A comparison of the potential acuity meter (PAM) and the illuminated near card (INC) in patients undergoing phacoemulsification.

PURPOSE: To compare the accuracy of the potential acuity meter (PAM) and the illuminated near card (INC) in patients undergoing phacoemulsification. METHODS: During presurgical evaluations, both PAM and INC were tested on each study patient following dilation. Patients then rated the subjective ease of use of each test. Best spectacle-corrected visual acuity (BSCVA) was recorded at 4 and 12 weeks postoperatively. McNemar's chi(2) test for paired associations was used to analyse categorical data; paired t-tests were used for continuous variables. RESULTS: Overall, the INC was more likely than the PAM to predict BSCVA within one Snellen line (P=0.002), but this difference decreased for accuracy within two lines. The PAM predicted BSCVA within one line in 87 (70.7%) eyes, as compared to 102 (82.9%) eyes by the INC. The PAM was accurate within two lines in 109 (88.6%) eyes; the INC was accurate in 115 (93.5%) eyes. The PAM was more likely to underpredict potential acuity (P<0.001), while the INC was more likely to overpredict (P=0.004) or give exact predictions of BSCVA (P<0.001). Accuracy of the INC declined in eyes with macular comorbidity. The PAM and INC were rated as 'easy' tests by 54 (45.4%) and 93 (78.2%) patients, respectively. CONCLUSIONS: Both the PAM and the INC were useful for predicting BSCVA after phacoemulsification, but the PAM was more likely to underestimate potential acuity. The INC was easier for patients to use, and had better accuracy than the PAM in patients without macular comorbidity, but was more likely to overestimate potential acuity.

Propionibacterium acnes as a cause of visually significant corneal ulcers.

PURPOSE: To report Propionibacterium acnes as a cause of vision-threatening infectious keratitis and to discuss culture isolation and antibiotic treatment. METHODS: Retrospective case series presentation collected from three academic medical centers. RESULTS: Six cases of P. acnes infectious keratitis are presented, all of which were associated with a compromised corneal barrier or environment. All cases were culture-positive on thioglycolate broth; none became positive before 7 days of growth. No other organisms were isolated from any culture, and the growth of P. acnes occurred in some cases despite negative gram stains. CONCLUSION: P. acnes can produce vision-debilitating keratitis when the cornea is compromised. Growth in culture should be monitored for at least 10 days to ensure isolation of this fastidious organism. P. acnes may respond to several different antibiotics that have gram-positive coverage, but it should be treated with vancomycin to enhance clearance of the organism.

Mutation hot spots in 5q31-linked corneal dystrophies.

Mutations in the BIGH3 gene on chromosome 5q31 cause four distinct autosomal dominant diseases of the human cornea: granular (Groenouw type I), Reis-Bücklers, lattice type I, and Avellino corneal dystrophies. All four diseases are characterized by both progressive accumulation of corneal deposits and eventual loss of vision. We have identified a specific recurrent missense mutation for each type of dystrophy, in 10 independently ascertained families. Genotype analysis with microsatellite markers surrounding the BIGH3 locus was performed in these 10 families and in 5 families reported previously. The affected haplotype could be determined in 10 of the 15 families and was different in each family. These data indicate that R555W, R124C, and R124H mutations occurred independently in several ethnic groups and that these mutations do not reflect a putative founder effect. Furthermore, this study confirms the specific importance of the R124 and R555 amino acids in the pathogenesis of autosomal dominant corneal dystrophies linked to 5q.

Intraocular metallic-appearing foreign bodies after phacoemulsification.

Intraocular metallic-appearing foreign bodies in the anterior segment were seen in six eyes after cataract extraction by two-handed phacoemulsification. These fragments produced no symptoms and had no clinically significant effect on visual function. Similar-appearing foreign bodies were experimentally produced by applying ultrasound power with a phacoemulsification handpiece to the surface of a cyclodialysis spatula in vitro. Microscopic examination of the phaco handpiece tip and cyclodialysis spatulas revealed numerous surface irregularities, suggesting a possible source of these fragments. These results suggest that instrument touch during phacoemulsification may be the cause of the fragments. Long-term follow-up of these patients is required to determine the overall effect of the fragments.

Objective measurement of corneal light scattering after excimer laser keratectomy.

PURPOSE: To obtain objective measurements of corneal light scattering after excimer laser keratectomy, and to evaluate the relation of light scattering to clinical haze grading and visual acuity. METHODS: The authors measured best-corrected visual acuity, subjective clinical haze grade, and corneal light-scattering index in patients undergoing photorefractive keratectomy (PRK) (n=26), and phototherapeutic keratectomy (n=8), preoperatively and postoperatively at 1,3,6,9, and 12 months or later. Corneal light scattering was correlated with visual acuity and clinical haze grade. RESULTS: Corneal light scattering increased after PRK and was reduced after phototherapeutic keratectomy. Corneal light scattering index showed a stronger positive correlation with logMAR visual acuity (r=0.57) than clinical haze grading (r=0.34). Corneal light-scattering index (P<0.05 at 1 and 3 months) and clinical haze grading (P<0.05 at 6, 9, and 12 months) were significantly higher in eyes undergoing PRK with ablation depths of more than 80 microns. CONCLUSIONS: Excimer laser surgery affects corneal light scattering. Ablations with depths greater than 80 microns produce significantly higher levels of haze than those less than 80 microns. Objective measurement of corneal light scattering may be useful in monitoring the outcome of excimer keratectomy.

Endoscopy and biopsy of the orbit.

Flexible endoscopes produce high-quality images, are small in size, and can deliver microsurgical instruments or laser probes. Early attempts at orbital endoscopy were limited by the relatively large size and poor visualization of rigid endoscopes. We performed endoscopic orbital exploration using the Olympus HYF flexible endoscope in four live dog orbits. We achieved excellent visualization of orbital structures including the globe, blood vessels, extraocular muscles, intermuscular septa, optic nerve, and fat. Visualization, hemostasis, and dissection were aided by the use of hyaluronic acid infused through the endoscope. We biopsied fat and extraocular muscle without complication using Olympus endoscopic cup biopsy forceps (confirmed by histopathologic examination). Our experience indicates that orbital endoscopy aided by viscoelastic hydrodissection may permit a less invasive approach to optic nerve sheath fenestration, tumor biopsy and treatment, and the removal of foreign bodies.

Ocular findings in cutaneous T-cell lymphoma.

Seventeen patients with cutaneous T-cell lymphoma undergoing an investigative treatment regimen using extracorporeal photochemotherapy underwent ophthalmologic examinations to investigate the ocular findings in this disease. The most frequent finding was seborrheic blepharoconjunctivitis, which was noted in 13 of 17 patients. Other common lid findings included cicatricial ectropion, meibomianitis, chalazia, and madarosis. Corneal and conjunctival disease was also increased in this group of patients. The syndrome of cutaneous T-cell lymphoma has recently been redefined, and a discussion of the revised concept of this disease is included. Previous studies used the old definition of this disease and were limited to the subgroups of mycosis fungoides and Sezary syndrome, which comprise only one third of the cutaneous T-cell lymphoma population.