==================================HSR47==================================
47.  Safety and effectiveness of radial keratotomy.
1
UI  - 87066189
AU  - Deitz MR ; Sanders DR ; Raanan MG
TI  - Progressive hyperopia in radial keratotomy. Long-term follow-up of
      diamond-knife and metal-blade series.
AB  - In an earlier report, the authors demonstrated a trend toward progressive
      hyperopia in radial keratotomy (RK) patients examined between one and
      three to four years postoperatively. In those 109 cases, the surgeries
      were performed using a metal-blade instrument. In the following study,
      the metal-blade series was updated to a total of 225 procedures, and a
      more recent series of 300 procedures performed on 228 patients was
      examined in which a diamond-knife cutting instrument was used. Patients
      had uncorrected visual acuity determination, cycloplegic refractions with
      best corrected visual acuity measurements and keratometry measurements.
      The authors demonstrated a hyperopic shift in the distribution of
      postoperative spherical equivalent (SE) values across time such that
      higher proportions of cases in both metal-blade and diamond-knife series
      were at least 1.0 diopter (D) away from emmetropia at 24 and 48 months
      than was the case at 12 months after surgery. Regression analysis
      determined that none of the preoperative or surgical variables known to
      affect refractive outcome of RK (alone or in combination) could account
      for the changes in refraction seen during the course of postoperative
      time. In general, changes in keratometry paralleled refractive changes,
      but were somewhat smaller in magnitude.
MH  - Cornea/*SURGERY ; Follow-Up Studies ; Human ; Hyperopia/*ETIOLOGY/
      PHYSIOPATHOLOGY ; *Postoperative Complications ; Refraction, Ocular ;
      *Surgical Instruments ; Time Factors
SO  - Ophthalmology 1986 Oct;93(10):1284-9
2
UI  - 87060558
AU  - Shepard DD
TI  - Radial keratotomy: analysis of efficacy and predictability in 1,058
      consecutive cases. Part I: Efficacy.
AB  - Effectiveness and predictability of anterior radial keratotomy to correct
      myopia and astigmatism or astigmatism alone were evaluated in 1,058
      consecutive surgeries. The surgical technique consisted of retrobulbar
      anesthetic injection, topical anesthetic, from four to 32 radial
      incisions with a diamond blade, cutting from the optic zone to the
      limbus, optical clear zone diameter from 2.75 mm to 5.00 mm, longitudinal
      or tangential incisions, if necessary, to correct astigmatism, and
      bilateral surgery at the same sitting in 72% of cases. There were 816 of
      1,018 subjects (80.2%) between +/- 1 diopter (D) of emmetropia following
      surgery; 86.1% of 1,003 eyes were 20/40 or better uncorrected
      postoperatively; mean astigmatism was reduced from 0.97 D preoperatively
      to 0.66 D postoperatively. Sixty-seven eyes (6.3%) had microperforations;
      seven (0.7%) had macroperforations requiring a suture. The mean change in
      refraction for patients with and without perforations was 5.43 D and 4.20
      D, respectively.
MH  - Astigmatism/SURGERY ; Evaluation Studies ; Human ; *Keratotomy, Radial ;
      Myopia/SURGERY ; Postoperative Complications ; Postoperative Period ;
      Prognosis ; Refraction, Ocular ; Vision ; Visual Acuity
SO  - J Cataract Refract Surg 1986 Nov;12(6):632-43
3
UI  - 86305515
AU  - Werner DL
TI  - Refractive surgery: keratomileusis and keratophakia.
AB  - This paper reviews the non-radial keratotomy surgeries that are being
      performed. The author reviews the literature and suggests an approach
      toward counseling patients who may be considering these approaches. The
      paucity of reported studies makes the choice of these alternate
      procedures somewhat risky, particularly in their refractive
      predictability.
MH  - Cornea/*SURGERY/TRANSPLANTATION ; Evaluation Studies ; Forecasting ;
      Human ; Myopia/PHYSIOPATHOLOGY/SURGERY ; Postoperative Complications ;
      Refraction, Ocular ; Refractive Errors/PHYSIOPATHOLOGY/SURGERY ; Visual
      Acuity
SO  - J Am Optom Assoc 1986 Aug;57(8):590-3
4
UI  - 86305513
AU  - Ajamian PC
TI  - Radial keratotomy: an overview.
AB  - Radial keratotomy is a controversial procedure to eliminate or reduce
      myopia. It is being performed on a more frequent basis in this country,
      making it mandatory that all doctors of optometry become familiar with
      the operation. I begin with a brief history of the procedure, and discuss
      results of the Prospective Evaluation of Radial Keratotomy (PERK) study,
      as well as complications that patients need to be informed of.
MH  - Cornea/*SURGERY ; Human ; Medical Illustration ; Myopia/PHYSIOPATHOLOGY/
      *SURGERY ; Postoperative Complications ; Prospective Studies ;
      Refraction, Ocular ; Reoperation ; Surgical Wound Infection
SO  - J Am Optom Assoc 1986 Aug;57(8):580-2
5
UI  - 86286100
AU  - Salz JJ ; Villase:nor A ; Elander R ; Reader AL 3d ; Swinger C ;
      Buchbinder M
TI  - Four-incision radial keratotomy for low to moderate myopia.
AB  - The first 112 consecutive eyes (75 patients) to undergo four-incision
      radial keratotomy (RK) performed by four surgeons were evaluated
      retrospectively. The preoperative myopia (spherical equivalent) ranged
      from -1.12 to -7.00 D (95% between -1.12 and -4.25 D). The preoperative
      uncorrected visual acuity was 20/100 or worse in 95% of the eyes. A
      six-month follow-up was achieved in 95% of the eyes and 45% were followed
      over one year. Following four incision RK, 79% of the eyes achieved 20/40
      or better vision and 82% were corrected to within 1 D of emmetropia.
      Following repeat RK in 15 eyes (13%), 82% had uncorrected visual acuity
      of 20/40 or better, and 90% were corrected to within 1 D of emmetropia.
      Only 3.5% of the eyes were overcorrected by more than 1 D and only one
      eye had induced astigmatism greater than 1 D. For eyes with preoperative
      myopia up to -4.25 D over 90% achieved uncorrected visual acuity of 20/40
      or better and were within 1 D of emmetropia following primary four
      incision RK and a second four incisions in 13 eyes (12%). Only 3.5% of
      the eyes in this group were overcorrected by more than 1 D. There were no
      serious complications.
MH  - Adult ; Aged ; Astigmatism/PHYSIOPATHOLOGY ; Comparative Study ; Cornea/
      *SURGERY ; Female ; Human ; Male ; Middle Age ; Myopia/PHYSIOPATHOLOGY/
      *SURGERY ; Postoperative Complications ; Postoperative Period ;
      Reoperation ; Retrospective Studies ; Vision Tests ; Visual Acuity
SO  - Ophthalmology 1986 Jun;93(6):727-38
6
UI  - 86286099
AU  - Merck MP ; Williams PA ; Lindstrom RL
TI  - Trapezoidal keratotomy. A vector analysis.
AB  - Twenty-three eyes in 23 patients ranging from 61 to 83 years of age
      underwent trapezoidal astigmatic (Ruiz) keratotomy. Preoperative regular
      astigmatism ranged from 3.13 to 13.00 diopters by keratometry. Fourteen
      of the eyes had high regular astigmatism following penetrating
      keratoplasty, eight following cataract extraction, and one eye had no
      history of surgery. Patient follow-up ranged from 1 to 15 months with a
      mean of five months. Trigonometric vector analysis of the keratometric
      readings demonstrated that the magnitude of surgically induced change in
      corneal curvature was inversely proportional to the size of the optical
      zone and ranged from 1.28 to 14.21 diopters. Frequently, due to the axis
      of surgically induced change, the magnitude of change in corneal
      curvature failed to be reflected by an equal magnitude of reduction in
      the residual corneal astigmatic error, and in many cases a residual error
      was created in a meridian differing significantly from that of the
      preoperative astigmatic error. There is no statistically significant
      difference in the slopes of the linear regression lines relating change
      in corneal curvature to optical zone size between this series and our
      previously reported cadaver study.
MH  - Aged ; Astigmatism/CONGENITAL/ETIOLOGY/PHYSIOPATHOLOGY/SURGERY ; Cataract
      Extraction ; Comparative Study ; Cornea/PATHOLOGY/*SURGERY ; Human ;
      Middle Age ; Postoperative Complications ; Retrospective Studies ;
      Support, Non-U.S. Gov't
SO  - Ophthalmology 1986 Jun;93(6):719-26
7
UI  - 86211807
AU  - Lundergan MK ; White GL Jr ; Murdock RT
TI  - What patients should know about radial keratotomy.
AB  - Radial keratotomy is a relatively new, widely advertised procedure that
      promises patients with myopia 20/20 vision without corrective lenses.
      However, radial keratotomy sometimes does not fulfill this promise. New
      studies have reported numerous cases in which patients were not helped or
      were actually harmed by radial keratotomy. Also, its long-term effects
      are unknown. Family physicians should advise patients to approach the
      procedure with caution.
MH  - Cornea/*SURGERY ; Human ; Light ; Myopia/*SURGERY ; Physicians, Family ;
      Postoperative Complications/*ETIOLOGY ; Risk ; Time Factors ; Vision
      Disorders/ETIOLOGY
SO  - Am Fam Physician 1986 May;33(5):169-72
8
UI  - 86204772
AU  - Villase:nor RA ; Santos VR ; Cox KC ; Harris DF 2d ; Lynn M ; Waring GO
      3d
TI  - Comparison of ultrasonic corneal thickness measurements before and during
      surgery in the prospective evaluation of Radial Keratotomy (PERK) Study.
AB  - Central corneal thickness, determined by an ultrasonic pachymeter, was
      studied in one eye each of 395 patients enrolled in the Prospective
      Evaluation of Radial Keratotomy (PERK) Study, to determine the changes in
      central corneal thickness between preoperative and intraoperative
      measurements. There was no statistical difference between the
      preoperative and the intraoperative measurement. However, 9.4% of the
      corneas were 0.03 to 0.08 mm thinner intraoperatively and 3.3% were 0.03
      to 0.06 mm thicker intraoperatively, indicating that clinically
      meaningful changes in corneal thickness occurred between the preoperative
      and intraoperative measurements in some eyes. We conclude that the most
      reliable way to use ultrasonic pachymetry readings to set the length of
      the knife blade for radial keratotomy surgery is to measure the corneal
      thickness intraoperatively.
MH  - Comparative Study ; Cornea/PATHOLOGY/*SURGERY ; Human ; Intraoperative
      Period ; Preoperative Care ; Prospective Studies ; Support, U.S. Gov't,
      P.H.S. ; Time Factors ; *Ultrasonic Diagnosis
SO  - Ophthalmology 1986 Mar;93(3):327-30
9
UI  - 86163786
AU  - Atkin A ; Asbell P ; Justin N ; Smith H ; Wayne R ; Winterkorn J
TI  - Radial keratotomy and glare effects on contrast sensitivity.
AB  - After radial keratotomy (RK) to correct myopia, some patients complain of
      'glare'. Effects of a glare source on contrast sensitivity were measured
      in fifteen patients after unilateral RK. With each eye, determinations
      were made of the contrast required for detection of steady gratings
      (spatial frequencies of 0.7 and 2.9 cycles/deg), and for detection of
      flicker (unpatterned field flickering at rates of 8, 16, and 32 Hz).
      Grating or flicker was presented on a centrally fixated 4 deg test target
      (34 cd/m2 mean luminance), surrounded by a diffuse glare source (1700
      cd/m2 mean luminance). For each stimulus, contrast thresholds were
      determined with glare-source off and with glare-source on. 'Glare loss'
      was defined as the decrement in contrast sensitivity measured with the
      glare source on. Significant findings were: (1) Both eyes showed glare
      losses for detection of gratings and for detection of flicker; (2)
      Spectacle lenses increased glare losses both for gratings and for
      flicker; (3) The RK eye showed a larger glare loss for flicker than the
      unoperated eye, but a smaller glare-loss for gratings; (4) For both
      flicker and gratings, glare loss tended to be greater in the RK eye,
      compared to the unoperated eye, in subjects who had larger pupil
      diameters in the testing situation; (5) The psychophysical measurements
      obtained in this study were not significantly correlated either with a
      questionnaire index of glare complaints or with the score obtained with
      the Miller-Nadler GlareTester.
MH  - Adult ; Aging ; Cornea/*SURGERY ; Eye/PHYSIOPATHOLOGY ; Female ; Human ;
      Male ; Mathematics ; Photic Stimulation ; Postoperative Complications ;
      Prospective Studies ; Pupil ; Support, U.S. Gov't, P.H.S. ; *Vision ;
      Vision Tests
SO  - Doc Ophthalmol 1986 Feb 28;62(2):129-48
10
UI  - 86158441
AU  - Bourque LB ; Cosand BB ; Drews C ; Waring GO 3d ; Lynn M ; Cartwright C
TI  - Reported satisfaction, fluctuation of vision, and glare among patients
      one year after surgery in the Prospective Evaluation of Radial Keratotomy
      (PERK) Study.
AB  - We studied satisfaction with the results of radial keratotomy one year
      after surgery on one eye as reported by 354 patients in the Prospective
      Evaluation of Radial Keratotomy (PERK) Study. We measured satisfaction
      using an index based on ten questions that were part of a longer
      psychometric questionnaire. Patients were generally satisfied with the
      results of radial keratotomy-48% were very satisfied, 42% were moderately
      satisfied, and 10% were dissatisfied. A lot of trouble with fluctuating
      vision was reported by 12% of patients before surgery and by 34% one year
      after surgery; 17% reported a lot of trouble with glare both before
      surgery and one year after surgery. The three major factors that
      influenced satisfaction were uncorrected visual acuity, residual
      refractive error, and subjective daily fluctuation in vision. A multiple
      regression equation that incorporated these three variables, glare, and
      patient sex was able to predict only 46% of the variance in patient
      satisfaction.
MH  - Adult ; Comparative Study ; Consumer Satisfaction ; Cornea/*SURGERY ;
      Evaluation Studies ; Female ; Human ; Male ; Middle Age ; Myopia/*SURGERY
      ; Postoperative Complications/OCCURRENCE ; Prospective Studies ;
      Psychometrics ; Refractive Errors/OCCURRENCE ; Sex Factors ; Support,
      U.S. Gov't, P.H.S. ; Vision Disorders/OCCURRENCE ; Visual Acuity
SO  - Arch Ophthalmol 1986 Mar;104(3):356-63
11
UI  - 86147883
AU  - Schanzlin DJ ; Santos VR ; Waring GO 3d ; Lynn M ; Bourque L ; Cantillo N
      ; Edwards MA ; Justin N ; Reinig J ; Roszka-Duggan V
TI  - Diurnal change in refraction, corneal curvature, visual acuity, and
      intraocular pressure after radial keratotomy in the PERK Study.
AB  - Selected patients who complained of fluctuating visual acuity in the
      Prospective Evaluation of Radial Keratotomy (PERK) Study were examined
      before 8:00 a.m. and after 7:00 p.m. on the same day to determine diurnal
      change in uncorrected visual acuity, best corrected visual acuity,
      manifest refractive error, average central keratometric power, and
      intraocular pressure. Sixty-three operated eyes were examined at three
      months, while 46 operated and 40 unoperated contralateral eyes were
      examined at one year after radial keratotomy. One year after surgery, 42%
      of the operated eyes had an increase in minus power of the manifest
      refraction of 0.50 to 1.25 diopters, 26% of the eyes changed their
      uncorrected visual acuity by 2 to 4 Snellen lines, and 35% of the
      operated eyes showed central steepening of the cornea by 0.50 to 1.25
      diopters. These changes in the operated eyes at one year were similar to
      the changes at three months. Minimal diurnal changes occurred in the
      unoperated eyes at one year. Only 11% of the unoperated eyes changed
      their manifest refraction by 0.50 to 1.00 diopters, none changed their
      uncorrected visual acuity by 2 to 4 Snellen lines, and only one of the
      unoperated eyes changed its central keratometric power by 0.50 diopters.
      This study documents that many patients who experience diurnal
      fluctuation of vision have steepening of the cornea and an increase in
      the minus power of their refraction during the day.
MH  - Biomechanics ; *Circadian Rhythm ; Cornea/PATHOLOGY/*SURGERY ; Evaluation
      Studies ; Human ; *Intraocular Pressure ; Refractive Errors/
      *PHYSIOPATHOLOGY ; Support, U.S. Gov't, P.H.S. ; Vision/PHYSIOLOGY ;
      *Visual Acuity
SO  - Ophthalmology 1986 Feb;93(2):167-75