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Diffuse lamellar keratitis associated with Pseudomonas aeruginosa infection
CORRESPONDENCE
Diffuse lamellar keratitis associated with Pseudomonas aeruginosa infection Shannon G. Cox, Donald U. Stone, MD Diffuse lamellar keratitis (DLK) is an uncommon condition that can result in poor visual outcomes after laser in situ keratomileusis (LASIK).1,2 The etiology of DLK remains elusive, but Peters et al.3 were able to demonstrate DLK in rabbit models by exposing a LASIK flap to lipopolysaccharide endotoxin derived from Pseudomonas aeruginosa and bacterial endotoxins from sterilization equipment have been implicated in outbreaks of DLK.1 We report a case of DLK following a Pseudomonas corneal ulcer 5 years after LASIK. A 62-year-old woman was referred from an outside facility with microbial keratitis; she denied trauma to either eye or contact lens use. The ocular history was significant for LASIK vision correction 5 years previously. The best corrected visual acuity was 20/80 in the right eye. On examination, a midperipheral suppurative infiltrate with an overlying epithelial defect was observed. Scrapings for Gram stain, fungal stain, and cultures were taken; hourly vancomycin 50 mg/mL and tobramycin 14 mg/mL eyedrops were started. The following day, the vision in the right eye had decreased to finger counting; examination revealed an improving corneal ulcer and a new finding of DLK (Figure 1). The Gram stain demonstrated gram-negative rods, and topical prednisolone acetate 1% was started 4 times a day; the culture confirmed the diagnosis of Pseudomonas aeruginosa. Within 1 week, the midperipheral ulcer and DLK had resolved. It is not clear that Pseudomonas or endotoxin caused DLK in this patient,4 nor can we rule out the other proposed etiologies of DLK.5 However, this case lends support to the model of Pseudomonas endotoxin as a precipitating factor in the development of DLK.
Figure 1. Inferior corneal infiltrate with epithelial defect (source of Pseudomonas) (green arrow) and lamellar infiltrate with no epithelial defect (blue arrows). Q 2008 ASCRS and ESCRS Published by Elsevier Inc.
REFERENCES 1. Stulting RD, Randleman JB, Couser JM, Thompson KP. The epidemiology of diffuse lamellar keratitis. Cornea 2004; 23: 680–688 2. Hoffman RS, Fine IH, Packer M. Incidence and outcomes of LASIK with diffuse lamellar keratitis treated with topical and oral corticosteroids. J Cataract Refract Surg 2003; 29:451–456 3. Peters NT, Iskander NG, Anderson Penno EE, et al. Diffuse lamellar keratitis: isolation of endotoxin and demonstration of the inflammatory potential in a rabbit laser in situ keratomileusis model. J Cataract Refract Surg 2001; 27:917–923 4. Sharma N, Sinha R, Singhvi A, Tandon R. Pseudomonas keratitis after laser in situ keratomileusis. J Cataract Refract Surg 2006; 32:519–521 5. Chang-Godinich A, Steinert RF, Wu HK. Late occurrence of diffuse lamellar keratitis after laser in situ keratomileusis. Arch Ophthalmol 2001; 119:1074–1076
Near and intermediate visual acuity test Yian Jin Jones, MD, Jason J. Jones, MD Controlled observation is the key to a reliable clinical study. Data of all participants should be collected under the same conditions throughout the preoperative and postoperative testing. Regarding near and intermediate visual acuities, is the same distance used in preoperative and postoperative evaluation within a given article? Are near and intermediate acuities checked at the same distance in different studies? With the increasing use of premium intraocular lenses and with visual acuity becoming a primary outcome metric, the accurate and reproducible measurement of near and intermediate visual acuities has become more important. Near vision should be checked at a reading distance of 35 or 40 centimeters (14 or 16 inches) from the patient’s eyes and intermediate vision, at 70 or 80 centimeters (28 or 32 inches). How can we ensure the correct distance is used with each patient? We propose a simple and practical way to achieve this goal. Each person who checks visual acuity in the clinic should use 2 ‘‘yardstick’’ measurements: One from the tip of the middle finger, with fingers extended along the forearm to 14 or 16 inches, and the other from the tip of the middle finger to the acromion process at the edge of the shoulder, with the arm straight and the elbow fully extended. To check near visual acuity, extend the arm and place the middle finger tip in front of the patient’s eye while holding the chart at the previously measured near distance point. To check intermediate acuity, the distance has to be adjusted based on the measurement; eg, if the measurement of the arm length is 26 inches, add 2 or 6 inches to the length of the extended arm in front of the patient and place 0886-3350/08/$dsee front matter doi:10.1016/j.jcrs.2007.10.012
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Diffuse lamellar keratitis associated with Pseudomonas aeruginosa infection Shannon G. Cox, Donald U. Stone, MD Diffuse lamellar keratitis (DLK) is an uncommon condition that can result in poor visual outcomes after laser in situ keratomileusis (LASIK).1,2 The etiology of DLK remains elusive, but Peters et al.3 were able to demonstrate DLK in rabbit models by exposing a LASIK flap to lipopolysaccharide endotoxin derived from Pseudomonas aeruginosa and bacterial endotoxins from sterilization equipment have been implicated in outbreaks of DLK.1 We report a case of DLK following a Pseudomonas corneal ulcer 5 years after LASIK. A 62-year-old woman was referred from an outside facility with microbial keratitis; she denied trauma to either eye or contact lens use. The ocular history was significant for LASIK vision correction 5 years previously. The best corrected visual acuity was 20/80 in the right eye. On examination, a midperipheral suppurative infiltrate with an overlying epithelial defect was observed. Scrapings for Gram stain, fungal stain, and cultures were taken; hourly vancomycin 50 mg/mL and tobramycin 14 mg/mL eyedrops were started. The following day, the vision in the right eye had decreased to finger counting; examination revealed an improving corneal ulcer and a new finding of DLK (Figure 1). The Gram stain demonstrated gram-negative rods, and topical prednisolone acetate 1% was started 4 times a day; the culture confirmed the diagnosis of Pseudomonas aeruginosa. Within 1 week, the midperipheral ulcer and DLK had resolved. It is not clear that Pseudomonas or endotoxin caused DLK in this patient,4 nor can we rule out the other proposed etiologies of DLK.5 However, this case lends support to the model of Pseudomonas endotoxin as a precipitating factor in the development of DLK.
Figure 1. Inferior corneal infiltrate with epithelial defect (source of Pseudomonas) (green arrow) and lamellar infiltrate with no epithelial defect (blue arrows). Q 2008 ASCRS and ESCRS Published by Elsevier Inc.
REFERENCES 1. Stulting RD, Randleman JB, Couser JM, Thompson KP. The epidemiology of diffuse lamellar keratitis. Cornea 2004; 23: 680–688 2. Hoffman RS, Fine IH, Packer M. Incidence and outcomes of LASIK with diffuse lamellar keratitis treated with topical and oral corticosteroids. J Cataract Refract Surg 2003; 29:451–456 3. Peters NT, Iskander NG, Anderson Penno EE, et al. Diffuse lamellar keratitis: isolation of endotoxin and demonstration of the inflammatory potential in a rabbit laser in situ keratomileusis model. J Cataract Refract Surg 2001; 27:917–923 4. Sharma N, Sinha R, Singhvi A, Tandon R. Pseudomonas keratitis after laser in situ keratomileusis. J Cataract Refract Surg 2006; 32:519–521 5. Chang-Godinich A, Steinert RF, Wu HK. Late occurrence of diffuse lamellar keratitis after laser in situ keratomileusis. Arch Ophthalmol 2001; 119:1074–1076
Near and intermediate visual acuity test Yian Jin Jones, MD, Jason J. Jones, MD Controlled observation is the key to a reliable clinical study. Data of all participants should be collected under the same conditions throughout the preoperative and postoperative testing. Regarding near and intermediate visual acuities, is the same distance used in preoperative and postoperative evaluation within a given article? Are near and intermediate acuities checked at the same distance in different studies? With the increasing use of premium intraocular lenses and with visual acuity becoming a primary outcome metric, the accurate and reproducible measurement of near and intermediate visual acuities has become more important. Near vision should be checked at a reading distance of 35 or 40 centimeters (14 or 16 inches) from the patient’s eyes and intermediate vision, at 70 or 80 centimeters (28 or 32 inches). How can we ensure the correct distance is used with each patient? We propose a simple and practical way to achieve this goal. Each person who checks visual acuity in the clinic should use 2 ‘‘yardstick’’ measurements: One from the tip of the middle finger, with fingers extended along the forearm to 14 or 16 inches, and the other from the tip of the middle finger to the acromion process at the edge of the shoulder, with the arm straight and the elbow fully extended. To check near visual acuity, extend the arm and place the middle finger tip in front of the patient’s eye while holding the chart at the previously measured near distance point. To check intermediate acuity, the distance has to be adjusted based on the measurement; eg, if the measurement of the arm length is 26 inches, add 2 or 6 inches to the length of the extended arm in front of the patient and place 0886-3350/08/$dsee front matter doi:10.1016/j.jcrs.2007.10.012
337