Astigmatism after corneal thermal injury

Dr. Priya Srinivas FRCS, Cornea Fellow, Sankara Nethralaya

Shree Eye care, Mumbai

Case Report

Purpose

To report a case of high astigmatism induced by a thermal burn to the cornea

and its regression over a period of 19 months

Methods

A 43 year gentleman presented with accidental thermal injury to the left eye with a burning agarbatti(incense stick) 15 days before presentation

He complained of blurred vision in the left eye He was prescribed topical steroids, antibiotics and lubricants

by the referring clinician for 2 weeks

Clinical PresentationEye UCVA BCVA

(pinhole)Near

visionRight eye (OD) 6/6 6/6 N6Left eye (OS) Finger

counting at 3m6/36 N36

Eye OD OSLids Normal Normal

Conjunctiva/fornices Normal NormalLimbus Normal Normal

Cornea Normal Abnormal distortion of temporal cornea, DM folds, scarring

AC Normal Normal

Iris / Pupil Normal NormalLens Normal Normal

Fundus Normal Normal

IOP ( GAT) 18mm Hg 30 mm Hg

Topography

K1- 53.48 D @160 K2 - 43.41 D @70 Diff =10.07 D

Cyl 10.07 D

Methods

No improvement with spectacle correction Anti-Glaucoma medication - Brimonidine plus timolol eyedrops

twice daily was prescribed Steroids eyedrops were tapered and stopped Option of Contact lenses(RGP) trial after stabilization of

topography was discussed

Results - 4 months follow up

Eye OD OSLids Normal NormalConjunctiva/fornices Normal Normal

Limbus Normal NormalCornea Normal DM folds, scarring,

distortion less obviousAC Normal NormalIris / Pupil Normal NormalLens Normal NormalFundus Normal NormalIOP ( GAT) 18mm Hg 08 mm Hg

Eye UCVA BCVA(pinhole)

Near vision

Right eye (OD) 6/6 6/6 N6

Left eye (OS) 6/18 6/9 N10

Cyl 7.22D

Results - 19 months follow upEye UCVA BCVA (pinhole) Near visionRight eye (OD) 6/6 6/6 N6

Left eye (OS) 6/6 6/6 N6

Eye OD OSLids Normal NormalConjunctiva/fornices

Normal Normal

Limbus Normal NormalCornea Normal CLEAR

AC Normal NormalIris / Pupil Normal NormalLens Normal NormalFundus Normal NormalIOP ( GAT) 18mm Hg 18 mm Hg

Cyl 0.81 D

Results (Follow up topography)Time K1 K2 Cylinder0 month 53.48 @160 43.41@70 10.07 D

4 months 49.53@156 42.31@66 7.22D

19 months 43.83@135 43.02@45 0.81D

Discussion -Literature search

Corneal thermal burns by boiling fluids1, firecrackers1 and electric curling irons3can affect the corneal epithelium (89%) , Superficial stroma (8%) and even cause perforation1 (3%)

A very high corneal astigmatism (6.86 D) was induced by a thermal burn during a cosmetic eyelid procedure which resolved partially and the residual astigmatism required an astigmatic keratotomy2

11 Vajpayee R B, Gupta NK, Angra SK, Chhabra VK, Sandramouli S, Kishore K. Contact thermal burns of the cornea. Can J Ophthalmol. 1991 Jun;26(4):215-8. Vajpayee R B, Gupta NK, Angra SK, Chhabra VK, Sandramouli S, Kishore K. Contact thermal burns of the cornea. Can J Ophthalmol. 1991 Jun;26(4):215-8.

22 Brian Chou, OD, Brian S. Boxer Wachler, MD .Astigmatism after corneal thermal injury. J Cataract Refract Surg 2001; 27:784–786 Brian Chou, OD, Brian S. Boxer Wachler, MD .Astigmatism after corneal thermal injury. J Cataract Refract Surg 2001; 27:784–786

3 3 Mannis MJ, Miller RB, Krachmer JH. Contact thermal burns of the cornea from electric curling irons. Am J Ophthalmol. 1984 Sep 15;98(3):336-9.Mannis MJ, Miller RB, Krachmer JH. Contact thermal burns of the cornea from electric curling irons. Am J Ophthalmol. 1984 Sep 15;98(3):336-9.

Discussion In our case, the blink reflex didn't help in avoiding / minimizing

the damage Localized thermal damage caused shrinkage of collagen fibres

(same principle as thermal keratoplasty) An irregular astigmatism (10D cylinder) was induced by the

thermal burn The astigmatism resolved with no refractive correction and so

did the visual acuity. We do not know the exact time required for regression of the astigmatism because there was a gap of 15 months after the 4 month follow up

Corneal thermal injury can induce a very high irregular astigmatism because of localized shrinkage of stromal collagen

While RGP CLs form the mainstay of visual rehabilitation, spontaneous regression of astigmatism over time is likely to occur

An adequate waiting period of at least one year is recommended before embarking on any refractive procedure.

Conclusion