To the Editors:
Scierai perforation during squint surgery is a rare event, occurring in 1% to 2% of all cases.1 The procedure should be completed and the ftmdus examined on the operating table. If the retina is perforated, vitreous may appear at the entry point and should be trimmed. The development of a retinal detachment is rare and should be addressed promptly. Usually, however, the retina remains flat and a small hemorrhage may be observed around the perforation site. There are varying opinions about the appropriate management of these cases. Some surgeons advocate immediate cryotherapy or Argon retinopexy,2 whereas others adopt a more conservative approach of observation. The latter approach is further supported by a recent study on the role of prophylactic cryotherapy versus monitoring that has not detected any benefit from cryotherapy, because both groups recovered without any visual loss.1
Recession of a rectus muscle with a loop (hangback suture) was first described by Gobin in 1968. 3 It was aimed to provide recession of more than 5 mm, while ensuring that the muscle would maintain tangential contact with the globe. The technique can be used for esotropia, exotropia,4 dissociated vertical deviation, and adjustable suture surgery. Because the sutures are inserted through the thicker sclera at the muscle insertion, there is a decreased risk of scierai perforation. Postoperative results are similar to those with conventional squint repairs.5
A 13-year-old girl underwent squint surgery in our department.
She first presented in 1992. She was born at 24 weeks' gestation, weighing 512 g, and progressed to have threshold stage 3 retinopathy of prematurity (posterior zone 2). Regression of retinopathy of prematurity was achieved with cryotherapy.
She developed normally, achieving visual acuity of 6/9 corrected with a myopic prescription (right, -4.25/+0.25 × 180; left, -7.50M.50 × 180), but had a variable convergent squint measuring 14 to 25 D base out.
Progressively, the esotropia deteriorated to 45 D, and a right medial rectus recession and lateral rectus resection was performed in April 1999. There were no complications, and the squint decreased to 25 D.
The squint became more noticeable once again, and by March 2004, it measured 35 D for near and 45 D for distance.
Left squint surgery was performed. The procedure proved challenging because of conjunctival scarring. The medial rectus was disinserted, and on passage of the needle through tissue-thin sclera at 5 mm from the insertion site, a double perforation of the globe occurred. Watery fluid egressed from both the entry and exit sites, causing the eye to collapse, like a squashed grape.
The operation was aborted after the medial rectus muscle was sutured back to its insertion on a 5-mm hang-back suture. The shape of the eye was reestablished through injection of approximately 2.5 mL of balanced salt solution into the anterior chamber, and the scierai perforation was left to "self-seal." The perforation was visible on funduscopy and was within the area of previously cryotreated retina. No further treatment was required.
The postoperative cosmetic result was surprisingly satisfactory, and the patient made a good recovery, with intraocular pressure returning to normal after 3 days. No further intervention was necessary.
Cryotherapy-treated threshold retinopathy may be associated with high myopia, which alone or in combination with the effects of cryotherapy on a premature eye, can lead to an extremely thin sclera. In our case, liquifaction of the vitreous, known to occur in cryotreated eyes,6 led to a continuous leak of intraocular fluid because of the absence of normal vitreous to "plug" the wound.
After a reevaluation of our approach, we recommend that hang-back sutures be considered as the main suture technique for squint correction in such high-risk eyes.
1. Taherian K, Sharma P, Prakash P, Azad R. Sclera! perforations in strabismus surgery: incidence and role of prophylactic cryotherapy: a clinical and experimental study. Strabismus 2004;12:17-25.
2. Puri P Verma D, McKibbin M. Management of ocular perforation resulting from peribulbar anaesthesia. Indian J Ophthalmol 1999;47:181-183.
3. Gobin M. Recession of the medial rectus muscle with a loop. Ophthahnologica 1968;156:25-27.
4. Capo H, Repka M, Guyton M. Hang-back lateral rectus recession for exotropia. J ' Pediatr Ophthalmol Strabismus 1989;26:31-34.
5. Rupka M, Guyton D. Comparison of hang-back medial rectus recession with conventional recession. Ophthalmology 1988;89:317-322.
6. Hikichi T, Nomiyama G, Ikeda H, Yoshida A. Vitreous changes after treatment of retinopathy of prematurity. Jpn J Ophthalmol 1999;43:543-545.