Abstract
Corneal topography may be affected by surgery to structures other than the cornea, although techniques usually aim to minimise this. In these cases, assessment of corneal shape can be useful in the investigation of otherwise unexplained visual loss and in the development of new techniques.
In trabeculectomy, excessive scleral cautery causes collagen contraction with local flattening and associated steepening of the paracentral cornea. The partial-thickness scleral flap and full-thickness sclerostomy beneath it can cause similar changes to peripheral corneal incisions: flattening if the incision is long and the sutures are too loose, steepening if the sutures are too tight and a spiral or steep/flat pattern with irregular astigmatism if one side is sutured more tightly than the other or if there is horizontal misalignment. A large anteriorly situated drainage bleb can collect a tear meniscus at its junction with the cornea, causing apparent flattening, similar to a pterygium.
After vitreous or retinal surgery, altered topography should be considered as a cause of reduced visual acuity. Of local explants, radial plombs tend to induce greater corneal steepening than circumferential scleral buckles, but both can produce an asymmetric bow tie with high astigmatism. Encircling bands generate peripheral corneal flattening, with central steepening, which contributes to a myopic shift, as does elongation of the axial length. Both external and internal approaches can cause swelling of the conjunctiva, leading to peripheral corneal flattening due to dellen or meniscus formation, as adjacent to pterygia or blebs.
Strabismus surgery can generate variable effects on corneal astigmatism, which tend to be short-lived. Horizontal muscle surgery tends to produce vertical corneal steepening, and a tear meniscus adjacent to conjunctival swelling can be associated with the appearance of local flattening. Effects can be minimised by attention to good technique, including the length of the suture bites and tension in the sutures.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
*References Particularly Worth Reading
Hugkulstone CE. Changes in keratometry following trabeculectomy. Br J Ophthalmol. 1991;75:217–8.
Cunliffe IA, Dapling RB, West J, Longstaff S. A prospective study examining the changes in factors that affect visual acuity following trabeculectomy. Eye. 1992;6:618–22.
Rosen WJ, Mannis MJ, Brandt JD. The effect of trabeculectomy on corneal topography. Ophthalmic Surg. 1992;23:395–8.
Chan HHL, Kong YXG. Glaucoma surgery and induced astigmatism: a systematic review. Eye Vision. 2017;4:27. https://doi.org/10.1186/s40662-017-0090-x.
*Claridge KG, Galbraith JK, Karmel V, Bates AK. The effect of trabeculectomy on refraction, keratometry and corneal topography. Eye 1995; 9: 292–298.
Vernon SA, Spencer AF. Intraocular pressure control following microtrabeculectomy. Eye. 1995;9:299–303.
Givner I, Karlin D. Alterations in refraction and their clinical significance. Eye Ear Nose Throat Monthly. 1958;37:676–8.
Jacklin HN. Refraction changes after surgical treatment for retinal detachment. South Med J. 1971;64:148–50.
Foire JV Jr, Newton JC. Anterior segment changes following the scleral buckling procedure. Arch Ophthalmol. 1970;86:284–7.
Goel R, Crewdson J, Chignell AH. Astigmatism following retinal detachment surgery. Br J Ophthalmol. 1983;67:327–9.
Weinberger D, et al. Corneal topographic changes after retinal and vitreous surgery. Ophthalmology. 1999;106(8):1521–4.
Ornek K, Yalçindag FN, Kanpolat A, et al. Corneal topographic changes after retinal detachment surgery. Cornea. 2002;21(8):803–6.
*Hayashi H, Hayashi K, Nakao F, Hayashi F. Corneal shape changes after scleral buckling surgery. Ophthalmology 1997; 104: 831–837.
Sinha R, Sharma N, Verma L, et al. Corneal topographic changes following retinal surgery. BMC Ophthalmol. 2004;4:10. https://doi.org/10.1186/1471-2415-4-10.
Marshall D. Changes in refraction following operation for strabismus. Arch Ophthalmol. 1936;15:1020–31.
Thompson WE, Reinecke RD. The changes in refractive status following routine strabismus surgery. J Pediatr Ophthalmol Strabismus. 1980;17:372–4.
Fix A, Baker JD. Refractive changes following strabismus surgery. Am Orthoptic J. 1985;35:59–62.
*Kwitko S, Feldon S, McDonnell PJ. Corneal topographic changes following strabismus surgery. Cornea 1992; 11: 36–40.
*Kwitko S, Sawusch MR, McKonnell PJ, Gritz DC, Moreira H, Evensen D. Effect of extraocular muscle surgery on corneal topography. Arch Ophthalmol 1991; 109: 873–878.
Preslan MW, Cilffi G, Yuan-I M. Refractive error following strabismus surgery. J Pediatr Ophthalmol Strabismus. 1992;29:300–4.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2019 Springer Nature Switzerland AG
About this chapter
Cite this chapter
Corbett, M., Maycock, N., Rosen, E., O’Brart, D. (2019). Ocular Surgery. In: Corneal Topography. Springer, Cham. https://doi.org/10.1007/978-3-030-10696-6_15
Download citation
DOI: https://doi.org/10.1007/978-3-030-10696-6_15
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-10694-2
Online ISBN: 978-3-030-10696-6
eBook Packages: MedicineMedicine (R0)