Fibrinous anterior uveitis following laser in situ keratomileusis

A 29-year-old woman who underwent laser in situ keratomileusis (LASIK) for myopic astigmatism in both eyes presented with severe pain, photophobia and decreased visual acuity in the le ft eye eight days a ft er surgery. Examination revealed severe anterior uveitis with (cid:222) brinous exudates in the anterior chamber, (cid:223) ap edema and epithelial bullae. Laboratory investigations for uveitis were negative and the patient required systemic and intensive topical steroids with cycloplegics to control the in (cid:223) ammation. This case demonstrates that severe anterior uveitis may develop a ft er LASIK and needs prompt and vigorous management for resolution. (cid:223)

A 29-year-old woman who underwent laser in situ keratomileusis (LASIK) for myopic astigmatism in both eyes presented with severe pain, photophobia and decreased visual acuity in the left eye eight days aft er surgery. Examination revealed severe anterior uveitis with Þ brinous exudates in the anterior chamber, ß ap edema and epithelial bullae. Laboratory investigations for uveitis were negative and the patient required systemic and intensive topical steroids with cycloplegics to control the inß ammation. This case demonstrates that severe anterior uveitis may develop aft er LASIK and needs prompt and vigorous management for resolution. Laser in situ keratomileusis (LASIK) is currently the most popular method for the correction of low to moderate ametropia.
Information about anterior segment inß ammatory changes aft er LASIK is limited. While anterior uveitis has been described as a complication of LASIK with an incidence of 0.18%, [1] most reported cases so far have been those of mild to moderate uveitis that respond well to topical medication. [1,2] We report a patient who developed severe anterior uveitis with Þ brinous exudates in one eye eight days aft er undergoing LASIK for low myopic astigmatism in both eyes.

Case Report
A 29-year-old woman underwent uncomplicated LASIK in both eyes for low myopic astigmatism. Prior systemic and ocular history was unremarkable. Preoperative refractive error was −3.00 diopter sphere (D Sph) / −1.00 diopter cylinder (D Cyl) × 180° in the right eye and −2.75 D Sph/ −1.00 D Cyl × 180° in the left eye. On her scheduled postoperative visits on Day 1 and 5, examination of both eyes revealed a clear cornea and a normal anterior segment with an uncorrected visual acuity of 20/20. Eight days aft er LASIK, the patient presented with severe pain, photophobia and decreased visual acuity in the left eye. Visual acuity at this time was 20/20 in the right eye and 20/80 in the left eye. Right eye examination was normal but the left eye showed mild ß ap edema, few peripheral epithelial bullae with intense ß are and cells in the anterior chamber with thick Þ brinous exudates in the anterior chamber. There were pigments on the endothelium and the anterior lens capsule but no keratic precipitates and the corneal stromal bed was clear. The intraocular pressure (IOP) was 11 mm Hg in the right eye and 9 mm Hg in the left eye. Posterior segment examination was normal in both eyes.
The patient was started on hourly prednisolone acetate 1% eye drops (Predmet ® eye drops, Sun Pharmaceuticals, India) and cyclopentolate 1% eye drops three times daily (Cyclate eye drops ® , Cadila Pharamceuticals, India). As systemic examination progressive mass with no pain. Due to its rarity and unusual location, eyelid schwannoma is frequently clinically confused with other diagnoses like chalazion [5] (our Case 2), or inclusion cyst. [8] To avoid eventual recurrence, surgical excision is indicated and has to be complete.
Pathologically, schwannomas classically show a mixture of two patt erns, the Antoni Type A densely cellular patt ern and the Antoni Type B edematous and disorganized patt ern.
The most important feature for diagnosis remains the strong reactivity to S100 protein in immunochemistry. [1][2][3][4][5][6][7] Negativity of tumor cells for HMB45 rules out the diagnosis of melanotic lesion. [1] The rare occurrence of eyelid schwannoma should be kept in mind in the diff erential diagnosis of any solid palpebral lesion, especially in case of recurrent chalazion.
When they are isolated, they are mostly benign. In neurofibromatosis they might rarely undergo malignant transformation. [1] by an internist proved unremarkable, a routine laboratory screen currently used at our hospital for patients with severe or recurrent anterior uveitis was ordered. This included blood counts, erythrocyte sedimentation rate (ESR), c-reactive protein, Mantoux test, venereal disease research laboratory test (VDRL), chest X-ray, human immunodeÞ ciency virus (HIV) serology and human leukocyte antigen (HLA) typing. These investigations were within normal limits and the patient was HLA B27-negative. As the patient failed to respond adequately aft er two days of topical steroid therapy with persistence of the uveitis, increase in Þ brinous exudates and development of early posterior synechiae [ Fig. 1], oral prednisolone 1 mg/kg body weight (Tab Wysolone ® , Wyeth Pharmaceuticals, India, 60 mg once daily) was added. The uveitis responded aft er starting oral steroids and gradually resolved over two weeks. At the end of two weeks, the uveitis had resolved with resolution of the ß ap edema and return of visual acuity to 20/20 [ Fig. 2]. Oral steroids were tapered and stopped over four weeks. Intraocular pressures remained normal throughout.

Discussion
Opinions vary regarding the eff ect of LASIK on anterior chamber inß ammatory response with some authors [3,4] reporting an altered blood-aqueous barrier and increase in aqueous ß are using a laser ß are meter while others have found no such changes. [5] In one large retrospective series, [1] the annual incidence of uveitis following LASIK was found to be 0.06%. Moshirfar et al. [6] found no diff erence in the incidence of uveitis in eyes undergoing LASIK and in the fellow eyes without LASIK among HLA B27-positive patients.
Several hypotheses have been put forward to explain uveitis after LASIK including the sudden increase and decrease of intraocular pressure following application of the suction ring which simulates the eff ects following a closed globe injury. [7] Another theory postulates that the shock wave following each excimer application incites inß ammation and that the depth of ablation correlates with the inß ammatory response. [4] This relation between ablation depth and inß ammatory response has not been demonstrated by other authors. [1] Our patient developed uveitis in one eye following ablation for nearly identical refractive error in both eyes suggesting that depth of ablation and number of laser spots do not correlate with the amount of inß ammation.
Nearly all the uveitis following LASIK reported in literature has been of the mild to moderate variety which responds rapidly to topical medication. Our patient developed a severe anterior uveitis with Þ brinous exudates that needed systemic steroids for control of inß ammation. This form of uveitis has not been reported earlier. The cause for this severe inß ammation in our patient is unclear. We perform LASIK in about 750 eyes annually and have not encountered any other case with anterior uveitis following LASIK. We believe the uveitis was related to the LASIK procedure as it developed within a short while of the surgery with no signiÞ cant history or systemic features and extensive laboratory investigations were normal. The patient was also negative for HLA B27 which is one of the frequent associations of Þ brinous anterior uveitis. It is possible that the uveitis in our patient could have been due to some other cause, such as a viral infection, which may have been missed during our lab screening. We currently encounter about 250-300 cases of uveitis annually at our hospital and in about 65% of cases of anterior uveitis, the etiology remains unclear.
In our patient, the ß ap edema developed despite normal IOP suggesting endothelial dysfunction associated with the severe inß ammation and pigment deposition. While endothelitis is not usual in anterior uveitis, ß ap edema and interface ß uid have been reported [2] as a cause of decreased visual acuity following uveitis. We believe that this could be due to a propensity for accumulation of ß uid at the ß ap interface with ß ap edema following uveitis in eyes that have undergone LASIK. In our patient, the stromal bed remained clear and the ß ap edema cleared well following resolution of the uveitis.
In conclusion, severe Þ brinous anterior uveitis may develop following LASIK and requires intensive treatment for resolution. LASIK surgeons should be aware of this potential complication.