Astigmatic stabilization of 3.0 mm temporal clear corneal cataract incisions.

PURPOSE: To determine the time needed for corneal shape changes to stabilize after a laterally oriented, 3.0 mm, unsutured, single-hinge clear corneal tunnel cataract incision combined with implantation of a foldable acrylic 5.5 mm intraocular lens. SETTING: Advanced Vision Care, West Hills, California. METHODS: The study comprised 45 patients who had a similar phacoemulsification technique and lens implantation through an unenlarged 3.0 x 2.5 mm self-sealing temporal clear corneal tunnel incision. Changes in corneal curvature were determined by computerized videokeratography (corneal topography) prior to surgery and at 1, 2, and 6 weeks after surgery. Simulated keratometry was ascertained from topography and analyzed with the Lens-Stat software program. RESULTS: Preoperative corneal cylinder, cylinder axis, and central corneal curvature did not change markedly after surgery. By vector analysis, approximately 0.50 diopter (D) of induced cylinder was noted, whereas less than 0.25 D of cylinder change was observed in the surgical meridian. Although statistically similar, there were slight differences between the data at 1 and 2 weeks postoperatively. However, the 2 and 6 week data were indistinguishable, indicating that the incision method used in the study was fully stable within 2 weeks of surgery. CONCLUSIONS: The surgical method resulted in stable corneal curvature by 2 weeks after surgery at which time the patient is ready for final spectacle prescription and can be discharged from acute postoperative ophthalmologic care in the absence of complicating factors. The shortened recovery time is beneficial for the patient and has significant potential effects on the global costs of cataract rehabilitation and the reimbursement schemes for postoperative management.

Short-and long-term effect of clear corneal incisions on intraocular pressure.

PURPOSE: To evaluate short- and long-term intraocular pressure (IOP) after cataract surgery using clear corneal incision to assess whether there is a statistically significant postoperative IOP decrease. SETTING: Advanced Vision Care, West Hills, California. METHODS: We retrospectively 135 eyes of 89 randomly selected patients who had scleral tunnel or clear corneal cataract surgery with a follow-up of at least 6 months. Patients with pre-existing glaucoma were excluded. RESULTS: In the clear corneal group (n = 84), mean IOP was statistically significantly lower (P = .019) 12 months after surgery than preoperatively (13.65 versus 15.57 mm Hg). Although there was a trend toward decreased IOP in the scleral tunnel incision group (n = 51), the difference was not statistically significant (P = .178). CONCLUSION: We found a trend toward lower IOP that, if permanent, raises serious implications about the necessity of combined procedures in patients with both glaucoma and cataract.

Neodymium:YAG laser optical opening for retained Descemet's membrane after penetrating keratoplasty.

A 78-year-old woman who had intracapsular cataract extraction and anterior chamber intraocular lens implantation 8 years earlier presented with decreased visual acuity (20/400) and discomfort of 2 years duration in the operated eye. Penetrating keratoplasty was done to improve visual function and reduce discomfort; however, at 6 months postoperative, visual acuity was 20/800, due in part to retained opacified host corneal tissue. A retrograft (duplicate) membrane was identified at the posterior aspect of the graft/host junction. The neodymium:YAG laser was used to create a central 3.5 mm circular opening in the duplicate membrane. There were no complications from the laser treatment. The donor cornea remained thin and clear, and visual acuity improved to 20/40 with spectacle correction. It is imperative to confirm complete removal of host corneal tissue before implanting donor tissue; however, vision can be restored, and a corneal graft can remain clear following laser membranotomy.

Small-diameter corneal inlay in presbyopic or pseudophakic patients.

We report the results of using the small-diameter corneal inlay to create a bifocal cornea. The inlay was implanted in five eyes in January 1993. At 12 months postoperatively, uncorrected near vision had improved from J4 to better than J2 in four of the five. The results indicate that the corneal inlay improves near vision and is compatible within the cornea.

Comparison of three keratometry instruments.

We compared the reliability of measurements of three keratometers and keratometry readings from a corneal topography system to determine if they were as accurate as the "gold standard" Javal-Schiotz keratometer. Same-day measurement of the steepest and flattest powers of the central 3 mm of the corneas of 200 eyes (100 patients) revealed no statistically significant difference in reliability between the newer keratometers and the Javal-Schiotz. In addition, the newer machines are more convenient and efficient in some clinical settings.

The use of collagen shields for drug delivery in cataract and intraocular lens surgery.

Collagen shields are an appealing route of drug administration because they avoid complications associated with periocular injections and frequent topical drug application. A review of past studies establishes the capability of collagen shields to reach therapeutic aqueous drug levels in animal models. More recent studies on human subjects reaffirm the capability of collagen shields to provide adequate prophylaxis against the most common pathogens of postoperative endophthalmitis. Research on the use of collagen shields after routine cataract surgery shows that patients receiving the collagen shields had less postoperative anterior chamber reaction, less corneal edema, and fewer subconjunctival hemorrhages when compared with patients receiving the same medication through subconjunctival injection. Collagen shields may also be useful as a means to deliver other medications such as antivirals, antifungals, and immunosuppressive agents.

Leukocytes from four patients with complete or partial Leu-CAM deficiency contain the common beta-subunit precursor and beta-subunit messenger RNA.

Deficiency of a family of three leukocyte adhesion molecules (Leu-CAM) is associated with recurrent and life-threatening bacterial infections in man. Each of the three antigens, Mo1, LFA-1, and Leu M5 has a distinct alpha subunit noncovalently associated with a common beta subunit that appears to be required for the expression of these antigens on the cell surface. To investigate the molecular basis of Leu-CAM deficiency, we studied leukocytes from four unrelated patients suffering from complete or partial Leu-CAM deficiency using immunoprecipitation of metabolically labeled proteins, RNA extraction, and Northern blot analysis. We found that B cells from all four patients synthesized a normal sized beta subunit precursor that either failed to "mature" or matured only partially to the membrane expressed form. B cells from all four patients also had a single normal sized beta subunit mRNA of approximately 3.4 kb. Leu-CAM deficiency, in these unrelated patients, is not due to the absence of the beta chain gene or to aberrant splicing of its mRNA and are consistent with a defective beta subunit gene resulting in abnormal posttranslational processing of the synthesized molecule.