Limbal dermoids are benign tumors that can contain a variety of histological tissue types.1 Indications for surgical removal of a limbal dermoid include amblyopia and amblyogenic risk factors (including clinically significant anisometropia, obstruction of visual axis, or astigmatism),1,2 ocular exposure (due to incomplete eyelid closure during sleep or induction of a dellen),1,2 lack of compliance with follow-up or with spectacle correction,1,2 or aesthetic and psychosocial reasons.1
Our patient presented on day 27 of life with a limbal dermoid noticeable by his parents. At that time, the lesion was not obscuring the visual axis, the vision was equal, and there was no induced astigmatism. It was determined that the child should be observed closely. By age 6 months, the lesion had grown slightly and there was some induced astigmatism with mild anisometropia. By age 9 months, it was determined that the limbal dermoid was significant enough to remove and the child was taken to the operating room for surgical excision.
Selection of the technique for dermoid removal can be based on the grade or size of the limbal dermoid.1 When surgical treatment is chosen, frozen sections to confirm complete removal are not typically used because dermoids are considered benign tumors. We prefer to make a conjunctival peritomy first and then create a lamellar dissection from the central cornea outward, taking care not to enter the anterior chamber. When excision is performed, for simplicity and lack of a better modality, the clinical appearance of visible white tissue is used to determine the necessity of widening or deepening the excision. A tool for confirming the depth of the tumor and to ensure complete removal would be valuable.
We used an intraoperative hand-held optical coherence tomography (OCT) device mounted on a surgical microscope (Bioptogen; Leica Microsystems, Inc., Buffalo Grove, IL) for imaging the lesion in this case. OCT assessment of limbal dermoids has been previously described.3 OCT imaging of limbal dermoids reveals a highly reflective lesion and the shadowing effect prevents full-depth visualization. Because of the density and reflectivity of the tumor, we could not use OCT to accurately image the entire extent of the tumor. However, because of this high reflectivity, we discovered that OCT could be used to confirm a complete excision of a limbal dermoid.
In our case, when the initial dissection of the tumor was complete, OCT was repeated and the presence of highly reflective tissue that created shadowing confirmed that dermoid tissue remained (Video 1, available in the online version of this article). The dissection was then repeated at a slightly greater depth followed by additional OCT imaging. The third OCT image showed no shadowing and the entire remaining corneal thickness could be appreciated. The presence or absence of this OCT shadowing effect intraoperatively was useful for confirmation of complete dermoid removal. Figure 1 illustrates how the hyperreflective nature of the dermoid and resulting posterior shadow can be seen in contrast to the clear posterior border of the surrounding cornea and sclera to demonstrate the presence (left), incomplete removal (middle), and complete removal (right) of a limbal dermoid.
This montage shows the cornea through the microscope (top row) corresponding with optical coherence tomography (OCT) imaging (bottom row). In the OCT images, the top is anatomically anterior. The conjunctiva and sclera are located at the bottom left of the OCT images, whereas the cornea is in the top right, with the limbus in between. Left (top and bottom): preoperative appearance. Middle (top and bottom): after initial excision. Right (top and bottom): after final excision, note absence of OCT shadowing in the bottom image, indicating absence of residual dermoid tissue.
Using OCT imaging added time to the procedure; however, that drawback was partially outweighed by the ability of this modality to confirm complete excision.
OCT-enhanced surgical microscopes have been increasing in popularity and their use is slowly growing in other anterior segment ophthalmic techniques, such as corneal suture and repair.4 OCT integration into surgical microscopes will facilitate and speed the use of OCT for limbal dermoid excision. A clinical trial of OCT as an intraoperative tool for assessment of complete dermoid removal has yet to be performed, but this case suggests that it may be a helpful adjunct for the ophthalmic surgeon.
- Pirouzian A. Management of pediatric corneal limbal dermoids. Clin Ophthalmol. 2013;7:607–614. doi:10.2147/OPTH.S38663 [CrossRef]
- Graff JM, Bhola R, Olson RJ. Goldenhar syndrome (oculo-auriculovertebral spectrum): 6 day-old male with limbal dermoids. Eyerounds.org. March31, 2006. Available from: http://www.EyeRounds.org/cases/55-GoldenharSyndromeLimbalDermoidColoboma.htm.
- Cauduro RS, Ferraz Cdo A, Morales MSÁ, et al. Application of anterior segment optical coherence tomography in pediatric ophthalmology. J Ophthalmol. 2012;2012:313120. doi:10.1155/2012/313120 [CrossRef]
- Todorich B, Shieh C, DeSouza PJ, et al. Impact of microscope-integrated OCT on ophthalmology resident performance of anterior segment surgical maneuvers in model eyes. Invest Ophthalmol Vis Sci. 2016;57:146–153. doi:10.1167/iovs.15-18818 [CrossRef]