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Biomedical subjects

K J Hoffer

Publications and source records attributed to K J Hoffer.

70 records · Page 4Linked to original sources
PubMed1979

An Impressive Result: AIR.

Results of endothelial photography indicate the occasional disregard for implant-corneal touch that may occur during many intraocular maneuvers. The use of air reduces this risk and undoubtedly can give the physician an impressive result.

Air↗
PubMed1978

A cell membrane theory of endothelial repair and vertical cell loss after cataract surgery.

Endothelial cell counts were taken of the superior, central and inferior corneas of controls, immediate post-operative cases and a four year post-operative case. A vertical mean cell density was found to correlate well with central densities, and mean vertical cell loss (42%) compared well with central cell loss (44%). There was no trend for vertical cell disparity (VCD) in control eye, but a definite disparity was seen in all post-operative eyes, including the one four years after surgery. A cell membrane stimulus theory is proposed for endothelial cell reparation after endothelial damage describing cessation of cell migration once the defect is covered.

Cataract Extraction↗
PubMed1978

Survey on the use of intraocular lenses.

A birth of interest in lens implantation occurred especially in the United states in 1974. This coincides with the beginning of four major American lens manufacturers. This interest expoded in 1975 and 1976 and seems to be continuing to grow. Only a few surgeons have stopped implants, most of them after having done ten or less. Half of the surgeons now doing implants have done 25 or less, while 40% have performed a series of 25 to 200. Intracapsular lens styles were the most often used, and the Worst Medallion lens was by far the most popular. Medical Workshop was the leading supplier of lens implants. Accounting for 25%, and European lenses were more often used (61%). The majority of surgeons beginning lens implants after 1974 used either American lenses exclusively or both sources. The majority of lenses used were designed by Binkhorst and Worst. Only 4% of lenses implanted were done secondarily, but one third of the surgeons have performed this procedure; more do them as their experience grows. An overall visual acuity of 20/40 or better postoperatively was found in 83.8% of cases. Significant lens power errors were rare but increased with increasing experience. One third of the surgeons have reported removing a lens implant at a rate of 0.8%, but only 3% of the surgeons have reported removing an eye with a lens implant at a rate of 0.05%.

Aphakia, Postcataract↗
PubMedDate not supplied

Preoperative evaluation of the cataractous patient.

The author reviews the methods and considerations involved in evaluating the cataractous patient. A well documented work-up is essential both to determine the need for surgery and to be able to inform the patient of possible outcomes. Many subjective factors influencing the decision to operate are also taken into account. The decision must be made on the basis of the work-up, a complete evaluation of the patient's complaints, lifestyle, and needs, and consideration of the risk factors involved. Indications and contraindications for intraocular lens implantation are examined. The subject of calculating lens power is covered in detail. The use of endothelial cell counts is also examined.

Cataract↗
PubMedDate not supplied

Intraocular lens power calculation for eyes after refractive keratotomy.

BACKGROUND: Calculating the intraocular lens (IOL) power for an eye that has previously had refractive keratotomy is a problem because of the difficulty of accurately measuring the central power of the cornea using standard keratometers. METHODS: Three methods are proposed to better estimate this parameter. The clinical history method involves subtracting the change in myopia induced by the refractive keratotomy from the average corneal power measured before the keratotomy. The contact lens method determines the difference between the manifest refraction with and without a plano hard contact lens of known base curve and subtracts this difference from that base curve. Videokeratography measures the central corneal power inside the approximately 3-mm zone measured by keratometry, and therefore gives a more accurate power to use in IOL calculation formulas, especially with newer software applications becoming available. RESULTS: Published reports have demonstrated that standard keratometers do not accurately measure corneal power after refractive keratotomy and that regression formulas are less accurate than modern third-generation theoretic formulas for eyes that have flatter corneas from refractive surgery. CONCLUSION: For eyes that have had refractive surgery, the corneal power derived from clinical history, contact lens refraction, or videokeratography should be used in a third-generation theoretic formula (Hoffer Q, Holladay, SRK/T) to calculate the intraocular lens power used during cataract surgery.

Contact Lenses↗