ποΈ Cataracts in Dogs and Cats β A 2025 Vetβs Guide to Diagnosis, Surgery & Long-Term Care
By Dr Duncan Houston, BVSc
π What Is a Cataract?
A cataract is an opacity or clouding in the lens of the eye that interferes with light passing through and reduces vision. Cataracts may affect a portion or the entire lens. In advanced cases, they cause full blindness. π§¬
π¬ Anatomy of the Lens
- π Located just inside the pupil
- π Suspended by fibers called zonules
- π― Focuses images onto the retina like a camera lens
- π§΄ Enclosed in a capsuleβdisruption can trigger immune inflammation
β οΈ Cataract vs. Nuclear Sclerosis
Older pets often develop nuclear sclerosisβa normal, age-related cloudiness from fiber compaction in the lens. Unlike cataracts, nuclear sclerosis does not cause blindness. Your vet can distinguish between them during an eye exam. π§ββοΈ
πΆ Cataracts in Diabetic Dogs
One of the most common causes of cataracts in dogs is diabetes mellitus. When blood glucose rises, excess sugar in the eye fluid is converted into sorbitol, drawing in water and clouding the lens. This can lead to rapid blindness, often within weeks. π§
π± Do Diabetic Cats Get Cataracts?
No. Cats have alternative sugar metabolism pathways and do not typically develop diabetic cataracts. πΊ
β οΈ Why Cataracts Are a Problem
- π§± Vision loss or blindness (partial or complete)
- π Lens luxation β the lens slips and blocks fluid drainage
- β‘ Glaucoma β increased eye pressure due to fluid backup
- π₯ Uveitis β inflammation from dissolving cataracts
π Diagnosing Cataracts
- ποΈ Eye exam and visual inspection
- π¦ Look for blockage of the tapetum (reflective layer at the back of the eye)
- π§ͺ ERG (electroretinogram) and ultrasound before surgery
π§ͺ Cataract Classifications
- Young: <10% visual impact
- Early Immature: 10β50%
- Late Immature: 51β99%
- Mature: 100% visual blockage
- Hypermature: Lens begins dissolvingβcan cause inflammation
π Can Eye Drops Dissolve Cataracts?
β οΈ No. Products claiming to dissolve cataracts do not work. N-acetylcarnosine drops may be antioxidants, but they do not reverse cataracts. Delaying surgery while using these drops may worsen the outcome. β
π₯ When Is Surgery Needed?
Surgery is considered if:
- ποΈ Cataracts significantly impair vision
- π₯ Inflammation is under control
- πΆ Pet is in good health and cooperative with post-op care
Pets with one functioning eye may not need surgery unless the other eye causes discomfort. π―
π§ Cataract Surgery Options
1. π οΈ Lens Extraction
- Larger incision
- More post-op inflammation
- Used in older or dense lenses
2. π‘ Phacoemulsification (Preferred)
- π₯ Ultrasonic tool liquefies the lens
- π§Ή Vacuum tool removes debris
- π Smaller incision, faster healing
After either procedure, an artificial lens implant is usually placed to improve visual clarity. π§Ώ
π Pre-Surgery Evaluation
- π§ͺ ERG test to check for retinal function
- π Ultrasound to check for detachment or other eye diseases
- π©Ί Blood tests and diabetes regulation
π‘οΈ Aftercare and Home Management
- π©Ή Elizabethan collar for 3 weeks
- π§ Cortisone eye drops for several months
- π Pupil-dilating drops
- πΎ Switch to a harness to reduce pressure on the head
- π Follow-up eye exams as scheduled
β οΈ Possible Complications
- π₯ Persistent uveitis
- π«οΈ Capsule opacity (may require further surgery)
- π©Έ Bleeding (can result from post-op stress or barking)
- π Glaucoma (especially with long surgeries or dissolving cataracts)
π Success Rates
95% of pets regain vision immediately after surgery; 80% maintain long-term visual success. ποΈβ
ποΈ What If the Cataract Isnβt Treated?
- π€ Vision loss is not painful
- π Some dogs adapt well; others become anxious
- π₯ Inflammation must be treated to avoid pain and further damage
π² Ask A Vet for Eye Surgery Support
Not sure if your pet needs cataract surgery? Want help managing blindness at home? Connect with the Ask A Vet App or visit AskAVet.com for expert guidance. πΆπ±
β Summary: Cataracts in Dogs and Cats
- ποΈ Cataracts block light and cause vision loss
- π Diabetic dogs are especially at risk
- 𧬠Not all lens cloudiness is a cataract (nuclear sclerosis is harmless)
- π οΈ Surgery is effective if the eye is healthy
- β οΈ Surgery is invasive and requires commitment
π¬ Final Words from Dr Duncan Houston
Cataracts are more than just cloudy eyesβthey can mean blindness, inflammation, or even glaucoma. But with early detection, accurate diagnosis, and the right care, your dog or cat has a great chance at comfort and restored vision. πΎπ
Reach out through the Ask A Vet App or at AskAVet.com for help navigating surgery, home care, or managing blindness. Weβre here for every step. π©ΊπΆ
This article is general veterinary education and does not diagnose or treat an individual animal. Always confirm medication names, doses and interactions with the veterinarian who knows your pet.
If your animal is struggling to breathe, collapsed, bleeding heavily, seizing, or has eaten something toxic, contact your vet or the nearest emergency clinic now.
Animal Poisons Helpline (AU) 1300 869 738 Β· Animal Poisons Helpline (NZ) 0800 869 738 Β· ASPCA Animal Poison Control (US) (888) 426-4435
More from Ask A Vet
For everyday pet care, one scan or tap of the smart pet ID tag opens your pet's free profile on any phone, no app needed; the GPS pet tracker logs live location and activity trends; and the Ask A Vet app keeps your pet's records and routines together.
Hanging QR & NFC Pet ID TagView ID TagThe ASK A VETβ’ Smart ID Tag is a QR scan or NFC tap on any phone, no app needed, with a free profile you can update anytime.
GPS Pet Tracker for Dogs and CatsView trackerThe ASK A VETβ’ Tracker logs live location and activity trends, so a change in routine never goes unnoticed.
- Talk to a Vet Online: The Ask A Vet AppExplore the app
Ask questions, speak with vets, and keep your pet's records and routines together with Ask A Vet.

Ask A Vet articles are written by Dr Duncan Houston BVSc, a practising veterinarian, unless another author is named in the byline.




