DISEASES OF CONJUNCTIVA KERATITIS AND CORNEAL OPACITIES

R. BISIGNANI · 2025 · Case ID: 25014144

DENIED

Summary

The Veteran, an Army Veteran who served from July 1968 to July 1970, appeals the denial of service connection for bilateral eye disabilities (excluding dry eye syndrome) and obstructive sleep apnea. The Veteran claimed these conditions were directly related to in-service herbicide exposure and secondarily to service-connected diabetes and hypertension. The Board acknowledged the Veteran's service in Vietnam and conceded herbicide exposure. However, multiple VA examinations, including one in September 2024, consistently opined that the Veteran's bilateral eye conditions (glaucoma, cataracts, dermatochalasis) and obstructive sleep apnea were less likely than not related to service, caused by aging, heredity, or overweightness, and not linked to herbicide exposure, diabetes, or hypertension. The Board found the VA opinions more probative than a private physician's opinion, which was deemed speculative. The Board also noted that the Veteran's service treatment records were negative for complaints related to these conditions. Consequently, service connection for bilateral eye disabilities (other than dry eye syndrome) and obstructive sleep apnea was denied on both direct and secondary bases.

Rationale

Service treatment records negative for complaints/treatment of bilateral eye disability.; VA examiner opined less likely than not related to service, citing aging/heredity/lack of risk factors.; Private physician opinion deemed speculative.; Weight of evidence against secondary connection to diabetes/hypertension.

Service Branch

ARMY

Special Benefit

NO SPECIAL BENEFIT

Docket No.

19-19 057A

Full Decision Text

Citation Nr: 25014144
Decision Date: 11/19/25 Archive Date: 11/19/25

DOCKET NO. 19-19 057A
DATE: November 19, 2025

ORDER

Entitlement to service connection for a bilateral eye disability, other than dry eye syndrome, is denied.

Entitlement to service connection for obstructive sleep apnea is denied.

FINDINGS OF FACT

1. A bilateral eye disability, other than dry eye syndrome disability, is not related to service, and is not caused or aggravated by a service-connected disability.

2. An obstructive sleep apnea disability is not related to service, and is not caused or aggravated by a service-connected disability.

CONCLUSIONS OF LAW

1. Service connection for a bilateral eye disability, other than dry eye syndrome disability, to include as secondary to a service-connected disability, is not warranted. 38 U.S.C. §§ 1110, 1131 (2012) 38 C.F.R. §§ 3.303, 3.304, 3.310, (2021).

2. Service connection for an obstructive sleep apnea disability, to include as secondary to a service-connected disability, is not warranted. 38 U.S.C. §§ 1110, 1131 (2012) 38 C.F.R. §§ 3.303, 3.304, 3.310 (2021).

REASONS AND BASES FOR FINDINGS AND CONCLUSIONS

The Veteran served on active duty in the U.S. Army from July 1968 to July 1970.

This appeal comes to the Board of Veterans' Appeals (Board) from a September 2018 rating decision by a Department of Veterans Affairs (VA) Regional Office (RO).

In July 2023 and May 2024, the Board remanded the Veteran's claims for service connection for additional development.

The Board notes that the previous remands characterized the Veteran's claim as service connection for bilateral eye disabilities. As noted in the May 2024 Board remand, the Veteran has extensive diagnoses associated with his bilateral eyes. Notably, in a November 2024 rating decision, the RO granted service connection for bilateral dry eye syndrome at an initial noncompensable evaluation, effective April 3, 2018. As a result of this grant and the additional eye diagnoses, the Board has characterized the claimed bilateral eye disability as entitlement to service connection for a bilateral eye disability, other than dry eye syndrome.

Service Connection

Laws and Regulations

Service connection will be granted if the evidence demonstrates that a current disability resulted from an injury or disease incurred in or aggravated by active military service. 38 U.S.C. §§ 1110, 1131; 38 C.F.R. § 3.303(a).

To establish a right to compensation for a present disability, a Veteran must show: "(1) the existence of a present disability; (2) in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the present disability and the disease or injury incurred or aggravated during service." Davidson v. Shinseki, 581 F.3d 1313, 1315-16 (Fed. Cir. 2009); Shedden v. Principi, 381 F.3d 1163, 1167 (Fed. Cir. 2004).

In relevant part, 38 U.S.C. § 1154(a) requires that the VA give "due consideration" to "all pertinent medical and lay evidence" in evaluating a claim to disability or death benefits. Lay evidence can be competent and sufficient to establish a diagnosis of a condition when (1) a layperson is competent to identify the medical condition, (2) the layperson is reporting a contemporaneous medical diagnosis, or (3) lay testimony describing symptoms at the time supports a later diagnosis by a medical professional." Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed.Cir.2007). In fact, competent medical evidence is not necessarily required when the determinative issue involves either medical etiology or a medical diagnosis. Id. at 1376-77; see also Buchanan v. Nicholson, 451 F.3d 1331, 1337 (Fed. Cir. 2006); Davidson v. Shinseki, 581 F.3d 1313 (Fed. Cir. 2009).

Once evidence is determined to be competent, the Board must determine whether such evidence is also credible. See Layno, supra (distinguishing between competency ("a legal concept determining whether testimony may be heard and considered") and credibility ("a factual determination going to the
(Fed.Cir.2007). In fact, competent medical evidence is not necessarily required when the determinative issue involves either medical etiology or a medical diagnosis. Id. at 1376-77; see also Buchanan v. Nicholson, 451 F.3d 1331, 1337 (Fed. Cir. 2006); Davidson v. Shinseki, 581 F.3d 1313 (Fed. Cir. 2009).

When there is an approximate balance of positive and negative evidence regarding any issue material to the determination of a matter, the VA shall give the benefit of the doubt to the claimant. 38 U.S.C. § 5107(b).

Under 38 C.F.R. § 3.310(a), service connection may be granted for disability that is proximately due to or the result of a service- connected disease or injury. Such permits a grant of service connection not only for disability caused by a service-connected disability, but for the degree of disability resulting from aggravation to a nonservice- connected disability by a service- connected disability. Id. See also Allen v. Brown, 7 Vet. App. 439, 448 (1995); 38 C.F.R. § 3.310(b).

In order to prevail on the issue of entitlement to secondary service connection, there must be (1) evidence of a current disability; (2) evidence of a service-connected disability; and (3) nexus evidence establishing a connection between the service-connected disability and the current disability. See Wallin v. West, 11 Vet. App. 509, 512 (1998).

Veterans who, during active service, served in the Republic of Vietnam during the period beginning on January 9, 1962, and ending on May 7, 1975, shall be presumed to have been exposed to an herbicide agent, unless there is affirmative evidence of non-exposure. 38 U.S.C. §§ 1116; 38 C.F.R. § 3.307.

"Service in the Republic of Vietnam" includes service in the waters offshore and service in other locations if the conditions of service involved duty or visitation in the Republic of Vietnam. 38 C.F.R. §§ 3.307(a) (6) (iii), 3.313(a).

A veteran who served in certain locations between January 9, 1962, and May 7, 1975, shall be presumed to have been exposed during such service to an herbicide agent, unless there is affirmative evidence to establish that the veteran was not exposed to any such agent during that service. 38 U.S.C. § 1116 (f); 38 C.F.R. §§ 3.307 (a)(6)(iii), 3.307(d). Honoring Our Promise to Address Comprehensive Toxics (PACT) Act, Pub. L. 117-168 (August 10, 2022). In such circumstances, service connection may be granted on a presumptive basis for the diseases listed in 38 C.F.R. § 3.309(e). 38 U.S.C. § 1116(a)(1); 38 C.F.R. § 3.307 (a)(6)(ii). When a claimed disability is not included as presumptive disorder, a veteran may nevertheless establish service connection based evidence of actual direct causation. See Combee v. Brown, 34 F.3d 1039 (Fed. Cir. 1994); Brock v. Brown, 10 Vet. App. 155 (1997) (applying principle to Agent Orange exposure).

The diseases presumed to be associated with herbicide exposure include: chloracne or other acneform diseases consistent with chloracne, type 2 diabetes (also known as type II diabetes or adult-onset diabetes), Hodgkin's disease, ischemic heart disease (including, but not limited to, acute, subacute, and old myocardial infarction; atherosclerotic cardiovascular disease including coronary artery disease (including coronary spasm) and coronary bypass surgery; and stable, unstable and Prinzmetal's angina), all chronic B-cell leukemias (including, but not limited to, hairy-cell leukemia and chronic lymphocytic leukemia), multiple myeloma, non-Hodgkin's lymphoma, Parkinson's disease, acute and subacute peripheral neuropathy, porphyria cutane
acne or other acneform diseases consistent with chloracne, type 2 diabetes (also known as type II diabetes or adult-onset diabetes), Hodgkin's disease, ischemic heart disease (including, but not limited to, acute, subacute, and old myocardial infarction; atherosclerotic cardiovascular disease including coronary artery disease (including coronary spasm) and coronary bypass surgery; and stable, unstable and Prinzmetal's angina), all chronic B-cell leukemias (including, but not limited to, hairy-cell leukemia and chronic lymphocytic leukemia), multiple myeloma, non-Hodgkin's lymphoma, Parkinson's disease, acute and subacute peripheral neuropathy, porphyria cutanea tarda, prostate cancer, respiratory cancers (cancer of the lung, bronchus, larynx, or trachea), and soft-tissue sarcomas (other than osteosarcoma, chondrosarcoma, Kaposi's sarcoma, or mesothelioma). 38 C.F.R. § 3.309 (e). In addition, the National Defense Authorization Act for Fiscal Year 2021, P. L. 116-283, § 6501, 134 Stat. 3388 (Jan. 1, 2021) added bladder cancer to the list of conditions presumptively associated with exposure to herbicide agents, and the Honoring our PACT Act of 2022, Pub. L. 117-168 (August 10, 2022) recently added hypertension and monoclonal gammopathy of undetermined significance. 38 U.S.C. § 1116 (a)(2)(J).

VA's Secretary has determined that there is no positive association between exposure to herbicides and any other condition for which he has not specifically determined a presumption of service connection is warranted. See Diseases Not Associated with Exposure to Certain Herbicide Agents, 75 Fed. Reg. 81,332 (Dec. 27, 2010); see also Determinations Concerning Illnesses Discussed in National Academy of Sciences Report: Veterans and Agent Orange, 77 Fed. Reg. 47,924 (Aug. 10, 2012).

For the purposes of § 3.307, the term herbicide agent means a chemical in an herbicide used in support of the United States and allied military operations in the certain locations during the Vietnam era. 38 C.F.R. § 3.307 (a)(6)(i); Honoring our PACT Act of 2022 (August 10, 2022). Agent Orange is generally considered an herbicide agent and will be so considered in this decision.

The Board additionally notes that eye disabilities and obstructive sleep apnea are not listed as diseases that the VA has associated with herbicide exposure. Nevertheless, the regulations also provide that service connection may be granted for any disease diagnosed after discharge, when all evidence, including that pertinent to service, establishes that the disability was incurred in service. 38 C.F.R. §§ 3.303 (d), 3.309(e); see also Combee v. Brown, 34 F.3d 1039 (Fed. Cir. 1994). In other words, a presumption of service connection provided by law is not the sole method for showing causation in establishing a claim for service connection for disability due to herbicide exposure. See Stefl v. Nicholson, 21 Vet. App. 120 (2007) (holding that the availability of presumptive service connection for some conditions based on exposure to Agent Orange does not preclude direct service connection for other conditions based on exposure to Agent Orange).

Bilateral Eyes

The Veteran asserts that his bilateral eye disabilities are directly related to his in-service herbicide agent exposure and are secondary to his service-connected diabetes and hypertension.

The Veteran is service connected for type II diabetes and hypertension. Further, VA has conceded the Veteran's in-service herbicide agent exposure.

The Veteran underwent a VA examination in August 2018. The examiner found that the Veteran's glaucoma was less likely than not "proximately due to or the result of" the Veteran's diabetes mellitus type II. The examiner relied on the absence of evidence of glaucoma in service treatment records and also opined that the medical literature did not show an association between diabetes mellitus type II and open angle glaucoma, and there was questionable reliability of net analysis of the association between diabetes and open angle glaucoma.

The examiner also noted that the Veteran's reduction in visual acuity was due to his refractive error and senile nuclear sclerosis which were congenital and developmental in origin. The examiner stated that bilateral pinguecula "are not caused or the result of diabetes mellitus" because they "occur due to actinic changes affecting
likely than not "proximately due to or the result of" the Veteran's diabetes mellitus type II. The examiner relied on the absence of evidence of glaucoma in service treatment records and also opined that the medical literature did not show an association between diabetes mellitus type II and open angle glaucoma, and there was questionable reliability of net analysis of the association between diabetes and open angle glaucoma.

The examiner also noted that the Veteran's reduction in visual acuity was due to his refractive error and senile nuclear sclerosis which were congenital and developmental in origin. The examiner stated that bilateral pinguecula "are not caused or the result of diabetes mellitus" because they "occur due to actinic changes affecting the subepithelial collagen and elastoid fiber of the conjunctiva causing degeneration to th[e] fibers." The examiner opined that vitreous floaters are not caused or the result of diabetes mellitus as they were common and develop "as the vitreous gel inside the eye ages[, and] strands of protein become visible within it."

The Veteran underwent a VA examination in December 2023. The examiner opined that the Veteran's claimed condition was "less likely than not... incurred in or caused by the claimed in-service injury, event, or illness." The examiner stated that open angle glaucoma was "less likely than not produced by service-connected agent orange exposure" and copied the August 2018 examiner's opinion. The examiner opined that nuclear cataracts was "less likely than not produced by the claimed in-service injury, event, or illness" because it was age-related in the Veteran's case. The examiner explained that the clouding of the eye was the result of aging, in which key proteins in the eye broke down and distorted once clear parts of the eye. The examiner also opined that dermatochalasis was "less likely than not produced by the claimed in-service, event or illness" because it was age-related in the Veteran's case.

In March 2024, a VA clinician provided an opinion for the Veteran's right eye, stating that the Veteran's right eye disability was less likely than not incurred in or caused by the claimed in-service injury, event, or illness. The clinician opined that right eye glaucoma, nuclear cataract, and dry eye syndrome were less likely than not "incurred in or caused by the claimed in-service injury, event or illness" because all of the conditions were diagnosed "decades post active duty." The clinician opined that right eye nuclear cataract was due to natural aging, which is the most common cause. The clinician stated that glaucoma was both hereditary and due to natural aging.

In a separate March 2024 opinion, the clinician provided the same opinion and rationale for the left eye.

In another March 2024 opinion, the same VA clinician opined that the Veteran's claimed condition was less likely than not "caused by the indicated toxic exposure risk activity(ies), after considering the total potential exposure through all applicable military deployments of the Veteran and the synergistic, combined effect of all toxic exposure risk activities of the Veteran." The provider listed relevant evidence in the rationale portion of the opinion, including the VA TERA memo showing herbicide agent exposure. The clinician stated that the records she reviewed did not indicate any risk factors outside of military service. The clinician opined that the right eye condition was less likely than not caused by the indicated TERA after considering the total potential exposure through all applicable military deployments of the Veteran and the synergistic, combined effect of all toxic exposure risk activities of the Veteran. As rationale, the clinician stated that there was no medical or scientific evidence providing "any indication of a relationship between the development of the condition(s) at issue and the TERA." Furthermore, she stated that risk factors outside of military service, such as hereditary, hormonal, and aging, "far outweigh[ed] the factors identified in the TERA." The clinician explained that nuclear cataracts was due to natural aging; glaucoma was due to hereditary and natural aging; and dry eye syndrome was due to hormonal changes and aging.

For the left eye, the clinician opined that the claimed condition was less likely than not caused by the indicated toxic exposure risk activity, after considering the total potential exposure through all applicable military deployments of the Veteran and the synergistic, combined effect of all toxic exposure risk activities of the Veteran. The clinician again listed pertinent records and reviewed the TERA memo. She stated that risk factors outside of military service were natural aging and hereditary. The clinician opined that the Veteran's left eye disability was less likely than not caused by the indicated TERA after considering the total potential exposure through all applicable military deployments and the synergistic, combined effect of all toxic exposure risk activities of the Veteran. As rationale, the clinician indicated that there was no medical or scientific evidence providing "any indication of a relationship between the development of the condition(s) at issue and the TERA." She explained that risk factors outside of military service far outweighed the factors identified in the TERA. The clinician attributed left eye nuclear cataract to natural aging and glaucoma to hereditary and natural aging. The clinician stated that if left dry eye syndrome were due to service, the Veteran would be expected to have the onset of symptoms during service, which was not the case based on his service treatment records.

Per the May 2024 Board remand instructions, the Veteran underwent a VA examination in September 2024. The examiner indicated that the Veteran had diagnoses of bilateral open angle glaucoma, bilateral nuclear cataracts, bilateral dry eye syndrome and bilateral dermatochalasis. The examiner opined that it was less likely than not that the Veteran's bilateral eye disabilities, aside from dry eye syndrome, were incurred in or caused by the claimed in-service event, injury or illness. The examiner also opined that it was less likely than not that the Veteran's bilateral eye disabilities, aside from dry eye syndrome, were proximately due to, the result of, or aggravated by the Veteran's service-connected hypertension and diabetes disabilities. Finally, the examiner opined that the Veteran's bilateral eye disabilities, aside from dry eye syndrome, were less likely than not caused by the indicated toxic exposure risk activity(ies), after considering the total potential exposure through all applicable military deployments of the Veteran and the synergistic, combined effet of all toxic exposure risk activities of the Veteran.

The examiner noted that aside from bilateral dry eye syndrome, the Veteran had diagnoses of bilateral open angle glaucoma, bilateral nuclear cataracts, and bilateral dermatochalasis, all of which did not have a common risk factor for an in-service event, injury or illness. A known risk factor for cataracts was natural aging. The Veteran's glaucoma was likely caused by natural aging or heredity as the Veteran's record demonstrated that he was not diagnosed with glaucoma until many years after service. The Veteran's bilateral dermatochalasis was caused by the drooping of the upper eye lid and resulted from natural aging and less elasticity of the skin as a person ages.

Regarding secondary service connection, the examiner noted that the Veteran's bilateral open angle glaucoma, bilateral nuclear cataracts, and bilateral dermatochalasis, did not have common risk factors of hypertension or diabetes. The examiner also opined that it was less likely than not that the Veteran's bilateral eye disabilities were aggravated beyond their natural progression by the service-connected diabetes mellitus or hypertension as they were instead caused by the common risk factors.

When considering the pertinent evidence of record in light of the above-noted legal authority, the Board finds that service connection for a bilateral eye disability, other than dry eye syndrome, is not warranted.

As there are diagnoses of bilateral open angle glaucoma, bilateral nuclear cataracts, and bilateral dermatochalasis, the first element of service connection is satisfied. However, a veteran seeking disability benefits must establish not only the existence of a disability, but also an etiological connection between his military service and the disability. Boyer v. West, 210 F.3d 1351, 1353 (Fed. Cir. 2000); D'Amico v. West, 209 F.3d 1322, 1326 (Fed. Cir. 2000); Hibbard v. West, 13 Vet. App. 546, 548 (2000).

The Board notes that the Veteran's service treatment records are negative for complaints or treatments for a bilateral eye disability.

Additionally, the only medical opinions addressing the etiology of the bilateral eye disabilities, aside from dry eye syndrome, weigh against the claim, Specifically, the September 2024 VA examiner opined that it was less likely than not that the Veteran's bilateral eye disabilities, aside from dry eye syndrome, were incurred in or caused by the claimed in-service event, injury or illness. In forming this conclusion, the examiner noted that the Veteran had diagnoses of bilateral open angle glaucoma, bilateral nuclear cataracts, and bilateral dermatochalasis, all of which did not have a common risk factor for an in-service event, injury or illness. A known risk factor for cataracts was natural aging while the Veteran's glaucoma was likely caused by natural aging or heredity as the Veteran's record demonstrated that he was not diagnosed with glaucoma until many years after service. The Veteran's bilateral dermatochalasis was caused by the drooping of the upper eye lid and resulted from natural aging and less elasticity of the skin as a person ages.

None of the competent medical evidence currently of record refutes this conclusion, and the Veteran has not presented or identified any such existing medical evidence or opinion.

Consequently, entitlement to service connection for bilateral eye disabilities, aside from dry eye syndrome, disability is not warranted on a direct basis.

Regarding service connection on a secondary basis, the Board again notes that the Veteran asserts that his bilateral eye disability, other than dry eye syndrome, is either caused or aggravated by his service-connected hypertension or diabetes.

However, the Board finds that the weight of the evidence is against a finding that the Veteran's current bilateral eye disability, other than dry eye syndrome, is etiologically related to the Veteran's service-connected disabilities. Notably, the most persuasive medical opinions addressing the etiology of the bilateral eye disability, other than dry eye syndrome, disability on a secondary basis weigh against the claim.

The Board again notes that the Veteran submitted an article entitled, "Secondary Glaucoma," in support of his claim in addition to a number of other articles regarding the relationship between glaucoma and diabetes.

However, the September 2024 VA examiner opined that it was less likely than not that the Veteran's claimed bilateral eye disability was caused or aggravated by his service-connected hypertension or diabetes. The examiner again noted that the Veteran's bilateral eye disabilities did not have common risk factors of hypertension or diabetes and that instead, a known risk factor for cataracts was natural aging, glaucoma was likely caused by natural aging or heredity and the Veteran's bilateral dermatochalasis resulted from natural aging and less elasticity of the skin as a person ages.

The Board finds the most recent VA examination report in September 2024 to be highly probative, as it was based on a thorough review of the Veteran's medical records, evaluation of the Veteran, and cite to relevant medical principles. The opinion is also consistent with the other evidence of record and is supported by a detailed rationale. See Prejean v. West, 13 Vet. App. 444, 448-9 (2000) (noting that factors for assessing the probative value of a medical opinion are the physician's access to the claims file and the thoroughness and detail of the opinion.).

Additionally, while the submitted articles speak in general terms regarding the claimed diseases and their potential relation to glaucoma and diabetes, the September 2024 VA examiner specifically addressed the Veteran's circumstances in relation to his eye disabilities and their potential relation to his service to include as secondary to his service-connected diabetes and hypertension disabilities.

In this regard, the Board may favor the opinion of one competent medical professional over that of another so long as an adequate statement of reasons and bases is provided. See Owens v. Brown, 7 Vet. App. 429, 433 (1995). An evaluation of the probative value of medical opinion evidence is based on the medical expert's personal examination of the patient, the examiner's knowledge and skill in analyzing the data, and the medical conclusion reached. The credibility and weight to be attached to such opinions are within the province of the Board as adjudicators. Guerrieri v. Brown, 4 Vet. App. 467 (1993).

Greater weight may be placed on one physician's opinion over another depending on factors such as reasoning employed by the physicians and whether or not and the extent
another so long as an adequate statement of reasons and bases is provided. See Owens v. Brown, 7 Vet. App. 429, 433 (1995). An evaluation of the probative value of medical opinion evidence is based on the medical expert's personal examination of the patient, the examiner's knowledge and skill in analyzing the data, and the medical conclusion reached. The credibility and weight to be attached to such opinions are within the province of the Board as adjudicators. Guerrieri v. Brown, 4 Vet. App. 467 (1993).

Greater weight may be placed on one physician's opinion over another depending on factors such as reasoning employed by the physicians and whether or not and the extent to which they reviewed prior clinical records and other evidence. Gabrielson v. Brown, 7 Vet. App. 36 (1994). The probative value of a medical opinion is generally based on the scope of the examination or review, as well as the relative merits of the expert's qualifications and analytical findings, and the probative weight of a medical opinion may be reduced if the examiner fails to explain the basis for an opinion. Sklar v. Brown, 5 Vet. App. 140 (1993).

As a result, the Board finds that the September 2024 opinion of the VA examiner to be the most probative.

Consequently, entitlement to service connection for a bilateral eye disability is also not warranted on a secondary basis.

A May 2024 Correspondence/Memorandums again indicates that the Veteran participated in a TERA during service to include exposure to herbicides.

Notably, on a September 2024 TERA examination, the VA examiner again opined that the bilateral eye disability was less likely than not caused by the indicated toxic exposure risk activity(ies), after considering the total potential exposure through all applicable military deployments of the Veteran and the synergistic, combined effet of all toxic exposure risk activities of the Veteran.

This opinion has clear conclusions and supporting data, as well as reasoned medical explanations when determining the Veteran's bilateral eye disability is less likely than not related to service, to include other toxic exposure. Stefl v. Nicholson, 21 Vet. App. 120 (2007); Nieves-Rodriguez v. Peake, 22 Vet. App. 295 (2008). This opinion is therefore afforded great probative weight. Additionally, the Board notes that there is no contrary opinion of record.

In sum, for the reasons and bases expressed above the Board finds that the most persuasive evidence is against the Veteran's claim of entitlement to service connection for a bilateral eye disability, other than dry eye syndrome. The benefit-of-the-doubt rule does not apply, and the claim must be denied. 38 U.S.C. § 5107(b).

Obstructive Sleep Apnea

The Veteran contends that his obstructive sleep apnea is directly related to his in-service herbicide agent exposure and is secondary to his high blood pressure and diabetes.

VA has again conceded the Veteran's herbicide agent exposure, and he is service connected for hypertension and diabetes.

The Veteran underwent a VA examination in August 2018. The examiner opined that the Veteran's sleep apnea was less likely than not proximately due to or the result of the Veteran's diabetes. The examiner noted that peer reviewed medical literature did not support an etiological nexus between sleep apnea and diabetes mellitus.

In a private treatment record from September 2018, the Veteran's private physician opined that the "likely cause" of the Veteran's obstructive sleep apnea was his left tonsillar hypertrophy. Relying on the Veteran's lay statements that he has had ongoing sore throat and rhinitis allergies since his deployment in Vietnam, with exposure to agent orange, the private physician stated that "[t]his may be led to chronic tonsillar enlargement."

The Veteran underwent a VA examination in August 2023. The examiner opined that the Veteran's sleep apnea was less likely than not incurred in or caused by the claimed in-service injury, event, or illness. The examiner noted that available medical records did not show signs, symptoms, complaints, diagnosis, treatments, or any chronic disability pattern concerning sleep apnea during service or within a year after service. The examiner relied on the delay between release from active duty and the Veteran's 2017 diagnosis.

The examiner also opined that that the Veteran's sleep apnea was less likely than not caused by the indicated toxic exposure risk activity(ies), after considering the total potential exposure through all applicable military deployments of the Veteran and the synergistic, combined effect of all toxic exposure risk activities of the Veteran. The examiner listed peer reviewed medical literature and indicated that the medical literature does not sustain any etiological relationship between sleep apnea and herbicide agent
or illness. The examiner noted that available medical records did not show signs, symptoms, complaints, diagnosis, treatments, or any chronic disability pattern concerning sleep apnea during service or within a year after service. The examiner relied on the delay between release from active duty and the Veteran's 2017 diagnosis.

Per the May 2024 Board remand instructions, the Veteran underwent a VA examination in September 2024. The examiner indicated that the Veteran had a diagnosis of obstructive sleep apnea that was less likely than not incurred in or caused by the claimed in-service event, injury or illness. The examiner also opined that it was less likely than not that the Veteran's obstructive sleep apnea was proximately due to, the result of, or aggravated by the Veteran's service-connected hypertension and diabetes disabilities. Finally, the examiner opined that the Veteran's obstructive sleep apnea was less likely than not caused by the indicated toxic exposure risk activity(ies), after considering the total potential exposure through all applicable military deployments of the Veteran and the synergistic, combined effet of all toxic exposure risk activities of the Veteran.

The examiner noted that the Veteran had a diagnosis of obstructive sleep apnea rather than central apnea, which would be due to central nervous system issues resulting from possible exposure. The Veteran was diagnosed with being overweight and his body mass index (BMI) was 28.6 which was in the overweight range. The leading risk factors for obstructive sleep apnea were excessive weight and obesity. The Veteran's advanced age of 78 put him at increased risk for upper airway obstruction due to age-related loosening and progressive laxity of the pharyngeal walls and the throat muscles causing blockage of air movements as he slept. It was more likely that the Veteran's obstructive sleep apnea was due to overweightness and age-related contraction of the throat. In this instance, the most obvious and likely causes were anatomic and attributing obstructive sleep apnea to herbicide exposure would be completely speculative. The examiner also noted that while hypertension had been possibly speculated to affect sleep apnea, concrete evidence in double blind studies had never been able to demonstrate a positive causal link between the condition superseding such significant risk factors as weight/obesity, small oropharynx, advanced age or smoking. The examiner noted that diabetes mellitus, when very advanced, can cause central apnea due to autonomic neuropathy. However, the examiner found no evidence of such central or autonomic dysfunction. The examiner found no evidence in the Veteran's claim file that the Veteran's hypertension or diabetes mellitus caused or aggravated his obstructive sleep apnea. The examiner also found that attributing diabetes mellitus or hypertension to the Veteran's obstructive sleep apnea would be purely speculative.

When considering the pertinent evidence of record in light of the above-noted legal authority, the Board finds that service connection for an obstructive sleep apnea disability to include as secondary to a service-connected disability is not warranted.

As there is a current diagnosis of obstructive sleep apnea, the first element of service connection is satisfied. However, a veteran seeking disability benefits must establish not only the existence of a disability, but also an etiological connection between his military service and the disability. Boyer v. West, 210 F.3d 1351, 1353 (Fed. Cir. 2000); D'Amico v. West, 209 F.3d 1322, 1326 (Fed. Cir. 2000); Hibbard v. West, 13 Vet. App. 546, 548 (2000).

The Board notes that the Veteran's service treatment records are negative for complaints or treatments for an obstructive sleep apnea disability.

The Board notes that there are conflicting medical opinions of record addressing the possibility of a relationship between the Veteran's current obstructive sleep apnea is and his service.

As noted above, a private physician in a September 2018 correspondence opined that the "likely cause" of the Veteran's obstructive sleep apnea was his left tonsillar hypertrophy as the Veteran's in-service exposure to agent orange "may be led to chronic tonsillar enlargement."

Conversely, the September 2024 VA examiner opined that it was less likely than not that the Veteran's obstructive sleep apnea disability was incurred in or caused by the claimed injury, event or illness.

In this regard, the
obstructive sleep apnea disability.

The Board notes that there are conflicting medical opinions of record addressing the possibility of a relationship between the Veteran's current obstructive sleep apnea is and his service.

In this instance, the Board finds that the September 2024 opinions of the VA examiner to be the most probative.

Regarding the September 2018 opinion of the private physician, the opinion indicated that the "likely cause" of the Veteran's obstructive sleep apnea was his left tonsillar hypertrophy as the Veteran's in-service exposure to agent orange "may be led to chronic tonsillar enlargement."

However, the Board notes that an examiner's opinion that in-service exposure to agent orange "may be led to chronic tonsillar enlargement" makes the opinion of the examiner too speculative in nature and of little probative value. See Bostain v. West, 11 Vet. App. 124, 127-28, quoting Obert v. Brown, 5 Vet. App. 30, 33 (1993) (a medical opinion expressed in terms of "may" also implies "may or may not" and is too speculative to establish a causal relationship). See also Warren v. Brown, 6 Vet. App. 4, 6 (1993) (a doctor's statement framed in terms such as "could have been" is not probative).

In contrast, the September 2024 VA examiner provided detailed medical opinions supported by pertinent rationales based upon a review of the Veteran's claims file, when concluding that the Veteran's claimed obstructive sleep apnea disability was less likely incurred in, related to or associated with his service.

When composing his September 2024 opinions, the VA examiner had the benefit of a review of the Veteran's claims file and provided more detailed rationales than the September 2018 private physician.

The September 2024 VA examiner specifically noted that the Veteran had a diagnosis of obstructive sleep apnea rather than central apnea, which would be due to central nervous system issues resulting from possible exposure. It was more likely that the Veteran's obstructive sleep apnea was due to his overweightness and age-related contraction of the throat as the most obvious and likely causes were anatomic and attributing obstructive sleep apnea to herbicide exposure would be completely speculative.

For these reasons the Board finds the September 2024 VA examiner's opinions to be the most probative regarding the issues of whether the Veteran's current obstructive sleep apnea is related to his service. See Hayes v. Brown, 5 Vet. App. 60, 69-70 (1993) ("It is the responsibility of the BVA to assess the credibility and weight to be given the evidence.") (citing Wood v. Derwinski, 1 Vet. App. 190, 192-93 (1992)). See also Guerrieri v. Brown, supra, (the probative value of medical evidence is based on the physician
apnea to herbicide exposure would be completely speculative.

For these reasons the Board finds the September 2024 VA examiner's opinions to be the most probative regarding the issues of whether the Veteran's current obstructive sleep apnea is related to his service. See Hayes v. Brown, 5 Vet. App. 60, 69-70 (1993) ("It is the responsibility of the BVA to assess the credibility and weight to be given the evidence.") (citing Wood v. Derwinski, 1 Vet. App. 190, 192-93 (1992)). See also Guerrieri v. Brown, supra, (the probative value of medical evidence is based on the physician's knowledge and skill in analyzing the data, and the medical conclusion the physician reaches; as is true of any evidence, the credibility and weight to be attached to medical opinions are within the province of the Board).

Consequently, entitlement to service connection for obstructive sleep apnea is not warranted on a direct basis.

Regarding service connection on a secondary basis, the Board again notes that the Veteran asserts that his obstructive sleep apnea is either caused or aggravated by his service-connected hypertension or diabetes.

However, the Board finds that the weight of the evidence is against a finding that a current obstructive sleep apnea disability is related to service or caused or aggravated by a service-connected disability. Again, the only medical opinions addressing the etiology of the disability on a secondary basis weigh against the claim as the September 2024 VA examiner indicated that the Veteran's obstructive sleep apnea was less likely than not caused or aggravated by his service-connected hypertension and diabetes mellitus disabilities.

In reaching this conclusion, the examiner specifically noted that while hypertension had been possibly speculated to affect sleep apnea, concrete evidence in double blind studies had never been able to demonstrate a positive causal link between the condition superseding such significant risk factors as weight/obesity, small oropharynx, advanced age or smoking. The examiner also noted that diabetes mellitus, when very advanced, can cause central apnea due to autonomic neuropathy. However, the examiner found no evidence of such central or autonomic dysfunction.

As a result, the examiner found no evidence in the Veteran's claim file that the Veteran's hypertension or diabetes mellitus caused or aggravated his obstructive sleep apnea and found that attributing diabetes mellitus or hypertension to the Veteran's obstructive sleep apnea would be purely speculative.

None of the competent medical evidence currently of record refutes these conclusions, and the Veteran has not presented or identified any such existing medical evidence or opinion.

The Board also affords the VA examiner's September 2024 opinions, which are supported by a detailed rationale and medical knowledge, great probative value.

Consequently, entitlement to service connection for an obstructive sleep apnea disability is also not warranted on a secondary basis.

A May 2024 Correspondence/Memorandums again indicates that the Veteran participated in a TERA during service to include exposure to herbicides.

Notably, on a September 2024 TERA examination, the VA examiner again opined that the obstructive sleep apnea disability was less likely than not caused by the indicated toxic exposure risk activity(ies), after considering the total potential exposure through all applicable military deployments of the Veteran and the synergistic, combined effet of all toxic exposure risk activities of the Veteran.

This opinion has clear conclusions and supporting data, as well as reasoned medical explanations when determining the Veteran's obstructive sleep apnea disability is less likely than not related to service, to include other toxic exposure. Stefl v. Nicholson, 21 Vet. App. 120 (2007); Nieves-Rodriguez v. Peake, 22 Vet. App. 295 (2008). This opinion is therefore afforded great probative weight. Additionally, the Board notes that there is no contrary opinion of record.

In sum, for the reasons and bases expressed above the Board finds that the most persuasive evidence is against the Veteran's claim of entitlement to service connection for an obstructive sleep apnea disability. The benefit-of-the-doubt rule does not apply, and the claim must be denied. 38 U.S.C. § 5107(b).

All Disabilities

The Board notes the Veteran's contentions regarding the etiology of his claimed bilateral eye and obstructive sleep apnea disabilities. To the extent that the Veteran himself contends that a medical relationship exists between his claimed bilateral eye and obstructive sleep apnea disabilities and service, the Board acknowledges that the Veteran is competent to testify as to his observations. Jandreau v. Nicholson, 492 F.3d 1372, 1376-77 (Fed. Cir. 2007). Furthermore, lay witnesses may, in some circumstances, opine on questions of diagnosis and etiology. See Davidson v. Shinseki, 581 F.3d 1313, 1316 (Fed. Cir. 2009) (finding that the Board's categorical statement that "a valid medical opinion" was required to establish nexus, and that a layperson was "not competent" to provide testimony as to nexus because she was a layperson, conflicts with Jandreau). In the instant case, however, the Board finds that bilateral eye and obstructive sleep apnea disabilities are not disabilities subject to lay diagnosis as these diagnoses require medical training.

More significantly, the Veteran and his representative do not have the medical expertise to provide an opinion regarding the claimed bilateral eye and obstructive sleep apnea disabilities etiologies. Specifically, where the determinative issue is one of medical causation, only those with specialized medical knowledge, training, or experience are competent to provide evidence on the issue. See Jones v. West, 12 Vet. App. 460, 465 (1999).

In sum, for the reasons and bases expressed above the Board finds that the most persuasive evidence is against the Veteran's claims of entitlement to service connection. The benefit-of-the-doubt rule does not apply, and the claims must be denied. 38 U.S.C. § 5107(b).

R. Bisignani

Veterans Law Judge

Board of Veterans' Appeals

Attorney for the Board James A. DeFrank

The Board's decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.

Analyze in VA Law Explorer