Anesthesia for intraocular surgery.

Surgeons must decide on the type of anesthesia to use when performing cataract surgery. These "viewpoints" articles provide a well-balanced discussion offering the pros and cons of both topical anesthesia and retrobulbar/peribulbar injection. Dr. Dutton gives an overview of both techniques, focusing on relevant orbital anatomy. Drs. Hassan, Edelhauser and Kim, review the various types of topical anesthesia currently in use, and Drs. Spriggs and Broocker examine retrobulbar and peribulbar injections. Both techniques are associated with advantages and risks, so each surgeon must decide which technique is best suited for his or her own practice.

The effect of relative spectacle magnification on aniseikonia.

PURPOSE: The purpose of this article is to study the effects of modifying relative spectacle magnification to determine what effect this has on aniseikonia, binocularity, and visual comfort. METHODS: A prospective analysis of 34 aniseikonic patients was undertaken. The etiology of aniseikonia varied from physiologically occurring to induced. Aniseikonic screening included manifest refraction, keratometry, axial length, Randot stereoacuity, associated phoria, and Keystone space eikonometry. A modified pair of spectacles was fabricated on the basis of magnification principles for iseikonic lenses. Each patient was also given a control pair of conventional spectacles. A 4-week trial period was allowed for each pair of spectacles, pertinent examination measurements were repeated, and a patient survey was administered. Data were analyzed by t-test and chi-square. RESULTS: Modifying relative spectacle magnification reduced mean aniseikonic error by 1.06% (P < 0.0001). A difference was found between the control and modified spectacles for subjective reports of visual comfort, performance, and eye-strain (P < 0.05). There was no difference between the two groups for stereoacuity or cosmetic appearance of lenses. At the conclusion of the study, 93% of patients preferred the modified lenses in direct comparison. CONCLUSIONS: Our results confirm that modification of lens designs to equalize relative spectacle magnification reduces aniseikonia and improves subjective comfort and performance of anisometropic spectacles.

The effects of intraocular lidocaine on the corneal endothelium.

OBJECTIVE: The study aimed to evaluate the direct effect of intraocular lidocaine hydrochloride (HCl) 1% on corneal endothelial cell function, ultrastructure, and viability using an in vitro perfusion specular microscope system. DESIGN: Paired rabbit and human corneas were isolated and mounted in an in vitro specular microscope for endothelial perfusion evaluation. Corneas were perfused with a control solution (BSS Plus for humans, glutathione bicarbonate Ringer's [GBR] for rabbits) for a 1-hour stabilization period. After the stabilization period, one cornea of each matched pair was perfused with preservative-free lidocaine HCl 1% for 15 minutes followed by control solution for an additional 2 to 3 hours. The control cornea continued to receive either GBR or BSS Plus. Corneal thickness measurements were taken every 15 minutes throughout the perfusion period. Corneal swelling and deswelling rates were calculated by linear regression analysis. At the end of the experiment, corneas were fixed for scanning and transmission electron microscopy. In another group of corneas, the endothelial viability was assayed after direct perfusion with lidocaine HCl 1%. RESULTS: Lidocaine HCl 1% caused endothelial cell edema, which reversed on removal of lidocaine from perfusion media. Corneal swelling and deswelling rates did not differ significantly between the lidocaine and control groups. Electron microscopy showed the effects of transient endothelial cell edema with an otherwise normal mosaic pattern and ultrastructure for both treatment groups. Endothelial cell viability was maintained after the direct lidocaine exposure and a 2-hour washout. CONCLUSIONS: Lidocaine HCl 1% causes a transient endothelial cell edema to the in vitro perfused endothelium of human and rabbit corneas. Proper attention should be given to the type of lidocaine injected intraocularly (i.e., concentration, vehicle, preservatives, pH, osmolarity). Although lidocaine HCl 1% appears to be safe to both human and rabbit endothelium during short-term in vitro exposure, further in vivo and in vitro studies are needed to determine long-term effects of intraocular lidocaine on the corneal endothelium.

Contemporary management of aniseikonia.

The diagnosis and management of aniseikonia has become a lost art. Refractive surgery and intraocular lens implantation has created a new patient population of anisometropia. Measurement of aniseikonia through instrumentation such as the space eikonometer is not readily available. Therefore, estimating the degree of aniseikonia based on the dioptral differences between the two eyes may be the most practical approach. The optical principles of spectacle magnification can be translated by the prescribing eye doctor to reduce ocular image disparity. Contemporary lens designs, such as hi-index and aspherics, allow the practitioner to modify shape and power factors to achieve higher levels of aniseikonic correction in a cosmetically fashionable pair of spectacles.

The use of sodium hyaluronate (Healon) in intracapsular cataract extraction with insertion of anterior chamber intraocular lenses.

Intracapsular cataract extraction with insertion of anterior chamber intraocular lens was carried out on 40 subjects. In 21 procedures, balanced salt solution or air was used to deepen the anterior chamber. In 19 procedures, Hyaluronic Acid (Healon) was used to deepen the anterior chamber. In the two groups, no significant difference was noted in the endothelial cell count or in the corneal thickness. The surgeon felt that Healon made the surgery much easier, gave better control and greatly decreased the possibility of serious complications.

Choroidal osteoma in a 6-year-old child.

A healthy 6-year-old black girl presented with an asymptomatic lesion in the posterior pole of the left eye. The lesion had the classic clinical features on ophthalmoscopy and ultrasonography of a choroidal osteoma. It is important that other benign and malignant processes such as malignant melanoma, metastatic tumor, and choroidal hemangioma can simulate this benign tumor. A good clinical history and examination followed by carefully selected ancillary tests such as ultrasonography should confirm the diagnosis of choroidal osteoma. To our knowledge this case is the youngest reported case and the first black patient reported.