Suture supported P C IOL in a homocystinuric child.SS Bhatti, AP Agashe, RP Jehangir
Department of Ophthalmology, KEM Hospital, Parel, Mumbai 400012.
A homocystinuric child presented with a secondary pupillary block glaucoma due to anteriorly subluxated lens. After removal of the subluxated lens, a suture supported posterior chamber IOL was implanted. Postoperative complication of cerebral venous thrombosis following general anaesthesia was managed with high doses of pyridoxine special diet and drugs.
Keywords: Anesthesia, General, adverse effects,Case Report, Child, Glaucoma, complications,surgery,Homocystinuria, complications,Human, Intracranial Embolism and Thrombosis, etiology,therapy,Lens Implantation, Intraocular, methods,Lens Subluxation, complications,surgery,Suture Techniques,
Homocystinuria ranks high as a cause of dislocated lenses. Here we present our experience of suture supported posterior chamber IOL implantation in a patient with homocystinuria, a high risk condition for general anaesthesia.
A twelve-year-old fair haired, mentally retarded, quiet homocystinuria child presented with anteriorly subluxated (incarcerated in the pupil) clear lens with severe secondary glaucoma in the left eye [Figure - 1]. Despite maximum medical treatment (without pilocarpine) and cycloplegics for 24 hours, the intraocular pressure was 31.8 mm of Hg (Schiotz) so an emergency lens extraction surgery was performed.
The patient was operated under general anaesthesia. After lids and superior rectus stitches, fornix based conjunctival flaps were made at 3 o'clock and 9 o'clock meridians. Limbus based partial thickness scleral flaps were prepared under these conjunctival flaps. [Figure - 2].
1. Conjunctival flaps. Lamellar scleral flaps and superior limbal section.
2. Lens delivery with vectis and lens expressor.
3. Anterior vitrectomy.
4. lOL prepared for implantation with suture support.
5. Transscleral stitches under lamellar scleral flap.
6. IOL implantation in horizontal meridian.
7. IOL in situ.
8. Closure of limbal section, scleral flaps and conjunctival flaps.
9. Cross section of anterior segment showing position of the IOL
A routine limbal section was taken from 10 to 2 o'clock meridians superiorly. The lens was delivered intracapsular with vectis and spatula and a generous anterior vitrectomy was performed. 10 deg. angulated J loop posterior chamber intraocular lens was prepared for implantation with suture support. 10-0 mersilene (code NW 6557) sutures were tied to both the loops and the tips of the loops were made bulbous by holding them close to red hot ball point cautery. The stitches were passed under the iris to emerge on the sclera 1 mm behind the limbus (thus traversing iridociliary sulcus) at 3 and 9 o'clock meridians.
Intraocular haemorrhage occurred at this stage, which was washed out as much as possible. The intraocular tens was then inserted and positioned in horizontal meridian. Intracameral pilocarpine was used to constrict the pupil. The mersilene stitches were tied under the scleral flaps. The scleral flaps, conjunctival flaps and limbal section were sutured. The air bubble was aspirated and intraocular pressure was normalised with Ringer Lactate solution.
Unfortunately, the patient did develop the complication of cerebral venous thrombosis postoperatively. The condition was successfully managed with heparin, Lomodex, dipyridamole, high doses of pyridoxine (200 mg 4 hourly), folic acid and a special diet to restrict methionine intake.
Although vision could not be recorded due to mental retardation, the drowsy child passively cooperated for fundus and tension examination. At one month post op. the IOP was 17.3 mm of Hg and vitreous haemorrhage was partly absorbed but fundus details were not clear. The right eye of the patient also showed inferonasal subluxated lens and was referred for Laser iridotomy. After discharge, the child was lost to follow-up.
Homocystinuria, an inborn metabolic error, is due to deficiency of enzyme cystathione beta synthetase. It is important as a cause of subluxated lenses, as a differential diagnosis of Marfan's syndrome and as a high risk condition for general anaesthesia.
Roughly 90 percent of homocystinuric children develop inferonasal subluxation of lens by the age of 10 years. If incarcerated in the pupil, such a lens given rise to secondary angle closure glaucoma due to pupiflary block. Medical management of such a condition consists of cycloplegics to dilate the pupil and relieve the pupillary block. in addition to hyperosmotic agents and carbonic anhydrase inhibitors.
If medical management fails, lens extraction has to be done by limbal approach or preferably by pars plana approach. Because the lens is subluxated and zonules are deficient. a posterior chamber iniraocuiar lens cannot be implanted without certain modification such as scleral support with nonabsorbable sutures. Such implantation of PC IOL in absence of zonular and capsular support has been described,. In fact, one suture supported (in case of zonular dialysis/PC rent) or two sutures supported (in case of very large zonular dialysis/PC rent/unplanned intracapsular lens delivery/Secondary lens implant in intracapsular aphakia) PC Lens implantation are well established procedures in adults.
Considering short life expectancy and uniocular aphakia (uncorrectable by aphakic glasses, contact lens or epikeratophakia), this procedure was performed in our patient, although we did not have sufficient data on safety and complications of this
procedure in children.
Homocystinurics are very prone to thrombotic phenomenon especially during general anaesthesia probably because of high blood homocystine levels. A diet poor in methionine and rich in cystine along with pyridoxine, foiate and eystathione supplements may reduce the risk of such episodes. Preoperative prophylactic anticoagulation may reduce the risk of thromboembolic phenomenon but increases blood loss during the surgery and severe hyphaema can result after lens extraction surgery.
[Figure - 1], [Figure - 2]