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Biomedical subjects

Claes H Dohlman

Publications and source records attributed to Claes H Dohlman.

11 recordsLinked to original sources

Fungal colonization and infection in Boston keratoprosthesis.

PURPOSE: To determine the incidence of and risk factors for fungal keratitis and endophthalmitis in patients with a Boston keratoprosthesis (KPro) and to determine whether surveillance cultures were helpful in predicting fungal infection. METHODS: A retrospective chart review was performed of 182 patients (202 eyes) who received a type 1 (through cornea) or type 2 (through cornea and lid) KPro between March 1, 1990, and December 31, 2004, and who were followed for at least 1 month (range, 1 month to 13 years; mean, 2.84 years). There were 148 eyes with type 1 and 54 eyes with type 2. Beginning in late 1999, many eyes were given a prophylactic topical regimen containing vancomycin, and many eyes with type 1 KPro were given therapeutic contact lenses. Cases of fungal keratitis or endophthalmitis were analyzed. To determine the fungal colonization rate, 70 surveillance cultures of the ocular or lid surface around the KPro optic were obtained of 36 uninfected KPro eyes (35 patients) at random time-points over 1 year (August 2002 to July 2003). RESULTS: There were 4 definite and 1 probable fungal infections in 6893 patient-months of follow-up, or 0.009 fungal infections per patient-year. These included 3 cases of definite or probable Candida endophthalmitis (C. parapsilosis, C. glabrata, and C. albicans) and 2 cases of mold keratitis (Alternaria, Fusarium). The rate was higher in eyes receiving a vancomycin-containing topical prophylactic regimen than those with on a non-vancomycin regimen (5 cases/2774 person-months vs. 0 cases/4119 person-months; P = 0.011). In eyes with type 1 KPro, the rate was higher with therapeutic contact lens wear than without (4/1682 vs. 0/3115 person-months; P = 0.015). Surveillance cultures did not predict fungal infection, and none of the 6 surveillance eyes colonized with fungi (all Candida) developed a fungal infection. The prevalence of fungal colonization in KPro eyes had not changed since our 1996 surveillance study (11% vs. 10%, P > 0.05). CONCLUSION: Fungal infections in KPro eyes have appeared since we introduced broad-spectrum antibiotic prophylaxis and therapeutic contact lenses 5 years ago, but the infection rate remains very low in our mostly New England-based patient population. Cleaning or replacing the contact lens on a regular basis and prescribing a short course of topical amphotericin at the first visible signs of fungal colonization may prevent these infections.

Adult↗

Sudden reversible vitritis after keratoprosthesis: an immune phenomenon?

PURPOSE: To report our experience with late vitritis associated with keratoprosthesis (KPro). METHODS: Between 1990 and 2003, 218 patients underwent an all-polymethylmethacrylate, collar button-shaped KPro surgery. Eight patients developed a total of 12 episodes of sudden, massive vitritis. Five of these patients had an Ahmed shunt implant, 3 had anterior vitrectomy during surgery, and 4 had a soft contact lens in place. Preoperative diagnoses were multiple graft failures, chemical burn, Stevens-Johnson syndrome, or ocular cicatricial pemphigoid. All patients were maintained on prophylactic topical ofloxacin 0.3% or polymyxin-B/trimethoprim, as well as prednisolone acetate 1% (in 2 cases, medroxyprogesterone 1%), at least twice daily. Vancomycin (14 mg/mL) was also given twice daily in 2 patients. RESULTS: Vitritis occurred in 8 patients (12 episodes), 2 to 23 months postoperatively. All patients presented with sudden, very marked decrease in vision, with little or no pain, tenderness, conjunctival redness, or discharge. Eight of the 12 events were subjected to vitreous tap and injection of antibiotics and steroids on the day of presentation. Cultures grew Staphylococcus epidermidis, only in liquid (broth) media, in 3 cases; the other 5 showed no growth. The vitritis episodes resolved after 2 to 9 weeks. Full recovery to pre-episode status of a quiet eye with clear vitreous was seen in all patients. Visual acuity recovered almost completely or completely (mental debilitation in one patient made accurate assessment uncertain). CONCLUSIONS: This phenomenon of sudden vitritis after KPro, with few other symptoms and with complete recovery, would be uncharacteristic of a bacterial endophthalmitis. It may represent a uveitic immune phenomenon.

Anti-Bacterial Agents↗

Corneal oedema in ocular hypotony.

We describe the pattern of corneal oedema observed in five patients with chronic hypotony. The patients had marked stromal oedema from presumed endothelial dysfunction, but no epithelial oedema. These observations corroborate the concept that the intraocular pressure is the driving force in the generation of epithelial oedema.

Adult↗

Oculoplastic technique of connecting a glaucoma valve shunt to extraorbital locations in cases of severe glaucoma.

PURPOSE: To describe a technique for inserting glaucoma shunts to the sinuses or the lacrimal sac as a means of lowering intraocular pressure in patients with refractory glaucoma associated with severe ocular surface disease. METHODS: Nineteen patients with severe ocular surface disease necessitating a keratoprosthesis and with intractable glaucoma underwent placement of a modified Ahmed shunt to direct aqueous in the maxillary or ethmoid sinus or lacrimal sac. RESULTS: Intraocular pressure is presently well controlled without glaucoma medications in two thirds of patients. None of the patients had endophthalmitis. CONCLUSIONS: Established oculoplastic surgery techniques may be used to redirect aqueous to extraorbital locations and effectively lower intraocular pressure in patients with severe ocular surface disease and refractory glaucoma. This procedure has not been associated with endophthalmitis.

Cornea↗

Management of vitreoretinal complications in eyes with permanent keratoprosthesis.

OBJECTIVES: To evaluate the spectrum and treatment of posterior segment complications in eyes that had undergone successful keratoprosthesis (KPro) placement and to determine whether transeyelid vitrectomy techniques could be effectively used in eyes otherwise vulnerable to surface exposure. DESIGN: In the last 10 years, 110 patients received a Dohlman-Doane KPro at the Massachusetts Eye and Ear Infirmary, Boston. We evaluated 22 eyes in 18 patients that required subsequent vitreoretinal surgery to treat posterior segment complications. One surgeon using modified vitreoretinal techniques, as described below, performed all vitreoretinal procedures. RESULTS: The posterior segment complications included 6 cases of retro-KPro membranes, 13 cases of retinal detachments, and 5 cases of isolated vitreous opacity. All 6 retro-KPro membranes were effectively removed by vitrectomy without significant complication and 3 of these patients enjoyed improvement of visual acuity of at least 5 Snellen lines. Of 13 cases of retinal detachment, 6 patients had some improvement in visual acuity, 5 showed no appreciable change, and 2 had some decline in the final visual acuity. In all 5 cases of isolated vitreous opacity, the media was effectively cleared with pars plana vitrectomy. Three patients enjoyed improvement of visual acuity of at least 3 Snellen lines. Four cases of transeyelid vitrectomy were attempted and anatomical success was achieved in all 4 and vision improved in 3 of these patients. No special surgical complications were encountered in any of the 22 eyes as a result of these modified surgical techniques. MAIN OUTCOME MEASURES: Best preoperative and postoperative visual acuity and anatomical success were evaluated in relation to the preoperative posterior segment complication. CONCLUSIONS: Modified vitreoretinal surgical techniques can be effectively and safely used to treat posterior segment complications in patients with KPro devices. Retro-KPro membranes and other vitreous opacities were the most amenable to treatment. Retinal complications posed a special challenge. However, all of these cases highlight that modified vitrectomy techniques can be used in eyes with permanent KPro devices. These techniques can be performed without additional risk to the eye. Additionally, we demonstrated that transeyelid vitrectomy techniques could be used effectively to manage complications in eyes with severe ocular surface disease without undue exposure of vulnerable tissues.

Adult↗

Mechanisms of corneal ulceration.

Corneal ulceration is a significant cause of visual morbidity. Although this discussion has primarily focused on the local factors involved in non-immune related sterile corneal ulcerations, an understanding of these mechanisms is important since a final common pathway that is conceivably relevant to all forms of corneal ulceration exists. With respect to the treatment of chronic sterile ulcerations, our contemporary armamentarium is extensive; an acknowledgement to the inadequacies of any single strategy. A sound appreciation of the subtleties involved in the pathogenesis of corneal ulceration and the orchestration of wound repair will lead us towards more effective strategies to decrease inflammation associated with ulceration, promote corneal wound healing, and ultimately provide better care for our patients.

Cornea↗

Protection of the ocular surface after keratoprosthesis surgery: the role of soft contact lenses.

PURPOSE: To evaluate the short-term therapeutic value of soft contact lenses in patients with keratoprosthesis. METHODS: Nineteen patients with a collar button-shaped keratoprosthesis were fitted with a soft contract lens and evaluated for the protective effect on the surrounding cornea. RESULTS: The lenses were found to be highly protective against evaporative damage to the corneal surface around the device. They were well tolerated and could remain clean and in place for months. One infection occurred. CONCLUSION: A soft contact lens can be of considerable protective value to the cornea surrounding a keratoprosthesis.

Contact Lenses, Hydrophilic↗