Cornea 19(4): 567–569, 2000. © 2000 Lippincott Williams & Wilkins, Inc., Philadelphia

Keratoconus Associated with Continual Eye Rubbing due to Punctal Agenesis

Richard G. Lindsay, B.Sc.Optom., M.B.A., F.A.A.O., Dip.C.L., Adrian S. Bruce, B.Sc.Optom., Ph.D., F.A.A.O., and Ian F. Gutteridge, M.Sc.Optom., F.A.A.O.

Purpose. To highlight a possible causal effect of eye rubbing in in this condition associated with .1 However, a causal the etiology of . Methods. A 43-year-old man pre- relationship between eye rubbing and keratoconus has been diffi- sented to the practice of one of the authors (I.F.G.) with the com- cult to prove.5 If a case of unilateral keratoconus was shown to plaint of gradual onset reading difficulty. History revealed the have developed where there had been a history of digital rubbing patient to have experienced constant epiphora in the right eye solely confined to the affected eye, it would lend support to the throughout his life as a result of punctal agenesis, which necessi- theory that mechanical trauma is a major etiologic factor in the tated frequent wiping of this eye. Vision in the patient’s right eye had been reduced for approximately 20 years. Results. Based on development of keratoconus. ocular examination, the patient was diagnosed as having unilateral A case of unilateral keratoconus is presented where there is a keratoconus in the right eye. Conclusion. It is thought by some confirmed history of eye rubbing and wiping as a result of punctal that keratoconus is associated with, or indeed caused by, persistent agenesis in the ipsilateral eye. The contralateral eye, without rubbing of the anterior eye. While a number of studies support a symptoms of epiphora or a history of eye rubbing, was devoid of genetic basis for keratoconus in some patients, it is possible that any evidence of keratoconus. mechanical factors play a role in the development of this condition in other patients. This paper presents a case of unilateral kerato- conus, where there is a confirmed history of habitual eye rubbing CASE REPORT and wiping of excess as a result of punctal agenesis in the ipsilateral eye, thereby suggesting a possible causal relationship of A 43-year-old man presented to the practice of one of the au- eye rubbing in the etiology of keratoconus. thors (I.F.G.) with the complaint of gradual onset reading diffi- Key Words: Keratoconus—Eye rubbing—Mechanical trauma— culty. He had been told that he had been born without lacrimal Punctal agenesis. puncta in the right eye. Surgery was recommended at age 18 months; however, the patient’s parents decided not to proceed at this time as they had been advised that “there was a significant risk of permanent scarring” with this option. Consequently, the patient Keratoconus is a progressive disorder, with an onset anywhere had experienced constant epiphora in the right eye throughout his between 8 and 40 years of age, in which the assumes a life that necessitated frequent wiping of this eye. The patient es- conical shape as a result of noninflammatory thinning of the cor- timated that his right eye was wiped with a handkerchief about 50 neal stroma. It is usually a bilateral disease but is often asymmet- times a day due to this congenital absence of the puncta. He ric. True unilateral keratoconus is rare; although, only one eye may described that, in addition to wiping the eye, he used a rubbing be affected initially.1,2 The real incidence of unilateral keratoco- action involving a pushing into the prior to wiping from the nus has certainly undergone a significant downward revision over inner canthus in a temporal direction. The left eye was normal, as the last few years3,4 with the introduction of computer-assisted far as the patient was concerned, with no epiphora and with no videokeratoscopy enabling the detection of keratoconus in fellow history of excessive or unusual eye rubbing. eyes that otherwise appear relatively normal on ocular examination. The patient believed that the vision in his right eye had been It is thought by some that keratoconus is associated with, or below normal for approximately the last 20 years. He recalled that indeed caused by, persistent rubbing of the anterior eye.1 For ex- all visual examinations during childhood (up to age 17) had ap- ample, the frequent occurrence of keratoconus in Down’s syn- parently revealed normal visual acuities in both eyes. Decreased drome is sometimes attributed to the high incidence of eye rubbing visual acuity in the right eye was then first noticed at a vision screening performed when the patient was 23 years old. Submitted August 2, 1999. Revision received November 11, 1999. Ac- Thorough questioning revealed no other ocular problems, pres- cepted November 23, 1999. ent or past. There was no significant familial ocular history. The From the Department of Optometry and Vision Sciences (R.G.L., patient’s general health was excellent, with no current allergy or A.S.B., I.F.G.), University of Melbourne, and the Victorian College of atopy, although he did advise that he had suffered from asthma Optometry (A.S.B.), Australia. Address correspondence and reprint requests to Dr. Richard G. between the ages of 6 and 15. He was not using any medication on Lindsay, 376 Albert Street, 6th Floor, East Melbourne VIC 3002, a regular basis. Australia. Unaided vision of 6/30 OD, 6/6++ OS was improved to 6/7.5

567 568 R.G. LINDSAY ET AL.

OD, 6/4.8 OS with a manifest refraction of +1.50/−3.75 × 85 OD, −0.25 diopter sphere (DS) OS. Pinhole in the right eye further improved acuity to 6/6 OD. A scissors reflex was obtained with retinoscopy in the right eye while the left retinoscopic reflex was normal. A +1.00 D addition gave N4 near acuity. The explanation for the patient’s presenting complaint was early for which reading spectacles were prescribed. Slit-lamp examination showed an absence of the superior and inferior punctum lacrimale in the right eye. In the left eye, only the superior punctum lacrimale was present. This is illustrated dia- grammatically in Figure 1. It was not possible to determine wheth- er the patient lacked canaliculi as well as lacrimal puncta in the right eye. Very slight corneal thinning was noted in the right eye, about 1 mm inferior to the visual axis, while the left cornea was normal. There were no signs of any corneal opacification or striae FIG. 2. Topographic map of the patient’s right cornea. Note the in- in either eye. ferior steepening typical of keratoconus. Videokeratoscopy with the TMS-2 (Computed Anatomy Inc., New York, NY, U.S.A.) gave a topographic map indicative of Eye rubbing has been implicated in the pathogenesis of kerato- early keratoconus in the right eye (Fig. 2) with distinctive asym- conus. Indeed, it has been postulated that the usual inferior loca- metric pattern and localized inferior steepening. The topographic tion of the cone in keratoconus is due to the presence of the most map of the left cornea revealed a small degree of with-the-rule senile epithelial cells in this location, with these cells possibly without suggestion of keratoconus (Fig. 3). more vulnerable than the younger epithelial cells to the subtle All other aspects of the ocular examination were unremarkable. trauma of eye rubbing and, therefore, possibly more prone to re- Based on these findings, a diagnosis of unilateral keratoconus in leasing enzymes that thin the cornea.9 A high association of eye the right eye was made. The patient was well adapted to the poor rubbing with keratoconus has been reported in the literature, al- vision in the right eye, so spectacle or contact correction of though, as was stated earlier, a cause-and-effect relationship is this eye was not considered necessary. difficult to prove.5 Coyle10 reported the case of a boy who was born with an atrial DISCUSSION ventricular septal defect and who underwent open heart surgery at the age of two years. The operation was successful; however, he The case presented in this paper is interesting in that it involves subsequently developed paroxysmal atrial tachycardia. At the age a relatively rare clinical entity—unilateral keratoconus—where the of five years, the boy discovered that the tachycardia could be unilateral nature of the condition could be explained by a history stopped by vigorously massaging his left eye (presumably due to of unilateral mechanical trauma (eye rubbing) due to punctal agen- stimulation of the oculocardiac reflex). Ocular examination at age esis in the same eye. seven years revealed no abnormalities and visual acuities of 6/6 in Tears are lost from the eye by lacrimal drainage and evapora- both eyes. When he was 11 years old, the boy was found to have tion. Epiphora may result from lacrimal drainage obstruction, ne- keratoconus in his left eye with best corrected acuity of only 6/18. cessitating wiping or rubbing of the eye. Evaporation of the tears There was no sign of keratoconus in the right eye, with visual is a continual feature of the open eye, and is controlled by both the acuity in this eye still 6/6. superficial lipid layer of the precorneal tear film and the mecha- Gritz and McDonnell11 reported the case of a man who devel- nism and rate of blinking.6 The lipid layer inhibits evaporation, oped keratoconus in his right eye over a period of less than a year, especially in conditions of low humidity and turbulent tear flow.7 apparently as a result of pressing vigorously with his fist against Interestingly, this patient experienced no symptoms of epiphora in the left eye, which lacked the inferior punctum. With respect to lacrimal drainage, about 70% of the tears drain through the lower canaliculus and the remainder through the upper canaliculus.8 Pre- sumably there was sufficient loss of tears by evaporation and via the upper punctum to prevent epiphora in this eye.

FIG. 1. Diagram summarizing configuration of present punctum lac- FIG. 3. Topographic map of the patient’s left cornea. No sign of rimale and agenesis of other puncta. keratoconus is noted.

Cornea, Vol. 19, No. 4, 2000 UNILATERAL KERATOCONUS AND EYE RUBBING 569 this eye to aid in daily ritual meditation. On initial examination, Acknowledgment: The authors would like to thank Dr. Suit May Ho for this eye had appeared normal; even photokeratoscopy was not able the line drawing of Figure 1. to detect any sign of keratoconus. Eleven months later, the patient had reduced vision in this eye as a result of significant keratoconus. REFERENCES Keratoconus is seen in a number of clinical syndromes, many of 12 which are strongly associated with eye rubbing. A wide variety 1. Rabinowitz YS. Keratoconus. Surv Ophthalmol 1998;42:297–319. of atopic conditions are associated with keratoconus and studies 2. Lawless M, Coster DJ, Phillips AJ, Loane M. Keratoconus: diagnosis have shown that the incidence of atopy in patients with keratoco- and management. Aust J Ophthalmol 1989;17:33–60. nus is significantly higher than in the general population.12,13 3. Wilson SE, Lin DTC, Klyce SD. Corneal topography of keratoconus. Cornea 1991;10:2–8. Atopic patients with ocular involvement are especially prone to 4. Rabinowitz YS, Nesburn AB, McDonnell PJ. Videokeratography of eye rubbing to relieve the annoying and persistent symptom of the fellow eye in unilateral keratoconus. 1993;100: itchiness. Patients with Down’s syndrome have a higher frequency 181–6. of keratoconus compared to the general population. This is often 5. Krachmer J, Feder S, Belin M. Keratoconus and related noninflam- matory corneal thinning disorders. Surv Ophthalmol 1984;28:293– thought to be due to the high incidence of eye rubbing associated 322. 1 with increased blepharitis. Patients with Leber’s congenital am- 6. Iwata S, Lemp MA, Holly FJ, Dohlman CH. Evaporation rate of water aurosis rub their eyes to stimulate the and this condition is from the precorneal tear film and cornea in the rabbit. Invest Ophthal- also often associated with keratoconus.14 mol Vis Sci 1969;8:613–9. Studies have shown that the number of keratoconic patients 7. Holly FJ. Formation and stability of the tear film. Int Ophthalmol Clin 13,15,16 1973;13:73–9. reported to rub their eyes varies from 12–80%. More im- 8. Kanski J. Clinical ophthalmology, 3rd ed. London: Butterworths, portantly, it has not yet been proven conclusively that keratoconic 1994:60–1. patients rub their eyes more often than nonkeratoconic patients. 9. Baum J. On the location of the cone and the etiology of keratoconus. While one recent study showed that keratoconus patients do rub Cornea 1995;14:142–3. their eyes more often than normal controls (80% vs. 58%),15 an- 10. Coyle JT. Keratoconus and eye rubbing. Am J Ophthalmol 1984;97: 527–8. other recent prospective study of patients attending a large opto- 11. Gritz DC, McDonnell PJ. Keratoconus and ocular massage. Am J metric practice indicated that keratoconus patients do not rub their Ophthalmol 1988;106:757–8. eyes more often than normal controls (12% vs. 8%).13 Interest- 12. Karseras AG, Ruben M. Aetiology of keratoconus. Br J Ophthalmol ingly, the Collaborative Longitudinal Evaluation of Keratoconus 1976;60:522–5. study reported that 48.2% of keratoconic patients rubbed both eyes 13. Bruce AS, Armitage JA, Phillips AJ, Lindsay RG. Systemic associa- 16 tions, familial histories and the aetiology of keratoconus [abstract]. vigorously, whereas 2.2% rubbed only one eye. Optom Vis Sci 1997;74(suppl):147. There is the possibility that the patient described in this paper 14. Krachmer JH. The case for eye rubbing as the major cause of kerato- may have had some genetic predisposition to develop keratoconus. conus. In: Lass, ed. Advances in corneal research. New York: Plenum It is interesting to note that mechanical effects, such as Press, 1997:499–501. pressure, can lead to corneal distortion, albeit temporary in nature, 15. Tretter T, Rabinowitz YS, Yang H, Rotter JI. Etiological factors in 17 keratoconus. Ophthalmology 1995;102(suppl):156. even in patients who do not have keratoconus. While a number 16. Zadnik K, Barr JT, Edrington TB, et al. Baseline findings in the of studies support a genetic basis for keratoconus in some pa- Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. tients,13,18 it is possible that mechanical factors play a role in the Invest Ophthalmol Vis Sci 1998;39:2537–46. development of this condition in other patients. 17. Bowman KJ, Smith G, Carney LG. Corneal topography and monocular following near work. Am J Optom Physiol Opt 1978;55:818– This case report cannot be said to prove that eye rubbing can 23. cause keratoconus. It does, however, highlight a possible causal 18. Bechara SJ, Waring GO, Insler MS. Keratoconus in two pairs of iden- effect of eye rubbing in the etiology of keratoconus in some patients. tical twins. Cornea 1996;15:90–3.

Cornea, Vol. 19, No. 4, 2000