Photoessay

Use of the Neodymium-YAG laser to manage subinternal limiting membrane haemorrhage Peter Chau, MRCP(UK), FRACS, FRACO Joseph A. Reich, DO(Melb), FRACS, FRACO

A 24-year-old Sri Lankan woman presented with an eight-day history of sudden right visual loss. She was otherwise fit and healthy.

Visual acuities were right 1/36, left 6/5. A disc- shaped subinternal limiting membrane (ILM) haemorrhage was observed in the right eye overlying the fovea (Figure 1). A horizontal fluid level separated what was presumed to be erythrocytes below, and serum above. The fluid level was observed to move with eye motion. The glistening inner surface of the elevated ('detached') ILM was also observed to move with eye motion.

There was no history of trauma, Valsalva manoeuvre, diabetes or systemic hypertension. Investigations for a bleeding diathesis or haemato- logical abnormality were negative.

Two weeks later, her right visual acuity was 1/60 and there had been no appreciable change in her clinical appearance.

As the patient had recently emigrated to Australia and was due to attend an interview for employment by the Commonwealth Public Service, preceded by a medical examination, prompt restoration of vision was desired.

The use of the Neodymium-YAG laser to create a defect in the ILM elevated by haemorrhage has been previously reported. Gabel et al. documented three cases successfully treated using powers ranging from 3.6 to 50.0 millijoules.' Their metho- dology was otherwise not described. One of the

From The Royal Victorian Eye and Ear Hospiral, Melbourne

current authors had previous experience with two similar cases with successful outcomes.

In choosing the site of application of laser, consideration was given to draining the most dependent fluid, while staying the maximum anteroposterior distance away from the underlying retina. One also tried to stay away from the antici- pated underlying continuation of the inferotemporal retinal vein and artery.

Pretreatment with Argon blueigreen laser was given using a Mainster lens (200 microns x 0.20 seconds x 0.19 watt). As the power was gradually increased to 0.19 watt, blanching was accompanied by visible contraction of the ILM.

A Goldman lens was used for YAG laser (Cooper Vision 2500). Single pulses of 6.4 millijoules were given and perforation occurred on the eleventh pulse. There was an immediate movement of blood from the sub-ILM space into the vitreous cavity. The photograph taken 30 minutes after laser treatment shows that more than half of the sub-ILM blood has moved out into the vitreous cavity (Figure

Five days later, her right visual acuity had improved to 6/18. Five weeks after laser treatment her right visual acuity was 615 and there was no residual sub-ILM blood, only the faint circular outline of her previous ILM detachment (Figure 3). The site of laser application was indicated by subtle ripples in the now reattached ILM radiating out from the site of perforation. No underlying retinal damage was observed. Organising vitreous

2).

Reprinr requests: Dr P. Chau, 688 Whitehorse Road, Mont Albert, Victoria 3127, Australia

Use of the Neodynium-YAG laser to manage subinternal limiting membrane haemorrhage 81

Fig. 4. -Fluorescein angiogram five weeks after laser treatment. Fig. 1. - Subinternal limiting membrane haemorrhage with fluid

level. Visual acuity was 1/36.

haemorrhage was seen inferiorly. T h e patient was asymptomatic.

A follow-up fluorescein angiogram was normal apart from a thin inferior crescent of partially blocked fluorescence due to overlying haemosiderin (Figure 4).

Discussion T h e cause of this woman’s sub-ILM haemorrhage is unknown. A detached posterior vitreous face was not observed at any stage, and so it is presumed that all of the haemorrhage moved into the vitreous gel.

Most of the available models of YAG laser are designed for use in the anterior segment where oblique slit-lamp illumination is desirable. Illumi- nation cannot be made coaxial with the laser aiming beam as the illumination arm blocks the aiming beam. This is a distinct disadvantage in the posterior segment, where oblique illumination is restricted by the size of the pupil and further restricted by the aperture of the posterior segment contact lens. Many YAG laser delivery slit lamps have only one fixed magnification, which in the posterior segment gives a very limited field of view and difficulty with orientation.

In this patient, with the illumination beam slightly off axis, visualisation was sufficient to proceed. Were it not for the preplaced Argon blanch, orientation would have been impossible because of excessive magnification and reduced field and application of YAG laser would have been dangerous.

The creation of a defect in the I L M elevated by haemorrhage with a YAG laser can be a useful,

Fig. 2.-Appearance 30 minutes after argonNAG laser treatment.

Fig. 3.-Appearance five weeks after laser treatment. Visual acuity improved to 615.

a2 Australian and New Zealand Journal of Ophthalmology 1991. 19(1)

effective and safe procedure. It could be made even safer with an improved YAG laser delivery system and would obviate the need for Argon pretreatment. Its application in proliferative diabetic retinopathy, a common cause of sub-ILM haemorrhage, where there is often a complex relationship between the ILM, posterior vitreous face and vitreous gel due to fibrovascular proliferation, needs further exploration.

Acknowledgements Prue Hanley and Glenis Grant for photographic work.

Reference 1. Gabel VP, Birngruber R, Gunther-Koszka H, Puliafito CA.

Nd: YAG laser photodisruption of hemorrhagic detachment of the internal limiting membrane. Am J Ophthalmol 1989; 107:33-37.

Use of the Neodynium-YAG laser to manage subinternal limiting membrane haemorrhage 83