Dodick photolysis for cataract surgery: early experience with the Q-switched neodymium: YAG laser in 100 consecutive patients.

OBJECTIVE: To evaluate the safety and efficacy of a Q-switched neodymium:YAG (Nd:YAG) laser for removal of the human cataract. DESIGN: A multicenter, prospective, noncomparative study. PARTICIPANTS: A total of 100 consecutive eyes undergoing cataract extraction with the Dodick Photolysis, Q-switched Nd:YAG laser. MAIN OUTCOME MEASURE: Corneal endothelial cell loss, visual acuity improvement, intraocular pressure change, total intraocular energy used, and intraoperative and postoperative complications. RESULTS: The mean values were postoperative visual acuity improvement from 20/46.5 (0.43) to 20/26.6 (0.75), decrease in endothelial cell count of 177 cells/mm2 (7.55%), and intraocular energy used of 6.7 J. Minor complications were encountered in three cases. CONCLUSIONS: These data suggest that Dodick Photolysis may be a safe and effective new technology for cataract removal in human eyes. It appears to offer low intraocular energy and heat release, a clear-cornea incision less than 1.5 mm in size, and safe operation within the capsular bag.

Explantation of a foldable silicone intraocular lens.

PURPOSE: We used a novel technique for explanting an improperly oriented silicone intraocular lens. METHODS: The elastomeric property of silicone was used to deform the optic and remove the intraocular lens in one piece. RESULTS: We explanted a flexible intraocular lens without compromising the integrity of the original wound, posterior lens capsule, or corneal endothelium. CONCLUSIONS: The technique offers a superior means of intraocular lens explantation while retaining the benefits of small-incision cataract surgery.

Corneal complications of cataract surgery.

Recent advances in cataract surgery have reduced the incidence of corneal complications. Review of the current literature reveals a trend toward early visual rehabilitation and minimization of postoperative astigmatism by careful selection of incision type and location for small-incision cataract surgery. Since the introduction of intraocular lenses, endothelial cell loss has been a concern. Preservation of corneal endothelial cell function continues to be a major goal as cataract surgery continues to evolve. Recent studies have been undertaken to determine the effect of incision location and size on endothelial cell loss. Several reports on iatrogenically induced corneal decompensation are of interest as this complication can be avoided if proper precautions are taken. Although improvements in surgical technique have lead to a decreased incidence of Descemet's membrane detachments and of epithelial and fibrous downgrowth, early recognition and intervention are imperative.

Laser therapy in cataract surgery.

In the more than 25 years since the development of ultrasound phacoemulsification, enormous change has occurred in cataract surgery. One of the latest and most significant changes in cataract surgery has been the development of devices that utilize laser energy for the removal of cataracts. Both ultraviolet (excimer) and infrared wavelengths have been studied, but in 1994, we have seen significant progress only with the infrared wavelengths. The lack of progress in the devices utilizing ultraviolet wavelengths are due to concerns with safety. Two infrared laser devices, one developed by Dodick and the other developed by Colvard have been used successfully for the removal of cataracts under Investigational Device Exemptions from the Food and Drug Administration. These developments have brought us a step closer to realizing the dream of laser cataract surgery.

Laser therapy in cataract surgery.

Since the development of ultrasound phacoemulsification more than 25 years ago, cataract surgery has changed dramatically. One of the major changes in cataract surgery has been the research into the use of laser for the removal of cataracts. To date, both ultraviolet and infrared wavelengths have been studied, with the infrared showing more promise. The ultraviolet end of the spectrum has shown promise, but concerns with safety have hindered its progress. An infrared laser device developed by Dodick has been used successfully for the removal of cataracts under an Investigational Device Exemption from the Food and Drug Administration and a second infrared laser developed by Colvard should be approved soon. These developments have brought us a step closer to realizing the dream of laser cataract surgery.

Pigmentation and inhibition of wound contraction by cultured skin substitutes with adult melanocytes after transplantation to athymic mice.

Wound closure with cultured skin substitutes results in epithelium that is consistently hypopigmented. Hypothetically, addition of human melanocytes to cultured skin grafts may result in normal pigmentation of healed skin. Skin substitutes were composed of human epidermal keratinocytes and melanocytes, dermal fibroblasts, and collagen-glycosaminoglycan substrates, and were incubated for 12 d in media for keratinocyte growth (KG, n = 4), for keratinocyte differentiation containing four fatty acids and vitamin E with basic fibroblast growth factor (KDF, n = 6) or epidermal growth factor (KDE, n = 6), or for melanocyte growth (MG, n = 6) with phorbol ester and 5% fetal bovine serum. Skin substitutes were grafted orthotopically to full-thickness skin wounds (2 x 2 cm) on athymic mice, and scored for percent original wound size (+/- SEM), visible pigmentation (number pigmented/n), and positive staining for human leukocyte antigens (HLA)-ABC after 6 weeks on the mice. The data show that cultured skin grafts containing human melanocytes that are incubated in KDE or MG media have statistically significant reduction in wound contraction, 1:1 correlation of expression of pigment and HLA-ABC, and increased frequency of pigmentation after healing compared to incubation in KG or KDF media. Transmission electron microscopy confirmed the presence of melanocytes, melanosomes, and pigment transfer to keratinocytes in pigmented skin. These results suggest that survival and differentiated function of cultured epithelium can support melanization of skin, and that skin analogues exposed to phorbol ester in vitro can support skin pigmentation after wound healing.

Lasers in cataract surgery.

Several laser technologies including 1053-nm picosecond, excimer, erbium:yttrium-aluminum-garnet, and neodymium:yttrium-aluminum-garnet (Nd:YAG) have been studied for use in the removal of cataractous lens tissue. Nd:YAG laser phacolysis involves laser pulses striking a titanium target that are incorporated into an irrigation-aspiration probe. With further refinement, Nd:YAG laser phacolysis may provide an alternative means of lens removal through a small incision, however, further study is required.

Experimental studies on the development and propagation of shock waves created by the interaction of short Nd:YAG laser pulses with a titanium target. Possible implications for Nd:YAG laser phacolysis of the cataractous human lens.

The formation and propagation of shock waves created by the interaction of high powered Nd:YAG laser pulses with a titanium target are photographed and analyzed. The titanium target is located at the distal end of a probe, similar to an irrigation/aspiration probe used in cataract surgery, and the Nd:YAG laser is delivered by a cladded 300 microns quartz fiber. This device, and the results of this study, are being applied to develop a device for fragmenting nuclear material for cataract extraction.

Bilateral and extensive xanthelasma palpebrarum in a young man.

A 25-year-old white man had been aware since childhood of yellow discolorations of the medial aspects of his upper lids. The skin changes progressively spread to involve all four eyelids, the inferior skin of the brow, and the lateral and medial canthal skin. The clinical diagnosis was extensive bilateral xanthelasmas . The patient had no manifest abnormality of lipid metabolism, although his father and grandfather had both developed xanthelasmas early in childhood. A snip biopsy of upper lid skin was performed and studied by both light and electron microscopy. The light microscopic appearance confirmed the diagnosis of xanthelasma, in that the upper dermis contained mono- and multinucleated foamy xanthoma cells beset with myriad cytoplasmic vacuoles. Cells displaced outwardly into the interstitium evidenced degradation phenomena within the vacuoles, consisting of lamellar bodies or fingerprint-like inclusions, presumably the result of fusion of lysosomes with the lipidic inclusions. Scattered non- lipidized mononuclear histiocytes with abundant profiles of smooth-surfaced endoplasmic reticulum possibly represented a reserve population of monocytes for conversion into xanthoma cells.

Initial clinical results with YAG laser capsulectomy with a monomode, Q-switched unit (LASAG).

We present initial clinical experience for posterior capsulectomy with a monomode, Q-switched YAG laser (LASAG). Results indicate 100% capsulectomy success with less than 100% visual improvement. Complications were minimal and usually transient. Implant nicking was reduced by using low energy levels and precise focusing, and by the surgeon's increased facility with experience.