A 35-year-old man (K.E) was first seen in our clinic as an outpatient due to a rapid deterioration of vision in his right eye associated with pain and tearing, over a period of one month. He also noted a gradual decline of vision in his right eye over the previous year. His medical history included TS diagnosis since childhood, asthma, mild depression and low grade myopia in both eyes from the age of 7. He was on aripiprazol, clonazepam and sertraline. During the examination the patient did not have extensive vocal tics but he manifested several motor tics including frequent bilateral eye rubbing. The patient did not have any symptoms of ocular itching or irritation and on questioning he reported vigorous rubbing in both eyes.
At baseline examination, best corrected visual acuity (BCVA) was counting fingers at 0,5 m in the right eye and 9/10 in the left eye (with -2,50 sph, -1,50 cyl × 90 correction). Slit lamp biomicroscopy of the right eye showed a central stromal scar secondary to corneal hydrops (Figure ), while his left eye was normal. There was no evidence of papillary or follicular lesions on both tarsal conjunctivae. His intraocular pressures were normal. Corneal topography of his left eye was normal (Figure ).
Biomicroscopic appearance of the right eye at presentation showing central stromal scar (a) and 4 years after presentation showing phthisis (b). Short title: Biomicroscopic appearance of the right eye at presentation and 4 years later.
Corneal topography of the left eye at presentation with normal findings (a) and 4 years after presentation showing keratoconus (b). Short title: Corneal topography of the left eye at presentation and 4 years later.
Axial lengths as measured by immersion A-scan ultrasonography were 25,14 mm in the right eye and 24,71 mm in the left eye, while B-scan ultrasonography did not show any pathologic findings.
We treated the right eye with hypertonic saline drops, cycloplegic drops and advised the patient to avoid eye rubbing.
Six months later, the patient presented complaining of sudden drop in vision in his left eye. BCVA was counting fingers at 33 cm in his right eye and had declined to 1/10 in the left eye. Slit lamp biomicroscopy showed corneal hydrops of the left eye with accompanying epithelial loss. We treated the left eye with topical hypertonic saline drops, cycloplegic drops, oral acetazolamide, an eye shield at night and strongly advised him to avoid eye rubbing. We also contacted the patient's general practitioner which informed us that the patient did not had a close psychiatric surveillance, while he failed to appear in many of his routine appointments over the last years.
One year later BCVA was hand motion in his right eye and counting fingers at 2 m in his left eye with normal light projections while during the following months his vision continued to deteriorate in both eyes with central stromal scar formation in the left cornea (Figure ). Corneal topographies of his left eye showed a corresponding progression (Figure ). Four years after presentation BCVA was no light perception in the right eye and counting fingers at 33 cm in the left eye. His right eye was phthisic (Figure ).
Biomicroscopic appearance of the left eye showing central stromal scar.
Keratoconus is a bilateral non-inflammatory corneal ectasia with an incidence of approximately 1 per 2000 in the general population [6
]. Although its most common presentation is as an isolated sporadic disorder, it has also been associated with various diseases. An indication of a connection between keratoconus and TS is implied in a preliminary report by Enoch et al [5
]. In this report which primarily investigates visual field defects in a group of 12 patients with TS, it is noted that two patients exhibited keratoconus, with no further analysis concerning the aetiologic relationship between the two conditions. Furthermore, Mashor et al recently described three cases of patients with TS-provoked eye rubbing that exhibited keratoconus [7
There are multiple studies that report a high association of eye rubbing with keratoconus, but a cause-and-effect relationship is difficult to be established [8
]. The association is implied by the high percentage of keratoconus patients with a positive history of eye rubbing. The reported prevalence ranges from 66% to 73% [9
]. Rabinowitz performed a case-control study which showed that keratoconus patients do rub their eyes more often than normal controls (80% versus 58%, p < 0.001) [6
]. Furthermore, keratoconus relates to a variety of conditions in which eye rubbing is a common feature like vernal atopic disease [10
], Trisomy 21 [11
] and Leber's tapeto-retinal degeneration [12
]. Mechanical trauma has been implicated in the pathogenesis of keratoconus and the proposed mechanisms include increased apoptosis and increased oxidative damage [13