Simple eye follow for unity using DoTween for blink (you can comment them if you dont want to blink with tween)

EyeFollow.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using DG.Tweening;

public class EyeFollow : MonoBehaviour
{
    [SerializeField] Transform[] insideEyes;
    [SerializeField] float EyeRadius;
    [SerializeField] int updateInterval = 3;
    [Tooltip("Set target for eyes use null to follow mouse/touch")]
    [SerializeField] Transform target;
    private Camera _camera;
    private float randomBlinkTime;
    private float ellapsedTime;
    private float startScaleY;
    private bool centered;

    private void Awake()
    {
        _camera = Camera.main;
        randomBlinkTime = Random.Range(1f, 4f);
        ellapsedTime = 0;
        startScaleY = transform.localScale.y;
    }

    public void SetTarget(Transform target)
    {
        this.target = target;
    }

    void Update()
    {
        ellapsedTime += Time.deltaTime;
        if (hasInput)
        {
            if (Time.frameCount % updateInterval == 0)
            {
                centered = false;
                foreach (var insideEye in insideEyes)
                    insideEye.localPosition = EyeRadius * (targetPosition - insideEye.position).normalized;
            }
        }
        else if (releaseInput)
        {
            if (!centered)
            {
                centered = true;
                foreach (var insideEye in insideEyes)
                    insideEye.localPosition = Vector3.zero;
            }
        }
        if (ellapsedTime > randomBlinkTime)
        {
            ellapsedTime = 0;
            randomBlinkTime = Random.Range(1f, 4f);
            var tween = transform.DOScaleY(0, 0.05f);
            tween.onComplete += () =>
            {
                var scaleUpTween = transform.DOScaleY(startScaleY, 0.3f);
                scaleUpTween.SetEase(Ease.OutQuart);
            };
        }
    }


    private Vector3 targetPosition
    {
        get
        {
            if (target != null) return target.position;
#if UNITY_EDITOR || UNITY_STANDALONE
            return _camera.ScreenToWorldPoint(Input.mousePosition);
#elif UNITY_ANDROID || UNITY_IOS
        if (Input.touchCount > 0) return _camera.ScreenToWorldPoint(Input.GetTouch(0).position);
        else return Vector3.zero;
#endif
        }
    }

    private bool hasInput
    {
        get
        {
            if (target != null) return true;
#if UNITY_EDITOR || UNITY_STANDALONE
            return Input.GetMouseButton(0);
#elif UNITY_ANDROID || UNITY_IOS
        return Input.touchCount > 0;
#endif
        }
    }
    private static bool releaseInput
    {
        get
        {
#if UNITY_EDITOR || UNITY_STANDALONE
            return Input.GetMouseButtonUp(0);
#elif UNITY_ANDROID || UNITY_IOS
            return Input.touchCount == 0;
#endif
        }
    }
}