Retinal arterial macroaneurysms are a well defined retinal vascular disorder consisting of saccular or fusiform dilatations (100-250 μ) of major retinal arterioles, usually within the first three orders of bifurcation. They commonly occur in elderly, hypertensive women along the superotemporal or inferotemporal arcades. Their natural history is often benign, with many progressing to spontaneous fibrosis and involution with retention of good vision. However, the visual acuity may decrease as a result of macular haemorrhage, oedema, exudates or serous detachment. Rupture of these aneurysms often results in collection of subretinal and subhyaloid blood with typical ’hour-glass’ appearance and causes sudden severe visual loss. In a patient who presents with subretinal or subhyaloid haemorrhage, the diagnosis of an underlying retinal arterial macroaneurysm may be difficult. We report one such case with a typical ’hourglass’ haemorrhage treated by argon laser hyaloidotomy that not only improved the vision but also helped us identify and treat the underlying macroaneurysm.
A 68-year old male presented to us with a two-day history of sudden onset of reduction of vision in the right eye following a violent bout of sneezing. There was no history of contributing systemic illness such as hypertension and cardiovascular disease. Snellen visual acuity was 1/60 in right eye and 6/6 in the left eye. On indirect ophthalmoscopy and 90D slitlamp biomicroscopy a subhyaloid haemorrhage approximately 3 x 2 disc diameter in dimension in the premacular region, accompanied by a subretinal haemorrhage along its inferotemporal border [Figure - 1] was seen. Systemic investigations did not contribute to detect ing the cause of subhyaloid haemorrhage.
On the 8th day of presentation (10th day of symptom), the patient underwent argon laser hyaloidotomy for drainage of subhyaloid haemorrhage. This treatment was aimed at achieving early visual rehabilitation (due to occupational reasons) and to confirm whether or not the subretinal bleed was extending into the foveal region. Analogous to the ’stretch-burn’ technique of argon laser iridotomy, three shots of 400 mW power, 100 μ spot size and 0.1 second duration were aimed at the most dependent portion of the dome-shaped elevation of subhyaloid haemorrhage. This was followed by a 600 mW central shot of 50μ spot size and 0.1 second duration. However, when the drainage failed, a similar procedure was repeated at a point Z\v disc diameter nasal to the above site. Following this, the subhyaloid haemorrhage drained out and the vision improved to 6/12 [Figure - 2].
At the end of 15 days of follow-up (a week after hyaloidotomy) fundus examination showed a retinal arterial macroaneurysm along the inferotemporal arcade [Figure:3a]. This was confirmed by fluorescein angiography, which showed a diffusely leaking macroaneurysm. There was no damage to the surrounding retina corresponding to the laser drainage site [Figure:3b]. On the same day, additional argon laser treatment - 15 confluent burns to the perianeurysmal area and 5 burns directly over the aneurysm (100 mW power, 100 μ spot size and 0.1 second duration) - were given (Figure 4), with blanching of the macroaneurysm as the end point. Following laser photocoagulation there was no bleeding or any other resultant complication. The final visual acuity of the patient was 6/9 at the end of another month.
Retinal macroaneurysms are a ’masquerade syndrome’ especially when the true nature of the pathological condition is obscured by preretinal, intraretinal or vitreous haemorrhage. They can mimic a myriad of clinical conditions ranging from age-related macular degeneration to a choroidal melanoma. A dense premacular haemorrhage may occur from proliferative diabetic retinopathy, a ruptured retinal arterial macroaneurysm or Valsalva retinopathy. Spontaneous clearing without any sequelae is common in a case of Valsalva retinopathy.
Early vitrectomy could be a definite treatment for subhyaloid haemorrhage; laser drainage procedure is an effective alternative procedure. Besides helping in immediate improvement of vision, laser drainage helps unmask the underlying pathology.
Although Nd:YAG laser has been advocated for the drainage of premacular haemorrhage, we found that argon laser is superior and possibly safer. Argon laser focuses better on the retinal tissue, is absorbed less by ocular media and avoids damage to the surrounding retina. However, one should keep in mind the potential disadvantages of posterior hyaloidotomy such as slower drainage of the intravitreal blood, chances of choroidal and retinal injury, possibility of transvitreal membrane formation by cells escaping into the vitreous and subsequent development of retinal detachment.
This case was unique in the sense that, to our knowledge there has been only one report in the literature that quotes the use of argon laser for drainage of subhyaloid haemorrhage. However, it requires a long-term study to ascertain the above advantages and to decide on the parameters to be used for this procedure.
It is stated that once ruptured, macroaneuryms rarely rebleed. But, in presence of fluorescein dye leakage threatening the fovea, immediate treatment to obliterate the macroaneurysm is warranted. Direct and perianeurysmal laser treatment is considered a safe and definitive method of closure in such cases.
A high index of suspicion, prompt diagnosis and intervention may help restore vision in ruptured retinal arterial macroaneurysm masked by a subhyaloid haemorrhage.
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