Clinical Practice Guideline

for

RETINAL DETACHMENT and Similar Conditions

Developed for the

Aerospace Medical Association

by their constituent organization

American Society of Aerospace Medicine Specialists

 

Overview: A retinal break is any full thickness defect in the neurosensory retina.  Retinal breaks may be classified as holes (operculated or atrophic) or tears.  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 tension.  These are considered low risk retinal breaks and almost never require treatment.  Atrophic holes occur due to retinal thinning; vitreous traction is not the pathogenic mechanism.  Atrophic retinal holes are often associated with lattice degeneration (LD).  The incidence of retinal holes in LD ranges from 18-42%.  Atrophic holes are usually located in the central lattice.  The vitreous overlying areas of LD has typically liquefied as part of the pathogenic changes associated with LD.  Atrophic holes or tears at the edge of the LD patch are associated with vitreo-retinal traction and predispose to a relatively higher risk of retinal detachment (RD) development.  Multiple holes/breaks of different types may be present in the same area of LD.  Tears in the peripheral retina typically form a horse shoe shape, result directly from vitreo-retinal traction and represents the highest risk for progression to RD.  Active vitreo-retinal traction is often associated with photopsia (spontaneous light flashes) and may be exacerbated with eye movement.

 

RD is the 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 “floaters” are common presenting complaints.  There are three primary types of RD:

 

Rhegmatogenous retinal detachment is the most common type.  The essential conditions necessary for a rhegmatogenous retinal detachment are a full thickness retinal break and vitreous liquefaction.  As the vitreous body naturally liquefies over time, structure is lost, and separation from the retina occurs except for the vitreous adherent to the far peripheral retina.  When the vitreous separates from the posterior pole of the eye, the area of the macula and optic nerve, this is termed posterior vitreous detachment (PVD).  PVD occurs typically in patients between the ages of 50 and 75 years.  Due to the tractional forces created during the evolution of a PVD, areas in the peripheral retina where the vitreous remains attached 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 RD.  Not all retinal tears progress to detachment, but, if liquefied vitreous enters the tear, it can dissect between the neurosensory retina and the RPE, resulting in a RD.  Rate of progression of the RD depends on size of the retinal break, location of the break and movements of the eye.  Loss of visual field, “curtain effect,” increases as the detachment enlarges; central visual acuity is lost when the subretinal fluid passes beneath the macula.  If high risk retinal breaks are detected early, outpatient laser retinopexy or cryopexy therapy can be successfully accomplished in the clinic setting.  This treatment is over 95% effective in preventing progression of a retinal tear to RD.  However, if an RD has developed, surgical reattachment will be required.  Surgical correction of the RD aims to relieve vitreoretinal traction, close retinal tears and holes, remove subretinal fluid and reattach the retina.  Scleral buckling techniques achieve reattachment in over 90% of cases.  An alternative or concomitant procedure is posterior vitrectomy, it relieves vitreoretinal traction by removing vitreous humor, and is successful in 75 to 90%.  Reattachment may also be aided by incisional drainage of subretinal fluid, and/or using expansile gases or silicone oil to push the retina back 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.  Visual outcome can be good if the macula is spared.  Risk of occurrence in the fellow eye is 12% within 5 years.

 

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.  These intraocular pathological conditions predispose to development of fibrous vitreo-retinal bands which contract over time.  The mechanical forces generated pull the retina from the RPE.  Treatment requires surgical lysis of the intraocular fibrous tissue by vitrectomy.  Visual outcomes are generally poor due to co-existing ocular pathology.

 

Serous (exudative) retinal detachment is usually the result of an associated medical 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 RD patients do not have full thickness retinal break.  Exudative RDs are gravity dependent.  The subretinal fluid will respond to the force of gravity and shift the location of the RD depending on the patient’s position.  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.

 

The incidence of RD is approximately 1 in 10,000.6  Risk factors for rhegmatogenous RD include advancing age, previous cataract surgery, high myopia, focal retinal atrophy (lattice degeneration) and trauma.  Lifetime risk for RD without lattice degeneration in an emmetrope is 0.3% while in a myope over -5.0 diopters life time risk is 2.2%.3  Individuals with myopia exceeding -5.0 diopters and have associated LD, the life time risk for RD increases to 35.9%.3  Detachments tend to cluster in the 20s and then again in the 40s-50s age groups.  Approximately 25% of rhegmatogenous RDs are found in patients with LD of the retina.  LD is present in approximately 10% of adults.  Severe ocular trauma is believed to be responsible for 10-15% of RDs, and up to 50% of patients who have a diagnosis of cytomegalovirus retinitis develop a rhegmatogenous RD within one year.11

 

Retinoschisis is the splitting of the retina: in the juvenile form the splitting occurs in the nerve fiber layer, and in the adult degenerative form the splitting occurs in the external plexiform layer.  Both forms of retinoschisis cause an absolute scotoma (dense visual field defect) in the corresponding visual field to the area of retina affected, whereas, retinal detachments cause a relative scotoma “curtain effect” in the visual field.  Clinical RDs occur in association with degenerative retinoschisis in up to 6% of consecutive detachment cases, but, retinoschisis is responsible for less than 2.5% of all rhegmatogenous RDs.4  There are two types of RDs associated with retinoschisis: a localized and relatively stable form with outer retinal holes only; and a symptomatic, rapidly progressive detachment with retinal breaks in both of the layers.  Localized and relatively nonprogressive RDs occur more frequently than a progressive RD by a ratio of 178:1.4  Treatment for retinoschisis should be limited to patients who develop symptomatic, progressive RDs.10

 

Aeromedical Concerns: Retinal breaks (holes and tears) can lead to RD.  RD can result in loss of visual acuity, loss of stereopsis, significant visual distortion (metamorphopsia), 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.  These sequelae are obviously key concerns for adequate performance in aviation or special operations duty.  Furthermore, consideration must be given to the risk of recurrence or involvement of the fellow eye based on the etiology (as described above).  Although routine exposure to G-forces has not been shown to increase the risk of RD, the risk is increased with pre-existing vitreoretinal abnormalities, especially in the case of tractional RD, and this should be considered in the case of unrestricted waivers.  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 RD, (i.e. subretinal fluid), are present.  This is best accomplished by a retinal specialist.

 

Medical Work-up (For military services): 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.

 

Initial waiver aeromedical summary should include the following items:

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

B.  Retinal specialist consultation (history, positive risk factors, exam findings, treatment, and surgical outcome)

 

Aeromedical Disposition (military): Potential waiver eligibility

 

Flying Class

Retinal holes

Retinal tears

Retinal detachment

Retinoschisis

Initial Flying Training

Yes, if low risk*

Maybe if successful treatment and low risk*

No

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

 

Pilots/navigators

Yes

Yes

Yes

Yes

 

Non-pilot aircrew

Yes

Yes

Yes

Yes

 

 

* 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 -5.00 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.

 

Aeromedical Disposition (civilian): The FAA hasn’t any refractive error limitations.  Should an airman develop a retinal detachment they must “ground themselves” until they are treated and meet visual acuity standards for the class applied for.  If the airman’s vision does not meet standards in the affected eye they will require a Statement of Demonstrated Ability, which may require them to take a medical flight test. The Aerospace medical Certification Division’s current pathology coding system does not permit distilling out those airmen with retinal detachment.    

 

Aeromedical Disposition (NASA): History or presence of retinal detachment is disqualifying for spaceflight duty unless secondary to trauma and having been successfully treated and no retinal tears, edema or other sequelae, and normal visual acuity and fields. 

 

Waiver Experience (military): A review of a large military waiver database through Dec 06 showed 108 cases of retinal holes, tears or retinoschisis for initial pilot/navigator training, pilots and non-pilot aircrew.  Aeromedical summaries (51) for all initial training (27), all disqualified (10) and 20 randomly selected cases were reviewed.  Sixty-one percent (31/51) had retinal holes, 23 percent (12/51) had retinoschisis and 16 percent had retinal tears (8/51).  Of the disqualified, 19 percent (6/31; 3 initial pilot/navigator training and 3 non-pilot aircrew) were retinal holes, 25 percent (2/8; 2 initial pilot/navigator training) were retinal tears and 17 (2/12; 2 initial pilot/navigator training) percent were retinoschisis.  Of the 10 disqualified, all were disqualified because of their eye condition(s) except one who also had depression.

 

Review of the same database through mid-Dec 06 showed 31 cases of retinal detachment in initial pilot/navigator training (2), pilots (20) and non-pilot aircrew (9) flyers.  Twenty-two (71%) were granted waivers and nine (29%) were disqualified.  Of the nine disqualified, five were on initial flying class exams, three were disqualified because of below normal best corrected visual acuity the effected eye, and one was disqualified for other unrelated medical conditions. 

 

Waiver Experience (civilian): N/A

 

Waiver Experience (NASA): Retinal detachment would be considered for waiver for space flight duty following repair of a detached retina if visual acuity and fields are normal and ophthalmology opinion is that recurrence is unlikely.

 

References:

 

1.  Anand, R.  Chapter 37 – Serous Detachment of the Neural Retina.  In Ophthalmology, 2nd Edition  Ed by Yanoff, M, et al.  Mosby, 2004.

 

2.  Arroyo, JG.  Retinal tear and detachment.  UpToDate.  Online version 14.3.  February 24, 2006.

 

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

 

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

 

5.  Flynn, HW Jr, et al.  Chap XI Peripheral Retinal Abnormalities.  In Basic and Clinical Sciences, Section 12: Retina and Vitreous.  American Academy of Ophthalmology.  2003.

 

6.  Gariano, RF and Chang-hee, K.  Evaluation and Management of Suspected Retinal Detachment.  American Family Physician.  2004 July; 69(7):  1691-98.

 

7.  Green, RP and Chou, TY.  Retinal Detachment in U.S. Air Force Flyers.  Aviation, Space and Environmental Medicine.  1996 September; 67(9):  874-9.

 

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

 

9.  Ross, W and Stockl, F.  Visual Recovery After Retinal Detachment.  Current Opinion in Ophthalmology.  2000 June; 11(3):  191-94.

 

10.  Tasman, WS.  Chapter 134 – Peripheral Retinal Lesions. In Ophthalmology, 2d Edition  Ed by Yanoff, M, et al.  Mosby, 2004.

 

11.  Wilkinson CP.  Chapter 136 – Rhegmatogenous Retinal Detachment.  In Ophthalmology, 2d Edition.  Ed by Yanoff, M, et al.  Mosby, 2004.

 

 

Updated: January 19, 2008