Cataracts

Japanese: 白内障

What kind of disease is it?

●Main symptoms and progression Cataracts are a disease in which the crystalline lens, which acts like a camera lens when we see things, becomes cloudy. The clouding begins in parts of the crystalline lens, and eventually covers the entire crystalline lens. Symptoms vary depending on which part is clouded, and sometimes there are no symptoms at all. You may feel glare in bright places, or things may look whitish and hazy overall. When the center of the crystalline lens becomes cloudy, your eyesight decreases.

●Causes of the disease and how symptoms developThere are many causes, but the most common is senile cataracts caused by aging.Although the severity varies, this disease affects most elderly people, so if you are over 60, you should have regular eye examinations as a preventative measure.
Other types of cataracts include those that are present at birth (congenital cataracts), traumatic cataracts caused by eye injury, and cataracts caused by diabetes or atopic dermatitis.

●Characteristics of the disease Senile cataracts are the most common, with 60-80% of people in their 60s experiencing some symptoms. Approximately 1.2 million surgeries to remove the cloudy lens and replace it with an artificial intraocular lens are performed annually, and of these, approximately 95% of patients recover to 0.5 or better.

EBM checks on common treatments and care

[Treatment and care] In the early stages of cataracts, progression can be slowed with eye drops. [Rating] ☆☆
[Evaluation Points] There are several clinical studies that show that eye drops can slow the progression of cataracts, but none of them can be considered to be reliable, and their effectiveness cannot be said to have been fully confirmed. New, reliable clinical studies will be needed to confirm their effectiveness. Before using these products, you should receive an explanation from an ophthalmologist. (1)-(5)

[Treatment and care] Identify the underlying disease [Rating] ☆☆☆☆
[Evaluation points] If you start to worry about a decline in your eyesight, you should undergo an examination to check for any underlying illnesses. Diabetes and atopic dermatitis may be the cause. Reliable clinical research has confirmed that the progression of cataracts can be prevented by treating the disease itself that is causing cataracts. Diabetes is particularly prone to cataracts, and it is more likely to develop in people under the age of 60. Blood sugar control is necessary to prevent this. (6)-(8)

[Treatment and care] If you are diagnosed with cataracts, you should undergo regular checkups to monitor the progression. [Rating] ☆☆☆
[Evaluation Points] Clinical studies have confirmed that checking the progression of cataracts through regular examinations is effective in determining the timing of surgery and other necessary measures. Smoking and diabetes are risk factors for cataracts. (6)-(8)

[Treatment and care] Surgery to implant an artificial lens (intraocular lens) [Rating] ☆☆☆
[Evaluation points] Once a lens becomes cloudy, it will not return to its original state. If vision deteriorates to the point that it interferes with daily life, surgery to implant an artificial lens is necessary to restore vision. The effectiveness of surgery to implant an artificial lens has been confirmed in several clinical studies. (6)(10)-(14)

[Treatment and care] Surgery should be carefully considered if you have heart disease, high blood pressure, or other optic nerve disease. [Rating] ☆☆☆
[Evaluation Points] Clinical studies have confirmed that people with diabetes or cardiovascular disease who undergo cataract surgery have a higher mortality rate after surgery. (6)(9)

[Treatment and care] After surgery, necessary glasses will be made and used. [Evaluation] ☆☆
[Evaluation points] When undergoing surgery to implant an artificial lens, the lenses in the eyes are replaced, so the glasses you have been using may no longer fit. For this reason, the opinions and experiences of experts support having new glasses made.

[Treatment and care] Use of vitamin preparations for prevention [Evaluation] ★→
[Evaluation Points] Vitamin C, vitamin E, and beta-carotene have been used as preventive drugs for cataracts, and have been supported by the experience and opinions of experts. However, in 2003, a guideline was issued stating that they could not be actively recommended due to the lack of reliable clinical research. (6)

Checking commonly used drugs with EBM

Eye drops to slow the progression of early cataracts [Drug name] Catalin/Karyuni (Pirenoxine) (1)-(3)
[Rating] ☆☆
[Drug name] Tathione (Glutathione) (4)(5)
[Rating] ☆☆
[Evaluation points] There are clinical studies that show that both drugs can slow the progression of cataracts, but none of the studies are very reliable, so conclusive results cannot be expected. These eye drops are not widely used in Europe and the United States.

Overall, the most reliable treatment currently available <br /> Surgery is the only reliable treatment The only reliable treatment for cataracts is surgical removal of the cloudy lens and insertion of an artificial intraocular lens.
Although several eye drops may theoretically improve or prevent cataracts, there are no reliable clinical studies clearly showing their effectiveness.
If there are no side effects, it may be possible to try using eye drops until the cataract progresses and causes inconvenience in daily life, but based on the current research results, we cannot expect a definitive effect. Guidelines have been issued stating that the use of vitamin C, vitamin E, and beta-carotene, which have been used as preventative medications, is not recommended.

Surgery is risky for the elderly and those with heart disease. Many countries around the world, especially developed countries, are experiencing an aging population, and the proportion of people over the age of 80 who develop cataracts is very high.
As patients get older, they are more likely to suffer from high blood pressure, diabetes, and heart disease, and the risks of surgery also increase. After considering these risks, patients and doctors need to have a thorough discussion about whether or not to go ahead with surgery.

Be cautious about lifestyle changes after surgery. It has also been pointed out that patients may suddenly regain their vision after surgery and expand their range of activities, but may not have enough physical strength (heart and limb strength) to keep up with the increased activity, which could lead to heart disease or falls. However, research in the United States has statistically shown that cataract surgery reduces the risk of traffic accidents.
When developing cataracts in young people, it is necessary to identify the cause and then perform specific treatment for that cause.

(1)Kociecki J, Załecki K, Wasiewicz-Rager J, Pecold K.Evaluation of effectiveness of Catalin eyedrops in patients with presenile and senile cataract.KlinOczna. 2004;106(6):778-82. Poland.
(2)Polunin GS, Makarova IA, Bubnova IA.Efficacy of catalin eyed drops in age-related cataract agents. VestnOftalmol. 2010 Jan-Feb;126(1):36-9.
(3)Tadahiko Murata. A double-blind clinical study on the effect of Catalin eye drops on senile cataracts. Journal of the Japanese Society of Ophthalmology. 1980;31:1217-1222.
(4) Tobari I, Kirisawa N, Umajima Y, et al. Clinical efficacy of glutathione eye drops for early senile cataracts: A double-blind study. Journal of Clinical Ophthalmology. 1982;76:1779-1787.
(5) Kawahara, T. and Obase, M. Quantitative analysis of the long-term course of senile cataracts: Clinical efficacy of glutathione eye drops. Atarashii Ophthalmology. 1984;1:864-867.
(6) Study on the formulation of evidence-based cataract treatment guidelines (H13-21EBM-012). FY2001 General and Cooperative Research Report. 2002, March.
(7)West SK, Valmadrid CT. Epidemiology of risk factors for age-related cataract. Surv Ophthalmol. 1995; 39:323.
(8)Lindblad BE, Håkansson N, Philipson B, Wolk A. Metabolic syndrome components in relation to risk of cataract extraction: a prospective cohort study of women. Ophthalmology. 2008; 115:1687.
(9)Ninn-Pedersen K, Stenevi U. Cataract patients in a defined Swedish population 1986-90:Ⅶ Inpatient and outpatient standardized mortality ratios. Br J Ophthalmol. 1995;79:1115-1119.
(10)Superstein R, Boyaner D, Overbury O. Functional complations, visual acuity, spatial contract sensitivity, and glare disability in preoperative and postoperative cataract patitiets. J Cataract Refract Surg. 1999;25:557-581.
(11)Tobacmman JK, Zimmerman B, Lee P, et al. Visuel function imparirmants in relation to gender, age, and visual acuity in patients who undergo cataract surgery. Opthalmogy. 1998;105:1745-1750.
(12)Busbee BG, Brown MM, Brown GC, Sharma S. Incremental cost-effectiveness of initial cataract surgery. Ophthalmology. 2002; 109:606.
(13)Agarwal A, Kumar DA. Cost-effectiveness of cataract surgery. Curr Opin Ophthalmol. 2011; 22:15.
(14)Lansingh VC, Carter MJ, Martens M. Global cost-effectiveness of cataract surgery. Ophthalmology. 2007; 114:1670.

Source: "EBM: A book that explains correct treatment" Information about the book "EBM: A book that explains correct treatment"

Japanese:

どんな病気でしょうか?

●おもな症状と経過
　白内障(はくないしょう)は、ものを見るときにカメラのレンズのような役目を果たしている水晶体が白く濁(にご)ってくる病気です。濁りは水晶体を部分的に侵しはじめ、やがて水晶体全体を覆(おお)います。濁りの部分によって自覚症状はさまざまで、ときにはまったく自覚症状がない場合もあります。明るいところでまぶしさを感じたり、全体に白っぽくものがかすんで見えたりします。水晶体の中央が濁ってくると視力が低下します。

●病気の原因や症状がおこってくるしくみ
　多くの原因がありますが、もっとも多いのが加齢による老年性白内障です。程度の差はあってもお年寄りのほとんどにおこる病気であるため、60歳を過ぎたら予防的な意味からも定期的な目の検査が必要です。
　そのほか、生まれつきの白内障（先天性白内障）、目のけがによっておこる外傷性白内障、糖尿病やアトピー性皮膚炎に伴っておこる白内障などがあります。

●病気の特徴
　老年性白内障がもっとも多く、60歳代の人の60～80パーセントになんらかの症状がみられます。濁った水晶体を取り除いて人工の眼内レンズを入れる手術は年間約120万件行われ、そのうちの約95パーセントの人は視力が0.5以上に回復しています。

よく行われている治療とケアをEBMでチェック

［治療とケア］初期の白内障であれば、点眼薬によって進行を抑える
［評価］☆☆
［評価のポイント］　点眼薬が白内障の進行を抑えることを示す臨床研究はいくつかありますが、どれも信頼性の高い研究とはいえず、十分に有効性が確認されているとはいえません。効果を確認するには信頼性の高い新たな臨床研究が必要でしょう。使用にあたっては眼科専門医の説明を受けるべきでしょう。(1)～(5)

［治療とケア］原因となっている病気を確認する
［評価］☆☆☆☆
［評価のポイント］　視力の低下が気になりはじめたら検査を行い、原因となっている病気がないか確認します。糖尿病やアトピー性皮膚炎が原因となっている可能性もあります。白内障を引きおこしている病気そのものを治療することで白内障の進行を予防できることは、信頼性の高い臨床研究によって確認されています。とくに糖尿病は白内障になりやすく、60歳以下で発症しやすくなっています。その予防には血糖コントロールを行う必要があります。(6)～(8)

［治療とケア］白内障と診断されたら、進行度を把握するために定期的に検査を受ける
［評価］☆☆☆
［評価のポイント］　定期的な検査で白内障の進行度をチェックすることは、手術の時期など必要な処置を見極めるのに有効であることが、臨床研究で確認されています。喫煙や糖尿病は白内障の危険因子となります。(6)～(8)

［治療とケア］人工水晶体（眼内レンズ）を埋め込む手術を行う
［評価］☆☆☆
［評価のポイント］　一度白く濁った水晶体は元に戻ることはありません。日常生活に支障をきたすほど視力が低下してきたら、それを回復するには人工の水晶体を埋め込む手術が必要です。人工水晶体を埋め込む手術の効果はいくつかの臨床研究で確認されています。(6)(10)～(14)

［治療とケア］心疾患や高血圧などがある場合や、ほかに視神経の病気がある場合、手術は慎重に検討する
［評価］☆☆☆
［評価のポイント］　白内障手術を受けた人のなかで、糖尿病や心臓血管病がある人は手術における死亡率が高いということが臨床研究によって確認されています。(6)(9)

［治療とケア］手術後には、必要な眼鏡をつくり、使用する
［評価］☆☆
［評価のポイント］　人工水晶体を埋め込む手術を行うと、目のレンズを入れ替えるわけですから、それまで使っていた眼鏡も合わなくなることがあります。そのため新しくつくり直すことが専門家の意見や経験から支持されています。

［治療とケア］予防のためにビタミン製剤を用いる
［評価］★→
［評価のポイント］　これまで白内障の予防薬としてビタミンC、ビタミンE、ベータカロチンが用いられることがあり、専門家の経験や意見から支持されてきました。しかし2003年、信頼性の高い臨床研究がないことから積極的には推奨できないとするガイドラインが示されました。(6)

よく使われている薬をEBMでチェック

初期の白内障の進行を抑えるための点眼薬
［薬名］カタリン／カリーユニ（ピレノキシン）(1)～(3)
［評価］☆☆
［薬名］タチオン（グルタチオン）(4)(5)
［評価］☆☆
［評価のポイント］　いずれの薬も白内障の進行を抑えることを示す臨床研究がありますが、どの研究も信頼性の高いものとはいえず、決定的な効果は期待できません。これらの点眼薬は欧米ではあまり使用されていません。

総合的に見て現在もっとも確かな治療法
手術が唯一の確実な治療法
　白内障の唯一の確実な治療は、混濁(こんだく)した水晶体の手術的摘出と人工の眼内レンズの挿入です。
　理論的に白内障を改善ないし予防する可能性のある点眼薬はいくつかありますが、明確に有効性を示した信頼性の高い臨床研究はありません。
　副作用さえなければ、白内障が高度になって日常生活に不便が生じるまでの間、点眼薬を使ってみてもよいと思いますが、現在までの研究成果をみる限りは決定的な効果は期待できません。予防的に用いられていたビタミンC、ビタミンE、ベータカロチンについて、使用は推奨できないとの指針が発表されています。

お年寄りや心疾患のある場合は手術に危険性が
　世界の多くの国々、とくに先進諸国では高齢化が進み、80歳以上の人では、白内障を発症する人の割合が非常に高くなっています。
　高齢になれば、高血圧や糖尿病、心疾患を合併する可能性も高くなり、手術時の危険性も高まります。そうしたリスクを検討したうえで手術に踏み切るかどうかを、患者さんと医師の間でよく話し合う必要があります。

手術後の生活の変化にも慎重な対応を
　また、手術後突然視力が回復して活動範囲が広がり、それに見合うだけの体力（心臓や手足の筋力）がないために心臓病や転倒をおこすなどの可能性も指摘されています。しかし、アメリカの研究では、白内障の手術により交通事故の可能性は減ることが統計学的に示されています。
　若年者での白内障は、その原因を明確にし、原因ごとに特有の治療が必要となります。

(1)Kociecki J, Załecki K, Wasiewicz-Rager J, Pecold K.Evaluation of effectiveness of Catalin eyedrops in patients with presenile and senile cataract.KlinOczna. 2004;106(6):778-82. Polish.
(2)Polunin GS, Makarova IA, Bubnova IA.Efficacy of catalin eyed drops in age-related cataract agents. VestnOftalmol. 2010 Jan-Feb;126(1):36-9.
(3)村田忠彦. 老人性白内障に対するカタリン点眼薬の効果に対する二重盲検法による臨床的研究. 日本眼科紀要. 1980;31:1217-1222.
(4)戸張幾生, 桐沢長徳, 馬嶋慶直, 他. 初期老人性白内障に対するグルタチオン点眼薬の臨床効果―二重盲検試験による検討―. 眼科臨床医報. 1982;76:1779-1787.
(5)河原哲夫, 尾羽沢大. 老人性白内障における長期的経過の定量的解析―グルタチオン点眼薬の臨床効果. あたらしい眼科. 1984;1:864-867.
(6)科学的根拠（evidense）に基づく白内障診療ガイドラインの策定に関する研究(H13-21EBM-012). 平成13年度総括・分担研究報告書. 2002, 3.
(7)West SK, Valmadrid CT. Epidemiology of risk factors for age-related cataract. Surv Ophthalmol. 1995; 39:323.
(8)Lindblad BE, Håkansson N, Philipson B, Wolk A. Metabolic syndrome components in relation to risk of cataract extraction: a prospective cohort study of women. Ophthalmology. 2008; 115:1687.
(9)Ninn-Pedersen K, Stenevi U. Cataract patients in a defined Swedish population 1986-90:Ⅶ Inpatient and outpatient standardised mortality ratios. Br J Ophthalmol. 1995;79:1115-1119.
(10)Superstein R, Boyaner D, Overbury O. Functional complations, visual acuity, spatial contract sensitivity, and glare disability in preoperative and postoperative cataract patitiets. J Cataract Refract Surg. 1999;25:557-581.
(11)Tobacmman JK, Zimmerman B, Lee P, et al. Visuel function imparirmants in relation to genter, age, and visual acuity in patients who undergo cataract surgery. Opthalmogy. 1998;105:1745-1750.
(12)Busbee BG, Brown MM, Brown GC, Sharma S. Incremental cost-effectiveness of initial cataract surgery. Ophthalmology. 2002; 109:606.
(13)Agarwal A, Kumar DA. Cost-effectiveness of cataract surgery. Curr Opin Ophthalmol. 2011; 22:15.
(14)Lansingh VC, Carter MJ, Martens M. Global cost-effectiveness of cataract surgery. Ophthalmology. 2007; 114:1670.