在單眼驗光之後需要進行雙眼調節平衡，方式有很多種，其中一種較特別的方式為HUMPHRISS IMMEDIATE CONTRAST (HIC)。概念是先霧視非檢查眼，接著在檢查眼之前輪流以+/-0.25DS鏡片比較清晰度。
此種方式的好處是兩眼皆處於開放狀態，有雙眼融像更接近真實視覺狀態，調節也能有較好控制。
當比較兩片鏡片時。會有三種可能的結果，+0.25DS比較清楚、-0.25DS比較清楚、兩者相同。
但不同教科書上對於步驟及終點卻有不同的描述，又因為最原始的版本無法獲得，所以我試著比較手上三本有比較完整步驟的教科書，看看不同作者的作法。
1. Clinical Procedures for Ocular Examination 4th
/NANCY B. CARLSON, DANIEL KURTZ
這本是大部分視光學校的屈光實驗教科書，書上對於終點是這麼描述的
- a. If the patient reports that the -0.25 D sphere is clearer, add-0.25 D to the correction (or take away + 0.25 D) and continue step 5 until the two views appear equal.
- b. If the +0.25 is preferred, add a +0.25 to the correction and continue step 5.
- If on the next comparison the patient prefers the -0.25, add the -0.25 and proceed to step 6.
- c. If the two views appear equal, leave the correction as is and proceed to step 6
...終點為直到兩片鏡片看起來相同．而正或負清楚則加入相對應鏡片之後到反向出現．
2. OPTOMETRY : Science, Techniques and Clinical Management
/Mark Rosenfield, Nicola Logan
- lf the patient is not accommodating, then they should immediately respond that the target is clearer with the minus lens.
- lf the patient gives one of three responses , either that
- (1) the plus lens is clearer
- (2) that there is no difference between the two lenses or
- (3) that the minus lens is clearer, but it makes the letters smaller or blacker,
- then it can be assumed that the patient is accommodating.
- With any of these three answers, additional plus sphere should be added and the test repeated until the patient has no hesitation in responding that the-0.25 DS is preferred.
3. Clinical Procedures in Primary Eye Care
/David B. Elliott
- 6. If the patient immediately reports that the-0.25 DS is definitely clearer, repeat the demonstration of the lenses and ask if the-0.25 DS ‘is definitely clearer or just smaller and blacker’.
- Only add -0.25 DS if the patient immediately reports that the lens is definitely clearer.
- 8 .If the patient reports that the +0.25 DS is clearer or that there is no difference, add +0.25 DS to the refractive correction
- 10.Continue to compare the -0.25 DS and +0.25 DS until the +0.25 DS is immediately rejected.
