Retina Associates’ Case of the Month: September 2015

Raju LandR Full

Author: Jenny Ip

62 year old female with sudden vision loss

Case history

A 62 year old Indian female reported the sudden onset of blurred vision 2 weeks ago. She had undergone uneventful sequential bilateral cataract surgery 6 months previously, and recalls good vision post operatively. Co-existing medical conditions included hypertension and cholesterol, which were controlled on medication. Her family history was significant for blindness in her mother and glaucoma in her son.

Best corrected visual acuity was 6/9 in the right eye, and count fingers in the left eye. Intraocular pressures were 14mmHg OD and 10mmHg OS. Anterior exam showed intraocular lenses in good position, and clear ocular media. In the right eye, pigmentary changes, and crystalline deposits were present at the macula. In the left eye, there was multi-layered haemorrhage at the macula (See Figure 1).

What is your diagnosis?

Differential diagnosis

The differential diagnosis of macular haemorrhage includes choroidal neovascularisation due to neovascular age-related macular degeneration (including the subtype polypoidal choriodal vasculopathy), myopia and rarely adult vitelliform dystrophy, macular telangiectasia, and uveitis. Retinal vascular causes include macular branch vein occlusion and ruptured retinal macroaneurysm, though the former typically causes intraretinal rather than subretinal haemorrhage.

Additional investigations
Figure 2. Optical coherence topography showing right macula with loss of outer retinal layer and intraretinal hyporeflective cysts (a); and left macula showing hyperreflective lesion in the intraretinal and subretinal layers (b).

Figure 2. Optical coherence topography showing right macula with loss of outer retinal layer and intraretinal hyporeflective cysts (a); and left macula showing hyperreflective lesion in the intraretinal and subretinal layers (b).

Optical coherence topography (OCT) of the left macula shows a hyperreflective subretinal lesion and retinal fluid causing distortion of the retinal layers. In the right macula, there is disruption of the outer retinal layers, and intraretinal cysts (Figure 2).

Figure 3. Fluorescein angiogram of a) right eye with late hyperfluorescence in the area of retinal telangiectasia, and b) left eye with subretinal neovascularisation superior to the macula, and an area of hyperfluorescence in the temporal macula.

Figure 3. Fluorescein angiogram of a) right eye with late hyperfluorescence in the area of retinal telangiectasia, and b) left eye with subretinal neovascularisation superior to the macula, and an area of hyperfluorescence in the temporal macula.

Fundus fluorescein angiography confirms leakage subretinally in the left macula, there is also fluorescein leakage temporally in both maculae associated with telangiectasia (Figure 3). Indocyanine green imaging confirmed presence of a choroidal neovascular membrane (CNVM), but no polyps (Figure 4).

Figure 4. Indocyanine green of the left eye showing choroidal neovascularisation.

Figure 4. Indocyanine green of the left eye showing choroidal neovascularisation.

Diagnosis

The clinical signs and investigations are consistent with CNVM secondary to macular telangiectasia type 2.

Clinical course

The patient was commenced on treatment with intravitreal anti-VEGF therapy (aflibercept), with gradual improvement in vision in the left eye (most recent visual acuity 6/75, attained after 3 injections). Monitoring for subretinal neovascularisation continues for the right eye.

Discussion

Macular telangiectasia type 2 is a rare, typically bilateral condition characterised by perifoveal telangiectatic vessels, pigment clumping, crystalline deposits, reduced retinal transparency and foveal atrophy1,2. Fundus fluorescein angiography features include telangiectatic vessels usually in the temporal macula, with late hyperfluorescence. On OCT, hyporeflective cavities are usually located at the fovea pit within the inner retina.

Macular telangiectasia type 1 is far less common, identified by aneurysms and telangiectatic abnormalities, capillary non perfusion and lipid deposition1.

Both environmental and familial factors are thought to play a role in the pathogenesis of macular telangiectasia, though exact mechanisms are yet to be determined. One hypothesis is the loss of Muller cells, which in the healthy macula, provide support for the neurosensory retina and retinal vasculature.2

Vision loss in macular telangiectasia type 2 occurs predominantly due to foveal atrophy, and subretinal neovascularisation. Anti VEGF therapy may be effective in patients with subretinal neovascularisation3, but does not alter visual decline in patients without subretinal neovascularisation2,4. Currently, the use of ciliary neurotrophic factor (CNTF) is being investigated as potential treatment for macular telangiectasia5.

Take home points

 

Take home points
  • Macular telangiectasia is a rare cause of vision loss often with subtle clinical signs.
  • Careful clinical exam and the use of imaging modalities including fluorescein angiography and OCT are helpful in correctly identifying macular telangiectasia
  • Anti VEGF therapy may be useful in patients with subretinal neovascularisation

 

References
  1. Yannuzzi LA, Bardal AMC, Freund KB, Chen KJ, Eandi CM, Blodi B. Idiopathic Macular Telangiectasia. Arch Ophthalmol. 2006;124:450-460
  2. Issa PC, Gillies MC, Chew EY, Bird AC, Heeren TFC, Peto T, Holz FC, Scholl HPN. Macular telangiectasia type 2. Prog Retin Eye Res. 2013 May ; 34: 49–77
  3. Jorge R, Costa RA, Calucci D, Scott IU. Intravitreal bevacizumab (Avastin) associated with the regression of subretinal neovascularization in idiopathic juxtafoveolar retinal telangiectasis. Graefes Arch. Clin. Exp. Ophthalmol. 2006; 245:1045–1048
  4. Do DV, Bressler SB, Cassard SD , Gower EW, Tabandeh H, Jefferys J L, Bressler NM. Ranibizumab for macular telangiectasia Type 2 in the absence of subretinal neovascularisation. Retina 34:2063–2071, 2014
  5. Chew EY, Clemons TE, Peto T, Sallo FB, Ingerman A, Tao W, Singerman L, Schwartz SD, Peachey NS, Bird AC. Ciliary neurotrophic factor for macular telangiectasia type 2: results from a phase 1 safety trial. Am J Ophthalmol. 2015 Apr;159(4):659-666.