Optician India

The number of people you see with cataract will depend on the type of people who frequent your practice. I work in independent practice in a small town with 90% of my patients being above 60 years old and 9% less than 12 years old. The remainder are somewhere in between. I see a lot more cataract than an optometrist working in a city centre practice where there are typically more people of working age. My focus in this article will be people who have not previously had cataract and who have not previously had cataract extraction, who, when referred, will see a government funded ophthalmologist and have a monofocal intraocular lens implanted. Privately funded multifocal intraocular lens implantation will be the subject of a future article.

When I examine a person with cataract the main decision I have to make is: Does this person need referral for cataract extraction or does this person need to be monitored by me?. In order to make this decision I am guided by ‘Personal considerations’ and ‘Clinical Considerations’. Personal considerations flow from the history and symptoms and from the discussion that comes after the clinical considerations stage. Once I’ve thought about these considerations I along with the person can decide on the best management for them. Below I describe these considerations along with factors which need to be taken into account during the referral stage, if there is one.

Stages of managing people with age-related cataract:

1. Personal considerations from history and symptoms.
2. Clinical considerations from data gathering during refraction and ophthalmoscopy.
3. Personal considerations from discussion.
4. Referral considerations (when referral is appropriate).

The three types of cataract I encounter are nuclear sclerotic (around 90%), cortical (around 9%) and a hybrid of nuclear sclerotic and cortical (around 1%)

Personal considerations from history and symptoms

After discussing the weather (I work in the United Kingdom) my first question is whether the person has any problems or has noticed any changes in their eyes or vision since their last eye examination. People in the age-group where cataract is prevalent often respond with one or more of the following, in order of commonality; 

I can’t see text on the TV (either at all or as well as I used to).

Glare from car headlights at night time is worse now.

I have noticed a reduction in my far vision and my reading vision.

I have trouble with road signs a long way away.

My vision is generally less than it was last time and it’s gradually got worse.

If the person has been previously examined in the practice and there is a note in the clinical records that they have lens opacities/cataract I mention this to the person and they usually remember being told about this. I advise the person that I will check to see if the cataract has got worse since last time.

Clinical considerations from data gathering during refraction and ophthalmoscopy

My first clinical test is to measure distance visual acuity (with current glasses if any) with both eyes open and each eye in turn. When there is new cataract or previous cataract has progressed I often find one eye is 6/12 or worse. Sometimes, even though the person complains of symptoms typical of cataract I find that the visual acuity is 6/7.5 or better.

I often note that the near reading acuity with the eye that has reduced distance visual acuity is N5 at around 30-40 cm with a good light (more on lighting later). When distance visual acuity is reduced and the near reading acuity is in the normal range this tells me that the person has undergone a myopic shift and may benefit from more a minus refractive correction.

My first lens movement is to change the refractive correction by -0.50 monocularly. In my experience, 70% of people I examine under these clinical circumstances notice an increase in visual acuity with more minus. I then continue modifying the refractive correction (usually more minus) until I get the best corrected visual acuity for each eye. This is often an improvement from 6/18 to 6/9 or from 6/12 to 6/7.5. The benefit of more minus tells me that the person has progressive nuclear sclerosis in one or both eyes. The greater refractive index of the cataractous lens material (nuclear  sclerosis) means that light is bent more as it goes through the person’s natural lens and is focussed in front of the retina. Applying more minus to the refractive correction moves the focal point back to the fovea and visual acuity is increased.

In my experience people with cortical cataract often need more plus power to obtain their best corrected visual acuity. I have not found anything in the literature to explain the mechanism for this or even if it is a phenomenon but in my personal experience it seems to be a clinical thing.

Once I have the optimum refractive correction, I demonstrate the benefit of the new prescription by showing the person their monocular visual acuity with the new lens power and with the old lens power. ‘This is the level you managed with your current glasses and this is the level you can manage with the new lenses’. They often notice a significant improvement. I emphasis the point that I can improve their vision despite the cataract worsening.

I also demonstrate the importance of a reading lamp for ease of reading. I ask the person to read N5 (or appropriate print size) with my reading lamp shining light on the page of print I have asked them to read. As they read fluently I switch the lamp off. Typically the person’s reading falters or they stop reading altogether. I then switch the lamp back on and fluent reading resumes. This is a very powerful demonstration particular if there is another family member in the consulting room. They can easily hear and see the difference between fluent reading with the lamp on and the faltering reading when I turn the lamp off. I ask if the person has a reading lamp at home and the response is usually ‘No, but I’m going to get one now, as I can see how it helps my reading’.

I then look at the natural lens using my direct ophthalmoscope. I note the extent of the cataract and it’s density in terms of the darkness of the shadow it casts when it blocks light reflected off the person’s retina that then passes through my ophthalmoscope and on to my retina. I also review the best corrected visual acuity I have found and rate the cataract in each eye on a scale of 1 to 10 with 10 being a cataract that needs an operation and 1 being hardly anything at all. I explain my rating scale to the patient, give them my score and note it in the clinical records for use next time. I know there are more formal cataract grading scales but my system suits me and my situation. I also let the person know what the score typically would be for a person in their age group. If a 75 year old scores 3 they often take some comfort in knowing that most 75 year olds have a score of at least 6.

I briefly explain that it is UV from the sun over their life time that has caused the cataract. I show the person a diagram on my wall of a cross section through an eye and indicate where the cataract is and how it has caused their visual problems. Many have heard of a cataract and know it’s  something which reduces vision in older age but nothing more; and why should they? I add that their everyday glasses (if they wear them for far vision when outside) will protect their eyes from UV but if holidaying in a very sunny area then prescription sunglasses or photochromics will offer even more protection and slow cataract progression.

It would be useful to measure contrast threshold (demonstrating a reduction in contrast sensitivity) but I don’t have the necessary chart to measure this and very few clinicians (including ophthalmologists) show any interest in knowing what the person’s contrast threshold is. Every clinical decision is based on visual acuity and the person’s symptoms. This is a shame since it is well known that visual acuity (high contrast black on white) is a poor indicator of real world vision, much of which is shades of grey on shades of grey.

Personal considerations as part of discussions

I tell the person that yes the cataract has worsened but I’ve managed to improve their visual acuity so new glasses would help them in their everyday life and that I will monitor the cataract in 12 months’ time. Most people are happy that they will be able to see better and any surgery has been put off to another day.

Other times, I tell the person I haven’t managed to improve the visual acuity but that it’s not in the range where surgery would be conducted through the government funded National Health Service (NHS) even though they might be having some visual difficulties in their everyday life. Again, I agree to monitor in 12 months. Sometimes the person asks me what the visual acuity level needs to before being eligible for NHS surgery and I show them the 6/12 line on the Snellen chart. A good friend and colleague of mine Kalbinder Kang recently reminded me not to base my referral criteria solely on the person’s symptoms but to take into their visual acuity. He reminded me that surgery has its limitations and if the person has 6/9 or 6/7.5 pre-operatively, the post-operation best corrected visual acuity may not be as good as this.

Sometimes people whom I advise that it would be to their visual advantage to have a cataract extraction decline and these are some of the reasons: 'Sick of going to hospitals for other health problems', ‘Getting there and back’ and ‘Not being able to instil post-operation eye drops’. Some simply don’t want to go to a hospital and others don’t want ‘any one messing with my eyes’.

Some people are happy to know that they meet the driving vision requirements, moderate their night time driving and are happy to use the latest generation of photochromic lenses when driving. This helps with practice sustainability.

Some people ask me how long it takes for cataract to progress to a point where surgery would be necessary and I respond between 5 and 10 years. I sense that some people then think about how long they have left to live and conclude they will have passed before they need cataract surgery.

Others are keen to be referred for extraction. Those who know people who have had a successful extraction are particularly bolstered. Sometimes people know others who have had an unsuccessful extraction and are reluctant to be referred.

The NHS is clear in its referral guidance for cataract surgery. Prior to referral the person must agree to the referral and they must want the surgery. No one will be happy if at the pre-op appointment with an ophthalmologist the person declines surgery.

Referral considerations

When the person and I agree that referral to be considered for cataract extraction is the correct line of management I explain what will be involved in the referral and surgery processes. In my area it was possible to refer a person to a named ophthalmologist. There was a local ophthalmologist who had all the attributes I wanted for my patients. Good personal skills and excellent surgical skills. My patients always came back and told me how well they could see and how happy they were with her. This surgeon also sent me the relevant post-surgery information. Things have changed and I am now obliged to refer my patients into a NHS hub where administrators decide which is the closet surgical unit to the patient and which has the shortest wating time and then refer the patient to that unit.

Once we have decided on referral I have a second thought about the possibility of ocular co-morbidity and make sure I have checked for any other conditions which might delay, complicate or prevent surgery, such as blepharitis, corneal endothelial or lenticular pigment and age-related macular degeneration. Missing ocular co-morbidity which is then picked up by the receiving ophthalmologist can damage patient confidence in your clinical skills and lead to a waste of time. Consider dilation when the view of the macula is obstructed by the cataract. No one likes to be surprised by the presence of age-related macular degeneration.

I explain that there will be two and maybe three visits to the surgical unit. A pre-op, when important eye measurements are made. This involves pupil dilation so the person shouldn’t drive themselves to the appointment. Then another visit on the day of surgery, again no driving. And then a third visit at the unit for a post-op examination. The post-op examination is sometimes delegated by the ophthalmologist back to me and then I then send them my findings.

I have a poster on my wall of a cross section through the eye and use this to explain what cataract extraction surgery will involve. A very small incision at the edge of the cornea, a probe inserted to break up and remove the cataract and another probe inserted to implant the intraocular lens and allow it to fold open. All done under local anaesthetic and taking between 5 and 15 minutes.

I explain that people I know who have had cataract extraction notice improved real world vison, such as TV, reading, recognising people’s faces, driving and reading. After extraction and implantation, some people don’t need distance glasses although this is not guaranteed. This is a welcome bonus for people, although most don’t expect independence from distance glasses and don’t mind wearing them because some have had distance glasses for the previous 50 to 60 years.

I also mention improved contrast threshold will allow better grey on grey discrimination, there will be less glare in the sun and less night time glare when driving and improved appreciation of colours. Post-extraction people often mention to me how bright colours are: ‘Everything is so much more colourful’.

I mention the possibility of posterior capsular opacification, what to look out for and what to do if the symptoms typical of posterior opacification are noticed. This is often, but not always, mentioned by the operating ophthalmologist. Posterior capsular opacification will be the topic of a future article.

People often ask when they can have the second eye done. Then the process I have described above starts again.