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Biomedical subjects

W J Stark

Publications and source records attributed to W J Stark.

At least 109 records · Page 6Linked to original sources
PubMed1989

Endophthalmitis due to Propionibacterium acnes sequestered between IOL optic and posterior capsule.

A 68-year-old woman had delayed onset, persistent uveitis following routine extracapsular cataract extraction with posterior chamber intraocular lens implantation. The patient initially responded to topical steroids, but developed a whitish capsular plaque through to represent possible Propionibacterium acnes endophthalmitis. A vitrectomy and capsular biopsy yielded cultures positive for P. acnes only after nine days. The intraocular lens was left in place. Light and electron microscopy revealed bacteria sequestered within the capsular bag.

Aged↗
PubMed1988

Corneal graft survival in the cat with prolonged preservation in McCarey-Kaufman and K-Sol media.

The effects of extended preservation on transplanted corneas were investigated using McCarey-Kaufman (M-K) and K-Sol media. Cat corneas were preserved in either M-K or K-Sol at 4 degrees C for 5, 10, 15, or 20 days and were subsequently transplanted. Postoperatively, transplants were observed via slit-lamp biomicroscopy and pachymetry and at postmortem examination by light and scanning electron microscopy. In this study, we found no difference in the corneal graft clarity, thickness, endothelial cell count, or morphologic features of corneal transplants preserved in either M-K or K-Sol media. Storage for more than ten days in either M-K or K-Sol media led to primary graft failure. This study demonstrated equivalent results in corneal preservation using either M-K or K-Sol media. The development of better preservation media may require changes in essential nutrients rather than changes in osmotic constituents.

Animals↗
PubMed1988

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.

Aged↗
PubMed1988

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.

Adolescent↗
PubMed1988

Corneal alanine metabolism demonstrated by NMR spectroscopy.

This study confirms the feasibility of monitoring corneal metabolism of an amino acid using high resolution NMR spectroscopy. Alanine metabolism to lactate was detected in intact, freshly isolated rabbit corneas. Progressively decreasing alanine resonances were noted after 4-5 hours of incubation while increasing amounts of lactate were detected. No similar signal was noted in de-epithelialized tissue. This study demonstrates the ability of corneal epithelium to utilize alanine as a metabolic substrate. This technique may be useful to determine the essential amino acids and their optimal concentrations necessary to maintain corneal viability during storage.

Alanine↗
PubMed1988

In vitro immunological function of human corneal fibroblasts.

Gamma-interferon-induced HLA-DR-like antigens on normal human fibroblasts were compared functionally to HLA-DR antigens on peripheral blood mononuclear leucocytes (PBML) from the same individual. Irradiated DR+ fibroblasts did not stimulate allogeneic PBML to divide in a mixed lymphocyte fibroblast culture (MLFC) as determined by 3H-thymidine incorporation, although lymphocytes autologous to the fibroblasts stimulated normally. Co-culture with interleukin 1 (IL-1), IL-2, 2-mercaptoethanol and indomethacin had no effect on MLFC. Pretreatment of stimulator fibroblasts with neuraminidase to modify sialoglycoproteins increased responses only modestly. Both DR+ and DR- fibroblasts inhibited a normal mixed lymphocyte culture (MLC) response in a dose-dependent fashion. These results suggest that the induction of HLA-DR-like molecules on fibroblasts is not sufficient to initiate host sensitization and that fibroblasts may inhibit normal lymphoproliferation.

Cell Cycle↗
PubMed1988

Keratoconus. Contact lens or keratoplasty?

The success rate of contact lens fitting and rate of progression to keratoplasty were evaluated for 115 consecutive patients with keratoconus. Of 190 nonoperated eyes that needed to be fit, 25 (13%) could not be fit, whereas 165 eyes (87%) could be fit. Most of these eyes had been referred for keratoplasty after previous contact lens fittings had no longer been successful. Of the 165 eyes that could be fit, 51 (31%) ultimately needed keratoplasty after an average of 38.4 months of lens wear, and 114 eyes (69%) did not require keratoplasty over an average follow-up interval of 63 months of wearing contact lenses. The average initial keratoplasty reading in these two groups was 56.8 and 51.8 diopters (D), respectively. Special design, bispheric lenses were required in 125 of these 165 eyes (76%) and frequent lens changes were necessary. Of 88 postoperative eyes, 53 (60%) wore contact lenses for best vision. Keratoplasty can be delayed or avoided in many keratoconus patients by using contact lenses, especially special design, bispheric lenses. Also, keratoconus eyes often need contact lenses after keratoplasty.

Adolescent↗
PubMed1988

Posterior chamber intraocular lens implantation in the absence of posterior capsular support.

Because of the high incidence and great variety of complications associated with anterior chamber intraocular lenses, we have developed a technique for the implantation of a posterior chamber intraocular lens in the absence of posterior capsular support. The posterior chamber IOL is placed in the ciliary sulcus by suturing the superior haptic to the iris and the inferior haptic to the sclera at the ciliary sulcus. We have used this technique successfully in both complicated extracapsular surgery and secondary intraocular lens implantation.

Cataract Extraction↗
PubMed1987

Complications of semiflexible, closed-loop anterior chamber intraocular lenses.

Anterior chamber intraocular lenses (IOLs) provided good visual rehabilitation of aphakia in a majority of patients. An increasing number of eyes with closed-loop, semiflexible anterior chamber implants are now being seen with decreased vision due to corneal edema and persistent cystoid macular edema. We evaluated 53 such eyes in 52 patients who presented with decreased vision one to 51 months (average, 15 months) after lens implantation. The most frequent lens implanted was the Surgidev Style 10 Leiske IOL. Surgery for IOL removal or exchange with or without penetrating keratoplasty was performed in 34 (64%) of 53 eyes; visual acuity recovery ranged from 20/20 to hand motions (average, 20/80). Despite clear corneal grafts in 24 (92%) of the 26 eyes that underwent corneal transplantation, visual acuity of 20/40 or better was obtained in only nine eyes (26%). Based on the intractable inflammatory sequelae associated with anterior chamber closed-loop IOLs, we strongly urge discontinuation of their use.

Aged↗
PubMed1987

Use of posterior chamber lenses in pseudophakic bullous keratopathy.

The occurrence of pseudophakic bullous keratopathy following anterior chamber intraocular lens implantation is well documented. At the time of penetrating keratoplasty and anterior chamber intraocular lens removal, we attempt to reimplant a posterior chamber lens whenever possible because of the complications associated with anterior chamber lenses. We developed a technique to exchange an anterior chamber lens with a posterior chamber lens during penetrating keratoplasty. The intraocular lens loops are inserted in the ciliary sulcus and the optic is sutured to the iris.

Anterior Chamber↗
PubMed1987

Refractive keratoplasty for disabling astigmatism after penetrating keratoplasty.

Postoperative astigmatism is one of the major limitations of penetrating keratoplasty. In an attempt to reduce postkeratoplasty astigmatism, we combined corneal-relaxing incisions with orthogonal compression sutures, guided by the intraoperative use of a ring keratometer. Eleven consecutive patients from a mixed referral population with functionally disabling astigmatism were studied. The average preoperative keratometric cylinder of 11.68 diopters was reduced by 7.95 (+/- 3.03 SD) diopters. Each patient's net keratometric cylinder was reduced. We believe that this technique is safer and more predictable than previously published techniques.

Astigmatism↗