Perception of Purkinje vessel shadows and foveal granular pattern as a measure of potential visual acuity.

PURPOSE: To compare perception of 2 entoptic phenomena, the Purkinje vessel shadows and the foveal granular pattern, as measures of retinal visual acuity using a transscleral illumination technique that bypasses the anterior segment. SETTING: Retinal Vascular Center and General Eye Clinic, Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, USA. METHODS: Both eyes of 85 patients with clear ocular media, many with retinal disease, were tested for perception of these entoptic phenomena. Also, retinal visual acuity was measured with a Potential Acuity Meter through the current refractive correction. RESULTS: Of 114 eyes with retinal acuity of 20/40 or better, 99% perceived the Purkinje vessel shadows and 86% perceived the foveal granular pattern. Of 45 eyes with retinal acuity of 20/80 or worse, 73% perceived the Purkinje vessel shadows and 4% perceived the foveal granular pattern. CONCLUSION: Perception of the Purkinje vessel shadows does not distinguish between good and poor retinal acuity, whereas nonperception of the vessel shadows strongly suggests poor acuity. Perception of the foveal granular pattern, on the other hand, provides a positive indication of good retinal acuity and will likely prove to be predictive of good vision after removal of significant media opacity.

Worldwide legal requirements for obtaining corneas: 1990.

Cornea transplantation offers the hope of restoring useful vision to millions of individuals worldwide. Yet it is widely used only in certain countries. While a lack of the necessary economic and technical infrastructure is the primary reason in many countries, the legal and social systems pose a similar obstacle in many other more prosperous countries. This article reviews the current laws governing organ and tissue donation throughout the world and distinguishes those that are most successful in obtaining tissue for transplantation.

Changing indications for cataract surgery: 1974 to 1988.

To examine changes in indications for cataract surgery which have contributed to the increasing rate of cataract extractions, we compared preoperative characteristics of 265 patients who had undergone surgery in 1988 with a similar number who had undergone surgery by the same four ophthalmologists in 1974 and 1982. Between 1974 and 1988 the number of extractions performed annually by two high-referral hospital-based surgeons rose by 68%. Over 90% of these procedures in 1974 were intracapsular extractions; in 1988, 90% were extracapsular extractions with intraocular lenses. In 1988, preoperative visual acuity was better in both the study eyes and the fellow eyes, the proportion of those with acuities better than 20/60 having risen from 10% to 21%, and from 49% to 67%, respectively. The proportion of patients waiting more than 2 years for surgery on the second eye doubled between 1974 and 1988. These changes, already evident by 1982 for the hospital-based surgeons, became characteristic of the community-based surgeons' practices as well between 1982 and 1988.

Visual disabilities related to intraocular lens design.

Intraocular lens implantation after cataract extraction has become a common practice in the United States. However, unwanted optical images can correct an otherwise successful surgery into one that causes patient dissatisfaction. Refinements in manufacturing design and finishing have greatly improved the quality of present day intraocular lenses, but there is continued interest in simulating the optics of the human crystalline lens. We will discuss the optical requirements of intraocular lenses and how these are influenced by optic design and dimension, and spectral transmission characteristics.

Idiopathic presenile cataract formation and galactosaemia.

Five hundred patients undergoing cataract surgery were prospectively examined, and 46 Caucasian patients were found to have strictly idiopathic cataracts severe enough to warrant surgery on or before age 55. In a masked fashion we determined the activity of galactokinase (GK) and galactose-1-phosphate uridyl transferase (GPUT) in these patients as well as on 53 age matched controls. With respect to GK no cataract patient had an enzyme level of less than 2 standard deviations below the control mean. However, 3 of 45 (6.7%) patients in the cataract group had a GPUT level less than 2 standard deviations below the mean for controls, and were presumably heterozygotes for this enzyme. In comparison with the expected population rate of 0.8% this is highly significant (p = 0.006). Abnormalities in galactose pathway enzymes may therefore predispose to development of presenile cataracts. In affected people there is a possibility of treating these patients clinically by dietary restriction of dairy products or by using aldose reductase inhibitors to prevent or reverse cataract formation.

The efficacy and safety of combined trabeculectomy, cataract extraction, and intraocular lens implantation.

The safety and efficacy of combined trabeculectomy, extracapsular cataract extraction (ECCE), and posterior chamber intraocular lens (PC IOL) implantation were evaluated by retrospectively analyzing 108 consecutive operations. Postoperatively, 89% of eyes achieved 20/40 or better visual acuity when preoperative macular and optic nerve diseases were excluded. Mean follow-up was 16.8 months. Intraocular pressure (IOP) control (less than or equal to 21 mmHg) was achieved in 92% of eyes; 57% required no medications. Capsulotomy (20%) and transient hyphema (15%) occurred significantly more often (P less than 0.001) than in a comparison group. These results suggest that the combined procedure gives excellent visual rehabilitation and IOP control in the majority of patients included in this analysis.

Cataract extraction after retinal detachment surgery.

Extracapsular cataract extraction (ECCE) was done in 31 eyes of 27 patients after previous retinal reattachment surgery with scleral buckling. A posterior chamber intraocular lens (IOL) was implanted in 21 eyes. No significant modifications in the cataract surgical technique were necessary. Final visual acuity was 20/40 or better in 26 eyes (84%). The complication rate was low. One patient was found to have a retinal detachment (RD) after cataract extraction that probably predated the cataract surgery. No recurrent retinal tears or detachment developed in any patients during an average 24-month follow-up period.

Continuing corneal endothelial loss in intracapsular surgery with and without Binkhorst four-loop lenses: a long-term specular microscopy study.

We analyzed pre- and postoperative corneal endothelial photographs of 17 intracapsular cataract extractions (ICCE) with Binkhorst four-loop intraocular lens (IOL) eyes and found 11.6% mean cell loss at 2 months (previously reported by Hirst et al) increasing to 42.4% after 5 years (p less than 0.05) and 51.8% at 7 years. Eleven ICCE eyes without IOLs similarly examined showed a 15.6% mean cell loss at 2 months (previously reported by Hirst et al), increasing to 33.4% at 5 years (p less than 0.005, paired t-test). Our results appear to indicate long-term continuing cell loss after ICCE, both with and without Binkhorst four-loop iris clip IOLs, and statistically significant greater cell loss (p less than .001, unpaired t-test) with IOLs than without.

Drg-39.

The development of extracapsular cataract extraction with insertion of an intraocular lens has undoubtedly been one of medical science's greatest advances in the rehabilitation of vision. It has also lead to vigorous debates within and without the profession about the efficacy of the procedure and its cost-benefit ratio. Criticism directed toward cataract surgery, both by those in the medical profession and those in governmental agencies, must be addressed if ophthalmologists are going to continue to be able to meet the needs of their patients.

Treatment of Mooren's and Mooren's-like ulcer by lamellar keratectomy: report of six eyes and literature review.

Three cases of Mooren's ulcer (four eyes) and one case of marginal corneal ulcer associated with relapsing polychondritis (two eyes) are presented with decrease in ocular inflammation following extensive lamellar keratectomy or lamellar keratoplasty. Tissue adhesive was needed in two cases to maintain ocular integrity. The procedure may work by the removal of a corneal antigenic stimulus to a self-perpetrating auto-immune phenomenon that causes corneal melting. More cases are needed to evaluate the therapeutic efficacy of lamellar keratectomy for Mooren's and Mooren's-like corneal ulcers.

Cataract extraction after vitrectomy.

Cataract extractions were performed in 25 patients who had previously undergone pars plana vitrectomy. Posterior chamber IOLs were implanted in 20 of 26 eyes. Modification of the usual surgical technique was often necessary because the zonules and/or posterior capsule were unusually mobile. Lens opacities were nuclear sclerotic in 17 eyes (65%) and posterior subcapsular in nine eyes (35%). Visual acuity improved an average of five lines, and final visual acuity was 20/50 or better in 13 eyes (50%). Visual acuity after cataract extraction closely paralleled the best visual acuity after vitreous surgery in all patients. Complications were tears in the posterior capsule in two eyes and postoperative vitreous hemorrhage in one eye. These complications did not limit final vision.

Retinal detachment after extracapsular cataract extraction with posterior chamber intraocular lens.

The authors reviewed 3065 consecutive cases of extracapsular cataract extraction with posterior chamber lens implant (ECCE-PC IOL) and found the incidence of retinal detachment to be 1.4% overall (44/3065) and 1.7% in a group of eyes followed for at least 1 year (40/2330). Retrospective analysis of the retinal detachment (RD) group (n = 44) showed the patients to be significantly younger than the overall group (n = 3065) (P less than 0.0001). Comparison with an age-matched group of 302 eyes without RD showed higher rates of RD in males (P = 0.0013) and in eyes with axial eye length (AEL) greater than 25 mm (P less than 0.0001). No significant correlation was found between RD and PC IOL manufacturer, phacoemulsification (PKE), or primary discission. Sixty-four percent of RDs occurred within 1 year of cataract operation. Only 10% occurred more than 2 years later. Visual results in eyes with ultimate anatomic success of RD repair (43 of 44 eyes, averaging 15 months follow-up) are substantially better than previously reported in series with other types of IOLs (96% greater than or equal to 20/40 if the macula was not involved, 75% greater than or equal to 20/40 if the macula was involved).

Current concepts in intraocular lens implantation.

PC IOLs appear to be safe and effective and there are few contraindications. Based on the available data we feel confident about implanting PC IOLs in healthy eyes of patients aged 40 or older. For younger patients, we do not recommended an IOL unless glasses or contact lens use is not feasible. Caution is urged however in the use of semiflexible, closed-loop AC IOLs as well as 'soft' PC IOLs. Other questions regarding material of choice, bag versus sulcus fixation, and UV absorbers remain controversial.