PRESIDING JUSTICE KNECHT delivered the opinion of the court:

In this interlocutory appeal, plaintiff, Prairie Eye Center, Ltd. (Prairie), seeks reversal of the trial court's order granting in part its motion for a preliminary injunction. Prairie contends it is entitled to complete relief and to force defendant's compliance with the covenant-not-to-compete clause of the parties' employment agreement. We reverse and remand with directions.

BACKGROUND

Defendant, Patrick J. Butler, is an ophthalmologist who specializes in the treatment of glaucoma. In February 1997, Butler entered an employment agreement with Centrum Eye Center, Ltd. Later that year Centrum Eye Center changed its name to Prairie Eye Center and the parties executed a second identical agreement. For three years prior to his employment with Prairie, Butler maintained a clinical practice at the Southern Illinois University School of Medicine (SIU).

The employment agreement between Butler and Prairie contains the following covenant not to compete:

"Upon the expiration or termination of this Agreement, employee covenants that he will not, for a period of two (2) years after expiration or termination, engage in, be associated with or have a financial interest in any medical practice or ophthalmology practice, either directly or indirectly, as employer, employee, principal agent, independent contractor, consultant, partner, stockholder, creditor in any other capacity, at any location(s) within Sangamon County, Illinois[,] or within ten (10) miles of Hillsboro, Illinois[,] and ten (10) miles of any branch office of Employer. * * * Employee acknowledges that Employer has a valid, [protectible] interest in its medical and ophthalmology practice, and that the duration and geographic scope of this covenant are reasonable to protect that interest."

In December 1998, Butler informed Prairie of his intention to terminate his employment and establish a practice in Springfield, Illinois. Butler opened an office approximately two miles from Prairie's Springfield location.

In January 1999, Prairie filed a complaint in the circuit court seeking declaratory relief, permanent injunctive relief, and preliminary injunctive relief. By its claim Prairie sought to enjoin defendant from (1) practicing medicine/ophthalmology at any location within Sangamon County or within 10 miles of its branch offices in Hillsboro, Girard, Rushville, Beardstown, Lincoln, and Decatur; (2) having any association with, or interest in, a practice in the restricted area; (3) soliciting Prairie's patients; and (4) soliciting Prairie's employees. Prairie also sought reasonable attorney fees and any other relief deemed proper by the court.

Two days later, the trial court entered an order granting the injunction in favor of Prairie except as to patients who had a preexisting professional relationship with defendant. While the court acknowledged that courts have consistently found physician employers have a protectible interest in a relationship with their patients, it went on to find:

"By affidavit, the facts here are somewhat different. Defendant came into his employment relationship with Plaintiff with a number of patients who followed him from the medical school. Under the analysis made of '[protectible] business interest' in the cases above cited, it is difficult to find that the restraint of trade normally disfavored by the law is justified as to those patients. To prohibit patients from treating with 'their' doctor would seem to not just inhibit trade, but more importantly denigrate the relationship of doctor and patient."

In so holding, the trial court relied on Dowd & Dowd, Ltd. v. Gleason, 181 Ill. 2d 460, 693 N.E.2d 358 (1998), in which the Supreme Court of Illinois held a covenant not to compete unenforceable between a law firm and two departing attorneys. The trial court acknowledged that the Dowd opinion is based on interpretation of Rule 5.6 of the Rules of Professional Conduct (134 Ill. 2d R. 5.6), which applies exclusively to the legal profession. Nevertheless, the trial court relied on the following quote from Dowd: "The rule is designed both to afford clients greater freedom in choosing counsel and to protect lawyers from onerous conditions that would unduly limit their mobility." Dowd, 181 Ill. 2d at 481, 693 N.E.2d at 369. The trial court found "it is inconceivable that public policy is applicable to only one profession." Thus, the trial court granted the injunction in favor of Prairie, but allowed Butler to continue to treat those patients he acquired through his practice at SIU.

In February 1999, after additional briefing and affidavits from both parties, the trial court reaffirmed its January order. This appeal followed.

ANALYSIS

This appeal is pursuant to Supreme Court Rule 307(a)(1) (166 Ill. 2d R. 307(a)(1)), and thus, the only question properly before us is whether a sufficient showing was made to the trial court to sustain its order granting or denying the relief sought. Postma v. Jack Brown Buick, Inc., 157 Ill. 2d 391, 399, 626 N.E.2d 199, 203 (1993). An appeal under this rule may not be used "as a vehicle to determine the merits of a plaintiff's case." Postma, 157 Ill. 2d at 399, 626 N.E.2d at 203. Trial courts have substantial discretion in deciding whether to grant a temporary injunction (Danville Polyclinic, Ltd. v. Dethmers, 260 Ill. App. 3d 108, 109, 631 N.E.2d 842, 843 (1994)), and the decision of the trial court will not be disturbed on appeal absent an abuse of discretion (Weitekamp v. Lane, 250 Ill. App. 3d 1017, 1022, 620 N.E.2d 454, 458 (1993)).

As a general rule, a preliminary injunction will only be granted where the plaintiff shows it (1) has a clearly ascertainable right that needs protection, (2) will suffer irreparable harm without the protection, (3) has no adequate remedy at law, and (4) is likely to succeed on the merits. Postma, 157 Ill. 2d at 399, 626 N.E.2d at 204. This court has also considered whether the benefits of granting the preliminary injunction will exceed the injury to the defendant. Danville, 260 Ill. App. 3d at 111, 631 N.E.2d at 844; Sarah Bush Lincoln Health Center v. Perket, 238 Ill. App. 3d 958, 961, 605 N.E.2d 613, 616 (1992). A plaintiff need only make a prima facie showing of evidence on the requisite elements to obtain injunctive relief. Weitekamp, 250 Ill. App. 3d at 1022, 620 N.E.2d at 458.

Because Illinois courts abhor restraints on trade, restrictive covenants are carefully scrutinized. Gillespie v. Carbondale & Marion Eye Centers, Ltd., 251 Ill. App. 3d 625, 626, 622 N.E.2d 1267, 1269 (1993). Though generally restraints of trade are held void, where the limitation as to time and territory is not unreasonable, a restrictive covenant is valid and enforceable, and relief by injunction is customary and proper. Canfield v. Spear, 44 Ill. 2d 49, 50-51, 254 N.E.2d 433, 434 (1969). In determining whether to grant an injunction enforcing a restrictive covenant, courts look to whether the covenant is reasonable (Weitekamp, 250 Ill. App. 3d at 1023, 620 N.E.2d at 459) and valid (Retina Services, Ltd. v. Garoon, 182 Ill. App. 3d 851, 855, 538 N.E.2d 651, 652 (1989)).

Prairie contends the trial court abused its discretion when it improperly relied on the public policy rationale articulated in Dowd and asks this court to decide whether the Dowd holding applies outside the legal profession and renders noncompete covenants between professionals unenforceable. A finding so broad, however, is not necessary to resolve the issue raised by this appeal. Regardless of its rationale, the trial court found Prairie failed to show it has a protectible interest in all of the patients Butler treated while in its employ. We disagree with the trial court's conclusion and find, under existing precedent, Prairie presented sufficient evidence of a protectible interest to satisfy its burden and secure a preliminary injunction against Butler.

Butler contends his situation is unique and distinguishable from the line of cases upholding restrictive covenants between medical professionals when the time restriction and geographic scope are reasonable. According to Butler's affidavit, as of January 1999, 60% of the patients he was treating at Prairie had been his patients at SIU, and he contends Prairie has no protectible interest in those patients. Butler cites no authority to support his position but argues the existing case law should not apply to him. Butler contends the existing case law developed to protect established physician employers from newcomers to the profession who, upon joining the practice, could build a relationship with the existing patient base, and then usurp those patients upon leaving the practice. Ergo, because Butler was not a newcomer to the profession or a "potential usurper" when he was hired by Prairie, these cases are inapplicable and we should consider his as a case of first impression. We are not persuaded. While the facts of this case are unique, analogous cases do exist.

As Butler suggests, most recent published cases involve an employer suing to enforce a restrictive covenant to prevent a newcomer to an existing and established practice from raiding that practice's client base upon his or her eventual departure. However, in Bauer v. Sawyer, 8 Ill. 2d 351, 134 N.E.2d 329 (1956), the circumstances of the departing physician's employment were similar to Butler's. In Bauer, the dispute arose between a professional partnership and Sawyer, an original founding member of the partnership, when Sawyer left the practice and the partnership sought to enforce the covenant-not-to-compete provision of the partnership agreement. Sawyer argued because he was not a newcomer to the practice or a potential usurper of the partnership's patients, the restrictive covenant should not be enforced. Bauer, 8 Ill. 2d at 356, 134 N.E.2d at 332. The Supreme Court of Illinois rejected this argument and held:

"No case is cited which holds that the members of a partnership may not by their agreement reasonably protect themselves against the competition of an outgoing partner. Indeed such agreements are classic illustrations of reasonable restraints of trade. 'A legitimate method of enhancing the good will of continuing partners in professional, as well as commercial, partnerships is to secure forbearance from competition by a retired partner.'" Bauer, 8 Ill. 2d at 356, 134 N.E.2d at 332, quoting J. Crane, Partnerships