Simple limbal epithelial transplantation (SLET) has been widely used for surgical management of unilateral and bilateral limbal stem cell deficiency.[1,2] In autologous SLET or allogeneic SLET (live-donor), one clock hour or 3.5–4 mm limbal biopsy is procured using the standard surgical technique.[1] The limbal biopsy is harvested from the superior limbus by dissection of a limbus-based conjunctival flap. For pterygium surgery, pterygium excision with conjunctival autograft (CAG) is the gold standard surgery due to the least risk of recurrence.[3] In both surgeries SLET and pterygium, mostly a superior bulbar area is used to harvest limbal or conjunctival tissue, respectively, and hence an adequate exposure of this area is necessary. This can be challenging, especially in patients with small palpebral fissure. Currently, superior rectus bridle suture, manually rotating the eye downwards using a sterile cotton bud, or corneal traction suture through the superior peripheral cornea is used to aid in the visualization of the superior conjunctiva. We describe the use of Ong speculum, which is commonly used in glaucoma surgeries, to increase the exposure of the superior conjunctiva without the use of any additional above-mentioned maneuvers.
Surgical Technique
The anterior and posterior blade of the superior arm of the Ong speculum is 5 mm in size, which is similar to a standard speculum. On the other hand, the inferior arm is larger. The anterior blade of the inferior arm is 5 mm, whereas the posterior blade has a 5-mm section to cradle the margin and an additional 7–10-mm section, which is angled and curved posteriorly to push on the inferior conjunctival fornix. Hence, the posterior blade is 12–15mm in length [Fig. 1a, 1e].[4] The inferior fornix is 8–10 mm from the limbus.[5] Thus, the large inferior blade of the Ong speculum pushes the inferior conjunctival fornix down by 5–7 mm, thereby rotating the eyeball downwards.[4] It can be an open-wire speculum or an adjustable speculum. With the adjustable mechanism, the amount of infraduction can be varied depending on the requirement.
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Figure 1: Photograph of Ong speculum and collage depicting its use in SLET and pterygium surgery (a–e) Larger inferior blade of the Ong speculum can be appreciated for the right and left eye. (b–d) Ong speculum while harvesting limbal biopsy from the donor eye. The superior conjunctiva is exposed without the need for any manual manipulation, superior bridle suture, or corneal traction suture. (f) Eye in primary gaze when the speculum is minimally opened. The steps of pterygium excision can be performed in this orientation. (g) The speculum is opened to increase the infraduction, making the superior conjunctiva more accessible to harvest the CAG. (h) The speculum can be closed again to bring back the eye in the primary position, so that the autograft can be secured on the bare sclera
An Ong speculum is used for a variety of glaucoma surgeries like trabeculectomy, needling of a filtration bleb, or sub-conjunctival 5-fluorouracil injections where exposure of the superior conjunctival is required.[4,6] However, its use in other ocular surgeries has not been described before.
Results
Due to the design of the Ong speculum, it was used successfully in five patients undergoing autologous SLET. The posterior blade pushed the inferior conjunctiva downwards. This increased the exposure of the superior conjunctiva and limbus. Due to this, the limbal biopsy could be harvested easily without the need for any manipulation [Fig. 1b–d]. Also, the adjustable Ong speculum was used in the recipient’s eye while pannus dissection. Its position and amount of opening were adjusted to expose the area of the desired dissection. The Ong speculum was flipped for use in the eye with limbal stem cell deficiency (LSCD) because we wanted supraduction of the eyeball as we wanted to work on the inferior region for symblepharon release [Video Clip].
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The Ong speculum was also used in pterygium surgery. When the speculum was minimally opened, the eye was in primary gaze. The pterygium excision could be done while maintaining the speculum in this orientation [Fig. 1f]. When the superior CAG had to be harvested, the speculum was opened to increase the amount of infraduction such that the superior sclera and conjunctiva could be exposed. The CAG could be measured and harvested easily without the need of any manual manipulation [Fig. 1g, 1h].
Discussion
Adequate exposure of the superior conjunctiva and limbus can be obtained during SLET or pterygium excision surgery with superior rectus bridle suture, or by manually rotating the eye downwards using a Merocel sponge. Additionally, corneal traction suture may be taken in SLET through the superior peripheral cornea to aid in the visualization of the superior conjunctiva.
The superior rectus bridle suture is used to increase exposure to the superior part of the globe, especially during cataract surgery. It is also used in SLET for a similar reason. However, it can lead to levator aponeurosis dehiscence, which can increase the risk of postoperative ptosis.[7,8] Rarely, retinal injury has also been reported due to a bridle suture.[9]
A corneal traction suture through superior peripheral cornea can cause minimal trauma, leading to scar formation due to inflammation.[4] Though rarely, it can also become a site of epithelial ingrowth or microbial keratitis.[10]
While a manual rotation of the globe with a sponge does not cause any trauma, it increases the dependency on an assistant.
Ong speculum overcomes the disadvantages as described above. Ong speculum can help in superior pannus dissection by increasing the exposure of the superior globe. Its availability as small and large, as well as the adjustable mechanism, increases its utility depending upon the size of the patient’s palpebral aperture and the amount of infraduction required. Thus, when the speculum is opened incompletely, the maneuvers required in the primary gaze can be performed. On the other hand, the amount of opening can be adjusted to increase the superior exposure when maneuvers are to be performed in the superior globe.
Conclusion
Ong speculum increases the exposure of the superior conjunctiva, thereby making the less accessible area approachable. It can be used in SLET and pterygium surgery to harvest limbal biopsy and conjunctival autograft, respectively.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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