUND: Retinal detachment is a known complication of Marfan's syndrome. The literature is scarce on the results of surgery in these cases. PURPOSE: To determine the functional and anatomic outcome of retinal detachment surgery in Marfan's syndrome. METHOD: Retrospective review of charts of Marfan's syndrome patients who had retinal detachment surgery at King Khaled Eye Specialist Hospital between 1983 and 1995. RESULTS: Fourteen patients with 16 surgically treated eyes were identified. Retinal detachment was bilateral in 9/13 (69%) patients. The lens was ectopic in all eyes. Retinal breaks were small horseshoe tears or holes located anterior to the equator in 11/16 (69%) eyes. The retina of 12/16 (75%) eyes remained successfully reattached after a follow-up ranging from 4 to 132 months. All 12 eyes had visual acuity of 20/300 or better (range, 20/30-20/300). Eight of these eyes had visual acuity of 20/125 or better. The cause of failure in the remaining four eyes was proliferative vitreoretinopathy. CONCLUSIONS: Results of surgical repair of retinal detachment in Marfan's syndrome were better than previously thought. Bilaterality of detachment is extremely high, which justifies considering prophylactic treatment of the fellow eye in these patients.

Recalcitrant malignant glaucoma following pars plana vitrectomy, scleral buckle, and extracapsular cataract extraction with posterior chamber intraocular lens implantation.

Pars plana vitrectomy is employed to treat cases of aqueous misdirection that are refractory to medical and laser treatment. The authors describe a 65-year-old man without previous aqueous misdirection in whom this condition developed after a procedure that included pars plana vitrectomy. The aqueous misdirection recurred despite multiple interventions, including medical treatment, transiently successful Nd:YAG laser capsulo-hyaloidotomy, and surgical disruption of the anterior hyaloid face. It finally resolved after repeated pars plana vitrectomy with hyaloido-capsulo-iridectomy. There has been no recurrence 7 months after this procedure. The authors conclude that the surgical treatment of aqueous misdirection refractory to more conservative measures should include adequate disruption of the anterior hyaloid to prevent recurrence.

Retinal detachment associated with type III retinoblastoma regression after cryotherapy and external-beam radiotherapy.

PURPOSE: To report a child with rhegmatogenous retinal detachment originating from a focus of type III retinoblastoma regression after cryotherapy and external-beam radiation therapy. METHOD: Retinal detachment and multiple retinal holes, which were closely associated with the calcified mass of the regressed retinoblastoma, were treated with cryotherapy and scleral buckle. RESULTS: Positioning the regressed tumor and the retinal holes on the scleral buckle closed the holes. Subretinal fluid gradually reabsorbed after surgery, and complete retinal reattachment resulted. CONCLUSION: Rhegmatogenous retinal detachment is rare in patients with retinoblastoma, and scleral buckle can successfully manage such cases. In our patient, the detachment probably resulted from retinal necrosis secondary to cryotherapy and external-beam radiation therapy.

Presentation of retinoblastoma as phthisis bulbi.

PURPOSE: We sought to determine the incidence of retinoblastoma patients who presented with phthisis bulbi. METHODS: The medical records of 272 patients in the King Khaled Eye Specialist Hospital Retinoblastoma Registry were retrospectively studied. Clinical records, radiological investigations and histopathological slides were reviewed. RESULTS: We found that 2.7% of patients had retinoblastoma coincident with phthisis bulbi. Five of 10 patients had bilateral retinoblastoma; in the others it was unilateral. Radiologically, intraocular calcification was present in all except one case. All enucleated phthisical globes had residual viable tumour cells; optic nerve extension was found in 2 patients who had long-standing phthisis bulbi. CONCLUSION: Phthisis bulbi is an uncommon presenting sign of retinoblastoma which often occurs after an ocular inflammatory episode possibly related to intraocular tumour infarction. In most cases the tumour is not visible because of intraocular disruption. That every enucleated eye in this series harboured well-differentiated tumour cells underlies the seriousness with which phthisis bulbi of unknown origin in children should be investigated for retinoblastoma.