DETERMINATION OF APPEAL PANEL	
	
CITATION:	State of New South Wales (Northern NSW Local Health District) v Twomey [2024] NSWPICMP 716	
		
APPELLANT:	State of New South Wales (Northern NSW Local Health District)	
		
RESPONDENT:	Paul Michael Twomey	
		
Appeal Panel		
		
MEMBER:	Carolyn Rimmer	
		
MEDICAL ASSESSOR:	Kerrie Meades	
		
MEDICAL ASSESSOR:	Ian Wechsler	
		
DATE OF DECISION:	15 October 2024	
		
CATCHWORDS: 	wORKERS cOMPENSATION - Workplace Injury Management and Workers Compensation Act 1998; assessment of 23% whole person impairment of the visual system; no deduction pursuant to section 323 for pre-existing condition; Medical Appeal Panel (Panel) satisfied that Medical Assessor failed to adequately comment on medical opinions and provide adequate reasons in considering whether a deduction should be made pursuant to section 323; Panel reviewed the evidence and made a deduction of one tenth for pre-existing retinal detachment; Held – Medical Assessment Certificate revoked.	

BACKGROUND TO THE APPLICATION TO APPEAL
1.	On 12 July 2024 the State of New South Wales (Northern NSW Local Health District) (the appellant) lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Michael Steiner (Medical Assessor), who issued Medical Assessment Certificate (MAC) on 18 June 2024.
2.	The appellant relies on the following grounds of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (the 1998 Act): 
•	the assessment was made on the basis of incorrect criteria, and
•	the MAC contains a demonstrable error.
3.	The delegate is satisfied that, on the face of the application, at least one ground of appeal has been made out in the MAC of the Medical Assessor. The Appeal Panel has conducted a review of the original medical assessment but limited to the ground(s) of appeal on which the appeal is made. 
4.	Rule 128 of the Personal Injury Commission Rules 2021 (the PIC Rules) and Procedural Direction PIC7 - Appeals, reviews, reconsiderations and correction of obvious errors in medical disputes set out the practice and procedure in relation to the medical appeal process under s 328 of the 1998 Act. An Appeal Panel determines its own procedures in accordance with r 128(1) of the PIC Rules.
5.	The assessment of permanent impairment is conducted in accordance with the SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4th ed 1 March 2021 (the Guidelines) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 4th ed (AMA 4). 
RELEVANT FACTUAL BACKGROUND
6.	Paul Michael Twomey (Mr Twomey/the respondent) suffered an injury to his right eye during his employment with the appellant on 14 May 2021. 
7.	Mr Twomey lodged an Application to Resolve a Dispute (ARD) in the Personal Injury Commission (Commission) on 29 April 2024 in which he claimed an amount of $52,950 in respect of 19% whole person impairment (WPI) of the visual system as a result of the injury on 15 May 2021. 
8.	The Medical Assessor examined Mr Twomey on 13 June 2024 and assessed 23% WPI of the visual system. No deduction was made pursuant to s 323 of the 1998 Act and therefore the total WPI, as a result of the injury on 15 May 2021, was 23%. 
PRELIMINARY REVIEW
9.	The Appeal Panel conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Procedural Direction PIC7.
10.	As a result of that preliminary review, the Appeal Panel determined that it was unnecessary for Mr Twomey to undergo a further medical examination because there was sufficient information upon which to make a determination.
EVIDENCE
Documentary evidence
11.	The Appeal Panel has before it all the documents that were sent to the Medical Assessor for the original medical assessment and has taken them into account in making this determination. 
Medical Assessment Certificate
12.	The parts of the medical certificate given by the Medical Assessor that are relevant to the appeal are set out, where relevant, in the body of this decision. 
SUBMISSIONS 
13.	Both parties made written submissions. They are not repeated in full but have been considered by the Appeal Panel. 
14.	The appellant’s submissions include the following:
(a)	Ground 1 – the Medical Assessor erred and applied incorrect criteria by failing to consider, adequately or at all, the relevant medical history when deciding not to make a deduction under s 323 of the 1998 Act for impairment due to previous injury or pre-existing condition or abnormality. 
(b)	In taking the history detailed in the MAC and then determining not to make a deduction under s 323, the Medical Assessor fell into error by not taking into account relevant factual and medical factors which were present prior to and following the subject injury, and failing to record and report the full extent of the past medical history, including the discussions between the doctors regarding causation of the retinal detachment and whether it was acute (due to trauma) or spontaneous.
(c)	Mr Twomey did report suffering from a right pterygium to the Medical Assessor. and this was noted in the MAC. 
(d)	The medical history was readily available from reviewing the material enclosed to the referral; yet there is no consideration by the Medical Assessor (adequately or at all) regarding this history, which includes: 
(i)	a “floater” and worsening vision reported in the immediate period prior to the subject injury; 
(ii)	a pre-existing pterygium which “appeared more inflamed” and was considered to have been aggravated by the incident at work; 
(iii)	a retinal detachment occurring spontaneously in the left eye at around the same time, even though it was not injured in the incident at work; 
(iv)	discussions between the treating doctors about the likelihood of the retinal detachment in the right eye being spontaneous and not trauma related [i.e., related to the work incident], and 
(v)	conclusions by both medical experts engaged by the parties in this matter that Mr Twomey likely suffered a predisposition to retinal problems that were aggravated by the subject injury.
(e)	There was no requirement on Medical Assessor to discuss each and every piece of evidence in the MAC, and any lack of reference should not be taken as evidence the Medical Assessor did not have regard to this material. However, the content of the evidence attached to the referral to the Medical Assessor revealed prior significant matters regarding Mr Twomey’s medical history and emergence of the subject injury, almost all of which did not appear in the MAC or, where reference was made, was not adequately considered. 
(f)	The material referred to above was readily available to the Medical Assessor, yet was not discussed or adequately discussed, and any discussion lacked the relevant analysis or contextualization. The Medical Assessor did not address the co-occurring problems in the left eye and suggestion of a predisposition to the retinal problems. The Medical Assessor did not refer to the reports of Dr Martin at all, even when asked to provide “comments regarding the other medical opinions and findings submitted by the parties and, where applicable, the reasons why my opinion differs”.
(g)	The failure to address these prior factors and failure to consider the differing conclusions reached by both Dr Bors and Dr Martin amounts to a demonstrable error.
(h)	In the context of the above factors which were not taken into account (either adequately or at all), the failure to make a deduction under s 323 was made on the basis of an incorrect medical history and was an error on the part of the Medical Assessor.
(i)	There was a lack of any adequate consideration or analysis of significant medical factors, such that these submissions form more than mere disagreement about the assessment of impairment. The factors outlined above support the conclusion that Mr Twomey was likely to be more susceptible to the occurrence of the injury or to an aggravation injury, and in turn, more likely to suffer greater impairment as a result. The appellant therefore submits the Medical Assessor failed to adequately address the real and proper contribution of this history, insofar as it was available to him to do so, to the impairment that resulted from the work injury.
(j)	It follows the Medical Assessor made a demonstrable error by failing to consider, adequately or at all, the prior history detailed above, and therefore made a decision to not make a deduction under s 323 without regard to the actual consequences of the prior history and therefore made by way of speculation. 
(k)	Ground 2 – the Medical Assessor erred and applied incorrect criteria by failing to provide any or any adequate justification for his decision to not make a deduction under s 323 of the 1998 Act for impairment due to previous injury or pre-existing condition or abnormality.
(l)	In light of the prior medical history detailed above and conclusions of the medical experts engaged by the parties that Mr Twomey suffered a predisposition to retinal tear and detachment, the reasons provided by the Medical Assessor in determining not to make a deduction under s 323 were significantly inadequate, and this amounts to a demonstrable error.
(m)	In the context of the medical evidence, and where there were alternative conclusions open to the Medical Assessor on the deduction, which had been considered and (differently) applied by Dr Bors and Dr Martin, the Medical Assessor was obliged to give reasons for reaching his determination and to address the difference in his opinion.
(n)	The Medical Assessor would have been aware that a greater deduction than the statutory assumption under s 323 had already been made by Dr Martin. Dr Bors, who did appear to be aware of the prior history and concluded Mr Twomey, had a predisposition to retinal detachment similarly provided an alternative conclusion.
(o)	While the Medical Assessor was not required to follow the opinion of any of the doctors qualified by the parties, the presence of such contrasting assessments as to the extent of the deductible proportion presented him with an obligation to engage in consideration of those alternative conclusions available to him, and to provide reasons for arriving at the conclusion that no deduction was warranted.
(p)	While there is no requirement for the reasons provided by the Medical Assessor to be extensive or detailed, the reasons which were provided were not only insufficient in terms of addressing the task required of him in assessing any deductible proportion but contradicted the available medical evidence.
(q)	The Medical Assessor did not explain why he came to the view that the prior medical history did not warrant a deduction. He did not engage in any such consideration of the relevant matters contained in the medical evidence, nor why his opinion differed from both Dr Bors (in terms of a predisposition) and Dr Martin (in respect of predisposition and the s 323 deduction). This amounted to inadequate reasons and constituted a demonstrable error.
(r)	For the reasons outlined above, the conclusions reached by the Medical Assessor in determining no previous injury or pre-existing condition or abnormality was present, and in turn, deciding no deduction under s 323 was warranted, have been insufficiently explained, and he made a determination which is inconsistent with the available evidence. 
(s)	The MAC should be revoked and a new MAC issued by the Medical Appeal Panel which contains its assessment of permanent impairment as a result of the injury on 14 May 2021, and applies a deduction under s 323 which would be more consistent with the injury being an aggravation injury, and consistent with the available evidence.
15.	Mr Twomey’s submissions include the following:
(a)	the grounds of appeal do not establish any error on the part of the Medical Assessor or that the MAC contains any demonstrable error. The grounds of appeal do not establish the Medical Assessor utilised incorrect criteria when assessing permanent impairment.
(b)	The reasons provided by the Medical Assessor for his assessment of WPI were logical, cogent, well reasoned and adequate and do not give rise to error. 
(c)	Ground 1 – relevant medical history: the medical history referred to in the appellant's submissions, refers to matters that do not form part of the relevant medical history of the work injury. 
(d)	Dr Clark expressed the view that the retinal detachment of the right eye was a non-trauma related, spontaneous condition. The Medical Assessor provides a different opinion, specifically, that the injury Mr Twomey sustained during the course of his employment was the cause of the retinal detachment. In his report dated 18 October 2022, Dr Bors also opined that the work injury caused the retinal detachment.
(e)	The Medical Assessor comments on Mr Twomey’s vision prior to the injury, opining "He had glasses prescribed previously. These were quite weak and only for driving". The appellant refers to the opinion of Dr Bors, regarding pre-existing weakness to Mr Twomey’s right retina. Despite identifying this in his report, Dr Bors was still of the opinion that a deduction under s 323 of the 1998 Act was not required.
(f)	The MAC dated 18 June 2024 contains the relevant medical history and based on this history, the Medical Assessor, agreed with Dr Bors and also found that no deduction under s 323 of the 1998 Act was required.
(g)	There is no evidence to suggest that the Medical Assessor did not undertake a clinical evaluation of the impairment of the respondent that was in accordance with the Guidelines.
(h)	The assessment of permanent impairment is a matter for each doctor based on their clinical experience and assessment of the evidence before them.
(i)	The decision of Dr Bors and the Medical Assessor not to make a deduction under s 323 of the 1998 Act where Dr Martin was of the opposite opinion, is nothing more than a difference of opinion.
(j)	It cannot be said that the decision of the Medical Assessor not to make a deduction under s 323 of the 1998 Act was glaringly improbable in the circumstances amounting to a demonstrable error warranting intervention on the basis that two out of the three independent medical experts that examined Mr Twomey came to the same conclusion.
(k)	On this basis the appeal must fail as its submissions are, in effect, a complaint that relates to merely a difference of opinion which is not a ground of appeal (see Ferguson v State of NSW & Ors [2017] NSWSC8879 among others).
(l)	Ground 2 – justification of the Medical Assessor’s decision. Mr Twomey repeats his submissions above.
(m)	If the lack of reasons given by the Medical Assessor is found to be grounds for appeal, it does not follow that a deduction under s 323 of the 1998 Act should therefore have been made.
(n)	The decision of the Medical Assessor not to make a deduction under s 323 of the 1998 Act represents nothing more than a difference of opinion to that of Dr Martin.
(o)	The appellant failed to show any demonstrable error on the part of the Medical Assessor. There has been no demonstrable error or application of incorrect criteria. Rather the basis for appeal is based on a subjective dissatisfaction with the assessment of the Medical Assessor. The appellant's submission must therefore fail as it is, in effect, a complaint that relates to merely a difference of opinion which is not a ground of appeal (see Ferguson v State of NSW & Ors [2017] NSWSC887).
(p)	The MAC dated 18 June 2024 should be confirmed.
(q)	Alternatively, if an Appeal Panel determines a deduction should be made it should made under s 323 (2) of the 1998 Act on the basis it would be difficult or costly to determine.
FINDINGS AND REASONS 
16.	The procedures on appeal are contained in s 328 of the 1998 Act. The appeal is to be by way of review of the original medical assessment but the review is limited to the grounds of appeal on which the appeal is made. 
17.	In Campbelltown City Council v Vegan [2006] NSWCA 284 the Court of Appeal held that the Appeal Panel is obliged to give reasons. Where there are disputes of fact it may be necessary to refer to evidence or other material on which findings are based, but the extent to which this is necessary will vary from case to case. Where more than one conclusion is open, it will be necessary to explain why one conclusion is preferred. On the other hand, the reasons need not be extensive or provide a detailed explanation of the criteria applied by the medical professionals in reaching a professional judgement.
Ground 1 – failure to consider relevant medical history when deciding whether to make a deduction under s 323
18.	The appellant submits that the Medical Assessor erred and applied incorrect criteria by failing to consider, adequately or at all, the relevant medical history when deciding not to make a deduction under s 323 of the 1998 Act for impairment due to previous injury or pre-existing condition or abnormality. 
19.	The Appeal Panel reviewed the evidence in this matter.
20.	The Medical Assessor under “history relating to the injury” wrote:
“He was making a patient’s bed and had folded the sheet into a V. He flicked the sheet back and it hit him in his right eye. He immediately developed a subconjunctival haemorrhage and the eye was very sore. He was given Maxidex eye drops by a Registered Nurse. The following day he noticed floaters and flashes and five days later he noticed a shadow like a veil across his right vision. He already had an appointment to see his Ophthalmologist in three weeks for his right pterygium and so waited the three weeks before seeing Dr Roswell(sic). Dr Roswell(sic) diagnosed a retinal detachment and referred him to Dr Augustus Clarke. Dr Clarke operated on the detachment and all in all Mr Twomey has had four operations by Dr Clarke. One to operate on the retinal detachment. One to remove the lens which had become cataractous and replace it with an implant. The retina then re-detached so the third operation was insertion of silicone oil and the fourth operation was removal of the silicone oil several months later. At some stage Dr Clarke also did right a Yag Laser Capsulotomy and early on he also did laser to pre-detachment lesions in the left retina. Mr Twomey last saw Dr Clarke almost a year ago and he is due to see him on an annual basis”.
21.	Under “Details of any previous or subsequent accidents, injuries or condition” the Medical Assessor wrote:
“He had had glasses prescribed previously. These were quite weak and only for driving. He has had no accidents or other conditions”.
22.	Under “Findings on physical examination”, the Medical Assessor wrote:
“His uncorrected vision is 6/60 on the right and 6/9 on the left. The vision on the right could not be improved and on the left he has mild astigmatism and corrects to 6/6 and with an appropriate reading addition could be made to read N5 size print. There was a large pterygium on the right. There was a well centered intraocular lens and the posterior capsule had had a Yag Laser Capsulotomy. His intraocular pressure was raised on the right at 28mmHg and normal on the left at 17mmHg. Examination of the fundi showed that there is significant cupping of the right disc with a cup:disc ratio of 0.8. The left disc was normal with a cup:disc ratio of 0.4.
On the right there were only signs of retinal detachment surgery involving the retinal mid periphery and on the left there were laser scars in the upper temporal retinal mid periphery”.
23.	Under “Details and dates of special investigations”, the Medical Assessor wrote:
“An OCT was performed and is appended to this report and shows very significant epiretinal membrane with distortion of the macular region on the right. It also shows increased cupping of the right optic disc. Visual field testing was also performed and shows enlargement of the blind spot and a supero-temporal scotoma”.
24.	Under “Summary” the Medical Assessor wrote: 
“• 	summary of injuries and diagnoses: 
He has had a blunt injury to the right eye resulting in a retinal detachment which has been treated and the vitrectomy that was required to treat the retinal detachment has caused him to develop a cataract in the right eye which is extremely common following vitrectomy surgery and he then re-detached and has developed very severe distortion of the macular
region in the right eye which would appear to be intractable.
• 	consistency of presentation
While it is unusual for a cotton bed sheet to cause such a significant injury, it was flicked back and there is no doubt that it was the cause of his retinal detachment. Mr Twomey showed me the photograph of the eye soon after the accident, when he had quite a nasty subconjunctival haemorrhage so obviously the sheet hit the eye with significant force so all in all the history is consistent”.
25.	Under “Evaluation of Permanent Impairment” the Medical Assessor answered the following questions: 
“e. 	Is any proportion of loss of efficient use or impairment or whole person impairment, due to a previous injury, pre-existing condition or abnormality? No.
f. 	If so, please indicate which body part/system is affected by the previous injury, preexisting condition or abnormality. 
Not appliable”.
26.	The Medical Assessor assessed 23% WPI of the visual system. His comments regarding the other medical opinions were as follows: “I have awarded a higher whole person impairment than Dr Frank Bors as Mr Twomey’s vision was worse when I saw him than when he saw Dr Bors.”
27.	The Medical Assessor at Part 11 of the MAC wrote: 
“a. 	In my opinion the worker suffers from the following relevant previous injuries, pre-existing conditions or abnormalities:
(i) 	Nil.”
28.	The appellant submits that in taking the history detailed in the MAC and in turn, determining not to make a deduction under s 323, the Medical Assessor fell into error by not taking into account relevant factual and medical factors which were present prior to and following the subject injury, and failing to record and report the full extent of the past medical history, including the discussions between the doctors regarding causation of the retinal detachment and whether it was acute (due to trauma) or spontaneous.
29.	In his statement dated 24 April 2024, Mr Twomey wrote:
“3. 	At around 2:30am on 15 May 2021 I was making one of the hospital beds. While folding the sheet back from the top corner of the bed, the corner of the sheet flicked up and hit me directly in the right eye.
4. 	My eye hurt and became extremely bloodshot. Photos were taken to evidence this 3 hours after the incident. I had initially assumed that my pterygium was hit and flared up.
5. 	I went to the emergency department of Casino Hospital and told them what had happened. One of the doctors took a look at my eye and diagnosed a sub-conjunctival haemorrhage…
6. 	After I finished work, on the evening of 15 May 2021, started experiencing ‘flashes’ and ‘floaters’ in my right eye.
7. 	I had never experienced any side effects of the pterygium except that there was a spot in my eye visible when I looked in the mirror.
8. 	A day or two later I started noticing a light in the left corner of my right eye when I had my eye closed. I could also see a small dark spot on the upper left quadrant when my eye was open.
9. 	On 30 April 2021, I went to see my GP Dr Witt…I was able to get in quickly because I had a pre-booked appointment to discuss the pterygium as I had thought it was getting bigger. There were no other issues at this time regarding the pterygium except its size.”
30.	In a referral dated 30 April 2021, Dr Brian Witt, general practitioner (GP), referred Mr Twomey to Dr Rodwell for ophthalmology treatment in respect of a “floater in his R eye and vision on his R side being a bit more blurry… Paul has a pterygium over the medial aspect of his R eye that has been a bit more active… [he] finds his vision is not as good when hunting”. 
31.	Dr Steven Rodwell, treating ophthalmologist, in a report dated 27 May 2021 noted that Mr Twomey had a right temporal retinal detachment which involved about half of the fundus and also had a “limited peripheral retinal detachment superotemporally in the left eye”. 
32.	Dr Augustino Clark, treating ophthalmologist, in a report dated 28 May 2021, noted that Mr Twomey had a “Retinal detachment (Macula Off) RE – onset 28/05/2021” and a “Retinal tear (ST – Barrier laser) LE – onset 28/05/2021”. 
33.	Dr Clark, in a report dated 30 August 2021, under “Treatment/Plan” noted that “Paul had a rhegmatigenous retinal detachment in the right eye. He also has a horseshoe retinal tear in his left eye. These are spontaneous conditions and not trauma related”. 
34.	In a referral to Dr Matthew Green dated 22 November 2021, Dr Witt described the injury on 14 May 2021, and wrote: 
“Paul had a preexisting pterygium that appeared more inflamed. Paul states he started noticing a light in the left corner of his right eye and a small dark spot medially on the upper left quadrant of his right eye 1-2 days after the injury. He may have noted a large floater at this same time Paul noted a vertical blackness starting to traverse across his R eye from left to right starting on the 23rd of May at 6.05 am nasally from medial aspect of visual field and traversing to his cental (sic) vision. Paul became aware of vision impairment now involving his R lateral visual field and central vision”.
35.	In a report dated 18 October 2022, Dr Bors, consultant ophthalmologist, under “Prior history” noted:
“He was known to have had a right pterygium for years… He said that prior eye checks by OPSM or SpecSavers had shown no problems”. 
Under “Prognosis” Dr Bors wrote: “As an unrelated matter the right pterygium or the left cataract may worsen needing surgery.” 
36.	Under “Causation”, Dr Bors wrote:
“I note that Dr Clark on 30th August 2021 said ‘these are spontaneous conditions and not trauma related’.
I note that Dr Weaver on 3rd December 2021 said ‘the timing may suggest a causal effect and direct eye trauma is a risk factor for retinal detachments’.
It is evident that there was most probably a pre existent retinal weakness and predisposition to retinal tear and detachment based on the presence of a spontaneous left retinal tear which had no trauma and the close temporal association between injury and detachment in the right eye. 
I therefore consider that the injury precipitated a retinal detachment in an eye predisposed by an inherent spontaneous weakness”. 
37.	Dr Frank Martin, consultant ophthalmologist, in a report dated 17 May 2023, commented on diagnosis and causation in respect of the right eye condition: 
“In my opinion, Mr Twomey had a predisposition for retinal degeneration. At the time, when he consulted his General Practitioner, Dr Witt on 30 April 2021, he complained of a floater in his right eye and vision on the right side being a bit more blurred. Uncorrected visual acuity in the right eye at this visit was 6/9. The alleged injury occurred on 15 May 2021 and when he attended Ophthalmologist, Dr Stephen Rodwell, he was found to have a right retinal detached which Dr Rodwell felt had been present for a period of time as there were fibrotic changes. Dr Rodwell also found him to have degeneration in the left retina with a detachment.
In my opinion, the alleged injury on 15 May 2021 aggravated a prior retinal problem in the right eye”. 
38.	 Dr Martin then wrote:
“In my opinion, Mr Twomey had a predisposition to retinal problems in the right eye that were aggravated by the alleged injury on 15 May 2021. In respect to causation, in my opinion, there was a predisposition to retinal problems that were aggravated by the alleged injury on 15 May 202, leading to a retinal detachment.” 
39.	Dr Martin made a deduction for pre-existing condition noting: 
“In my opinion, I consider a proportion of the permanent impairment to be due to pre-existing retinal degeneration. Mr Twomey had complained of a floater in his right vision and blurring of his right vision on 30 April 2021, prior to his injury on 15 May 2021. In my opinion, a deduction of 35% should be applied to the whole person impairment”. 
40.	Dr Martin commented on Dr Bors’ assessment noting: 
“…Dr Bors agrees that most probably a pre-existent retinal weakness and predisposition to retinal tear and detachment was present. He has not recorded that a floater in the right eye was present prior to the injury and documented by Dr Witt. Dr Bors should have considered a deduction for a pre-existing condition.” 
41.	Dr Martin also asserted the calculation of WPI by Dr Bors did not comply with the Guidelines, and in his opinion, loss of field of vision should not be included as “an accurate visual field is not possible”
42.	The Appeal Panel agree with the appellant that the Medical Assessor made no reference to the report of Dr Martin and, in particular, the deduction made pursuant to s 323 of the 1998 Act for a pre-existing condition, namely, pre-existing retinal degeneration. 
43.	The Appeal Panel noted that although the Medical Assessor reported that Mr Twomey already had an appointment to see his ophthalmologist for his right pterygium before the injury on 15 May 2021, the Medical Assessor did not refer to the “floater in his R eye and vision on his R side being a bit more blurry” as described by Dr Witt in the referral to Dr Rodwell dated 30 April 2021. 
44.	The Appeal Panel noted that Dr Clark, in a report dated 30 August 2021, reported that Mr Twomey had a “rhegmatigenous retinal detachment in the right eye. He also has a horseshoe retinal tear in his left eye. These are spontaneous conditions and not trauma related”. Dr Rodwell, in a report dated 27 May 2021, noted that Mr Twomey had a right temporal retinal detachment which involved about half of the fundus and also had a “limited peripheral retinal detachment superotemporally in the left eye”.
45.	The Appeal Panel agrees with the parties that there is no requirement on the Medical Assessor to discuss each and every piece of evidence in the MAC, and any lack of reference should not be taken as the Medical Assessor not having had regard to the material. 
46.	However, at Part 10 c of the MAC, the Medical Assessor wrote: 
“My brief comments regarding the other medical opinions and findings submitted by the parties and, where applicable, the reasons why my opinion differs
I have awarded a higher whole person impairment than Dr Frank Bors as Mr Twomey’s vision was worse when I saw him than when he saw Dr Bors”.
47.	The Medical Assessor made no reference at all to the report of Dr Martin, despite an obvious difference in opinion in respect of a s 323 deduction. 
48.	The Appeal Panel is satisfied that the Medical Assessor failed to adequately comment on medical opinions submitted by the parties and, in particular, on the opinion of Dr Martin. Further, the Medical Assessor failed to provide reasons as to why his opinion differs from that of Dr Martin. The failure to provide adequate reasons is a demonstrable error. 
49.	The Appeal Panel considers that the second ground of appeal is also made out. The Appeal Panel was satisfied that the Medical Assessor failed to provide adequate reasons in considering whether a deduction should be made pursuant to s 323 of the 1998 Act. 
Deduction pursuant to s 323
50.	Section 323 of the 1998 Act provides:
“(1) 	In assessing the degree of permanent impairment resulting from an injury, there is to be a deduction for any proportion of the impairment that is due to any previous injury (whether or not it is an injury for which compensation has been paid or is payable under Division 4 of Part 3 of the 1987 Act) or that is due to any pre-existing condition or abnormality.
(2) 	If the extent of a deduction under this section (or a part of it) will be difficult or costly to determine (because, for example, of the absence of medical evidence), it is to be assumed (for the purpose of avoiding disputation) that the deduction (or the relevant part of it) is 10% of the impairment, unless this assumption is at odds with the available evidence.
Note. So if the degree of permanent impairment is assessed as 30% and subsection (2) operates to require a 10% reduction in that impairment to be assumed, the degree of permanent impairment is reduced from 30% to 27% (a reduction of 10%).
(3) 	The reference in subsection (2) to medical evidence is a reference to medical evidence accepted or preferred by the medical assessor in connection with the medical assessment of the matter. 
(4) 	The WorkCover Guidelines may make provision for or with respect to the determination of the deduction required by this section”.
51.	The approach to be taken in assessing the s 323 deduction was considered by the Supreme Court in Cole v Wenaline Pty Limited [2010] NSWSC 78 (Cole). Schmidt J said: 
“29 	...The section is directed to a situation where there is a pre-existing injury, pre-existing condition or abnormality. For a deduction to be made from what has been assessed to have been the level of impairment which resulted from the later injury in question, a conclusion is required, on the evidence, that the pre- existing injury, pre-existing condition or abnormality caused or contributed to that impairment.
30 	Section 323 does not permit that assessment to be made on the basis of an assumption or hypothesis, that once a particular injury has occurred, it will always, ‘irrespective of outcome’, contribute to the impairment flowing from any subsequent injury. The assessment must have regard to the evidence as to the actual consequences of the earlier injury, pre-existing condition or abnormality. The extent that the later impairment was due to the earlier injury, pre-existing condition or abnormality must be determined. The only exception is that provided for in s 323(2), where the required deduction ‘will be difficult or costly to determine (because, for example, of the absence of medical evidence)’. In that case, an assumption is provided for, namely that the deduction ‘is 10% of the impairment'. Even then, that assumption is displaced, if it is at odds with the available evidence. 
31 	...That is a matter of fact to be assessed on the evidence led in each case”.
52.	At [38] of Cole, Schmidt said:
“38. 	What s 323 required, however, was that the evidence be considered, so that it could be determined, firstly, what the level of impairment after the second injury was. Secondly, whether a proportion of that impairment was due to the first injury. Thirdly, what that proportion was. Undoubtedly in undertaking this exercise, the medical members of an Appeal Panel must utilise their medical judgement, knowledge and experience. Nevertheless, all stages of the statutory exercise must be undertaken in the light of the evidence and without the making of assumptions not provided for by the section.”
53.	In Elcheikh v Diamond Formwork (NSW) Pty Ltd [2013] NSWSC 365 Schmidt J referred to her decision in Cole, stating:
“88. 	Section 323 requires that once the level of impairment which results from a work injury has been established, that a medical specialist must make 'a deduction for any proportion of the impairment that is due to any previous injury'. As discussed in Cole v Wenaline Pty Limited at [29] that requires a conclusion: ‘on the evidence, that the pre-existing injury, pre-existing condition or abnormality caused or contributed to that impairment'.”
54.	In Ryder v Sundance Bakehouse [2015] NSWSC 526 Campbell J considered the legislative and authoritative history of s 323. He said at [42]:
“In the present context the critical question is the causation question which, expressed by adapting the terms of the statute is whether a portion of the 15 per cent whole person impairment Ms Ryder suffered as a result of her work injury was due to a pre-existing condition or abnormality i.e. degenerative disc disease. The argument advanced on behalf of Ms Ryder is effectively that the proportion must be capable of assessment in accordance with the WorkCover Guides for s 323(1) to be satisfied. With respect this overlooks the requirement that the section must be read as a whole and in its legislative context. ...
43. I acknowledge that the express words of s 323(1) require that some definite part, even if it is difficult or costly to assess in precise terms, of the impairment has been caused by, in this case, a pre-existing condition. But the interpretation adopted by the Court of Appeal is that the section is engaged if the pre-existing condition, or previous injury where applicable, is a concurrent necessary condition, with the work injury, of the degree of permanent impairment.”
55.	Consistent with this line of authority, s 323(1) must be construed as requiring deduction from the assessment of the degree of permanent impairment of any proportion of the impairment that is due to “previous injury ... or ... pre-existing condition or abnormality”, whether or not the pre-existing condition or abnormality is symptomatic at the time of injury. 
56.	The Appeal Panel, having noted the observations made by Dr Witt in the referral to Dr Rodwell dated 30 April 2021, are satisfied that Mr Twomey had a pre-existing condition in both eyes, namely, a small retinal detachment, probably involving a retinal hole, and also a pterygium in the right eye. 
57.	Mr Twomey has seen Dr Witt on 30 April 2021 and then sustained the work injury to the right eye on 15 May 2021. The Appeal Panel considered that the injury on 15 May 2021 caused a subconjunctival haemorrhage in the right eye which caused immediate symptoms including floaters and flashing lights. The injury to the right eye caused the existing retinal detachment to rapidly progress so that Mr Twomey lost vision in the right eye by 23 April 2021. By the time Mr Twomey saw Dr Rodwell on 27 April 2021, Mr Twomey had a right temporal retinal detachment which involved about half of the fundus, while his left eye had a limited peripheral retinal detachment superotemporally, which was quickly and effectively treated by barrier laser. 
58.	The Appeal Panel noted that the pterygium in the right eye reported by the GP, Dr Witt, on 30 April 2021 could have contributed to the change in 6/9 vision noted in that consultation. However, the Appeal Panel is satisfied that the pterygium did not cause any of the impairment later assessed by the Medical Assessor. 
59.	Having found that Mr Twomey had a pre-existing condition, namely a small retinal detachment, the question to be addressed is whether a proportion of the impairment assessed by the Medical Assessor is due to that pre-existing condition. The Appeal Panel was satisfied that if the work injury had not occurred, the pre-existing retinal detachment would not have rapidly progressed but would have stayed small (as it did in the left eye) and been easily treated (as the left eye retinal detachment was treated). 
60.	However, the Appeal Panel considers that the pre-existing retinal detachment has contributed to a small degree to the impairment assessed by the Medical Assessor. The deduction of 35% by Dr Martin, in our view, is excessive, and Dr Martin did not explain properly the actual consequences of the pre-existing condition and how he arrived at the deduction of 35%. 
61.	The Appeal Panel notes the time frame of retinal symptoms after the workplace injury on 15 May 2021. In Mr Twomey’s statement he said that he developed symptoms of flashing lights and floaters in the right eye on the day of the injury. These symptoms indicate retinal traction precipitated by the workplace injury. Mr Twomey said that two days later he experienced a light in the corner of the right eye and he could see a small dark spot in the upper left quadrant of the right eye. Mr Twomey then stated that on 23 May a curtain came over the right eye. This chronicle of retinal symptoms is typical of a rapidly progressive retinal detachment. It is the opinion of the Appeal Panel that Mr Twomey had preexisting bilateral early rhegmatogenous retinal detachments (retinal detachment arising from a retinal hole).
62.	The workplace injury on 15 May 2021 significantly contributed to the speed of progression of the right retinal detachment and caused a rapid separation of the two layers of the right retina to involve the right macula resulting in severe and permanent loss of right vision. The left eye was not injured and did not have this progression and was easily treatable as an outpatient. He had minor retinal laser to the left eye with no loss of left vision. The difference in the outcome of the two eyes is a reflection of the impact of the workplace injury on the right eye. It is the opinion of the Medical Panel that a 35% deduction is therefore not in keeping with the evidence 
63.	The Appeal Panel was satisfied that the deduction in this case is difficult to determine because of the absence of medical evidence concerning the extent of the pre-existing retinal detachment prior to the injury. Therefore, the Appeal Panel makes a deduction of 10% which is not at odds with the available evidence. It follows that 23% less 10% (2.3%) equals 20.7% which is rounded up to 21% WPI. 
64.	The Appeal Panel noted that the appellant submitted that a deduction pursuant to s 323 of the 1998 Act should be made in respect of a predisposition to retinal problems. The Appeal Panel rejects this submission. In Cullen v Woodbrae Holdings Pty Ltd [2015] NSWSC 1416, Beech-Jones J reiterated the need for evidence of an actual pre-existing condition rather than a predisposition or susceptibility, 
65.	The medical members of the Appeal Panel noted the Medical Assessor found that Mr Twomey’s intraocular pressure was raised on the right at 28mmHg and examination of the fundi showed that there is significant cupping of the right disc with a cup:disc ratio of 0.8. In addition, it appears that Mr Twomey has visual field defects. The Appeal Panel therefore strongly recommends that Mr Twomey arrange a review by his treating ophthalmologist as soon as possible for further management and investigation. 
66.	For these reasons, the Appeal Panel has determined that the MAC issued on18 June 2024 should be revoked, and a new MAC should be issued. The new certificate is attached to this statement of reasons.

WORKERS COMPENSATION DIVISION
APPEAL PANEL
MEDICAL ASSESSMENT CERTIFICATE
Injuries received after 1 January 2002

Matter number:	W3382/24	
Applicant:	Paul Michael Twomey	
Respondent:	State of New South Wales (Northern NSW Local Health District)	
This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act 1998.
The Appeal Panel revokes the Medical Assessment Certificate of Medical Assessor Dr Michael Steiner and issues this new Medical Assessment Certificate as to the matters set out in the Table below:
Table - whole person impairment (WPI) 
Body Part or system	Date of Injury	Chapter, page and paragraph number in NSW workers compensation guidelines 	Chapter, page, paragraph, figure and table numbers in AMA 4 Guides
	% WPI 	Proportion of permanent impairment due to pre-existing injury, abnormality or condition	Sub-total/s % WPI (after any deductions in column 6)	
1.Visual system 	14/05/2021		Paragraph 3 page 209 
Table 7
Table 6 	23%	1/10th
	21%	
Total % WPI (the Combined Table values of all sub-totals) 	21%