Donald J. Doughman

National Outcomes of Cataract Extraction: Increased Risk of Retinal Complications Associated with Nd.-YAG Laser Capsulotomy

PURPOSE The authors studied 57,103 randomly selected Medicare beneficiaries who underwent extracapsular cataract extraction in 1986 or 1987 to determine the possible association between performance of neodymium (Nd):YAG laser capsulotomy and the risk of subsequent retinal break or detachment. METHODS Cases of cataract surgery were identified from Medicare claims submitted in 1986 and 1987 and were followed through the end of 1988. Episodes of cataract surgery, posterior capsulotomy, and retinal complications were ascertained based on procedure and diagnosis codes listed in physician bills and hospital discharge records. Lifetable and Coxs proportional hazards models were used to analyze the risk of retinal detachment or break in patients undergoing and not undergoing capsulotomy during the period of observation. RESULTS Of the 57,103 persons identified as having undergone extracapsular cataract extraction in 1986 or 1987, 13,709 subsequently underwent Nd:YAG laser capsulotomy between 1986 and 1988. A total of 337 persons had aphakic or pseudophakic retinal detachments between 1986 and 1988 and an additional 194 underwent repair of a retinal break. Proportional hazards modeling shows a 3.9-fold increase in the risk of retinal break or detachment among those who underwent capsulotomy (95% confidence interval: 2.89 to 5.25). Younger patient age, male sex, and white race also were associated with increased risk of retinal complications after extracapsular cataract extraction. CONCLUSION The authors conclude that there is a statistically significant increase in the risk of retinal detachment or break in those patients who undergo capsulotomy after cataract extraction. Therefore, capsulotomy should be deferred until the patients impairment caused by capsular opacification warrants the increased risk of retinal complications associated with performance of capsulotomy.

Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study One Year After Surgery

The Prospective Evaluation of Radial Keratotomy (PERK) study is a nine-center, self-controlled clinical trial of a standardized technique of radial keratotomy in 435 patients who had physiologic myopia with a preoperative refraction between -2.00 and -8.00 diopters. The surgical technique consisted of eight incisions using a diamond micrometer knife with blade length determined by intraoperative ultrasonic pachymetry and the diameter of central clear zone determined by preoperative refraction. At one year after surgery, myopia was reduced in all eyes; 60% were within +/- 1.00 diopter of emmetropia; 30% were undercorrected and 10% were overcorrected by more than 1.00 diopter (range of refraction, -4.25 to +3.38 D). Uncorrected visual acuity was 20/40 or better in 78% of eyes. The operation was most effective in eyes with a refraction between -2.00 and -4.25 diopters. Thirteen percent of patients lost one or two Snellen lines of best corrected visual acuity. However, all but three eyes could be corrected to 20/20. Ten percent of patients increased astigmatism more than 1.00 diopter. Disabling glare was not detected with a clinical glare tester, but three patients reduced their driving at night because of glare. Between six months and one year, the refraction changed by greater than 0.50 diopters in 19% of eyes.

Acanthamoeba Keratitis: A Growing Problem in Soft and Hard Contact Lens Wearers

Eleven contact lens-wearing patients presented with Acanthamoeba keratitis. Eight cases were culture- and/or stain-positive for Acanthamoeba and three were presumed to have Acanthamoeba keratitis based on history and clinical findings. Six wore daily wear soft contact lenses, two wore extended-wear soft contact lenses, one wore a polymethylmethacrylate hard contact lens, one wore a gas-permeable hard contact lens, and one wore a Saturn lens (combined hard and soft lens). Four patients used distilled water and salt tablet saline, three used tap water and salt tablet saline, two used tap water rinse, two used well water rinse or storage, and one used intravenous (IV) saline. It is apparent that all contact lens wearers are at some risk for Acanthamoeba keratitis developing if proper contact lens care is not maintained. Of great concern is the inability of most current chemical sterilization methods to kill the organism if the lens becomes contaminated. Heat disinfection will kill Acanthamoeba trophozoites and cysts but the lens must not be placed into contaminated solutions afterward. Prevention is very important because medical and surgical treatment failures are frequent. Eye care practitioners who fit contact lenses are advised to use heat disinfection for low-water content stock soft contact lenses, and to use hydrogen peroxide without a catalyst for a minimum of 6 hours for all other stock lens fitting sets, to specifically inquire about contact lens care habits used by their patients, and to discourage the use of homemade saline solutions.

Topical diclofenac in the treatment of ocular pain after excimer photorefractive keratectomy

BACKGROUND Following excimer laser photorefractive keratectomy, patients experience significant ocular pain until corneal reepithelialization. Despite the use of cold compresses, bandage soft contact lenses, cycloplegics, narcotics, and topical corticosteroids, the pain has not been adequately controlled in many patients. METHODS A randomized, double-masked, parallel-group study of diclofenac sodium 0.1% ophthalmic solution and its placebo vehicle was evaluated. Patients undergoing excimer myopic photorefractive keratectomy on their second eye were admitted overnight. Postoperative procedures included two drops of diclofenac or placebo immediately after surgery and then qid until reepithelialization, topical tobramycin (qid), 0.1% fluorometholone (q2h), cycloplegics, and a disposable soft contact lens. Thirty-two patients (diclofenac = 16, placebo = 16) were evaluated from +30 minutes to +96 hours by several types of questionnaires. RESULTS Most patients who received placebo experienced pain, starting within 1 hour, peaking at 4 to 6 hours and lasting 36 to 48 hours. The diclofenac-treated patients rarely experienced the early peak in pain, had less pain overall until 72 hours postoperatively, and experienced significantly less photophobia and burning/stinging. Significantly fewer patients on diclofenac required oral narcotics. Three patients (diclofenac = 2, placebo = 1) developed corneal infiltrates, the etiology of which is not known. In a separate study we conducted, there was no difference in epithelial healing times between the diclofenac-treated eyes and those not receiving the drug. CONCLUSIONS Diclofenac appears to significantly reduce the ocular pain following excimer photorefractive keratectomy.

Avellino Corneal Dystrophy: Clinical Manifestations and Natural History

PURPOSE The pathologic features of a variant of granular corneal dystrophy has been described in which the presence of lattice changes in addition to characteristic granular lesions has been documented. The authors investigated the mode of inheritance, natural history, and clinical manifestations of this dystrophy. METHODS A family with this condition was investigated, and a pedigree was established. Family members underwent ophthalmic examination, and ophthalmic history was obtained. In addition, pathologic examination of corneal tissue from affected patients was performed. RESULTS Similar to the four previously described cases, this family also traced its origins to Avellino, Italy. This autosomal dominant condition affected 27 of 92 family members, ranging in age from 5 to 77 years. Granular deposits were the earliest and most common manifestations. Lattice lesions were present in some patients with granular lesions. Older patients had anterior stromal haze between deposits, which impaired visual acuity. Recurrent granular deposits were noted in donor corneal tissue after penetrating keratoplasty for this condition. Pathologic examination of corneal tissue from affected patients confirmed the presence of hyaline material seen in granular dystrophy as well as fusiform deposits of amyloid, similar to those seen in lattice dystrophy type I. CONCLUSION This study establishes the natural history and clinical manifestations of this condition.

193-nm Excimer Photorefractive Keratectomy in High Myopia

PURPOSE To evaluate the refractive results of 193-nm excimer laser photorefractive keratectomy (PRK) performed on 48 highly myopic eyes in a multicenter study. METHODS A Visx 2015 or 2000 argon-fluoride excimer laser and a single-zone ablation technique were used. Postoperatively, eyes were treated with topical fluoromethalone for up to 5 months. Most eyes were treated with a 6.0- to 6.2-mm beam diameter after undercorrections and increased regression were noted with a 5.5-mm beam in earlier studies. Forty-eight eyes were treated for myopia, which was between -8.0 and -15.25 diopters (D) (spherical equivalent). The mean preoperative refraction was -11.2 D. Retreatment was performed after 6 to 16 months on 11 eyes for undercorrection. All eyes not retreated were followed for at least 12 months. RESULTS At 6 months, follow-up was available on 47 eyes. Of these eyes, 40% and 64% achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 60% of eyes attained 20/40 visual acuity or better uncorrected. Eleven patients (23%) were retreated between 6 to 16 months for undercorrection and/or regression. After retreatment, 47% and 81% of eyes achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 15% of eyes lost two lines of best-corrected visual acuity, and no eyes lost more than two lines. There was slightly more corneal haze seen in this group compared with the haze seen in patients undergoing PRK for low and moderate myopia. CONCLUSIONS These data show that excimer PRK can correct high amounts of myopia with reasonable stability after 6 months. Excimer PRK is an effective surgical treatment of severe myopia, but long-term follow-up is still needed to assess the stability of its effect.

The Use of Tissue Adhesive in Corneal Perforations

Eighty patients with either corneal perforation or impending perforation were treated with the application of tissue adhesive that remained in place on the average of 50 days. Forty-four percent of these cases healed with the application of glue alone. Complications occurred in nine patients (11%). Two developed marked increase in intraocular pressure that was controlled with antiglaucoma medications and seven developed corneal infiltrates. Five of the infiltrates were culture-proven bacterial infections occurring on the average of 73 days after gluing. The relationships between diagnosis, duration of glue, and complications are reviewed.

Penetrating Keratoplasty and Transscleral Fixation of Posterior Chamber Lens

We reviewed the outcome in 115 patients who underwent penetrating keratoplasty and transscleral fixation of a posterior chamber lens. One patient died soon after surgical procedures, and nine patients were lost to follow-up, leaving a cohort of 105 patients. Mean follow-up time was 26.8 months (range, six to 43 months). Visual acuity of 20/40 or better was found in 29 patients (27.6%) and 20/50 to 20/200 in 37 patients (35.2%). Reasons for poor visual outcome included cystoid macular edema in ten patients (9.5%), age-related macular degeneration in six patients (5.7%), and retinal detachment in four patients (3.8%). None of the patients developed lens decentration. There were no instances of hyphema and only one patient had a perioperative limited suprachoroidal hemorrhage. New-onset increase in intraocular pressure developed in 20 of 66 patients (30.3%). Analysis of the 39 patients with preoperative increase in intraocular pressure that required medical treatment demonstrated an improvement in 13 patients (33.3%), worsening in 12 patients (30.8%), and unchanged status in 14 patients (35.9%). The exposed haptic suture was covered by using one of the following three alternative methods: a conjunctival flap, a scleral flap, or a corneal tissue button. Exposure of the haptic suture through the conjunctiva was a complication in 21 patients (20%). Of these 16 (76.1%) occurred in the group with a conjunctival covering, five (23.8%) occurred in the group with a scleral flap, and none occurred in the corneal tissue button group. This study demonstrated that transscleral fixation of a posterior chamber lens is a viable option in the treatment of patients undergoing penetrating keratoplasty and intraocular lens implantation with absent capsular support.

Three-year Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study

The Prospective Evaluation of Radial Keratotomy (PERK) study is a nine-center clinical trial of a standardized technique of radial keratotomy in 435 patients who had simple myopia with a preoperative refractive error between -2.00 and -8.00 diopters (D). We report results for one eye of each patient. The surgical technique consisted of eight incisions using a diamond micrometer knife with the blade length determined by intraoperative ultrasonic pachymetry and the diameter of the central clear zone determined by the preoperative refractive error. At three years after surgery, 58% of eyes had refractive error within one diopter of emmetropia; 26% were undercorrected, and 16% were overcorrected by more than one diopter. Uncorrected visual acuity was 20/40 or better in 76% of eyes. The operation was more effective in eyes with a preoperative refractive error between -2.00 and -4.37 diopters. Between one and three years after surgery, the refractive error changed by 1.00 diopter or more in 12% of eyes, indicating a lack of stability in some eyes.

Results One Year After Using the 193-nm Excimer Laser for Photorefractive Keratectomy in Mild to Moderate Myopia

As part of a clinical trial, photorefractive keratectomy using the VISX 2015 193-nm excimer laser was performed on 91 healthy eyes of 91 patients. Preoperative refractive errors (spherical equivalent) ranged from -1.00 to -7.50 diopters (mean, -4.16 +/- 1.41 diopters). No patient had more than 1 diopter of refractive astigmatism. Six months postoperatively, the average residual refractive error was +0.09 +/- 0.63 diopters (range, -2.13 to +1.63 diopters). Correction within 1 diopter of that attempted was attained in 85 eyes (93%). Uncorrected visual acuity of 20/40 or better was attained in 86 eyes (95%) and was 20/25 or better in 67 eyes (74%). At one year, follow-up information was available on 85 eyes of 85 patients. The average residual refractive error was -0.15 +/- 0.65 diopters (range, -2.50 to +1.63 diopters). Correction within 1 diopter of that attempted was attained in 85 eyes (93%). Uncorrected visual acuity was 20/40 or better in 83 eyes (98%) and was 20/25 or better in 68 eyes (80%). One patient lost three lines of best-corrected visual acuity because of corneal haze, dropping from 20/15 to 20/30, whereas all other patients returned to best-corrected visual acuity within one line of their preoperative best-corrected visual acuity. Photorefractive keratectomy with the 193-nm excimer laser appears to be a useful treatment modality for the reduction of mild to moderate myopia.