Hyperopic shift and the use of masking agents in excimer laser superficial keratectomy.

Liu, C

doi:10.1136/bjo.76.1.62

Cited by 13 publications

(3 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many potential reasons for the hyperopic shift after PTK have been proposed, such as different ablation rates of the underlying pathology, decrease in the angle of incidence of the laser beam on more peripheral corneal areas, corneal centrifugal contraction of superficial collagen lamellae, 17 greater shielding of central cornea by debris, 17 epithelial hyperplasia at the transition zone, 18 and biomechanical response of the cornea secondary to ablation, inducing lamellar relaxation. 19 In contrast, myopic shift in Salzmann's nodular degeneration may be due to the mechanical removal of nodules from the midperipheral cornea, which causes central steepening of the cornea.…”

Section: Discussionmentioning

confidence: 99%

Long-term outcome of excimer laser phototherapeutic keratectomy for treatment of Salzmann's nodular degeneration

Das

Langenbucher

Pogorelov

et al. 2005

Journal of Cataract and Refractive Surgery

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

Long-term outcome of excimer laser phototherapeutic keratectomy for treatment of Salzmann's nodular degeneration

Das

Langenbucher

Pogorelov

et al. 2005

Journal of Cataract and Refractive Surgery

View full text Add to dashboard Cite

show abstract

“…The mean hyperopic shift reported in various studies ranges from 0.87 to 6.4 D. 27,50,55,62,112 Various possible causes include differential ablation rates of normal and abnormal cornea and of central and peripheral cornea, reduced angle of incidence on peripheral cornea, centrifugal contraction of superficial collagen lamellae, shielding of cornea by debris produced by photoablation, epithelial hyperplasia at the transition zone, biomechanical response of cornea secondary to ablation causing lamellar relaxation, and capillary effect caused by masking agents. 8,11,38,51,52,86,105 The use of masking agents dissipates laser energy, resulting in less-than-intended amount of tissue getting ablated. 43 In contrary to the usual hyperopic shift, a myopic shift has been seen in cases with Salzmann nodular degeneration.…”

Section: 2mentioning

confidence: 99%

Phototherapeutic keratectomy

Nagpal

Maharana

Roop

et al. 2020

Survey of Ophthalmology

View full text Add to dashboard Cite

Phototherapeutic keratectomy is an excimer laserebased surgical procedure widely performed by corneal surgeons for treating anterior corneal stromal pathologies. Phototherapeutic keratectomy helps by ablating the corneal stroma, thereby improving corneal clarity and smoothening the surface. Transient discomfort and induced hyperopia from corneal flattening are the immediate postoperative concerns. The long-term course is often marked by the recurrence of original corneal pathology and corneal haze formation. Phototherapeutic keratectomy, however, allows for repeat stromal ablation for managing recurrences, as the corneal thickness permits, without affecting the outcome of future keratoplasty. Adjunctive methods such as topical mitomycin-C may be additionally used to reduce recurrence rates. Also, various masking agents such as carboxymethyl cellulose, sodium hyaluronate, and dextran are used in eyes with irregular corneal surface to allow for uniform stromal ablation. Overall, phototherapeutic keratectomy has provided corneal surgeons an additional surgical tool, particularly those residing in developing nations where the availability of donor corneal tissue is an important limiting factor.

show abstract

“…Techniques to reduce the opacifica tion have also been proposed |8|. Excimer laser-induced corneal scarring can potentially impair some aspects of normal visual function [1,3].…”

Section: Introductionmentioning

confidence: 99%

Computerised Scheimpflug Densitometry as a Measure of Corneal Opacification following Excimer Laser Surgery

Cherny

Stasiuk²,

Kelly

et al. 1994

Ophthalmic Res

View full text Add to dashboard Cite

Some degree of physiological subepithelial opacification can be photographed in all human corneas. In most patients undergoing refractive treatment with an excimer laser further opacification occurs. The Nidek EAS 1000 Anterior Segment Analysis System was used with a 6-mm Scheimpflug slit image in the vertical meridian to photograph both these types of opacities. An image-processing technique was developed to measure corneal opacification quantitatively. A 2.5-mm diameter circle centred on the vertex of the posterior aspect of the corneal image was used as the standard area for analysis. The highest grey scale intensity at which the software demonstrated at least 2% of the analysis area to be opaque is called the corneal opacity index. The average corneal opacity index increased from 70 before treatment to 110 one month after treatment. A comparison with subjective assessment found the corneal opacity index to be the superior method for assessing corneal opacification.

show abstract

Hyperopic shift and the use of masking agents in excimer laser superficial keratectomy.

Cited by 13 publications

References 5 publications

Long-term outcome of excimer laser phototherapeutic keratectomy for treatment of Salzmann's nodular degeneration

Long-term outcome of excimer laser phototherapeutic keratectomy for treatment of Salzmann's nodular degeneration

Phototherapeutic keratectomy

Computerised Scheimpflug Densitometry as a Measure of Corneal Opacification following Excimer Laser Surgery

Contact Info

Product

Resources

About