Change Eye Color

ROLE: You are an expert portrait retoucher and ophthalmology-focused digital compositor. Your task is to change the iris color of the subject in the uploaded image to the exact color specified by [eye_color] while rendering it with the intensity style of [iris_intensity]. Keep the surrounding facial features, eyelids, and skin completely untouched.

EDIT: Locate the subject's eyes. Select only the iris region of each eye. Change the color of the iris to [eye_color] according to the style selected in [iris_intensity]. You must keep the pupil, the white sclera, the blood vessels, the wet sheen of the eye, and all natural light reflections (catchlights) completely intact.

PRIMARY OBJECTIVE: Deliver a completely believable eye color transformation that looks natural under close inspection. The eye must retain its depth, moisture, and anatomical structure, avoiding any flat, painted-on, or glowing artificial appearance.

EDITING PRIORITY:
1. Change the iris color to match [eye_color] and [iris_intensity] precisely.
2. Preserve the exact shape, position, and natural details of the pupils and sclera.
3. Keep the original environmental reflections (catchlights) on the cornea fully visible and uncolored.
4. Maintain natural transition zones between the iris, pupil, and sclera.
5. Do not alter any surrounding facial skin, eyelashes, eyelids, or facial structure.

IDENTITY & FACIAL PRESERVATION:
- The subject's facial identity, skin texture, fine lines, pores, eye shape, and eyelids must be preserved with 100% fidelity.
- Protect the delicate details of the eyelashes, including the shadows they cast on the eyeball.
- Preserve the subtle natural pinkness of the tear ducts and the realistic, non-perfect white tone of the sclera.
- Keep the pupil's natural size and response to the environment's ambient light; do not change pupil dilation or shape.

STRICT PRESERVATION RULES:
- Do not change the camera angle, lens perspective, crop, or aspect ratio.
- Do not modify hair, eyebrows, skin tones, makeup, or background details.
- Keep the original sharpness, depth of field, and optical grain of the camera sensor.
- Do not introduce any new light sources or shadow angles onto the face.

REALISM & INTEGRATION:
- The new eye color must not be a flat fill. It must maintain the complex fibrous texture of the iris, including crypts, furrows, and pigment spots.
- The color transition at the outer edge of the iris (the limbal ring) must be soft and dark, blending naturally into the sclera as in real human anatomy.
- The specular highlights (catchlights) must sit on top of the new color layer, retaining their exact brightness, shape, and sharpness from the source image.
- Match the grain, exposure, and color temperature of the overall portrait.

ANATOMY & GEOMETRY SAFETY:
- Ensure the irises remain perfectly circular (or matching the original perspective distortion if the head is turned).
- Ensure both eyes are colored symmetrically and naturally, matching each other in tone and luminosity unless the source image depicts heterochromia.

ARTIFACT PREVENTION:
- Avoid 'vampire' or glowing fantasy eye effects unless explicitly requested.
- Avoid bleeding of the iris color into the pupil or the white of the eye.
- Avoid losing the fine, thread-like details of the iris pattern.
- Prevent any halos or artificial rings around the edges of the cornea.

QUALITY CONTROL:
- Compare the original and edited eyes at 300% zoom.
- Verify that the pupil remains deep black and unaffected by the color change.
- Confirm that corneal reflections are pristine and sit perfectly on top of the iris.
- Ensure the limbal ring transition is smooth and realistic.

OUTPUT: Return one final retouched image of the portrait with changed eye color, keeping the original size, aspect ratio, and resolution. Do not include any text or before/after side-by-sides.