Air Force Waiver Guide




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Peripheral Retinal Breaks (Holes & Tears), Retinal Detachment & Retinoschisis Mar 11)



I. Overview.


A retinal break is any full thickness defect in the neurosensory retina.1-2 Retinal breaks may be classified as holes (operculated, atrophic, macular), tears (horseshoe or flap), or dialyses. Classification aims to predict retinal breaks that are not likely to cause severe visual sequelae from those that are more likely to lead to visual loss and retinal detachment. Operculated holes are round defects in the neural retina with an overlying operculum of retinal tissue, caused by vitreous traction that has been relieved of its tension.1-2 These are considered low risk retinal breaks and almost never require treatment. Atrophic holes occur due to retinal thinning and are often associated with lattice degeneration, a common condition that exists in 6%-10% of the general population.2 Atrophic holes or tears at the edge of the lattice that are associated with vitreo-retinal traction or sub-retinal fluid predispose to a relatively higher risk of retinal detachment. Tears in the peripheral retina are typically horseshoe shaped resulting from vitreo-retinal traction and represent the highest risk for progression to retinal detachment. The stimulus produced by active vitreo-retinal traction often manifests as photopsias and may be exacerbated with eye movement.1 Lastly, dialyses are linear retinal breaks that occur peripherally along the ora serrata. Although most dialyses are associated with blunt ocular trauma, they can also occur spontaneously. Dialyses also impart intermediate risk for retinal detachment and necessitate treatment. Macular hole is a term used to describe many different macular vitreoretinal disturbances. Idiopathic macular holes typically occur in the sixth to eighth decades of life and are thought to be caused by tractional forces of perifoveal vitreous detachments.1 Idiopathic macular holes have the potential to greatly affect central vision and often warrant posterior vitrectomy surgery. Their potential to cause retinal detachment is small but other sequelae such as epiretinal membrane formation are often observed.


c:\users\john.brewer\pictures\4gonio_atropic_holes.jpgc:\users\john.brewer\pictures\macular hole.jpgc:\users\john.brewer\pictures\horsehoe tear.jpgc:\users\john.brewer\pictures\lattice degeneration.jpg

Top Left: Peripheral retinal holes, Top right: idiopathic macular hole, Bottom Left: large retinal horseshoe tear, Bottom Right: peripheral lattice degeneration

Retinal detachment is a separation of the neurosensory retina from the underlying retinal pigment epithelium (RPE), resulting in loss of the corresponding visual field in the affected eye. If the detachment involves the macula, central visual acuity will be compromised. Visual field disturbance and/or new onset of “flashes and floaters” are common presenting complaints. Of the three classifications for retinal detachments, rhegmatogenous type is the most common. The essential conditions necessary for a rhegmatogenous retinal detachment are a full thickness retinal break and vitreous liquefaction. Vitreous syneresis is the natural history of vitreous liquification over time and initially results in symptoms of floaters. As the vitreous liquefies, it separates from areas of the retina where it is not firmly attached resulting in a posterior vitreous detachment (PVD) or what is commonly noted by patients as an acute “new” floater. Posterior vitreous detachments typically occur in patients between the ages of 50 and 75 years of age. Autopsy studies demonstrate PVD in less than 10% of patients under 50 years of age but were present in 63% of those over the age of 70 years.1 Additionally, the tractional forces generated during the evolution of a PVD can result in a retinal tear. Approximately 50% of patients who develop full thickness horse shoe retinal tears in the setting of a symptomatic PVD will develop a rhegmatogenous retinal detachment secondary to liquefied vitreous entering the tear and dissecting between the neurosensory retina and the RPE. Additionally, severe ocular trauma is believed to be responsible for 10-15% of retinal detachments, and half of patients who have a diagnosis of cytomegalovirus retinitis develop a rhegmatogenous retinal detachment within one year. Risk of occurrence in the fellow eye is significantly increased, provided that additional acquired risk factors are comparable. The annual incidence of retinal detachment is approximately 1 in 10,000.5 Advanced age, previous intra-ocular surgery, high myopia, lattice degeneration, and trauma increase the lifetime risk of developing retinal detachment. Myopic patients with over -5.0 diopters of error have a lifetime risk of 2.2%.3 In individuals that have myopia exceeding -5.0 diopters and associated lattice, the lifetime risk for retinal detachment increases to 35.9%.6 Retinal detachment incidence tends to be bimodal, peaking in the third decade of life and then again in the 5th to 6th decades. The rate of progression of the retinal detachment depends on size of the retinal break, location of the break and movements of the eye. Symptoms, such as loss of visual field in the form of a descending veil or curtain, increase as the detachment enlarges and may affect central visual acuity when the macula is involved. However, if high risk retinal breaks are detected before progression to retinal detachment, laser retinopexy or cryopexy therapy can be employed and are over 95% effective in preventing progression of a retinal tear to rhegmatogenous retinal detachment.


Once a retinal detachment has developed, surgical reattachment of the retina requires relief of vitreoretinal traction, closing of retinal tears and holes, and removing subretinal fluid. Scleral buckling techniques achieve a rate of reattachment of over 90%.9 An alternative or concomitant procedure is posterior vitrectomy which relieves vitreoretinal traction by removing the vitreous. Reattachment may also be aided by incisional drainage of subretinal fluid, and using expansile gases or silicone oil to tamponade the retina into place. Although surgical treatment can result in 90% anatomical cure (permanent reattachment), visual outcomes can vary based on the etiology, length of time of detachment, and involvement of the macula. Normal visual acuity is often maintained if the macula is spared.




The process of PVD formation leading to retinal tears and eventual rhegmatogenous retinal detachment.2


Conversely, a tractional retinal detachment usually results from an ongoing or previous inflammatory, infectious, or surgical process, such as proliferative diabetic retinopathy, retinopathy of prematurity, sickle cell retinopathy, or penetrating trauma which causes the development of fibrous vitreo-retinal bands. Over time these bands contract, generating enough mechanical force to pull the retina away from the underlying RPE. Treatment requires surgical lysis of the intraocular fibrous tissue by vitrectomy. Visual outcomes are generally poor due to co-existing ocular pathologies.


Serous or exudative retinal detachment is typically the result of an associated systemic process (acute hypertension, inflammation, neoplasm, etc.) that damages either retinal blood vessels or the RPE allowing fluid to pass into the subretinal space. In exudative retinal detachment, patients do not have a full thickness retinal break. Exudative retinal detachment are gravity dependent and have a smooth border. The subretinal fluid will respond to the force of gravity and shift the location of the retinal detachment depending on the patient’s position.1 Traditional retinal reattachment surgeries are not effective. Treatment requires addressing the underlying disease process. If the underlying medical condition is successfully treated, visual outcomes can be very good.


Degenerative retinoschisis is a splitting of the retina but is asymptomatic in most cases. Bullous retinoschisis may imitate retinal detachment in clinical appearance and can progress to retinal detachment when holes exist in the outer layers of the schisis.8 In the typical form, splitting occurs in the outer plexiform layer and is seen as smooth, oval elevation. Reticular retinoschisis occurs in the nerve fiber layer and often extends posteriorly toward the equator. Both forms of retinoschisis can cause an absolute scotoma (dense visual field defect) in the visual field when progression of the schisis cavity extends posterior toward the equator, whereas, retinal detachments cause a relative scotoma (most commonly a curtain or veil-like effect) in the visual field. Studies have shown a linkage between retinal detachments and retinoschisis, with an incidence of 2.5% of degenerative retinoschisis in rhegmatogenous retinal detachments.7-8 Treatment for retinoschisis should be limited to patients who develop symptomatic, progressive retinoschisis leading to retinal detachments.8


II. Aeromedical Concerns.


Retinal holes and tears can lead to retinal detachment. Retinal detachment can result in loss of visual acuity, loss of stereopsis, visual distortion, visual field loss, relative night blindness, reduced color vision, and lowered contrast sensitivity. The specific visual impact depends on the area and extent of the retina involved and the success of any reattachment surgery. Consideration must also be given to the risk of progression, recurrence or involvement of the fellow eye based on the mechanism of retinal pathology, or type of retinal detachment. Although routine exposure to G-forces has not been shown to increase the risk of retinal detachment, the risk is increased with pre-existing vitreoretinal abnormalities, especially in the case of tractional retinal detachment, and this should be considered in the case of unrestricted waivers. All patients with documented retinal holes or breaks should have their manifest refractions included in the Aeromedical Consultation Service (ACS) referrals (these should be pre-corneal refractive surgery measurements if applicable). All retinal breaks need careful examination to identify the types of holes present and to determine if active vitreo-retinal traction or other signs of impending retinal detachment are present. This is best accomplished by a vitreo-retinal subspecialist but should also be reviewed by the ACS once the underlying disease process has stabilized.


III. Waiver Consideration.


These retinal defects are all disqualifying for Flying Classes I/IA, II, IIU, and III. Although not listed specifically for ATC/GBC and SMOD duties as disqualifying, most significant retinal defects are disqualifying for retention purposes and will therefore require a waiver for continued ATC/GBC and SMOD duties.


Table 1: Waiver potential for retinal holes, retinal detachment, and retinoschisis

Flying Class

Retinal holes

Retinal tears

Retinal detachment

Retinoschisis

Waiver Authority

Required ACS evaluation/review

I/IA, initial FC II and III

Yes, if low risk*

Maybe if successful treatment and low risk*

No

Maybe, if small and isolated in far peripheral retina and low risk*


AETC

ACS review/evaluation

II/IIU#

Yes

Yes

Yes

Yes


MAJCOM

ACS review/evaluation for initial waiver

III

Yes

Yes

Yes

Yes


MAJCOM

ACS review for initial waiver

ATC/

GBC

N/A^

N/A^

Yes

N/A^

MAJCOM

ACS review for initial waiver

SMOD

N/A^

N/A^

Yes

N/A^

AFSPC or GSC

ACS review at discretion of the waiver authority

* Low risk features for retinal detachment are defined as absence of symptoms (flashes or floaters), no prior history of retinal detachment, no subretinal fluid, myopia less than -5.50 diopters, and no evidence of vitreo-retinal traction. In addition, there should be no retinal breaks at the edge or outside the area of lattice degeneration, except in the case of operculated peripheral retinal hole.

# Waiver authority for FC IIU is AFMSA.

^ Not disqualifying if treated and/or determined to be stable by a vitreo-retina specialist


AIMWITS search in Feb 2011 revealed a total of 289 individuals with an aeromedical summary containing the diagnosis of retinal hole, retinal detachment or retinoschisis. There were 36 total disqualifications. Breakdown of cases was as follows: 45 FC I/IA (16 disqualifications); 149 FC II (5 disqualifications); 86 FC III (15 disqualifications); 1 FC IIU; 4 ATC/GBC; and 4 SMOD. The latter three categories had no disqualified individuals. The vast majority of the disqualified cases were related to the retinal problem, particularly if the waiver was for an initial certification case.


IV. Information Required for Waiver Submission.


Aeromedical disposition and waiver submission should only be submitted after clinical disposition has been completed and all appropriate treatments have been initiated using best current clinical guidelines/recommendations. For retinal holes, tears, retinal detachment and retinoschisis, initial waiver submission should be accompanied by a bilateral peripheral retina examination note by a retinal specialist. If the retinal specialist determines surgical treatment is required then waiver submission should occur after adequate recovery time without complications (three month minimum). If the retinal specialist determines no treatment is required then the 3 month waiting period prior to waiver submission is not required. All initial waivers (or recurrence of retinal tear or detachment) require an ACS evaluation/review.


The aeromedical summary for the initial waiver for retinal hole, retinal detachment, and retinoschisis should include the following:

A. List and fully discuss all clinical diagnoses requiring a waiver.

B. Complete aeromedical history to include pertinent negatives (trauma, myopia, lattice degeneration, etc.).

C. Retinal specialist consultation to include: history, positive risk factors, exam findings to include manifest refraction (prior to any corneal refractive surgery), treatment(s), and surgical outcome.


The aeromedical summary for waiver renewal for retinal hole, retinal detachment, and retinoschisis should include the following:

A. Interval history to include presence or absence of current visual symptoms and operational impact of condition.

B. Results of interval ophthalmology exams.

C. Summary of any medical or surgical treatments.


ICD 9 codes for retinal hole, retinal detachment, and retinoschisis

361.3

361.31

Retinal Holes

361.0

361.2

361.8

361.9

Retinal Detachment

361.1

Retinoschisis


V. References.


1. Kline LB, Arnold AC, Eggenberger E, Foroozan R, Golnik KC, Rizzo JF, Shaw HE. Neuro-Ophthalmology. Basic and Clinical Science Course, American Academy of Ophthalmology, pp 129-134, 2007.


2. Greven, CM. Chapter 135 – Retinal Breaks. Ophthalmology, 2d Edition. Ed by Yanoff, M, et al. Mosby, 2004.


3. Byer, NE. Long-Term Natural History Study of Senile Retinoschisis with Implications for Management. Ophthalmology. 1986 September; 93(9): 1127-36.


4. Wilkinson CP Rhegmatogenous Retinal Detachment. Ch. 6.38 in Yanoff & Duker: Ophthalmology, Mosby, 2008.


5. Burton, TC. The Influence of Refractive Error and Lattice Degeneration on the Incidence of Retinal Detachment. Trans Am Ophthalmol Soc, 1989; 87: 143-57.


6. Tasman, WS. Chapter 8.37 – Peripheral Retinal Lesions. Ophthalmology, Ed by Yanoff, M, et al. Mosby, 1999.


7. Williams, GA Chapter 8.5 – Scleral Buckling Surgery. Ophthalmology, Ed by Yanoff, M, et al. Mosby, 1999.


WAIVER GUIDE

Updated: Oct 2011

Supersedes Waiver Guide of Jan 2008

By: LtCol Laura Brodhag (RAM 12) and Dr Dan Van Syoc

Waiver Guide reviewed by the AF/SG Consultant for Rheumatology, Col William E Venanzi


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