A comparison of Nd:YAG laser damage thresholds for PMMA and silicone intraocular lenses.

Power density producing damage at a probability of 0.5 (ie, damage threshold, DT-50) was determined for PMMA (with/without UV absorber) and Silicone intraocular lenses. Scattered light from a collinear diagnostic He:Ne beam was one of four damage monitors deployed to enhance the sensitivity of the system. In order of increasing laser resistance the following results were obtained: injection molded PMMA (1.9/GW/cm2) Silicone (2.63 GW/cm2) Lathe-cut PMMA (4.47 GW/cm2), Lathe-cut PMMA with UV absorber (8.32 GW/cm2), Cast-molded PMMA (12.30 GW/cm2). An analysis of variance revealed interclass differences significant at the .01 level. Cast-molded PMMA was the most laser-resistant IOL material.

Absent meibomian glands in the ectrodactyly, ectodermal dysplasia, cleft lip-palate syndrome.

A 27-year-old woman with the syndrome characterized by ectrodactyly, ectodermal dysplasia, and cleft lip-palate had an absent lacrimal punctum in each eye, with signs and symptoms of nasolacrimal obstruction during childhood. Examination disclosed bilateral corneal vascularization and opacification, with diffuse superficial punctate staining of the ocular surface epithelium by fluorescein, an instantaneous tear film break-up time, and normal Schirmer tear measurements. A full-thickness biopsy specimen of the eyelid confirmed the absence of meibomian glands that had been suspected because of absent meibomian gland orifices and secretions. The total absence of meibomian gland secretions in this patient may be a primary feature of this case and may contribute to a lipid-deficient and unstable tear film with resultant desiccation and destruction of the ocular surface epithelium. Breakdown of the corneal epithelium in association with obstruction and infection of the nasolacrimal system may be a particularly disastrous combination for the cornea that resulted in the recurrent, severe bacterial corneal ulcers found in our patient.

Mycobacterium fortuitum keratitis.

Two of four cases of Mycobacterium fortuitum keratitis occurred after corneal surgery with contact lens wear, one was associated with extended contact lens wear alone, and one occurred after a foreign body injury. All cases were characterized by pain, conjunctival hyperemia, stromal inflammation, and ulceration. Diagnosis was made by culture and acid-fast staining of corneal scrapings. On the basis of published experience with amikacin for the treatment of nonocular M. fortuitum infections, three patients were treated with topical amikacin. Two patients responded clinically, but histopathologic examination of a penetrating keratoplasty specimen in one of the two disclosed persistent infection. One patient was cured of early disease by debridement alone. Rapid diagnosis and absence of corticosteroid use were the two most important determinants of successful therapy. In advanced cases, infection may be cured and useful vision restored by penetrating keratoplasty.

Long-term results of Nd:YAG laser posterior capsulotomy with the Swiss laser.

The Microruptor II (MR-II) Nd:YAG laser developed by Fankhauser was evaluated in a national multicenter prospective study of posterior capsulotomy. Results are reported on 3,711 patients who underwent Nd:YAG laser photodiscission. Ninety-two percent of patients experienced an improvement in vision at some point following photodiscission and the postoperative complications of persistent cystoid macular edema and glaucoma occurred at rates of 2.5% and 0.2%, respectively, indicating the safety and efficacy of the MR-II for posterior capsulotomy.

Pathology and physics of YAG-laser intraocular lens damage.

Polymethylmethacrylate and silicone intraocular lenses were subjected to controlled Nd:YAG laser irradiation. Following damage, each lens was examined by scanning electron microscopy. Highly specific morphologic patterns, believed to be pathognomonic for each material, were observed. The physics of damage mechanisms and clinical correlation of damage morphology are discussed.

Comparison of glare in YAG-damaged intraocular lenses: injection-molded versus lathe-cut.

A comparative analysis of YAG laser intraocular lens (IOL) damage was undertaken on injection-molded and lathe-cut IOLs. Damage sites were evaluated with polarized light. A consistent positive polarization was observed in the damage sites of lathe-cut IOLs. A consistent negative polarization was observed in the damage sites of injection-molded IOLs. The presence of positive polarization in IOL damage sites may be correlated with increased potential for glare. Results and clinical implications are discussed.

Glare disability secondary to YAG laser intraocular lens damage.

Neodymium:YAG laser intraocular lens damage results in opacities in the pseudophakos. When located in the visual axis, these opacities may cause glare and image degradation. In this paper, we report a patient who experienced disabling glare sufficient to require the explanation of the YAG-damaged intraocular lens. The patient, her management and clinical course, and the pathology of the explanted lens are discussed.

Quantitative concepts in avoiding intraocular lens damage from the Nd:YAG laser in posterior capsulotomy.

Damage to the intraocular lens (IOL) in Nd:YAG laser posterior capsulotomy is a complication to be avoided. The damage threshold for many of the commercially available IOLs was determined. The power density at the focal point was calculated for FDA approved Nd:YAG lasers. Based on the therapeutic gap concept it is recommended that only power levels below the damage threshold be used in photodiscission posterior capsulotomy to minimize the risk of Nd:YAG laser IOL damage.

Posterior chamber intraocular lens implantation in ethnic minorities by resident housestaff.

The first 45 cases of extracapsular cataract extraction, with posterior chamber intraocular lens implantation performed by ophthalmology residents at an urban county hospital were evaluated. These cases, which were performed from March 1983 to June 1984, involved a patient population that was primarily black and Hispanic (88.8%). Over half the cases represent the first five cataract implant surgeries performed by five resident surgeons in their second and third year of residency. Twenty-eight of the 45 cases (62%) were available for examination six months postoperatively. Excluding two cases with decreased vision secondary to preexisting ocular disease, 100% of these patients achieved a best corrected visual acuity of 20/40 or better.

Wound healing following excimer laser radial keratotomy.

A pulsed excimer laser was used to produce radial keratotomy in vivo in human corneas and the wound healing process was studied. Fluences of 370 mJ/cm2 at a repetition rate of 20 Hz were effective and atraumatic. The wound healing process was remarkably uneventful without an inflammatory or immune reaction apparent at 21 days. Consistent flattening of the cornea was obtained by shallower cuts than with conventional radial keratotomy techniques.

Rationale for a program in community ophthalmology.

The high incidence of eye abnormalities among blacks, coupled with the relative unavailability of ophthalmic services, has resulted in excessive rates of blindness otherwise preventable or curable. As a consequence, incidence rates for blindness are higher for the black population than the white population.Statistics show that black children requiring eyeglasses are less likely to receive eyeglasses than similar age-matched white children. In virtually every state surveyed, blacks were more frequently and severely afflicted with eye diseases and were less likely to receive treatment than whites. Yet, no programs exist in any state specifically targeted to promote eye care among blacks and reverse the ever-worsening trend. Additional data characterizing the scope of the problem shall be presented.An initial strategy for approaching the problem, namely, community ophthalmology, has been developed. Community ophthalmology represents a new discipline promoting eye health and blindness prevention through programs utilizing methodologies of public health, community medicine, and ophthalmology. Basically, the use of community ophthalmology strategies is critical to positive out-come, when given a population composed of blacks and other minorities who are chronically underserved with regard to all sectors of health.The evolution and rationale for these concepts are discussed from national, as well as international, perspectives.

Lateral cantholysis and eyelid necrosis secondary to Pseudomonas aeruginosa.

A 16-month-old infant girl developed an acute lateral cantholysis and eyelid necrosis secondary to a severe Pseudomonas aeruginosa blepharitis and preseptal cellulitis. This uncommon complication of a pseudomonal external ocular infection occurred in the setting of malnutrition and failure-to-thrive. The lesion underwent satisfactory self-healing with the institution of antibiotic therapy and proper diet.

Removal of anterior chamber intraocular lenses: a surgical technique.

With the increasing trend toward intraocular lens implantation we are finding more cases in which explantation is indicated. The criteria and surgical techniques for explanation should be individualized depending on the type of lens. We describe removal of anterior chamber intraocular lenses.

Photometric evaluation of YAG-induced polymethylmethacrylate damage in a keratoprosthesis.

The use of the Nd:YAG laser in the photodiscission of retroprosthetic membranes represents a new clinical application. However, the potential adverse ophthalmic effects of YAG-induced PMMA damage to the keratoprosthesis are unknown. Consequently, precise photometric studies were conducted to evaluate image quality of the keratoprosthesis following YAG laser irradiation.