The state appeals an order that set aside defendant’s conviction, pursuant to ORS 137.225. The issue is whether a conviction for child abuse can be “expunged”1 from one’s criminal record after the effective date of a statutory amendment that expressly prevents convictions for that offense from being set aside. We hold that it cannot, and reverse.
In September, 1986, defendant was convicted of sexual abuse in the first degree. ORS 163.425. The victim was a four-year-old girl. Under the statutory scheme that allows certain convictions to be set aside three years after the successful completion of one’s sentence, the trial court in November, 1989, granted defendant’s motion to set aside his record of the conviction. It concluded that ORS 137.225, as amended in 1989, did not apply to defendant’s conviction.
ORS 137.225(l)(a) provides:
“At any time after the lapse of three years from the date of pronouncement of judgment, any defendant who has fully complied with and performed the sentence of the court and, whose conviction is described in subsection (5) of this section by motion may apply to the court wherein that conviction was entered for entry of an order setting aside the conviction[.]” (Emphasis supplied.)
Before October 3, 1989, ORS 137.225(5)(a) provided:
“The provisions of paragraph (a) of subsection (1) of this section apply to a conviction of:
“(a) A Class C felony.”
In 1989, the legislature amended ORS 137.225(5) to exempt convictions for various crimes involving children. Or Laws 1989, ch 774, § 1. ORS 137.225(5) now provides, in part:
*10“The provisions of paragraph (a) of subsection (1) of this section apply to a conviction of:
“(a) A Class C felony, except for the following crimes when they would constitute child abuse as defined in ORS 418.740.[2]
* * * *
“(D) Sexual abuse in the first degree under ORS 163.425[.]” (Emphasis supplied.)
The state asserts that the trial court erred, because ORS 137.225 no longer allows the court to set aside convictions for Class C felonies involving child abuse and because the legislature intended the 1989 amendments to ORS 137.225 to apply to convictions that were entered before October 3,1989, the effective date of the amendments. Defendant argues that, if the 1989 amendments to ORS 137.225 are applicable to the setting aside of his conviction, the state and federal constitutional prohibitions against ex post facto legislation would be violated. Or Const, Art I, § 21; US Const, Art I, § 10, cl 1.
The threshold issue is whether the legislature intended the 1989 amendments to ORS 137.225 to apply to convictions that occurred before October 3,1989. Generally, when amendments are silent regarding their application to past events, we construe them to apply prospectively only. Olson v. Wheelock, 68 Or App 160, 162, 680 P2d 719 (1984); see also Thornton v. Hamlin, 41 Or App 363, 597 P2d 1307, rev den 288 Or 1 (1979). However, here subsection (8) of the statute unambiguously expresses legislative intent to have ORS 137.225 apply, regardless of the date of conviction. ORS 137.225(8) provides:
“The provisions of subsection (1) of this section apply to convictions and arrests which occurred before, as well as those which occurred after, September 9, 1971. There shall be no time limit for making such applications.”
Because the legislature’s intent is evident from the express language of existing legislation, we need look no further. Whipple v. Howser, 291 Or 475, 483, 632 P2d 782 (1981). *11ORS 137.225 applies to bar the setting aside of defendant’s 1986 conviction.
The next issue is whether the application of amended ORS 137.225 to defendant’s conviction would violate the prohibition against ex post facto laws.3 In the criminal context, an ex post facto law is one that retroactively applies to events that occurred before the law was enacted. It criminalizes acts that were lawful when committed or makes an act a greater crime than when it was committed, changes the elements of the crime or deprives the defendant of a defense, permits conviction on lesser or different evidence than was previously required or increases the quantum of punishment for the crime. See State v. Gallant, 307 Or 152, 155, 764 P2d 920 (1988). Certain changes in the law are not considered ex post facto, even though they may have a deleterious effect on an individual. For example, a change in the evidence code may be retroactively applied to the detriment of a criminal defendant. 307 Or at 155.
Because the statutory change in the present case did not create a new crime, change the proof necessary to establish a crime or deprive defendant of a defense, the only question is whether defendant would be subject to greater punishment for the crime of child abuse, if we gave effect to the legislature’s decision that convictions for that crime may no longer be set aside. Perkey v. Psychiatric Security Review Board, 65 Or App 259, 262, 670 P2d 1061 (1983). In Williams v. Board of Parole, 98 Or App 716, 780 P2d 793 (1989), rev den 309 Or 522 (1990), we found no impermissible ex post facto application because the challenged rules did not “substantially change the procedure for considering the length of [the defendant’s] sentence.” 98 Or App at 721. In Lindsey v. Washington, 301 US 397, 57 S Ct 797, 81 L Ed 1182 (1937), the Supreme Court held that removing the possibility of a sentence that was less than the statutory maximum was an ex post facto law. Similarly, a retroactive elimination of good-*12time credits, which reduced a defendant’s opportunity to shorten his prison sentence, has been ruled impermissible. Weaver v. Graham, 450 US 24, 101 S Ct 960, 67 L Ed 2d 17 (1981). See also Williams v. Board of Parole, 107 Or App 515, 812 P2d 443 (1991). The same logic has been applied to strike down retroactive extensions of probation. State v. Metzler, 72 Or App 555, 696 P2d 576 (1985). In each of those cases, the court was called upon to determine whether the defendant was “subjected to a punishment greater than that to which he was susceptible when he committed the crime.” 72 Or App at 558. In each case, retroactive application of the law constituted impermissible punishment if it increased the length of time that the defendant would remain under the state’s control, decreased the opportunity to have a prison term reduced, or diminished the degree of discretion available to the sentencing judge. See Lindsey v. Washington, supra, 301 US at 401.
It follows that elimination of the set aside remedy for a child abuse conviction is not a “punishment” within the meaning of the Ex Post Facto Clauses of the Oregon and United States Constitutions. The availability of a procedure for sealing one’s criminal record is unrelated to the length or nature of an individual’s incarceration or constructive custody. It does not increase imprisonment, forestall parole or extend probation. It does not decrease the trial judge’s discretion to impose the sentence that is mosf. appropriate for the individual. Further, it is a collateral matter that does not change the primary effect of a conviction. See ABA Project on Standards for Criminal Justice, Standards Relating to Probation, § 4.3 (Approved Draft, 1970).4 In State v. Gallant, supra, 307 Or at 155, the Supreme Court held that certain peripheral effects — such as using a criminal record to impeach a witness —do not impermissibly change a defendant’s punishment or affect any substantive rights and, accordingly, do not amount to an ex post facto law. As Justice Frankfurter wrote in his concurrence to United States v. Lovett, 328 US 303, *13324, 66 S Ct 1073, 90 L Ed 1252 (1946), “[t]he fact that harm is inflicted by governmental authority does not make it punishment. Figuratively speaking all discomforting action may be deemed punishment because it deprives of what otherwise would be enjoyed. But there may be reasons other than punitive for such deprivation.”5
The original intent of the prohibition on ex post facto laws was to prevent vindictive and arbitrary criminal legislation and to provide fair notice of those acts which will subject an individual to criminal sanctions. Dufresne v. Baer, 744 F2d 1543 (11th Cir 1984), cert den 474 US 817 (1985). Both goals are achieved here. The legislative intent behind the amendment to ORS 137.225 was protective, rather than punitive. It sought to retain child sexual abuse convictions in defendants’ criminal records “to protect professions and children where there is a likelihood of some contact with people who have sexual criminal offenses in their records.” Tape recording, Senate Floor Debates, May 8,1989, Side I at 159 (Senator Jim Hill). Allowing daycare centers to discover whether job applicants have been convicted of child abuse does not impose a punishment on criminal defendants. Further, the law does not attempt to “unseal” any previously sealed records. The amendment is reasonably related to a legitimate, nonpunitive governmental objective.
Finally, it should be noted that the social stigma that may attach to an individual with a criminal record is inflicted by the citizenry and the community. The legislature’s decision not to permit setting aside defendant’s conviction for child sexual abuse exposes him to the possible disapproval of his neighbors but cannot constitute the governmental imposition of a “punishment,” in the constitutional sense of that, word. Because the amended statute applies to defendant and does not involve an impermissible ex post facto application of *14the law, we hold that the trial court erred in setting aside the conviction.6
Reversed.
The act of setting aside a conviction is often referred to as an “expungement” or expunction. However, those terms
“should not be used for an order under ORS 137.225(l)(a). That statute does not call for expunging anything from the record of conviction but for sealing the record. ORS 137.225(3). The record of conviction remains available for use in a later proceeding to set aside a conviction of another offense, ORS 137.225(6)(b), in a civil action, ORS 137.225(9) or in an investigation of the movant in a case ‘involving records sealed under this section.’ ORS 137.225(10).” State v. Langan, 301 Or 1, 4 n 3, 718 P2d 719 (1986).
ORS 418.740(l)(c) defines “abuse” to include séxual abuse.
Or Const, Art I, section 21, provides:
“No ex post facto law * * * shall ever be passed * *
US Const, Art I, section 10, provides:
“No state shall * * * pass any * * * ex post facto law * *
The two provisions are “similarly” applied. Howard v. State Board of Parole, 105 Or App 288, 292, 804 P2d 509 (1991).
The ABA’s Probation Standards describe set-aside statutes as “a method by which the collateral effects of a criminal record can be avoided or mitigated following the successful completion of a term on probation * * (Emphasis supplied.) ABA Project on Standards for Criminal Justice, Standards Relating to Probation, supra, at § 4.3.
For example, establishing and later modifying qualifications for the practice of medicine
“is an incident of the State’s power to protect the health and safety of its citizens, and its decision to bar from practice persons who commit or have committed a felony is taken as evidencing an intent to exercise that regulatory power, and not a purpose to add to the punishment of ex-felons.” Flemming v. Nestor, 363 US 603, 616, 80 S Ct 1367, 4 L Ed 2d 1435 (1960). (Citation omitted.)
“The existence of a criminal record is simply a fact of life, not part of the sentence and punishment. Defendant had no constitutionally protected right to assume that the legislative remedy of expungement [sic] was immutable.” State v. T.P.M., 189 NJ Super 360, 460 A2d 167, 171-72 (1983).