Characteristics of Infectious Keratitis Associated with High Intraocular Pressure Elmira Baghdasaryan1,2, M.D. Sophie X. Deng1, M.D., Ph.D. Fei Yu1, Ph.D. 1 Jules Stein Eye Institute, University of California, Los Angeles 2Yerevan State Medical University after M. Heratsi Authors have no financial interest.

Background Infectious keratitis is an inflammation of the cornea caused by bacteria, fungi, protozoa or viruses. It is considered an ocular emergency and often associated with pain, photophobia, and redness. Prevalence of keratitis differs with geographical area, occupation, age, and even different seasons.1,2 In a number of developing countries, microbial keratitis is the second most common cause of preventable blindness after cataracts.3,4 1.Derek Y., Kunimoto S Sh, Prashant Gary, Usha G, et al. Corneal ulceration in the elderly in Hyderabad South India. Br. J ophthalmol 2000;84:54-59. 2. Schaefer Frederic, Olivier Bruttin, Zagrafos, Bacterial keratitis: A prospective cilical and microbiological study. B J Ophthalmology 2001; 85: 842-847. 3. Upadhyay MP, Karmacharya PC, Koirala S, et al. Epidemiologic characteristics, predisposing factors, and etiologic diagnosis of corneal ulceration in Nepal. Am J Ophthalmol 1991;111(1):92-9. 4. Gonzales CA, Srinivasan M, Whitcher JP, Smolin G. Incidence of corneal ulceration in Madurai district, South India. Ophthalmic Epidemiol 1996;3(3):159-66.

Purpose We conducted a retrospective study using a case-control design to describe the risk factors, clinical characteristics, outcomes, and microbiological profiles of acute infectious keratitis associated with high intraocular pressure (IOP).

Materials and Methods A retrospective chart review of 184 cases of culture-proven infectious keratitis was conducted at a single institution from January 2003 to December 2007. Fifty-two of these cases, which were associated with high IOP (K-IOP group), were compared to the other 132 cases without IOP elevation (control group). Elevated IOP was defined as IOP > 21 mm Hg. Resolution of the ulcer was defined as absence of the epithelial defect.

Risk Factors Risk factors that were studied include: Contact lens wear Prior ocular trauma Prior ocular surgery Diabetes Mellitus (DM) Neurotrophic keratopathy Exposure keratopathy Systemic immunosuppressants Systemic steroid use H/o glaucoma Age, sex, IOP data, rate of performed penetrating keratoplasties (PKP), evisceration, best corrected distance visual acuity (BCDVA), and microbiological profiles were also evaluated.

IOP Range for Both Groups IOP max (mm Hg) K – IOP group (n = 52) Control group (n = 132) Range 22 to 51 mm Hg 10 to 21 mm Hg Mean ± SD 29.1 ± 6.9 mm Hg 16.3±2.7 mm Hg Median 27.2 mm Hg 16 mm Hg a – Fisher exact test

Diabetes Mellitus (DM) Risk Factors Risk Factors K-IOP group (Total = 52) N (%) Control group (Total= 132) P-value a Diabetes Mellitus (DM) 15 (29%) 16 (12%) 0.009 H/o glaucoma 18 (14%) 0.02 Prior Ocular Surgery 32 (62%) 43 (33%) <0.001 Large Ulcer Size (≥4 mm) 34 (65%) 42 (32%) a – Fisher exact test

Neurotrophic Keratopathy Risk Factors Risk Factors K-IOP group (Total = 52) N (%) Control group (Total= 132) P-value a Contact Lens Wear 14 (27%) 62 (47%) 0.013 Neurotrophic Keratopathy 4 (8%) 16 (12%) 0.44 Exposure Keratopathy 9 (17%) 20 (15%) 0.82 Prior Trauma 0.23 Prior Steroid Use 11 (21%) 24 (18%) 0.68 a – Fisher exact test

Rate of Surgical Intervention K-IOP group Total=52 N (%) Control Group Total=132 P-value a Penetrating keratoplasty 15 (29%) 12 (9 %) 0.002 Evisceration 4 (8 %) 2 (2 %) 0.055 a – Fisher exact test

Visual Acuity Percentage of Patients VA at the last follow-up visit b VA at the initial presentation a VA at the last follow-up visit b a – p-value = 0.002 b- p-value=0.004

Results-Summary IOP elevation, ranging from 22 to 51 mm Hg (mean 29 mm Hg), occurred in 52 of 184 cases (28%) of microbial keratitis. Prior ocular surgery, DM, history of glaucoma, and large ulcer size (>4 mm) were significantly associated with IOP elevation during infection. The other risk factors were not significantly associated with IOP elevation. More patients achieved corrected VA of 20/40 or better at the last follow-up visit in the control group (49 %) than in the K-IOP group (23 %, p= 0.004). Furthermore, significantly more patients required PKP in the K-IOP group than in the control group (p=0.002).

Conclusions Elevated IOP was common, detected in 28% of patients with infectious keratitis. IOP elevation should be closely monitored during infection and treated. Patients with elevated IOP had poorer visual acuity and higher rates of penetrating keratoplasty and evisceration. Aggressive treatment should be done to reduce subsequent complications.