Dear Editor

We read with interest the letter by Prakash et al.[1] concerning residual cortical lens matter in the anterior chamber after phacoemulsification. This was noted ten days post-operatively and was promptly removed to alleviate a secondary rise in intraocular pressure (IOP). We would like to share our experience of an unusual case of retained lens matter presenting thirteen months post phacoemulsification.

A 77-year old male patient presented with slight blurring of vision and photophobia in the right eye, thirteen months after undergoing uncomplicated phacoemulsification with posterior chamber intraocular lens implantation (Acrysof SA60). His visual acuity was 6/12 in this right eye and he had 1+ cells in the anterior chamber with no evidence of synechiae and a normal IOP. Posterior segment examination was unremarkable. A presumptive diagnosis of recurrent post-operative uveitis was made and he was treated with a course of topical corticosteroids. However, at his follow up visit three weeks later, his condition had not improved. Examination now revealed corneal oedema localized inferiorly and a small piece of residual nuclear lens matter was now evident in the anterior chamber, which had not been noted initially. This fragment of 1 mm by 1mm in size was seen lodged between the inferior iris and the cornea. A day later it was surgically removed under topical anaesthesia. Two weeks later the visual acuity had improved to 6/9 and the corneal oedema as well as the anterior chamber activity had resolved completely.

Retained nuclear or cortical lens matter after phacoemulsification tends to present in the first few weeks following surgery and can cause a more pronounced uveitis, corneal oedema, intraocular pressure rise and/or cystoid macula oedema.[2] However, presentation although rare has been reported as late as 5 months postoperatively.[3] To our knowledge, this is the first case to present with this specific complication 13 months postoperatively. We presume the mechanism to be initial entrapment of the residual lens matter in the ciliary sulcus at a very peripheral location. This would be followed by gradual migration of the fragment towards the pupil facilitated by iris contraction/dilation movements and eventually into the anterior chamber giving rise to symptoms. Meticulous technique and a careful survey for any retained lens material at the time of surgery is essential in preventing such complications. One must also consider this possibility in post operative patients presenting with recurrent uveitis even many months after the initial operation.

References

1. Prakash G, Kumar A, Purohit A. Unusual case of residual cortical lens matter in anterior chamber. Br J Ophthalmol. 2003 Nov;87(11):1421.

2. Coombes A and Gartry D. Postoperative complications. In: Cataract Surgery 1st ed. BMJ, 2003:168,172.

3. Bohigian GM, Wexler SA.Complications of retained nuclear fragments in the anterior chamber after phacoemulsification with posterior chamber lens implant. Am J Ophthalmol. 1997 Apr;123(4):546-7.

We thank Drs Hanovar and Ali for their comments. The main impetus for publishing this data was to show that children are NOT prone to infections with this strategy. In fact while steroid injections were given in cases of severe corneal neovascularisation such as K.I.D. syndrome and ectodermal hypoplasia , the fact that no child got a canaliculitis or other infection even when steroids were used, re-affirms that infection is not a risk that should prevent the clinician from using silicone punctal plugs if appropriate. Furthermore , clinically if spontaneous extrusion occurred after 6 months we often found that the symptoms had improved. We really wanted to know if using the plugs was a redundant manouevre , hence discussing the rate of extrusion within 6 months of placement , which we considered to be high in any case ( 19%). Perhaps the most striking fact is that we were unable to cite any other article dedicated to children with respect to the use of punctal plugs . We hope this article will encourage Drs Ali and Hanovar and others to share their experiences.

Conflict of Interest:

None declared

Dear Editor

The authors of this article (Tan J C H, and Hitchings R. Non-penetrating glaucoma surgery: the state of play. Br J Ophthalmol 2001;85:234-237) should be commended on attempting to tackle this issue. Nevertheless we do feel that their fundamental points and principal arguments merit reconsideration.

The authors state categorically that "long term outcomes do not exit for the newer non-penetrating surgery technique" when in fact long term (43.2 months +/- 14.3 (SD)) results for deep sclerectomy with collagen implant have been presented to the European Glaucoma Society (EGS) Glaucoma Symposium, 2000, and have also been published some time ago.[1] The study provided a qualified success rate of 94.8% and the complete success rate, 61.9% after 60 months (survival analysis), with a mean IOP at end of follow-up of 11.8 +/- 3. The study reported no surgically induced cataract of the whole series of 105 patients.

The authors, unfortunately, failed to cite a landmark study[2] comparing deep sclerectomy without an implant to trabeculectomy in the two eyes of the same patient in a prospective randomised fashion. At 12 months, mean IOP reduction was 12.3 +/- 4.2 (sclerectomy) versus 14.1 +/- 6.4 mmHg (trabeculectomy) (P = 0.15), and an IOP Furthermore the authors cite a study by Gandolfi as personal communication supposedly providing evidence that "trabeculectomy produces lower and better sustained IOP control than either viscocanalostomy or deep sclerectomy". The authors fail to mention however, that in this particular study postoperative YAG goniopunctures were considered as a failure criteria. Excluding goniopuncture from the success criteria would easily be compared to considering laser suture lysis or even YAG capsulotomies to be failure criteria of glaucoma or cataract surgeries. Furthermore Gandolfi concluded that Deep sclerectomy was associated with lower perturbation of lens nuclear transparency (personal communication, January 2002).

In another point worthy of reconsideration the authors site a study [3] that allegedly draws attention to high rates of hypotony and hyphaema after intraoperative conversion of deep sclerectomy to trabeculectomy following accidental intraopeartive perforation of the trabeculo- Descemet's membrane (TDM). However the authors again fail to mention, when quoting this specific study, that "when deep sclerectomy is complicated with a perforation of the TDM, the long term success rate of the surgery is similar to that of trabeculectomy". This conclusion would encourage the surgeons to start their surgery as a deep sclerectomy, knowing that in case of a perforation and a subsequent transformation to trabeculectomy, the chances of success would be similar to initial trabeculectomy.

The authors of the paper at hand compare in their figures viscocanalostomy, deep scelerectomy without an implant, deep sclerectomy with collagen implant, and deep sclerectomy without suturing the superficial flap to each other, and thus drawing certain conclusions. The different techniques have one thing in common, the element of non- perforation. It is not useful to compare apples and pears.

A major factor in the conflicting, often contradictory, results available is the element of long learning curves. As an example one group reported 0% success rate in their first series of viscocanalostomy patients [4] and then presented their second series with a success rate of 15%.[5]

The same group also analyzed the depth of their dissection of the deep sclera [6] to find that they dissected too superficially in 48% of their cases and too deeply in 17%. Meaning that the proper depth of dissection, which should bisect transversally the Schlemm's canal deroofing it, was not achieved in the majority of their cases.

To achieve successful non-penetrating surgery, the dissection of the deep sclerectomy needs to be correct. This entails a total excision of corneal stroma behind Descemet's membrane and the excision of the inner wall of Schlemm's canal and the juxtacanalicular trabeculum. An implant has to be used to maintain the scleral space patent.[7] Laser goniopuncture should be performed at any postoperative stage when IOP mounts beyond the target pressure. We do however wholeheartedly agree with the authors on the importance of conducting a large-scale multinational randomised prospective trial as the only possible method to compare non-penetrating glaucoma surgery, or any other new surgical practice, to trabeculectomy.

Tarek Shaarawy¹, MD and André Mermoud², MD

1. Head Glaucoma unit, Memorial Research Institute of Ophthalmology, Giza, Egypt.
2. Head Glaucoma unit, University of Lausanne, Switzerland.

References

(1) Shaarawy T, Karlen M, Schnyder C, Achache F, Sanchez E, Mermoud A. Five-year results of deep sclerectomy with collagen implant. J Cataract Refract Surg 2001;27:1770-8.

(2) El Sayyad F, Helal M, El Kholify H, Khalil M, El Maghraby A. Nonpenetrating deep sclerectomy versus trabeculectomy in bilateral primary open-angle glaucoma. Ophthalmology 2000;107:1671-4.

(3) Sanchez E, Schnyder CC, Mermoud A. [Comparative results of deep sclerectomy transformed to trabeculectomy and classical trabeculectomy]. Klin Monatsbl Augenheilkd 1997;210:261-4.

(4) Jonescu-Cuypers C, Jacobi P, Konen W, Krieglstein G. Primary viscocanalostomy versus trabeculectomy in white patients with open-angle glaucoma: A randomized clinical trial. Ophthalmology 2001;108:254-8.

(5) Dietlein, T. S. and Krieglstein, G. K. Morphology and pressure- reducing efficacy after viscocanalostomy. 23. 2001. Paris, European Glaucoma Society. Closed Meeting of the European Glaucoma Society.

(6) Dietlein TS, Luke C, Jacobi PC, Konen W, Krieglstein GK. Variability of dissection depth in deep sclerectomy: morphological analysis of the deep scleral flap. Graefes Arch Clin Exp Ophthalmol 2000;238:405-9.

(7) Shaarawy, T., Nguyen Chr, Schnyder, C., Achache, F., and Mermoud, A. Comparative study between deep sclerectomy with and without collagen implant: Long term follow-up. Invest Ophthalmol42(4), S544. 2001.

Dear Editor

I read with great interest your case report on the leech bite to the eye sustained by a 4 year old girl in Germany - in particular that infestation of the human eye is very rare (“To our knowledge only one case is described in the literature”). While this may indeed be the case in Europe, here in Tasmania, the southernmost state of Australia, this event is evidently much more common and occasions a lot less excitement on the part of health professionals.

My experience of this occurred in January 2004 as I was bushwalking in the Cradle Mountain- Lake St Clair National Park. Leeches are quite common in the Tasmanian bush. They are land leeches and in some places in wet conditions can be in plague proportions. However in dry summer weather they are relatively uncommon. On the 5th day of our walk my daughter and I were climbing a pass at 1100 metres in a snowstorm when a flurry of snow blew into my right eye and with it something dark and rather large. When I couldn’t readily dislodge it, I called my daughter over and she identified it as a leech, very firmly attached and biting through the white of my eye.

The recommended ways of detaching leeches are to either apply salt or a flame, but we had no salt with us and had no intention of applying a flame near the eye. I toyed with the idea of using a solution of fruit saline to the eye, but wasn’t sure exactly what was in it and was loathe to risk harm to the eye with an unknown substance. The other way of getting rid of leeches is to irritate them with a gentle rubbing motion until they drop off - one is always counselled not to just pull them off.

None of these options seemed possible. In a matter of minutes the leech had inveigled itself so that only its head was visible at the inner corner of my eye, its tail just visible at the outer corner and its body totally inaccessible up under my upper eyelid. I briefly entertained the notion of letting it stay there until it had fed and dropped off, but its proximity to my tear duct began to worry me, given the speed with which it had already made itself at home. In the end I irritated it until it detached its back end and once I got a fair grip on it made one of those split second decisions - and yanked.

The eye bled profusely and I packed it with snow. However, as we dropped to lower altitudes, snow was no longer available and bleeding recommenced. By the time I reached a hut that afternoon the tissue around the eye was noticeably swollen and the eye itself was very bloodshot. The next morning (Monday) it looked worse rather than better so we set off to walk the 32 kilometres north to the nearest road, in order to get the eye seen to as soon as possible. We acquired salt from another walker and I bathed the eye with a saline solution several times during the day, in an effort to avoid infection. We got out of the bush by midday on Tuesday, but by the time we had driven the 400km to Hobart it was evening so doctors and ophthalmologists were largely unavailable and I ended up seeing a locum general practitioner at an After Hours clinic. He was new to Tasmania and hadn’t seen a similar case, so he conferred with the casualty section of the local hospital, but they really just confirmed his initial advice to me.

We all agreed there appeared to be no vision problems involved. If I had cared to queue up at the hospital for 3-4 hours I could have been checked out for corneal erosion, but I didn’t bother as the doctor and I were both pretty sure I didn’t have any. The doctor assured me that the subconjunctival bleeding (the white of my eye was entirely red) would disappear in 2 -3 weeks and in the event it took only 5 days for it to do so. As I was planning to return to the bush almost immediately I was prescribed Chloromycetin eye ointment to use in the event of the eye becoming infected, which didn’t occur. I was told that there was no need to see an eye specialist as there was nothing they could do.

Having been largely reassured by this visit, I thought I’d just check out the internet with leech/bite/eye where, amongst others, I found your journal reference and thought you might be interested in a related experience.