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Editor,—A well formed inferior fornix in the anophthalmic socket requires an adequate amount of conjunctival tissue and a deep recess. Obliteration of the fornix might occur either secondary to conjunctival shrinkage or as a result of obliteration of the inferior recess and inadequate fixation of the abundant conjunctiva.1 In the latter condition, the subject of this report, prolapse of the forniceal conjunctiva will result in anterior rotation of the inferior edge of the prosthesis and secondary laxity of the lower lid.
This report presents a modification of the technique described previously by Neuhaus and Hawes for the correction of the above condition.1
Twenty patients with an inadequate inferior fornix and sufficient amount of conjunctival tissue who presented over a period of 5 years were managed. They all complained of easy prolapse of the lower edge of the prosthesis and sagging of the lower lid.
The procedure was done under local anaesthesia except in the two patients who, in addition, underwent secondary insertion of an orbital implant. A canthotomy and cantholysis were performed. An infratarsal conjunctival incision was carried out along the length of the lower lid. Dissection was then performed in the retro-orbicular plane till the orbital rim was reached (Fig1A). The posterior edge of the conjunctival incision was fixed to the periosteum about 5 mm posterior to the inferior orbital rim with interrupted 5-0 Vicryl sutures. The posterior surface of the lower lid was left to heal by secondary intention (Fig 1B). An adequately sized conformer was inserted. A tarsal strip procedure was performed to tighten the lower lid horizontally.2 A prosthesis was fitted at about the second postoperative month. The follow up period ranged from 5 months to 3 years. Nineteen patients had a satisfactory result with adequate retention of the prosthesis, and good lower lid level. Inspection of the lower fornix revealed a deep recess with a well epithelialised inner lower lid surface, and no evidence of symblepharon (Fig 2). One patient had loosening of the tarsal strip suture noted at the 1 week postoperative follow up and was later corrected. However, the final lid level remained unsatisfactory.
Adequate retention of the prosthesis in the anophthalmic socket requires a well formed inferior fornix, which in turn requires sufficient conjunctival length and a deep recess.
Obliteration of the inferior fornix might occur despite having a good amount of conjunctival tissue.1 This occurs possibly because of dehiscence of lower lid retractors, or development of scar tissue in the inferior recess that ultimately results in prolapse of the forniceal conjunctiva and anterior rotation of the lower edge of the prosthesis. The long term effect exerted by the weight and pressure of an improperly accommodated prosthesis will result in secondary laxity of the lower lid.
The traditional solution to the above condition consisted of a lateral canthal tendon tightening and a fornix reformation using an externalised suturing technique in addition to alloplastic stenting material.3 Skin erosion and infection necessitated early removal of the externalised sutures and increased the risk of recurrence.
Another method of repair was described by Neuhaus and Hawes1 for the correction of the inadequate inferior cul de sac. It consisted of a transconjunctival inferior fornix incision used to gain direct exposure of the periosteum of the inferior orbital rim. Direct suture fixation of the edges of the conjunctival incision to the periosteum is then achieved. Externalised sutures and stents were not required. Out of 12 patients reported in the above paper, two developed mild lower lid retraction and two developed mild lower lid entropion. This is because the vertical length of the conjunctival tissue is not always sufficient to allow for fixation of both edges of the incision down to the periosteum. Lower lid retraction or entropion occurs whenever the anterior edge of the incision is forced down and sutured under tension.
The technique described in this report makes the conjunctival incision just at the infratarsal border so as to save the maximum length of conjunctiva for the posterior flap. By this, the inner lid surface is left to heal by secondary intention. The tarsal strip procedure performed during the surgery aims to eradicate the lower lid laxity and sag.2
In conclusion, this modified technique allows the use of internal fixation to correct the lower fornix while minimising the risk of lower lid retraction or entropion.