M. Bowes Hamill

Fungal keratitis in contact lens wearers

In a retrospective review from 1972 through 1987 of patients with microbial keratitis, fungal infection occurred in four (4%) of 90 cosmetic or aphakic contact lens wearers and in four (27%) of 15 patients using a therapeutic soft contact lens. Predisposing factors included improper lens care by the refractive lens wearers and a chronic epithelial defect with topical corticosteroid use among the therapeutic lens wearers. The responsible organisms in the refractive lens group were Fusarium solani (two patients) and Cephalosporium and Paecilomyces (one patient each), and in the therapeutic lens group Candida (three patients) and Aspergillus (one patient). Filamentous fungi were more likely to be associated with cosmetic or aphakic lens wear, whereas yeasts were more frequently found with therapeutic lens use.

Bacterial Keratitis after Radial Keratotomy

The authors identified nine patients with culture-proven keratitis after radial keratotomy (RK). Three patients became infected in the immediate post-operative period, and six patients had delayed-onset keratitis. Gram-negative rods were the predominant pathogens in late-onset keratitis (4 of 6 infections). Gram-positive cocci were implicated in all three postoperative infections. The inferior corneal quadrants were involved in seven of nine patients. Two episodes of late-onset keratitis were associated with contact lens wear. Five of these patients had transverse incisions or greater than eight radial cuts. All six patients regained visual acuity of 20/40 or better. Two additional cases of early-onset and six cases of late-onset keratitis with many features similar to these cases have been reported previously.

Epithelial healing and ocular discomfort after photorefractive keratectomy in children

Objective: To document the rate of healing of the corneal epithelial defect created by photorefractive keratectomy (PRK) and the degree of discomfort experienced by children treated with PRK. Setting: Baylor College of Medicine, Texas Childrens Hospital, Houston, Texas, USA. Methods: Ten patients between 3 and 10 years of age were treated with PRK for severe anisometropia. All had anisometropic amblyopia refractory to conventional therapy with glasses or contact lenses and occlusion therapy. The size of the corneal epithelial defect was documented daily until the defect healed completely. Postoperative discomfort was documented daily using a pain‐assessment scale until the epithelial defect healed completely. Results: Two children were treated with PRK for hyperopic anisometropia; the rest were treated for myopic anisometropia. Cumulatively, the corneal epithelium had healed completely by day 3 in 6 patients (60%), by day 4 in 9 patients (90%), and by day 5 in all patients. The mean healing time was 3.5 days. Patients experienced mild discomfort on the day of surgery and on the first postoperative day. They had minimal pain on day 2. After day 2, no patient reported pain or other discomfort. Conclusion: The corneal epithelial defect created by PRK healed promptly and was associated with minimal postoperative discomfort in children treated with the protocol described.

Descemet's stripping endothelial keratoplasty under topical anesthesia

&NA; We describe a technique for performing Descemets stripping endothelial keratoplasty under topical anesthesia and report the results in 7 patients. No patient reported intraoperative discomfort, and no operative complications were noted. Using a topical anesthetic approach in appropriate patients eliminates the risks associated with retrobulbar and peribulbar blocks.

Varicella Disciform Stromal Keratitis

We treated five patients, aged 26, 4, 6, 13, and 7 years, who developed disciform stromal keratitis one, four, four, eight, and ten weeks, respectively, after the onset of the acute vesicular exanthema. Serologic testing confirmed recent varicella and excluded other infectious causes in two cases. After initial improvement with a topical corticosteroid, three patients developed recurrent corneal inflammation resembling zoster keratitis. These cases and previous reports indicate that varicella-zoster virus is a cause of disciform stromal keratitis that may occur and recur several weeks or months after the primary skin rash has resolved.

Successful implementation of a protocol for photorefractive keratectomy in children requiring anesthesia

Purpose: To describe a protocol for treating children with photorefractive keratectomy (PRK) under general anesthesia and to review intraoperative and postoperative complications. Setting: Institutional academic practice. Methods: Nine patients between 3 years and 9 years of age were treated with PRK under general anesthesia for anisometropia with unilateral high myopia or high hyperopia and amblyopia of the affected eye. Induction of anesthesia and the surgical procedure were carried out in separate rooms. The laser beam was centered on the entrance pupil, and eye position was monitored throughout the procedure. Specific precautions were taken before and during the procedure to prevent unwanted effects of inhalational anesthetic agents on laser performance. Results: All children did well, with no anesthesia‐related or treatment‐related complications. Conclusions: Our protocol for PRK under general anesthesia was effective and efficient in children who were unable to cooperate for the procedure using local anesthesia. It can be adapted for laser in situ keratomileusis and other refractive surgical procedures in children and uncooperative adults.

Iris-sutured intraocular lenses for ectopia lentis in children

PURPOSE: To compare outcomes and complications of pars plana lensectomy–vitrectomy (PPL–PPV) for the management of ectopia lentis in children with and without a foldable iris‐sutured intraocular lens (IOL). SETTING: Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA. METHODS: This study comprised 22 eyes of 12 consecutive pediatric patients with ectopia lentis who had PPL–PPV by the same vitreoretinal surgeon with (12 eyes; Group L) or without (10 eyes; Group A) insertion of a foldable iris‐sutured IOL between June 1998 and October 2006. Outcome measures included the proportion of eyes achieving visual acuity of 20/40 or better, mean logMAR visual acuity, and complications. RESULTS: There was no statistically significant difference between the 2 groups in the proportion of eyes achieving a visual acuity of 20/40 or better (Group A: 5/10; Group L: 10/12) (P = .17) or the mean postoperative best corrected logMAR visual acuity (Group A: 0.41 [20/52]; Group L: 0.24 [20/35]) (P = .18). Complications included IOL dislocation in 4 (33%) of 12 eyes in Group L (95% confidence interval, 11%‐65%). Eyes with dislocated IOLs had retrieval with resuturing of the IOL to the iris and had a mean visual acuity of 20/27 at the last follow‐up. No retinal detachment was observed. CONCLUSION: Pars plana lensectomy–vitrectomy with iris‐fixation of a foldable IOL for the management of ectopia lentis yielded visual outcomes as least as good as those of optically corrected aphakia with a significant risk for dislocation.

Bilateral Acanthamoeba Keratitis

PURPOSE To determine the prevalence and characteristics of binocular involvement among patients with Acanthamoeba keratitis. DESIGN Retrospective case series. METHODS Risk factors and outcomes of bilateral infection were explored among consecutive cases of Acanthamoeba keratitis diagnosed at a single institution from 1997 through mid 2007. RESULTS Fifty eyes were confirmed to have Acanthamoeba keratitis by microbiologic or histopathologic testing; two-thirds occurred during a regional outbreak beginning in 2004. Five (11%) of 45 patients had infection of both eyes, including three with concurrent involvement and two with successive disease of the contralateral cornea. Three binocularly infected patients used soft contact lenses, and two wore rigid gas-permeable lenses. Nine of 10 eyes achieved visual acuity of 20/30 or better after antiamebic therapy. CONCLUSIONS Bilateral Acanthamoeba keratitis is an infectious complication of contact lens wear. With laboratory confirmation, vision often can be restored with medical therapy.

Scanning electron microscopic evaluation of the surface characteristics of 4 microkeratome systems in human corneas

Purpose: To evaluate the surface characteristics of keratectomy specimens created with 4 microkeratomes by scanning electron microscopy (SEM). Setting: Two university institutions. Methods: Keratectomies were performed in 10 fresh, unfrozen human eyes with 1 of 4 microkeratomes: the Draeger rotary microkeratome (Storz Instruments), the Universalkeratome® (Phoenix), the Automated Corneal Shaper® (Bausch & Lomb), or the Hansatome® (Bausch & Lomb). The beds and edges of the keratectomy specimens were then examined by SEM. Standardized photographs were taken, and the surface and cut‐edge characteristics of the keratectomies were compared. Results: Irregularities were noted in the cut edges of Bowmans membrane and the surface of the keratectomy beds with all instruments. The irregularities were most prominent in corneas cut with the Draeger instrument and least prominent in those cut with the Universalkeratome. The serrations in Bowmans membrane and the irregularities in the keratectomy bed appeared to be related to the blade movement in oscillating blade instruments. Conclusions: All 4 microkeratomes caused some degree of surface irregularity. The Draeger microkeratome, which uses a continuously rotating blade, resulted in the greatest number of Bowmans membrane serrations and irregularities in the keratectomy bed. The tissue irregularities may be related to the development of pressure ridges ahead of the blade. In instruments that use an oscillating blade, chatter marks appear to be related to the reciprocating movement of the blade as it travels across the corneal stroma.

Laser in situ keratomileusis flap suturing to treat recalcitrant flap striae

Purpose: To describe the management of resistant laser in situ keratomileusis (LASIK) flap striae using interrupted sutures. Setting: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. Methods: Interrupted sutures were used to treat striae in the LASIK flaps in 7 eyes of 7 patients. The mean interval from LASIK to the time of suturing was 11.8 months (range 3.0 to 29.0 months). The preoperative best spectacle‐corrected visual acuity (BSCVA) was 20/20–2 to 20/100. All patients had subjective visual complaints with spectacle correction, and all corneas had obvious macrostriae on slitlamp biomicroscopic examination. Results: The mean patient follow‐up was 7.0 months (range 1.5 to 14.0 months). Six patients regained a BSCVA of 20/20 or better with resolution of preoperative irregular astigmatism and subjective visual disturbance. In 1 patient, mild central striae recurred. Conclusion: Flap suturing was an effective means of treating visually significant flap striae.