Intrastromal corneal ring segments for low myopia: a report by the American Academy of Ophthalmology.

OBJECTIVE: This document describes intrastromal corneal ring segments (Intacs) inserts technology and examines the evidence to answer the key question about whether the treatment is safe and effective in correcting low myopia. METHODS: A literature search that was conducted in September 2000 retrieved 13 relevant citations, and the reference lists of these articles were consulted for additional citations. Panel members reviewed this information and articles were rated according to the strength of evidence. RESULTS: Prospective multicenter phase II and III clinical trials (Level II evidence rating) of Intacs inserts for myopia of -1.00 to -3.00 diopters (D), with a maximum of +1.00 D of astigmatism, enrolled a total of 452 subjects, with a total of 454 surgical attempts. The results from phase II and phase III were pooled for much of the analysis. At 1 year, 97% of patients who completed follow-up had 20/40 or better uncorrected visual acuity (UCVA). Seventy-four percent of patients had 20/20 or better UCVA. Ninety-two percent of eyes were within +/-1 D of intended refractive correction, and 69% were within 0.5 D of intended refractive correction. At 3 months, 90% of patients had less than 1.0 D of change from the previous examination performed at 1 month. The ocular complication rate, which was defined as clinically significant events but not resulting in permanent sequelae, was 11% at 12 months. The adverse event rate was 1.1%, defined as a serious event if untreated. Nearly 9% of patients requested to have their inserts removed and a total of 3.8% of patients required a secondary surgical intervention. CONCLUSIONS: To date, evidence suggests that low myopia (-1 to -3 D) in a well-defined group of patients who have a stable manifest refraction and less than +1.0 D of astigmatism can be treated with Intacs inserts with a reasonable assurance of safety and effectiveness. Additional clinical research is needed to determine the long-term effectiveness of treatment and the comparative safety, effectiveness, and costs with other treatment modalities, including laser-assisted in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).

Bacterial endophthalmitis following cataract surgery in an eye with a preexisting Molteno implant.

We describe a patient with a preexisting, functioning Molteno implant in whom acute endophthalmitis developed following cataract extraction. The condition was treated successfully without removing the implant.

Conjunctival involvement in paraneoplastic pemphigus.

Paraneoplastic pemphigus is a recently described autoimmune inflammatory mucocutaneous disease associated with an underlying neoplasm. Although histopathologic and direct immunofluorescence findings of involved skin and mucous membranes are consistent with pemphigus vulgaris, indirect immunofluorescence and immunoprecipitation study results are unique. We treated two patients with non-Hodgkin's lymphoma and paraneoplastic pemphigus. Both patients had bilateral bulbar conjunctival hyperemia and diffuse papillary tarsal conjunctival reactions. One patient had sloughing of conjunctival epithelium and the other had tarsal conjunctival cicatrization and forniceal shortening. Histopathologic findings of conjunctivae obtained from both patients were consistent with pemphigus vulgaris. Diffuse deposition of IgG and C3 in the intercellular substance of the conjunctival epithelium was demonstrated by direct immunofluorescence. Indirect immunofluorescence testing disclosed binding of autoantibodies to rodent bladder and intestinal epithelium. Immunoprecipitation disclosed antibodies reactive to Desmoplakin I (250 kd), bullous pemphigoid (230 kd), Desmoplakin II (210 kd) and 190-kd proteins. Ophthalmologists and pathologists should be aware of the conjunctival changes in paraneoplastic pemphigus.

Complications of penetrating keratoplasty: graft infections.

Microbial infection of a corneal transplant is a complication that is a bane to all corneal surgeons, the sequelae of which can be devastating. Identified risk factors include exposed, loose, or broken sutures; persistent epithelial defects or severe punctate keratopathy; soft contact lens wear including therapeutic lenses; graft hypoesthesia; kerato-conjunctivitis sicca; previous herpetic eye disease; graft failure; ocular adnexa and lid abnormalities; and ongoing external and corneal infections. Management includes preventive measures, microbiologic diagnostic procedures, and antibiotic therapy. Infectious crystalline keratopathy is a unique corneal infection that predominantly occurs in corneal transplants. It is characterized by the slowly progressive development of needle-like opacities in the corneal stroma and is most commonly caused by streptococcal species. Another group of infections that occur in grafts is recurrence of an infectious process for which the patient was originally grafted. Two notable pathogens in this group include Acanthamoeba and herpes simplex.

Hibiclens keratopathy. A clinicopathologic case report.

A 39-year-old woman developed a painful, red eye immediately following oral surgery associated with preoperative preparation of her face with the antiseptic, Hibiclens. Epithelial and stromal edema was observed 2 weeks after surgery and progressed to diffuse bullous keratopathy. This led to penetrating keratoplasty 10 months later. Light and electron microscopic findings of the cornea included epithelial edema with bullous changes, marked loss of keratocytes, a thickened Descemet's membrane, and an attenuated, disrupted endothelial cell layer. These findings demonstrate the corneal damage that may occur following ocular exposure to Hibiclens.

The results of penetrating keratoplasty for pellucid marginal corneal degeneration.

Over a 14-year period from 1974 to 1988, 12 eyes of 11 patients with pellucid marginal corneal degeneration underwent penetrating keratoplasty. Peripheral corneal thinning required a large eccentric graft in each case. Follow-up ranged from one to eight years (mean, three years). One graft failed because of a persistent epithelial defect with keratolysis of the wound. Although endothelial allograft rejection was common, occurring in seven of 11 (64%) clear grafts, no graft failed because of rejection. Other complications included retinal detachment and a bacterial corneal ulcer. Suture erosion and vascularization of the graft were not problems. Postoperative spectacle correction was dispensed an average of 11 months after surgery. Visual acuity in seven patients without amblyopia, retinal disease, or a previous corneal ulcer at the time of spectacle correction ranged from 20/20 to 20/40 (mean, 20/30). Average final keratometric astigmatism in these patients was 2.46 diopters (range, 0.00 to 5.25 diopters). We believe that penetrating keratoplasty offers an excellent surgical result for patients with pellucid marginal corneal degeneration.

Development of keratoconus after contact lens wear. Patient characteristics.

A retrospective review of 398 eyes of 199 patients with keratoconus revealed 106 eyes of 53 patients with an association between contact lens wear and the development of keratoconus. The absence of keratoconus at the time of contact lens fitting was confirmed by slit-lamp examination, keratometry readings, and manifest refraction. Keratoconus was diagnosed after a mean of 12.2 years of contact lens wear. This group was compared with patients with sporadic keratoconus with either no history of contact lens wear or a history of contact lens wear after the diagnosis. They were older at the time of diagnosis, had central vs decentered cones, and had a tendency toward flatter corneal curvatures. We believe that these patients suggest that long-term contact lens wear is a factor that can lead to keratoconus.

Ring stromal opacity in lens-corneal adhesion.

Severe congenital corneal clouding may be associated with abnormal anterior segment development (dysgenesis). Often, congenital corneal opacities preclude visualization of intraocular anatomy. In this report, five eyes of four patients with congenital corneal clouding and lens-corneal adhesion (LCA) are described. All had a ring- or doughnut-shaped haze within the stroma surrounding a central clear corneal zone delineating the adhesion. Recognition of LCA is pivotal in planning surgical therapy for eyes with congenital corneal clouding. As a clue to recognition of this anomaly, the ring-shaped stromal opacity may aid in diagnosis of this phenomenon and in avoidance of surgical complications.

Classification of corneal endothelial disorders based on neural crest origin.

The corneal endothelium is derived from the neural crest. A general classification of disorders of development of the neural crest has been previously presented (Johnston). Disorders of the corneal endothelium may be considered according to a modification of this scheme to reflect its true embryologic origin. In this classification, corneal endothelial disorders are categorized as abnormalities of neural crest cell formation (cyclopia), migration (Peters' anomaly), proliferation (iridocorneal endothelial syndrome), final differentiation (Fuchs' dystrophy), and acquired abnormalities (metaplasia, abiatrophy, and proliferation).