Noncontact laser photothermal keratoplasty II

Refractive effects and treatment parameters in cadaver eyes

G. Simon, Q. Ren, Jean-Marie A Parel

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

BACKGROUND: Noncontact laser photothermal keratoplasty may provide a new alternative for the treatment of myopia, hyperopia, and astigmatism. The purpose of this article is to study the refractive effect that laser photoablation keratoplasty is capable of producing on a normal human cadaver cornea, including the relationship between the keratometric changes and laser treatment parameters. METHODS: The human cadaver eyes were treated with a holmium laser (pulsed Ho:YAG, 2.10 μm, 250 μs) coupled to a maskable, polyprismatic delivery system mounted on either an optical bench or a slit- lamp microscope. Using a topographic videokeratography system, we first investigated the refractive effect that noncontact laser photothermal keratoplasty would produce on a normal cadaver cornea. We then studied the keratometric changes produced by different radiant exposure levels at a fixed treatment pattern, as well as by different treatment patterns at a fixed radiant exposure level. Finally, we studied the possible therapeutic application of laser photothermal keratoplasty for correcting high postoperative astigmatism on a cadaver eye model. RESULTS: For the single- pulse 3-millimeter ring of eight-spot treatment, the keratometric power of the cornea initially increased with the radiant exposure and peaked at 26 J/cm2. The refractive effect was increased by projecting an additional set of eight spots equidistant between the first eight spots on the same diameter ring. Eighteen J/cm2 was the minimal radiant exposure required to produce consistent and predictable keratometric changes. The corneas were flattened using treatment patterns smaller than or equal to 3 mm in diameter and steepened using treatment patterns larger than or equal to 5 mm in diameter. A transition zone between 4 and 5 mm was observed in which minimal and unpredictable keratometric changes of the central cornea occurred. The surgically-induced astigmatism (>10.00 D) was corrected by progressive laser photothermal keratoplasty treatments. CONCLUSIONS: Laser photothermal keratoplasty can acutely steepen and flatten the cornea in human cadaver eyes.

Original languageEnglish
Pages (from-to)519-528
Number of pages10
JournalJournal of Refractive and Corneal Surgery
Volume10
Issue number5
StatePublished - Jan 1 1994
Externally publishedYes

Fingerprint

Corneal Transplantation
Cadaver
Lasers
Cornea
Astigmatism
Therapeutics
Corneal Topography
Hyperopia
Myopia
Solid-State Lasers

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Noncontact laser photothermal keratoplasty II : Refractive effects and treatment parameters in cadaver eyes. / Simon, G.; Ren, Q.; Parel, Jean-Marie A.

In: Journal of Refractive and Corneal Surgery, Vol. 10, No. 5, 01.01.1994, p. 519-528.

Research output: Contribution to journalArticle

@article{bd981d0c71884181b419b719f9f066ed,
title = "Noncontact laser photothermal keratoplasty II: Refractive effects and treatment parameters in cadaver eyes",
abstract = "BACKGROUND: Noncontact laser photothermal keratoplasty may provide a new alternative for the treatment of myopia, hyperopia, and astigmatism. The purpose of this article is to study the refractive effect that laser photoablation keratoplasty is capable of producing on a normal human cadaver cornea, including the relationship between the keratometric changes and laser treatment parameters. METHODS: The human cadaver eyes were treated with a holmium laser (pulsed Ho:YAG, 2.10 μm, 250 μs) coupled to a maskable, polyprismatic delivery system mounted on either an optical bench or a slit- lamp microscope. Using a topographic videokeratography system, we first investigated the refractive effect that noncontact laser photothermal keratoplasty would produce on a normal cadaver cornea. We then studied the keratometric changes produced by different radiant exposure levels at a fixed treatment pattern, as well as by different treatment patterns at a fixed radiant exposure level. Finally, we studied the possible therapeutic application of laser photothermal keratoplasty for correcting high postoperative astigmatism on a cadaver eye model. RESULTS: For the single- pulse 3-millimeter ring of eight-spot treatment, the keratometric power of the cornea initially increased with the radiant exposure and peaked at 26 J/cm2. The refractive effect was increased by projecting an additional set of eight spots equidistant between the first eight spots on the same diameter ring. Eighteen J/cm2 was the minimal radiant exposure required to produce consistent and predictable keratometric changes. The corneas were flattened using treatment patterns smaller than or equal to 3 mm in diameter and steepened using treatment patterns larger than or equal to 5 mm in diameter. A transition zone between 4 and 5 mm was observed in which minimal and unpredictable keratometric changes of the central cornea occurred. The surgically-induced astigmatism (>10.00 D) was corrected by progressive laser photothermal keratoplasty treatments. CONCLUSIONS: Laser photothermal keratoplasty can acutely steepen and flatten the cornea in human cadaver eyes.",
author = "G. Simon and Q. Ren and Parel, {Jean-Marie A}",
year = "1994",
month = "1",
day = "1",
language = "English",
volume = "10",
pages = "519--528",
journal = "Journal of Refractive Surgery",
issn = "1081-597X",
publisher = "Slack Incorporated",
number = "5",

}

TY - JOUR

T1 - Noncontact laser photothermal keratoplasty II

T2 - Refractive effects and treatment parameters in cadaver eyes

AU - Simon, G.

AU - Ren, Q.

AU - Parel, Jean-Marie A

PY - 1994/1/1

Y1 - 1994/1/1

N2 - BACKGROUND: Noncontact laser photothermal keratoplasty may provide a new alternative for the treatment of myopia, hyperopia, and astigmatism. The purpose of this article is to study the refractive effect that laser photoablation keratoplasty is capable of producing on a normal human cadaver cornea, including the relationship between the keratometric changes and laser treatment parameters. METHODS: The human cadaver eyes were treated with a holmium laser (pulsed Ho:YAG, 2.10 μm, 250 μs) coupled to a maskable, polyprismatic delivery system mounted on either an optical bench or a slit- lamp microscope. Using a topographic videokeratography system, we first investigated the refractive effect that noncontact laser photothermal keratoplasty would produce on a normal cadaver cornea. We then studied the keratometric changes produced by different radiant exposure levels at a fixed treatment pattern, as well as by different treatment patterns at a fixed radiant exposure level. Finally, we studied the possible therapeutic application of laser photothermal keratoplasty for correcting high postoperative astigmatism on a cadaver eye model. RESULTS: For the single- pulse 3-millimeter ring of eight-spot treatment, the keratometric power of the cornea initially increased with the radiant exposure and peaked at 26 J/cm2. The refractive effect was increased by projecting an additional set of eight spots equidistant between the first eight spots on the same diameter ring. Eighteen J/cm2 was the minimal radiant exposure required to produce consistent and predictable keratometric changes. The corneas were flattened using treatment patterns smaller than or equal to 3 mm in diameter and steepened using treatment patterns larger than or equal to 5 mm in diameter. A transition zone between 4 and 5 mm was observed in which minimal and unpredictable keratometric changes of the central cornea occurred. The surgically-induced astigmatism (>10.00 D) was corrected by progressive laser photothermal keratoplasty treatments. CONCLUSIONS: Laser photothermal keratoplasty can acutely steepen and flatten the cornea in human cadaver eyes.

AB - BACKGROUND: Noncontact laser photothermal keratoplasty may provide a new alternative for the treatment of myopia, hyperopia, and astigmatism. The purpose of this article is to study the refractive effect that laser photoablation keratoplasty is capable of producing on a normal human cadaver cornea, including the relationship between the keratometric changes and laser treatment parameters. METHODS: The human cadaver eyes were treated with a holmium laser (pulsed Ho:YAG, 2.10 μm, 250 μs) coupled to a maskable, polyprismatic delivery system mounted on either an optical bench or a slit- lamp microscope. Using a topographic videokeratography system, we first investigated the refractive effect that noncontact laser photothermal keratoplasty would produce on a normal cadaver cornea. We then studied the keratometric changes produced by different radiant exposure levels at a fixed treatment pattern, as well as by different treatment patterns at a fixed radiant exposure level. Finally, we studied the possible therapeutic application of laser photothermal keratoplasty for correcting high postoperative astigmatism on a cadaver eye model. RESULTS: For the single- pulse 3-millimeter ring of eight-spot treatment, the keratometric power of the cornea initially increased with the radiant exposure and peaked at 26 J/cm2. The refractive effect was increased by projecting an additional set of eight spots equidistant between the first eight spots on the same diameter ring. Eighteen J/cm2 was the minimal radiant exposure required to produce consistent and predictable keratometric changes. The corneas were flattened using treatment patterns smaller than or equal to 3 mm in diameter and steepened using treatment patterns larger than or equal to 5 mm in diameter. A transition zone between 4 and 5 mm was observed in which minimal and unpredictable keratometric changes of the central cornea occurred. The surgically-induced astigmatism (>10.00 D) was corrected by progressive laser photothermal keratoplasty treatments. CONCLUSIONS: Laser photothermal keratoplasty can acutely steepen and flatten the cornea in human cadaver eyes.

UR - http://www.scopus.com/inward/record.url?scp=0028113947&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028113947&partnerID=8YFLogxK

M3 - Article

VL - 10

SP - 519

EP - 528

JO - Journal of Refractive Surgery

JF - Journal of Refractive Surgery

SN - 1081-597X

IS - 5

ER -