Baseline characteristics of participants in the natural history study of macular telangiectasia (MacTel) MacTel Project Report No. 2

Right-angled vessels in macular telangiectasia type 2

PURPOSE

To evaluate the role of right-angled vessels (RAVs) during disease progression in macular telangiectasia type 2 (MacTel).

METHODS

In this study, 100 eyes of 52 patients and 52 eyes of 26 age-related controls were examined using fundus photography, spectral-domain optical coherence tomography (SD-OCT), OCT angiography (OCT-A) and fundus fluorescein angiography (FFA). Two masked readers graded fundus photographs of patients' eyes into five disease stages according to Gass and Blodi, and evaluated all eyes for the presence of RAVs. If RAVs were present, their course and origin (arterial vs venous) was evaluated with OCT-A and FFA, respectively. Additionally, we looked for morphological correlates of these vessels on SD-OCT scans. Neovascular eyes were analysed for the presence of RAVs and for morphological changes on formation of neovascularisations (NVs).

RESULTS

In OCT-A, RAVs were already detectable in eyes with early stages (1 to 2), could be tracked from superficial to outer retinal layers and were shown to form anastomoses in the outer retina with disease progression. These vessels were of both arterial and venous origin as shown by early phase FFA. Dilated capillaries and RAVs in OCT-A corresponded to hyper-reflective alterations of the outer retina on SD-OCT scans. In 19/19 eyes, NVs were associated with the presence of RAVs, and RAVs were shown to directly connect to neovascular complexes and to undergo morphological changes upon NV formation.

CONCLUSIONS

The results emphasise the role of RAVs during disease progression from an early stage on and demonstrate their involvement in the development of secondary NVs in MacTel.

Management of Idiopathic Macular Telangiectasia Type 2

Macular telangiectasia type 2 (MacTel) is a relatively rare disease without established treatments. Although MacTel was previously considered a primarily vascular condition, the thinking on its pathogenesis has shifted to it now being considered principally a neurodegenerative disease. This has resulted in a subsequent change in the approach to treatment toward neuro-protection for the non-proliferative phase of this disease. Carotenoid supplementation has had mixed results. Ciliary neurotrophic factor (CNTF) has demonstrated some promising early results, but further study is necessary to determine its actual effect. Some structural improvements have been seen in the non-proliferative phase with oral acetazolamide but without accompanying functional improvement. Anti-vascular endothelial drugs have been studied and not found to have benefit in the non-proliferative phase of disease but have demonstrated significant structural and functional value in the treatment of secondary neovascularization. There is no level I evidence for the various proposed MacTel treatments, and efforts need to be directed toward conducting multicenter randomized trials to better understand possible treatments for this condition.

Estimating Retinal Sensitivity Using Optical Coherence Tomography With Deep-Learning Algorithms in Macular Telangiectasia Type 2

IMPORTANCE

As currently used, microperimetry is a burdensome clinical testing modality for testing retinal sensitivity requiring long testing times and trained technicians.

OBJECTIVE

To create a deep-learning network that could directly estimate function from structure de novo to provide an en face high-resolution map of estimated retinal sensitivity.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional imaging study using data collected between January 1, 2016, and November 30, 2017, from the Natural History Observation and Registry of macular telangiectasia type 2 (MacTel) evaluated 38 participants with confirmed MacTel from 2 centers.

MAIN OUTCOMES AND MEASURES

Mean absolute error of estimated compared with observed retinal sensitivity. Observed retinal sensitivity was obtained with fundus-controlled perimetry (microperimetry). Estimates of retinal sensitivity were made with deep-learning models that learned on superpositions of high-resolution optical coherence tomography (OCT) scans and microperimetry results. Those predictions were used to create high-density en face sensitivity maps of the macula. Training, validation, and test sets were segregated at the patient level.

RESULTS

A total of 2499 microperimetry sensitivities were mapped onto 1708 OCT B-scans from 63 eyes of 38 patients (mean [SD] age, 74.3 [9.7] years; 15 men [39.5%]). The numbers of examples for our algorithm were 67 899 (103 053 after data augmentation) for training, 1695 for validation, and 1212 for testing. Mean absolute error results were 4.51 dB (95% CI, 4.36-4.65 dB) when using linear regression and 3.66 dB (95% CI, 3.53-3.78 dB) when using the LeNet model. Using a 49.9 million-variable deep-learning model, a mean absolute error of 3.36 dB (95% CI, 3.25-3.48 dB) of retinal sensitivity for validation and test was achieved. Correlation showed a high degree of agreement (Pearson correlation r = 0.78). By paired Wilcoxon rank sum test, our model significantly outperformed these 2 baseline models (P < .001).

CONCLUSIONS AND RELEVANCE

High-resolution en face maps of estimated retinal sensitivities were created in eyes with MacTel. The maps were of unequalled resolution compared with microperimetry and were able to correctly delineate functionally healthy and impaired retina. This model may be useful to monitor structural and functional disease progression and has potential as an objective surrogate outcome measure in investigational trials.

Macular Pigment Distribution as Prognostic Marker for Disease Progression in Macular Telangiectasia Type 2

PURPOSE

To evaluate macular pigment distribution pattern as a prognostic marker for disease progression in patients with macular telangiectasia type 2 (MacTel).

DESIGN

Retrospective cohort study.

METHODS

In this single-center study, 90 eyes of 47 patients were analyzed. Macular pigment optical density (MPOD) was measured with dual-wavelength fundus autofluorescence. Eyes were graded into MPOD distribution classes 1 to 3 with increasing loss of macular pigment and grading was performed masked by 2 independent graders. Best-corrected visual acuity, reading acuity, total scotoma size in fundus-controlled perimetry (microperimetry), and break of the ellipsoid zone (EZ) in optical coherence tomography (en face measurement) were defined as functional and morphologic outcome parameters and evaluated at baseline and after 60 months.

RESULTS

After a mean review period of 59.6 months (±standard deviation 5.2 months), no change between MPOD classes was observed compared to baseline. Morphologic and functional deficits were limited to the area of MPOD loss. At last follow-up, a significant mean decrease of visual acuity and reading acuity as well as a significant mean increase of scotoma size and EZ break were observed in eyes assigned to MPOD classes 2 and 3, while outcome parameters remained stable in eyes of class 1.

CONCLUSIONS

The results indicate that MPOD and its distribution may serve as a prognostic marker for disease progression and functional impairment in patients with MacTel.

Stereoscopic Vision in Macular Telangiectasia Type 2

PURPOSE

To investigate stereoscopic vision in patients with macular telangiectasia (MacTel) type 2 and correlate paracentral sensitivity loss to reduced stereoscopic function.

METHODS

In a prospective single-center study, 50 patients with MacTel type 2 and 25 age-matched controls were investigated. Stereoscopic function was evaluated with Lang I, Titmus, and TNO tests. Sensitivity of the central 16° was tested using fundus-controlled perimetry (microperimetry). Functional loss was quantified as depth, size, and localization of scotomata.

RESULTS

Both the Titmus and the TNO test revealed significantly reduced stereoscopic vision in patients compared to controls (p < 0.0001 for both). This applied even to patients with only relative or monocular paracentral scotoma. A strong correlation was observed for reduced stereoscopic vision with horizontal scotoma size and with the distance of scotomata from the foveal center.

CONCLUSIONS

The results indicate that stereoscopic vision is impaired early in patients with MacTel type 2. A paracentral sensitivity loss, even if mild and limited to one eye, may considerably interfere with stereoscopic function despite normal visual acuity. Projection of paracentral scotomata within the patient's central visual field plays an important role in stereoscopic vision and should be considered when interpreting stereoscopic test results.

Review of clinical approaches in fluorescence lifetime imaging ophthalmoscopy

Autofluorescence-based imaging techniques have become very important in the ophthalmological field. Being noninvasive and very sensitive, they are broadly used in clinical routines. Conventional autofluorescence intensity imaging is largely influenced by the strong fluorescence of lipofuscin, a fluorophore that can be found at the level of the retinal pigment epithelium. However, different endogenous retinal fluorophores can be altered in various diseases. Fluorescence lifetime imaging ophthalmoscopy (FLIO) is an imaging modality to investigate the autofluorescence of the human fundus in vivo. It expands the level of information, as an addition to investigating the fluorescence intensity, and autofluorescence lifetimes are captured. The Heidelberg Engineering Spectralis-based fluorescence lifetime imaging ophthalmoscope is used to investigate a 30-deg retinal field centered at the fovea. It detects FAF decays in short [498 to 560 nm, short spectral channel (SSC) and long (560 to 720 nm, long spectral channel (LSC)] spectral channels, the mean fluorescence lifetimes (τm) are calculated using bi- or triexponential approaches. These are meant to be relatively independent of the fluorophore's intensity; therefore, fluorophores with less intense fluorescence can be detected. As an example, FLIO detects the fluorescence of macular pigment, retinal carotenoids that help protect the human fundus from light damages. Furthermore, FLIO is able to detect changes related to various retinal diseases, such as age-related macular degeneration, albinism, Alzheimer's disease, diabetic retinopathy, macular telangiectasia type 2, retinitis pigmentosa, and Stargardt disease. Some of these changes can already be found in healthy eyes and may indicate a risk to developing such diseases. Other changes in already affected eyes seem to indicate disease progression. This review article focuses on providing detailed information on the clinical findings of FLIO. This technique detects not only structural changes at very early stages but also metabolic and disease-related alterations. Therefore, it is a very promising tool that might soon be used for early diagnostics.

No association between sleep apnoea and macular telangiectasia type 2 and its markers of severity and progression: a case-control study and retrospective cohort study

IMPORTANCE

Idiopathic Macular Telangiectasia Type 2 (MacTel) is an uncommon, progressive retinal disease usually affecting both eyes. Currently there is no know treatment however with similar comorbidities to Obstructive Sleep Apnoea (OSA) there is plausibility of an association which may accelerate disease progression.

BACKGROUND

To identify an association between MacTel and OSA and whether OSA may result in increased disease progression.

DESIGN

Matched case-control study and retrospective cohort analysis.

PARTICIPANTS

Fifty-seven patients with MacTel and 165 matched controls from the Busselton Health Study.

METHODS

MacTel participants were matched based on age, gender and body mass index (BMI) (and where possible hypertension and diabetes) on a 3:1 ratio with controls from the Busselton Health Study. Participants undertook a sleep questionnaire using a previously validated questionnaire. In a subset sleep apnoea severity was objectively measured via overnight ambulatory polygraphy (30 cases and 83 matched controls; ApneaLink device; ResMed, Sydney, Australia). In a retrospective analysis of the suspected MacTel cases we assessed whether major markers of OSA severity and MacTel progression were associated.

MAIN OUTCOME MEASURES

Apnoea Hypopnea Index along with key markers of MacTel progression.

RESULTS

MacTel patients did not have a higher risk of sleep apnoea when compared to age, sex and BMI -matched controls (mean ± SD Apnoea hypopnea index [AHI] cases 9.6 ± 14.7 vs. controls 9.7 ± 10.8, P = 0.95). No markers of disease progression in the cases were associated with any marker of OSA severity.

CONCLUSIONS AND RELEVANCE

Sleep apnoea does not increase the risk or accelerate the progression of MacTel.

Fluorescence Lifetime Imaging Ophthalmoscopy: A Novel Way to Assess Macular Telangiectasia Type 2

PURPOSE

Macular Telangiectasia Type 2 (MacTel) is an uncommon, late-onset complex retinal disease that leads to central vision loss. No causative gene(s) have been identified so far, resulting in a challenging clinical diagnostic dilemma because retinal changes of early stages are often subtle. The objective of this study was to investigate the benefit of fluorescence lifetime imaging ophthalmoscopy (FLIO) for retinal imaging in patients with MacTel.

DESIGN

Cross-sectional study from a tertiary-care retinal referral practice.

SUBJECTS AND CONTROLS

42 eyes of 21 patients (mean age 60.5±13.3 years) with MacTel as well as an age-matched healthy control group (42 eyes of 25 subjects, mean age 60.8±13.4 years).

METHODS

A 30° retinal field centered at the fovea was investigated using FLIO. This camera is based on a Heidelberg Engineering Spectralis system. Fundus autofluorescence (FAF) decays were detected in short (498-560 nm, SSC) and long (560-720 nm, LSC) spectral channels. The mean fluorescence lifetime, τm, was calculated from a 3-exponential approximation of the FAF decays. For MacTel patients, macular pigment (MP), OCT, blue light reflectance, fluorescein angiography, as well as fundus photography, were also recorded.

MAIN OUTCOME MEASURES

Mean FAF lifetime (τm) images.

RESULTS

FLIO of MacTel patients shows a unique pattern of prolonged τm at the temporal side of the fovea in patients with MacTel in the "MacTel area" within 5-6° of the foveal center. In early stages, this region appears crescent-shaped, while advanced stages show a ring-like pattern. This pattern corresponds well with other imaging modalities and gives an especially high contrast of the affected region even in minimally affected individuals. Additionally, FLIO provides a novel means to monitor the abnormal MP distribution. In one case, FLIO showed changes suggestive of MacTel within a clinically normal parent of two MacTel patients.

CONCLUSIONS

FLIO detects retinal changes in patients with MacTel with high contrast, presenting a distinctive signature that is a characteristic finding of the disease. The non-invasive properties of this novel imaging modality provide a valuable addition to clinical assessment of early changes in the disease that could lead to more accurate diagnosis of MacTel.

ABNORMAL RETINAL REFLECTIVITY TO SHORT-WAVELENGTH LIGHT IN TYPE 2 IDIOPATHIC MACULAR TELANGIECTASIA

PURPOSE

Macular telangiectasia Type 2 (MacTel) is a bilateral, progressive, potentially blinding retinal disease characterized by vascular and neurodegenerative signs, including an increased parafoveal reflectivity to blue light. Our aim was to investigate the relationship of this sign with other signs of macular telangiectasia Type 2 in multiple imaging modalities.

METHODS

Participants were selected from the MacTel Type 2 study, based on a confirmed diagnosis and the availability of images. The extent of signs in blue-light reflectance, fluorescein angiographic, optical coherence tomographic, and single- and dual-wavelength autofluorescence images were analyzed.

RESULTS

A well-defined abnormality of the perifovea is demonstrated by dual-wavelength autofluorescence and blue-light reflectance in early disease. The agreement in area size of the abnormalities in dual-wavelength autofluorescence and in blue-light reflectance images was excellent: for right eyes: ρ = 0.917 (P < 0.0001, 95% confidence interval 0.855-0.954, n = 46) and for left eyes: ρ = 0.952 (P < 0.0001, 95% confidence interval 0.916-0.973, n = 49). Other changes are less extensive initially and expand later to occupy that area and do not extend beyond it.

CONCLUSION

Our findings indicate that abnormal metabolic handling of luteal pigment and physical changes giving rise to increased reflectance are widespread in the macula throughout the natural history of the disease, precede other changes, and are relevant to early diagnosis.

ELECTROPHYSIOLOGICAL CHARACTERIZATION OF MACULAR TELANGIECTASIA TYPE 2 AND STRUCTURE-FUNCTION CORRELATION

PURPOSE

To investigate the electrophysiological features of macular telangiectasia Type 2 and their relationship to structure as determined by optical coherence tomography imaging.

METHODS

Forty-two eyes from 21 patients enrolled in the Macular Telangiectasia Natural History Observation Study were reviewed. All patients had full-field and pattern electroretinography (ERG; PERG) with some patients additionally having multifocal electroretinography (mfERG; N = 15) or electrooculography (N = 12). Multiple linear regression modeling assessed the relationship between the ellipsoid zone break size on optical coherence tomography and the central mfERG response.

RESULTS

Full-field ERG and electrooculography were normal in all eyes. Six eyes (14%) from five patients had subnormal PERG P50 amplitudes. Twenty-two of 30 eyes (73%) had reduced central or paracentral stimulus on mfERG. There was a significant correlation between ellipsoid zone break size and both the P1 amplitude (R = 0.37, P = 0.002) and P1:N1 ratio (R = 0.32, P = 0.002) of the central response on mfERG.

CONCLUSION

The electrophysiological findings in macular telangiectasia Type 2 are those of localized central dysfunction and are consistent with the structural data available from imaging and histologic studies. The ellipsoid zone break size correlates with mfERG reduction. The reduced mfERG P1:N1 ratio is consistent with inner retinal dysfunction.

CHARACTERISTICS OF PIGMENTED LESIONS IN TYPE 2 IDIOPATHIC MACULAR TELANGIECTASIA

PURPOSE

Pigment in the midretina is a characteristic sign in Type 2 idiopathic macular telangiectasia (MacTel) and is considered to characterize the late stage of the disease. Our aim was to investigate its incidence, and relationship with risk factors for MacTel, including outer retinal vascularization and subretinal neovascular proliferation (SRNV).

METHODS

Pigment extent was measured in fundus autofluorescence images of 150 eyes of 75 MacTel probands, using the Region Finder tool of Heidelberg Eye Explorer. A linear mixed model was used to analyze the dynamics of pigment and its associations with other features of the phenotype. The relative incidence of pigment and of outer retinal outer retinal vascularization and SRNV was analyzed within the full MacTel Study cohort (1,244 probands).

RESULTS

Mean pigment area at baseline was 0.157 mm (range = 0-1.295 mm, SD = 0.228 mm, n = 101). Progression demonstrated a nonlinear pattern (P < 0.001) at an overall rate of 0.0177 mm/year and was associated with the initial plaque size and with SRNV. There was a strong correlation between fellow eyes (P ≤ 0.0001). In approximately 25% of all SRNV cases, SRNV may coincide with or precede pigment.

CONCLUSION

Our data may be useful for refining the current system for staging disease severity in MacTel.

Idiopathic macular telangiectasis type 2 and co-existent diabetic retinopathy

Background

To study the interaction between idiopathic macular telangiectasis type 2 (MacTel2) and coexistent diabetic retinopathy (DR) during long term follow up.

Methods

A retrospective chart review was done for all eyes with MacTel2 and DR with a minimum 2 years follow up. Eyes with other retinal disorders and poor quality imaging were excluded. Data collected included demographics, presenting visual acuity, systemic evaluation, treatments done, duration of follow up, and final visual outcomes.

Results

Out of 951 patients with MacTel2, 277 patients had diabetes. Out of 277 patients, 44 eyes of 22 patients had MacTel2 coexisting with DR. Twenty-eight eyes of 14 patients were included in this study. All cases of MacTel2 were bilateral with a preponderance of women (71.42%). Mean follow up was 93.07 ± 84.03 months with a mean random blood sugar level of 135.41 ± 45.47 mg% at presentation. Twenty-five (89.28%) eyes presented with mild non-proliferative diabetic retinopathy. Two (7.14%) eyes progressed in their DR staging from baseline. Stage III MacTel2 were noted in 11 (39.28)% eyes at baseline. None of these eyes progressed to stage V during follow up. Mean presenting logMAR BCVA was 0.214 ± 0.227 which dropped to 0.399 ± 0.301 at last visit (p = 0.0005). Diabetic macula edema (DME) was not noted in any eye till last follow up.

Conclusions

12.5% of eyes with MacTel2 in diabetic patients had coexistent DR. MacTel2 led to slowly progressive visual loss irrespective of the presence of DR.

Risk factors in patients with macular telangiectasia 2A in an Asian population: A case-control study

Purpose:

The aim of this study was to evaluate risk factors in patients with macular telangiectasia (MacTel) 2A in an Asian population. This was a hospital-based case–control study.

Methods:

We reviewed the case records of patients in our hospital, diagnosed as MacTel 2A over a 3-year period from April 2011 to March 2014. Controls were selected from patients seen in the hospital at the same time for visual defects after matching for age and sex. A multivariate logistic regression model was constructed using the variables that showed a statistically significant association (P < 0.05) with MacTel 2A in the univariate analysis.

Results:

The mean age of the patients with MacTel 2A was 58.63 years. A majority (76; 73.8%) of the patients were female. Of the patients with MacTel 2A, 61 (59.2%) patients had diabetes mellitus, and 50 (48.5%) revealed hypertension. Multivariate logistic regression analysis revealed the presence of diabetes mellitus to be the risk factor with the highest odds ratio (OR) of 5.7 followed by hypertension with an OR of 2.6. Binary logistic regression showed hypermetropia to have a greater risk factor compared to emmetropia, OR 2.64.

Conclusion:

Our case–control study revealed that MacTel 2A is significantly associated with systemic diseases. Diabetes mellitus was found to have the strongest association with MacTel 2A, showing a high OR of 5.7. Systemic hypertension followed by an OR of 2.6. Compared to emmetropia, hypermetropia was significantly associated with MacTel 2A. There could be a genetic link between the two. Determining risk factors draws us close to the goal of identifying the etiopathogenesis of MacTel 2A.

EFFECT OF DARK ADAPTATION AND BLEACHING ON BLUE LIGHT REFLECTANCE IMAGING IN MACULAR TELANGIECTASIA TYPE 2

PURPOSE

In patients with macular telangiectasia Type 2, blue light reflectance imaging reveals an oval, parafoveal area in the macula that has increased reflectance compared with its surrounding. Here, we examine how dark adaptation and photobleaching can affect the blue light reflectance imaging pattern.

METHODS

Prospective study of patients with macular telangiectasia enrolled in the MacTel Natural History Observation Study. After dark adaptation, a sequence of images was obtained with a confocal scanning laser ophthalmoscope at 488 nm. Change of reflectance patterns was analyzed over time.

RESULTS

Eighteen eyes from 16 patients were analyzed. Initially, increased reflectivity in the parafoveal area resulted in higher gray values compared with the paramacular surrounding on blue light reflectance imaging. The difference between parafoveal and paramacular reflectance intensity decreased steadily during imaging, from 17.7 gray-value units (95% confidence interval: 12.1-23.2) down to 2.8 (95% confidence interval: -0.8 to 6.5) after around 30 seconds, and recovered after 5 minutes of dark adaptation.

CONCLUSION

A bleaching effect was evident in our study. Understanding these changes is important for both diagnosis and assessment of blue light reflectance phenotype in patients with macular telangiectasia and could also provide further insights into the pathophysiology of this disease.

Multimodality imaging in macular telangiectasia 2: A clue to its pathogenesis

Macular telangiectasia type 2 also known as idiopathic perifoveal telangiectasia and juxtafoveolar retinal telangiectasis type 2A is an acquired bilateral neurodegenerative macular disease that manifests itself during the fifth or sixth decades of life. It is characterized by minimal dilatation of the parafoveal capillaries with graying of the retinal area involved, a lack of lipid exudation, right-angled retinal venules, refractile deposits in the superficial retina, hyperplasia of the retinal pigment epithelium, foveal atrophy, and subretinal neovascularization (SRNV). Our understanding of the disease has paralleled advances in multimodality imaging of the fundus. Optical coherence tomography (OCT) images typically demonstrate the presence of intraretinal hyporeflective spaces that are usually not related to retinal thickening or fluorescein leakage. The typical fluorescein angiographic (FA) finding is a deep intraretinal hyperfluorescent staining in the temporal parafoveal area. With time, the staining may involve the whole parafoveal area but does not extend to the center of the fovea. Long-term prognosis for central vision is poor, because of the development of SRNV or macular atrophy. Its pathogenesis remains unclear but multimodality imaging with FA, spectral domain OCT, adaptive optics, confocal blue reflectance and short wave fundus autofluorescence implicate Müller cells and macular pigment. Currently, there is no known treatment for this condition.

SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF NEOVASCULAR MACULAR TELANGIECTASIA TYPE 2

BACKGROUND/PURPOSE

To image subretinal neovascularization in proliferative macular telangiectasia Type 2 (MacTel2) using swept source optical coherence tomography based microangiography (OMAG).

METHODS

Patients with macular telangiectasia Type 2 were enrolled in a prospective, observational study known as the MacTel Project and evaluated using a high-speed 1,050 nm swept-source OCT prototype system. The OMAG algorithm generated en face flow images from three retinal layers, and the region bounded by the outer retina and Bruch membrane, the choriocapillaris, and the remaining choroidal vasculature. The en face OMAG images were compared with images from fluorescein angiography and indocyanine green angiography.

RESULTS

Three eyes with neovascular macular telangiectasia Type 2 were imaged. The neovascularization was best identified from the en face OMAG images that included a layer between the outer retinal boundary and Bruch membrane. Optical coherence tomography based microangiography images identified these abnormal vessels better than fluorescein angiography and were comparable to the images obtained using indocyanine green angiography. In all 3 cases, OMAG identified choroidal vessels communicating with the neovascularization, and these choroidal vessels were evident in the 2 cases with indocyanine green angiography imaging. In 1 case, monthly injections of bevacizumab reduced the microvascular complexity of the neovascularization, and the telangiectatic changes within the retinal microvasculature. In another case, less frequent bevacizumab therapy was associated with growth of the subretinal neovascular complex.

CONCLUSION

Optical coherence tomography based microangiography imaging provided detailed, depth-resolved information about subretinal neovascularization in macular telangiectasia Type 2 eyes demonstrating superiority to fluorescein angiography imaging, and similarities to indocyanine green angiography imaging for documenting the retinal microvascular changes, the size and extent of the neovascular complex, the communications between the neovascular complex and the choroidal circulation, and the response to monthly bevacizumab therapy.

Characteristics and quantification of vascular changes in macular telangiectasia type 2 on optical coherence tomography angiography

BACKGROUND

Macular telangiectasia type 2 (MacTel 2) is a bilateral idiopathic, rare neurodegenerative disease with alterations in the macular capillary network leading to vision loss and is the most common of three subtypes. Optical coherence tomography angiography (OCTA) is a non-invasive imaging modality which helps understand the complex pathological changes, and images the blood vessels across different layers based on their flow characteristics.

METHODS

A cross-sectional study was conducted on 56 eyes of Asian Indian eyes of 28 consecutive patients with MacTel 2 studied during a 3-month period in a tertiary eye care hospital of South India. Clinically diagnosed cases of MacTel 2 underwent fundus photography, spectral domain OCT and OCTA. Fluorescein angiography was performed only when clinically indicated. Mean capillary density was calculated using a MATLAB-based automated software. The images were thresholded and binarised to derive the mean value.

RESULTS

The mean age at presentation was 60±5.2, with a female preponderance of 71.42%. Vascular network on OCTA shows an increase in the intervascular spaces with progressive capillary rarefaction and abnormal capillary anastomosis. The outer retina and choroid were involved during the later stages and showed a prominent vascular network. The mean capillary density of the superficial and deep layers was 39.99% and 39.03% as against 45.18% and 44.21% in the controls, respectively. There was a statistically significant difference between the two groups (p<0.01). There is a positive and statistically significant correlation between the superficial and deep layers.

CONCLUSION

OCTA helps understand the pathology and disease progression better in MacTel 2.

When is macular edema not macular edema? An update on macular telangiectasia type 2

Macular telangiectasia type 2 (Mac Tel 2) also known as idiopathic perifoveal telangiectasia and juxtafoveolar retinal telangiectasis type 2A is an enigmatic disease of unknown etiology. It manifests both neurodegenerative and vasculopathic characteristics.

It manifests itself during the fifth or sixth decades of life. Clinical characteristics include minimally dilated parafoveal capillaries with loss of the retinal transparency in the area involved, absence of lipid exudation, right-angled retinal venules, superficial retinal refractile deposits, hyperplasia of the retinal pigment epithelium (RPE), foveal atrophy and subretinal neovascularization (SRNV). Optical coherence tomography (OCT) images typically demonstrate outer retinal abnormalities and the presence of intra-retinal hyporeflective spaces that are usually not related with retinal thickening or fluorescein leakage. The typical fluorescein angiographic finding is a deep intraretinal hyperfluorescent staining in the temporal parafoveal area. With time this fluorescein hyperfluorescence involves the whole parafoveal area but does not extend to the center of the fovea. Long-term prognosis for central vision is poor, because of the development of SRNV or macular atrophy. Its pathogenesis remains unclear but multi-modality imaging with fluorescein angiography, spectral domain OCT, adaptive optics, confocal blue reflectance, short wave fundus autofluorescence, OCT angiography, and clinicopathological correlations implicate Müller cells. Currently there is no known treatment for this condition.

Vitreous humor in the pathologic scope: insights from proteomic approaches

The vitreous humor (VH) is the largest component of the eye. It is a colorless, gelatinous, highly hydrated matrix that fills the posterior segment of the eye between the lens and retina in vertebrates. In VH, a diversity of proteins that can influence retinal physiology is present, including growth factors, hormones, proteins with transporter activity, and enzymes. More importantly, the protein composition of VH has been described as being altered in a number of disease states. Therefore, attempts aiming at establishing a map of VH proteins and detecting putative biomarkers for ocular illness or protein fluctuations with putative physiologic significance were conducted over the last two decades, using proteomic approaches. Proteomic strategies often involve gel-based or LC techniques as sample fractioning approaches, subsequently coupled with MS procedures. This set of studies resulted in the proteomic characterization of a range of ocular disease samples, with particular incidence on diabetic retinopathy. However, practical therapeutic applications arising from these studies are scarce at the moment. A pertinent example of therapeutic targets arising from VH proteomics has emerged concerning vasoproliferative factors present in the vitreous, which should be involved in neovascularization and subsequent fibrovascular proliferation of the retina, in ocular disease context. Therefore, this review attempts to sum up the information acquired from the proteomic approaches to ocular disease conducted in VH samples, highlighting its clinical potential for disclosing ocular disease mechanisms and engendering pharmacological therapeutic treatments.

Adaptive optics microperimetry and OCT images show preserved function and recovery of cone visibility in macular telangiectasia type 2 retinal lesions

PURPOSE

To evaluate visual function and disease progression in the retinal structural abnormalities of three patients from two unrelated families with macular telangiectasia (MacTel) type 2.

METHODS

Adaptive optics scanning laser ophthalmoscopy (AOSLO) and AOSLO microperimetry (AOMP) were used to evaluate the structure and function of macular cones in three eyes with MacTel type 2. Cone spacing was estimated using histogram analysis of intercone distances, and registered spectral-domain optical coherence tomography (SD-OCT) scans were used to evaluate retinal anatomy. AOMP was used to assess visual sensitivity in and around areas of apparent cone loss.

RESULTS

Although overall lesion surface area increased, some initially affected regions subsequently showed clear, contiguous, and normally spaced cone mosaics with recovered photoreceptor inner/outer segment (IS/OS) reflectivity (two of two eyes). The AOMP test sites fell within three categories: normal-appearing cones (N), dimly reflecting cones (D), and RPE cell mosaics (R). At N sites, AOMP threshold values (arbitrary units [au]) increased with increasing eccentricity (slope = 0.054 au/degree, r(2) = 0.77). The N thresholds ranged from 0.04 to 0.27 au, D thresholds from 0.04 to 0.33 au, and R thresholds from 0.14 to 1.00 au. There was measurable visual sensitivity everywhere except areas without intact external limiting membrane (ELM) and with diffuse scattering in the IS/OS and posterior tips of the outer segments (PTOS) regions on OCT.

CONCLUSIONS

Visual sensitivity and recovery of cone visibility in areas of apparent focal cone loss suggests that MacTel type 2 lesions with a preserved ELM may contain functioning cones with abnormal scattering and/or waveguiding characteristics. (ClinicalTrials.gov number, NCT00254605.).

Meaning of visualizing retinal cone mosaic on adaptive optics images

PURPOSE

To explore the anatomic correlation of the retinal cone mosaic on adaptive optics images.

DESIGN

Retrospective nonconsecutive observational case series.

METHODS

A retrospective review of the multimodal imaging charts of 6 patients with focal alteration of the cone mosaic on adaptive optics was performed. Retinal diseases included acute posterior multifocal placoid pigment epitheliopathy (n = 1), hydroxychloroquine retinopathy (n = 1), and macular telangiectasia type 2 (n = 4). High-resolution retinal images were obtained using a flood-illumination adaptive optics camera. Images were recorded using standard imaging modalities: color and red-free fundus camera photography; infrared reflectance scanning laser ophthalmoscopy, fluorescein angiography, indocyanine green angiography, and spectral-domain optical coherence tomography (OCT) images.

RESULTS

On OCT, in the marginal zone of the lesions, a disappearance of the interdigitation zone was observed, while the ellipsoid zone was preserved. Image recording demonstrated that such attenuation of the interdigitation zone co-localized with the disappearance of the cone mosaic on adaptive optics images. In 1 case, the restoration of the interdigitation zone paralleled that of the cone mosaic after a 2-month follow-up.

CONCLUSION

Our results suggest that the interdigitation zone could contribute substantially to the reflectance of the cone photoreceptor mosaic. The absence of cones on adaptive optics images does not necessarily mean photoreceptor cell death.

Associations between autofluorescence abnormalities and visual acuity in idiopathic macular telangiectasia type 2: MacTel project report number 5

PURPOSE

The aim of this study was to determine whether typical abnormalities seen on autofluorescence (AF) imaging in patients with macular telangiectasia (MacTel) type 2 are correlated with visual acuity at presentation and with progression of visual loss over a 2-year follow-up period.

METHODS

A subgroup of 218 patients (413 eyes) enrolled in the MacTel study that underwent AF imaging was included in the present study. Images were graded at the Moorfields Eye Hospital Reading Center. Recorded AF abnormalities at baseline and at 2 years included the presence of increased AF because of loss of masking at the central macula, localized decreased AF at the end of a retinal vessel, and large area of decreased AF. Best-corrected visual acuity was measured using the Early Treatment for Diabetic Retinopathy chart at baseline and after 2 years. Statistical associations were sought by means of a generalized linear model.

RESULTS

Presence of increased macular AF (P = 0.004), a large area of decreased AF (P < 0.001), or decreased AF at the end of a retinal vessel (P < 0.001) at baseline were significantly associated with worse best-corrected visual acuity. Presence of increased macular AF (P < 0.001) or of localized decreased AF at the end of a retinal vessel (P < 0.001) and the absence of a large area of decreased AF (P < 0.001) were predictive of a subtle but significant drop in best-corrected visual acuity at 2 years.

CONCLUSIONS

Increased central AF at baseline heralds worse best-corrected visual acuity and predicts further subtle visual loss in a period of 2 years, which, however, does not stand out from the overall slowly progressive natural history of the disease.

First symptoms and their age of onset in macular telangiectasia type 2

PURPOSE

To investigate the first symptoms and their age of onset in a large cohort of patients with macular telangiectasia type 2.

METHODS

Patients with the characteristic findings of macular telangiectasia type 2 were interviewed. Data collection also included a chart review to determine the delay of the correct diagnosis and visual function 10 years after the onset of first symptoms.

RESULTS

Of 91 patients, 72 (79%) reported impaired reading ability as their first symptom, followed by metamorphopsia in 12%. The age of onset was most frequent (76%) in the sixth or seventh decade of life (50-69 years), and 58% of the patients were symptomatic before the age of 60 years. The median delay between first symptoms and the diagnosis of macular telangiectasia type 2 before the year 2005 was 7 years and has decreased to 1 year thereafter. Ten years after the onset of first symptoms, distance visual acuity of the better eye was ≥20/25 in 35% and ≤20/50 in 17%.

CONCLUSION

Impaired reading ability was the most common initial visual disturbance of patients with macular telangiectasia type 2, starting generally between the age of 50 and 70 years. Knowledge of the presenting symptoms of macular telangiectasia type 2 together with recently identified characteristic morphologic alterations on retinal imaging will likely lead to earlier accurate diagnosis of this disease entity.

Diagnosis of subretinal neovascularization associated with idiopathic juxtafoveal retinal telangiectasia - fluorescein angiography versus spectral-domain optical coherence tomography

BACKGROUND

To compare ability of fluorescein angiography (FFA) and spectral-domain optical coherence tomography (SD-OCT) to diagnose subretinal neovascularization (SRNV) secondary to idiopathic juxtafoveal retinal telangiectasia (IJRT) type 2A.

METHODS

Two masked observers evaluated FFA and SD-OCT images separately to diagnose the presence of SRNV in 65 eyes of 36 patients. A third masked observer diagnosed SRNV on color fundus photo. Presence of SRNV on color fundus photo was defined as presence of subretinal hemorrhage, thickening of retina, and/or visible membrane at the macula. Presence of SRNV on FFA was defined when there was hyperfluorescence in early phase with increase in intensity and size in the late phase; presence of membrane, large irregular lesion, hypofluorescence due to subretinal haemorrhage. SRNV on SD-OCT was defined as the presence of thickening of the retinal pigment epithelium-choriocapillaris complex with or without intraretinal fluid or subretinal fluid and associated with intraretinal hyperreflective area with retinal thickening.

RESULTS

Interobserver agreement (Kappa) for diagnosis of SRNV on FFA and SD-OCT was 0.373 (95 % CI, 0.106-0.617) and 0.775 (95 % CI, 0.612-0.899) respectively. The sensitivity and specificity of FFA were 52.3 % and 70.0 % respectively. With regard to SD-OCT, the sensitivity and specificity were 72.7 % and 64.1 % respectively in reference to color photograph. The negative predictive value (NPV) of SD-OCT (80.6 %) was higher than FFA (73.7 %). When we considered only the presence of subretinal hemorrhage on color photograph as a confirmed diagnosis of SRNV and compared the diagnostic ability of FFA and SD-OCT, we found that the FFA had poor sensitivity (58.3 %) but a better specificity (71.8 %) than SD-OCT, which had sensitivity of 75 % and specificity of 64 % (Tables 1 and 2). However, the negative predictive value (NPV) of SD-OCT (89.29 %) was slightly better than FFA (84.85 %).

CONCLUSION

Interobserver agreement between the observers was better for SD-OCT than for FFA in making the diagnosis of SRNV. SD-OCT is a better diagnostic modality than FFA for ruling out the presence of SRNV.

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.

The IS/OS junction layer in the natural history of type 2 idiopathic macular telangiectasia

PURPOSE

To document the progression of a break in the photoreceptor inner segment/outer segment (IS/OS) junction layer and its functional correlates over time in the natural history of type 2 idiopathic macular telangiectasia (type 2 MacTel).

METHODS

Patients with at least 1 year of follow-up were selected from the MacTel Study. En face images were created by manual segmentation of the IS/OS junctional line in volume scans acquired using a spatial-domain optical coherence tomography retinal imaging unit. Retinal sensitivity thresholds were determined using a retinal microperimeter unit. Aggregate retinal sensitivity loss within IS/OS lesions was calculated. Changes over time in an area of IS/OS defects and retinal sensitivity were analyzed.

RESULTS

thirty-nine eyes of 23 patients (mean age: 62.3 ± 9.2 years) were analyzed. Mean follow-up time was 1.9 years (range: 1-3 years). Mean IS/OS break area at baseline was 0.575 mm(2) (SE = 0.092, 95% confidence interval [CI]: 0.394-0.756 mm(2)). The cluster-adjusted mean annual progression rate in IS/OS break area was 0.140 mm(2) (SE = 0.040, 95% CI: 0.062-0.218 mm(2), P < 0.001). Mean aggregate retinal sensitivity loss was at baseline 28.56 dB (SE = 5.43, 95% CI: 17.32-39.80 dB, n = 28), a positive correlation with IS/OS lesion area was present (P < 0.001). The mean annual rate of change in aggregate sensitivity loss was 5.14 dB (SE = 1.51, 95% CI: 2.19-8.10 dB, P < 0.001, n = 37), a significant correlation with lesion area increase was found (P = 0.006).

CONCLUSIONS

Both IS/OS break area and rate of enlargement correlate with aggregate retinal sensitivity loss in type 2 MacTel. En face OCT imaging of the IS/OS layer provides a functionally relevant method for documenting disease progression in type 2 MacTel.

Multifocal electroretinography in type 2 idiopathic macular telangiectasia

BACKGROUND

To characterize the electroretinographic response of the macula by multifocal electroretinography (mfERG) in patients with type 2 idiopathic macular telangiectasia (MacTel).

METHODS

A prospective study of mfERG in patients with type 2 MacTel was conducted from April 2009 to November 2009. mfERGs were recorded using a visual evoked response imaging system (MonElec2, Metrovision, Perenchies, France). The International Society for Clinical Electrophysiology of Vision (ISCEV) guidelines were followed. Patients with type 2 MacTel confirmed by fundus fluorescein angiography without subretinal neovascularisation were included. For recording purposes, 61 stimulus hexagonal elements were used. The first-order kernel mfERG responses were analyzed. Individual mfERG responses for the hexagons were grouped into concentric rings centered on the fovea for analysis (< 2, 5-10, 10-15 and >15°). Student's t-test and Mann-Whitney U test and linear regression analysis was performed with STATA ver 11.1 (StataCorp, College Station , TX, USA).

RESULTS

Twenty eight eyes of 14 patients and 20 eyes of ten normal controls were included in the study. The mean logMAR visual acuity of the patients was 0.51 (Snellen equivalent 20/63). The mean N1 amplitude (nv/deg(2)) of patients were significantly reduced compared to controls and were as follows: 8.91 ± 14.00 vs 43.44 ± 9.55 (p < 0.0001) in less than 2°, 9.24 ± 10.47 vs 22.00 ± 3.87 (p < 0.0001) in 5-10°, 8.57 ± 10.02 vs 15.24 ± 1.89 (p < 0.0001) in 10-15°, and 7.03 ± 6.52 vs 12.47 ± 2.62 in > 15° (p < 0.001). The mean P1 amplitude (nv/deg(2)) was also significantly reduced in patients compared to controls and was as follows: 27.66 ± 37.44 vs 96.20 ± 12.41 (p < 0.0001) in less than 2°, 22.61 ± 19.38 vs 53.78 ± 9.79 (p < 0.0001) in 5-10°, 18.75 ± 20.21 vs 35.22 ± 4.16 (p < 0.001) in 10-15°, and 17.10 ± 12.54 vs 25.71 ± 3.93 (p < 0.001). The implicit time of N1 and P1 were also delayed significantly in all the rings. The mean central foveal thickness assessed by optical coherence tomography (OCT) scan was 84.78 ± 45.12 μm. There was poor correlation between mfERG amplitudes or implicit times with either the visual acuity or OCT central thickness.

CONCLUSION

mfERG showed significant reduction in amplitudes and implicit times of the waveforms in patients with type 2 MacTel in all the rings, suggesting a more generalized affection of the macula. The maximum reductions were seen in the <2(o) rings. Although there was poor correlation between the visual acuity and the amplitudes a of the waveforms, mfERG is a useful investigative modality for functional assessment of macula in type 2 MacTel patients.

Idiopathic macular telangiectasia type 2: the progressive vasculopathy

Purpose. To describe the complete sequence of the progressive vasculopathy in macular telangiectasia type 2.
Methods. This is a report of a case demonstrating the complete vasogenic sequence in macular telangiectasia type 2 over the course of 15 years, and representative images from a collective of 150 patients with macular telangiectasia type 2 employing fundus photography, fluorescein angiography, and optical coherence tomography.
Results. Macular telangiectasia may progress along a predictable vasogenic sequence which consists of nonproliferative stages, characterized by temporal loss of macular luteopigment and inner retinal volume loss in the absence of vascular changes, followed by a progressive proliferative vasculopathy, first involving the deep capillary plexus with eventual extension of the vascular changes circumferentially in the inner retinal capillary plexus. Late proliferative stages may become indistinguishable from advanced neovascular age-related macular degeneration.
Conclusions. While it is rare to observe the complete vasogenic sequence of macular telangiectasia type 2, a classification into nonproliferative and proliferative stages can be established, and may prove helpful as the mechanisms driving the pathogenic process through those stages are identified.

Prevalence and progression of pigment clumping associated with idiopathic macular telangiectasia type 2

PURPOSE

The purpose of this study was to investigate pigment clumping in idiopathic macular telangiectasia Type 2 for its incidence, development, and progression during the course of the disease.

METHODS

Patients with a diagnosis of idiopathic macular telangiectasia Type 2 and >12 months of follow-up were reviewed retrospectively. Measurements of the area of pigment clumping were performed and correlated with visual acuity and findings on spectral domain optical coherence tomography and microperimetry (MP-1).

RESULTS

Fifty-three eyes in 27 patients with a mean follow-up of 42.5 ± 14.2 months (range 12-79 months) were included. At study baseline, 16 eyes (30%) had evidence of pigment clumping without associated neovascular changes. During follow-up, 8 of 33 additional study eyes (24%) without previous pigment clumping developed it in Stage 3 (Gass-Blodi classification) disease. Pigment clumping increased in overall area as a function of follow-up time. Pigment clumping was associated with increased intraretinal reflectivity on optical coherence tomography and development of scotomas on microperimetry.

CONCLUSION

Pigment clumping commonly develops in Stage 3 idiopathic macular telangiectasia Type 2 disease, enlarges in area continuously over time, and is associated with declining visual function. Longitudinal measurements of the total area of pigment clumping may be helpful in following disease progression and may constitute a useful outcome measure for interventional clinical studies.

Ultrastructural and clinical evidence of subretinal debris accumulation in type 2 macular telangiectasia

Aims

To describe subretinal debris found on ultrastructural examination in an eye with macular telangiectasia (MacTel) type 2 and on optical coherence tomography (OCT) in a subset of patients with MacTel type 2.

Methods

Blocks from the mid-periphery and temporal perifovea of an eye with clinically documented MacTel type 2 were examined with electron microscopy (EM). Cases came from the Sydney centre of the MacTel project and the practices of the authors.

Results

On EM examination, subretinal debris was found in the perifovea with accumulation of degenerate photoreceptor elements in the subretinal space. Despite the substantial subretinal debris, there was minimal retinal pigment epithelial (RPE) reaction. Focal defects were seen in the inner limiting membrane in the perifovea. Of the 65 Sydney MacTel project participants, three (5%) had prominent yellow material at the fovea. OCT revealed smooth mounds between the RPE and the ellipsoid region. The material was hyperautofluorescent.

Conclusions

This study suggests that subretinal accumulation of photoreceptor debris may be a feature of MacTel type 2. Ultrastructural and OCT evidence of disease beyond the vasculature, involving photoreceptors and Muller cells, is presented.

Identification of a potential susceptibility locus for macular telangiectasia type 2

Macular Telangiectasia type 2 (MacTel) is a relatively rare macular disease of adult onset presenting with distortions in the visual field and leading to progressive loss of visual acuity. For the purpose of a gene mapping study, several pedigrees were ascertained with multiple affected family members. Seventeen families with a total of 71 individuals (including 45 affected or possibly affected) were recruited at clinical centers in 7 countries under the auspices of the MacTel Project. The disease inheritance was consistent with autosomal dominant segregation with reduced penetrance. Genome-wide linkage analysis was performed, followed by analysis of recombination breakpoints. Linkage analysis identified a single peak with multi-point LOD score of 3.45 on chromosome 1 at 1q41-42 under a dominant model. Recombination mapping defined a minimal candidate region of 15.6 Mb, from 214.32 (rs1579634; 219.96 cM) to 229.92 Mb (rs7542797; 235.07 cM), encompassing the 1q41-42 linkage peak. Sanger sequencing of the top 14 positional candidates genes under the linkage peak revealed no causal variants in these pedigrees.

Treatment of nonneovascular idiopathic macular telangiectasia type 2 with intravitreal ranibizumab: results of a phase II clinical trial

PURPOSE

To evaluate the safety and preliminary efficacy of intravitreal ranibizumab for nonneovascular idiopathic macular telangiectasia Type 2.

METHODS

Single-center, open-label Phase II clinical trial enrolling five participants with bilateral nonneovascular idiopathic macular telangiectasia Type 2. Intravitreal ranibizumab (0.5 mg) was administered every 4 weeks in the study eye for 12 months with the contralateral eye observed. Outcome measures included changes in best-corrected visual acuity, area of late-phase leakage on fluorescein angiography, and retinal thickness on optical coherence tomography.

RESULTS

The study treatment was well tolerated and associated with few adverse events. Change in best-corrected visual acuity at 12 months was not significantly different between treated study eyes (0.0 ± 7.5 letters) and control fellow eyes (+2.2 ± 1.9 letters). However, decreases in the area of late-phase fluorescein angiography leakage (-33 ± 20% for study eyes, +1 ± 8% for fellow eyes) and in optical coherence tomography central subfield retinal thickness (-11.7 ± 7.0% for study eyes and -2.9 ± 3.5% for fellow eyes) were greater in study eyes compared with fellow eyes.

CONCLUSION

Despite significant anatomical responses to treatment, functional improvement in visual acuity was not detected. Intravitreal ranibizumab administered monthly over a time course of 12 months is unlikely to provide a general and significant benefit to patients with nonneovascular idiopathic macular telangiectasia Type 2.

Impact of a low-vision self-management program on informal caregivers

PURPOSE

To evaluate caregivers' experiences and outcomes following attendance at a patient-centered group-based self-management program called "Living with Low Vision."

METHODS

Participants were caregivers of adults with low vision. A pre-post study design evaluated the impact of the program on single-item indicators that assessed levels of understanding of low vision, awareness of devices, aids and practical strategies, and questionnaires to assess confidence to deal with low vision, self-efficacy, and emotional well being. Participants formed three groups: (1) those who attended the program [intervention group 1 (IG1)] and received a take-home pack; (2) those who received a take-home pack only [intervention group 2 (IG2)]; and (3) those who received no intervention [comparison group (CG)].

RESULTS

Sixty participants (IG1 = 16, IG2 = 33, CG = 11) with mean (SD) age 67.2 years (SD = 14.8) were recruited. Half (n = 31; 51.7%) were the spouse of the adults with low vision. With the exception of two single-item indicators that assessed awareness of low-vision aids and practical strategies; no significant group differences on follow-up scores between the three study groups were found on any measure. Compared with CG participants, IG1 and IG2 participants demonstrated significantly greater awareness of low-vision aids and practical strategies (p < 0.05, for all). In addition, IG1 participants demonstrated significantly improved awareness of practical strategies than IG2 participants (p = 0.024). Most IG1 participants (n = 10; 62.5%) agreed that the program was relevant and helpful, and most would recommend it to other caregivers.

CONCLUSIONS

Involving caregivers in a patient-centered group-based self-management program and providing them with an informative take-home self-help pack improved their awareness of low-vision aids, devices, and practical strategies. Our findings should be followed up with larger studies to clearly identify optimal ways of providing caregivers with information and problem-solving skills to effectively manage the demands of low vision.

Intravitreal bevacizumab for treatment of proliferative and nonproliferative type 2 idiopathic macular telangiectasia

PURPOSE

To determine the effect of treatment with intravitreal bevacizumab on retinal thickness and visual acuity in the nonproliferative and proliferative forms of Type 2 idiopathic macular telangiectasia.

METHODS

Retrospective chart review of clinic patients treated with bevacizumab for macular telangiectasia Type 2. Treatment was performed until no further changes were seen after repeated bevacizumab injections. All patients had Snellen visual acuity testing, fundus fluorescein angiography, and measurement of central macular thickness by optical coherence tomography at baseline. Visual acuity and central macular thickness were recorded at follow-up visits.

RESULTS

Fourteen eyes of 10 patients were included. In 5 eyes with nonproliferative macular telangiectasia Type 2, average follow-up was 17 months (± 7 months), and no eye demonstrated improvement in visual acuity or decrease in central macular thickness at final follow-up compared with baseline. In 9 eyes with proliferative disease, follow-up averaged 17 months (± 9 months). At 6 weeks, central macular thickness decreased 63 μm (± 58 μm), and acuity improved 1.7 lines (± 2 lines). At final follow-up, central macular thickness decreased 48 μm (± 89 μm) and acuity improved 1.1 lines (± 3 lines). Subretinal neovascularization resolved in eight of nine eyes with proliferative disease after treatment.

CONCLUSION

Bevacizumab did not improve acuity or reduce retinal thickness in nonproliferative macular telangiectasia Type 2 at final follow-up. In proliferative macular telangiectasia Type 2, bevacizumab caused involution of neovascularization and improved visual acuity.