The Ophthalmology Department,  Universiti Malaysia Sarawak (UNIMAS), Kuching, Sarawak.

The Ophthalmology Department, Sarawak General Hospital, Kuching, Sarawak, East Malaysia.

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Case 39 Answers

by Professor Chua Chung Nen

 

A 60 year-old woman with bilateral pseudophakia and chronic open angle glaucoma decided to consult the eye department of Sarawak General Hospital after being under the care of a private ophthalmologist for the past 10 years. She was on latanoprost od, timolol 0.5% bd and trusopt bd to both eyes. The vision was 6/9 in both eyes with correction. Slit-lamp examination showed bilateral extracapsular cataract extraction and posterior intraocular lens implant via limbal incisions. The intraocular pressures (IOPs) were poorly controlled at 20mmHg right eye and 30 mmHg left eye. Fundoscopy showed cup disc ratio of 0.8 in both eyes. The visual fields showed bilateral arcuate scotoma being worse in the left eye. After two subsequent visits over two months in which the left IOP remained poorly controlled (28 mmHg and 29mmHg), she agreed to undergo left trabeculectomy with mitomycin C application.

 

There was no problems perioperatively except for a thin flap near the limbus because of scarring from the previous limbal incision. However, her vision dropped to hand movement the next day and slit-lamp examination revealed hyphaema (Figure 1) which appeared to arise from the iridectomy. The fundal view was poor. The anterior chamber was deep and the intraocular pressure was 6mmHg. She was reassured and discharged home with topical homatropine and garasone (gentamicin + betamethasone).

 

The hyphaema failed to resolve over the next seven days and the vision remained hand movement with poor fundal view. The patient was anxious and requested to have the blood evacuated.

 

Figure 1. Hyphaema arising from the iridectomy.

 

An anterior chamber wash-out was performed using Simcoe irrigation-aspiration cannula via a small corneal incision created using a keratome at one O'clock position. During the procedure, blood was noted behind the iris and behind the intraocular lens. The blood behind the iris was also aspirated.

 

Post-operatively, the anterior chamber was free of blood but the fundal view was hazy due to vitreous haemorrhage. Vitreous strand was present in the anterior chamber extending from the inferior pupil and became incarcerated in the corneal incision wound (Figure 2 and 3). The IOP was normal at 9mmHg. Ultrasound confirmed the presence of vitreous haemorrhage without signs of choroidal detachment (Figure 4). The patient was reassured that the vitreous haemorrhage will clear with time.

 

 

Figure 2. Vitreous in the anterior chamber arising from the inferior pupil.

 

Figure 3. Vitreous in the anterior chamber and blood can be seen behind the vitreous.

 

Figure 4. B-scan showing vitreous haemorrhage.

 

The patient returned 4 days later with a painful left eye. On examination, the vision remained hand movement and the left eye was severely injected. The intraocular pressure measured 60mmHg. She was treated with intravenous acetazolamide and topical timolol 0.5% bd which brought the IOP down to 38mmHg. Peripheral iridotomy was performed using both argon and YAG laser. The IOP was brought down to 18mmHg with only topical timolol 0.5% bd. However, the IOP increases to 38mmHg again four days later and the iridotomy was blocked by vitreous from behind the iris (Figure 5).

 

Figure 5. Iridotomy blocked by vitreous.

 

An anterior vitrectomy was performed to clear the anterior chamber and the pupil of vitreous (Figure 6). Post-operatively, the IOP rose to 28mmHg and required the combined use to timolol 0.5% bd and latanoprost od to bring it down to 18mmHg. The vision improved gradually over the next 4 weeks to 6/18 with spontaneous resolution of the vitreous haemorrhage.

 

Figure 6. Rounded pupil one week after anterior vitrectomy.

 

a. What may be responsible for the presence of vitreous haemorrhage in this patient?

 

There are two possible reasons for the vitreous haemorrhage:

 

i. Haemorrhage from iridectomy which tracked itself into the vitreal cavity because of a breach of the posterior capsule from previous extracapsular cataract and implant. This is the most likely reason from the course of event. The previous cataract operation was complicated by posterior capsular tear and the intraocular lens was implanted in the sulcus and therefore there was no barrier to the backward tracking of the blood.

 

ii. During the iridectomy, the ciliary body was inadvertently cut resulting in vitreous haemorrhage.

 

b. What is the cause of the high IOP following anterior chamber washout?

Pupillary block glaucoma from vitreous is the cause of the increased IOP. During the anterior chamber hyphaema washout, the vitreous behind the iris was disturbed and moved forward to block the pupil impairing the aqueous drainage. It is also possible her initial glaucoma may be the result of partial pupillary block from vitreous behind the iris as a result of the complicated cataract surgery.

 

c. What are the mistakes in the management of this patient?

There are several mistakes in the management of this patient:

 

1. Failure to obtain sufficient information before trabeculectomy.

It is tempting for an ophthalmologist to perform trabeculectomy when the IOP is not controlled with maximal medications. In this patient, the complete record was not obtained from the private ophthalmologist before embarking on surgery. Otherwise, the pupil would have been dilated and vitreous might have been noted behind the iris. This would have alerted the surgeon to possible complications such as bleeding into the vitroeus and blockage of the iridectomy and trabeculectomy by prolapsed vitreous. A more course of action would be to perform anterior vitrectomy before trabeculectomy.

 

2. Failure to perform B-scan before anterior chamber wash-out.

The decrease of vision in this patient is the result of hyphaema and vitreous haemorrhage. However, this was not appreciated before the anterior chamber wash-out because B-scan of the vitreous cavity was not performed. Otherwise, one may wait for spontaneous resolution of the haemorrhage and hence avoid the complication of pupillary block from vitreous as a result of the wash-out.

 

This case highlights the importance of obtaining a full history of any patient undergoing trabeculectomy (especially one who has had previous cataract surgery) to avoid unwanted complications.

 

References:

 

1. Kieler RA, Stambaugh JL. Pupillary block glaucoma following intra-ocular lens implantation. Ophthalmic Surg 1982;13:647-50.

 

2. Simel PJ. Posterior chamber implants without iridectomy. A m Intraocular Implant Soc J 1982;8:141-43. 

 

3. Van Buskirk EM. Pupillary block after intraocular lens implantation. Am J Ophthalmol 1983;95:55-59.