Bilateral sequential photodynamic therapy for sub-retinal neovascularization with type 2A parafoveal telangiectasis

Encapsulated cell technology: Delivering cytokines to treat posterior ocular diseases

Encapsulated cell technology (ECT) is a targeted delivery method that uses the genetically engineered cells in semipermeable polymer capsules to deliver cytokines. Thus far, ECT has been extensively utilized in pharmacologic research, and shows enormous potentials in the treatment of posterior segment diseases. Due to the biological barriers within the eyeball, it is difficult to attain effective therapeutic concentration in the posterior segment through topical administration of drug molecules. Encouragingly, therapeutic cytokines provided by ECT can cross these biological barriers and achieve sustained release at the desired location. The encapsulation system uses permeable materials that allow growth factors and cytokines to diffuse efficiently into retinal tissue. Moreover, the ECT based treatment can be terminated timely when we need to retrieve the implant, which makes the therapy reversible and provides a safer alternative for intraocular gene therapy. Meanwhile, we also place special emphasis on optimizing encapsulation materials and enhancing preservation techniques to achieve the stable release of growth factors and cytokines in the eyeball. This technology holds great promise for the treatment of patients with dry AMD, RP, glaucoma and MacTel. These findings would enrich our understandings of ECT and promote its future applications in treatment of degenerative retinopathy. This review comprises articles evaluating the exactness of artificial intelligence-based formulas published from 2000 to March 2024. The papers were identified by a literature search of various databases (PubMed/MEDLINE, Google Scholar, Cochrane Library and Web of Science).

SINGLE-SESSION BILATERAL REDUCED-SETTINGS PHOTODYNAMIC THERAPY FOR BILATERAL CHRONIC CENTRAL SEROUS CHORIORETINOPATHY

PURPOSE

We performed a multicenter, retrospective study on patients with bilateral chronic central serous chorioretinopathy (cCSC) who received single-session bilateral reduced-settings photodynamic therapy (ssbPDT) and assessed anatomical (resolution of subretinal fluid [SRF]) and functional (best-corrected visual acuity [BCVA]) outcomes and safety.

METHODS

Patients who underwent ssbPDT between 01/01/2011 and 30/09/2022 were included. The resolution of SRF at first, second, and final follow-up was assessed on optical coherence tomography (OCT), and BCVA measurements were collected at these visits. When fovea-involving ssbPDT was performed, ellipsoid zone (EZ) and external limiting membrane (ELM) integrity was graded before and after treatment.

RESULTS

Fifty-five patients were included in this study. Sixty-two of hundred and eight eyes (56%) showed a complete resolution of SRF at the first follow-up, which increased to 73/110 (66%) at the final follow-up. The mean logMAR BCVA improved by -0.047 ( P = 0.02) over follow-up. EZ integrity increased from 14/21 (67%) to 24/30 (80%) while ELM integrity increased from 22/30 (73%) to 29/30 (97%).

CONCLUSION

Patients with cCSC with bilateral SRF at baseline showed significant anatomical and functional improvements after ssbPDT, both at short-term and long-term follow-up. No relevant adverse events were noted.

FUNCTIONAL AND STRUCTURAL EFFECTS OF NONDAMAGING RETINAL LASER THERAPY FOR MACULAR TELANGIECTASIA TYPE 2: A Randomized Sham-Controlled Clinical Trial

PURPOSE

Macular telangiectasia (MacTel) Type 2 is a progressing neurovascular disease of the macula, currently lacking effective treatment. This study assessed the effect of nondamaging retinal laser therapy (NRT) compared with sham.

METHODS

Twelve MacTel patients were enrolled in this double-masked, controlled, randomized clinical trial. For the nine patients with both eyes eligible, one eye was randomized to NRT or sham and the other received alternate treatment. For three patients with only one eye eligible, that eye was randomly assigned either NRT or sham. Ellipsoid zone disruption, best-corrected visual acuity, and macular automated perimetry at 12 months served as structural and functional measures.

RESULTS

Eleven eyes were randomized to sham and 10 to NRT. Baseline best-corrected visual acuity was 66 letters (20/50) for sham and 72 letters (20/40) for NRT (P = 0.245). Ellipsoid zone disruption area was 298 µm2 in sham and 368 µm2 in NRT (P = 0.391). At 12 months, ellipsoid zone disruption increased by 24% in sham and decreased by 34% in NRT (P < 0.001). Best-corrected visual acuity measures remained stable during follow-up compared with baseline. At 1 year, the mean macular sensitivity was 28 dB in the NRT group, compared with 26 dB in sham.

CONCLUSION

Nondamaging retinal laser therapy was safe and well tolerated in patients with MacTel and resulted in structural and functional improvements, which could represent a protective effect of laser-induced hyperthermia. Longer follow-up and larger number of patients should help corroborate these effects.

Treatment Modalities for Idiopathic Macular Telangiectasia: An Evidence-Based Systematic Review of the Literature

PURPOSE

The purpose of this systematic review was to stratify the literature on the therapeutic approaches for macular telangiectasia (Mactel type 1 and 2) to provide evidenced-based practical guidelines for the optimal standard care of these conditions.

METHODS

A comprehensive search of PubMed was performed using a specific search algorithm. All articles retrieved were carefully screened and their references were manually reviewed for additional relevant data. Level of evidence was provided for each treatment modality, graded as level I, II, III, IV, and V, and indicative of very strong, strong, substantial, relatively weak, and weak evidence, respectively.

RESULTS

1445 abstracts were checked and 123 were found to be relevant. Out of them, 102 were eligible for the purpose of our review and 86 were focused on treatment of macular telangiectasia. Most publications combined cases of Mactel type 1 and type 2, despite their distinct pathophysiology. In Mactel type 1, laser photocoagulation of the telangiectasia remains the mainstay in controlling macular edema, while anti-vascular endothelial growth factor (anti-VEGF) agents provide short-term benefits. In Mactel type 2, current treatment options are not effective in the management of the non-proliferative stage, while anti-VEGF agents seem to be effective in the treatment of choroidal neovascularization complicating the disease.

CONCLUSION

It is important to differentiate the type of macular telangiectasia to plan appropriate treatment.

Ciliary neurotrophic factor for macular telangiectasia type 2: results from a phase 1 safety trial

PURPOSE

To evaluate the safety and tolerability of intraocular delivery of ciliary neurotrophic factor (CNTF) using an encapsulated cell implant for the treatment of macular telangiectasia type 2.

DESIGN

An open-label safety trial conducted in 2 centers enrolling 7 participants with macular telangiectasia type 2.

METHODS

The participant's more severely affected eye (worse baseline visual acuity) received the high-dose implant of CNTF. Patients were followed for a period of 36 months. The primary safety outcome was a change in the parameters of the electroretinogram (ERG). Secondary efficacy outcomes were changes in visual acuity, en face measurements of the optical coherence tomography of the disruption in the ellipsoid zone, and microperimetry when compared with baseline.

RESULTS

The ERG findings demonstrated a reduction in the amplitude of the scotopic b-wave in 4 participants 3 months after implantation (month 3). All parameters returned to baseline values by month 12 and remained so at month 36 with no clinical impact on dark adaptation. There was no change in visual acuity compared with baseline. The area of the defect as measured functionally by microperimetry and structurally by the en face OCT imaging of the ellipsoid zone loss appeared unchanged from baseline.

CONCLUSIONS

The intraocular delivery of CNTF in the encapsulated cell implant appeared to be safe and well tolerated in eyes with macular telangiectasia type 2. Further evaluation in a randomized controlled clinical trial is warranted to test for efficacy.

Macular telangiectasia type 2

Macular telangiectasia type 2 is a bilateral disease of unknown cause with characteristic alterations of the macular capillary network and neurosensory atrophy. Its prevalence may be underestimated and has recently been shown to be as high as 0.1% in persons 40 years and older. Biomicroscopy may show reduced retinal transparency, crystalline deposits, mildly ectatic capillaries, blunted venules, retinal pigment plaques, foveal atrophy, and neovascular complexes. Fluorescein angiography shows telangiectatic capillaries predominantly temporal to the foveola in the early phase and a diffuse hyperfluorescence in the late phase. High-resolution optical coherence tomography (OCT) may reveal disruption of the photoreceptor inner segment-outer segment border, hyporeflective cavities at the level of the inner or outer retina, and atrophy of the retina in later stages. Macular telangiectasia type 2 shows a unique depletion of the macular pigment in the central retina and recent therapeutic trials showed that such depleted areas cannot re-accumulate lutein and zeaxanthin after oral supplementation. There have been various therapeutic approaches with limited or no efficacy. Recent clinical trials with compounds that block vascular endothelial growth factor (VEGF) have established the role of VEGF in the pathophysiology of the disease, but have not shown significant efficacy, at least for the non-neovascular disease stages. Recent progress in structure-function correlation may help to develop surrogate outcome measures for future clinical trials. In this review article, we summarize the current knowledge on macular telangiectasia type 2, including the epidemiology, the genetics, the clinical findings, the staging and the differential diagnosis of the disease. Findings using retinal imaging are discussed, including fluorescein angiography, OCT, adaptive optics imaging, confocal scanning laser ophthalmoscopy, and fundus autofluorescence, as are the findings using visual function testing including visual acuity and fundus-controlled microperimetry. We provide an overview of the therapeutic approaches for both non-neovascular and neovascular disease stages and provide a perspective of future directions including animal models and potential therapeutic approaches.

Idiopathic juxtafoveolar retinal telangiectasis: a current review

Idiopathic juxtafoveolar retinal telangiectasis (IJFT), also known as parafoveal telangiectasis or idiopathic macular telangiectasia, refers to a heterogeneous group of well-recognized clinical entities characterized by telangiectatic alterations of the juxtafoveolar capillary network of one or both eyes, but which differ in appearance, presumed pathogenesis, and management strategies. Classically, three groups of IJFT are identified. Group I is unilateral easily visible telangiectasis occurring predominantly in males, and causing visual loss as a result of macular edema. Group II, the most common, is bilateral occurring in both middle-aged men and women, and presenting with telangiectasis that is more difficult to detect on biomicroscopy, but with characteristic and diagnostic angiographic and optical coherence tomography features. Vision loss is due to retinal atrophy, not exudation, and subretinal neovascularization is common. Group III is very rare characterized predominantly by progressive obliteration of the perifoveal capillary network, occurring usually in association with a medical or neurologic disease. This paper presents a current review of juxtafoveolar retinal telangiectasis, reviewing the classification of these entities and focusing primarily on the two most common types encountered in clinical practice, i.e., groups I and II, describing their clinical features, histopathology, natural history, complications, latest results from imaging modalities and functional studies, differential diagnosis, and treatment modalities.

Ocular photodynamic therapy--standard applications and new indications (part 1). Review of the literature and personal experience

Ocular photodynamic therapy (PDT) was introduced as a novel treatment for neovascular forms of age-related macular degeneration and choroidal neovascularization (CNV) secondary to pathologic myopia in the mid/end 1990s. The current treatment recommendations are based on the results of two large, prospective, multicenter, randomized clinical trials (Treatment of Age-Related Macular Degeneration with Photodynamic Therapy and Verteporfin in Photodynamic Therapy Studies) and thousands of patients have been treated worldwide over the last years. Meanwhile, PDT has been performed in several other ocular pathologies with some remarkable results, however, with most reports being case reports and small case series without statistical significance. These extended applications include CNV secondary to choroiditis and retinochoroiditis, angioid streaks, central serous chorioretinopathy, retinal angiomatous proliferation, parafoveal telangiectasia or CNV associated with macular dystrophy and idiopathic CNV, as well as diseases without CNV, such as choroidal hemangioma, retinal hamartoma, choroidal melanoma, chronic central serous chorioretinopathy, angiomatous lesions secondary to systemic diseases, rubeosis iridis or neovascular glaucoma. To date, with the introduction of anti-VEGF therapy, the role of PDT will certainly change. However, it is reasonable to believe that it will maintain an important role in combination therapy due to its unique properties of selective vascular targeting. Therefore, it is essential for the ophthalmologist to be familiar with the extended applications and their modifications of treatment parameters. This review will summarize the standard and experimental applications of PDT based on our own results and the literature.