Richard S. Ruiz

A three-part system for refining intraocular lens power calculations

ABSTRACT A three‐part system that determines the correct power for an intraocular lens (IOL) to achieve a desired postoperative refraction is presented. The three components are (1) data screening criteria to identify improbable axial length and keratometry measurements, (2) a new IOL calculation formula that exceeds the current accuracy of other formulas for short, medium, and long eyes, and (3) a personalized “surgeon factor” that adjusts for any consistent bias in the surgeons results, from any source, based on a reverse solution of the new formula; the reverse solution uses the postoperative stabilized refraction, the dioptric power of the implanted IOL, and the preoperative corneal and axial length measurements to calculate the personalized surgeon factor. The improved accuracy of the new formula was proven by performing IOL power calculations on 2,000 eyes from 12 surgeons and comparing the results to seven other currently used formulas.

A Randomized Double-Masked Trial Comparing Ketorolac Tromethamine 0.5%, Diclofenac Sodium 0.1%, and Prednisolone Acetate 1% in Reducing Post-Phacoemulsification Flare and Cells

BACKGROUND AND OBJECTIVEnTo compare the efficacy of ketorolac tromethamine 0.5%, diclofenac sodium 0.1%, and prednisolone acetate 1% in reducing flare and cells following cataract surgery.nnnPATIENTS AND METHODSnFifty-eight patients undergoing phacoemulsification with posterior chamber intraocular lens implantation were randomly selected to receive either ketorolac tromethamine 0.5%, diclofenac sodium 0.1%, or prednisolone acetate 1% following surgery. The treatment regimen was 1 drop 4 times a day for 1 week, then twice a day for the next 3 weeks. Flare, cells, and intraocular pressures (IOPs) were measured preoperatively and on postoperative days 1, 7, and 28.nnnRESULTSnNo statistically significant differences in either actual flare or cell counts or in change in flare or cell counts from baseline were detected among the three groups. No statistically significant differences in IOP or in change of IOP from preoperative measurements were detected. No medication-related complications were noted at any time.nnnCONCLUSIONnKetorolac tromethamine 0.5% and diclofenac sodium 0.1% may be as effective and as safe as prednisolone acetate 1% in controlling inflammation following cataract extraction.

Visual outcome in pseudophakic eyes with clinical cystoid macular edema

Thirty-nine eyes with clinical cystoid macular edema (CME) following extracapsular cataract extraction and intraocular lens (IOL) implantation were reviewed retrospectively. Chronic CME, defined as clinically symptomatic CME persisting more than 6 months, developed in 14 of the 39 eyes (36%): in 5 of the 7 (71%) eyes in which vitreous loss occurred and anterior chamber IOLs were implanted; and in 9 of 32 (28%) eyes in which no complications occurred and posterior chamber IOLs were implanted. The mean duration between diagnosis and last follow-up visit was 34 months. Only 4 of the 14 eyes (29%) with chronic CME achieved a visual acuity better than 20/40. Vitreous loss did not affect long-term visual prognosis.

Posterior Chamber Intraocular Lens Implantation in Eyes With Inactive and Active Proliferative Diabetic Retinopathy

We reviewed the records of 2,100 consecutive eyes that had undergone extracapsular cataract extraction with intraocular lens implantation between January 1981 and December 1989. Of these eyes, 21 had inactive and four had active proliferative diabetic retinopathy at the time of cataract extraction. Twenty-one eyes with inactive proliferative diabetic retinopathy received extracapsular cataract extraction with posterior chamber intraocular lens implantation, and four eyes with active proliferative diabetic retinopathy had both extracapsular cataract extraction with posterior chamber intraocular lens implantation and pars plana vitrectomy with endophotocoagulation. The mean follow-up period was 27 months. Final visual acuity was 20/40 or better in 12 of 25 eyes (48%). Of 25 eyes, five (20%) showed progression of the retinopathy after the operation, and two (8%) developed macular edema. Extracapsular cataract extraction and posterior chamber intraocular lens implantation was well tolerated in most eyes.

Reproducibility of the Laser Flare Meter and Laser Cell Counter in Assessing Anterior Chamber Inflammation Following Cataract Surgery

BACKGROUND AND OBJECTIVESnTo determine the interobserver and intraobserver reproducibility of the laser flare meter and laser cell counter in assessing anterior chamber inflammation following cataract surgery.nnnPATIENTS AND METHODSnThirty-nine eyes with varied degrees of inflammation and 9 normal eyes were included in the study. Anterior chamber flare and cells were evaluated with the slit lamp and graded on a scale of 0 to 4+. The flare and cells were then measured three times each using the flare meter and cell counter by two different, experienced observers. The intraobserver reproducibilities were computed to evaluate repeatability of the instruments operated by the same observer. The first measurement taken by each observer was used to assess reproducibility between the two observers.nnnRESULTSnThe intraobserver reproducibility for overall flare was 0.995 for both observers. The intraobserver reproducibility for overall cells was 0.996 for observer 1 and 0.991 for observer 2. The overall interobserver reproducibility was 0.994 for flare and 0.988 for cells. The correlation between measurements and slit-lamp ratings was 0.78 for flare and 0.56 for cells.nnnCONCLUSIONSnThe intraobserver and interobserver reproducibilities were excellent, with good correlation to slit-lamp measurements. Reproducible results can be obtained using the laser flare meter and the laser cell counter. It is not known whether these results are applicable to other inflammatory processes with higher grades of flare and cells and with different protein and cell types.

Lyme disease associated with unilateral interstitial keratitis

PURPOSEnTo report a case of Lyme disease that presented with a single nummular unilateral interstitial keratitis.nnnMETHODSnCase report and review of the literature.nnnRESULTSnA 57-year-old black man who had contact with freshly killed deer had a chief complaint of foreign-body sensation in his right eye (OD) that had been diagnosed and treated for herpes simplex stromal keratitis. The patient underwent a systemic workup for interstitial keratitis. All results including RPR and MHA-TP were negative except for Lyme antibody titer (enzyme-linked immunosorbent assay [ELISA]) 178 U/ml (normal, <159 U/ml).nnnCONCLUSIONnInterstitial keratitis from Lyme disease has been regarded as a bilateral disease in the literature. We present this infrequent ocular manifestation of Lyme disease as a rare single nummular unilateral presentation.

Extracapsular Cataract Extraction With Intraocular Lens Implantation After Scleral Buckling Surgery

We reviewed the records of 28 patients who had undergone successful scleral buckling surgery followed by extracapsular cataract extraction with implantation of an intraocular lens. Posterior chamber intraocular lenses were inserted in 27 eyes, and anterior chamber intraocular lenses were inserted in two eyes with posterior capsule rupture at the time of surgery. The mean follow-up period was 44 months. Final visual acuity was 20/40 or better in 15 of 29 eyes (52%). One eye (3.4%) developed a recurrent retinal detachment 15 months after cataract surgery. Two eyes (6.9%) developed angiographically proven cystoid macular edema. The outcome for extracapsular cataract extraction with intraocular lens implantation in eyes that had previously undergone successful scleral buckling for retinal detachment is favorable.

Consensual inflammation following ocular surgery.

PURPOSEnTo determine whether a consensual inflammatory response occurs following unilateral phacoemulsification or trabeculectomy in humans.nnnMETHODSnSixty patients undergoing phacoemulsification or primary trabeculectomy were included in the study. Some patients were randomly assigned to have a shield placed on the non-operated eye during surgery. The Kowa laser flare meter (FM-500) and laser cell counter (LC-500) (Kowa Electronics and Optics, Tokyo, Japan) were used to assess the inflammatory response in both eyes. Measurements were taken preoperatively and on postoperative days 1, 7 and 28. The regression analysis with random model effect was used to identify factors which may affect the change of flare and cells in the non-operated eye after surgery. Correlation was evaluated between the inflammatory responses of the paired eyes. A P<0.05 was considered statistically significant for all analyses.nnnRESULTSnThe flare and cells in the non-operated eye showed a small, but significant, increase on day 1 (mean flare increased 2.68 photons/ms from preoperative level with P<0.001 and mean cells increased 2.49 cells/0.5 mm3 from preoperative level with P<0.0001). At day 7 the amount of inflammation was still elevated (mean flare increased 0.41 photons/ms from preoperative level with P<0.001 and mean cells increased 0.63 cells/0.5 mm3 from preoperative level with P<0.001). By day 28, the amount of inflammation in the nonoperated eyes returned to preoperative levels.nnnCONCLUSIONSnSubclinical inflammation occurs in the non-operated eye following phacoemulsification and trabeculectomy. The etiology of this finding has yet to be elucidated.

Intraocular pressure during enflurane and neurolept anesthesia in adult patients undergoing ophthalmic surgery

The effects of neurolept and enflurane anesthesia on intraocular pressure (IOP) were studied in 20 patients undergoing elective ophthalmic surgery. Ten received neurolept and ten enflurane anesthesia. Continuous EEG tracings recorded the level of anesthesia. IOP was measured before and at intervals during anesthesia at varying concentrations of enflurane and incremental doses of fentanyl.During level I neurolept anesthesia IOP increased from control values of 18.10 ± 0.93 mm Hg (mean ± SEM) to 19.50 ± 1.65 mm Hg, but decreased to 14.55 ± 0.84 mm Hg during level II and to 12.29 ± 1.13 mm Hg during level III anesthesia. During enflurane anesthesia IOP decreased from control values of 19.00 ± 1.44 mm Hg (mean ± SEM) to 14.50 ± 1.60 mm Hg during level I, 14.10 ± 1.04 mm Hg during level II, and 11.60 ± 1.46 mm Hg during level III anesthesia. The increase in IOP during neurolept level I anesthesia was not statistically significant but the decreases in IOP from control values during levels II and III anesthesia were statistically significant. Decreases in IOP from control values were statistically significant at all levels of enflurane anesthesia. There was, however, no statistical significance between the differences in IOP values during levels II and III neurolept anesthesia, nor between levels I, II, and III enflurane anesthesia. The differences in the mean IOP values between neurolept and enflurane anesthesia were statistically significant only during EEG level I anesthesia.

Alfentanil decreases the excitatory phenomena of sodium methohexital

STUDY OBJECTIVEnTo evaluate the effects of alfentanil or lidocaine on the excitatory phenomena (myoclonus, cough, hiccough) caused by methohexital anesthesia and on the hemodynamic changes induced by retrobulbar block.nnnDESIGNnProspective, randomized, placebo-controlled, double-blind study.nnnSETTINGnUniversity-affiliated, tertiary-care hospital.nnnPATIENTSn60 ASA physical status II and III patients who were admitted for elective cataract extractions and intraocular lens implantations.nnnINTERVENTIONSnPatients were randomly assigned to one of three groups. After adequate preoxygenation in the holding area, Group 1 received alfentanil 5 micrograms/kg intravenously (i.v.), Group 2 received lidocaine 1 mg/kg i.v. and Group 3 received the placebo (saline) i.v. Immediately after the bolus injection of the study solution, sodium methohexital 1.5 mg/kg was injected i.v. over 30 seconds. As soon as the eyelid reflex was lost, the retrobulbar block was placed over 5 seconds.nnnMEASUREMENTS AND MAIN RESULTSnOccurrences of excitatory phenomena were recorded by an independent observer who was blinded as to treatment allocation. Other side effects such as oculocardiac reflex, nausea, vomiting, itching, or chest wall rigidity were recorded. Vital signs were recorded at baseline and 1, 3, and 5 minutes after placement of the block. In the alfentanil group, the incidence of myoclonus or cough was significantly less than in the lidocaine or placebo groups. Alfentanil also decreased systolic and diastolic blood pressure significantly at 1, 3, and 5 minutes after retrobulbar block. Changes in heart rate were not significantly different from baseline.nnnCONCLUSIONnA small dose of alfentanil (5 micrograms/kg i.v.) decreases myoclonus and cough induced by sodium methohexital anesthesia i.v., resulting in improved quality of induction of anesthesia. Alfentanil also attenuates the cardiovascular responses caused by placement of a retrobulbar block.